Multifilter Rotating Shadowband Radiometer (MFRSR) Handbook
Hodges, GB; Michalsky, JJ
2011-02-07T23:59:59.000Z
The visible Multifilter Rotating Shadowband Radiometer (MFRSR) is a passive instrument that measures global and diffuse components of solar irradiance at six narrowband channels and one open, or broadband, channel (Harrison et al. 1994). Direct irradiance is not a primary measurement, but is calculated using the diffuse and global measurements. To collect one data record, the MFRSR takes measurements at four different shadowband positions. The first measurement is taken with the shadowband in the nadir (home) position. The next three measurements are, in order, the first side-band, sun-blocked, and second side-band. The side-band measurements are used to correct for the portion of the sky obscured by the shadowband. The nominal wavelengths of the narrowband channels are 415, 500, 615, 673, 870, and 940 nm. From such measurements, one may infer the atmosphere's aerosol optical depth at each wavelength. In turn, these optical depths may be used to derive information about the column abundances of ozone and water vapor (Michalsky et al. 1995), as well as aerosol (Harrison and Michalsky 1994) and other atmospheric constituents.
ARM Multi-Filter Rotating Shadowband Radiometer (MFRSR): irradiances
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Hodges, Gary
The multifilter rotating shadowband radiometer (MFRSR) takes spectral measurements of direct normal, diffuse horizontal and total horizontal solar irradiances. These measurements are at nominal wavelengths of 415, 500, 615, 673, 870, and 940 nm. The measurements are made at a user-specified time interval, usually about one minute or less. The sampling rate for the Atmospheric Radiation Measurement (ARM) Climate Research Facility MFRSRs is 20 seconds. From such measurements, one may infer the atmosphere's optical depth at the wavelengths mentioned above. In turn, these optical depths may be used to derive information about the column abundances of ozone and water vapor (Michalsky et al. 1995), as well as aerosol (Michalsky et al. 1994) and other atmospheric constituents. A silicon detector is also part of the MFRSR. This detector provides a measure of the broadband direct normal, diffuse horizontal and total horizontal solar irradiances. A MFRSR head that is mounted to look vertically downward can measure upwelling spectral irradiances. In the ARM system, this instrument is called a multifilter radiometer (MFR). At the Southern Great Plains (SGP) there are two MFRs; one mounted at the 10-m height and the other at 25 m. At the North Slope of Alaska (NSA) sites, the MFRs are mounted at 10 m. MFRSR heads are also used to measure normal incidence radiation by mounting on a solar tracking device. These are referred to as normal incidence multi-filter radiometers (NIMFRs) and are located at the SGP and NSA sites. Another specialized use for the MFRSR is the narrow field of view (NFOV) instrument located at SGP. The NFOV is a ground-based radiometer (MFRSR head) that looks straight up.
Kassianov, Evgueni I.; Flynn, Connor J.; Koontz, Annette S.; Sivaraman, Chitra; Barnard, James C.
2013-09-11T23:59:59.000Z
Well-known cloud-screening algorithms, which are designed to remove cloud-contaminated aerosol optical depths (AOD) from AOD measurements, have shown great performance at many middle-to-low latitude sites around the world. However, they may occasionally fail under challenging observational conditions, such as when the sun is low (near the horizon) or when optically thin clouds with small spatial inhomogeneity occur. Such conditions have been observed quite frequently at the high-latitude Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) sites. A slightly modified cloud-screening version of the standard algorithm is proposed here with a focus on the ARM-supported Multifilter Rotating Shadowband Radiometer (MFRSR) and Normal Incidence Multifilter Radiometer (NIMFR) data. The modified version uses approximately the same techniques as the standard algorithm, but it additionally examines the magnitude of the slant-path line of sight transmittance and eliminates points when the observed magnitude is below a specified threshold. Substantial improvement of the multi-year (1999-2012) aerosol product (AOD and its Angstrom exponent) is shown for the NSA sites when the modified version is applied. Moreover, this version reproduces the AOD product at the ARM Southern Great Plains (SGP) site, which was originally generated by the standard cloud-screening algorithms. The proposed minor modification is easy to implement and its application to existing and future cloud-screening algorithms can be particularly beneficial for challenging observational conditions.
Retrievals of cloud optical depth and effective radius from Thin-Cloud Rotating Shadowband December 2011. [1] A Thin-Cloud Rotating Shadowband Radiometer (TCRSR) was developed and deployed) through an optically thin cloud (optical depth
RETRIEVALS OF CLOUD OPTICAL DEPTH AND EFFECTIVE RADIUS FROM A THIN-CLOUD ROTATING SHADOWBAND Division Brookhaven National Laboratory U.S. Department of Energy Office of Science ABSTRACT A thin cloud cloud. We applied Min and Duan's retrieval algorithm to the field measurements of TC-RSR to derive cloud
, environmental scientists are concerned about the effects of aerosols due to their capacity to warm and/or cool the planet. The focus here is to calculate optical and size parameters of aerosols by measuring the radiation
Myers, D. R.
2009-03-01T23:59:59.000Z
The availability of rotating shadow band radiometer measurement data at several new stations provides an opportunity to compare historical satellite-based estimates of solar resources with measurements. We compare mean monthly daily total (MMDT) solar radiation data from eight years of NSRDB and 22 years of NASA hourly global horizontal and direct beam solar estimates with measured data from three stations, collected after the end of the available resource estimates.
Aerosol Optical Depth Value-Added Product Report
Koontz, A; Hodges, G; Barnard, J; Flynn, C; Michalsky, J
2013-03-17T23:59:59.000Z
This document describes the process applied to retrieve aerosol optical depth (AOD) from multifilter rotating shadowband radiometers (MFRSR) and normal incidence multifilter radiometers (NIMFR) operated at the ARM Climate Research Facility’s ground-based facilities.
NREL: MIDC/Oak Ridge National Laboratory Rotating Shadowband Radiometer
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ARM - Field Campaign - Thin Cloud Rotating Shadowband Radiometer
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ARM - Publications: Science Team Meeting Documents: Rotating Shadowband
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Removing Systematic Errors from Rotating Shadowband Pyranometer Data Frank Vignola
Oregon, University of
of the pyranometer to briefly shade the pyranometer once a minute. Direct hori- zontal irradiance is calculated used in programs evaluating the performance of photovoltaic systems, and systematic errors in the data
Dong, X. Y.; De Robertis, M. M., E-mail: xydong@yorku.ca [Physics and Astronomy Department, York University, Toronto, ON M3J 1P3 (Canada)
2013-10-01T23:59:59.000Z
This is the second paper of the series Detecting Active Galactic Nuclei Using Multi-filter Imaging Data. In this paper we review shapelets, an image manipulation algorithm, which we employ to adjust the point-spread function (PSF) of galaxy images. This technique is used to ensure the image in each filter has the same and sharpest PSF, which is the preferred condition for detecting AGNs using multi-filter imaging data as we demonstrated in Paper I of this series. We apply shapelets on Canada-France-Hawaii Telescope Legacy Survey Wide Survey ugriz images. Photometric parameters such as effective radii, integrated fluxes within certain radii, and color gradients are measured on the shapelets-reconstructed images. These parameters are used by artificial neural networks (ANNs) which yield: photometric redshift with an rms of 0.026 and a regression R-value of 0.92; galaxy morphological types with an uncertainty less than 2 T types for z ? 0.1; and identification of galaxies as AGNs with 70% confidence, star-forming/starburst (SF/SB) galaxies with 90% confidence, and passive galaxies with 70% confidence for z ? 0.1. The incorporation of ANNs provides a more reliable technique for identifying AGN or SF/SB candidates, which could be very useful for large-scale multi-filter optical surveys that also include a modest set of spectroscopic data sufficient to train neural networks.
2011-11-26T23:59:59.000Z
by a certain angle, then with respect to another axis by another angle and so on. It would be probably different if we were fish or birds. We consider rotations with ...
Ocean Aerosols: The Marine Fast-Rotating Shadow-Band Radiometer Network
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million Cubic Feet) Natural GasSpeedingScientificPhase inDirectives, Delegations, andOcean
NREL: MIDC/SMUD Anatolia Rotating Shadowband Radiometer (38.55 N, 121.24 W,
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journalhttp://www.fnal.gov/directorate/nalcal/nalcal02_07_05_files/nalcal.gifSolar Energy The following resources can provide51 m, GMT-8)
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Maxey, C.; Andreas, A.
This measurement station monitors global horizontal, direct normal, and diffuse horizontal irradiance to define the amount of solar energy that hits this particular location.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Maxey, C.; Andreas, A.
A partnership with industry and U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to collect solar data to support future solar power generation in the United States. The measurement station monitors global horizontal, direct normal, and diffuse horizontal irradiance to define the amount of solar energy that hits this particular location. The solar measurement instrumentation is also accompanied by meteorological monitoring equipment to provide scientists with a complete picture of the solar power possibilities.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Lustbader, J.; Andreas, A.
This measurement station at NREL's Vehicle Testing and Integration Facility (VTIF) monitors global horizontal, direct normal, and diffuse horizontal irradiance to define the amount of solar energy that hits this particular location. The solar measurement instrumentation is also accompanied by meteorological monitoring equipment.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Wilcox, S.; Andreas, A.
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Stoffel, T.; Andreas, A.
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Wilcox, S.; Andreas, A.
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Wilcox, S.; Andreas, A.
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Wilcox, S.; Andreas, A.
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Wilcox, S.; Andreas, A.
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Wilcox, S.; Andreas, A.
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
Changes to MFRSRCLDOD1MIN Datastream
S McFarlane and Y Shi
2012-05-23T23:59:59.000Z
Significant updates were made to the multifilter rotating shadowband radiometer (MFRSR) cloud optical depth (MFRSRCLDOD) value-added product (VAP) in 2011. The original intent of the update was to add quality control (QC) flags and to update the VAP to use the improved retrievals of liquid water path (LWP) from the Microwave Radiometer Retrievals (MWRRET) VAP rather than the statistical retrievals of LWP from the Microwave Radiometer Line of Sight (MWRLOS) datastream. Although this was originally intended to be a straightforward update of the code, it became more complicated due to the following factors: (1) a new developer and translator team were working with the code; (2) numerous small changes had to be made to the code to consistently implement the QC flags; and (3) ARM standards have changed over the years since the code was originally developed.
Aerosol Retrievals from ARM SGP MFRSR Data
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Alexandrov, Mikhail
The Multi-Filter Rotating Shadowband Radiometer (MFRSR) makes precise simultaneous measurements of the solar direct normal and diffuse horizontal irradiances at six wavelengths (nominally 415, 500, 615, 673, 870, and 940 nm) at short intervals (20 sec for ARM instruments) throughout the day. Time series of spectral optical depth are derived from these measurements. Besides water vapor at 940 nm, the other gaseous absorbers within the MFRSR channels are NO2 (at 415, 500, and 615 nm) and ozone (at 500, 615, and 670 nm). Aerosols and Rayleigh scattering contribute atmospheric extinction in all MFRSR channels. Our recently updated MFRSR data analysis algorithm allows us to partition the spectral aerosol optical depth into fine and coarse modes and to retrieve the fine mode effective radius. In this approach we rely on climatological amounts of NO2 from SCIAMACHY satellite retrievals and use daily ozone columns from TOMS.
ROTATION-VIBRATION TETRAHEDRAL
SadovskiÃ, DmitriÃ
ANALYSIS OF ROTATION-VIBRATION RELATIVE EQUILIBRIA ON THE EXAMPLE OF A TETRAHEDRAL FOUR ATOM (RE) of a nonrigid molecule which vibrates about a well de#12;ned equilibrium con#12;guration and rotates as a whole. Our analysis uni#12;es the theory of rotational and vibrational RE. We rely
Ronaldo Levenhagen; Nelson Vani Leister; Juan Zorec; Yves Fremat
2005-09-07T23:59:59.000Z
Fast rotation seems to be the major factor to trigger the Be phenomenon. Surface fast rotation can be favored by initial formation conditions such as metal abundance. Models of fast rotating atmospheres and evolutionary tracks are used to determine the stellar fundamental parameters of 120 Be stars situated in spatially well-separated regions to imply there is between them some gradient of metallicity. We study the effects of the incidence of this gradient on the nature of the studied stars as fast rotators.
Burra G. Sidharth
2010-04-27T23:59:59.000Z
Numerous observations and studies suggest that the universe has some sort of overall rotation. We consider this matter and provide a new angle.
Kevin Cahill
2006-12-24T23:59:59.000Z
The way a field transforms under rotations determines its statistics--as is easy to see for scalar, Dirac, and vector fields.
Diamagnetism of rotating plasma
Young, W. C.; Hassam, A. B.; Romero-Talamas, C. A.; Ellis, R. F.; Teodorescu, C. [IREAP, University of Maryland, College Park, Maryland 20742 (United States)
2011-11-15T23:59:59.000Z
Diamagnetism and magnetic measurements of a supersonically rotating plasma in a shaped magnetic field demonstrate confinement of plasma pressure along the magnetic field resulting from centrifugal force. The Grad-Shafranov equation of ideal magnetohydrodynamic force balance, including supersonic rotation, is solved to confirm that the predicted angular velocity is in agreement with spectroscopic measurements of the Doppler shifts.
Rotational cavity optomechanics
Bhattacharya, M
2015-01-01T23:59:59.000Z
We theoretically examine the optomechanical interaction between a rotating nanoparticle and an orbital angular momentum-carrying optical cavity mode. Specifically, we consider a dielectric nanosphere rotating uniformly in a ring-shaped optical potential inside a Fabry-Perot resonator. The motion of the particle is probed by a weak angular lattice, created by introducing two additional degenerate Laguerre-Gaussian cavity modes carrying equal and opposite orbital angular momenta. We demonstrate that the rotation frequency of the nanoparticle is imprinted on the probe optical mode, via the Doppler shift, and thus may be sensed experimentally using homodyne detection. We show analytically that the effect of the optical probe on the particle rotation vanishes in the regime of linear response, resulting in an accurate frequency measurement. We also numerically characterize the degradation of the measurement accuracy when the system is driven in the nonlinear regime. Our results are relevant to rotational Doppler ve...
A Rotating Holographic Superconductor
Julian Sonner
2009-03-31T23:59:59.000Z
In this paper we initiate the study of SSB in 3+1 dimensional rotating, charged, asymptotically AdS black holes. The theory living on their boundary, R x S^2, has the interpretation of a 2+1 dimensional rotating holographic superconductor. We study the appearance of a marginal mode of the condensate as the temperature is decreased. We find that the transition temperature depends on the rotation. At temperatures just below T_c, the transition temperature at zero rotation, there exists a critical value of the rotation, which destroys the superconducting order. This behaviour is analogous to the emergence of a critical applied magnetic field and we show that the superconductor in fact produces the expected London field in the planar limit.
Rotating holographic superconductor
Sonner, Julian [Blackett Laboratory, Imperial College, London, SW7 2AZ (United Kingdom) and Trinity College, University of Cambridge, Cambridge, CB2 1TQ (United Kingdom)
2009-10-15T23:59:59.000Z
In this paper we initiate the study of spontaneous symmetry breaking in 3+1 dimensional rotating, charged, asymptotically AdS black holes. The theory living on their boundary, RxS{sup 2}, has the interpretation of a 2+1 dimensional rotating holographic superconductor. We study the appearance of a marginal mode of the condensate as the temperature is decreased. We find that the transition temperature depends on the rotation. At temperatures just below T{sub c}, the transition temperature at zero rotation, there exists a critical value of the rotation, which destroys the superconducting order. This behavior is analogous to the emergence of a critical applied magnetic field and we show that the superconductor in fact produces the expected London field in the planar limit.
Bianchini, P.; Varri, A. L. [Now at Department of Astronomy, Indiana University, 727 East 3rd Street, Swain West 319, Bloomington, IN 47405-7105 (United States); Bertin, G.; Zocchi, A., E-mail: bianchini@mpia.de [Dipartimento di Fisica, Universita degli Studi di Milano, via Celoria 16, I-20133 Milano (Italy)
2013-07-20T23:59:59.000Z
Internal rotation is thought to play a major role in the dynamics of some globular clusters. However, in only a few cases has internal rotation been studied by the quantitative application of realistic and physically justified global models. Here, we present a dynamical analysis of the photometry and three-dimensional kinematics of {omega} Cen, 47 Tuc, and M15, by means of a recently introduced family of self-consistent axisymmetric rotating models. The three clusters, characterized by different relaxation conditions, show evidence of differential rotation and deviations from sphericity. The combination of line-of-sight velocities and proper motions allows us to determine their internal dynamics, predict their morphology, and estimate their dynamical distance. The well-relaxed cluster 47 Tuc is interpreted very well by our model; internal rotation is found to explain the observed morphology. For M15, we provide a global model in good agreement with the data, including the central behavior of the rotation profile and the shape of the ellipticity profile. For the partially relaxed cluster {omega} Cen, the selected model reproduces the complex three-dimensional kinematics; in particular, the observed anisotropy profile, characterized by a transition from isotropy to weakly radial anisotropy and then to tangential anisotropy in the outer parts. The discrepancy found for the steep central gradient in the observed line-of-sight velocity dispersion profile and for the ellipticity profile is ascribed to the condition of only partial relaxation of this cluster and the interplay between rotation and radial anisotropy.
Rongkuo Zhao; Alejandro Manjavacas; F. Javier García de Abajo; J. B. Pendry
2012-09-25T23:59:59.000Z
We investigate the frictional forces due to quantum fluctuations acting on a small sphere rotating near a surface. At zero temperature, we find the frictional force near a surface to be several orders of magnitude larger than that for the sphere rotating in vacuum. For metallic materials with typical conductivity, quantum friction is maximized by matching the frequency of rotation with the conductivity. Materials with poor conductivity are favored to obtain large quantum frictions. For semiconductor materials that are able to support surface plasmon polaritons, quantum friction can be further enhanced by several orders of magnitude due to the excitation of surface plasmon polaritons.
Donu Arapura
2013-01-07T23:59:59.000Z
Chapter 1. Algebra of Rotations. One of our goals is to make precise the idea of symmetry, which is important in math and other parts of science. Something like ...
Sandia Energy - Rotating Platform
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
the rotating platform for trough modules: Steady-state Efficiency vs. T Out-of-Focus Heat Loss vs. T during nighttime clear sky conditions Incident Angle Efficiency vs....
Hunter, Steven L. (Livermore, CA)
2002-01-01T23:59:59.000Z
A rate sensor for angular/rotational acceleration includes a housing defining a fluid cavity essentially completely filled with an electrolyte fluid. Within the housing, such as a toroid, ions in the fluid are swept during movement from an excitation electrode toward one of two output electrodes to provide a signal for directional rotation. One or more ground electrodes within the housing serve to neutralize ions, thus preventing any effect at the other output electrode.
I. V. Fialkovsky; D. V. Vassilevich
2012-11-29T23:59:59.000Z
We study magneto--optical properties of monolayer graphene by means of quantum field theory methods in the framework of the Dirac model. We reveal a good agreement between the Dirac model and a recent experiment on giant Faraday rotation in cyclotron resonance. We also predict other regimes when the effects are well pronounced. The general dependence of the Faraday rotation and absorption on various parameters of samples is revealed both for suspended and epitaxial graphene.
Rusnak, Brian (Livermore, CA); Hall, James M. (Livermore, CA); Shen, Stewart (Danville, CA); Wood, Richard L. (Santa Fe, NM)
2005-01-18T23:59:59.000Z
A rotating aperture system includes a low-pressure vacuum pumping stage with apertures for passage of a deuterium beam. A stator assembly includes holes for passage of the beam. The rotor assembly includes a shaft connected to a deuterium gas cell or a crossflow venturi that has a single aperture on each side that together align with holes every rotation. The rotating apertures are synchronized with the firing of the deuterium beam such that the beam fires through a clear aperture and passes into the Xe gas beam stop. Portions of the rotor are lapped into the stator to improve the sealing surfaces, to prevent rapid escape of the deuterium gas from the gas cell.
Pepper, W.B.
1984-05-09T23:59:59.000Z
A rotating parachute for decelerating objects travelling through atmosphere at subsonic or supersonic deployment speeds includes a circular canopy having a plurality of circumferentially arranged flexible panels projecting radially from a solid central disk. A slot extends radially between adjacent panels to the outer periphery of the canopy. Upon deployment, the solid disk diverts air radially to rapidly inflate the panels into a position of maximum diameter. Air impinging on the panels adjacent the panel slots rotates the parachute during its descent. Centrifugal force flattens the canopy into a constant maximum diameter during terminal descent for maximum drag and deceleration.
B. Kleihaus; J. Kunz
2000-12-20T23:59:59.000Z
We construct stationary black holes in SU(2) Einstein-Yang-Mills theory, which carry angular momentum and electric charge. Possessing non-trivial non-abelian magnetic fields outside their regular event horizon, they represent non-perturbative rotating hairy black holes.
LABORATORY VI ROTATIONAL DYNAMICS
Minnesota, University of
Lab VI - 1 LABORATORY VI ROTATIONAL DYNAMICS So far this semester, you have been asked to think kinematics. OBJECTIVES: Successfully completing this laboratory should enable you to: · Use linear kinematics in a laboratory on earth, before launching the satellite. EQUIPMENT You will use an apparatus that spins
FORMULATION OF ROTATIONAL SYSTEMS
, by formulating a rotational equivalent mass called "moment of inertia." 3.1 Newton's Law Revisited Let us begin Figure 3.2: Simple Pendulum with Torsion Spring for T to obtain Newton's law in units of torque: T = (mr2 gravitational term as the crude analysis of Section ??, but now we know the magnitude of the terms we have
Paul C. W. Davies; Tevian Dray; Corinne A. Manogue
1996-01-22T23:59:59.000Z
We derive conditions for rotating particle detectors to respond in a variety of bounded spacetimes and compare the results with the folklore that particle detectors do not respond in the vacuum state appropriate to their motion. Applications involving possible violations of the second law of thermodynamics are briefly addressed.
Deveney, J.E.; Sanderson, S.N.
1981-10-27T23:59:59.000Z
A valve stem and lock is disclosed which includes a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.
Clinical Rotation Descriptions-2013 Clinical Rotation Description Forms the Student
Sheridan, Jennifer
Clinical Rotation Descriptions- 2013 Clinical Rotation Description Forms the Student Completes:1 with a PT 2 from rotation (3), allowing the PT 2 to teach the PT 1. GAs * at end of experience, Clinical Performance Evaluation, Physical Therapy Student Evaluation: Clinical Experience and Instruction 1 page form
Kassianov, Evgueni I.; Flynn, Connor J.; Ackerman, Thomas P.; Barnard, James C.
2007-06-15T23:59:59.000Z
Multi-filter Rotating Shadowband Radiometers (MFRSRs) provide routine measurements of the aerosol optical depth ( << OLE Object: Microsoft Equation 3.0 >> ) at six wavelengths (0.415, 0.5, 0.615, 0.673, 0.870 and 0.94 << OLE Object: Picture (Metafile) >> ). The single-scattering albedo ( << OLE Object: Microsoft Equation 3.0 >> ) is typically estimated from the MFRSR measurements by assuming the asymmetry parameter ( << OLE Object: Microsoft Equation 3.0 >> ). In most instances, however, it is not easy to set an appropriate value of << OLE Object: Microsoft Equation 3.0 >> due to its strong temporal and spatial variability. Here, we introduce and validate an updated version of our retrieval technique that allows one to estimate simultaneously << OLE Object: Microsoft Equation 3.0 >> and << OLE Object: Microsoft Equation 3.0 >> for different types of aerosol. We use the aerosol and radiative properties obtained during the Atmospheric Science Program (ARM) Aerosol Intensive Operational Period (IOP) to validate our retrieval in two ways. First, the MFRSR-retrieved optical properties are compared with those obtained from independent surface, Aerosol Robotic Network (AERONET) and aircraft measurements. The MFRSR-retrieved optical properties are in reasonable agreement with these independent measurements. Second, we perform radiative closure experiments using the MFRSR-retrieved optical properties. The calculated broadband values of the direct and diffuse fluxes are comparable (~ 5 << OLE Object: Microsoft Equation 3.0 >> ) to those obtained from measurements.
Digital rotation measurement unit
Sanderson, S.N.
1983-09-30T23:59:59.000Z
A digital rotation indicator is disclosed for monitoring the position of a valve member having a movable actuator. The indicator utilizes mercury switches adapted to move in cooperation with the actuator. Each of the switches produces an output as it changes state when the actuator moves. A direction detection circuit is connected to the switches to produce a first digital signal indicative of the direction of rotation of the actuator. A count pulse generating circuit is also connected to the switches to produce a second digital pulse signal having count pulses corresponding to a change of state of any of the mercury switches. A reset pulse generating circuit is provided to generate a reset pulse each time a count pulse is generated. An up/down counter is connected to receive the first digital pulse signal and the second digital pulse signal and to count the pulses of the second digital pulse signal either up or down depending upon the instantaneous digital value of the first digital signal whereby a running count indicative of the movement of the actuator is maintained.
Anson, Donald (Worthington, OH)
1990-01-01T23:59:59.000Z
A perforated drum (10) rotates in a coaxial cylindrical housing (18) having three circumferential ports (19,22,23), and an axial outlet (24) at one end. The axis (11) is horizontal. A fibrous filter medium (20) is fed through a port (19) on or near the top of the housing (81) by a distributing mechanism (36) which lays a uniform mat (26) of the desired thickness onto the rotating drum (10). This mat (26) is carried by the drum (10) to a second port (23) through which dirty fluid (13) enters. The fluid (13) passes through the filter (26) and the cleaned stream (16) exits through the open end (15) of the drum (10) and the axial port (24) in the housing (18). The dirty filter material (20) is carried on to a third port (22) near the bottom of the housing (18) and drops into a receiver (31) from which it is continuously removed, cleaned (30), and returned (32) to the charging port (36) at the top. To support the filter mat, the perforated cylinder may carry a series of tines (40), shaped blades (41), or pockets, so that the mat (26) will not fall from the drum (10) prematurely. To minimize risk of mat failure, the fluid inlet port (23) may be located above the horizontal centerline (11).
Kepler rapidly rotating giant stars
Costa, A D; Bravo, J P; Paz-Chinchón, F; Chagas, M L das; Leão, I C; de Oliveira, G Pereira; da Silva, R Rodrigues; Roque, S; de Oliveira, L L A; da Silva, D Freire; De Medeiros, J R
2015-01-01T23:59:59.000Z
Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of sub-stellar companions by their hosting stars. In the present letter we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting very short rotation period with values ranging from 13 to 55 days. This finding points for remarkable surface rotation rates, up to 18 times the Sun rotation. These giants are combined with 6 other recently listed in the literature for mid-IR diagnostic based on WISE information, from which a trend for an infrared excess is revealed for at least a half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.
Rotational Instabilities and Centrifugal Hangup
Kimberly C. B. New; Joan M. Centrella
2001-01-17T23:59:59.000Z
One interesting class of gravitational radiation sources includes rapidly rotating astrophysical objects that encounter dynamical instabilities. We have carried out a set of simulations of rotationally induced instabilities in differentially rotating polytropes. An $n$=1.5 polytrope with the Maclaurin rotation law will encounter the $m$=2 bar instability at $T/|W| \\gtrsim 0.27$. Our results indicate that the remnant of this instability is a persistent bar-like structure that emits a long-lived gravitational radiation signal. Furthermore, dynamical instability is shown to occur in $n$=3.33 polytropes with the $j$-constant rotation law at $T/|W| \\gtrsim 0.14$. In this case, the dominant mode of instability is $m$=1. Such instability may allow a centrifugally-hung core to begin collapsing to neutron star densities on a dynamical timescale. If it occurs in a supermassive star, it may produce gravitational radiation detectable by LISA.
Cooling system for rotating machine
Gerstler, William Dwight (Niskayuna, NY); El-Refaie, Ayman Mohamed Fawzi (Niskayuna, NY); Lokhandwalla, Murtuza (Clifton Park, NY); Alexander, James Pellegrino (Ballston Lake, NY); Quirion, Owen Scott (Clifton Park, NY); Palafox, Pepe (Schenectady, NY); Shen, Xiaochun (Schenectady, NY); Salasoo, Lembit (Schenectady, NY)
2011-08-09T23:59:59.000Z
An electrical machine comprising a rotor is presented. The electrical machine includes the rotor disposed on a rotatable shaft and defining a plurality of radial protrusions extending from the shaft up to a periphery of the rotor. The radial protrusions having cavities define a fluid path. A stationary shaft is disposed concentrically within the rotatable shaft wherein an annular space is formed between the stationary and rotatable shaft. A plurality of magnetic segments is disposed on the radial protrusions and the fluid path from within the stationary shaft into the annular space and extending through the cavities within the radial protrusions.
Rotational dynamics of entangled polymers
Jean-Charles Walter; Michiel Laleman; Marco Baiesi; Enrico Carlon
2014-09-01T23:59:59.000Z
Some recent results on the rotational dynamics of polymers are reviewed and extended. We focus here on the relaxation of a polymer, either flexible or semiflexible, initially wrapped around a rigid rod. We also study the steady polymer rotation generated by a constant torque on the rod. The interplay of frictional and entropic forces leads to a complex dynamical behavior characterized by non-trivial universal exponents. The results are based on extensive simulations of polymers undergoing Rouse dynamics and on an analytical approach using force balance and scaling arguments. The analytical results are in general in good agreement with the simulations, showing how a simplified approach can correctly capture the complex dynamical behavior of rotating polymers.
Vacuum friction in rotating particles
A. Manjavacas; F. J. García de Abajo
2010-09-21T23:59:59.000Z
We study the frictional torque acting on particles rotating in empty space. At zero temperature, vacuum friction transforms mechanical energy into light emission and produces particle heating. However, particle cooling relative to the environment occurs at finite temperatures and low rotation velocities. Radiation emission is boosted and its spectrum significantly departed from a hot-body emission profile as the velocity increases. Stopping times ranging from hours to billions of years are predicted for materials, particle sizes, and temperatures accessible to experiment. Implications for the behavior of cosmic dust are discussed.
Rotating drum variable depth sampler
Nance, Thomas A. (Aiken, SC); Steeper, Timothy J. (Trenton, SC)
2008-07-01T23:59:59.000Z
A sampling device for collecting depth-specific samples in silt, sludge and granular media has three chambers separated by a pair of iris valves. Rotation of the middle chamber closes the valves and isolates a sample in a middle chamber.
Rotationally invariant multilevel block codes
Kulandaivelu, Anita
1993-01-01T23:59:59.000Z
The objective of this thesis is to evaluate the performance of block codes that are designed to be rotationally invariant, in a multilevel coding scheme, over a channel modelled to be white gaussian noise. Also, the use of non-binary codes...
Rotationally invariant multilevel block codes
Kulandaivelu, Anita
1993-01-01T23:59:59.000Z
The objective of this thesis is to evaluate the performance of block codes that are designed to be rotationally invariant, in a multilevel coding scheme, over a channel modelled to be white gaussian noise. Also, the use of non-binary codes...
Wave-Driven Rotation In Centrifugal Mirrors
Abraham J. Fetterman and Nathaniel J. Fisch
2011-03-28T23:59:59.000Z
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.
Impact of plasma poloidal rotation on resistive wall mode instability in toroidally rotating plasmas
Aiba, N.; Shiraishi, J. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Tokuda, S. [Research Organization for Information Science and Technology, Kita-Shinagawa, Shinagawa, Tokyo 140-0001 (Japan)
2011-02-15T23:59:59.000Z
Stability of resistive wall mode (RWM) is investigated in a cylindrical plasma and an axisymmetric toroidal plasma by taking into account not only toroidal rotation but also poloidal rotation. Since the Doppler shifted frequency is responsible for the RWM stability, the modification of this Doppler shifted frequency by poloidal rotation affects the rotation effect on RWM. When a poloidal rotation frequency is not so large, the effect of poloidal rotation on the RWM stability can be approximately treated with the modified toroidal rotation frequency. In a toroidal plasma, this modified frequency is determined by subtracting a toroidal component of the rotation parallel to the magnetic field from the toroidal rotation frequency. The poloidal rotation that counteracts the effect of the Doppler shift strongly reduces the stabilizing effect of toroidal rotation, but by changing the rotational direction, the poloidal rotation enhances this stabilizing effect. This trend is confirmed in not only a cylindrical plasma but also a toroidal plasma. This result indicates that poloidal rotation produces the dependence of the critical toroidal rotation frequency for stabilizing RWM on the rotational direction of toroidal rotation in the same magnetic configuration.
Rotation generation and transport in tokamak plasmas
Podpaly, Yuri Anatoly
2012-01-01T23:59:59.000Z
Plasma toroidal rotation is a factor important for plasma stability and transport, but it is still a fairly poorly understood area of physics. This thesis focuses on three aspects of rotation: momentum transport, Ohmic ...
Consider Steam Turbine Drives for Rotating Equipment | Department...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Steam Turbine Drives for Rotating Equipment Consider Steam Turbine Drives for Rotating Equipment This tip sheet outlines the benefits of steam turbine drives for rotating equipment...
Gravity controlled anti-reverse rotation device
Dickinson, Robert J. (Shaler Township, Allegheny County, PA); Wetherill, Todd M. (Lower Burrell, PA)
1983-01-01T23:59:59.000Z
A gravity assisted anti-reverse rotation device for preventing reverse rotation of pumps and the like. A horizontally mounted pawl is disposed to mesh with a fixed ratchet preventing reverse rotation when the pawl is advanced into intercourse with the ratchet by a vertically mounted lever having a lumped mass. Gravitation action on the lumped mass urges the pawl into mesh with the ratchet, while centrifugal force on the lumped mass during forward, allowed rotation retracts the pawl away from the ratchet.
Rotating concave eddy current probe
Roach, Dennis P. (Albuquerque, NM); Walkington, Phil (Albuquerque, NM); Rackow, Kirk A. (Albuquerque, NM); Hohman, Ed (Albuquerque, NM)
2008-04-01T23:59:59.000Z
A rotating concave eddy current probe for detecting fatigue cracks hidden from view underneath the head of a raised head fastener, such as a buttonhead-type rivet, used to join together structural skins, such as aluminum aircraft skins. The probe has a recessed concave dimple in its bottom surface that closely conforms to the shape of the raised head. The concave dimple holds the probe in good alignment on top of the rivet while the probe is rotated around the rivet's centerline. One or more magnetic coils are rigidly embedded within the probe's cylindrical body, which is made of a non-conducting material. This design overcomes the inspection impediment associated with widely varying conductivity in fastened joints.
Nuclear rotation in the continuum
Fossez, K; Jaganathen, Y; Michel, N; P?oszajczak, M
2015-01-01T23:59:59.000Z
Atomic nuclei often exhibit collective rotational-like behavior in highly excited states, well above the particle emission threshold. What determines the existence of collective motion in the continuum region, is not fully understood. In this work, by studying the collective rotation of the positive-parity deformed configurations of the one-neutron halo nucleus $^{11}$Be, we assess different mechanisms that stabilize collective behavior beyond the limits of particle stability. To solve a particle-plus-core problem, we employ a coupled-channel formalism and the Berggren single-particle ensemble, which explicitly contains bound states, narrow resonances, and the scattering space. We study the valence-neutron density in the intrinsic rotor frame to assess the validity of the adiabatic approach as the excitation energy increases. We demonstrate that collective rotation of the ground band of $^{11}$Be is stabilized by (i) the fact that the $\\ell=0$ one-neutron decay channel is closed, and (ii) the angular momentum...
Collective rotation from ab initio theory
M. A. Caprio; P. Maris; J. P. Vary; R. Smith
2015-09-01T23:59:59.000Z
Through ab initio approaches in nuclear theory, we may now seek to quantitatively understand the wealth of nuclear collective phenomena starting from the underlying internucleon interactions. No-core configuration interaction (NCCI) calculations for p-shell nuclei give rise to rotational bands, as evidenced by rotational patterns for excitation energies, electromagnetic moments, and electromagnetic transitions. In this review, NCCI calculations of 7-9Be are used to illustrate and explore ab initio rotational structure, and the resulting predictions for rotational band properties are compared with experiment. We highlight the robustness of ab initio rotational predictions across different choices for the internucleon interaction.
Trirotron: triode rotating beam radio frequency amplifier
Lebacqz, Jean V. (Stanford, CA)
1980-01-01T23:59:59.000Z
High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rotating field to thereby produce a high-power output at the frequency of the rotating field.
Kassianov, Evgueni I.; Barnard, James C.; Flynn, Connor J.; Riihimaki, Laura D.; Michalsky, Joseph; Hodges, G. B.
2014-10-25T23:59:59.000Z
We introduce and evaluate a simple retrieval of areal-averaged surface albedo using ground-based measurements of atmospheric transmission alone at five wavelengths (415, 500, 615, 673 and 870nm), under fully overcast conditions. Our retrieval is based on a one-line semi-analytical equation and widely accepted assumptions regarding the weak spectral dependence of cloud optical properties, such as cloud optical depth and asymmetry parameter, in the visible and near-infrared spectral range. To illustrate the performance of our retrieval, we use as input measurements of spectral atmospheric transmission from Multi-Filter Rotating Shadowband Radiometer (MFRSR). These MFRSR data are collected at two well-established continental sites in the United States supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program and National Oceanic and Atmospheric Administration (NOAA). The areal-averaged albedos obtained from the MFRSR are compared with collocated and coincident Moderate Resolution Imaging Spectroradiometer (MODIS) white-sky albedo. In particular, these comparisons are made at four MFRSR wavelengths (500, 615, 673 and 870nm) and for four seasons (winter, spring, summer and fall) at the ARM site using multi-year (2008-2013) MFRSR and MODIS data. Good agreement, on average, for these wavelengths results in small values (?0.01) of the corresponding root mean square errors (RMSEs) for these two sites. The obtained RMSEs are comparable with those obtained previously for the shortwave albedos (MODIS-derived versus tower-measured) for these sites during growing seasons. We also demonstrate good agreement between tower-based daily-averaged surface albedos measured for “nearby” overcast and non-overcast days. Thus, our retrieval originally developed for overcast conditions likely can be extended for non-overcast days by interpolating between overcast retrievals.
Kassianov, Evgueni I.; Barnard, James C.; Flynn, Connor J.; Riihimaki, Laura D.; Michalsky, Joseph; Hodges, G. B.
2014-08-22T23:59:59.000Z
We present here a simple retrieval of the areal-averaged and spectrally resolved surface albedo using only ground-based measurements of atmospheric transmission under fully overcast conditions. Our retrieval is based on a one-line equation and widely accepted assumptions regarding the weak spectral dependence of cloud optical properties in the visible and near-infrared spectral range. The feasibility of our approach for the routine determinations of albedo is demonstrated for different landscapes with various degrees of heterogeneity using three sets of measurements:(1) spectrally resolved atmospheric transmission from Multi-Filter Rotating Shadowband Radiometer (MFRSR) at wavelength 415, 500, 615, 673, and 870 nm, (2) tower-based measurements of local surface albedo at the same wavelengths, and (3) areal-averaged surface albedo at four wavelengths (470, 560, 670 and 860 nm) from collocated and coincident Moderate Resolution Imaging Spectroradiometer (MODIS) observations. These integrated datasets cover both long (2008-2013) and short (April-May, 2010) periods at the ARM Southern Great Plains (SGP) site and the NOAA Table Mountain site, respectively. The calculated root mean square error (RMSE), which is defined here as the root mean squared difference between the MODIS-derived surface albedo and the retrieved area-averaged albedo, is quite small (RMSE?0.01) and comparable with that obtained previously by other investigators for the shortwave broadband albedo. Good agreement between the tower-based daily averages of surface albedo for the completely overcast and non-overcast conditions is also demonstrated. This agreement suggests that our retrieval originally developed for the overcast conditions likely will work for non-overcast conditions as well.
Contained Modes In Mirrors With Sheared Rotation
Abraham J. Fetterman and Nathaniel J. Fisch
2010-10-08T23:59:59.000Z
In mirrors with E × B rotation, a fixed azimuthal perturbation in the lab frame can appear as a wave in the rotating frame. If the rotation frequency varies with radius, the plasma-frame wave frequency will also vary radially due to the Doppler shift. A wave that propagates in the high rotation plasma region might therefore be evanescent at the plasma edge. This can lead to radially localized Alfven eigenmodes with high azimuthal mode numbers. Contained Alfven modes are found both for peaked and non-peaked rotation profiles. These modes might be useful for alpha channeling or ion heating, as the high azimuthal wave number allows the plasma wave frequency in the rotating frame to exceed the ion cyclotron frequency. __________________________________________________
Inertial measurement unit using rotatable MEMS sensors
Kohler, Stewart M.; Allen, James J.
2006-06-27T23:59:59.000Z
A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator for drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows, for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.
Inertial measurement unit using rotatable MEMS sensors
Kohler, Stewart M. (Albuquerque, NM); Allen, James J. (Albuquerque, NM)
2007-05-01T23:59:59.000Z
A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.
Fragmentation in rotating isothermal protostellar clouds
Bodenheimer, P.; Tohline, J.E.; Black, D.C.
1980-01-01T23:59:59.000Z
Results of an extensive set of 3-D hydrodynamic calculations that have been performed to investigate the susceptibility of rotating clouds to gravitational fragmentation are presented. (GHT)
Control of molecular rotation in the limit of extreme rotational excitation
Milner, V
2015-01-01T23:59:59.000Z
Laser control of molecular rotation is an area of active research. A number of recent studies has aimed at expanding the reach of rotational control to extreme, previously inaccessible rotational states, as well as controlling the directionality of molecular rotation. Dense ensembles of molecules undergoing ultrafast uni-directional rotation, known as molecular superrotors, are anticipated to exhibit unique properties, from spatially anisotropic diffusion and vortex formation to the creation of powerful acoustic waves and tuneable THz radiation. Here we describe our recent progress in controlling molecular rotation in the regime of high rotational excitation. We review two experimental techniques of producing uni-directional rotational wave packets with a "chiral train" of femtosecond pulses and an "optical centrifuge". Three complementary detection methods, enabling the direct observation, characterization and control of the superrotor states, are outlined: the one based on coherent Raman scattering, and two...
7. Flows in a rotating reference frame 7.1. Rotating reference frames
Read, Peter L.
in a rotating reference frame. We use rotating axes, fixed w.r.t. the rotating system but note that time-derivatives of vectors must be modified: 1 #12;Suppose frame R rotates at constant angular velocity = (0, 0, ) w.r.t. an inertial frame I. Consider vector A(t) Â suppose for simplicity that it lies in the xy-plane of R and I
Experimental and analytical study of rotating cavitation
Kamijo, Kenjiro; Shimura, Takashi; Tsujimoto, Yoshinobu [National Aerospace Lab., Miyagi (Japan). Kakuda Research Center
1994-12-31T23:59:59.000Z
This paper describes experimental and analytical results of rotating cavitation. There are four major sections in this paper. The first section presents the main characteristics of rotating cavitation which was found in the inducer test using a water tunnel. The second section describes the rotating cavitation which occurred in the development test of an LE-7 liquid oxygen pump for the H-II rocket. Also described in this section is how the rotating cavitation was suppressed. The rotating cavitation was the cause of both super synchronous shaft vibration and an unstable head coefficient curve. The third section presents how the theory of rotating cavitation was developed. The final section shows the measured cavitation compliance and mass flow gain factor of the LE-7 pump inducer for comparison of the experimental and analytical results of the rotating cavitation of the LE-7 pump inducer. Almost all the information presented in this paper has already been reported by Kamijo et al. (1977, 1980, 1993, 1993) and by Shimura (1993). In the present paper, the authors attempt to combine and give a clear overview of the experimental and analytical results described in the previous papers to systematically show their experience and findings on rotating cavitation.
Holographic Superconductors in a Rotating Spacetime
Kai Lin; Elcio Abdalla
2014-10-17T23:59:59.000Z
We consider holographic superconductors in a rotating black string spacetime. In view of the mandatory introduction of the $A_\\varphi$ component of the vector potential we are left with three equations to be solved. Their solutions show that the effect of the rotating parameter $a$ influences the critical temperature $T_c$ and the conductivity $\\sigma$ in a simple but not trivial way.
Computational Methods for High-Dimensional Rotations
Buja, Andreas
. To be useful, virtual rotations need to be under interactive user control, and they need to be animated. We scatters in virtual 3-D space. Although not obvivous, three-dimensional data rotations can be extended is due to the power of human 3-D perception and the natural controls they afford. To perform 3-D
Injectivity of Rotation Invariant Windowed Radon Transforms
Biermé, Hermine
Injectivity of Rotation Invariant Windowed Radon Transforms Hermine Bierm´e MAPMO-UMR 6628, D rotation invariant windowed Radon transforms that integrate a func- tion over hyperplanes by using a radial with positive real part , the windowed Radon transform is not injective on functions with a Gaussian decay
Spontaneous generation of rotation in tokamak plasmas
Parra Diaz, Felix [Oxford University] [Oxford University
2013-12-24T23:59:59.000Z
Three different aspects of intrinsic rotation have been treated. i) A new, first principles model for intrinsic rotation [F.I. Parra, M. Barnes and P.J. Catto, Nucl. Fusion 51, 113001 (2011)] has been implemented in the gyrokinetic code GS2. The results obtained with the code are consistent with several experimental observations, namely the rotation peaking observed after an L-H transition, the rotation reversal observed in Ohmic plasmas, and the change in rotation that follows Lower Hybrid wave injection. ii) The model in [F.I. Parra, M. Barnes and P.J. Catto, Nucl. Fusion 51, 113001 (2011)] has several simplifying assumptions that seem to be satisfied in most tokamaks. To check the importance of these hypotheses, first principles equations that do not rely on these simplifying assumptions have been derived, and a version of these new equations has been implemented in GS2 as well. iii) A tokamak cross-section that drives large intrinsic rotation has been proposed for future large tokamaks. In large tokamaks, intrinsic rotation is expected to be very small unless some up-down asymmetry is introduced. The research conducted under this contract indicates that tilted ellipticity is the most efficient way to drive intrinsic rotation.
FIRST YEAR CLINIC ROTATIONS Inpatient unit
Chapman, Michael S.
FIRST YEAR CLINIC ROTATIONS Inpatient unit The fellow is responsible for the care and supervision weekly. Pediatric Hematology-Oncology Clinic The fellow on the PHO clinic rotation will be scheduled to evaluate scheduled clinic and infusion center patients along with an attending provider. Patients seen
Flow Split Venturi, Axially-Rotated Valve
Walrath, David E. (Laramie, WY); Lindberg, William R. (Laramie, WY); Burgess, Robert K. (Sheridan, WY); LaBelle, James (Murrieta, CA)
2000-02-22T23:59:59.000Z
The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop (characterized by a lower loss coefficient) by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. Similarly, the valve is designed, in some embodiments, to produce streamlined flow within the valve. An axially aligned outlet may also increase the flow efficiency. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal wide radius elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane. A seal separator may increase the useful life of the seal between the fixed and rotatable portions.
Generalization of rotational mechanics and application to aerospace systems
Sinclair, Andrew James
2005-08-29T23:59:59.000Z
-DIMENSIONAL PRINCIPAL ROTATIONS 5 A.Introduction.......................... 5 B. Review of N-DimensionalRotations............. 6 1. RotationMatrix ..................... 6 2. PrincipalRotationMatrices............... 9 3. ExtendedRodriguesParameters ............ 10 4... of the eight solutions for N =4: f- flip, s - swap, fs - flip and swap. ..................... 50 3 Relationships between four of the sixteen solutions for N =5: fr - flip-rotate, rf - rotate-flip, ff - flip-flip. ................. 54 4 Planar rigid body...
High-Performance Refrigerator Using Novel Rotating Heat Exchanger...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Using Novel Rotating Heat Exchanger Rotating heat exchangers installed in appliances and heat pumps have the potentially to reduce energy costs and refrigerant charge in a compact...
Rotational Rehybridization and the High Temperature Phase of...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Rotational Rehybridization and the High Temperature Phase of UC2. Rotational Rehybridization and the High Temperature Phase of UC2. Abstract: The screened hybrid approximation...
ROTATIONAL DOPPLER BEAMING IN ECLIPSING BINARIES
Groot, Paul J., E-mail: pgroot@astro.ru.nl [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
2012-01-20T23:59:59.000Z
In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analog of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high-quality photometric light curves and can be used to determine stellar obliquities as well as, e.g., an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.
Title of dissertation: ROTATING, HYDROMAGNETIC LABORATORY EXPERIMENT
Lathrop, Daniel P.
ABSTRACT Title of dissertation: ROTATING, HYDROMAGNETIC LABORATORY EXPERIMENT MODELLING PLANETARY CORES Douglas H. Kelley, Doctor of Philosophy, 2009 Dissertation directed by: Professor Daniel P. Lathrop Department of Physics This dissertation describes a series of laboratory experiments motivated
Rotational hysteresis of exchange-spring magnets.
Jiang, J.S.; Bader, S.D.; Kaper, H.; Leaf, G.K.; Shull, R.D.; Shapiro, A.J.; Gornakov, V.S.; Nikitenko, V.I.; Platt, C.L.; Berkowitz, A.E.; David, S.; Fullerton, E.E.
2002-03-27T23:59:59.000Z
We highlight our experimental studies and micromagnetic simulations of the rotational hysteresis in exchange-spring magnets. Magneto-optical imaging and torque magnetometry measurements for SmCo/Fe exchange-spring films with uniaxial in-plane anisotropy show that the magnetization rotation created in the magnetically soft Fe layer by a rotating magnetic field is hysteretic. The rotational hysteresis is due to the reversal of the chirality of the spin spiral structure. Micromagnetic simulations reveal two reversal modes of the chirality, one at low fields due to an in-plane untwisting of the spiral, and the other, at high fields, due to an out-of-plane fanning of the spiral.
Galactic Rotation and Large Scale Structures
B. G. Sidharth
1999-04-05T23:59:59.000Z
On the basis of a recent cosmological model, the puzzle of galactic rotational velocities at their edges is explained without invoking dark matter. A rationale for the existence of structures like galaxies and superclusters is also obtained.
SHORT ROTATION WOODY CROPS FACTSHEET SERIES # 5
Minnesota, University of
SHORT ROTATION WOODY CROPS FACTSHEET SERIES # 5 Sustainability of SRWC for Energy1 WHAT IS SUSTAINABILITY? Sustainability is meeting the needs of the present without compromising the ability of future" of sustainability: economics, environmental, and social. ENVIRONMENTAL SUSTAINABILITY Environmental sustainability
On obliquely magnetized and differentially rotating stars
Wei, Xing
2015-01-01T23:59:59.000Z
We investigate the interaction of differential rotation and a misaligned magnetic field. The incompressible magnetohydrodynamic equations are solved numerically for a free-decay problem. In the kinematic limit, differential rotation annihilates the non-axisymmetric field on a timescale proportional to the cube root of magnetic Reynolds number ($Rm$), as predicted by R\\"adler. Nonlinearly, the outcome depends upon the initial energy in the non-axisymmetric part of the field. Sufficiently weak fields approach axisymmetry as in the kinematic limit; some differential rotation survives across magnetic surfaces, at least on intermediate timescales. Stronger fields enforce uniform rotation and remain non-axisymmetric. The initial field strength that divides these two regimes does not follow the scaling $Rm^{-1/3}$ predicted by quasi-kinematic arguments, perhaps because our $Rm$ is never sufficiently large or because of reconnection. We discuss the possible relevance of these results to tidal synchronization and tida...
Consider Steam Turbine Drives for Rotating Equipment
Not Available
2006-01-01T23:59:59.000Z
This revised ITP tip sheet on steam turbine drives for rotating equipment provides how-to advice for improving the system using low-cost, proven practices and technologies.
Two-fluid-sourced rotating wormholes
Azreg-Aïnou, Mustapha
2015-01-01T23:59:59.000Z
We briefly discuss some of the known and new properties of rotating geometries that are relevant to this work. We generalize the analytical method of superposition of fields, known for generating nonrotating solutions, and apply it to construct massless and massive rotating physical wormholes sourced by a source-free electromagnetic field and an exotic fluid both anisotropic. Their stress-energy tensors are presented in compact and general forms. For the massive rotating wormholes there exists a mass-charge constraint yielding almost no more dragging effects than ordinary stars. There are conical spirals through the throat along which the null and weak energy conditions are not violated for these rotating wormholes. This conclusion extends to nonrotating massive type I wormholes derived previously by the author that seem to be the first kind of nonrotating wormholes with this property.
Two-fluid-sourced rotating wormholes
Mustapha Azreg-Aïnou
2015-05-06T23:59:59.000Z
We briefly discuss some of the known and new properties of rotating geometries that are relevant to this work. We generalize the analytical method of superposition of fields, known for generating nonrotating solutions, and apply it to construct massless and massive rotating physical wormholes sourced by a source-free electromagnetic field and an exotic fluid both anisotropic. Their stress-energy tensors are presented in compact and general forms. For the massive rotating wormholes there exists a mass-charge constraint yielding almost no more dragging effects than ordinary stars. There are conical spirals through the throat along which the null and weak energy conditions are not violated for these rotating wormholes. This conclusion extends to nonrotating massive type I wormholes derived previously by the author that seem to be the first kind of nonrotating wormholes with this property.
Collisional quenching of highly rotationally excited HF
Yang, Benhui; Forrey, R C; Stancil, P C; Balakrishnan, N
2015-01-01T23:59:59.000Z
Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Theoretical cross sections and rate coefficients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coefficient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coefficients for H and H$_2$ colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach. The calculation of state-to-state rotational quenching cross sections for HF due to He with initial rotational levels up to $j=20$ were performed for kinetic energies from 10$^{-5}$ to 15000...
Hydrogen atom in rotationally invariant noncommutative space
Kh. P. Gnatenko; V. M. Tkachuk
2014-11-03T23:59:59.000Z
We consider the noncommutative algebra which is rotationally invariant. The hydrogen atom is studied in a rotationally invariant noncommutative space. We find the corrections to the energy levels of the hydrogen atom up to the second order in the parameter of noncommutativity. The upper bound of the parameter of noncommutativity is estimated on the basis of the experimental results for 1s-2s transition frequency.
Wavelet Analysis of Galactic Rotation Curves
M. Kuassivi
2011-04-28T23:59:59.000Z
The spatial wavelet spectra of 73 published spiral galaxies's rotation curves are computed and their associated scaleograms are presented. Scaleograms are used to detect and isolate local features observed in spiral galaxies's rotation curves. Although wiggles and bumps are usually interpreted as signs of recent and on-going merging, the analysis of the scaleograms reveals regular patterns consistent with the presence of large-scale modes throughout the disk.
Rotation in an exact hydro model
L. P. Csernai; D. J. Wang; T. Csorgo
2014-07-07T23:59:59.000Z
We study an exact and extended solution of the fluid dynamical model of heavy ion reactions, and estimate the rate of slowing down of the rotation due to the longitudinal and transverse expansion of the system. The initial state parameters of the model are set on the basis of a realistic 3+1D fluid dynamical calculation at TeV energies, where the rotation is enhanced by the build up of the Kelvin Helmholtz Instability in the flow.
Split Venturi, Axially-Rotated Valve
Walrath, David E. (Laramie, WY); Lindberg, William R. (Laramie, WY); Burgess, Robert K. (Sheridan, WY)
2000-08-29T23:59:59.000Z
The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop (characterized by a lower loss coefficient) by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. Similarly, the valve is designed, in some embodiments, to produce streamlined flow within the valve. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal wide radius elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane.
Rotational properties of the Maria asteroid family
Kim, M.-J.; Byun, Y.-I. [Department of Astronomy, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, 120-749 Seoul (Korea, Republic of); Choi, Y.-J.; Moon, H.-K.; Hinse, T. C.; Park, J.-H. [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, 305-348 Daejeon (Korea, Republic of); Brosch, N. [Tel Aviv University, P.O. Box 39040, Tel Aviv 69978 (Israel); Kaplan, M.; Kaynar, S.; Uysal, Ö.; Eker, Z. [Akdeniz Universitesi, Fen Fakultesi, Dumlupinar Bulvari, Kampus, 07058 Antalya (Turkey); Güzel, E. [Department of Astronomy and Space Sciences, University of Ege, Bornova, 35100 Izmir (Turkey); Behrend, R. [Geneva Observatory, Rue de Vermont 37, 1202 Geneva (Switzerland); Yoon, J.-N. [Chungbuk National University Observatory, 802-3 Euntan-ri, Jincheon-gun, Chungcheongbuk-do (Korea, Republic of); Mottola, S.; Hellmich, S., E-mail: skarma@galaxy.yonsei.ac.kr [German Aerospace Center (DLR), Rutherfordstrasse 2, D-12489 Berlin (Germany)
2014-03-01T23:59:59.000Z
The Maria family is regarded as an old-type (?3 ± 1 Gyr) asteroid family that has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids to the inner solar system. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in the observed rotation rate distribution. The one-sample Kolmogorov-Smirnov test confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of light curves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a light-curve inversion method, we successfully determined the pole orientations for 13 Maria members and found an excess of prograde versus retrograde spins with a ratio (N{sub p} /N{sub r} ) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner solar system since the formation of the Maria family. We estimate that approximately 37-75 Maria family asteroids larger than 1 km have entered near-Earth space every 100 Myr.
AIAA 20023642 Effect of Rotation on Flow in a
Jacob, Jamey
AIAA 20023642 Effect of Rotation on Flow in a Ribbed Rotating Turbine Blade Cooling Duct Model Propulsion Conference AIAA-2002-3642 Effect of Rotation on Flow in a Ribbed Rotating Turbine Blade Cooling experiments in turbine blade cooling have fo- cused primarily on both simple and complex channel flow
Control of molecular rotation in the limit of extreme rotational excitation
V. Milner; J. W. Hepburn
2015-01-12T23:59:59.000Z
Laser control of molecular rotation is an area of active research. A number of recent studies has aimed at expanding the reach of rotational control to extreme, previously inaccessible rotational states, as well as controlling the directionality of molecular rotation. Dense ensembles of molecules undergoing ultrafast uni-directional rotation, known as molecular superrotors, are anticipated to exhibit unique properties, from spatially anisotropic diffusion and vortex formation to the creation of powerful acoustic waves and tuneable THz radiation. Here we describe our recent progress in controlling molecular rotation in the regime of high rotational excitation. We review two experimental techniques of producing uni-directional rotational wave packets with a "chiral train" of femtosecond pulses and an "optical centrifuge". Three complementary detection methods, enabling the direct observation, characterization and control of the superrotor states, are outlined: the one based on coherent Raman scattering, and two other methods employing both resonant and non-resonant multi-photon ionization. The capabilities of the described excitation and detection techniques are demonstrated with a few examples. The paper is concluded with an outlook for future developments.
Heart - Shaped Nuclei: Condensation of Rotational Aligned Octupole Phonons
S. Frauendorf
2007-10-24T23:59:59.000Z
The strong octupole correlations in the mass region $A\\approx 226$ are interpreted as rotation-induced condensation of octupole phonons having their angular momentum aligned with the rotational axis. Discrete phonon energy and parity conservation generate oscillations of the energy difference between the lowest rotational bands with positive and negative parity. Anharmonicities tend to synchronize the the rotation of the condensate and the quadrupole shape of the nucleus forming a rotating heart shape.
Controlling inertial focussing using rotational motion
Prohm, Christopher; Stark, Holger
2014-01-01T23:59:59.000Z
In inertial microfluidics lift forces cause a particle to migrate across streamlines to specific positions in the cross section of a microchannel. We control the rotational motion of a particle and demonstrate that this allows to manipulate the lift-force profile and thereby the particle's equilibrium positions. We perform two-dimensional simulation studies using the method of multi-particle collision dynamics. Particles with unconstrained rotational motion occupy stable equilibrium positions in both halfs of the channel while the center is unstable. When an external torque is applied to the particle, two equilibrium positions annihilate by passing a saddle-node bifurcation and only one stable fixpoint remains so that all particles move to one side of the channel. In contrast, non-rotating particles accumulate in the center and are pushed into one half of the channel when the angular velocity is fixed to a non-zero value.
Position, rotation, and intensity invariant recognizing method
Ochoa, Ellen (Pleasanton, CA); Schils, George F. (San Ramon, CA); Sweeney, Donald W. (Alamo, CA)
1989-01-01T23:59:59.000Z
A method for recognizing the presence of a particular target in a field of view which is target position, rotation, and intensity invariant includes the preparing of a target-specific invariant filter from a combination of all eigen-modes of a pattern of the particular target. Coherent radiation from the field of view is then imaged into an optical correlator in which the invariant filter is located. The invariant filter is rotated in the frequency plane of the optical correlator in order to produce a constant-amplitude rotational response in a correlation output plane when the particular target is present in the field of view. Any constant response is thus detected in the output The U.S. Government has rights in this invention pursuant to Contract No. DE-AC04-76DP00789 between the U.S. Department of Energy and AT&T Technologies, Inc.
Crop Rotations in the Brazos River Valley.
Whiteley, Eli L.; Hipp, Billy W.
1966-01-01T23:59:59.000Z
OF ROTATIONS ON SOIL PRODUCTIVITY AND PHYST- CAL PROPERTIES OF MILLER CLAY. First Second Third Fourth Rotation* year year year Year C Cr C, 0 C. 8-sc C, 0-sc, Sc C, A C, 0-a C, 0-a, A C, A-f, A-f C, C, A-f, A-f C, C, A-f, A-f Cr, Cr, A-f, A...-f Cr, Cr, A-f, A-f Cr, 0-sc, Sc Cotton Corn Cotton Cotton Cotton Cotton Cotton Cot ton Cotton Cotton Cotton Corn Corn Corn Continuous Continuous Oats Oats- sweetclover Oats- swee tclover Alfalfa Oats- alfalfa Oats- alfalfa...
Measuring deflections in a rotating shaft
Bailey, Edmond Ira
1968-01-01T23:59:59.000Z
MEASURING DEFLECTIONS IN A ROTATING SHAFT A Thesi s By EOMOND I RA BAILEY Submitted to the Graduate College of the Texas A8M University in qartial ful fillment of the requirements for the degree of MASTER OF SCIENCE January 1968 Major... Subject: MECHANICAL ENGINEERING MEASURING DEFLECTIONS IN A ROTATING SHAFT A Thesis By EDMOND IRA BAILEY Approved as to style and content by: Chairman of C ittee )Head of Department January 1968 /l, Member ACKNOWL E DGME NTS The author is most...
Measuring deflections in a rotating shaft
Bailey, Edmond Ira
1968-01-01T23:59:59.000Z
. Short range telemetry (4, 5) involves placing a frequency modulated transmitter on the rotating member and locating a receiver in close proximity such that the data may be trans fered from the rotat1ng member to the stationary readout. l Numbers... was insignificant. The above is the situation for which the measuring system was to be disigned. The accuracy desired for the measuring system was speci fied as + 5L' by Mr. Alexander (6) as needed for his research. The approximate critical speed of the shaft...
Vacuum coupling of rotating superconducting rotor
Shoykhet, Boris A.; Zhang, Burt Xudong; Driscoll, David Infante
2003-12-02T23:59:59.000Z
A rotating coupling allows a vacuum chamber in the rotor of a superconducting electric motor to be continually pumped out. The coupling consists of at least two concentric portions, one of which is allowed to rotate and the other of which is stationary. The coupling is located on the non-drive end of the rotor and is connected to a coolant supply and a vacuum pump. The coupling is smaller in diameter than the shaft of the rotor so that the shaft can be increased in diameter without having to increase the size of the vacuum seal.
A theoretical analysis of rotating cavitation in inducers
Tsujimoto, Y.; Kamijo, K. (National Aerospace Lab., Miyagi, (Japan)); Yoshida, Y. (Osaka Univ., Toyonaka, (Japan). Engineering Science)
1993-03-01T23:59:59.000Z
Rotating cavitation was analyzed using an actuator disk method. Quasi-steady pressure performance of the impeller, mass flow gain factor, and cavitation compliance of the cavity were taken into account. Three types of destabilizing modes were predicted: rotation cavitation propagating faster than the rotational speed of the impeller, rotating cavitation propagating in the direction opposite that of the impeller, and rotating stall propagating slower than the rotational speed of the impeller. It was shown that both types of rotating cavitation were caused by the positive mass flow gain factor, while the rotating stall was caused by the positive slope of the pressure performance. Stability and propagation velocity maps are presented for the two types of rotating cavitation in the mass flow gain factor-cavitation compliance place. The correlation between theoretical results and experimental observations is discussed.
Localization of fremions in rotating electromagnetic fields
B. V. Gisin
2015-06-15T23:59:59.000Z
Parameters of localization are defined in the lab and rotating frame for solutions of the Dirac equation in the field of a traveling circularly polarized electromagnetic wave and constant magnetic field. The radius of localization is of the order of the electromagnetic wavelength and lesser.
On rigidly rotating perfect fluid cylinders
B. V. Ivanov
2002-05-07T23:59:59.000Z
The gravitational field of a rigidly rotating perfect fluid cylinder with gamma- law equation of state is found analytically. The solution has two parameters and is physically realistic for gamma in the interval (1.41,2]. Closed timelike curves always appear at large distances.
Rigidly rotating cylinders of charged dust
B. V. Ivanov
2002-07-02T23:59:59.000Z
The gravitational field of a rigidly rotating cylinder of charged dust is found analytically. The general and all regular solutions are divided into three classes. The acceleration and the vorticity of the dust are given, as well as the conditions for the appearance of closed timelike curves.
Spectroscopic observation of the rotational Doppler effect
S. Barreiro; J. W. R. Tabosa; H. Failache; A. Lezama
2006-07-26T23:59:59.000Z
We report on the first spectroscopic observation of the rotational Doppler shift associated with light beams carrying orbital angular momentum. The effect is evidenced as the broadening of a Hanle/EIT coherence resonance on Rb vapor when the two incident Laguerre-Gaussian laser beams have opposite topological charges. The observations closely agree with theoretical predictions.
Convective heat transfer in rotating, circular channels
Hogan, Brenna Elizabeth
2012-01-01T23:59:59.000Z
Nusselt number values for flow in a rotating reference frame are obtained through computational fluid dynamic (CFD) analysis for Rossby numbers Ro ~1-4 and Reynolds numbers Re ~1,000-2,000. The heat-transfer model is first ...
(Revised May 22, 2012) Rotational Dynamics (Energy)
Collins, Gary S.
energy (the sum of kinetic and potential energies) to derive an expression for the moment of inertia that the expression for kinetic energy takes on this simple form. Experiment Set Up The apparatus consists of a Rotary. The rotating object has kinetic energy but we cannot write it in the familiar form ½mv2 because the velocities
Wave-particle Interactions In Rotating Mirrors
Abraham J. Fetterman and Nathaniel J. Fisch
2011-01-11T23:59:59.000Z
Wave-particle interactions in E×B rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation. Energy may also be transferred from the electric field to particles or waves, which may be useful for ion heating and energy generation.
Observation of Bloch oscillations in molecular rotation
Johannes Floß; Andrei Kamalov; Ilya Sh. Averbukh; Philip H. Bucksbaum
2015-04-26T23:59:59.000Z
The periodically kicked quantum rotor is known for non-classical effects such as quantum localisation in angular momentum space or quantum resonances in rotational excitation. These phenomena have been studied in diverse systems mimicking the kicked rotor, such as cold atoms in optical lattices, or coupled photonic structures. Recently, it was predicted that several solid state quantum localisation phenomena - Anderson localisation, Bloch oscillations, and Tamm-Shockley surface states - may manifest themselves in the rotational dynamics of laser-kicked molecules. Here, we report the first observation of rotational Bloch oscillations in a gas of nitrogen molecules kicked by a periodic train of femtosecond laser pulses. A controllable detuning from the quantum resonance creates an effective accelerating potential in angular momentum space, inducing Bloch-like oscillations of the rotational excitation. These oscillations are measured via the temporal modulation of the refractive index of the gas. Our results introduce room-temperature laser-kicked molecules as a new laboratory for studies of localisation phenomena in quantum transport.
Rotation in a Generalised Dirac's Universe
Marcelo Samuel Berman
2008-10-27T23:59:59.000Z
The extension of Dirac's LNH to cover cosmological and fine-structure time-varying "constants", and the rotation of the Universe, is here analysed, including a "derivation" of the angular speed of the present Universe, and of the inflationary phase. Criticizable points on the present calculation, are clarified.
Pressure Gain Combustion Rotating Detonation Engines (RDE)
Pressure Gain Combustion Rotating Detonation Engines (RDE) Dr. Chris Brophy, David Dausen, Lee Van Houtte Students LT Culwell, ENS Khol, Robert Wright, Andrew Chaves Rocket Propulsion & Combustion Lab-based combustion to extract increase thermodynamic cycle efficiency for work/thrust apps. · Higher Enthalpy
Quantum Vacuum Instability Near Rotating Stars
A L Matacz; A C Ottewill; P C W Davies
1992-12-08T23:59:59.000Z
We discuss the Starobinskii-Unruh process for the Kerr black hole. We show how this effect is related to the theory of squeezed states. We then consider a simple model for a highly relativistic rotating star and show that the Starobinskii-Unruh effect is absent.
STEPS IN SLOW FLAGELLAR MOTOR ROTATION
Leake, Mark C.
STEPS IN SLOW FLAGELLAR MOTOR ROTATION Alexander D. Rowe1 , Yoshiyuki Sowa2, Mark C. Leake1+ -specific motors. Torque is generated by the interaction between stator complexes and FliG proteins revolution. CHIMERIC MOTOR: The stator units comprising the flagellar motors of the YS34 strain - used
Excitation system for rotating synchronous machines
Umans, Stephen D. (Belmont, MA); Driscoll, David J. (South Euclid, OH)
2002-01-01T23:59:59.000Z
A system for providing DC current to a rotating superconducting winding is provided. The system receives current feedback from the superconducting winding and determines an error signal based on the current feedback and a reference signal. The system determines a control signal corresponding to the error signal and provides a positive and negative superconducting winding excitation voltage based on the control signal.
Film cooling effectiveness measurements on rotating and non-rotating turbine components
Ahn, Jaeyong
2007-04-25T23:59:59.000Z
Detailed film cooling effectiveness distributions were measured on the stationary blade tip and on the leading edge region of a rotating blade using a Pressure Sensitive Paint technique. Air and nitrogen gas were used as the film cooling gases...
Film cooling effectiveness measurements on rotating and non-rotating turbine components
Ahn, Jaeyong
2007-04-25T23:59:59.000Z
Detailed film cooling effectiveness distributions were measured on the stationary blade tip and on the leading edge region of a rotating blade using a Pressure Sensitive Paint technique. Air and nitrogen gas were used as the film cooling gases...
Gordon, Kenneth A. (Kenneth Andrew), 1970-
1999-01-01T23:59:59.000Z
The effects of two types of flow nonuniformity on stall inception behavior were assessed with linearized stability analyses of two compressor flow models. Response to rotating tip clearance asymmetries induced by a whirling ...
D. E. Alvarez-Castillo; C. B. Compean; M. Kirchbach
2011-05-06T23:59:59.000Z
We predict level degeneracy of the rotational type in diatomic molecules described by means of a cotangent-hindered rigid rotator. The problem is shown to be exactly solvable in terms of non-classical Romanovski polynomials. The energies of such a system are linear combinations of t(t+1) and 1/[t(t+1)+1/4] terms with the non-negative integer principal quantum number t=n+|/bar{m}| being the sum of the degree n of the polynomials and the absolute value, |/bar{m}|, of the square root of the separation constant between the polar and azimuthal motions. The latter obeys, with respect to t, the same branching rule, |/bar{m}|=0,1,..., t, as does the magnetic quantum number with respect to the angular momentum, l, and, in this fashion, the t quantum number presents itself indistinguishable from l. In effect, the spectrum of the hindered rotator has the same (2t+1)-fold level multiplicity as the unperturbed one. For small t values, the wave functions and excitation energies of the perturbed rotator differ from the ordinary spherical harmonics, and the l(l+1) law, respectively, while approaching them asymptotically with increasing t. In this fashion the breaking of the rotational symmetry at the level of the representation functions is opaqued by the level degeneracy. The model provides a tool for the description of rotational bands with anomalously large gaps between the ground state and its first excitation.
Simplified algorithms for calculating double-couple rotation
Kagan, Yan Y.
2007-01-01T23:59:59.000Z
Table 3 shows axis dot products, the rotation angles, and coordinatesand coordinates of rotation poles for several earthquake pairs from Tableof Table 3 would coincide with the b -axis (its coordinates
Centrifugally activated bearing for high-speed rotating machinery
Post, Richard F. (Walnut Creek, CA)
1994-01-01T23:59:59.000Z
A centrifugally activated bearing is disclosed. The bearing includes an annular member that extends laterally and radially from a central axis. A rotating member that rotates about the central axis relative to the annular member is also included. The rotating member has an interior chamber that surrounds the central axis and in which the annular member is suspended. Furthermore, the interior chamber has a concave shape for retaining a lubricant therein while the rotating member is at rest and for retaining a lubricant therein while the rotating member is rotating. The concave shape is such that while the rotating member is rotating a centrifugal force causes a lubricant to be forced away from the central axis to form a cylindrical surface having an axis collinear with the central axis. This centrifugally displaced lubricant provides restoring forces to counteract lateral displacement during operation.
Centrifugally activated bearing for high-speed rotating machinery
Post, R.F.
1994-02-15T23:59:59.000Z
A centrifugally activated bearing is disclosed. The bearing includes an annular member that extends laterally and radially from a central axis. A rotating member that rotates about the central axis relative to the annular member is also included. The rotating member has an interior chamber that surrounds the central axis and in which the annular member is suspended. Furthermore, the interior chamber has a concave shape for retaining a lubricant therein while the rotating member is at rest and for retaining a lubricant therein while the rotating member is rotating. The concave shape is such that while the rotating member is rotating a centrifugal force causes a lubricant to be forced away from the central axis to form a cylindrical surface having an axis collinear with the central axis. This centrifugally displaced lubricant provides restoring forces to counteract lateral displacement during operation. 4 figures.
Actuator assembly including a single axis of rotation locking member
Quitmeyer, James N.; Benson, Dwayne M.; Geck, Kellan P.
2009-12-08T23:59:59.000Z
An actuator assembly including an actuator housing assembly and a single axis of rotation locking member fixedly attached to a portion of the actuator housing assembly and an external mounting structure. The single axis of rotation locking member restricting rotational movement of the actuator housing assembly about at least one axis. The single axis of rotation locking member is coupled at a first end to the actuator housing assembly about a Y axis and at a 90.degree. angle to an X and Z axis providing rotation of the actuator housing assembly about the Y axis. The single axis of rotation locking member is coupled at a second end to a mounting structure, and more particularly a mounting pin, about an X axis and at a 90.degree. angle to a Y and Z axis providing rotation of the actuator housing assembly about the X axis. The actuator assembly is thereby restricted from rotation about the Z axis.
Lacy, Kyle; Cooke, Chris; Cooke, Pat; Schupbach, Justin; Vaidya, Rahul
2015-01-01T23:59:59.000Z
after Video. Low-cost alternative external rotation shoulder1 : January 2015 Lacy et al. Alternative External RotationMedicine Lacy et al. Alternative External Rotation Shoulder
An EFE model on skin-sleeve interactions during arm rotation.
Xing, Malcolm M Q; Sun, Zhiguo; Pan, Ning; Zhong, Wen; Maibach, Howard I
2006-01-01T23:59:59.000Z
Sleeve Interactions During Arm Rotation Skin and garmentduring rotation of the arm. Normalized effective shearand the sleeve during the arm rotation are provided to re?
Microscopic origin of quantum chaos in rotational damping
Matsuo, M.; Dossing, T.; Vigezzi, E.; Broglia, R.A. (Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto (Japan) The Niels Bohr Institute, University of Copenhagen (Denmark) Instituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano (Italy) Departimento di Fisica dell'Universita di Milano, Milano (Italy))
1993-05-03T23:59:59.000Z
The rotational spectrum of [sup 168]Yb is calclated by diagonalizing different effective interactions within the basis of unperturbed rotational bands provided by the cranked shell model. A transition between order and chaos taking place in the energy region between 1 and 2 MeV above the yrast line is observed, associated with the onset of rotational damping. It can be related to the higher multipole components of the force acting among the unperturbed rotational bands.
Three-dimensional simulation of a rotating supernova
Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Kuroda, T. [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Takiwaki, T. [Center for Computational Astrophysics, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Kotake, K. [Department of Applied Physics, Fukuoka University, Jonan, Fukuoka 814-0180 (Japan)
2014-05-02T23:59:59.000Z
We investigate the effects of rotation on the evolution of core-collapse supernova explosion using a 15 solar mass progenitor model with a variety of neutrino luminosity and rotational velocity. Stars should have some amount of angular momentum, which would affect stellar evolution and its final explosion. In this paper we focus on the effect of rotation on gravitational collapse of a core, on a core bounce of accreting matter, and on subsequent generation and evolution of a shock wave. We find that the rotation plays a positive role for supernova explosions. More rapidly rotating models present more rapid expansion of the shock front and more energetic explosions. When the rotational speed is moderate, the shock once stalls at about 200 km away from the center similarly to a non-rotating model. Then the rotating progenitor experiences effective neutrino heating especially around an equatorial plane and explodes even with somewhat low neutrino luminosity for which the non-rotating model cannot overcome accreting matter and finally collapses. When the rotational speed is fast, the shock expands to about 300 km immediately after the core bounce and then evolves to move outward without shock stalling. We conclude that this positive effect of rotation to explosions is dominant against some possible negative aspects, for example, lower neutrino luminosity caused by less contraction of the rotating core.
Steady periodic waves bifurcating for fixed-depth rotational flows
consider steady periodic water waves for rotational flows with a specified fixed-depth over a flat bed. We the existence of steady periodic water waves for rotational flows with a specified fixed depth over a flat bedSteady periodic waves bifurcating for fixed-depth rotational flows David Henry School
LABORATORY ROTATION REGISTRATION FORM Part III: ACKNOWLEDGED APPROVED BY
Emmons, Scott
LABORATORY ROTATION REGISTRATION FORM Part III: ACKNOWLEDGED APPROVED BY Part II: ROTATION LABORATORY INFORMATION Instructions to the student: This form must be submitted with a completed OSHA Form). The Associate Dean's signature will be obtained by the Graduate Office. First Laboratory Rotation Period
Modeling and Control of Surge and Rotating Stall in Compressors
Gravdahl, Jan Tommy
Modeling and Control of Surge and Rotating Stall in Compressors Dr.ing. thesis Jan Tommy Gravdahl of rotating stall and surge in compressors. A close coupled valve is included in the Mooreconstant compressor speed is derived by extending the MooreGreitzer model. Rotating stall and surge is studied
Modeling and Control of Surge and Rotating Stall in Compressors
Gravdahl, Jan Tommy
Modeling and Control of Surge and Rotating Stall in Compressors Dr.ing. thesis Jan Tommy Gravdahl of rotating stall and surge in compressors. A close coupled valve is included in the Moore-constant compressor speed is derived by extending the Moore-Greitzer model. Rotating stall and surge is studied
Generalization of rotational mechanics and application to aerospace systems
Sinclair, Andrew James
2005-08-29T23:59:59.000Z
-dimensions and the derivative of the principal-rotation parameters. A new minimum-parameter description of N-dimensional orientation is directly related to the principal-rotation parameters. The mapping of arbitrary dynamical systems into N-dimensional rotations and the merits...
Rotating cylindrical wormholes and energy conditions
Bronnikov, K A
2015-01-01T23:59:59.000Z
We seek wormholes among rotating cylindrically symmetric configurations in general relativity. Exact wormhole solutions are presented with such sources of gravity as a massless scalar field, a cosmological constant, and a scalar field with an exponential potential. However, none of these solutions are asymptotically flat, which excludes the existence of wormhole entrances as local objects in our Universe. To overcome this difficulty, we try to build configurations with flat asymptotic regions using the cut-and-paste procedure: on both sides of the throat, a wormhole solution is matched to a properly chosen region of flat space-time at some surfaces $\\Sigma_-$ and $\\Sigma_+$. It is shown, however, that if the source of gravity in the throat region is a scalar field with an arbitrary potential, then one or both thin shells appearing on $\\Sigma_-$ and $\\Sigma_+$ inevitably violate the null energy condition. Thus, although rotating wormhole solutions are easily found without exotic matter, such matter is still ne...
MEMS inertial sensors with integral rotation means.
Kohler, Stewart M.
2003-09-01T23:59:59.000Z
The state-of-the-art of inertial micro-sensors (gyroscopes and accelerometers) has advanced to the point where they are displacing the more traditional sensors in many size, power, and/or cost-sensitive applications. A factor limiting the range of application of inertial micro-sensors has been their relatively poor bias stability. The incorporation of an integral sensitive axis rotation capability would enable bias mitigation through proven techniques such as indexing, and foster the use of inertial micro-sensors in more accuracy-sensitive applications. Fabricating the integral rotation mechanism in MEMS technology would minimize the penalties associated with incorporation of this capability, and preserve the inherent advantages of inertial micro-sensors.
Thermal energy scavenger (rotating wire modules)
Hochstein, P.A.; Milton, H.W.; Pringle, W.L.
1980-11-04T23:59:59.000Z
A thermal energy scavenger assembly is is described including a plurality of temperature-sensitive wires made of material which exhibits shape memory due to a thermoelastic, martensitic phase transformation. The wires are placed in tension between fixed and movable plates which are, in turn, supported by a pair of wheels which are rotatably supported by a housing for rotation about a central axis. A pair of upper and lower cams are fixed to the housing and cam followers react with the respective cams. Each cam transmits forces through a pair of hydraulic pistons. One of the pistons is connected to a movable plate to which one end of the wires are connected whereby a stress is applied to the wires to strain the wires during a first phase and whereby the cam responds to the unstraining of the wires during a second phase. A housing defines fluid compartments through which hot and cold fluid passes and flows radially through the wires whereby the wires become unstrained and shorten in length when subjected to the hot fluid for causing a reaction between the cam followers and the cams to effect rotation of the wheels about the central axis of the assembly, which rotation of the wheels is extracted through beveled gearing. The wires are grouped into a plurality of independent modules with each module having a movable plate, a fixed plate and the associated hydraulic pistons and cam follower. The hydraulic pistons and cam follower of a module are disposed at ends of the wires opposite from the ends of the wires at which the same components of the next adjacent modules are disposed so that the cam followers of alternate modules react with one of the cams and the remaining cam followers of the remaining modules react with the other cam. There is also included stress limiting means in the form of coil springs associated with alternate ends of the wires for limiting the stress or strain in the wires.
Dynamic simulation of high speed rotating machinery
Morgan, Eddie Lee
1977-01-01T23:59:59.000Z
with emphasis on rotor-bearing system stability are presented in this text. Theoretical discussions are presented to describe several of the forcing mechanisms which initiate instabilities 1n high speed rotating equipment. Also included are observations... of instabilities from in- dustrial experience which are not well understood. The design and construction of a dynamic model of the rotor- bearing system of a centrifugal compressor are reviewed. In addition, the results of stability tests performed on two d1...
Galaxy rotation curves in de Sitter space
Maurice H. P. M. van Putten
2015-01-27T23:59:59.000Z
Dark energy inferred from the observed negative deceleration parameter introduces a small mass of the graviton, that satisfies the Higuchi stability condition. It implies an infra-red modification of gravitation that produces Milgrom's inverse distance law of gravitational attraction in excellent agreement with the observed galaxy rotation curves. We conclude that dark matter is present cosmologically with no need for local clustering in galaxies.
Rotating sample holder at low temperature
Pasternak, Sebastien; Perrin, Florian; Ciatto, Gianluca; Palancher, Herve; Steinmann, Ricardo [European Synchrotron Radiation Facility, 38043 Grenoble (France)
2007-07-15T23:59:59.000Z
A low temperature rotary device (cryoturbine) for use in extended x-ray-absorption fine structure measurements in fluorescence mode has been designed and manufactured. The instrument works at a temperature close to liquid Nitrogen and can reach frequencies up to 100 Hz with good stability. The rotation speed is measured with a light-emitting diode driven in stroboscopic mode by a simple electronic circuit.
Light curves from rapidly rotating neutron stars
Numata, Kazutoshi
2010-01-01T23:59:59.000Z
We calculate light curves produced by a hot spot of a rapidly rotating neutron star, assuming that the spot is perturbed by a core $r$-mode, which is destabilized by emitting gravitational waves. To calculate light curves, we take account of relativistic effects such as the Doppler boost due to the rapid rotation and light bending assuming the Schwarzschild metric around the neutron star. We assume that the core $r$-modes penetrate to the surface fluid ocean to have sufficiently large amplitudes to disturb the spot. For a $l'=m$ core $r$-mode, the oscillation frequency $\\omega\\approx2m\\Omega/[l'(l'+1)]$ defined in the co-rotating frame of the star will be detected by a distant observer, where $l'$ and $m$ are respectively the spherical harmonic degree and the azimuthal wave number of the mode, and $\\Omega$ is the spin frequency of the star. In a linear theory of oscillation, using a parameter $A$ we parametrize the mode amplitudes such that ${\\rm max}\\left(|\\xi_\\theta|,|\\xi_\\phi|\\right)/R=A$ at the surface, w...
Global empirical potentials from purely rotational measurements
Dattani, Nikesh S; Sun, Ming; Johnson, Erin R; Roy, Robert J Le; Ziurys, Lucy M
2014-01-01T23:59:59.000Z
The recent advent of chirped-pulse FTMW technology has created a plethora of pure rotational spectra for molecules for which no vibrational information is known. The growing number of such spectra demands a way to build empirical potential energy surfaces for molecules, without relying on any vibrational measurements. Using ZnO as an example, we demonstrate a powerful technique for efficiently accomplishing this. We first measure eight new ultra-high precision ($\\pm2$ kHz) pure rotational transitions in the $X$-state of ZnO. Combining them with previous high-precision ($\\pm50$ kHz) pure rotational measurements of different transitions in the same system, we have data that spans the bottom 10\\% of the well. Despite not using any vibrational information, our empirical potentials are able to determine the size of the vibrational spacings and bond lengths, with precisions that are more than three and two orders of magnitude greater, respectively, than the most precise empirical values previously known, and the mo...
Ghost condensate model of flat rotation curves
V. V. Kiselev
2005-07-29T23:59:59.000Z
An effective action of ghost condensate with higher derivatives creates a source of gravity and mimics a dark matter in spiral galaxies. We present a spherically symmetric static solution of Einstein--Hilbert equations with the ghost condensate at large distances, where flat rotation curves are reproduced in leading order over small ratio of two energy scales characterizing constant temporal and spatial derivatives of ghost field: $\\mu_*^2$ and $\\mu_\\star^2$, respectively, with a hierarchy $\\mu_\\star\\ll \\mu_*$. We assume that a mechanism of hierarchy is provided by a global monopole in the center of galaxy. An estimate based on the solution and observed velocities of rotations in the asymptotic region of flatness, gives $\\mu_*\\sim 10^{19}$ GeV and the monopole scale in a GUT range $\\mu_\\star\\sim 10^{16}$ GeV, while a velocity of rotation $v_0$ is determined by the ratio: $ \\sqrt{2} v_0^2= \\mu_\\star^2/\\mu_*^2$. A critical acceleration is introduced and naturally evaluated of the order of Hubble rate, that represents the Milgrom's acceleration.
Actomyosin contractility rotates the cell nucleus
Abhishek Kumar; Ananyo Maitra; Madhuresh Sumit; Sriram Ramaswamy; G. V. Shivashankar
2013-09-14T23:59:59.000Z
The nucleus of the eukaryotic cell functions amidst active cytoskeletal filaments, but its response to the stresses carried by these filaments is largely unexplored. We report here the results of studies of the translational and rotational dynamics of the nuclei of single fibroblast cells, with the effects of cell migration suppressed by plating onto fibronectin-coated micro-fabricated patterns. Patterns of the same area but different shapes and/or aspect ratio were used to study the effect of cell geometry on the dynamics. On circles, squares and equilateral triangles, the nucleus undergoes persistent rotational motion, while on high-aspect-ratio rectangles of the same area it moves only back and forth. The circle and the triangle showed respectively the largest and the smallest angular speed. We show that our observations can be understood through a hydrodynamic approach in which the nucleus is treated as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active stresses. Lowering actin contractility selectively by introducing blebbistatin at low concentrations drastically reduced the speed and persistence time of the angular motion of the nucleus. Time-lapse imaging of actin revealed a correlated hydrodynamic flow around the nucleus, with profile and magnitude consistent with the results of our theoretical approach. Coherent intracellular flows and consequent nuclear rotation thus appear to be a generic property that cells must balance by specific mechanisms in order to maintain nuclear homeostasis.
Double-Couple Earthquake Source: Symmetry and Rotation
Kagan, Yan Y
2012-01-01T23:59:59.000Z
We consider statistical analysis of double couple (DC) earthquake focal mechanism orientation. The symmetry of DC changes with its geometrical properties, and the number of 3-D rotations one DC source can be transformed into another depends on its symmetry. Four rotations exist in a general case of DC with the nodal-plane ambiguity, two transformations if the fault plane is known, and one rotation if the sides of the fault plane are known. The symmetry of rotated objects is extensively analyzed in statistical material texture studies, and we apply their results to analyzing DC orientation. We consider theoretical probability distributions which can be used to approximate observational patterns of focal mechanisms. Uniform random rotation distributions for various DC sources are discussed, as well as two non-uniform distributions: the rotational Cauchy and von Mises-Fisher. We discuss how parameters of these rotations can be estimated by a statistical analysis of earthquake source properties in global seismici...
The evolution of rotating very massive stars with LMC composition
Köhler, K; de Koter, A; de Mink, S E; Crowther, P A; Evans, C J; Gräfener, G; Sana, H; Sanyal, D; Schneider, F R N; Vink, J S
2015-01-01T23:59:59.000Z
We present a dense model grid with tailored input chemical composition appropriate for the Large Magellanic Cloud. We use a one-dimensional hydrodynamic stellar evolution code, which accounts for rotation, transport of angular momentum by magnetic fields, and stellar wind mass loss to compute our detailed models. We calculate stellar evolution models with initial masses of 70-500 Msun and with initial surface rotational velocities of 0-550 km/s, covering the core-hydrogen burning phase of evolution. We find our rapid rotators to be strongly influenced by rotationally induced mixing of helium, with quasi-chemically homogeneous evolution occurring for the fastest rotating models. Above 160 Msun, homogeneous evolution is also established through mass loss, producing pure helium stars at core hydrogen exhaustion independent of the initial rotation rate. Surface nitrogen enrichment is also found for slower rotators, even for stars that lose only a small fraction of their initial mass. For models above 150 MZAMS, a...
Romero-Talamas, C. A.; Elton, R. C.; Young, W. C.; Reid, R.; Ellis, R. F. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)
2012-07-15T23:59:59.000Z
Doppler spectroscopy of helium impurities in the Maryland Centrifugal Experiment reveals the simultaneous existence of isorotating and differentially rotating magnetic surfaces. Differential rotation occurs at the innermost surfaces and is conjectured to cause plasma voltage oscillations of hundreds of kilohertz by periodically changing the current path inductance. High-speed images show the periodic expulsion of plasma near the mirror ends at the same frequencies. In spite of this, the critical ionization velocity limit is exceeded, with respect to the vacuum field definition, for at least 0.5 ms.
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)
2014-10-28T23:59:59.000Z
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)].
Advanced Rotating Heat Exchangers | Department of Energy
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Wigner density of a rigid rotator
Malta, C.P. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo (Brazil)] [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo (Brazil); Marshall, T.S. [Department of Mathematics, University of Manchester, Manchester M139PL (United Kingdom)] [Department of Mathematics, University of Manchester, Manchester M139PL (United Kingdom); Santos, E. [Departamento de Fisica Moderna, Universidad de Cantabria, 39005, Santander (Spain)] [Departamento de Fisica Moderna, Universidad de Cantabria, 39005, Santander (Spain)
1997-03-01T23:59:59.000Z
We show that the Wigner density of the rigid rotator, in an appropriate, i.e., four-dimensional, phase space, is positive. This result holds in the ground state (S state), and also in the thermal mixture state at all finite temperatures. We discuss the implications of our result for the description of angular momentum in quantum mechanics; in particular, we reexamine, in the light of this new evidence, the suggestion made by Einstein and Stern [Ann. Phys. {bold 40}, 551 (1913)] that there is a nontrivial distribution of angular momentum in the S state. {copyright} {ital 1997} {ital The American Physical Society}
Rotating electric machine with fluid supported parts
Smith, Jr., Joseph L. (Concord, MA); Kirtley, Jr., James L. (Brookline, MA)
1981-01-01T23:59:59.000Z
A rotating electric machine in which the armature winding thereof and other parts are supported by a liquid to withstand the mechanical stresses applied during transient overloads and the like. In particular, a narrow gap is provided between the armature winding and the stator which supports it and this gap is filled with an externally pressurized viscous liquid. The liquid is externally pressurized sufficiently to balance the static loads on the armature winding. Transient mechanical loads which deform the armature winding alter the gap dimensions and thereby additionally pressurize the viscous liquid to oppose the armature winding deformation and more nearly uniformly to distribute the resulting mechanical stresses.
Manipulator for rotating and examining small spheres
Weinstein, Berthold W. [Livermore, CA; Willenborg, David L. [Livermore, CA
1980-02-12T23:59:59.000Z
A manipulator which provides fast, accurate rotational positioning of a small sphere, such as an inertial confinement fusion target, which allows inspecting of the entire surface of the sphere. The sphere is held between two flat, flexible tips which move equal amounts in opposite directions. This provides rolling of the ball about two orthogonal axes without any overall translation. The manipulator may be controlled, for example, by an x- and y-axis driven controlled by a mini-computer which can be programmed to generate any desired scan pattern.
Manipulator for rotating and examining small spheres
Weinstein, B.W.; Willenborg, D.L.
1980-02-12T23:59:59.000Z
A manipulator is disclosed which provides fast, accurate rotational positioning of a small sphere, such as an inertial confinement fusion target, which allows inspecting of the entire surface of the sphere. The sphere is held between two flat, flexible tips which move equal amounts in opposite directions. This provides rolling of the ball about two orthogonal axes without any overall translation. The manipulator may be controlled, for example, by an x- and y-axis driven controlled by a mini-computer which can be programmed to generate any desired scan pattern. 8 figs.
Hidden Rotational Symmetries in Magnetic Domain Patterns
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Rotations in the Space of Split Octonions
Merab Gogberashvili
2008-08-18T23:59:59.000Z
The geometrical application of split octonions is considered. The modified Fano graphic, which represents products of the basis units of split octonionic, having David's Star shape, is presented. It is shown that active and passive transformations of coordinates in octonionic '8-space' are not equivalent. The group of passive transformations that leave invariant the norm of split octonions is SO(4,4), while active rotations is done by the direct product of O(3,4)-boosts and real non-compact form of the exceptional group $G_2$. In classical limit these transformations reduce to the standard Lorentz group.
Magnetospheric structure of rotation powered pulsars
Arons, J. (California Univ., Berkeley, CA (USA) California Univ., Livermore, CA (USA). Inst. of Geophysics and Planetary Physics)
1991-01-07T23:59:59.000Z
I survey recent theoretical work on the structure of the magnetospheres of rotation powered pulsars, within the observational constraints set by their observed spindown, their ability to power synchrotron nebulae and their ability to produce beamed collective radio emission, while putting only a small fraction of their energy into incoherent X- and gamma radiation. I find no single theory has yet given a consistent description of the magnetosphere, but I conclude that models based on a dense outflow of pairs from the polar caps, permeated by a lower density flow of heavy ions, are the most promising avenue for future research. 106 refs., 4 figs., 2 tabs.
More on Rotations as Spin Matrix Polynomials
Thomas L. Curtright
2015-07-11T23:59:59.000Z
Any nonsingular function of spin j matrices always reduces to a matrix polynomial of order 2j. The challenge is to find a convenient form for the coefficients of the matrix polynomial. The theory of biorthogonal systems is a useful framework to meet this challenge. Central factorial numbers play a key role in the theoretical development. Explicit polynomial coefficients for rotations expressed either as exponentials or as rational Cayley transforms are considered here. Structural features of the results are discussed and compared, and large j limits of the coefficients are examined.
Mixing zones in magnetized differentially rotating stars
V. Urpin
2005-09-29T23:59:59.000Z
We study the secular instability of magnetized differentially rotating radiative zones taking account of viscosity and magnetic and thermal diffusivities. The considered instability generalizes the well-known Goldreich-Schubert-Fricke instability for the case of a sufficiently strong magnetic field. In magnetized stars, instability can lead to a formation of non-spherical unstable zones where weak turbulence mixes the material between the surface and interiors. Such unstable zones can manifest themselves by a non-spherical distribution of abundance anormalies on the stellar surface.
Collisional Penrose Process in Rotating Wormhole Spacetime
Naoki Tsukamoto; Cosimo Bambi
2015-05-29T23:59:59.000Z
In a collisional Penrose process, two particles coming from the asymptotically flat region collide in the ergosphere of a compact object. The collision produces two new particles, one with positive energy and one with negative energy. When the particle with positive energy escapes to infinity, the process extracts energy from the compact object. In this paper, we study the collisional Penrose process in a rotating wormhole spacetime. We consider the simple case of a head-on collision at the throat of a Teo wormhole. We find that the process of energy extraction from a Teo wormhole can be substantially more efficient than the collisional Penrose process in the Kerr black hole spacetime.
Electromagnetic counterparts from counter-rotating relativistic kicked discs
Olindo Zanotti
2011-08-23T23:59:59.000Z
We show the results of two dimensional general relativistic inviscid and isothermal hydrodynamical simulations comparing the behavior of co-rotating (with respect to the black hole rotation) and counter-rotating circumbinary quasi-Keplerian discs in the post merger phase of a supermassive binary black hole system. While confirming the spiral shock generation within the disc due to the combined effects of mass loss and recoil velocity of the black hole, we find that the maximum luminosity of counter-rotating discs is a factor ~(2-12) higher than in the co-rotating case, depending on the spin of the black hole. On the other hand, the luminosity peak happens ~10 days later with respect to the co-rotating case, for a binary with a total mass M~10^6 M_\\odot. Although the global dynamics of counter-rotating discs in the post merger phase of a merging event is very similar to that for co-rotating discs, an important difference has been found. In fact, increasing the spin of the central black hole produces more luminous co-rotating discs while less luminous counter-rotating ones.
Dynamics and Statistical Mechanics of Rotating and non-Rotating Vortical Flows
Lim, Chjan [RPI] [RPI
2013-12-18T23:59:59.000Z
Three projects were analyzed with the overall aim of developing a computational/analytical model for estimating values of the energy, angular momentum, enstrophy and total variation of fluid height at phase transitions between disordered and self-organized flow states in planetary atmospheres. It is believed that these transitions in equilibrium statistical mechanics models play a role in the construction of large-scale, stable structures including super-rotation in the Venusian atmosphere and the formation of the Great Red Spot on Jupiter. Exact solutions of the spherical energy-enstrophy models for rotating planetary atmospheres by Kac's method of steepest descent predicted phase transitions to super-rotating solid-body flows at high energy to enstrophy ratio for all planetary spins and to sub-rotating modes if the planetary spin is large enough. These canonical statistical ensembles are well-defined for the long-range energy interactions that arise from 2D fluid flows on compact oriented manifolds such as the surface of the sphere and torus. This is because in Fourier space available through Hodge theory, the energy terms are exactly diagonalizable and hence has zero range, leading to well-defined heat baths.
Faraday rotation: effect of magnetic field reversals
Melrose, D B
2010-01-01T23:59:59.000Z
The standard formula for the rotation measure, RM, which determines the position angle, $\\psi={\\rm RM}\\lambda^2$, 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 \\cite{BB10}, $\\Delta\\psi$ 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 correc...
FARADAY ROTATION: EFFECT OF MAGNETIC FIELD REVERSALS
Melrose, D. B. [SIfA, School of Physics, University of Sydney, NSW 2006 (Australia)
2010-12-20T23:59:59.000Z
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.
Extremal Limits of Rotating Black Holes
Laura Andrianopoli; Riccardo D'Auria; Antonio Gallerati; Mario Trigiante
2013-05-30T23:59:59.000Z
We consider non-extremal, stationary, axion-dilaton solutions to ungauged symmetric supergravity models, obtained by Harrison transformations of the non-extremal Kerr solution. We define a general algebraic procedure, which can be viewed as an Inonu-Wigner contraction of the Noether charge matrix associated with the effective D=3 sigma-model description of the solution, yielding, through different singular limits, the known BPS and non-BPS extremal black holes (which include the under-rotating non-BPS one). The non-extremal black hole can thus be thought of as "interpolating" among these limit-solutions. The algebraic procedure that we define generalizes the known Rasheed-Larsen limit which yielded, in the Kaluza-Klein theory, the first instance of under-rotating extremal solution. As an example of our general result, we discuss in detail the non-extremal solution in the T^3-model, with either (q_0, p^1) or (p^0, q_1) charges switched on, and its singular limits. Such solutions, computed in D=3 through the solution-generating technique, is completely described in terms of D=4 fields, which include the fully integrated vector fields.
Test particle acceleration by rotating jet magnetospheres
F. M. Rieger; K. Mannheim
2000-11-01T23:59:59.000Z
Centrifugal acceleration of charged test particles at the base of a rotating jet magnetosphere is considered. Based on an analysis of forces we derive the equation for the radial accelerated motion and present an analytical solution. It is shown that for particles moving outwards along rotating magnetic field lines, the energy gain is in particular limited by the breakdown of the bead-on-the-wire approximation which occurs in the vicinity of the light cylinder $r_{L}$. The corresponding upper limit for the maximum Lorentz factor $\\gamma_{max}$ for electrons scales $\\propto B^{2/3} r_{L}^{2/3}$, with $B$ the magnetic field strength at $r_{L}$, and is at most of the order of a $10^2-10^3$ for the conditions regarded to be typical for BL Lac objects. Such values suggest that this mechanism may provide pre-accelerated seed particles which are required for efficient Fermi-type particle acceleration at larger scales in radio jets.
Actomyosin contractility rotates the cell nucleus
Kumar, Abhishek; Sumit, Madhuresh; Ramaswamy, Sriram; Shivashankar, G V
2013-01-01T23:59:59.000Z
The nucleus of the eukaryotic cell functions amidst active cytoskeletal filaments, but its response to the stresses carried by these filaments is largely unexplored. We report here the results of studies of the translational and rotational dynamics of the nuclei of single fibroblast cells, with the effects of cell migration suppressed by plating onto fibronectin-coated micro-fabricated patterns. Patterns of the same area but different shapes and/or aspect ratio were used to study the effect of cell geometry on the dynamics. On circles, squares and equilateral triangles, the nucleus undergoes persistent rotational motion, while on high-aspect-ratio rectangles of the same area it moves only back and forth. The circle and the triangle showed respectively the largest and the smallest angular speed. We show that our observations can be understood through a hydrodynamic approach in which the nucleus is treated as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active...
Rotational actuator of motor based on carbon nanotubes
Zettl, Alexander K. (Kensington, CA); Fennimore, Adam M. (Berkeley, CA); Yuzvinsky, Thomas D. (Berkeley, CA)
2008-11-18T23:59:59.000Z
A rotational actuator/motor based on rotation of a carbon nanotube is disclosed. The carbon nanotube is provided with a rotor plate attached to an outer wall, which moves relative to an inner wall of the nanotube. After deposit of a nanotube on a silicon chip substrate, the entire structure may be fabricated by lithography using selected techniques adapted from silicon manufacturing technology. The structures to be fabricated may comprise a multiwall carbon nanotube (MWNT), two in plane stators S1, S2 and a gate stator S3 buried beneath the substrate surface. The MWNT is suspended between two anchor pads and comprises a rotator attached to an outer wall and arranged to move in response to electromagnetic inputs. The substrate is etched away to allow the rotor to freely rotate. Rotation may be either in a reciprocal or fully rotatable manner.
Alpha Channeling in Rotating Plasma with Stationary Waves
A. Fetterman and N.J. Fisch
2010-02-15T23:59:59.000Z
An extension of the alpha channeling effect to supersonically rotating mirrors shows that the rotation itself can be driven using alpha particle energy. Alpha channeling uses radiofrequency waves to remove alpha particles collisionlessly at low energy. We show that stationary magnetic fields with high n? can be used for this purpose, and simulations show that a large fraction of the alpha energy can be converted to rotation energy.
Laser induced rotation of trapped chiral and achiral nematic droplets
Marjan Mosallaeipour; Yashodhan Hatwalne; N. V. Madhusudana; Sharath Ananthamurthy
2010-02-05T23:59:59.000Z
We study the response of optically trapped achiral and chiralised nematic liquid crystal droplets to linear as well as circular polarised light. We find that there is internal dissipation in rotating achiral nematic droplets trapped in glycerine. We also demonstrate that some chiralised droplets rotate under linearly polarised light. The best fit to our data on chiralised droplets indicates that rotational frequency of these droplets with radius R is approximately proportional to1/R^2, rather than to 1/R^3.
Generation of Closed Timelike Curves with Rotating Superconductors
Clovis Jacinto de Matos
2007-01-19T23:59:59.000Z
The spacetime metric around a rotating SuperConductive Ring (SCR) is deduced from the gravitomagnetic London moment in rotating superconductors. It is shown that theoretically it is possible to generate Closed Timelike Curves (CTC) with rotating SCRs. The possibility to use these CTC's to travel in time as initially idealized by G\\"{o}del is investigated. It is shown however, that from a technology and experimental point of view these ideas are impossible to implement in the present context.
Title: Super-rotation and Great Red Spots -- statistical mechanics ...
All known slowly-rotating cases in the solar system - Venus and Titan - have ... low mechanical energy to enstrophy ratios of these self-organizing phenomena.
Study of vorticity in an exact rotating hydro model
L. P. Csernai; J. H. Inderhaug
2015-03-11T23:59:59.000Z
We study a semianalytic exact solution of the fluid dynamical model of heavy ion reactions, and evaluate some observable signs of the rotation.
An Unconditionally Stable Rotational Velocity-Correction Scheme ...
The scheme of Karniadakis et al [16] is equivalent to the velocity-correction scheme in rotational form [14]. The consistent splitting scheme was introduced in [13].
Study of vorticity in an exact rotating hydro model
Csernai, L P
2015-01-01T23:59:59.000Z
We study a semianalytic exact solution of the fluid dynamical model of heavy ion reactions, and evaluate some observable signs of the rotation.
The influence of cracks in rotating shafts
Sinou, Jean-Jacques
2008-01-01T23:59:59.000Z
In this paper, the influence of transverse cracks in a rotating shaft is analysed. The paper addresses the two distinct issues of the changes in modal properties and the influence of crack breathing on dynamic response during operation. Moreover, the evolution of the orbit of a cracked rotor near half of the first resonance frequency is investigated. The results provide a possible basis for an on-line monitoring system. In order to conduct this study, the dynamic response of a rotor with a breathing crack is evaluated by using the alternate frequency/time domain approach. It is shown that this method evaluates the nonlinear behaviour of the rotor system rapidly and efficiently by modelling the breathing crack with a truncated Fourier series. The dynamic response obtained by applying this method is compared with that evaluated through numerical integration. The resulting orbit during transient operation is presented and some distinguishing features of a cracked rotor are examined.
The influence of cracks in rotating shafts
Jean-Jacques Sinou; A. W. Lees
2008-01-19T23:59:59.000Z
In this paper, the influence of transverse cracks in a rotating shaft is analysed. The paper addresses the two distinct issues of the changes in modal properties and the influence of crack breathing on dynamic response during operation. Moreover, the evolution of the orbit of a cracked rotor near half of the first resonance frequency is investigated. The results provide a possible basis for an on-line monitoring system. In order to conduct this study, the dynamic response of a rotor with a breathing crack is evaluated by using the alternate frequency/time domain approach. It is shown that this method evaluates the nonlinear behaviour of the rotor system rapidly and efficiently by modelling the breathing crack with a truncated Fourier series. The dynamic response obtained by applying this method is compared with that evaluated through numerical integration. The resulting orbit during transient operation is presented and some distinguishing features of a cracked rotor are examined.
Orthotropic rotation-free thin shell elements
Munglani, Gautam; Wittel, Falk K; Herrmann, Hans J
2015-01-01T23:59:59.000Z
A method to simulate orthotropic behaviour in thin shell finite elements is proposed. The approach is based on the transformation of shape function derivatives, resulting in a new orthogonal basis aligned to a specified preferred direction for all elements. This transformation is carried out solely in the undeformed state leaving minimal additional impact on the computational effort expended to simulate orthotropic materials compared to isotropic, resulting in a straightforward and highly efficient implementation. This method is implemented for rotation-free triangular shells using the finite element framework built on the Kirchhoff--Love theory employing subdivision surfaces. The accuracy of this approach is demonstrated using the deformation of a pinched hemispherical shell (with a 18{\\deg} hole) standard benchmark. To showcase the efficiency of this implementation, the wrinkling of orthotropic sheets under shear displacement is analyzed. It is found that orthotropic subdivision shells are able to capture t...
How fast can a black hole rotate?
Herdeiro, Carlos A R
2015-01-01T23:59:59.000Z
Kerr black holes have their angular momentum, $J$, bounded by their mass, $M$: $Jc\\leqslant GM^2$. There are, however, known black hole solutions violating this Kerr bound. We propose a very simple universal bound on the rotation, rather than on the angular momentum, of four-dimensional, stationary and axisymmetric, asymptotically flat black holes, given in terms of an appropriately defined horizon linear velocity, $v_H$. The $v_H$ bound is simply that $v_H$ cannot exceed the velocity of light. We verify the $v_H$ bound for known black hole solutions, including some that violate the Kerr bound, and conjecture that only extremal Kerr black holes saturate the $v_H$ bound.
Entropy bounds for uncollapsed rotating bodies
Abreu, Gabriel
2010-01-01T23:59:59.000Z
Entropy bounds in black hole physics, based on a wide variety of different approaches, have had a long and distinguished history. Recently the current authors have turned attention to uncollapsed systems and obtained a robust entropy bound for uncollapsed static spherically symmetric configurations. In the current article we extend this bound to rotating systems. This extension is less simple than one might at first suppose. Purely classically, (using only classical general relativity and basic thermodynamics), it is possible to show that the entropy of uncollapsed matter inside a region enclosed by a surface of area A is bounded from above by S = max kappa(FIDOs) / (2 pi). Thus, using only classical general relativity, basic thermodynamics, and the Unruh effect, we are able to argue that for uncollapsed matter S <= {1/2} A.
Shuang-Qing Wu
2011-10-11T23:59:59.000Z
We construct the solution for non-extremal charged rotating black holes in seven-dimensional gauged supergravity, in the case with only one rotation parameter and two independent charges. Using the Boyer-Lindquist coordinates, the metric is expressed in a generalized form of the ansatz previously presented in [S.Q. Wu, Phys. Rev. D 83 (2011) 121502(R)], which may be helpful to find the most general non-extremal two-charged rotating black hole with three unequal rotation parameters. The conserved charges for thermodynamics are also computed.
The impact of gas bulk rotation on the Ly? line
Garavito-Camargo, Juan N.; Forero-Romero, Jaime E. [Departamento de Física, Universidad de los Andes, Cra. 1 No. 18A-10, Edificio Ip, Bogotá (Colombia); Dijkstra, Mark, E-mail: jn.garavito57@uniandes.edu.co, E-mail: je.forero@uniandes.edu.co, E-mail: mark.dijkstra@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, 0858 Oslo (Norway)
2014-11-10T23:59:59.000Z
We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Ly? emission line in distant galaxies. We model a galaxy as a sphere with an homogeneous mixture of dust and hydrogen at a constant temperature. These spheres undergo solid-body rotation with maximum velocities in the range 0-300 km s{sup –1} and neutral hydrogen optical depths in the range ?{sub H} = 10{sup 5}-10{sup 7}. We consider two types of source distributions in the sphere: central and homogeneous. Our main result is that rotation introduces a dependence of the line morphology with viewing angle and rotational velocity. Observations with a line of sight parallel to the rotation axis yield line morphologies similar to the static case. For lines of sight perpendicular to the rotation axis, both the intensity at the line center and the line width increase with rotational velocity. Along the same line of sight, the line becomes single peaked at rotational velocities close to half the line width in the static case. Notably, we find that rotation does not induce any spatial anisotropy in the integrated line flux, the escape fraction or the average number of scatterings. This is because Lyman scattering through a rotating solid-body proceeds identically to the static case. The only difference is the Doppler shift from the different regions in the sphere that move with respect to the observer. This allows us to derive an analytic approximation for the viewing-angle dependence of the emerging spectrum, as a function of rotational velocity.
MULTI-DIMENSIONAL SIMULATIONS OF ROTATING PAIR-INSTABILITY SUPERNOVAE
Chatzopoulos, E.; Wheeler, J. Craig [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Couch, Sean M., E-mail: manolis@astro.as.utexas.edu [Department of Astronomy and Astrophysics, Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States)
2013-10-20T23:59:59.000Z
We study the effects of rotation on the dynamics, energetics, and {sup 56}Ni production of pair instability supernova (PISN) explosions by performing rotating two-dimensional ({sup 2}.5D{sup )} hydrodynamics simulations. We calculate the evolution of eight low-metallicity (Z = 10{sup –3}, 10{sup –4} Z{sub ?}) massive (135-245 M{sub ?}) PISN progenitors with initial surface rotational velocities of 50% of the critical Keplerian value using the stellar evolution code MESA. We allow for both the inclusion and the omission of the effects of magnetic fields in the angular momentum transport and in chemical mixing, resulting in slowly rotating and rapidly rotating final carbon-oxygen cores, respectively. Increased rotation for carbon-oxygen cores of the same mass and chemical stratification leads to less energetic PISN explosions that produce smaller amounts of {sup 56}Ni due to the effect of the angular momentum barrier that develops and slows the dynamical collapse. We find a non-monotonic dependence of {sup 56}Ni production on rotational velocity in situations when smoother composition gradients form at the outer edge of the rotating cores. In these cases, the PISN energetics are determined by the competition of two factors: the extent of chemical mixing in the outer layers of the core due to the effects of rotation in the progenitor evolution and the development of angular momentum support against collapse. Our 2.5D PISN simulations with rotation are the first presented in the literature. They reveal hydrodynamic instabilities in several regions of the exploding star and increased explosion asymmetries with higher core rotational velocity.
Inwardly Rotating Spiral Waves in a Reaction-Diffusion System
Epstein, Irving R.
in an autocatalytic reaction. The local curvature near the open wave ends is high, making the velocity of the endInwardly Rotating Spiral Waves in a Reaction-Diffusion System Vladimir K. Vanag and Irving R in the spatially extended Belousov-Zhabotinsky (BZ) reaction. Since then, rotating spirals and target waves have
Rotation as an origin of high energy particle collisions
Zaslavskii, O B
2015-01-01T23:59:59.000Z
We consider collision of two particles in rotating spacetimes without horizons. If the metric coefficient responsible for rotation of spacetime is big enough in some region, the energy of collisions in the centre of mass frame can be as large as one likes. The results are model-independent and apply both to relativistic stars and wormholes.
The Pioneer Anomaly and a Rotating Gödel Universe
Thomas L. Wilson; Hans-Joachim Blome
2009-08-27T23:59:59.000Z
Based upon a simple cosmological model with no expansion, we find that the rotational terms appearing in the G/"odel universe are too small to explain the Pioneer anomaly. Although it contributes, universal rotation is not the cause of the Pioneer effect.
Differential rotation of the unstable nonlinear r-modes
Friedman, John L; Lockitch, Keith H
2015-01-01T23:59:59.000Z
At second order in perturbation theory, the $r$-modes of uniformly rotating stars include an axisymmetric part that can be identified with differential rotation of the background star. If one does not include radiation-reaction, the differential rotation is constant in time and has been computed by S\\'a. It has a gauge dependence associated with the family of time-independent perturbations that add differential rotation to the unperturbed equilibrium star: For stars with a barotropic equation of state, one can add to the time-independent second-order solution arbitrary differential rotation that is stratified on cylinders (that is a function of distance $\\varpi$ to the axis of rotation). We show here that the gravitational radiation-reaction force that drives the $r$-mode instability removes this gauge freedom: The expontially growing differential rotation of the unstable second-order $r$-mode is unique. We derive a general expression for this rotation law for Newtonian models and evaluate it explicitly for s...
Viscosity driven instability in rotating relativistic stars Motoyuki Saijo*
Gourgoulhon, Eric
are secularly unstable to bar-mode formation when #12; * #12;sec ' 0:14. This instability can grow of the system. By contrast, a dynamical insta- bility to bar-mode formation sets in when #12; * #12;dyn ' 0. INTRODUCTION Stars in nature are usually rotating and subject to non- axisymmetric rotational instabilities
ROTATIONAL LEADERSHIP PROGRAM Grow strong leadership skillsin a
Kaminsky, Werner
ROTATIONAL LEADERSHIP PROGRAM #12;Grow strong leadership skillsin a one-of-a-kindFortune500. As an Evergreen, you'll be part of an 18-month leadership rotation at our Tacoma and Federal Way, Washington and mentor them to become a valuable part of our leadership succession plan. " Jim Hilger Chief Accounting
Rotational Doppler effect in x-ray photoionization
Sun Yuping; Wang Chuankui [College of Physics and Electronics, Shandong Normal University, 250014 Jinan (China); Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Gel'mukhanov, Faris [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden)
2010-11-15T23:59:59.000Z
The energy of the photoelectron experiences a red or blue Doppler shift when the molecule recedes from the detector or approaches him. This results in a broadening of the photoelectron line due to the translational thermal motion. However, the molecules also have rotational degrees of freedom and we show that the translational Doppler effect has its rotational counterpart. This rotational Doppler effect leads to an additional broadening of the spectral line of the same magnitude as the Doppler broadening caused by translational thermal motion. The rotational Doppler broadening as well as the rotational recoil broadening is sensitive to the molecular orbital from which the photoelectron is ejected. This broadening should be taken into account in analysis of x-ray photoemission spectra of super-high resolution and it can be directly observed using x-ray pump-probe spectroscopy.
Semiclassical pair production rate for rotating electric fields
Eckhard Strobel; She-Sheng Xue
2015-02-09T23:59:59.000Z
We semiclassically investigate Schwinger pair production for pulsed rotating electric fields depending on time. To do so we solve the Dirac equation for two-component fields in a WKB-like approximation. The result shows that for two-component fields the spin distribution of produced pairs is generally not $1:1$. As a result the pair creation rates of spinor and scalar quantum electro dynamics (QED) are different even for one pair of turning points. For rotating electric fields the pair creation rate is dominated by particles with a specific spin depending on the sense of rotation for a certain range of pulse lengths and frequencies. We present an analytical solution for the momentum spectrum of the constant rotating field. We find interference effects not only in the momentum spectrum but also in the total particle number of rotating electric fields.
Coarsening dynamics of binary liquids with active rotation
Syeda Sabrina; Matthew Spellings; Sharon C. Glotzer; Kyle J. M. Bishop
2015-07-24T23:59:59.000Z
Active matter comprised of many self-driven units can exhibit emergent collective behaviors such as pattern formation and phase separation in both biologica and synthetic systems. While these behaviors are increasingly well understood for ensembles of linearly self-propelled particles, less is known about the collective behaviors of active rotating particles where energy input at the particle level gives rise to rotational particle motion. A recent simulation study revealed that active rotation can induce phase separation in mixtures of counter-rotating particles in 2D. In contrast to that of linearly self-propelled particles, the phase separation of counter-rotating fluids is accompanied by steady convective flows that originate at the fluid-fluid interface. Here, we investigate the influence of these flows on the coarsening dynamics of actively rotating binary liquids using a phenomenological, hydrodynamic model that combines a Cahn-Hilliard equation for the fluid composition with a Navier-Stokes equation for the fluid velocity. The effect of active rotation is introduced though an additional force within the Navier-Stokes equations that arises due to gradients in the concentrations of clockwise and counter-clockwise rotating particles. Depending on the strength of active rotation and that of frictional interactions with the stationary surroundings, we observe and explain new dynamical behaviors such as "active coarsening" via self-generated flows as well as the emergence of self-propelled vortex doublets. We confirm that many of the qualitative behaviors identified by the continuum model can also be found in discrete, particle-based simulations of actively rotating liquids. Our results highlight further opportunities for achieving complex dissipative structures in active materials subject to distributed actuation.
Surface aerosol radiative forcing derived from collocated ground-based radiometric
Liou, K. N.
Surface aerosol radiative forcing derived from collocated ground-based radiometric observations-Filter Rotating Shadowband Radiometer data match closely with those from the Cimel sun- photometer data for two of the sunphotometer to retrieve aerosol optical depths, a, along with observed surface flux data from field campaigns
Molecular heat pump for rotational states
C. Lazarou; M. Keller; B. M. Garraway
2010-01-25T23:59:59.000Z
In this work we investigate the theory for three different uni-directional population transfer schemes in trapped multilevel systems which can be utilized to cool molecular ions. The approach we use exploits the laser-induced coupling between the internal and motional degrees of freedom so that the internal state of a molecule can be mapped onto the motion of that molecule in an external trapping potential. By sympathetically cooling the translational motion back into its ground state the mapping process can be employed as part of a cooling scheme for molecular rotational levels. This step is achieved through a common mode involving a laser-cooled atom trapped alongside the molecule. For the coherent mapping we will focus on adiabatic passage techniques which may be expected to provide robust and efficient population transfers. By applying far-detuned chirped adiabatic rapid passage pulses we are able to achieve an efficiency of better than 98% for realistic parameters and including spontaneous emission. Even though our main focus is on cooling molecular states, the analysis of the different adiabatic methods has general features which can be applied to atomic systems.
Round Robin Study of Rotational Strain Rheometers
Clifford, M.J.
2000-02-16T23:59:59.000Z
A round robin of testing was performed to compare the performance of rotational dynamic mechanical spectrometers being used within the nuclear weapons complex. Principals from Sandia National Laboratories/New Mexico; Lockheed Martin Y12 Plant at Oak Ridge, Tennessee; Los Alamos National Laboratory, New Mexico (polycarbonate only); and Honeywell Federal Manufacturing and Technologies (FM and T), Kansas City, MO, performed identical testing of hydrogen blown polysiloxane S5370 and bisphenol-A polycarbonate. Over an oscillation frequency sweep from 0.01 Hz to 15.9 Hz at 135 C, each site produced shear storage modulus values with standard deviations of less than 5%. The data from Sandia, Y12, and Kansas City agreed to within 4%, while the Los Alamos data differed by as much as 13%. Storage modulus values for a frequency sweep of the S5370 at 35 C had standard deviations between 6% and 8%, and site-to-site agreement averaged 3%. The shear loss modulus values had standard deviations of 5%, 7%, and 52% for the sites participating, while the results differed by 12% on average.
Solid State Replacement of Rotating Mirror Cameras
Frank, A M; Bartolick, J M
2006-08-25T23:59:59.000Z
Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed ''In-situ Storage Image Sensor'' or ''ISIS'', by Prof. Goji Etoh, has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.
Novel rotating field probe for inspection of tubes
Xin, J.; Tarkleson, E.; Lei, N.; Udpa, L.; Udpa, S. S. [Nondestructive Evaluation Laboratory, Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, 48824 (United States)
2012-05-17T23:59:59.000Z
Inspection of steam generator tubes in nuclear power plants is extremely critical for safe operation of the power plant. In the nuclear industry, steam generator tube inspection using eddy current techniques has evolved over the years from a single bobbin coil, to rotating probe coil (RPC) and array probe, in an attempt to improve the speed and reliability of inspection. The RPC probe offers the accurate spatial resolution but involves complex mechanical rotation. This paper presents a novel design of eddy current probes based on rotating fields produced by three identical coils excited by a balanced three-phase supply. The sensor thereby achieves rotating probe functionality by electronic means and eliminates the need for mechanical rotation. The field generated by the probe is largely radial that result in induced currents that flow circularly around the radial axis and rotating around the tube at a synchronous speed effectively producing induced eddy currents that are multidirectional. The probe will consequently be sensitive to cracks of all orientations in the tube wall. The finite element model (FEM) results of the rotating fields and induced currents are presented. A prototype probe is being built to validate simulation results.
Double-Couple Earthquake Source: Symmetry and Rotation
Yan Y. Kagan
2012-07-20T23:59:59.000Z
We consider statistical analysis of double couple (DC) earthquake focal mechanism orientation. The symmetry of DC changes with its geometrical properties, and the number of 3-D rotations one DC source can be transformed into another depends on its symmetry. Four rotations exist in a general case of DC with the nodal-plane ambiguity, two transformations if the fault plane is known, and one rotation if the sides of the fault plane are known. The symmetry of rotated objects is extensively analyzed in statistical material texture studies, and we apply their results to analyzing DC orientation. We consider theoretical probability distributions which can be used to approximate observational patterns of focal mechanisms. Uniform random rotation distributions for various DC sources are discussed, as well as two non-uniform distributions: the rotational Cauchy and von Mises-Fisher. We discuss how parameters of these rotations can be estimated by a statistical analysis of earthquake source properties in global seismicity. We also show how earthquake focal mechanism orientations can be displayed on the Rodrigues vector space.
Centrifugal force induced by relativistically rotating spheroids and cylinders
Joseph Katz; Donald Lynden-Bell; Jiri Bicak
2011-02-25T23:59:59.000Z
Starting from the gravitational potential of a Newtonian spheroidal shell we discuss electrically charged rotating prolate spheroidal shells in the Maxwell theory. In particular we consider two confocal charged shells which rotate oppositely in such a way that there is no magnetic field outside the outer shell. In the Einstein theory we solve the Ernst equations in the region where the long prolate spheroids are almost cylindrical; in equatorial regions the exact Lewis "rotating cylindrical" solution is so derived by a limiting procedure from a spatially bound system. In the second part we analyze two cylindrical shells rotating in opposite directions in such a way that the static Levi-Civita metric is produced outside and no angular momentum flux escapes to infinity. The rotation of the local inertial frames in flat space inside the inner cylinder is thus exhibited without any approximation or interpretational difficulties within this model. A test particle within the inner cylinder kept at rest with respect to axes that do not rotate as seen from infinity experiences a centrifugal force. Although the spacetime there is Minkowskian out to the inner cylinder nevertheless that space has been induced to rotate, so relative to the local inertial frame the particle is traversing a circular orbit.
Centrifugal force reversal from the perspective of rigidly rotating observer
Giorgi Dalakishvili
2011-12-26T23:59:59.000Z
In previous studies the dynamics of the relativistic particle moving along the rotating pipe was investigated. The simple gedanken experiment was considered. It was shown that at large enough velocities a centrifugal force acting on the bead changes its usual sign and attracts towards the rotation axis. The authors studied motion of the particle along the rotating straight pipe in the frame of the observer located in the center of rotation, also dynamics of centrifugally accelerated relativistic particle was studied in the laboratory frame. In the both cases it was shown that centrifugal force changes sign. Recently the problem was studied in the frame of stationary observers. It was argued that centrifugal acceleration reversal is not frame invariant effect. In the present paper we consider motion of particle along the rotating straight line in the frame of an arbitrary stationary observer located at certain distance form the center of rotation and rigidly rotating with constant angular velocity. It is shown that any stationary observer could detect reversal of centrifugal acceleration.
Machine protection system for rotating equipment and method
Lakshminarasimha, Arkalgud N. (Marietta, GA); Rucigay, Richard J. (Marietta, GA); Ozgur, Dincer (Kennesaw, GA)
2003-01-01T23:59:59.000Z
A machine protection system and method for rotating equipment introduces new alarming features and makes use of full proximity probe sensor information, including amplitude and phase. Baseline vibration amplitude and phase data is estimated and tracked according to operating modes of the rotating equipment. Baseline vibration and phase data can be determined using a rolling average and variance and stored in a unit circle or tracked using short term average and long term average baselines. The sensed vibration amplitude and phase is compared with the baseline vibration amplitude and phase data. Operation of the rotating equipment can be controlled based on the vibration amplitude and phase.
Symmetries and exact solutions of the rotating shallow water equations
Alexander Chesnokov
2008-08-11T23:59:59.000Z
Lie symmetry analysis is applied to study the nonlinear rotating shallow water equations. The 9-dimensional Lie algebra of point symmetries admitted by the model is found. It is shown that the rotating shallow water equations are related with the classical shallow water model with the change of variables. The derived symmetries are used to generate new exact solutions of the rotating shallow equations. In particular, a new class of time-periodic solutions with quasi-closed particle trajectories is constructed and studied. The symmetry reduction method is also used to obtain some invariant solutions of the model. Examples of these solutions are presented with a brief physical interpretation.
Improvement of the edge rotation diagnostic spectrum analysis via simulation
Luo, J.; Zhuang, G., E-mail: ge-zhuang@hust.edu.cn; Cheng, Z. F.; Zhang, X. L.; Hou, S. Y.; Cheng, C. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)
2014-11-15T23:59:59.000Z
The edge rotation diagnostic (ERD) system has been developed on the Joint Texas Experimental Tokamak to measure the edge toroidal rotation velocity by observing the shifted wavelength of carbon V (C V 227.09 nm). Since the measured spectrum is an integrated result along the viewing line from the plasma core to the edge, a method via simulation has been developed to analyze the ERD spectrum. With the necessary parameters such as C V radiation profile and the ion temperature profile, a local rotation profile at the normalized minor radius of 0.5-1 is obtained.
Quasielastic neutron scattering of -NH3 and -BH3 rotational dynamics...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Quasielastic neutron scattering of -NH3 and -BH3 rotational dynamics in orthorhombic ammonia borane. Quasielastic neutron scattering of -NH3 and -BH3 rotational dynamics in...
Scalar potential model of spiral galaxy HI rotation curves and rotation curve asymmetry
John C. Hodge
2006-11-22T23:59:59.000Z
A scalar potential model (SPM) was developed from considerations of galaxy clusters and of redshift. The SPM is applied to HI rotation curves (RCs) and RC asymmetry of spiral galaxies. The resulting model adds the force of a scalar potential of the host galaxy and of neighboring galaxies to the Newtonian rotation velocity equation. The RC is partitioned radially into regions. The form of the equation for each parameter of each region is the same with differing proportionality constants. Integer values of each equation are determined empirically for each galaxy. Among the sample galaxies, the global properties of galaxies of B band luminosity, of position, and of orientation determine the RC and RC asymmetry. The Source of the scalar field acts as a monopole at distances of a few kpc from the centre of spiral galaxies. The scalar potential field causes Newtonian mechanics to considerably underestimate the mass in galaxies, which is the ``missing mass problem''. The SPM is consistent with RC and RC asymmetry observations of the sample spiral galaxies.
Aerodynamic performance measurements in a counter-rotating aspirated compressor
Onnée, Jean-François
2005-01-01T23:59:59.000Z
This thesis is an experimental investigation of the aerodynamic performances of a counter-rotating aspirated compressor. This compressor is implemented in a blow-down facility, which gives rigorous simulation of the ...
The economics of rotating savings and credit associations
Besley, Timothy
1990-01-01T23:59:59.000Z
This paper examines the role and performance of an institution for allocating savings which is observed world wide - rotating savings and credit associations. We develop a general equilibrium model of an economy with an ...
Contrast from rotating frame relaxation by adiabatic pulses
Michaeli, Shalom (St. Paul, MN); Garwood, Michael G. (Medina, MN); Ugurbil, Kamil (Minneapolis, MN); Sorce, Dennis J. (Cockeysville, MD)
2007-10-09T23:59:59.000Z
This document discusses, among other things, a system and method for modulating transverse and longitudinal relaxation time contrast in a rotating frame based on a train of radio frequency pulses.
Hawking Radiation as Tunneling: the D-dimensional rotating case
M. Nadalini; L. Vanzo; S. Zerbini
2005-11-24T23:59:59.000Z
The tunneling method for the Hawking radiation is revisited and applied to the $D$ dimensional rotating case. Emphasis is given to covariance of results. Certain ambiguities afflicting the procedure are resolved.
Rotating embedded black holes: Entropy and Hawking's radiation
Ng Ibohal
2004-12-27T23:59:59.000Z
In this paper we derive a class of rotating embedded black holes. Then we study Hawking's radiation effects on these embedded black holes. The surface gravity, entropy and angular velocity are given for each of these black holes.
Title of dissertation: TURBULENT SHEAR FLOW IN A RAPIDLY ROTATING
Lathrop, Daniel P.
ABSTRACT Title of dissertation: TURBULENT SHEAR FLOW IN A RAPIDLY ROTATING SPHERICAL ANNULUS Daniel S. Zimmerman, Doctor of Philosophy, 2010 Dissertation directed by: Professor Daniel P. Lathrop Department of Physics This dissertation presents experimental measurements of torque, wall shear stress
Reducing Collective Quantum State Rotation Errors with Reversible Dephasing
Kevin C. Cox; Matthew A. Norcia; Joshua M. Weiner; Justin G. Bohnet; James K. Thompson
2014-07-16T23:59:59.000Z
We demonstrate that reversible dephasing via inhomogeneous broadening can greatly reduce collective quantum state rotation errors, and observe the suppression of rotation errors by more than 21 dB in the context of collective population measurements of the spin states of an ensemble of $2.1 \\times 10^5$ laser cooled and trapped $^{87}$Rb atoms. The large reduction in rotation noise enables direct resolution of spin state populations 13(1) dB below the fundamental quantum projection noise limit. Further, the spin state measurement projects the system into an entangled state with 9.5(5) dB of directly observed spectroscopic enhancement (squeezing) relative to the standard quantum limit, whereas no enhancement would have been obtained without the suppression of rotation errors.
Abstract: Development and Deployment of a Short Rotation Woody...
Broader source: Energy.gov (indexed) [DOE]
highlights a project that will develop a single pass cut and chip harvesting system for short rotation woody crops that will improve the harvesting and logistic costs of processing...
Design and cavitation performance of contra-rotating propellers
Laskos, Dimitrios
2010-01-01T23:59:59.000Z
Improvement of the propulsive efficiency of ships has always been one of the main objectives for naval architects and marine engineers. Contra-Rotating propellers (CRP) are propulsor configurations offering higher efficiency ...
Ferrofluid surface and volume flows in uniform rotating magnetic fields
Elborai, Shihab M. (Shihab Mahmoud), 1977-
2006-01-01T23:59:59.000Z
Ferrofluid surface and volume effects in uniform dc and rotating magnetic fields are studied. Theory and corroborating measurements are presented for meniscus shapes and resulting surface driven flows, spin-up flows, and ...
Graph Rotation Systems for Physical Construction of Large Structures
Xing, Qing
2012-02-14T23:59:59.000Z
In this dissertation, I present an approach for physical construction of large structures. The approach is based on the graph rotation system framework. I propose two kinds of physical structures to represent the shape of design models. I have...
Analysis and experiments for contra-rotating propeller
Kravitz, Eyal
2011-01-01T23:59:59.000Z
Contra-rotating propellers have renewed interest from the naval architecture community, because of the recent development of electric propulsion drives and podded propulsors. Contrarotating propulsion systems have the ...
Supernova Seismology: Gravitational Wave Signatures of Rapidly Rotating Core Collapse
Fuller, Jim; Abdikamalov, Ernazar; Ott, Christian
2015-01-01T23:59:59.000Z
Gravitational waves (GW) generated during a core-collapse supernova open a window into the heart of the explosion. At core bounce, progenitors with rapid core rotation rates exhibit a characteristic GW signal which can be used to constrain the properties of the core of the progenitor star. We investigate the dynamics of rapidly rotating core collapse, focusing on hydrodynamic waves generated by the core bounce and the GW spectrum they produce. The centrifugal distortion of the rapidly rotating proto-neutron star (PNS) leads to the generation of axisymmetric quadrupolar oscillations within the PNS and surrounding envelope. Using linear perturbation theory, we estimate the frequencies, amplitudes, damping times, and GW spectra of the oscillations. Our analysis provides a qualitative explanation for several features of the GW spectrum and shows reasonable agreement with nonlinear hydrodynamic simulations, although a few discrepancies due to non-linear/rotational effects are evident. The dominant early postbounce...
Numerical Study of Flow and Heat Transfer in Rotating Microchannels
Roy, Pratanu
2014-10-07T23:59:59.000Z
Investigation of fluid flow and heat transfer in rotating microchannels is important for centrifugal microfluidics, which has emerged as an advanced technique in biomedical applications and chemical separations. The centrifugal force...
Critical surface for explosions of rotational core-collapse supernovae
Iwakami, Wakana; Nagakura, Hiroki [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502 (Japan); Yamada, Shoichi, E-mail: wakana@heap.phys.waseda.ac.jp [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo, 169-8555 (Japan)
2014-09-20T23:59:59.000Z
The effect of rotation on the explosion of core-collapse supernovae is investigated systematically in three-dimensional simulations. In order to obtain the critical conditions for explosion as a function of mass accretion rate, neutrino luminosity, and specific angular momentum, rigidly rotating matter was injected from the outer boundary with an angular momentum, which is increased every 500 ms. It is found that there is a critical value of the specific angular momentum, above which the standing shock wave revives, for a given combination of mass accretion rate and neutrino luminosity, i.e., an explosion can occur by rotation even if the neutrino luminosity is lower than the critical value for a given mass accretion rate in non-rotational models. The coupling of rotation and hydrodynamical instabilities plays an important role in characterizing the dynamics of shock revival for the range of specific angular momentum that are supposed to be realistic. Contrary to expectations from past studies, the most rapidly expanding direction of the shock wave is not aligned with the rotation axis. Being perpendicular to the rotation axis on average, it can be oriented in various directions. Its dispersion is small when the spiral mode of the standing accretion shock instability (SASI) governs the dynamics, while it is large when neutrino-driven convection is dominant. As a result of the comparison between two-dimensional and three-dimensional rotational models, it is found that m ? 0 modes of neutrino-driven convection or SASI are important for shock revival around the critical surface.
Period tripling causes rotating spirals in agitated wet granular layers
Kai Huang; Ingo Rehberg
2011-07-07T23:59:59.000Z
Pattern formation of a thin layer of vertically agitated wet granular matter is investigated experimentally. Rotating spirals with three arms, which correspond to the kinks between regions with different colliding phases, are the dominating pattern. This preferred number of arms corresponds to period tripling of the agitated granular layer, unlike predominantly subharmonic Faraday crispations in dry granular matter. The chirality of the spatiotemporal pattern corresponds to the rotation direction of the spirals.
Manipulator for rotating and translating a sample holder
van de Water, Jeroen (Breugel, NL); van den Oetelaar, Johannes (Eindhoven, NL); Wagner, Raymond (Gorinchem, NL); Slingerland, Hendrik Nicolaas (Venlo, NL); Bruggers, Jan Willem (Eindhoven, NL); Ottevanger, Adriaan Huibert Dirk (Malden, NL); Schmid, Andreas (Berkeley, CA); Olson, Eric A. (Champaign, IL); Petrov, Ivan G. (Champaign, IL); Donchev, Todor I. (Urbana, IL); Duden, Thomas (Kensington, CA)
2011-02-08T23:59:59.000Z
A manipulator for use in e.g. a Transmission Electron Microscope (TEM) is described, said manipulator capable of rotating and translating a sample holder (4). The manipulator clasps the round sample holder between two members (3A, 3B), said members mounted on actuators (2A, 2B). Moving the actuators in the same direction results in a translation of the sample holder, while moving the actuators in opposite directions results in a rotation of the sample holder.
Balancing of high speed, flexible rotating shafts across critical speeds
White, Gary Paul
1977-01-01T23:59:59.000Z
BALANCING OF HIGH SPEED, FLEXIBLE ROTATING SHAFTS ACROSS CRITICAL SPEEDS A Thesis by Gary Paul White Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... August 1977 Major Subject: Mechanical Engineering Gary Paul White 1977 BALANCING OF HIGH SPEED, FLEXIBLE ROTATING SHAFTS ACROSS CRITICAL SPEEDS A Thesis by GARY PAUL WHITE Approved as to style and content by: Head of Department Member August...
On the Planetary acceleration and the Rotation of the Earth
Arbab I. Arbab
2007-08-06T23:59:59.000Z
We have developed a model for the Earth rotation that gives a good account (data) of the Earth astronomical parameters. These data can be compared with the ones obtained using space-base telescopes. The expansion of the universe has an impact on the rotation of planets, and in particular, the Earth. The expansion of the universe causes an acceleration that is exhibited by all planets.
Generalized rotational Hamiltonians from nonlinear angular momentum algebras
Ballesteros, A.; Herranz, F. J. [Departamento de Fisica, Universidad de Burgos, Pza. Misael Ban(tilde sign)uelos, E-09001 Burgos (Spain); Civitarese, O. [Department of Physics, University of La Plata, C.C. 67 1900, La Plata (Argentina); Reboiro, M. [Department of Physics, University of La Plata, C.C. 67 1900, La Plata (Argentina); Faculty of Engineering, University of Lomas de Zamora C. C. Km 2 (1836) Lavallol (Argentina)
2007-04-15T23:59:59.000Z
Higgs algebras are used to construct rotational Hamiltonians. The correspondence between the spectrum of a triaxial rotor and the spectrum of a cubic Higgs algebra is demonstrated. It is shown that a suitable choice of the parameters of the polynomial algebra allows for a precise identification of rotational properties. The harmonic limit is obtained by a contraction of the algebra, leading to a linear symmetry.
ROTATION AND MULTIPLE STELLAR POPULATION IN GLOBULAR CLUSTERS
Bekki, Kenji [ICRAR, M468, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)
2010-11-20T23:59:59.000Z
We investigate structure and kinematics of the second generation of stars (SG) formed from gaseous ejecta of the first generation of stars (FG) in forming globular clusters (GCs). We consider that SG can be formed from gaseous ejecta from asymptotic giant branch stars of FG with the initial total mass of 10{sup 6} M {sub sun}-10{sup 8} M {sub sun} to explain the present masses of the Galactic GCs. Our three-dimensional hydrodynamical simulations with star formation show that SG formed in the central regions of FG can have a significant amount of rotation (V/{sigma}{approx} 0.8-2.5). The rotational amplitude of SG can depend strongly on the initial kinematics of FG. We thus propose that some GCs composed of FG and SG had a significant amount of rotation when they were formed. We also suggest that although later long-term ({approx}10 Gyr) dynamical evolution of stars can smooth out the initial structural and kinematical differences between FG and SG to a large extent, initial flattened structures and rotational kinematics of SG can be imprinted on shapes and internal rotation of the present GCs. We discuss these results in terms of internal rotation observed in the Galactic GCs.
Influence of Rotations on the Critical State of Soil Mechanics
W. F. Oquendo; J. D. Muñoz; A. Lizcano
2010-11-23T23:59:59.000Z
The ability of grains to rotate can play a crucial role on the collective behavior of granular media. It has been observed in computer simulations that imposing a torque at the contacts modifies the force chains, making support chains less important. In this work we investigate the effect of a gradual hindering of the grains rotations on the so-called critical state of soil mechanics. The critical state is an asymptotic state independent of the initial solid fraction where deformations occur at a constant shear strength and compactness. We quantify the difficulty to rotate by a friction coefficient at the level of particles, acting like a threshold. We explore the effect of this particle-level friction coefficient on the critical state by means of molecular dynamics simulations of a simple shear test on a poly-disperse sphere packing. We found that the larger the difficulty to rotate, the larger the final shear strength of the sample. Other micro-mechanical variables, like the structural anisotropy and the distribution of forces, are also influenced by the threshold. These results reveal the key role of rotations on the critical behavior of soils and suggest the inclusion of rotational variables into their constitutive equations.
Interstitial rotating shield brachytherapy for prostate cancer
Adams, Quentin E., E-mail: quentin-adams@uiowa.edu; Xu, Jinghzu; Breitbach, Elizabeth K.; Li, Xing; Rockey, William R.; Kim, Yusung; Wu, Xiaodong; Flynn, Ryan T. [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)] [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Enger, Shirin A. [Medical Physics Unit, McGill University, 1650 Cedar Ave, Montreal, Quebec H3G 1A4 (Canada)] [Medical Physics Unit, McGill University, 1650 Cedar Ave, Montreal, Quebec H3G 1A4 (Canada)
2014-05-15T23:59:59.000Z
Purpose: To present a novel needle, catheter, and radiation source system for interstitial rotating shield brachytherapy (I-RSBT) of the prostate. I-RSBT is a promising technique for reducing urethra, rectum, and bladder dose relative to conventional interstitial high-dose-rate brachytherapy (HDR-BT). Methods: A wire-mounted 62 GBq{sup 153}Gd source is proposed with an encapsulated diameter of 0.59 mm, active diameter of 0.44 mm, and active length of 10 mm. A concept model I-RSBT needle/catheter pair was constructed using concentric 50 and 75 ?m thick nickel-titanium alloy (nitinol) tubes. The needle is 16-gauge (1.651 mm) in outer diameter and the catheter contains a 535 ?m thick platinum shield. I-RSBT and conventional HDR-BT treatment plans for a prostate cancer patient were generated based on Monte Carlo dose calculations. In order to minimize urethral dose, urethral dose gradient volumes within 0–5 mm of the urethra surface were allowed to receive doses less than the prescribed dose of 100%. Results: The platinum shield reduced the dose rate on the shielded side of the source at 1 cm off-axis to 6.4% of the dose rate on the unshielded side. For the case considered, for the same minimum dose to the hottest 98% of the clinical target volume (D{sub 98%}), I-RSBT reduced urethral D{sub 0.1cc} below that of conventional HDR-BT by 29%, 33%, 38%, and 44% for urethral dose gradient volumes within 0, 1, 3, and 5 mm of the urethra surface, respectively. Percentages are expressed relative to the prescription dose of 100%. For the case considered, for the same urethral dose gradient volumes, rectum D{sub 1cc} was reduced by 7%, 6%, 6%, and 6%, respectively, and bladder D{sub 1cc} was reduced by 4%, 5%, 5%, and 6%, respectively. Treatment time to deliver 20 Gy with I-RSBT was 154 min with ten 62 GBq {sup 153}Gd sources. Conclusions: For the case considered, the proposed{sup 153}Gd-based I-RSBT system has the potential to lower the urethral dose relative to HDR-BT by 29%–44% if the clinician allows a urethral dose gradient volume of 0–5 mm around the urethra to receive a dose below the prescription. A multisource approach is necessary in order to deliver the proposed {sup 153}Gd-based I-RSBT technique in reasonable treatment times.
Hitchcock, Adam P.
with results from Nephila clavipes dragline spider silk measured using the in situ rotation device. © 2007
Division of Astronomy and Space Physics MHD Theory of Rotating Tokamak Plasmas
Division of Astronomy and Space Physics MHD Theory of Rotating Tokamak Plasmas in collaboration stability theory of rotating tokamak plasmas. The research is a part of the Swedish and European research rotation and rotation shear on various MHD modes in tokamak plasmas [3, 4, 5] Fig. 3: Stabilization
ANALYTICAL CALCULATION OF STOKES PROFILES OF ROTATING STELLAR MAGNETIC DIPOLE
Martinez Gonzalez, M. J. [Instituto de Astrofisica de Canarias, Via Lactea s/n, 38200 La Laguna, Tenerife (Spain); Asensio Ramos, A. [Departamento de Astrofisica, Universidad de La Laguna, E-38205 La Laguna, Tenerife (Spain)
2012-08-20T23:59:59.000Z
The observation of the polarization emerging from a rotating star at different phases opens up the possibility to map the magnetic field in the stellar surface thanks to the well-known Zeeman-Doppler imaging. When the magnetic field is sufficiently weak, the circular and linear polarization profiles locally in each point of the star are proportional to the first and second derivatives of the unperturbed intensity profile, respectively. We show that the weak-field approximation (for weak lines in the case of linear polarization) can be generalized to the case of a rotating star including the Doppler effect and taking into account the integration on the stellar surface. The Stokes profiles are written as a linear combination of wavelength-dependent terms expressed as series expansions in terms of Hermite polynomials. These terms contain the surface-integrated magnetic field and velocity components. The direct numerical evaluation of these quantities is limited to rotation velocities not larger than eight times the Doppler width of the local absorption profiles. Additionally, we demonstrate that in a rotating star, the circular polarization flux depends on the derivative of the intensity flux with respect to the wavelength and also on the profile itself. Likewise, the linear polarization depends on the profile and on its first and second derivatives with respect to the wavelength. We particularize the general expressions to a rotating dipole.
Rotational viscometer for high-pressure high-temperature fluids
Carr, Kenneth R. (Knoxville, TN)
1985-01-01T23:59:59.000Z
The invention is a novel rotational viscometer which is well adapted for use with fluids at high temperatures and/or pressures. In one embodiment, the viscometer includes a substantially non-magnetic tube having a closed end and having an open end in communication with a fluid whose viscosity is to be determined. An annular drive magnet is mounted for rotation about the tube. The tube encompasses and supports a rotatable shaft assembly which carries a rotor, or bob, for insertion in the fluid. Affixed to the shaft are (a) a second magnet which is magnetically coupled to the drive magnet and (b) a third magnet. In a typical operation, the drive magnet is rotated to turn the shaft assembly while the shaft rotor is immersed in the fluid. The viscous drag on the rotor causes the shaft assembly to lag the rotation of the drive magnet by an amount which is a function of the amount of viscous drag. A first magnetic pickup generates a waveform whose phase is a function of the angular position of the drive magnet. A second magnetic pickup generates a waveform whose phase is a function of the angular position of the third magnet. An output is generated indicative of the phase difference between the two waveforms.
Analysis of the rotational properties of Kuiper belt objects
Pedro Lacerda; Jane Luu
2006-01-12T23:59:59.000Z
We use optical data on 10 Kuiper Belt objects (KBOs) to investigate their rotational properties. Of the 10, three (30%) exhibit light variations with amplitude delta_m >= 0.15 mag, and 1 out of 10 (10%) has delta_m >= 0.40 mag, which is in good agreement with previous surveys. These data, in combination with the existing database, are used to discuss the rotational periods, shapes, and densities of Kuiper Belt objects. We find that, in the sampled size range, Kuiper Belt objects have a higher fraction of low amplitude lightcurves and rotate slower than main belt asteroids. The data also show that the rotational properties and the shapes of KBOs depend on size. If we split the database of KBO rotational properties into two size ranges with diameter larger and smaller than 400 km, we find that: (1) the mean lightcurve amplitudes of the two groups are different with 98.5% confidence, (2) the corresponding power-law shape distributions seem to be different, although the existing data are too sparse to render this difference significant, and (3) the two groups occupy different regions on a spin period vs. lightcurve amplitude diagram. These differences are interpreted in the context of KBO collisional evolution.
2D Fokker-Planck models of rotating clusters
J. Fiestas; R. Spurzem; E. Kim
2006-09-04T23:59:59.000Z
Globular clusters rotate significantly, and with the increasing amount of detailed morphologicaland kinematical data obtained in recent years on galactic globular clusters many interesting features show up. We show how our theoretical evolutionary models of rotating clusters can be used to obtain fits, which at least properly model the overall rotation and its implied kinematics in full 2D detail (dispersions, rotation velocities). Our simplified equal mass axisymmetric rotatingmodel provides detailed two-dimensional kinematical and morphological data for star clusters. The degree of rotation is not dominant in energy, but also non-negligible for the phase space distribution function, shape and kinematics of clusters. Therefore the models are well applicable for galactic globular clusters. Since previously published papers on that matter by us made it difficult to do detailed comparisons with observations we provide a much more comprehensive and easy-to-use set of data here, which uses as entries dynamical age and flattening of observed cluster andthen offers a limited range of applicable models in full detail. The method, data structure and some exemplary comparison with observations are presented. Future work will improve modelling anddata base to take a central black hole, a mass spectrum and stellar evolution into account.
A nonlinear calculation of rotating cavitation in inducers
Tsujimoto, Y. [Osaka Univ., Toyonaka, Osaka (Japan). Dept. of Mechanical Engineering]|[National Aerospace Lab., Kakuda, Miyagi (Japan); Watanabe, S.; Yoshida, Y. [Osaka Univ., Toyonaka, Osaka (Japan); Kamijo, K. [National Aerospace Lab., Kakuda, Miyagi (Japan)
1996-09-01T23:59:59.000Z
In the previous linear analysis (Tsujimoto et al., 1993) it was found that there can be a backward rotating cavitation as well as a forward mode which rotates faster than impeller. Although some shaft vibration has been observed, which might be caused by the backward mode, experimental evidence has been obtained only for the forward mode. The purpose of the present study is to find out the factors which determine the amplitude of each mode of rotating cavitation by taking into account several nonlinearities. A time marching nonlinear 2-D flow analysis was carried out for this purpose. It was found that the increase of cavitation compliance at lower inlet pressure can be a factor which limits the amplitude. The mode selectivity is mainly dependent on the stability limit obtained by a linear analysis for which the phase delay of cavity has a most important effect.
General Relativistic Rotation Curves in a Post-Newtonian Light
Aleksandar Rakic; Dominik J. Schwarz
2008-11-10T23:59:59.000Z
The missing of a Keplerian fall-off in the observed galaxy rotation curves represents classical evidence for the existence of dark matter on galactic scales. There has been some recent activity concerning the potential of modelling galactic systems with the help of general relativity. This was motivated by claims that by the use of full general relativity dark matter could be made superfluous. Here we focus on possible axisymmetric and stationary solutions of Einstein's equations with rotating dust. After a short review of the current debate we pursue the idea of approaching such relativistic models in a Newtonian language. We analyse rigidly as well as differentially rotating Newtonian and Post-Newtonian spacetimes and find that it is necessary to incorporate a Post-Newtonian term in order to make physical sense.
Effects of Rotational Symmetry Breaking in Polymer-coated Nanopores
Osmanovic, D; Eccleston, R C; Hoogenboom, B W; Ford, I J
2015-01-01T23:59:59.000Z
The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However, simulations have shown that this rotational symmetry can be broken when there are attractive interactions between the polymers. We investigate the phases that emerge in these circumstances, and we quantify the effect of the symmetry assumption on the phase behavior of the system. In the absence of this assumption, one can observe large differences in the equilibrium densities between the rotationally symmetric case and the non-rotationally symmetric case. A simple analytical model is developed that illustrates the driving thermodynamic forces responsible for this symmetry breaking. Our results have implications for the current understanding of the polymer behavior in cylindrical nanopores.
High-spin rotational structures in {sup 76}Kr
Valiente-Dobon, J.J.; Svensson, C.E.; Finlay, P.; Grinyer, G.F.; Hyland, B.; Phillips, A.A.; Schumaker, M.A. [Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); O'Leary, C.D.; Jenkins, D.; Johnston-Theasby, F.; Joshi, P.; Kelsall, N.S.; Wadsworth, R. [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Ragnarsson, I. [Department of Physics, Lund Institute of Technology, P.O. Box 118, S-221 00 Lund (Sweden); Andreoiu, C. [Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 3BX (United Kingdom); Appelbe, D.E. [CLRC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Austin, R.A.E.; Cameron, J.A.; Waddington, J.C. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4K1 (Canada); Ball, G.C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada)] [and others
2005-03-01T23:59:59.000Z
High-spin states in {sup 36}{sub 76}Kr{sub 40} have been populated in the {sup 40}Ca({sup 40}Ca,4p){sup 76}Kr fusion-evaporation reaction at a beam energy of 165 MeV and studied using the Gammasphere and Microball multidetector arrays. The ground-state band and two signature-split negative parity bands of {sup 76}Kr have been extended to {approx}30({Dirac_h}/2{pi}). Lifetime measurements using the Doppler-shift attenuation method show that the transition quadrupole moment of these three bands decrease as they approach their maximum-spin states. Two signatures of a new rotational structure with remarkably rigid rotational behavior have been identified. The high-spin properties of these rotational bands are analyzed within the framework of configuration-dependent cranked Nilsson-Strutinsky calculations.
Regenerative braking device with rotationally mounted energy storage means
Hoppie, Lyle O. (Birmingham, MI)
1982-03-16T23:59:59.000Z
A regenerative braking device for an automotive vehicle includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (30) and an output shaft (32), clutches (50, 56) and brakes (52, 58) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. In a second embodiment the clutches and brakes are dispensed with and the variable ratio transmission is connected directly across the input and output shafts. In both embodiments the rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft rotates faster or relative to the output shaft and are torsionally relaxed to deliver energy to the vehicle when the output shaft rotates faster or relative to the input shaft.
Tidal deformation of a slowly rotating material body. External metric
Philippe Landry; Eric Poisson
2015-07-31T23:59:59.000Z
We construct the external metric of a slowly rotating, tidally deformed material body in general relativity. The tidal forces acting on the body are assumed to be weak and to vary slowly with time, and the metric is obtained as a perturbation of a background metric that describes the external geometry of an isolated, slowly rotating body. The tidal environment is generic and characterized by two symmetric-tracefree tidal moments E_{ab} and B_{ab}, and the body is characterized by its mass M, its radius R, and a dimensionless angular-momentum vector \\chi^a new quantities, which we designate as rotational-tidal Love numbers. All these Love numbers are gauge invariant in the usual sense of perturbation theory, and all vanish when the body is a black hole.
Rotational order–disorder structure of fluorescent protein FP480
Pletnev, Sergei, E-mail: svp@ncifcrf.gov [SAIC-Frederick Inc., Basic Research Program, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Morozova, Kateryna S.; Verkhusha, Vladislav V. [Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 (United States); Dauter, Zbigniew, E-mail: svp@ncifcrf.gov [Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); SAIC-Frederick Inc., Basic Research Program, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)
2009-09-01T23:59:59.000Z
An analysis of the rotational order–disorder structure of fluorescent protein FP480 is presented. In the last decade, advances in instrumentation and software development have made crystallography a powerful tool in structural biology. Using this method, structural information can now be acquired from pathological crystals that would have been abandoned in earlier times. In this paper, the order–disorder (OD) structure of fluorescent protein FP480 is discussed. The structure is composed of tetramers with 222 symmetry incorporated into the lattice in two different ways, namely rotated 90° with respect to each other around the crystal c axis, with tetramer axes coincident with crystallographic twofold axes. The random distribution of alternatively oriented tetramers in the crystal creates a rotational OD structure with statistically averaged I422 symmetry, although the presence of very weak and diffuse additional reflections suggests that the randomness is only approximate.
Temporal Variations in the Sun's Rotational Kinetic Energy
H. M. Antia; S. M. Chitre; D. O. Gough
2007-11-06T23:59:59.000Z
AIM: To study the variation of the angular momentum and the rotational kinetic energy of the Sun, and associated variations in the gravitational multipole moments, on a timescale of the solar cycle. METHOD: Inverting helioseismic rotational splitting data obtained by the Global Oscillation Network Group and by the Michelson Doppler Imager on the Solar and Heliospheric Observatory. RESULTS: The temporal variation in angular momentum and kinetic energy at high latitudes (>\\pi/4) through the convection zone is positively correlated with solar activity, whereas at low latitudes it is anticorrelated, except for the top 10% by radius where both are correlated positively. CONCLUSION: The helioseismic data imply significant temporal variation in the angular momentum and the rotational kinetic energy, and in the gravitational multipole moments. The properties of that variation will help constrain dynamical theories of the solar cycle.
New limits on extragalactic magnetic fields from rotation measures
Pshirkov, Maxim S; Urban, Federico R
2015-01-01T23:59:59.000Z
We take advantage of the wealth of rotation measures data contained in the NVSS catalogue to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-$\\alpha$ clouds. Based on the observation that rotation measures from low-luminosity distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Mpc coherence length to be below 1.2 nG at the $2\\sigma$ level, and fields coherent across the entire observable Universe below 0.5 nG. These limits do not depend on the particular origin of these cosmological fields.
Ultra high vacuum heating and rotating specimen stage
Coombs, A.W. III
1995-05-02T23:59:59.000Z
A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1{times}10{sup {minus}9} torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating. 5 figs.
Ultra high vacuum heating and rotating specimen stage
Coombs, III, Arthur W. (Patterson, CA)
1995-01-01T23:59:59.000Z
A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1.times.10.sup.-9 torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating.
Statistical mechanics of nonequilibrium systems of rotators with alternated spins
Andrey Dymov
2014-12-22T23:59:59.000Z
We consider a finite region of a d-dimensional lattice of nonlinear Hamiltonian rotators, where neighbouring rotators have opposite spins and are coupled by a small potential of order $\\varepsilon^a,\\, a\\geq1/2$. We weakly stochastically perturb the system in such a way that each rotator interacts with its own stochastic Langevin-type thermostat with a force of order $\\varepsilon$. Then we introduce the action-angle variables for the system of uncoupled rotators ($\\varepsilon=0$) and note that the sum of actions over all nodes is conserved by the purely Hamiltonian dynamics of the system with $\\varepsilon>0$. We investigate the limiting (as $\\varepsilon \\rightarrow 0$) dynamics of actions for solutions of the $\\varepsilon$-perturbed system on time intervals of order $\\varepsilon^{-1}$. It turns out that the limiting dynamics is governed by a certain autonomous (stochastic) equation for the vector of actions. This equation has a completely non-Hamiltonian nature. The $\\varepsilon$-perturbed system has a unique stationary measure $\\widetilde \\mu^\\varepsilon$ and is mixing. Any limiting point of the family $\\{\\widetilde \\mu^\\varepsilon\\}$ of stationary measures as $\\varepsilon\\rightarrow 0$ is an invariant measure of the system of uncoupled integrable rotators. There are plenty of such measures. However, it turns out that only one of them describes the limiting dynamics of the $\\varepsilon$-perturbed system: we prove that a limiting point of $\\{\\widetilde\\mu^\\varepsilon\\}$ is unique, its projection to the space of actions is the unique stationary measure of the autonomous equation above, which turns out to be mixing, and its projection to the space of angles is the normalized Lebesque measure on the torus $\\mathbb{T}^N$. Most of results and convergences we obtain are uniform in the number $N$ of rotators.
Spin rotation of polarized beams in high energy storage ring
V. G. Baryshevsky
2006-03-23T23:59:59.000Z
The equations for spin evolution of a particle in a storage ring are obtained considering contributions from the tensor electric and magnetic polarizabilities of the particle along with the contributions from spin rotation and birefringence effect in polarized matter of an internal target. % Study of the spin rotation and birefringence effects for a particle in a high energy storage ring provides for measurement both the spin-dependent real part of the coherent elastic zero-angle scattering amplitude and tensor electric (magnetic) polarizabilities.
Rotation in relativity and the propagation of light
E. Kajari; M. Buser; C. Feiler; W. P. Schleich
2009-05-06T23:59:59.000Z
We compare and contrast the different points of view of rotation in general relativity, put forward by Mach, Thirring and Lense, and Goedel. Our analysis relies on two tools: (i) the Sagnac effect which allows us to measure rotations of a coordinate system or induced by the curvature of spacetime, and (ii) computer visualizations which bring out the alien features of the Goedel Universe. In order to keep the paper self-contained, we summarize in several appendices crucial ingredients of the mathematical tools used in general relativity. In this way, our lecture notes should be accessible to researchers familiar with the basic elements of tensor calculus and general relativity.
Rotation in relativity and the propagation of light
Kajari, E; Feiler, C; Schleich, W P
2009-01-01T23:59:59.000Z
We compare and contrast the different points of view of rotation in general relativity, put forward by Mach, Thirring and Lense, and Goedel. Our analysis relies on two tools: (i) the Sagnac effect which allows us to measure rotations of a coordinate system or induced by the curvature of spacetime, and (ii) computer visualizations which bring out the alien features of the Goedel Universe. In order to keep the paper self-contained, we summarize in several appendices crucial ingredients of the mathematical tools used in general relativity. In this way, our lecture notes should be accessible to researchers familiar with the basic elements of tensor calculus and general relativity.
Rotating charged cylindrical black holes as particle accelerators
Said, Jackson Levi [Physics Department, University of Malta, Msida MSD 2080 (Malta); Adami, Kristian Zarb [Physics Department, University of Malta, Msida MSD 2080 (Malta); Physics Department, University of Oxford, Oxford, OX1 3RH (United Kingdom)
2011-05-15T23:59:59.000Z
It has recently been pointed out that arbitrary center-of-mass energies may be obtained for particle collisions near the horizon of an extremal Kerr black hole. We investigate this mechanism in cylindrical topology. In particular we consider the center-of-mass energies of a cylindrical black hole with an extremal rotation and charge parameter. The geodesics are first derived with a rotating charged cylindrical black hole producing the background gravitational field. Finally the center-of-mass is determined for this background and its extremal limit is taken.
Teleparallel Energy-Momentum Distribution of Spatially Homogeneous Rotating Spacetimes
M. Sharif; M. Jamil Amir
2007-12-08T23:59:59.000Z
The energy-momentum distribution of spatially homogeneous rotating spacetimes in the context of teleparallel theory of gravity is investigated. For this purpose, we use the teleparallel version of Moller prescription. It is found that the components of energy-momentum density are finite and well-defined but are different from General Relativity. However, the energy-momentum density components become the same in both theories under certain assumptions. We also analyse these quantities for some special solutions of the spatially homogeneous rotating spacetimes.
Contactless transfer of angular momentum by rotating laser beam
E. V. Barmina; G. A. Shafeev
2014-07-17T23:59:59.000Z
Contactless transfer of angular momentum from rotating laser beam to a solid target is experimentally demonstrated. The effect is observed under irradiation of a glassy carbon target immersed in water by a pulsed laser beam that is scanned across the target surface along circular trajectory. The direction of target rotation coincides with that of the laser beam at small thickness of the liquid layer above the target while is opposite in case of higher thickness of the layer. The effect is interpreted as the interplay between thermocapillary and convective flows induced in the liquid by laser heating.
Scalar emission in a rotating Gödel black hole
Songbai Chen; Bin Wang; Jiliang Jing
2008-08-23T23:59:59.000Z
We study the absorption probability and Hawking radiation of the scalar field in the rotating G\\"{o}del black hole in minimal five-dimensional gauged supergravity. We find that G\\"{o}del parameter $j$ imprints in the greybody factor and Hawking radiation. It plays a different role from the angular momentum of the black hole in the Hawking radiation and super-radiance. These information can help us know more about rotating G\\"{o}del black holes in minimal five-dimensional gauged supergravity.
Fitting the Galaxy Rotation Curves: Strings versus NFW profile
Yeuk-Kwan E. Cheung; Feng Xu
2008-10-14T23:59:59.000Z
Remarkable fit of galaxy rotation curves is achieved using a simple model from string theory. The rotation curves of the same group of galaxies are also fit using dark matter model with the generalized Navarro-Frenk-White profile for comparison. String model utilizes three free parameters vs five in the dark matter model. The average chi-squared of the string model fit is 1.649 while that of the dark matter model is 1.513. The generalized NFW profile fits marginally better at a price of two more free parameters.
Graphene Monolayer Rotation on Ni(111) Facilities Bilayer Graphene Growth
Batzill M.; Sutter P.; Dahal, A.; Addou, R.
2012-06-11T23:59:59.000Z
Synthesis of bilayer graphene by chemical vapor deposition is of importance for graphene-based field effect devices. Here, we demonstrate that bilayer graphene preferentially grows by carbon-segregation under graphene sheets that are rotated relative to a Ni(111) substrate. Rotated graphene monolayer films can be synthesized at growth temperatures above 650 C on a Ni(111) thin-film. The segregated second graphene layer is in registry with the Ni(111) substrate and this suppresses further C-segregation, effectively self-limiting graphene formation to two layers.
Saha, Kanak
2012-01-01T23:59:59.000Z
Boxy/peanut bulges are believed to originate from galactic discs through secular processes. A little explored question is how this evolution would be modified if the initial disc was assembled around a preexisting classical bulge. Previously we showed that a low-mass initial classical bulge (ICB), as might have been present in Milky Way-like galaxies, can spin up significantly by gaining angular momentum from a bar formed through disc instability. Here we investigate how the disc instability and the kinematics of the final boxy/peanut (BP) bulge depend on the angular momentum of such a low-mass ICB. We show that a strong bar forms and transfers angular momentum to the ICB in all our models. However, rotation in the ICB limits the emission of the bar's angular momentum, which in turn changes the size and growth of the bar, and of the BP bulge formed from the disc. The final BP bulge in these models is a superposition of the BP bulge formed via the buckling instability and the spun-up ICB. We find that the long...
Testing MONDian dark matter with galactic rotation curves
Edmonds, Doug [Department of Physics, Emory and Henry College, Emory, VA 24327 (United States); Farrah, Duncan; Minic, Djordje; Takeuchi, Tatsu [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Ho, Chiu Man [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Ng, Y. Jack, E-mail: dedmonds@ehc.edu, E-mail: farrah@vt.edu, E-mail: dminic@vt.edu, E-mail: takeuchi@vt.edu, E-mail: chiuman.ho@vanderbilt.edu, E-mail: yjng@physics.unc.edu [Institute of Field Physics, Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599 (United States)
2014-09-20T23:59:59.000Z
MONDian dark matter (MDM) is a new form of dark matter quantum that naturally accounts for Milgrom's scaling, usually associated with modified Newtonian dynamics (MOND), and theoretically behaves like cold dark matter (CDM) at cluster and cosmic scales. In this paper, we provide the first observational test of MDM by fitting rotation curves to a sample of 30 local spiral galaxies (z ? 0.003). For comparison, we also fit the galactic rotation curves using MOND and CDM. We find that all three models fit the data well. The rotation curves predicted by MDM and MOND are virtually indistinguishable over the range of observed radii (?1 to 30 kpc). The best-fit MDM and CDM density profiles are compared. We also compare with MDM the dark matter density profiles arising from MOND if Milgrom's formula is interpreted as Newtonian gravity with an extra source term instead of as a modification of inertia. We find that discrepancies between MDM and MOND will occur near the center of a typical spiral galaxy. In these regions, instead of continuing to rise sharply, the MDM mass density turns over and drops as we approach the center of the galaxy. Our results show that MDM, which restricts the nature of the dark matter quantum by accounting for Milgrom's scaling, accurately reproduces observed rotation curves.
ROTATION NUMBERS IN THOMPSON-STEIN GROUPS AND APPLICATIONS
Liousse, Isabelle
ROTATION NUMBERS IN THOMPSON-STEIN GROUPS AND APPLICATIONS ISABELLE LIOUSSE Abstract. We study, the Thompson-Stein groups. We prove that for many Thompson-Stein groups the outer automorphism group has order 2. As another application, we construct Thompson-Stein groups which do not admit non trivial rep
RECURSIVELY RENEWABLE WORDS AND CODING OF IRRATIONAL ROTATIONS
Akiyama, Shigeki
RECURSIVELY RENEWABLE WORDS AND CODING OF IRRATIONAL ROTATIONS SHIGEKI AKIYAMA AND MASAYUKI us come back to a general A = {0, 1, . . . , m - 1}. An element z = z0z1 · · · AN is k-renewable is called recursively k-renewable. To be more precise, z = z0z1 . . . is recursively k- renewable when
Vortices in rotating systems: Centrifugal, elliptic and hyperbolic type instabilities
Lauga, Eric
Vortices in rotating systems: Centrifugal, elliptic and hyperbolic type instabilities D. Sipp, E and centrifugal instabilities. A complete picture of the short-wave stability properties of the flow is given that anticyclones undergo centrifugal instability if the Rossby number verifies Ro 1, elliptic instability for all
Physica D xxx (2004) xxxxxx Nonextensive statistical mechanics for rotating
Aubert, Julien
2004-01-01T23:59:59.000Z
Physica D xxx (2004) xxxxxx Nonextensive statistical mechanics for rotating quasi by Elsevier B.V. doi:10.1016/j.physd.2004.01.035 #12;2 S. Jung et al. / Physica D xxx (2004) xxxxxx been
Dissipative accretion flows around a rotating black hole
Santabrata Das; Sandip K. Chakrabarti
2008-06-12T23:59:59.000Z
We study the dynamical structure of a cooling dominated rotating accretion flow around a spinning black hole. We show that non-linear phenomena such as shock waves can be studied in terms of only three flow parameters, namely, the specific energy (${\\cal E}$), the specific angular momentum ($\\lambda$) and the accretion rate (${\\dot m}$) of the flow. We present all possible accretion solutions. We find that a significant region of the parameter space in the ${\\cal E}-\\lambda$ plane allows global accretion shock solutions. The effective area of the parameter space for which the Rankine-Hugoniot shocks are possible is maximum when the flow is dissipation free. It decreases with the increase of cooling effects and finally disappears when the cooling is high enough. We show that shock forms further away when the black hole is rotating compared to the solution around a Schwarzschild black hole with identical flow parameters at a large distance. However, in a normalized sense, the flow parameters for which the shocks form around the rotating black holes are produced shocks closer to the hole. The location of the shock is also dictated by the cooling efficiency in that higher the accretion rate (${\\dot m}$), the closer is the shock location. We believe that some of the high frequency quasi-periodic oscillations may be due to the flows with higher accretion rate around the rotating black holes.
Particle Acceleration in Rotating Modified Hayward and Bardeen Black Holes
Behnam Pourhassan; Ujjal Debnath
2015-06-10T23:59:59.000Z
In this paper we consider rotating modified Hayward and Bardeen black holes as particle accelerators. We investigate the the center of mass energy of two colliding neutral particles with same rest masses falling from rest at infinity to near the horizons of the mentioned black holes. We also investigate the range of the particle's angular momentum and the orbit of the particle.
Particle Acceleration in Rotating Modified Hayward and Bardeen Black Holes
Pourhassan, Behnam
2015-01-01T23:59:59.000Z
In this paper we consider rotating modified Hayward and Bardeen black holes as particle accelerators. We investigate the the center of mass energy of two colliding neutral particles with same rest masses falling from rest at infinity to near the horizons of the mentioned black holes. We also investigate the range of the particle's angular momentum and the orbit of the particle.
The Stability of Magnetized Rotating Plasmas with Superthermal Fields
Martin E. Pessah; Dimitrios Psaltis
2005-04-13T23:59:59.000Z
During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper, we investigate the local linear stability of differentially rotating, magnetized flows and the evolution of the magnetorotational instability beyond the weak-field limit. We show that, when superthermal toroidal fields are considered, the effects of both compressibility and magnetic tension forces, which are related to the curvature of toroidal field lines, should be taken fully into account. We demonstrate that the presence of a strong toroidal component in the magnetic field plays a non-trivial role. When strong fields are considered, the strength of the toroidal magnetic field not only modifies the growth rates of the unstable modes but also determines which modes are subject to instabilities. We find that, for rotating configurations with Keplerian laws, the magnetorotational instability is stabilized at low wavenumbers for toroidal Alfven speeds exceeding the geometric mean of the sound speed and the rotational speed. We discuss the significance of our findings for the stability of cold, magnetically dominated, rotating fluids and argue that, for these systems, the curvature of toroidal field lines cannot be neglected even when short wavelength perturbations are considered. We also comment on the implications of our results for the validity of shearing box simulations in which superthermal toroidal fields are generated.
PROOF COPY 504409PHF Standing shocks in a rotating channel
Tabak, Esteban G.
input from wind stress with energy dissipation at shocks. All the energy dissipation must be by means Street, New York, New York 10012 (Received 5 June 2003; accepted 15 June 2004) This paper discusses the stationary shallow water shocks occurring in a reentrant rotating channel with wind stress and topography
Sunspot rotation. I. A consequence of flux emergence
Sturrock, Z; Archontis, V; McNeill, C M
2015-01-01T23:59:59.000Z
Context. Solar eruptions and high flare activity often accompany the rapid rotation of sunspots. The study of sunspot rotation and the mechanisms driving this motion are therefore key to our understanding of how the solar atmosphere attains the conditions necessary for large energy release. Aims. We aim to demonstrate and investigate the rotation of sunspots in a 3D numerical experiment of the emergence of a magnetic flux tube as it rises through the solar interior and emerges into the atmosphere. Furthermore, we seek to show that the sub-photospheric twist stored in the interior is injected into the solar atmosphere by means of a definitive rotation of the sunspots. Methods. A numerical experiment is performed to solve the 3D resistive magnetohydrodynamic (MHD) equations using a Lagrangian-Remap code. We track the emergence of a toroidal flux tube as it rises through the solar interior and emerges into the atmosphere investigating various quantities related to both the magnetic field and plasma. Results. Thr...
Flow Separation Control with Rotating Cylinders James Schulmeister
(February 2001): 291-326. Goal: Control flow separation to reduce hydrodynamic drag and oscillating lift layer flow of the main cylinder. This delays flow separation and reduces drag. The control effortFlow Separation Control with Rotating Cylinders James Schulmeister Dr. Jason Dahl Prof. Michael
Charged fermions tunneling from accelerating and rotating black holes
Rehman, Mudassar; Saifullah, K., E-mail: mudassir051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)
2011-03-01T23:59:59.000Z
We study Hawking radiation of charged fermions from accelerating and rotating black holes with electric and magnetic charges. We calculate the tunneling probabilities of incoming and outgoing fermionic particles and find the Hawking temperature of these black holes. We also provide an explicit expression of the classical action for the massive and massless particles in the background of these black holes.
Stellar Rotation Proceedings IAU Symposium No. 215, c 2003 IAU
Owocki, Stanley P.
magnetic confine- ment parameter', (= B2 eqR2 / Mv), which characterizes the ratio between magnetic field magnetic confinement parameter', (= B2 eqR2 / Mv), which characterizes the ratio between magnetic field. The Effects of Field-Aligned Rotation on the Magnetically Channeled Line-Driven Winds Asif ud-Doula Department
Motor processes 1 Motor Processes in Mental Rotation1
Paris-Sud XI, Université de
Motor processes 1 Motor Processes in Mental Rotation1 1 M.W. wishes to thank the LPPA for its are at least in part guided by motor processes, even in the case of images of abstract objects rather than of a specific motor action. We directly test the hypothesis by means of a dual-task paradigm in which subjects
Dual periodicities in the rotational modulation of Saturn narrowband emissions
Gurnett, Donald A.
Dual periodicities in the rotational modulation of Saturn narrowband emissions S.Y. Ye,1 D. A emissions is examined, restricting the spacecraft location to either the northern or the southern hemisphere of Saturn. It is found that in both hemispheres, the modulation period of 5 kHz narrowband emissions has two
Anisotropic constraints on energy distribution in rotating and stratified turbulence
Kurien, Susan
OFFPRINT Anisotropic constraints on energy distribution in rotating and stratified turbulence S) 24003 www.epljournal.org doi: 10.1209/0295-5075/84/24003 Anisotropic constraints on energy distribution enstrophy constrains the spectral distribution of horizontal kinetic energy and potential energy. Horizontal
Self-Calibration from Multiple Views with a Rotating Camera
Hartley, Richard
Self-Calibration from Multiple Views with a Rotating Camera Richard I. Hartley G.E. CRD, Schenectady, NY, 12301. Email : hartley@crd.ge.com Abstract. A new practical method is given for the self-calibration orientations of the camera and calibration is computed from an analysis of point matches between the images
44-88 MHz transverse optics for the rotation section
McDonald, Kirk
44-88 MHz transverse optics for the rotation section G. Prior 02/02/2010 #12;Finding TwissBz/dz non-zero. #12;SOL model 1 (2/2) Identify the transfer map elements to the Twiss parameters
INTERNAL ROTATION AND DYNAMICS OF THE SUN FROM GONG DATA
Corbard, Thierry
for the Sun's internal rotation from GONG months 4--10 averaged power spectra. 1 In keeping by the Big Bear Solar Observatory, High Altitude Obseratory, Learmonth Solor Observatory, Udaipur Solor (GONG months 4--10) power spectra. One set comprises individual m frequencies from the GONG project
On the multipole moments of a rigidly rotating fluid body
Robert Filter; Andreas Kleinwächter
2009-02-11T23:59:59.000Z
Based on numerical simulations and analytical calculations we formulate a new conjecture concerning the multipole moments of a rigidly rotating fluid body in equilibrium. The conjecture implies that the exterior region of such a fluid is not described by the Kerr metric.
THE INFLUENCE OF EMOTIONAL CUES ON MENTAL ROTATION ABILITY
Amlani, Farah 1989-
2012-04-27T23:59:59.000Z
or threat condition. All participants completed a WASI IQ test for a standard measure of general intelligence and a mental rotation task that was presented on a computer monitor. For participants in the neutral condition, a neutral male face preceded each...
Rotation-reversal symmetries in crystals and handed structures
Gopalan, Venkatraman
: List of roto point groups indicated in Figure 2b that are invariance groups of a net (non-zero) spin (S of roto point groups indicated in Figure 2b that are invariance groups of non-zero (net) spin (S), non-zero (net) electric polarization (P), non-zero (net) static rotation (), and combinations thereof. Net Spin
Vibration-Based Damage Detection in Rotating Machinery
Farrar, C.R.; Duffey, T.A.
1999-06-28T23:59:59.000Z
Damage detection as determined from changes in the vibration characteristics of a system has been a popular research topic for the last thirty years. Numerous damage identification algorithms have been proposed for detecting and locating damage in structural and mechanical systems. To date, these damage-detection methods have shown mixed results. A particular application of vibration-based damage detection that has perhaps enjoyed the greatest success is that of damage detection in rotating machinery. This paper summarizes the state of technology in vibration-based damage detection applied to rotating machinery. The review interprets the damage detection process in terms of a statistical pattern recognition paradigm that encompasses all vibration-based damage detection methods and applications. The motivation for the study reported herein is to identify the reasons that vibration-based damage detection has been successfully applied to rotating machinery, but has yet to show robust applications to civil engineering infrastructure. The paper concludes by comparing and contrasting the vibration-based damage detection applied to rotating machinery with large civil engineering infrastructure applications.
Solar Rotation Effects on the Thermospheres of Mars and Earth
Forbes, Jeffrey
Solar Rotation Effects on the Thermospheres of Mars and Earth Jeffrey M. Forbes,1 * Sean Bruinsma,2 Frank G. Lemoine3 The responses of Earth's and Mars' thermospheres to the quasi-periodic (27-day is twice as large for Earth as for Mars. Per typical 20-unit change in 10.7-centimeter radio flux (used
Influence of Rotations on the Critical State of Soil Mechanics
Oquendo, W F; Lizcano, A
2010-01-01T23:59:59.000Z
The ability of grains to rotate can play a crucial role on the collective behavior of granular media. It has been observed in computer simulations that imposing a torque at the contacts modifies the force chains, making support chains less important. In this work we investigate the effect of a gradual hindering of the grains rotations on the so-called critical state of soil mechanics. The critical state is an asymptotic state independent of the initial solid fraction where deformations occur at a constant shear strength and compactness. We quantify the difficulty to rotate by a friction coefficient at the level of particles, acting like a threshold. We explore the effect of this particle-level friction coefficient on the critical state by means of molecular dynamics simulations of a simple shear test on a poly-disperse sphere packing. We found that the larger the difficulty to rotate, the larger the final shear strength of the sample. Other micro-mechanical variables, like the structural anisotropy and the di...
Oscillatory jets and instabilities in a rotating cylinder Yohann Dugueta
Paris-Sud XI, Université de
oscillatory jets/shear layers of fixed conical shape and can be interpreted in terms of the propagation and planetary cores, where they are spawned by boundary layer eruptions at criti- cal latitudes.16 The steady rotation of the boundaries17 and emanating from velocity discontinuities. These steady layers result from
grqc/9904009 Nonlinear Evolution of Rotating Relativistic Stars
Kokkotas, Kostas D.
]. When the neutron star has cooled to #12; 2 about 10 10 K after its formation, it can be subjectamplitude oscillations, which are in excellent agreement with linear normal mode frequencies computed in the Cowling approximation. As a first application of our code, quasiradial modes of rapidly rotating relativistic stars
Solar differential rotation and properties of magnetic clouds
K. Georgieva; B. Kirov; E. Gavruseva; J. Javaraiah
2005-11-09T23:59:59.000Z
The most geoeffective solar drivers are magnetic clouds - a subclass of coronal mass ejections (CME's) distinguished by the smooth rotation of the magnetic field inside the structure. The portion of CME's that are magnetic clouds is maximum at sunspot minimum and mimimum at sunspot maximum. This portion is determined by the amount of helicity carried away by CME's which in turn depends on the amount of helicity transferred from the solar interior to the surface, and on the surface differential rotation. The latter can increase or reduce, or even reverse the twist of emerging magnetic flux tubes, thus increasing or reducing the helicity in the corona, or leading to the violation of the hemispheric helicity rule, respectively. We investigate the CME's associated with the major geomagnetic storms in the last solar cycle whose solar sources have been identified, and find that in 10 out of 12 cases of violation of the hemispheric helicity rule or of highly geoeffective CME's with no magnetic field rotation, they originate from regions with "anti-solar" type of surface differential rotation.
The solar interior - radial structure, rotation, solar activity cycle
Axel Brandenburg
2007-03-28T23:59:59.000Z
Some basic properties of the solar convection zone are considered and the use of helioseismology as an observational tool to determine its depth and internal angular velocity is discussed. Aspects of solar magnetism are described and explained in the framework of dynamo theory. The main focus is on mean field theories for the Sun's magnetic field and its differential rotation.
The Balance of Dark and Luminous Mass in Rotating Galaxies
Stacy McGaugh
2005-09-12T23:59:59.000Z
A fine balance between dark and baryonic mass is observed in spiral galaxies. As the contribution of the baryons to the total rotation velocity increases, the contribution of the dark matter decreases by a compensating amount. This poses a fine-tuning problem for \\LCDM galaxy formation models, and may point to new physics for dark matter particles or even a modification of gravity.
Faraday rotation data analysis with least-squares elliptical fitting
White, Adam D.; McHale, G. Brent; Goerz, David A.; Speer, Ron D. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
2010-10-15T23:59:59.000Z
A method of analyzing Faraday rotation data from pulsed magnetic field measurements is described. The method uses direct least-squares elliptical fitting to measured data. The least-squares fit conic parameters are used to rotate, translate, and rescale the measured data. Interpretation of the transformed data provides improved accuracy and time-resolution characteristics compared with many existing methods of analyzing Faraday rotation data. The method is especially useful when linear birefringence is present at the input or output of the sensing medium, or when the relative angle of the polarizers used in analysis is not aligned with precision; under these circumstances the method is shown to return the analytically correct input signal. The method may be pertinent to other applications where analysis of Lissajous figures is required, such as the velocity interferometer system for any reflector (VISAR) diagnostics. The entire algorithm is fully automated and requires no user interaction. An example of algorithm execution is shown, using data from a fiber-based Faraday rotation sensor on a capacitive discharge experiment.
ROTATION OF WHITE LIGHT CME STRUCTURES AS INFERRED FROM
Solar Observatory 40386 North Shore Lane, Big Bear City, CA 92314 Valentyna Abramenko Big Bear Solar, Wilberforce Road, Cambridge CB30WA, UK ABSTRACT Understanding the connection between the magnetic that there is a slight preference for the CMEs to rotate toward the solar equator and heliospheric current sheet (59
Magee, Derek
with recovery of the rotational component. The core of the presented method is a custom spatial transform which on a reference image, which provides the criteria for movement com- pensation during transform optimisation with the Stack Alignment Transform in Cardiac MR Series Constantine Zakkaroff1 mnkz@leeds.ac.uk Aleksandra
Jet impingement heat transfer in two-pass rotating rectangular channels
Zhang, Yuming
1996-01-01T23:59:59.000Z
The combined effects of rotation and jet impingement on local heat transfer in a two-pass rotating rectangular channel is studied. The results of an experimental investigation on the surface heat transfer coefficients under a perforated plate...
Patterns of convection in rotating spherical R Simitev and F H Busse
Simitev, Radostin D
Patterns of convection in rotating spherical shells R Simitev and F H Busse Institute of Physics of rotating spherical shells. For recent reviews we refer to the papers by Zhang and Busse [23] and Busse [6
A Molecular Switch Based on Current-Driven Rotation of an Encapsulated...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Switch Based on Current-Driven Rotation of an Encapsulated Cluster within a Fullerene Cage. A Molecular Switch Based on Current-Driven Rotation of an Encapsulated Cluster within a...
A Multi-State Single-Molecule Switch Actuated by Rotation of...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Multi-State Single-Molecule Switch Actuated by Rotation of an Encapsulated Cluster within a Fullerene Cage. A Multi-State Single-Molecule Switch Actuated by Rotation of an...
Ferrofluid spin-up flows from uniform and non-uniform rotating magnetic fields
Khushrushahi, Shahriar Rohinton
2010-01-01T23:59:59.000Z
When ferrofluid in a cylindrical container is subjected to a rotating azimuthally directed magnetic field, the fluid "spins up" into an almost rigid-body rotation where ferrofluid nanoparticles have both a linear and an ...
System for automatically aligning a support roller system under a rotating body
Singletary, B. Huston (Oak Ridge, TN)
1983-01-01T23:59:59.000Z
Two support rings on a rotatable drum respectively engage conically tapered nd surfaces of support rollers mounted on pivot universally relative to its axis of rotation and translate therealong. Rotation of the drum on differential conical support roller diameters causes pivotal steering and axial translation of support roller until roller is centered on support rings.
System for automatically aligning a support roller system under a rotating body
Singletary, B.H.
1982-07-21T23:59:59.000Z
Two support rings on a rotatable drum respectively engage conically tapered end surfaces of support rollers mounted on pivot universally relative to its axis of rotation and translate therealong. Rotation of the drum on differential conical support roller diameters causes pivotal steering and axial translation of support roller until roller is centered on support rings.
Bifurcated states of a rotating tokamak plasma in the presence of a static error-field
Fitzpatrick, Richard
Bifurcated states of a rotating tokamak plasma in the presence of a static error-field Richard, Texas 78712 Received 20 January 1998; accepted 1 June 1998 The bifurcated states of a rotating tokamak without hindrance. The response regime of a rotating tokamak plasma in the vicinity of the rational
Vibration-rotation coupling in a Morse oscillator C. E. Burkhardta
Leventhal, Jacob J.
Vibration-rotation coupling in a Morse oscillator C. E. Burkhardta Department of Physics, St. Louis 2007; accepted 25 May 2007 The Morse function is invaluable for describing the vibrational motion for this potential only if molecular rotation is ignored or if the rotation is isolated from the vibrational motion
Channeling in a Rotating Plasma Abraham J. Fetterman and Nathaniel J. Fisch
energy, in addition to amplifying the rf waves, can directly enhance the rotation energy which in turn at the rotation velocity in the rotating frame. Lately there has been a renewed interest in this effect [4 is that in a deuterium-tritium cen- trifugal fusion reactor, the energy of particles, the by- products of the fusion
Dissipative dark matter and the rotation curves of dwarf galaxies
Foot, R
2015-01-01T23:59:59.000Z
There is ample evidence from rotation curves that dark matter halo's around disk galaxies have nontrivial dynamics. Of particular significance are: a) the cored dark matter profile of disk galaxies, b) correlations of the shape of rotation curves with baryonic properties, and c) the Tully-Fisher relation. Dark matter halo's around disk galaxies may have nontrivial dynamics if dark matter is strongly self interacting and dissipative. Multicomponent hidden sector dark matter featuring a massless `dark photon' (from an unbroken dark $U(1)$ gauge interaction) which kinetically mixes with the ordinary photon provides a concrete example of such dark matter. The kinetic mixing interaction facilitates halo heating by enabling ordinary supernovae to be a source of these `dark photons'. Dark matter halo's can expand and contract in response to the heating and cooling processes, but for a sufficiently isolated halo should have evolved to a steady state or `equilibrium' configuration where heating and cooling rates local...
Cooling Flows of Self-Gravitating, Rotating, Viscous Systems
Mohsen Shadmehri; Jamshid Ghanbari
2002-04-06T23:59:59.000Z
We obtain self-similar solutions that describe the dynamics of a self-gravitating, rotating, viscous system. We use simplifying assumptions; but explicitly include viscosity and the cooling due to the dissipation of energy. By assuming that the turbulent dissipation of energy is as power law of the density and the speed v_{rms} and for a power-law dependence of viscosity on the density, pressure, and rotational velocity, we investigate turbulent cooling flows. It has been shown that for the cylindrically and the spherically cooling flows the similarity indices are the same, and they depend only on the exponents of the dissipation rate and the viscosity model. Depending on the values of the exponents, which the mechanisms of the dissipation and viscosity determine them, we may have solutions with different general physical properties. The conservation of the total mass and the angular momentum of the system strongly depends on the mechanisms of energy dissipation and the viscosity model.
PIC simulation of electrodeless plasma thruster with rotating electric field
Nomura, Ryosuke; Ohnishi, Naofumi; Nishida, Hiroyuki [Department of Aerospace Engineering, Tohoku University, Sendai 980-8579 (Japan); Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588 (Japan)
2012-11-27T23:59:59.000Z
For longer lifetime of electric propulsion system, an electrodeless plasma thruster with rotating electric field have been proposed utilizing a helicon plasma source. The rotating electric field may produce so-called Lissajous acceleration of helicon plasma in the presence of diverging magnetic field through a complicated mechanism originating from many parameters. Two-dimensional simulations of the Lissajous acceleration were conducted by a code based on Particle-In-Cell (PIC) method and Monte Carlo Collision (MCC) method for understanding plasma motion in acceleration area and for finding the optimal condition. Obtained results show that azimuthal current depends on ratio of electron drift radius to plasma region length, AC frequency, and axial magnetic field. When ratio of cyclotron frequency to the AC frequency is higher than unity, reduction of the azimuthal current by collision effect is little or nothing.
Rotating BTZ Black Holes and One Dimensional Holographic Superconductors
Pankaj Chaturvedi; Gautam Sengupta
2014-06-30T23:59:59.000Z
We consider charged rotating BTZ black holes in 2+1 dimensions and obtain 1+1 dimensional holographic superconductors on a spatial circle in the context of the $AdS_3/CFT_2$ correspondence. The charged condensate for the boundary superconductor is computed both in the analytic and the numerical framework in a probe limit and a low angular momentum approximation. A critical value of the angular momentum for the onset of superconductivity is established. We also numerically compute the electrical conductivity of the 1+1 dimensional boundary theory on a circle. The conductivity exhibits a dependence on angular momentum of the rotating black hole both for the normal and the superconducting phase of the boundary field theory. The significance of the boundary field theory in the context of a Fermi-Luttinger liquid on a circle is discussed.
Design of Energy Scavengers Mounted on Rotating Shafts
Shahruz, S M
2008-01-01T23:59:59.000Z
In this paper, a novel energy scavenger is proposed. The scavenger consists of a cantilever beam on which piezoelectric films and a mass are mounted. The mass at the tip of the beam is known as the proof mass and the device is called either an energy scavenger or a beam-mass system. The beam-mass system is mounted on a rotating shaft, where the axis of the shaft is horizontal. A single-degree-of-freedom (SDOF) mathematical model is derived for the scavenger and its properties are carefully examined. From the model, it becomes clear that the rotation of the shaft and gravity cause both parametric excitations and exogenous forces which make the beam-mass system vibrate. Guidelines are provided as how to choose the scavenger parameters in order to have it resonate. Examples are given to illustrate the performance of the proposed scavenger.
The Stability of Magnetized Rotating Plasmas with Superthermal Fields
Pessah, M E
2004-01-01T23:59:59.000Z
During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper, we investigate the local linear stability of differentially rotating, magnetized flows and the evolution of the magnetorotational instability beyond the weak-field limit. We show that, when superthermal toroidal fields are considered, both compressibility and magnetic tension terms, related to the curvature of toroidal field lines, should be taken fully into account. We demonstrate that, contrary to the results of most previous investigations, the presence of a toroidal component in the magnetic field plays a crucial role not only in the growth rates of the unstable modes but also in determining which modes are subject to instabilities. We find that, for rotationally supported configurations, the magnetorotational instability is stabilized at low wavenumbers for toroidal Alfven sp...
On the black hole limit of rotating discs and rings
Andreas Kleinwächter; Hendrick Labranche; Reinhard Meinel
2010-07-20T23:59:59.000Z
Solutions to Einstein's field equations describing rotating fluid bodies in equilibrium permit parametric (i.e. quasi-stationary) transitions to the extreme Kerr solution (outside the horizon). This has been shown analytically for discs of dust and numerically for ring solutions with various equations of state. From the exterior point of view, this transition can be interpreted as a (quasi) black hole limit. All gravitational multipole moments assume precisely the values of an extremal Kerr black hole in the limit. In the present paper, the way in which the black hole limit is approached is investigated in more detail by means of a parametric Taylor series expansion of the exact solution describing a rigidly rotating disc of dust. Combined with numerical calculations for ring solutions our results indicate an interesting universal behaviour of the multipole moments near the black hole limit.
Three-Hair Relations for Rotating Stars: Nonrelativistic Limit
Leo C. Stein; Kent Yagi; Nicolas Yunes
2014-05-17T23:59:59.000Z
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.
Quantum optimal control within the rotating wave approximation
Maximilian Keck; Matthias M. Müller; Tommaso Calarco; Simone Montangero
2015-03-06T23:59:59.000Z
We study the interplay between rotating wave approximation and optimal control. In particular, we show that for a wide class of optimal control problems one can choose the control field such that the Hamiltonian becomes time-independent under the rotating wave approximation. Thus, we show how to recast the functional minimization defined by the optimal control problem into a simpler multi-variable function minimization. We provide the analytic solution to the state-to-state transfer of the paradigmatic two-level system and to the more general star configuration of an $N$-level system. We demonstrate numerically the usefulness of this approach in the more general class of connected acyclic $N$-level systems with random spectra. Finally, we use it to design a protocol to entangle Rydberg via constant laser pulses atoms in an experimentally relevant range of parameters.
Electron beam machining using rotating and shaped beam power distribution
Elmer, J.W.; O`Brien, D.W.
1996-07-09T23:59:59.000Z
An apparatus and method are disclosed for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: (1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and (2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1,000 {micro}m (1 mm or larger), compared to the 250 {micro}m diameter of laser drilling. 5 figs.
Electron beam machining using rotating and shaped beam power distribution
Elmer, John W. (Pleasanton, CA); O'Brien, Dennis W. (Livermore, CA)
1996-01-01T23:59:59.000Z
An apparatus and method for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: 1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and 2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1000 .mu.m (1 mm or larger), compared to the 250 .mu.m diameter of laser drilling.
Thermodynamic geometry of charged rotating BTZ black holes
Akbar, M. [Center for Advanced Mathematics and Physics, National University of Sciences and Technology, H-12, Islamabad (Pakistan); Quevedo, H. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, AP 70543, Mexico, DF 04510 (Mexico); ICRANet, Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy); Saifullah, K. [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan); Sanchez, A. [Departamento de Posgrado, CIIDET, AP 752, Queretaro, QRO 76000 (Mexico); Taj, S. [Center for Advanced Mathematics and Physics, National University of Sciences and Technology, H-12, Islamabad (Pakistan); ICRANet, Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy)
2011-04-15T23:59:59.000Z
We study the thermodynamics and the thermodynamic geometries of charged rotating Banados-Teitelboim-Zanelli black holes in (2+1)-gravity. We investigate the thermodynamics of these systems within the context of the Weinhold and Ruppeiner thermodynamic geometries and the recently developed formalism of geometrothermodynamics. Considering the behavior of the heat capacity and the Hawking temperature, we show that Weinhold and Ruppeiner geometries cannot describe completely the thermodynamics of these black holes and of their limiting case of vanishing electric charge. In contrast, the Legendre invariance imposed on the metric in geometrothermodynamics allows one to describe the charged rotating Banados-Teitelboim-Zanelli black holes and their limiting cases in a consistent and invariant manner.
A high precision, compact electromechanical ground rotation sensor
Dergachev, V., E-mail: volodya@caltech.edu [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, California 91125 (United States); DeSalvo, R. [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, California 91125 (United States) [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, California 91125 (United States); University of Sannio, C.so Garibaldi 107, Benevento 82100 (Italy); Asadoor, M. [Mayfield Senior School, 500 Bellefontaine Street, Pasadena, California 91105 (United States) [Mayfield Senior School, 500 Bellefontaine Street, Pasadena, California 91105 (United States); Oklahoma State University, 219 Student Union, Stillwater, Oklahoma 74074 (United States); Bhawal, A. [Arcadia High School, 180 Campus Drive, Arcadia, California 91007 (United States) [Arcadia High School, 180 Campus Drive, Arcadia, California 91007 (United States); Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213 (United States); Gong, P. [Department of Precision Instrument, Tsinghua University, Beijing 100084 (China) [Department of Precision Instrument, Tsinghua University, Beijing 100084 (China); School of Industrial and System Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0205 (United States); Kim, C. [California Institute of Technology, Pasadena, California 91125 (United States)] [California Institute of Technology, Pasadena, California 91125 (United States); Lottarini, A. [Department of Computer Science, University of Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy) [Department of Computer Science, University of Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Department of Computer Science, Columbia University, 1214 Amsterdam Avenue, New York, New York 10027 (United States); Minenkov, Y. [Sezione INFN Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy)] [Sezione INFN Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Murphy, C. [School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, Western Australia 6009 (Australia) [School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, Western Australia 6009 (Australia); University of Melbourne Grattan Street, Parkville VIC 3010 (Australia); O'Toole, A. [University of California, Los Angeles, 405 Hilgard Ave, Los Angeles, California 90095 (United States) [University of California, Los Angeles, 405 Hilgard Ave, Los Angeles, California 90095 (United States); Michigan Technological University, 1400 Townsend Dr, Houghton, Michigan 49931 (United States); Peña Arellano, F. E. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); and others
2014-05-15T23:59:59.000Z
We present a mechanical rotation sensor consisting of a balance pivoting on a tungsten carbide knife edge. These sensors are important for precision seismic isolation systems, as employed in land-based gravitational wave interferometers and for the new field of rotational seismology. The position sensor used is an air-core linear variable differential transformer with a demonstrated noise floor of 1 × 10{sup ?11}m/?( Hz ). We describe the instrument construction and demonstrate low noise operation with a noise floor upper bound of 5.7 × 10{sup ?9} rad /?( Hz ) at 10 mHz and 6.4 × 10{sup ?10} rad /?( Hz ) at 0.1 Hz. The performance of the knife edge hinge is compatible with a behaviorur free of noise from dislocation self-organized criticality.
Rotational quenching of CO due to H$_2$ collisions
Yang, Benhui; Balakrishnan, N; Forrey, R C
2010-01-01T23:59:59.000Z
Rate coefficients for state-to-state rotational transitions in CO induced by both para- and ortho-H$_2$ collisions are presented. The results were obtained using the close-coupling method and the coupled-states approximation, with the CO-H$_2$ interaction potential of Jankowski & Szalewicz (2005). Rate coefficients are presented for temperatures between 1 and 3000 K, and for CO($v=0,j$) quenching from $j=1-40$ to all lower $j^\\prime$ levels. Comparisons with previous calculations using an earlier potential show some discrepancies, especially at low temperatures and for rotational transitions involving large $|\\Delta j|$. The differences in the well depths of the van der Waals interactions in the two potential surfaces lead to different resonance structures in the energy dependence of the cross sections which influence the low temperature rate coefficients. Applications to far infrared observations of astrophysical environments are briefly discussed.
Magnetic Field Rotations in the Solar Wind at Kinetic Scales
Chen, C H K; Burgess, D; Horbury, T S
2015-01-01T23:59:59.000Z
The solar wind magnetic field contains rotations at a broad range of scales, which have been extensively studied in the MHD range. Here we present an extension of this analysis to the range between ion and electron kinetic scales. The distribution of rotation angles was found to be approximately log-normal, shifting to smaller angles at smaller scales almost self-similarly, but with small, statistically significant changes of shape. The fraction of energy in fluctuations with angles larger than $\\alpha$ was found to drop approximately exponentially with $\\alpha$, with e-folding angle $9.8^\\circ$ at ion scales and $0.66^\\circ$ at electron scales, showing that large angles ($\\alpha > 30^\\circ$) do not contain a significant amount of energy at kinetic scales. Implications for kinetic turbulence theory and the dissipation of solar wind turbulence are discussed.
Possible Measurable Effects of Dark Energy in Rotating Superconductors
Clovis Jacinto de Matos; Christian Beck
2007-07-12T23:59:59.000Z
We discuss recent laboratory experiments with rotating superconductors and show that three so far unexplained experimentally observed effects (anomalous acceleration signals, anomalous gyroscope signals, Cooper pair mass excess) can be physically explained in terms of a possible interaction of dark energy with Cooper pairs. Our approach is based on a Ginzburg-Landau-like model of electromagnetic dark energy, where gravitationally active photons obtain mass in the superconductor. We show that this model can account simultaneously for the anomalous acceleration and anomalous gravitomagnetic fields around rotating superconductors measured by Tajmar et al. and for the anomalous Cooper pair mass in superconductive Niobium, measured by Cabrera and Tate. It is argued that these three different physical effects are ultimately different experimental manifestations of the simultaneous spontaneous breaking of gauge invariance, and of the principle of general covariance in superconductive materials.
Agmon, Noam
Hydrogen Bonds, Water Rotation and Proton Mobility Liaisons Hydrog`ene, Rotation de l'eau et H 3 O + est presque immoÂ bilis'e par des liaisons hydrog`ene extrâ??emement fortes. Ces derni liaisons hydrog`ene de l'eau pure. Dans l'eau en dessous de 20 0 C, la rotation des mol'ecules est plus
Nonlinear magneto-optic polarization rotation with intense laser fields
Hsu, Paul S.; Patnaik, Anil K.; Welch, George R.
2008-01-01T23:59:59.000Z
magneto-optic polarization rotation with intense laser fields Paul S. Hsu,1,*,? Anil K. Patnaik,1,2,? and George R. Welch1 1Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA 2Department of Physics, Wright State.... ?8,9? described a high-sensitivity optical magnetometer based on electromagnetically induced transparency ?EIT?, where the high dispersion at an EIT resonance can dramatically im- prove the sensitivity of magnetic field measurements by sup...
What is the optimum stellar rotation rate for a collapsar?
William H. Lee
2007-03-01T23:59:59.000Z
We consider low angular momentum, neutrino cooled accretion flows onto newborn black holes in the context of the collapsar model for long Gamma Ray Bursts, and find a considerable energy release for rotation rates lower than those usually considered. The efficiency for the transformation of gravitational binding energy into radiation is maximized when the equatorial angular momentum l0 ~ 2 Rg c, where Rg is the Schwarzschild radius.
A nonlinear calculation of rotating cavitation in inducers
Tsujimoto, Y.; Watanabe, S.; Yoshida, Y. [Osaka Univ., Osaka (Japan); Kamijo, K. [Kakuda Research Center (Japan). Rocket Propulsion Division
1994-12-31T23:59:59.000Z
In the previous linear analysis (Tsujimoto et al., 1993) it was found that there can be a backward rotating cavitation as well as a forward mode which rotates faster than impeller. Although some shaft vibration has been observed which might be caused by the backward mode, experimental evidence has been obtained only for the forward mode. The ultimate goal of the present study is to answer the question which mode of the cavitation instabilities -- cavitation surge and the two modes of rotating cavitation -- occurs in a given system and operating condition, and to find out analytical method to determine their amplitude. A time marching non-linear 2-D flow analysis was carried out for this purpose. It was found that the increase of cavitation compliance at lower inlet pressure can be a factor which limits the amplitude. The mode selectivity is mainly dependent on the stability limit obtained by a linear analysis for which the phase delay of cavity has a most important effect.
Rotational Rehybridization and the High Temperature Phase of UC2
Wen, Xiaodong; Rudin, Sven P.; Batista, Enrique R.; Clark, David L.; Scuseria, Gustavo E.; Martin, Richard L.
2012-12-03T23:59:59.000Z
The screened hybrid approximation (HSE) of density functional theory (DFT) is used to examine the structural, optical, and electronic properties of the high temperature phase, cubic UC(2). This phase contains C(2) units with a computed C-C distance of 1.443 Å which is in the range of a CC double bond; U is formally 4+, C(2) 4-. The closed shell paramagnetic state (NM) was found to lie lowest. Cubic UC(2) is found to be a semiconductor with a narrow gap, 0.4 eV. Interestingly, the C(2) units connecting two uranium sites can rotate freely up to an angle of 30°, indicating a hindered rotational solid. Ab-initio molecular dynamic simulations (HSE) show that the rotation of C(2) units in the low temperature phase (tetragonal UC(2)) occurs above 2000 K, in good agreement with experiment. The computed energy barrier for the phase transition from tetragonal UC(2) to cubic UC(2) is around 1.30 eV per UC(2). What is fascinating about this system is that at high temperature, the phase transformation to the cubic phase is associated with a rehybridization of the C atoms from sp to sp(3).
Particle acceleration in rotating and shearing jets from AGN
F. M. Rieger; K. Mannheim
2002-10-14T23:59:59.000Z
We model the acceleration of energetic particles due to shear and centrifugal effects in rotating astrophysical jets. The appropriate equation describing the diffusive transport of energetic particles in a collisionless, rotating background flow is derived and analytical steady state solutions are discussed. In particular, by considering velocity profiles from rigid, over flat to Keplerian rotation, the effects of centrifugal and shear acceleration of particles scattered by magnetic inhomogeneities are distinguished. In the case where shear acceleration dominates, it is confirmed that power law particle momentum solutions $f(p) \\propto p^{-(3+\\alpha)}$ exist, if the mean scattering time $\\tau_c \\propto p^{\\alpha}$ is an increasing function of momentum. We show that for a more complex interplay between shear and centrifugal acceleration, the recovered power law momentum spectra might be significantly steeper but flatten with increasing azimuthal velocity due to the increasing centrifugal effects. The possible relevance of shear and centrifugal acceleration for the observed extended emission in AGN is demonstrated for the case of the jet in the quasar 3C273.
Resonant Interactions in Rotating Homogeneous Three-dimensional Turbulence
Q. Chen; S. Chen; G. L. Eyink; D. D. Holm
2004-04-29T23:59:59.000Z
Direct numerical simulations of three-dimensional (3D) homogeneous turbulence under rapid rigid rotation are conducted to examine the predictions of resonant wave theory for both small Rossby number and large Reynolds number. The simulation results reveal that there is a clear inverse energy cascade to the large scales, as predicted by 2D Navier-Stokes equations for resonant interactions of slow modes. As the rotation rate increases, the vertically-averaged horizontal velocity field from 3D Navier-Stokes converges to the velocity field from 2D Navier-Stokes, as measured by the energy in their difference field. Likewise, the vertically-averaged vertical velocity from 3D Navier-Stokes converges to a solution of the 2D passive scalar equation. The energy flux directly into small wave numbers in the $k_z=0$ plane from non-resonant interactions decreases, while fast-mode energy concentrates closer to that plane. The simulations are consistent with an increasingly dominant role of resonant triads for more rapid rotation.
HOW CAN NEWLY BORN RAPIDLY ROTATING NEUTRON STARS BECOME MAGNETARS?
Cheng, Quan; Yu, Yun-Wei, E-mail: yuyw@mail.ccnu.edu.cn [Institute of Astrophysics, Central China Normal University, Wuhan 430079 (China)
2014-05-10T23:59:59.000Z
In a newly born (high-temperature and Keplerian rotating) neutron star, r-mode instability can lead to stellar differential rotation, which winds the seed poloidal magnetic field (?10{sup 11} G) to generate an ultra-high (?10{sup 17} G) toroidal field component. Subsequently, by succumbing to the Tayler instability, the toroidal field could be partially transformed into a new poloidal field. Through such dynamo processes, the newly born neutron star with sufficiently rapid rotation could become a magnetar on a timescale of ?10{sup 2} {sup –} {sup 3} s, with a surface dipolar magnetic field of ?10{sup 15} G. Accompanying the field amplification, the star could spin down to a period of ?5 ms through gravitational wave radiation due to the r-mode instability and, in particular, the non-axisymmetric stellar deformation caused by the toroidal field. This scenario provides a possible explanation for why the remnant neutron stars formed in gamma-ray bursts and superluminous supernovae could be millisecond magnetars.
CONFRONTING COLD DARK MATTER PREDICTIONS WITH OBSERVED GALAXY ROTATIONS
Obreschkow, Danail; Meyer, Martin; Power, Chris; Staveley-Smith, Lister [International Centre for Radio Astronomy Research (ICRAR), M468, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia)] [International Centre for Radio Astronomy Research (ICRAR), M468, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia); Ma, Xiangcheng [The University of Sciences and Technology of China, Centre for Astrophysics, Hefei, Anhui 230026 (China)] [The University of Sciences and Technology of China, Centre for Astrophysics, Hefei, Anhui 230026 (China); Zwaan, Martin [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching b. Muenchen (Germany)] [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching b. Muenchen (Germany); Drinkwater, Michael J. [School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072 (Australia)] [School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072 (Australia)
2013-04-01T23:59:59.000Z
The rich statistics of galaxy rotations as captured by the velocity function (VF) provide invaluable constraints on galactic baryon physics and the nature of dark matter (DM). However, the comparison of observed galaxy rotations against cosmological models is prone to subtle caveats that can easily lead to misinterpretations. Our analysis reveals full statistical consistency between {approx}5000 galaxy rotations, observed in line-of-sight projection, and predictions based on the standard cosmological model ({Lambda}CDM) at the mass-resolution of the Millennium simulation (H I line-based circular velocities above {approx}50 km s{sup -1}). Explicitly, the H I linewidths in the H I Parkes All Sky Survey (HIPASS) are found to be consistent with those in S{sup 3}-SAX, a post-processed semi-analytic model for the Millennium simulation. Previously found anomalies in the VF can be plausibly attributed to (1) the mass-limit of the Millennium simulation, (2) confused sources in HIPASS, (3) inaccurate inclination measurements for optically faint sources, and (4) the non-detectability of gas-poor early-type galaxies. These issues can be bypassed by comparing observations and models using linewidth source counts rather than VFs. We investigate if and how well such source counts can constrain the temperature of DM.
Rotating black holes, global symmetry and first order formalism
Laura Andrianopoli; Riccardo D'Auria; Paolo Giaccone; Mario Trigiante
2012-10-15T23:59:59.000Z
In this paper we consider axisymmetric black holes in supergravity and address the general issue of defining a first order description for them. The natural setting where to formulate the problem is the De Donder-Weyl-Hamilton-Jacobi theory associated with the effective two-dimensional sigma-model action describing the axisymmetric solutions. We write the general form of the two functions S_m defining the first-order equations for the fields. It is invariant under the global symmetry group G_(3) of the sigma-model. We also discuss the general properties of the solutions with respect to these global symmetries, showing that they can be encoded in two constant matrices belonging to the Lie algebra of G_(3), one being the Noether matrix of the sigma model, while the other is non-zero only for rotating solutions. These two matrices allow a G_(3)-invariant characterization of the rotational properties of the solution and of the extremality condition. We also comment on extremal, under-rotating solutions from this point of view.
Braking index of isolated uniformly rotating magnetized pulsars
Hamil, Oliver; Urbanec, Martin; Urbancova, Gabriela
2015-01-01T23:59:59.000Z
Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\\Omega$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate in detail, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of $\\Omega$. This relation leads to the power law $\\dot{\\Omega}$ = -K $\\Omega^{\\rm n}$ where $n$ is called the braking index. The MDR model predicts $n$ exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of $n$, individually accurate to a few percent or better, in the range 1$ <$ n $ < $ 2.8, which is consi...
Large-scale anisotropy in stably stratified rotating flows
Marino, Dr. Raffaele [National Center for Atmospheric Research (NCAR); Mininni, Dr. Pablo D. [Universidad de Buenos Aires, Argentina; Rosenberg, Duane L [ORNL; Pouquet, Dr. Annick [National Center for Atmospheric Research (NCAR)
2014-01-01T23:59:59.000Z
We present results from direct numerical simulations of the Boussinesq equations in the presence of rotation and/or stratification, both in the vertical direction. The runs are forced isotropically and randomly at small scales and have spatial resolutions of up to $1024^3$ grid points and Reynolds numbers of $\\approx 1000$. We first show that solutions with negative energy flux and inverse cascades develop in rotating turbulence, whether or not stratification is present. However, the purely stratified case is characterized instead by an early-time, highly anisotropic transfer to large scales with almost zero net isotropic energy flux. This is consistent with previous studies that observed the development of vertically sheared horizontal winds, although only at substantially later times. However, and unlike previous works, when sufficient scale separation is allowed between the forcing scale and the domain size, the total energy displays a perpendicular (horizontal) spectrum with power law behavior compatible with $\\sim k_\\perp^{-5/3}$, including in the absence of rotation. In this latter purely stratified case, such a spectrum is the result of a direct cascade of the energy contained in the large-scale horizontal wind, as is evidenced by a strong positive flux of energy in the parallel direction at all scales including the largest resolved scales.
Large rotating AdS black holes from fluid mechanics
Sayantani Bhattacharyya; Subhaneil Lahiri; R. Loganayagam; Shiraz Minwalla
2008-07-25T23:59:59.000Z
We use the AdS/CFT correspondence to argue that large rotating black holes in global AdS(D) spaces are dual to stationary solutions of the relativistic Navier-Stokes equations on S**(D-2). Reading off the equation of state of this fluid from the thermodynamics of non-rotating black holes, we proceed to construct the nonlinear spinning solutions of fluid mechanics that are dual to rotating black holes. In all known examples, the thermodynamics and the local stress tensor of our solutions are in precise agreement with the thermodynamics and boundary stress tensor of the spinning black holes. Our fluid dynamical description applies to large non-extremal black holes as well as a class of large non-supersymmetric extremal black holes, but is never valid for supersymmetric black holes. Our results yield predictions for the thermodynamics of all large black holes in all theories of gravity on AdS spaces, for example, string theory on AdS(5) x S**5 and M theory on AdS(4) x S**7 and AdS(7) x S**4.
Wind Circulation in Selected Rotating Magnetic Early-B Stars
Myron A. Smith; Detlef Groote
2001-04-03T23:59:59.000Z
The rotating magnetic B stars have oblique dipolar magnetic fields and often anomalous helium and metallic compositions. These stars develop co-rotating torus-shaped clouds by channelling winds from their magnetic poles to an anchored planar disk over the magnetic equator. The line absorptions from the cloud can be studied as the complex rotates and periodically occults the star. We describe an analysis of the clouds of four stars (HD184927, beta Cep, sigma Ori E, and HR6684). From line synthesis models, we find that the metallic compositions are spatially uniform over the stars' surfaces. Next, using the Hubeny CIRCUS code, we demonstate that periodic UV continuum fluxes can be explained by the absorption of low-excitation lines. The analysis also quantifies the cloud temperatures, densities, and turbulences, which appear to increase inward toward the stars. The temperatures range from about 12,000K for the weak Fe lines up to temperatures of 33,000K for N V absorptions, which is in excess of temperatures expected from radiative equilibrium. The spectroscopic hallmark of this stellar class is the presence of strong C IV and N V resonance line absorptions at occultation phases and of redshifted emissions at magnetic pole-on phases. The emissions have characteristics which seem most compatible with the generation of high-energy shocks at the wind-cloud interface, as predicted by Babel.
Fiber-Optic-Gyroscope Measurements Close to Rotating Liquid Helium
M. Tajmar; F. Plesescu
2009-11-05T23:59:59.000Z
We previously reported anomalous fiber-optic gyroscope signals observed above rotating rings at temperatures close to liquid helium. Our results suggested that the liquid helium itself may be the source of our observed phenomenon. We constructed a new cryostat experiment that allows rotating a large quantity of liquid helium together with a superconducting niobium tube. The facility is built in such a way that our gyroscope can be placed directly in the center of rotation along the axis; however, the cryostat is built around the gyroscope to allow measuring without interference of helium liquid or gas. An anomalous signal was found of similar value compared to our previous measurements with a changed sign. As this measurement was done at a different location (center position) with respect to our old setup (top position), first hints for a possible field distribution of this phenomenon can be made. However, due to lower angular velocities used in this new setup so far, our measurement resolution was close to three times the resolution of our gyroscope and hence our data represent work in progress.
Goupil, M J; Marques, J P; Ouazzani, R M; Belkacem, K; Lebreton, Y; Samadi, R
2012-01-01T23:59:59.000Z
Asteroseismology with the space-borne missions CoRoT and Kepler provides a powerful mean of testing the modeling of transport processes in stars. Rotational splittings are currently measured for a large number of red giant stars and can provide stringent constraints on the rotation profiles. The aim of this paper is to obtain a theoretical framework for understanding the properties of the observed rotational splittings of red giant stars with slowly rotating cores. This allows us to establish appropriate seismic diagnostics for rotation of these evolved stars. Rotational splittings for stochastically excited dipolar modes are computed adopting a first-order perturbative approach for two $1.3 M_\\odot$ benchmark models assuming slowly rotating cores. For red giant stars with slowly rotating cores, we show that the variation of the rotational splittings of $\\ell=1$ modes with frequency depends only on the large frequency separation, the g-mode period spacing, and the ratio of the average envelope to core rotatio...
Yang, Benhui; Balakrishnan, N; Forrey, R C; Bowman, J M
2013-01-01T23:59:59.000Z
New quantum scattering calculations for rotational deexcitation transitions of CO induced by H collisions using two CO-H potential energy surfaces (PESs) from Shepler et al. (2007) are reported. State-to-state rate coefficients are computed for temperatures ranging from 1 to 3000 K for CO($v=0,j$) deexcitation from $j=1-5$ to all lower $j^\\prime$ levels, with $j$ being the rotational quantum number. Different resonance structures in the cross sections are attributed to the differences in the anisotropy and the long-range van der Waals well depths of the two PESs. These differences affect rate coefficients at low temperatures and give an indication of the uncertainty of the results. Significant discrepancies are found between the current rate coefficients and previous results computed using earlier potentials, while the current results satisfy expected propensity rules. Astrophysical applications to modeling far infrared and submillimeter observations are briefly discussed.
Seismic modelling of the rotating, slowly pulsating B-type star HD 21071
Szewczuk, Wojciech
2015-01-01T23:59:59.000Z
Interpretation of the oscillation spectrum of the slowly pulsating B-type star HD21071 is presented. We show that non-rotating models cannot account for the two highest amplitude frequencies and taking into account the effects of rotation is necessary. Rotating seismic models are constructed using various chemical compositions, opacity data, core overshooting parameters and rotational velocities. There are prospects for seismic modelling of SPB stars, even if no asymptotic pattern is observed in their oscillation spectra, provided an unambiguous mode identification is doable and the effects of rotation are properly included.
Fermi coordinates and modified Franklin transformation : A comparative study on rotational phenomena
M. Nouri-Zonoz; H. Ramezani-Aval
2014-12-18T23:59:59.000Z
Employing a relativistic rotational transformation to study and analyze rotational phenomena, instead of the rotational transformations based on consecutive Lorentz transformations and Fermi coordinates, leads to different predictions. In this article, after a comparative study between Fermi metric of a uniformly rotating eccentric observer and the spacetime metric in the same observer's frame obtained through the modified Franklin transformation, we consider rotational phenomena including transverse Doppler effect and Sagnac effect in both formalisms and compare their predictions. We also discuss length measurements in the two formalisms.
Spin-rotation contribution to the relaxation time of the fluorine nuclei in benzotrifluoride
Faulk, Robert Hardy
1965-01-01T23:59:59.000Z
to calculate the correlation time, the 6 5 3 dipole-dipole and spin-rotation contributions to the relaxation time of the fluorine have been separated. An effective spin-rotation coupling constant has been calculated from the spin-rotation contribution... theory of Bloem- bergen, Purcell and Pound. ' The contribution to the relaxation process due to spin-rotation interaction is calculated on the basis of the work of Hubbard. Al ';ough Hubbard calculated the effect of the spin-rotation interaction...
Emergence of rotational bands in ab initio no-core configuration interaction calculations
M. A. Caprio; P. Maris; J. P. Vary; R. Smith
2015-02-04T23:59:59.000Z
Rotational bands have been observed to emerge in ab initio no-core configuration interaction (NCCI) calculations for p-shell nuclei, as evidenced by rotational patterns for excitation energies, electromagnetic moments, and electromagnetic transitions. We investigate the ab initio emergence of nuclear rotation in the Be isotopes, focusing on 9Be for illustration, and make use of basis extrapolation methods to obtain ab initio predictions of rotational band parameters for comparison with experiment. We find robust signatures for rotational motion, which reproduce both qualitative and quantitative features of the experimentally observed bands.
Miura, Shinichi [Institute for Molecular Science, 38 Myodaiji, Okazaki 444-8585 (Japan)
2007-03-21T23:59:59.000Z
In this paper, quantum fluctuations of a carbonyl sulfide molecule in helium-4 clusters are studied as a function of cluster size N in a small-to-large size regime (2{<=}N{<=}64). The molecular rotation of the dopant shows nonmonotonic size dependence in the range of 10{<=}N{<=}20, reflecting the density distribution of the helium atoms around the molecule. The size dependence on the rotational constant shows a plateau for N{>=}20, which is larger than the experimental nanodroplet value. Superfluid response of the doped cluster is found to show remarkable anisotropy especially for N{<=}20. The superfluid fraction regarding the axis perpendicular to the molecular axis shows a steep increase at N=10, giving the significant enhancement of the rotational fluctuation of the molecule. On the other hand, the superfluid fraction regarding the axis parallel to the molecular axis reaches 0.9 at N=5, arising from the bosonic exchange cycles of the helium atoms around the molecular axis. The anisotropy in the superfluid response is found to be the direct consequence of the configurations of the bosonic exchange cycles.
Amro, Hanan, E-mail: hanan.amro@gmail.com [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Hamstra, Daniel A.; Mcshan, Daniel L. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Sandler, Howard [Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California (United States)] [Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California (United States); Vineberg, Karen; Hadley, Scott; Litzenberg, Dale [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)
2013-01-01T23:59:59.000Z
Purpose: To study the impact of daily rotations and translations of the prostate on dosimetric coverage during radiation therapy (RT). Methods and Materials: Real-time tracking data for 26 patients were obtained during RT. Intensity modulated radiation therapy plans meeting RTOG 0126 dosimetric criteria were created with 0-, 2-, 3-, and 5-mm planning target volume (PTV) margins. Daily translations and rotations were used to reconstruct prostate delivered dose from the planned dose. D{sub 95} and V{sub 79} were computed from the delivered dose to evaluate target coverage and the adequacy of PTV margins. Prostate equivalent rotation is a new metric introduced in this study to quantify prostate rotations by accounting for prostate shape and length of rotational lever arm. Results: Large variations in prostate delivered dose were seen among patients. Adequate target coverage was met in 39%, 65%, and 84% of the patients for plans with 2-, 3-, and 5-mm PTV margins, respectively. Although no correlations between prostate delivered dose and daily rotations were seen, the data showed a clear correlation with prostate equivalent rotation. Conclusions: Prostate rotations during RT could cause significant underdosing even if daily translations were managed. These rotations should be managed with rotational tolerances based on prostate equivalent rotations.
Stationary Axisymmetric and Slowly Rotating Spacetimes in Ho?ava-Lifshitz Gravity
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wang, Anzhong
2013-02-01T23:59:59.000Z
Stationary, axisymmetric, and slowly rotating vacuum spacetimes in the Horava-Lifshitz (HL) gravity are studied, and it is shown that, for any given spherical static vacuum solution of the HL theory (of any model, including the ones with an additional U(1) symmetry), there always exists a corresponding slowly rotating, stationary, and axisymmetric vacuum solution, which reduces to the former, when the rotation is switched off. The rotation is universal and only implicitly depends on the models of the HL theory and their coupling constants through the spherical seed solution. As a result, all asymptotically flat slowly rotating vacuum solutions are asymptotically identical to the slowly rotating Kerr solution. This is in contrast to the claim of Barausse and Sotiriou [Phys. Rev. Lett. 109, 181101 (2012)], in which slowly rotating black holes were reported (incorrectly) not to exist in the infrared limit of the nonprojectable HL theory.
Boyer, Edmond
509 E.-H. HALL. 2014 On the « rotational Coefficient in nickel and cobalt » ( Coefficients de rotation du nickel et du cobalt); Philosophical Magazine, 5e série, t. XII. p. 157; 1881. E.-H. HALL. 2014 pour le fer, le nickel, l'argent, l'or, le cobalt, l'aluminium, le magnésium; l'effet est bien moindre
Partial rotational lattice order–disorder in stefin B crystals
Renko, Miha [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, SI-1000 Ljubljana (Slovenia); Taler-Ver?i?, Ajda [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Miheli?, Marko [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, SI-1000 Ljubljana (Slovenia); Žerovnik, Eva [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Turk, Dušan, E-mail: dusan.turk@ijs.si [Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, SI-1000 Ljubljana (Slovenia)
2014-04-01T23:59:59.000Z
Crystal lattice disorders are a phenomenon which may hamper the determination of macromolecular crystal structures. Using the case of the crystal structure of stefin B, identification of rotational order–disorder and structure determination are described. At present, the determination of crystal structures from data that have been acquired from twinned crystals is routine; however, with the increasing number of crystal structures additional crystal lattice disorders are being discovered. Here, a previously undescribed partial rotational order–disorder that has been observed in crystals of stefin B is described. The diffraction images revealed normal diffraction patterns that result from a regular crystal lattice. The data could be processed in space groups I4 and I422, yet one crystal exhibited a notable rejection rate in the higher symmetry space group. An explanation for this behaviour was found once the crystal structures had been solved and refined and the electron-density maps had been inspected. The lattice of stefin B crystals is composed of five tetramer layers: four well ordered layers which are followed by an additional layer of alternatively placed tetramers. The presence of alternative positions was revealed by the inspection of electron-density score maps. The well ordered layers correspond to the crystal symmetry of space group I422. In addition, the positions of the molecules in the additional layer are related by twofold rotational axes which correspond to space group I422; however, these molecules lie on the twofold axis and can only be related in a statistical manner. When the occupancies of alternate positions and overlapping are equal, the crystal lattice indeed fulfills the criteria of space group I422; when these occupancies are not equal, the lattice only fulfills the criteria of space group I4.
Rotation, Statistical Dynamics and Kinematics of Globular Clusters
Donald Lynden-Bell
2000-07-10T23:59:59.000Z
Evolution with mass segregation and the evolution of the rotation of cores are both discussed for self-similar core collapse. Evolution with angular velocity proportional to the square root of the density is predicted. On the Dynamical Main Sequence of globular clusters the energy emission from binaries balances the energy expended in expanding the halo. Newton's exactly solved N-body problem is then given, along with recent generalisations, all of which have no violent relaxation, but a new type of statistical equilibrium is discussed. Finally, we set the creation of streams in the Galaxy's halo in the historical context of their discovery.
Loop quantization of the Gowdy model with local rotational symmetry
de Blas, Daniel Martín; Paw?owski, Tomasz
2015-01-01T23:59:59.000Z
We provide a full quantization of the vacuum Gowdy model with local rotational symmetry. We consider a redefinition of the constraints where the Hamiltonian Poisson-commutes with itself. We then apply of the canonical quantization program of loop quantum gravity within an improved dynamics scheme. We identify the exact solutions of the constraints and the physical observables, and we construct the physical Hilbert space. It is remarkable that quantum spacetimes are free of singularities. New quantum observables naturally arising in the treatment partially codify the discretization of the geometry. The preliminary analysis of the asymptotic future/past of the evolution indicates that the existing Abelianization technique needs further refinement.
Parity-odd effects and polarization rotation in graphene
I. V. Fialkovsky; D. V. Vassilevich
2009-02-15T23:59:59.000Z
We show that the presence of parity-odd terms in the conductivity (or, in other words, in the polarization tensor of Dirac quasiparticles in graphene) leads to rotation of polarization of the electromagnetic waves passing through suspended samples of graphene. Parity-odd Chern-Simons type contributions appear in external magnetic field, giving rise to a quantum Faraday effect (though other sources of parity-odd effects may also be discussed). The estimated order of the effect is well above the sensitivity limits of modern optical instruments.
Stator for a rotating electrical machine having multiple control windings
Shah, Manoj R. (Latham, NY); Lewandowski, Chad R. (Amsterdam, NY)
2001-07-17T23:59:59.000Z
A rotating electric machine is provided which includes multiple independent control windings for compensating for rotor imbalances and for levitating/centering the rotor. The multiple independent control windings are placed at different axial locations along the rotor to oppose forces created by imbalances at different axial locations along the rotor. The multiple control windings can also be used to levitate/center the rotor with a relatively small magnetic field per unit area since the rotor and/or the main power winding provides the bias field.
Control coil arrangement for a rotating machine rotor
Shah, Manoj R. (Latham, NY); Lewandowsk, Chad R. (Amsterdam, NY)
2001-07-31T23:59:59.000Z
A rotating machine (e.g., a turbine, motor or generator) is provided wherein a fixed solenoid or other coil configuration is disposed adjacent to one or both ends of the active portion of the machine rotor for producing an axially directed flux in the active portion so as to provide planar axial control at single or multiple locations for rotor balance, levitation, centering, torque and thrust action. Permanent magnets can be used to produce an axial bias magnetic field. The rotor can include magnetic disks disposed in opposed, facing relation to the coil configuration.
Gravitational collapse with rotating thin shells and cosmic censorship
Jorge V. Rocha
2015-03-17T23:59:59.000Z
Gravitational collapse of matter in the presence of rotation is a mostly unexplored topic but it might have important implications for cosmic censorship. Recently a convenient setup was identified to address this problem, by considering thin matter shells at the interface between two equal angular momenta Myers-Perry spacetimes in five dimensions. This note provides more details about the matching of such cohomogeneity-1 spacetimes and extends the results obtained therein to arbitrary higher odd dimensions. It is also pointed out that oscillatory orbits for shells in asymptotically flat spacetimes can be naturally obtained if the matter has a negative pressure component.
Solution of the Roth-Marques-Durian Rotational Abrasion Model
Bryan Gin-ge Chen
2010-12-10T23:59:59.000Z
We solve the rotational abrasion model of Roth, Marques and Durian (arXiv:1009.3492), a one-dimensional quasilinear partial differential equation resembling the inviscid Burgers equation with the unusual feature of a step function factor as a coefficient. The complexity of the solution is primarily in keeping track of the cases in the piecewise function that results from certain amputation and interpolation processes, so we also extract from it a model of an evolving planar tree graph that tracks the evolution of the coarse features of the contour.
Toroidal L and H equilibria with axisymmetric rotations
Tsui, K H
2009-01-01T23:59:59.000Z
Axisymmetric toroidal equilibria with toroidal and poloidal rotations are solved with a specific set of source functions. The two independent solutions are associated to L and H modes. The L/H transition is regarded as a bifurcation from one equilibrium configuration to another, under strong external heating and pellet injection to shape temperature and density profiles. Because of the steep edge gradient of the H solution, large static radial electric field, zonal flow, and improved confinements, come as consequences, not causes, of the H mode.
Carderock Rotating Arm Tow Tank | Open Energy Information
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Invariant-based pulse engineering without rotating wave approximation
S. Ibáñez; Yi-Chao Li; Xi Chen; J. G. Muga
2015-07-02T23:59:59.000Z
We inverse engineer realizable time-dependent semiclassical pulses to invert or manipulate a two- level system faster than adiabatically when the rotating-wave approximation cannot be applied. Different inversion routes, based on a counterdiabatic approach or invariants, lead quite generally to singular fields. Making use of the relation between the invariants of motion and the Hamiltonian, and canceling the troublesome singularities, an inversion scheme is put forward for the regime in which the pulse spans few oscillations. For many oscillations an alternative numerical minimization method is proposed and demonstrated.
Rotating cylindrical wormholes: a no-go theorem
K. A. Bronnikov
2015-09-23T23:59:59.000Z
The existing solutions to the Einstein equations describing rotating cylindrical wormholes are not asymptotically flat and therefore cannot describe wormhole entrances as local objects in our Universe. To overcome this difficulty, flat asymptotic regions are added to wormhole solutions by matching them at some surfaces $\\Sigma_-$ and $\\Sigma_+$. It is shown, however, that if the wormhole solution is obtained for scalar fields with arbitrary potentials, possibly interacting with an azimuthal electric or magnetic field, then the matter content of one or both thin shells appearing on $\\Sigma_-$ and $\\Sigma_+$ violate the Null Energy Condition. Thus exotic matter is still necessary for obtaining a twice asymptotically flat wormhole.
Nonlinear magneto-optic polarization rotation with intense laser fields
Hsu, Paul S.; Patnaik, Anil K.; Welch, George R.
2008-01-01T23:59:59.000Z
spectroscopy measurements #3;1,2#4;, both for fun- damental and practical reasons such as optical magnetometry #3;3#4;. The sensitivity of optical pumping magnetometers #1;OPMs#2; has already achieved 10?9 G /#5;Hz under laboratory conditions #3...;4,5#4;. Also, nonlinear magneto-optic rotation has been used in magnetometry to reach very high sensitivity #3;6#4;. In such devices, the Zeeman level shift measurements are based on light absorption #3;7#4;, but the sensitivity is limited if the absorption...
Control of Cotton Root Rot by Sweetclover in Rotation.
Hargrove, B.D.; Hill, H.O.; Dunlap, A.A.; Lyle, E. W. (Eldon W.)
1948-01-01T23:59:59.000Z
(the Temple area) are indica (Melilotus indica) and hubam (Melilotus nlbcr var. annun). Both were used in the rota- tion esperiments reported in this bulletin as winter and winter- summer crops. Rotation with hubam that is grown to maturity atsleast...-planted sweetclover showing desired amount of growth at time of plowing under for green manure in late winter or early spring. Figure 3. Fall-planted hubam showing height and dense stand at time of cutting for hay in early summer. BULLETIN 699, TEXAS AGRICULTURAL...
STRONG DEPENDENCE OF THE INNER EDGE OF THE HABITABLE ZONE ON PLANETARY ROTATION RATE
Yang, Jun; Abbot, Dorian S. [Department of Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States); Boué, Gwenaël; Fabrycky, Daniel C., E-mail: abbot@uchicago.edu [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)
2014-05-20T23:59:59.000Z
Planetary rotation rate is a key parameter in determining atmospheric circulation and hence the spatial pattern of clouds. Since clouds can exert a dominant control on planetary radiation balance, rotation rate could be critical for determining the mean planetary climate. Here we investigate this idea using a three-dimensional general circulation model with a sophisticated cloud scheme. We find that slowly rotating planets (like Venus) can maintain an Earth-like climate at nearly twice the stellar flux as rapidly rotating planets (like Earth). This suggests that many exoplanets previously believed to be too hot may actually be habitable, depending on their rotation rate. The explanation for this behavior is that slowly rotating planets have a weak Coriolis force and long daytime illumination, which promotes strong convergence and convection in the substellar region. This produces a large area of optically thick clouds, which greatly increases the planetary albedo. In contrast, on rapidly rotating planets a much narrower belt of clouds form in the deep tropics, leading to a relatively low albedo. A particularly striking example of the importance of rotation rate suggested by our simulations is that a planet with modern Earth's atmosphere, in Venus' orbit, and with modern Venus' (slow) rotation rate would be habitable. This would imply that if Venus went through a runaway greenhouse, it had a higher rotation rate at that time.
THE ROTATION PROFILE OF SOLAR MAGNETIC FIELDS BETWEEN {+-}60 Degree-Sign LATITUDES
Shi, X. J.; Xie, J. L., E-mail: shixiangjun@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)
2013-08-10T23:59:59.000Z
Through a cross-correlation analysis of the Carrington synoptic maps of solar photospheric magnetic fields from Carrington Rotation Nos. 1625 to 2129 (from 1975 February to 2012 October), the sidereal rotation rates of solar magnetic fields between {+-}60 Degree-Sign latitudes are investigated. It seems that the temporal variation of rotation rates should be related to the solar cycle phase. The rotation profile of magnetic fields is obtained: the sidereal rotation rates decrease from the equator to mid-latitude and reach their minimum values of about 13.16 deg day{sup -1} (13.17 deg day{sup -1}) at 53 Degree-Sign (54 Degree-Sign ) latitude in the northern (southern) hemisphere, then increase toward higher latitudes. This rotation profile is different from the differential rotation law obtained by Snodgrass from a cross-correlation analysis of daily magnetograms, in which the rotation rates show a steep decrease from the equator to the poles. However, it is much closer to the quasi-rigid rotation law derived by Stenflo from an auto-correlation analysis of daily magnetograms. Some possible interpretations are discussed for the resulting rotation profile.
Thermodynamics of rotating thin shells in the BTZ spacetime
Lemos, José P S; Minamitsuji, Masato; Rocha, Jorge V
2015-01-01T23:59:59.000Z
We investigate the thermodynamic equilibrium states of a rotating thin shell, i.e., a ring, in a (2+1)-dimensional spacetime with a negative cosmological constant. The inner and outer regions with respect to the shell are given by the vacuum anti-de Sitter (AdS) and the rotating Ba\\~{n}ados-Teitelbom-Zanelli (BTZ) spacetimes, respectively. The first law of thermodynamics on the thin shell, together with three equations of state for the pressure, the local inverse temperature and the thermodynamic angular velocity of the shell, yields the entropy of the shell, which is shown to depend only on its gravitational radii. When the shell is pushed to its own gravitational radius and its temperature is taken to be the Hawking temperature of the corresponding black hole, the entropy of the shell coincides with the Bekenstein-Hawking entropy. In addition, we consider simple ans\\"atze for the equations of state, as well as a power-law equation of state where the entropy and the thermodynamic stability conditions can be ...
Thermo-Rotational Instability in Plasma Disks Around Compact Objects
Bruno Coppi
2008-02-12T23:59:59.000Z
Differentially rotating plasma disks, around compact objects, that are imbedded in a ``seed'' magnetic field are shown to develop vertically localized ballooning modes that are driven by the combined radial gradient of the rotation frequency and vertical gradients of the plasma density and temperature. When the electron mean free path is shorter than the disk height and the relevant thermal conductivity can be neglected, the vertical particle flows produced by of these modes have the effect to drive the density and temperature profiles toward the ``adiabatic condition'' where $\\eta_{T}\\equiv(dlnT/dz)/(dlnn/dz)=2/3$. Here $T$ is the plasma temperature and $n$ the particle density. The faster growth rates correspond to steeper temperature profiles $(\\eta_{T}>2/3)$ such as those produced by an internal (e.g., viscous) heating process. In the end, ballooning modes excited for various values of $\\eta_{T}$ can lead to the evolution of the disk into a different current carrying configuration such as a sequence of plasma rings.
Physics of Intrinsic Rotation in Flux-Driven ITG Turbulence
Ku, S; Dimond, P H; Dif-Pradalier, G; Kwon, J M; Sarazin, Y; Hahm, T S; Garbet, X; Chang, C S; Latu, G; Yoon, E S; Ghendrih, Ph; Yi, S; Strugarek, A; Solomon, W
2012-02-23T23:59:59.000Z
Global, heat flux-driven ITG gyrokinetic simulations which manifest the formation of macroscopic, mean toroidal flow profiles with peak thermal Mach number 0.05, are reported. Both a particle-in-cell (XGC1p) and a semi-Lagrangian (GYSELA) approach are utilized without a priori assumptions of scale-separation between turbulence and mean fields. Flux-driven ITG simulations with different edge flow boundary conditions show in both approaches the development of net unidirectional intrinsic rotation in the co-current direction. Intrinsic torque is shown to scale approximately linearly with the inverse scale length of the ion temperature gradient. External momentum input is shown to effectively cancel the intrinsic rotation profile, thus confirming the existence of a local residual stress and intrinsic torque. Fluctuation intensity, intrinsic torque and mean flow are demonstrated to develop inwards from the boundary. The measured correlations between residual stress and two fluctuation spectrum symmetry breakers, namely E x B shear and intensity gradient, are similar. Avalanches of (positive) heat flux, which propagate either outwards or inwards, are correlated with avalanches of (negative) parallel momentum flux, so that outward transport of heat and inward transport of parallel momentum are correlated and mediated by avalanches. The probability distribution functions of the outward heat flux and the inward momentum flux show strong structural similarity
Chandrasekhar's relation and stellar rotation in the Kepler field
Silva, J. R. P.; Soares, B. B. [Grupo de Astroestatística, Departamento de Física, Universidade do Estado do Rio Grande do Norte, Mossoró-RN (Brazil); De Freitas, D. B., E-mail: joseronaldo@uern.br, E-mail: brauliosoares@uern.br, E-mail: danielbrito@dfte.ufrn.br [Departamento de Física, Universidade Federal do Rio Grande do Norte, Natal-RN (Brazil)
2014-11-20T23:59:59.000Z
According to the statistical law of large numbers, the expected mean of identically distributed random variables of a sample tends toward the actual mean as the sample increases. Under this law, it is possible to test the Chandrasekhar's relation (CR), (V) = (?/4){sup –1}(Vsin i), using a large amount of Vsin i and V data from different samples of similar stars. In this context, we conducted a statistical test to check the consistency of the CR in the Kepler field. In order to achieve this, we use three large samples of V obtained from Kepler rotation periods and a homogeneous control sample of Vsin i to overcome the scarcity of Vsin i data for stars in the Kepler field. We used the bootstrap-resampling method to estimate the mean rotations ((V) and (Vsin i)) and their corresponding confidence intervals for the stars segregated by effective temperature. Then, we compared the estimated means to check the consistency of CR, and analyzed the influence of the uncertainties in radii measurements, and possible selection effects. We found that the CR with (sin i) = ?/4 is consistent with the behavior of the (V) as a function of (Vsin i) for stars from the Kepler field as there is a very good agreement between such a relation and the data.
The rotating wind of the quasar PG 1700+518
S. Young; D. J. Axon; A. Robinson; J. H. Hough; J. E. Smith
2008-02-27T23:59:59.000Z
It is now widely accepted that most galaxies undergo an active phase, during which a central super-massive black hole generates vast radiant luminosities through the gravitational accretion of gas. Winds launched from a rotating accretion disk surrounding the black hole are thought to play a critical role, allowing the disk to shed angular momentum that would otherwise inhibit accretion. Such winds are capable of depositing large amounts of mechanical energy in the host galaxy and its environs, profoundly affecting its formation and evolution, and perhaps regulating the formation of large-scale cosmological structures in the early Universe. Although there are good theoretical grounds for believing that outflows from active galactic nuclei originate as disk winds, observational verification has proven elusive. Here we show that structures observed in polarized light across the broad H-alpha emission line in the quasar PG 1700+158 originate close to the accretion disk in an electron scattering wind. The wind has large rotational motions (~4,000 km/s), providing direct observational evidence that outflows from active galactic nuclei are launched from the disks. Moreover, the wind rises nearly vertically from the disk, favouring launch mechanisms that impart an initial acceleration perpendicular to the disk plane.
Bulk emission of scalars by a rotating black hole
M. Casals; S. R. Dolan; P. Kanti; E. Winstanley
2008-07-17T23:59:59.000Z
We study in detail the scalar-field Hawking radiation emitted into the bulk by a higher-dimensional, rotating black hole. We numerically compute the angular eigenvalues, and solve the radial equation of motion in order to find transmission factors. The latter are found to be enhanced by the angular momentum of the black hole, and to exhibit the well-known effect of superradiance. The corresponding power spectra for scalar fields show an enhancement with the number of dimensions, as in the non-rotating case. We compute the total mass loss rate of the black hole for a variety of black-hole angular momenta and bulk dimensions, and find that, in all cases, the bulk emission remains significantly smaller than the brane emission. The angular-momentum loss rate is also computed and found to have a smaller value in the bulk than on the brane. We present accurate bulk-to-brane emission ratios for a range of scenarios.
On the Nuclear Rotation Curve of M31
Thomas S. Statler
1999-05-08T23:59:59.000Z
The nuclear rotation curve of M31, as observed by the Hubble Space Telescope Faint Object Camera Spectrograph, shows a significant disturbance coinciding with the off-center brightness peak, P1. This +/- 60 km/s feature is distinguished by a local velocity maximum centered on P1 and a local minimum approxmately 0.08" closer to P2. If the M31 double nucleus is an eccentric disk with an off-center density concentration, as suggested by Tremaine, then the self-gravity of the disk can produce just such a disturbance. The expected kinematic signature is calculated approximately by examining sequences of closed periodic orbits in a Kepler potential perturbed by a model disk potential that precesses at constant frequency. The perturbation forces a steep negative eccentricity gradient in the sequence of closed orbits through the densest part of the disk, which reverses the arrangement of periapsis and apoapsis with respect to the central mass. Stars making up the inner part of the density concentration are at apoapsis, while stars making up the outer part are at periapsis, producing a steep local velocity gradient. This result is independent of the details of the mass distribution. The projected rotation curve of the model is shown to closely resemble that of M31, giving strong support to the eccentric disk picture.
Measurement of Gravitomagnetic and Acceleration Fields Around Rotating Superconductors
M. Tajmar; F. Plesescu; B. Seifert; K. Marhold
2006-10-17T23:59:59.000Z
It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so-called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper-pairs. A similar field is predicted from Einstein's general relativity theory and the presently observed amount of dark energy in the universe. An experimental facility was designed and built to measure small acceleration fields as well as gravitomagnetic fields in the vicinity of a fast rotating and accelerating superconductor in order to detect this so-called gravitomagnetic London moment. This paper summarizes the efforts and results that have been obtained so far. Measurements with Niobium superconductors indeed show first signs which appear to be within a factor of 2 of our theoretical prediction. Possible error sources as well as the experimental difficulties are reviewed and discussed. If the gravitomagnetic London moment indeed exists, acceleration fields could be produced in a laboratory environment.
Miura, Shinichi [Institute for Molecular Science, 38 Myodaiji, Okazaki 444-8585 (Japan)
2007-03-21T23:59:59.000Z
In this paper, we present a path integral hybrid Monte Carlo (PIHMC) method for rotating molecules in quantum fluids. This is an extension of our PIHMC for correlated Bose fluids [S. Miura and J. Tanaka, J. Chem. Phys. 120, 2160 (2004)] to handle the molecular rotation quantum mechanically. A novel technique referred to be an effective potential of quantum rotation is introduced to incorporate the rotational degree of freedom in the path integral molecular dynamics or hybrid Monte Carlo algorithm. For a permutation move to satisfy Bose statistics, we devise a multilevel Metropolis method combined with a configurational-bias technique for efficiently sampling the permutation and the associated atomic coordinates. Then, we have applied the PIHMC to a helium-4 cluster doped with a carbonyl sulfide molecule. The effects of the quantum rotation on the solvation structure and energetics were examined. Translational and rotational fluctuations of the dopant in the superfluid cluster were also analyzed.
Bai,M.; Ptitsyn, V.; Roser, T.
2008-10-01T23:59:59.000Z
To keep the spin tune in the spin depolarizing resonance free region is required for accelerating polarized protons to high energy. In RHIC, two snakes are located at the opposite side of each accelerator. They are configured to yield a spin tune of 1/2. Two pairs of spin rotators are located at either side of two detectors in each ring in RHIC to provide longitudinal polarization for the experiments. Since the spin rotation from vertical to longitudinal is localized between the two rotators, the spin rotators do not change the spin tune. However, due to the imperfection of the orbits around the snakes and rotators, the spin tune can be shifted. This note presents the impact of the horizontal orbital angle between the two snakes on the spin tune, as well as the effect of the vertical orbital angle between two rotators at either side of the collision point on the spin tune.
Slowly rotating superfluid neutron stars with isospin dependent entrainment in a two-fluid model
Kheto, Apurba
2015-01-01T23:59:59.000Z
We investigate the slowly rotating general relativistic superfluid neutron stars including the entrainment effect in a two-fluid model, where one fluid represents the superfluid neutrons and the other is the charge-neutral fluid called the proton fluid, made of protons and electrons. The equation of state and the entrainment effect between the superfluid neutrons and the proton fluid are computed using a relativistic mean field (RMF) model where baryon-baryon interaction is mediated by the exchange of $\\sigma$, $\\omega$, and $\\rho$ mesons and scalar self interactions are also included. The equations governing rotating neutron stars in the slow rotation approximation are second order in rotational velocities of neutron and proton fluids. We explore the effects of the isospin dependent entrainment and the relative rotation between two fluids on the global properties of rotating superfluid neutron stars such as mass, shape, and the mass shedding (Kepler) limit within the RMF model with different parameter sets. ...
Berry's phase for a noncyclic rotation of light in a helically wound optical fiber
Morinaga, Atsuo; Monma, Akinori; Honda, Kazuhito; Kitano, Masao [Department of Physics, Faculty of Science and Technology, 2641 Yamazaki, Noda-shi, Chiba 278-8510 (Japan); Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyou-ku, Kyoto 615-8510 (Japan)
2007-11-15T23:59:59.000Z
We investigated Berry's phase for noncyclic evolution using the rotation of a polarization azimuth of linearly polarized light in a partially wound optical fiber over the surface of a cylinder. Using a rotation gauge around the rotation axis, the observed rotation of the polarization azimuth corresponds to the area of a spherical rectangle over the surface enclosed by the contour C of actual evolution, a large circle on the equator, and a longitudinal line connecting them, whereas the rotation of the polar gauge encloses a spherical triangle connecting the zenith of the sphere. The observed values were converted to Berry's phase by transformation from the rotation gauge to the geodesic gauge. Consequently, we could confirm that Berry's phase for a noncyclic evolution is given by the geodesic rule proposed by Samuel and Bhandari.
Unstable domains of tearing and Kelvin-Helmholtz instabilities in a rotating cylindrical plasma
Fan, D. M.; Wei, L.; Wang, Z. X., E-mail: zxwang@dlut.edu.cn; Zheng, S. [Key Laboratory of Materials Modification by Beams of the Ministry of Education, School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024 (China); Duan, P. [Department of Physics, Dalian Maritime University, Dalian 116026 (China)
2014-09-15T23:59:59.000Z
Effects of poloidal rotation profile on tearing and Kelvin-Helmholtz (KH) instabilities in a cylindrical plasma are investigated by using a reduced magnetohydrodynamic model. Since the poloidal rotation has different effects on the tearing and KH modes in different rotation regimes, four unstable domains are numerically identified, i.e., the destabilized tearing mode domain, stabilized tearing mode domain, stable-window domain, and unstable KH mode domain. It is also found that when the rotation layer is in the outer region of the rational surface, the stabilizing role of the rotation can be enhanced so significantly that the stable window domain is enlarged. Moreover, Alfvén resonances can be induced by the tearing and KH modes in such rotating plasmas. Radially wide profiles of current and vorticity perturbations can be formed when multiple current sheets on different resonance positions are coupled together.
Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China); Wei, Yuquan, E-mail: yuquawei@vip.sina.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China)
2013-07-01T23:59:59.000Z
The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.
Modification of the Doppler Effect due to the Helicity-Rotation Coupling
Bahram Mashhoon
2002-10-20T23:59:59.000Z
The helicity-rotation coupling and its current empirical basis are examined. The modification of the Doppler effect due to the coupling of photon spin with the rotation of the observer is considered in detail in connection with its applications in the Doppler tracking of spacecraft. Further implications of this coupling and the possibility of searching for it in the intensity response of a rotating detector are briefly discussed.
M. A. Caprio; P. Maris; J. P. Vary
2013-01-06T23:59:59.000Z
The emergence of rotational bands is observed in no-core configuration interaction (NCCI) calculations for the odd-mass Be isotopes (7<=A<=13) with the JISP16 nucleon-nucleon interaction, as evidenced by rotational patterns for excitation energies, quadrupole moments, and E2 transitions. Yrast and low-lying excited bands are found. The results demonstrate the possibility of well-developed rotational structure in NCCI calculations using a realistic nucleon-nucleon interaction.
Rotating charged hairy black hole in (2+1) dimensions and particle acceleration
J. Sadeghi; B. Pourhassan; H. Farahani
2013-10-26T23:59:59.000Z
In this paper we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.
Simulation of Alpha Particles in Rotating Plasma Interacting with a Stationary Ripple
Abraham J. Fetterman and Nathaniel J. Fisch
2011-01-11T23:59:59.000Z
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.
Teodorescu, C.; Young, W. C.; Swan, G. W. S.; Ellis, R. F.; Hassam, A. B.; Romero-Talamas, C. A. [University of Maryland, College Park, Maryland 20742 (United States)
2010-08-20T23:59:59.000Z
Interferometric density measurements in plasmas rotating in shaped, open magnetic fields demonstrate strong confinement of plasma parallel to the magnetic field, with density drops of more than a factor of 10. Taken together with spectroscopic measurements of supersonic ExB rotation of sonic Mach 2, these measurements are in agreement with ideal MHD theory which predicts large parallel pressure drops balanced by centrifugal forces in supersonically rotating plasmas.
Modeling Poplar Growth as a Short Rotation Woody Crop for Biofuels
Hart, Quinn James
2014-01-01T23:59:59.000Z
a Short Rotation Woody Crop for Biofuels Q. J. Hart 1,? , O.for cellulosic derived biofuels. The ability to accuratelycrops for bioenergy and biofuels applications. In vitro
Webinar: Testing Oxygen Reduction Reaction Activity with the Rotating Disc Electrode Technique
Broader source: Energy.gov [DOE]
Video recording of the Fuel Cell Technologies Office webinar, Testing Oxygen Reduction Reaction Activity with the Rotating Disc Electrode Technique, originally presented on March 12, 2013.
Robinson, Luke Thomas
2013-01-01T23:59:59.000Z
detection for structural health monitoring using Holderplacement for structural health monitoring with applicationRotating Machinery, Structural Health Monitoring, Shock and
Primary, secondary instabilities and control of the rotating-disk boundary layer
;Typical 3D boundary layers rotating disk swept wing Common features: · crossflow component near the wall · inflection point · strong inviscid instability · secondary instabilities ; growth and saturation of crossflow
Xing M. Wang
2009-01-30T23:59:59.000Z
In this article, we continue to investigate the application of Probability Bracket Notation (PBN). We show that, under Special Wick Rotation (caused by imaginary-time rotation), the Schrodinger equation of a conservative system and its path integral in Dirac rotation are simultaneously shifted to the master equation and its Euclidean path integral of an induced micro diffusion in PBN. Moreover, by extending to General Wick Rotation and using the anti-Hermitian wave-number operator, we execute the path integral in Dirac notation side-by-side with the Euclidean path integral in PBN, and derive the Euclidean Lagrangian of induced diffusions and Smoluchowski equation.
ARM - Publications: Science Team Meeting Documents
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirtA JourneygovCampaignsPajaritogovField CampaignsMidlatitudeAprilAnalysis of Rotating Shadowband
Rotating Hayward's regular black hole as particle accelerator
Muhammed Amir; Sushant G. Ghosh
2015-06-10T23:59:59.000Z
Recently, Ban\\~{a}dos, Silk and West (BSW) demonstrated that the extremal Kerr black hole can act as a particle accelerator with arbitrarily high center-of-mass energy ($E_{CM}$) when the collision takes place near the horizon. The rotating Hayward's regular black hole, apart from Mass ($M$) and angular momentum ($a$), has a new parameter $g$ ($g>0$ is a constant) that provides a deviation from the Kerr black hole. We demonstrate that for each $g$, with $M=1$, there exist critical $a_{E}$ and $r_{H}^{E}$, which corresponds to a regular extremal black hole with degenerate horizon, and $a_{E}$ decreases and $r_{H}^{E}$ increases with increase in $g$. While $aparticle accelerator and thus in turn may provide a suitable framework for Plank-scale physics. For a non-extremal case, there always exist a finite upper bound of $E_{CM}$, which increases with deviation parameter $g$.
Double rotation NMR studies of zeolites and aluminophosphate molecular sieves
Jelinek, R. [California Univ., Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States)
1993-07-01T23:59:59.000Z
Goal is to study the organization and structures of guest atoms and molecules and their reactions on internal surfaces within pores of zeolites and aluminophosphate molecular sieves. {sup 27}Al and {sup 23}Na double rotation NMR (DOR) is used since it removes the anisotropic broadening in NMR spectra of quadrupolar nuclei, thus increasing resolution. This work concentrates on probing aluminum framework atoms in aluminophosphate molecular sieves and sodium extra framework cations in porous aluminosilicates. In aluminophosphates, ordering and electronic environments of the framework {sup 27}Al nuclei are modified upon adsorption of water molecules within the channels; a relation is sought between the sieve channel topology and the organization of adsorbed water, as well as the interaction between the Al nuclei and the water molecules. Extra framework Na{sup +} cations are directly involved in adsorption processes and reactions in zeolite cavities.
Rotation Rate of Particle Pairs in Homogeneous Isotropic Turbulence
Daddi-Moussa-Ider, Abdallah
2015-01-01T23:59:59.000Z
Understanding the dynamics of particles in turbulent flow is important in many environmental and industrial applications. In this paper, the statistics of particle pair orientation is numerically studied in homogeneous isotropic turbulent flow, with Taylor microscale Rynolds number of 300. It is shown that the Kolmogorov scaling fails to predict the observed probability density functions (PDFs) of the pair rotation rate and the higher order moments accurately. Therefore, a multifractal formalism is derived in order to include the intermittent behavior that is neglected in the Kolmogorov picture. The PDFs of finding the pairs at a given angular velocity for small relative separations, reveals extreme events with stretched tails and high kurtosis values. Additionally, The PDFs are found to be less intermittent and follow a complementary error function distribution for larger separations.
Periodic relativity: deflection of light, acceleration, rotation curves
Vikram H. Zaveri
2014-12-08T23:59:59.000Z
Vectorial analysis relating to derivation of deflection of light is presented. Curvilinear acceleration is distinguished from the Newtonian polar conic acceleration. The difference between the two is due to the curvature term. Lorentz invariant expression for acceleration is derived. A physical theory of rotation curves of galaxies based on second solution to Einstein's field equation is presented. Theory is applied to Milky Way, M31, NGC3198 and Solar system. Modified Kepler's third law yields correct orbital periods of stars in a galaxy. Deviation factor in the line element of the theory happens to be the ratio of the Newtonian gravitational acceleration to the measured acceleration of the star in the galaxy. Therefore this deviation factor can replace the MOND function.
Test of the Equivalence Principle Using a Rotating Torsion Balance
S. Schlamminger; K. -Y. Choi; T. A. Wagner; J. H. Gundlach; E. G. Adelberger
2007-12-04T23:59:59.000Z
We used a continuously rotating torsion balance instrument to measure the acceleration difference of beryllium and titanium test bodies towards sources at a variety of distances. Our result Delta a=(0.6+/-3.1)x10^-15 m/s^2 improves limits on equivalence-principle violations with ranges from 1 m to infinity by an order of magnitude. The Eoetvoes parameter is eta=(0.3+/-1.8)x10^-13. By analyzing our data for accelerations towards the center of the Milky Way we find equal attractions of Be and Ti towards galactic dark matter, yielding eta=(-4 +/- 7)x10^-5. Space-fixed differential accelerations in any direction are limited to less than 8.8x10^-15 m/s^2 with 95% confidence.
Exact Rotating Magnetic Traversable Wormholes satisfying the Energy Conditions
Tonatiuh Matos; Galaxia Miranda
2015-07-09T23:59:59.000Z
In this work we wonder if there is a way to generate a wormhole (WH) in nature using "normal" matter. In order to give a first answer to this question, we study a massless scalar field coupled to an electromagnetic one (dilatonic field) with an arbitrary coupling constant, as source of gravitation. We obtain an exact solution of the Einstein equations using this source that represents a magnetized rotating WH. This space-time has a naked ring singularity, probably untouchable as in \\cite{Matos:2012gj}, but otherwise regular. The WH throat lies on the disc bounded by the ring singularity, which keeps the throat open without requiring exotic matter, that means, satisfying all the energy conditions. After analyzing the geodesic motion and the tidal forces we find that a test particle can go through the WH without troubles.
Exact Rotating Magnetic Traversable Wormholes satisfying the Energy Conditions
Matos, Tonatiuh
2015-01-01T23:59:59.000Z
In this work we wonder if there is a way to generate a wormhole (WH) in nature using "normal" matter. In order to give a first answer to this question, we study a massless scalar field coupled to an electromagnetic one (dilatonic field) with an arbitrary coupling constant, as source of gravitation. We obtain an exact solution of the Einstein equations using this source that represents a magnetized rotating WH. This space-time has a naked ring singularity, probably untouchable as in \\cite{Matos:2012gj}, but otherwise regular. The WH throat lies on the disc bounded by the ring singularity, which keeps the throat open without requiring exotic matter, that means, satisfying all the energy conditions. After analyzing the geodesic motion and the tidal forces we find that a test particle can go through the WH without troubles.
Dark matter transport properties and rapidly rotating neutron stars
C. J. Horowitz
2012-05-16T23:59:59.000Z
Neutron stars are attractive places to look for dark matter because their high densities allow repeated interactions. Weakly interacting massive particles (WIMPs) may scatter efficiently in the core or in the crust of a neutron star. In this paper we focus on WIMP contributions to transport properties, such as shear viscosity or thermal conductivity, because these can be greatly enhanced by long mean free paths. We speculate that WIMPs increase the shear viscosity of neutron star matter and help stabilize r-mode oscillations. These are collective oscillations where the restoring force is the Coriolis force. At present r-modes are thought to be unstable in many observed rapidly rotating stars. If WIMPs stabilize the r-modes, this would allow neutron stars to spin rapidly. This likely requires WIMP-nucleon cross sections near present experimental limits and an appropriate density of WIMPs in neutron stars.
Nanoparticles at liquid interfaces: Rotational dynamics and angular locking
Razavi, Sepideh; Kretzschmar, Ilona [Department of Chemical Engineering, City College of City University of New York, New York, New York 10031 (United States)] [Department of Chemical Engineering, City College of City University of New York, New York, New York 10031 (United States); Koplik, Joel [Department of Physics and The Benjamin Levich Institute for Physico-chemical Hydrodynamics, City College of City University of New York, New York, New York 10031 (United States)] [Department of Physics and The Benjamin Levich Institute for Physico-chemical Hydrodynamics, City College of City University of New York, New York, New York 10031 (United States); Colosqui, Carlos E., E-mail: carlos.colosqui@stonybrook.edu [Department of Mechanical Engineering, Stony Brook University, Stony Brook, New York 11794 (United States)
2014-01-07T23:59:59.000Z
Nanoparticles with different surface morphologies that straddle the interface between two immiscible liquids are studied via molecular dynamics simulations. The methodology employed allows us to compute the interfacial free energy at different angular orientations of the nanoparticle. Due to their atomistic nature, the studied nanoparticles present both microscale and macroscale geometrical features and cannot be accurately modeled as a perfectly smooth body (e.g., spheres and cylinders). Under certain physical conditions, microscale features can produce free energy barriers that are much larger than the thermal energy of the surrounding media. The presence of these energy barriers can effectively “lock” the particle at specific angular orientations with respect to the liquid-liquid interface. This work provides new insights on the rotational dynamics of Brownian particles at liquid interfaces and suggests possible strategies to exploit the effects of microscale features with given geometric characteristics.
Arbitrary Rotation Invariant Random Matrix Ensembles and Supersymmetry
Thomas Guhr
2006-06-03T23:59:59.000Z
We generalize the supersymmetry method in Random Matrix Theory to arbitrary rotation invariant ensembles. Our exact approach further extends a previous contribution in which we constructed a supersymmetric representation for the class of norm-dependent Random Matrix Ensembles. Here, we derive a supersymmetric formulation under very general circumstances. A projector is identified that provides the mapping of the probability density from ordinary to superspace. Furthermore, it is demonstrated that setting up the theory in Fourier superspace has considerable advantages. General and exact expressions for the correlation functions are given. We also show how the use of hyperbolic symmetry can be circumvented in the present context in which the non-linear sigma model is not used. We construct exact supersymmetric integral representations of the correlation functions for arbitrary positions of the imaginary increments in the Green functions.
Innovative Sensors for Pipeline Crawlers: Rotating Permanent Magnet Inspection
J. Bruce Nestleroth; Richard J. Davis; Stephanie Flamberg
2006-09-30T23:59:59.000Z
Internal inspection of pipelines is an important tool for ensuring safe and reliable delivery of fossil energy products. Current inspection systems that are propelled through the pipeline by the product flow cannot be used to inspect all pipelines because of the various physical barriers they may encounter. To facilitate inspection of these ''unpiggable'' pipelines, recent inspection development efforts have focused on a new generation of powered inspection platforms that are able to crawl slowly inside a pipeline and can maneuver past the physical barriers that limit internal inspection applicability, such as bore restrictions, low product flow rate, and low pressure. The first step in this research was to review existing inspection technologies for applicability and compatibility with crawler systems. Most existing inspection technologies, including magnetic flux leakage and ultrasonic methods, had significant implementation limitations including mass, physical size, inspection energy coupling requirements and technology maturity. The remote field technique was the most promising but power consumption was high and anomaly signals were low requiring sensitive detectors and electronics. After reviewing each inspection technology, it was decided to investigate the potential for a new inspection method. The new inspection method takes advantage of advances in permanent magnet strength, along with their wide availability and low cost. Called rotating permanent magnet inspection (RPMI), this patent pending technology employs pairs of permanent magnets rotating around the central axis of a cylinder to induce high current densities in the material under inspection. Anomalies and wall thickness variations are detected with an array of sensors that measure local changes in the magnetic field produced by the induced current flowing in the material. This inspection method is an alternative to the common concentric coil remote field technique that induces low-frequency eddy currents in ferromagnetic pipes and tubes. Since this is a new inspection method, both theory and experiment were used to determine fundamental capabilities and limitations. Fundamental finite element modeling analysis and experimental investigations performed during this development have led to the derivation of a first order analytical equation for designing rotating magnetizers to induce current and positioning sensors to record signals from anomalies. Experimental results confirm the analytical equation and the finite element calculations provide a firm basis for the design of RPMI systems. Experimental results have shown that metal loss anomalies and wall thickness variations can be detected with an array of sensors that measure local changes in the magnetic field produced by the induced current flowing in the material. The design exploits the phenomenon that circumferential currents are easily detectable at distances well away from the magnets. Current changes at anomalies were detectable with commercial low cost Hall Effect sensors. Commercial analog to digital converters can be used to measure the sensor output and data analysis can be performed in real time using PC computer systems. The technology was successfully demonstrated during two blind benchmark tests where numerous metal loss defects were detected. For this inspection technology, the detection threshold is a function of wall thickness and corrosion depth. For thinner materials, the detection threshold was experimentally shown to be comparable to magnetic flux leakage. For wall thicknesses greater than three tenths of an inch, the detection threshold increases with wall thickness. The potential for metal loss anomaly sizing was demonstrated in the second benchmarking study, again with accuracy comparable to existing magnetic flux leakage technologies. The rotating permanent magnet system has the potential for inspecting unpiggable pipelines since the magnetizer configurations can be sufficiently small with respect to the bore of the pipe to pass obstructions that limit the application of many i
On the Rotational and Machian Properties of the Universe
Marcelo Samuel Berman
2008-07-11T23:59:59.000Z
We find a Classical explanation on the origin of the Cosmological "constant" term, as a rotating feature of the Universe. We give a picture on "creation" of the Universe. By analogy with the original Brans-Dicke relation, several other similar relations were obtained in a previous paper (Berman, 2007d), which we now extend, by relating the angular momentum L, absolute temperature T, and the cosmological "constant", with R, where R, M stand for the radius (scale-factor) and the mass of the causally related Universe. We show here that these properties, which characterize Machian Universes, can be put in the form of equalities, which can be derived, from the conjecture that the total energy of the Universe is null, alike with the effective energy density, and we therefore imply that R depends linearly with M ; the angular momentum runs like squared R ; T, like R to the power -1/2 ; lambda, as R to the power -2 so that the total entropy of the Universe grows with R to the power 3/2, and, then, also as M to the power 3/2. The "loss of information paradox", for black holes, is dismantled. It must be obvious, from this paper, that each type of energy contribution, to the total energy of the Universe, divided by M multiplied by c-squared, yields a constant, during all times, so that, for instance, if the present contribution of the cosmological "constant", drives the present Universe, it also must have driven alike, in all the lifespan of the Machian Universe: the relative contributions of densities of each kind, towards the total density, remain the same during all times. Berman (2008; 2008a; 2008b) found similar hidden rotational states of the Universe in Relativistic theories which obey Robertson-Walker's metric.
Rotational energy analysis for rotatingvibrating linear molecules in classical trajectory simulation
Kim, Myung Soo
investigation,26 the mode-specific analy- sis of product energy in classical trajectory simulation, the aboveRotational energy analysis for rotatingvibrating linear molecules in classical trajectory simulation Sang Tae Park, Jeong Hee Moon, and Myung Soo Kima) Department of Chemistry and Center
Single-ended counter-rotating radial turbine for space application
Coomes, E.P.; Wilson, D.G.; Webb, B.J.; McCabe, S.J.
1987-05-13T23:59:59.000Z
A single-ended turbine with counter-rotating blades operating with sodium as the working fluid. The single-ended, counter-rotating feature of the turbine results in zero torque application to a space platform. Thus, maneuvering of the platform is not adversely affected by the turbine. 4 figs.
of the cut-off frequency. The rotational propulsion characteristics of helical swimmers with a magnetic headThe Rotational Propulsion Characteristics of Scaled-up Helical Microswimmers with different heads and magnetic positioning Tiantian Xu1, Gilgueng Hwang2, Nicolas Andreff3 and St´ephane R´egnier1 Abstract
Hu, Hui
of Turbine Rotation Directions on the Wake Interference of Wind Turbines Wei Yuan1 , Ahmet Ozbay2 , Wei Tian3 to investigate on the effects of the relative rotation directions of two tandwm wind turbines on the power production performance and flow characteristics in the wakes of two wind turbines in tandem. The experimental
Wesfreid, José Eduardo
Gap size effects on centrifugally and rotationally driven instabilities innocent Mutabaz 1991) The rotation effects on centrifugally driven instabilities in curved channel flow with a finite these instabilities are due to the curvature of streamlines in- ducing a centrifugal force which unbalances the radial
A Fourier-spectral element algorithm for thermal convection in rotating axisymmetric containers
Fournier, Alexandre
A Fourier-spectral element algorithm for thermal convection in rotating axisymmetric containers Abstract We present a Fourier-spectral element approach for modeling thermal convection in a rotating, Spectral Methods for Axisymmetric Domains, Gauthier-Villars, Paris, 1999], a Fourier expansion of the field
Jet impingement heat transfer in two-pass rotating rectangular channels
Zhang, Yuming
1996-01-01T23:59:59.000Z
of multiple, staggered array, round impinging air jets are presented. The jet rotation number (Ro) is varied from 0.0 to 0.0226, and the jet Reynolds number (Rej) is varied from 2,500 to 12,500. The isolated effects of Rej, and rotating speed (D = 0, 400...
Rotational stabilization of pinch instabilities in Taylor-Couette flow Dima Shalybkov*
Rotational stabilization of pinch instabilities in Taylor-Couette flow Dima Shalybkov* A.F. Ioffe Institute for Physics and Technology, 194021, St. Petersburg, Russia Received 25 October 2006; published 11-known pinch type instability. The stable rotation stabilizes the unstable azimuthal magnetic field
Faraday rotation enhancement of gold coated Fe2O3 nanoparticles: comparison of experiment and theory
Wysin, Gary
Faraday rotation enhancement of gold coated Fe2O3 nanoparticles: comparison of experiment to evaluate their potential for application. In this study, the Faraday rotation enhancement of gold coated Fe2O3 nanoparticles (NP) is investigated experimentally and theoretically. The experiment shows
Rotation Angle for the Optimum Tracking of One-Axis Trackers
Marion, W. F.; Dobos, A. P.
2013-07-01T23:59:59.000Z
An equation for the rotation angle for optimum tracking of one-axis trackers is derived along with equations giving the relationships between the rotation angle and the surface tilt and azimuth angles. These equations are useful for improved modeling of the solar radiation available to a collector with tracking constraints and for determining the appropriate motor revolutions for optimum tracking.
A Study of the Jacobi Shape Transition in Light, Fast Rotating Nuclei with the EUROBALL IV,
Pomorski, Krzysztof
A Study of the Jacobi Shape Transition in Light, Fast Rotating Nuclei with the EUROBALL IV, HECTOR the predicted Jacobi shape transition in light nuclei. A comparison of the GDR line shape data calculations, shows evidence for such Jacobi shape transition in hot, rapidly rotating 46 Ti. The found narrow
Vibrational-Rotational Energy Distributions in the Reaction O-+ D2 f OD + D-
Farrar, James M.
Vibrational-Rotational Energy Distributions in the Reaction O- + D2 f OD + D- Yue Li, Li Liu with a bimodal rotational energy distribution. At the higher collision energy, both V ) 0 and 1 products energy range up to 10 eV. By measuring the kinetic energy distribution of the detached electrons
Multipole-multimode Floquet theory of rotational resonance width experiments: 13
Griffin, Robert G.
Multipole-multimode Floquet theory of rotational resonance width experiments: 13 C13 C distance description of zero-quantum ZQ NMR processes using multipole-multimode Floquet theory is proposed for studying in rotational resonance width R2 W ex- periments based on multipole-multimode Floquet theory MMFT . The approach
Chjan C. Lim
2006-08-09T23:59:59.000Z
A new variational principle - extremizing the fixed frame kinetic energy under constant relative enstrophy - for a coupled barotropic flow - rotating solid sphere system is introduced with the following consequences. In particular, angular momentum is transfered between the fluid and the solid sphere through a modelled torque mechanism. The fluid's angular momentum is therefore not fixed but only bounded by the relative enstrophy, as is required of any model that supports super-rotation. The main results are: At any rate of spin $\\Omega $ and relative enstrophy, the unique global energy maximizer for fixed relative enstrophy corresponds to solid-body super-rotation; the counter-rotating solid-body flow state is a constrained energy minimum provided the relative enstrophy is small enough, otherwise, it is a saddle point. For all energy below a threshold value which depends on the relative enstrophy and solid spin $\\Omega $, the constrained energy extremals consist of only minimizers and saddles in the form of counter-rotating states$.$ Only when the energy exceeds this threshold value can pro-rotating states arise as global maximizers. Unlike the standard barotropic vorticity model which conserves angular momentum of the fluid, the counter-rotating state is rigorously shown to be nonlinearly stable only when it is a local constrained minima. The global constrained maximizer corresponding to super-rotation is always nonlinearly stable.
Continuous-wave high-power rotational Raman generation in molecular deuterium
Yavuz, Deniz
Continuous-wave high-power rotational Raman generation in molecular deuterium J. T. Green, D. E the generation of more than 300 mW of rotational Stokes output power in a CW Raman laser. The generation and the generated wavelengths. Advances in high-reflectivity, ultralow loss dielectric coatings have allowed CW
The effect of diamagnetic flows on turbulent driven ion toroidal rotation
Lee, J. P. [Courant Institute of Mathematical Sciences, New York University, New York, New York 10003 (United States)] [Courant Institute of Mathematical Sciences, New York University, New York, New York 10003 (United States); Barnes, M. [Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States)] [Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States); Parra, F. I. [Rudolf Peierls Centre for Theoretical Physics, Oxford University, Oxford OX1 3NP (United Kingdom)] [Rudolf Peierls Centre for Theoretical Physics, Oxford University, Oxford OX1 3NP (United Kingdom); Belli, E. A.; Candy, J. [General Atomics, San Diego, California 92121 (United States)] [General Atomics, San Diego, California 92121 (United States)
2014-05-15T23:59:59.000Z
Turbulent momentum redistribution determines the radial profile of rotation in a tokamak. The momentum transport driven by diamagnetic flow effects is an important piece of the radial momentum transport for sub-sonic rotation, which is often observed in experiments. In a non-rotating state, the diamagnetic flow and the E × B flow must cancel. The diamagnetic flow and the E × B flow have different effects on the turbulent momentum flux, and this difference in behavior induces intrinsic rotation. The momentum flux is evaluated using gyrokinetic equations that are corrected to higher order in the ratio of the poloidal Larmor radius to the minor radius, which requires evaluation of the diamagnetic corrections to Maxwellian equilibria. To study the momentum transport due to diamagnetic flow effects, three experimental observations of ion rotation are examined. First, a strong pressure gradient at the plasma edge is shown to result in a significant inward momentum transport due to the diamagnetic effect, which may explain the observed peaking of rotation in a high confinement mode. Second, the direction of momentum transport is shown to change as collisionality increases, which is qualitatively consistent with the observed reversal of intrinsic rotation by varying plasma density and current. Last, the dependence of the intrinsic momentum flux on the magnetic shear is found, and it may explain the observed rotation changes in the presence of lower hybrid current drive.
Kirchhoff prestack depth migration in orthorhombic velocity models with differently rotated tensors
Cerveny, Vlastislav
Kirchhoff prestack depth migration in orthorhombic velocity models with differently rotated tensors use the ray-based Kirchhoff prestack depth migration to calculate migrated sections in simple with a differently rotated tensor of elastic moduli. We apply the Kirchhoff prestack depth migration to single
Kirchhoff prestack depth migration in velocity models with and without rotation of the tensor of
Cerveny, Vlastislav
Kirchhoff prestack depth migration in velocity models with and without rotation of the tensor-mail: bucha@seis.karlov.mff.cuni.cz Summary We use the Kirchhoff prestack depth migration to calculate is limited to P-waves. Keywords 3-D Kirchhoff prestack depth migration, anisotropic velocity model, rotation
Kirchhoff prestack depth migration in triclinic velocity models with differently rotated tensors
Cerveny, Vlastislav
Kirchhoff prestack depth migration in triclinic velocity models with differently rotated tensors use the Kirchhoff prestack depth migration to calculate migrated sections in simple anisotropic rotations of the tensor of elastic moduli. We apply the Kirchhoff prestack depth migration to single- layer
Rotation-Robust Math Symbol Recognition and Retrieval Using Outer Contours and Image Subsampling
Zanibbi, Richard
Rotation-Robust Math Symbol Recognition and Retrieval Using Outer Contours and Image Subsampling the system with original Turning Function on the rotated InftyCDB-3 dataset. Keywords: Machine-Printed Math Symbol Recognition, Content-Based Math Symbol Retrieval 1. INTRODUCTION Recognition of math expression
Acoustic oscillations in rapidly rotating polytropic stars I. Effects of the centrifugal distortion
F. Lignieres; M. Rieutord; D. Reese
2006-04-13T23:59:59.000Z
A new non-perturbative method to compute accurate oscillation modes in rapidly rotating stars is presented. In this paper, the effect of the centrifugal force is fully taken into account while the Coriolis force is neglected. This assumption is valid when the time scale of the oscillation is much shorter than the inverse of the rotation rate and is expected to be suitable for high radial order p-modes of $\\delta$ Scuti stars. Axisymmetric p-modes have been computed in uniformly rotating polytropic models of stars. In the frequency and rotation range considered, we found that as rotation increases (i) the asymptotic structure of the non-rotating frequency spectrum is first destroyed then replaced by a new form of organization (ii) the mode amplitude tends to concentrate near the equator (iii) differences with perturbative methods become significant as soon as the rotation rate exceeds about fifteen percent of the Keplerian limit. The implications for the seismology of rapidly rotating stars are then discussed.
Zuo-Bing Wu
2008-03-17T23:59:59.000Z
In this paper, a method to construct topological template in terms of symbolic dynamics for the diamagnetic Kepler problem is proposed. To confirm the topological template, rotation numbers of invariant manifolds around unstable periodic orbits in a phase space are taken as an object of comparison. The rotation numbers are determined from the definition and connected with symbolic sequences encoding the periodic orbits in a reduced Poincar\\'e section. Only symbolic codes with inverse ordering in the forward mapping can contribute to the rotation of invariant manifolds around the periodic orbits. By using symbolic ordering, the reduced Poincar\\'e section is constricted along stable manifolds and a topological template, which preserves the ordering of forward sequences and can be used to extract the rotation numbers, is established. The rotation numbers computed from the topological template are the same as those computed from their original definition.
Ohmic energy confinement saturation and core toroidal rotation reversal in Alcator C-Mod plasmas
Rice, J. E.; Greenwald, M. J.; Podpaly, Y. A.; Reinke, M. L.; Hughes, J. W.; Howard, N. T.; Ma, Y.; Cziegler, I.; Ennever, P. C.; Ernst, D.; Fiore, C. L.; Gao, C.; Irby, J. H.; Marmar, E. S.; Porkolab, M.; Tsujii, N.; Wolfe, S. M. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States); Diamond, P. H. [UCSD, La Jolla, California 92903 (United States); Duval, B. P. [CRPP, EPFL, Lausanne 1015 (Switzerland)
2012-05-15T23:59:59.000Z
Ohmic energy confinement saturation is found to be closely related to core toroidal rotation reversals in Alcator C-Mod tokamak plasmas. Rotation reversals occur at a critical density, depending on the plasma current and toroidal magnetic field, which coincides with the density separating the linear Ohmic confinement regime from the saturated Ohmic confinement regime. The rotation is directed co-current at low density and abruptly changes direction to counter-current when the energy confinement saturates as the density is increased. Since there is a bifurcation in the direction of the rotation at this critical density, toroidal rotation reversal is a very sensitive indicator in the determination of the regime change. The reversal and confinement saturation results can be unified, since these processes occur in a particular range of the collisionality.
The radiative heat transfer between a rotating nanoparticle and a plane surface
Vahid Ameri; Mehdi Shafei Aporvari; Fardin Kheirandish
2015-06-03T23:59:59.000Z
Based on a microscopic approach, we propose a Lagrangian for the combined system of a rotating dielectric nanoparticle above a plane surface in the presence of electromagnetic vacuum fluctuations. In the framework of canonical quantization, the electromagnetic vacuum field is quantized in the presence of dielectric fields describing the nanoparticle and a semi-infinite dielectric with planar interface. The radiative heat power absorbed by the rotating nanoparticle is obtained and the result is in agreement with previous results when the the rotational frequency of the nanoparticle is zero or much smaller than the relaxation frequency of the dielectrics. The well known near field effect is reexamined and discussed in terms of the rotational frequency. The radiative heat power absorbed by the nanoparticle for well-known peak frequencies, is plotted in terms of the rotational frequency showing an interesting effect resembling a phase transition around a critical frequency, determined by the relaxation frequency of the dielectrics.
Limited spatial region for synchronous beam-wave interactions in rotating mode resonators
Velazco, J.E. (Microwave Research Laboratory, Department of Electric and Computer Engineering, George Mason University, Fairfax, Virginia 22030 (United States)); Mako, F.M. (FM Technologies, Inc., Fairfax, Virginia 22032 (United States))
1993-11-29T23:59:59.000Z
An electron beam passing along an axisymmetric static magnetic field under the presence of circularly polarized electromagnetic fields, launched in a suitable rotating mode resonator, can propagate as a growing helix. This helix rotates temporally with an angular velocity equal to that of the cavity's rotating mode. When the axial magnetic field is adjusted to obtain matching between the electrons gyrofrequency and fields rotating frequency, the electrons maintain phase coherence with the wave during the interaction. Synchronous beam-wave interactions will be shown to be limited to a spatial region near the resonator axis. This limited synchronous region results from the rotating-wave phase velocity exceeding the velocity of the particle beam.
Observation of the Larmor and Gouy Rotations with Electron Vortex Beams
Giulio Guzzinati; Peter Schattschneider; Konstantin Bliokh; Franco Nori; Jo Verbeeck
2013-02-25T23:59:59.000Z
Electron vortex beams carrying intrinsic orbital angular momentum (OAM) are produced in electron microscopes where they are controlled and focused using magnetic lenses. We observe various rotational phenomena arising from the interaction between the OAM and magnetic lenses. First, the Zeeman coupling, proportional to the OAM and magnetic field strength, produces an OAM-independent Larmor rotation of a mode superposition inside the lens. Second, hen passing through the focal plane, the electron beam acquires an additional Gouy phase dependent on the absolute value of the OAM. This brings about the Gouy rotation of the superposition image proportional to the sign of the OAM. A combination of the Larmor and Gouy effects can result in the addition (or subtraction) of rotations, depending on the OAM sign. This behaviour is unique to electron vortex beams and has no optical counterpart, as Larmor rotation occurs only for charged particles. Our experimental results are in agreement with recent theoretical predictions.
Four-Hair Relations for Differentially Rotating Neutron Stars in the Weak-Field Limit
Joseph Bretz; Kent Yagi; Nicolas Yunes
2015-07-08T23:59:59.000Z
The opportunity to study physics at supra-nuclear densities through X-ray observations of neutron stars has led to in-depth investigations of certain approximately universal relations that can remove degeneracies in pulse profile models. One such set of relations determines all of the multipole moments of a neutron star just from the first three (the mass monopole, the current dipole and the mass quadrupole moment) approximately independently of the equation of state. These three-hair relations were found to hold in neutron stars that rotate rigidly, as is the case in old pulsars, but neutron stars can also rotate differentially, as is the case for proto-neutron stars and hypermassive transient remnants of binary mergers. We here extend the three-hair relations to differentially rotating stars for the first time with a generic rotation law using two approximations: a weak-field scheme (an expansion in powers of the neutron star compactness) and a perturbative differential rotation scheme (an expansion about rigid rotation). These approximations allow us to analytically derive approximately universal relations that allow us to determine all of the multipole moments of a (perturbative) differentially rotating star in terms of only the first four moments. These new four-hair relations for differentially rotating neutron stars are found to be approximately independent of the equation of state to a higher degree than the three-hair relations for uniformly rotating stars. Our results can be instrumental in the development of four-hair relations for rapidly differentially rotating stars in full General Relativity using numerical simulations.
Fu, Wen-Lung
2005-08-29T23:59:59.000Z
This study experimentally investigates the effects of rotation, the buoyancy force, and the channel aspect ratio on heat transfer in two-pass rotating rectangular channels. The experiments are conducted with two surface ...
On the Doppler effect for photons in rotating systems
Giuliani, Giuseppe
2015-01-01T23:59:59.000Z
The analysis of the Doppler effect for photons in rotating systems, studied using the M\\"ossbauer effect, confirms the general conclusions of a previous paper dedicated to experiments with photons emitted/absorbed by atoms/nuclei in inertial flight. The wave theory of light is so deeply rooted that it has been--and currently is--applied to describe phenomena in which the fundamental entities at work are discrete (photons). The fact that the wave theory of light can describe one aspect of these phenomena can not overshadow two issues: the corpuscular theory of light, firstly applied to the Doppler effect for photons by Schr\\"odinger in 1922, is by far more complete since it describes all the features of the studied phenomena; the wave theory can be used only when the number of photons at work is statistically significant. The disregard of basic methodological criteria may appear as a minor fault. However, the historical development of quantum physics shows that the predominance of the wave theory of radiation,...
Teleparallel Energy-Momentum Distribution of Locally Rotationally Symmetric Spacetimes
M. Jamil Amir; Tahir Nazir
2014-12-11T23:59:59.000Z
In this paper, we explore the energy-momentum distribution of locally rotationally symmetric (LRS) spacetimes in the context of the teleparallel theory of gravity by considering the three metrics, I, II and III, representing the whole class of LRS sapcetimes. In this regard, we use the teleparallel versions of the Einstein, Landau-Lifshitz, Bergmann-Thomson, and M$\\ddot{o}$ller prescriptions. The results show that the momentum density components for the Einstein, Bergmann-Thomson, and M$\\ddot{o}$ller prescriptions turn out to be same in all cases of the metrics I, II and III, but are different from those of the Landau- Lifshitz prescription, while the energy components remain the same for these three prescriptions only in all possible cases of the metrics I and II. We mention here that the M$\\ddot{o}$ller energy-momentum distribution is independent of the coupling constant $\\lambda$; that is, these results are valid for any teleparallel models.
Hydrodynamics of rapidly rotating superfluid neutron stars with mutual friction
A. Passamonti; N. Andersson
2010-04-26T23:59:59.000Z
We study time evolutions of superfluid neutron stars, focussing on the nature of the oscillation spectrum, the effect of mutual friction force on the oscillations and the hydrodynamical spin-up phase of pulsar glitches. We linearise the dynamical equations of a Newtonian two-fluid model for rapidly rotating backgrounds. In the axisymmetric equilibrium configurations, the two fluid components corotate and are in beta-equilibrium. We use analytical equations of state that generate stratified and non-stratified stellar models, which enable us to study the coupling between the dynamical degrees of freedom of the system. By means of time evolutions of the linearised dynamical equations, we determine the spectrum of axisymmetric and non-axisymmetric oscillation modes, accounting for the contribution of the gravitational potential perturbations, i.e. without adopting the Cowling approximation. We study the mutual friction damping of the superfluid oscillations and consider the effects of the non-dissipative part of the mutual friction force on the mode frequencies. We also provide technical details and relevant tests for the hydrodynamical model of pulsar glitches discussed by Sidery, Passamonti and Andersson (2010). In particular, we describe the method used to generate the initial data that mimic the pre-glitch state, and derive the equations that are used to extract the gravitational-wave signal.
Characterization of invariant patterns in a slowly rotated granular tumbler
Leonardo Reyes; Oscar Pérez; Claudia Colonnello; Angélica Goncalves; Haydn Barros; Iván Sánchez; Gustavo Gutiérrez
2014-09-23T23:59:59.000Z
We report experimental results of the pattern developed by a mixture of two types of grains in a triangular rotating tumbler operating in the avalanche regime. At the centroid of the triangular tumbler an invariant zone appears where the grains do not move relative to the tumbler. We characterize this invariant zone by its normalized area, $A_i$, and its circularity index as a function of the normalized filling area $A$. We find a critical filling area so that only for $A>A_c$ invariant zones are obtained. These zones scale as $A_i\\sim (A-A_c)^2$ near $A_c$. We have obtained a maximum in the circularity index for $A\\approx 0.8$, for which the shape of the invariant zone is closer to a circular one. The experimental results are reproduced by a simple model which, based on the surface position, accounts for all the possible straight lines within the triangle that satisfy the condition of constant $A$. We have obtained an analytic expression for the contour of the invariant zone.
Muon spin rotation studies of niobium for superconducting RF applications
Grassellino, A; Kolb, P; Laxdal, R; Lockyer, N S; Longuevergne, D; Sonier, J E
2013-01-01T23:59:59.000Z
In this work we investigate superconducting properties of niobium samples via application of the muon spin rotation/relaxation (muSR) technique. We employ for the first time the muSR technique to study samples that are cutout from large and small grain 1.5 GHz radio frequency (RF) single cell niobium cavities. The RF test of these cavities was accompanied by full temperature mapping to characterize the RF losses in each of the samples. Results of the muSR measurements show that standard cavity surface treatments like mild baking and buffered chemical polishing (BCP) performed on the studied samples affect their surface pinning strength. We find an interesting correlation between high field RF losses and field dependence of the sample magnetic volume fraction measured via muSR. The muSR line width observed in ZF-muSR measurements matches the behavior of Nb samples doped with minute amounts of Ta or N impurities. An upper bound for the upper critical field Hc2 of these cutouts is found.
Janzen, V P; Andrews, H R; Ball, G C; Cameron, J A; Cromaz, M; DeGraaf, J; Flibotte, S; Galindo-Uribarri, A; Hackman, G; Headly, D M; Jonkman, J; Mullins, S M; Radford, D C; Ragnarsson, I; Rodríguez, J L; Svensson, C E; Waddington, J C; Ward, D; Zwartz, G
1996-01-01T23:59:59.000Z
Properties of rotational bands at the spin limit in A $\\sim$ 50, A $\\sim$ 65 and A $\\sim$ 110 nuclei
Golden, A; Wasserman, J; Bania, T; Stratton, J
2014-01-01T23:59:59.000Z
Daily Evaluations During a Fourth Year Elective Rotation inNY Background: The majority of fourth year medical students’
Neutron Emission Spectroscopy of Fuel Ion Rotation and Fusion Power Components Demonstrated in the Trace Tritium Experiments at JET
Slowly rotating superfluid neutron stars with isospin dependent entrainment in a two-fluid model
Apurba Kheto; Debades Bandyopadhyay
2015-02-13T23:59:59.000Z
We investigate the slowly rotating general relativistic superfluid neutron stars including the entrainment effect in a two-fluid model, where one fluid represents the superfluid neutrons and the other is the charge-neutral fluid called the proton fluid, made of protons and electrons. The equation of state and the entrainment effect between the superfluid neutrons and the proton fluid are computed using a relativistic mean field (RMF) model where baryon-baryon interaction is mediated by the exchange of $\\sigma$, $\\omega$, and $\\rho$ mesons and scalar self interactions are also included. The equations governing rotating neutron stars in the slow rotation approximation are second order in rotational velocities of neutron and proton fluids. We explore the effects of the isospin dependent entrainment and the relative rotation between two fluids on the global properties of rotating superfluid neutron stars such as mass, shape, and the mass shedding (Kepler) limit within the RMF model with different parameter sets. It is observed that for the global properties of rotating superfluid neutron stars in particular, the Kepler limit is modified compared with the case that does not include the contribution of $\\rho$ mesons in the entrainment effect.
Measuring the rotation period distribution of field M-dwarfs with Kepler
McQuillan, Amy; Mazeh, Tsevi
2013-01-01T23:59:59.000Z
We have analysed 10 months of public data from the Kepler space mission to measure rotation periods of main-sequence stars with masses between 0.3 and 0.55 M_sun. To derive the rotational period we introduce the autocorrelation function and show that it is robust against phase and amplitude modulation and residual instrumental systematics. Of the 2483 stars examined, we detected rotation periods in 1570 (63.2%), representing an increase of a factor ~ 30 in the number of rotation period determination for field M-dwarfs. The periods range from 0.37-69.7 days, with amplitudes ranging from 1.0-140.8 mmags. The rotation period distribution is clearly bimodal, with peaks at ~ 19 and ~ 33 days, hinting at two distinct waves of star formation, a hypothesis that is supported by the fact that slower rotators tend to have larger proper motions. The two peaks of the rotation period distribution form two distinct sequences in period-temperature space, with the period decreasing with increasing temperature, reminiscent of ...
Yunyun Li; Nianbei Li; Baowen Li
2015-01-29T23:59:59.000Z
In contrary to other 1D momentum-conserving lattices such as the Fermi-Pasta-Ulam $\\beta$ (FPU-$\\beta$) lattice, the 1D coupled rotator lattice is a notable exception which conserves total momentum while exhibits normal heat conduction behavior. The temperature behavior of the thermal conductivities of 1D coupled rotator lattice had been studied in previous works trying to reveal the underlying physical mechanism for normal heat conduction. However, two different temperature behaviors of thermal conductivities have been claimed for the same coupled rotator lattice. These different temperature behaviors also intrigue the debate whether there is a phase transition of thermal conductivities as the function of temperature. In this work, we will revisit the temperature dependent thermal conductivities for the 1D coupled rotator lattice. We find that the temperature dependence follows a power law behavior which is different with the previously found temperature behaviors. Our results also support the claim that there is no phase transition for 1D coupled rotator lattice. We also give some discussion about the similarity of diffusion behaviors between the 1D coupled rotator lattice and the single kicked rotator also called the Chirikov standard map.
FURTHER RESULTS FROM THE GALACTIC O-STAR SPECTROSCOPIC SURVEY: RAPIDLY ROTATING LATE ON GIANTS
Walborn, Nolan R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); MaIz Apellaniz, Jesus; Sota, Alfredo; Alfaro, Emilio J. [Instituto de Astrofisica de Andalucia-CSIC, Glorieta de la Astronomia s/n, 18008 Granada (Spain); Morrell, Nidia I. [Las Campanas Observatory, Observatories of the Carnegie Institution of Washington, Casilla 601, La Serena (Chile); Barba, Rodolfo H.; Arias, Julia I. [Departamento de Fisica, Universidad de La Serena, Cisternas 1200 Norte, La Serena (Chile); Gamen, Roberto C., E-mail: walborn@stsci.edu, E-mail: jmaiz@iaa.es, E-mail: sota@iaa.es, E-mail: emilio@iaa.es, E-mail: nmorrell@lco.cl, E-mail: rbarba@dfuls.cl, E-mail: julia@dfuls.cl, E-mail: rgamen@fcaglp.unlp.edu.ar [Instituto de Astrofisica de La Plata-CONICET and Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata (Argentina)
2011-11-15T23:59:59.000Z
With new data from the Galactic O-Star Spectroscopic Survey, we confirm and expand the ONn category of late-O, nitrogen-enriched (N), rapidly rotating (n) giants. In particular, we have discovered two 'clones' (HD 102415 and HD 117490) of one of the most rapidly rotating O stars previously known (HD 191423, 'Howarth's Star'). We compare the locations of these objects in the theoretical H-R diagram to those of slowly rotating ON dwarfs and supergiants. All ON giants known to date are rapid rotators, whereas no ON dwarf or supergiant is, but all ON stars are small fractions of their respective spectral-type/luminosity-class/rotational subcategories. The ONn giants, displaying both substantial processed material and high rotation at an intermediate evolutionary stage, may provide significant information about the development of these properties. They may have preserved high initial rotational velocities or may have been spun up by terminal-age main-sequence core contraction; alternatively, and perhaps more likely, they may be products of binary mass transfer. At least some of them are also runaway stars.
A View through Faraday's fog: Parsec scale rotation measures in AGN
R. T. Zavala; G. B. Taylor
2003-02-18T23:59:59.000Z
Rotation measure observations of 9 quasars, 4 BL Lacertae objects, and 3 radio galaxies are presented. The rest frame rotation measures in the cores of the quasars and the jets of the radio galaxy M87 are several thousand radians per meter squared. The BL Lacertae objects and the jets of the quasars have rest frame rotation measures of a few hundred radians per meter squared. A nuclear rotation measure of 500 radians per meter squared in the rest frame is suggested as the dividing line between quasar and BL Lacertae objects. The substantial rotation measures of the BL Lacertae objects and quasars cast doubt on the previous polarization position angle investigations of these objects at frequencies of 15 GHz or less. BL Lacertae itself has a rotation measure that varies in time, similar to the behavior observed for the quasars 3C273 and 3C279. A simple model with magnetic fields of 40 microgauss or less can account for the observed rotation measures.
A View through Faraday's Fog 2: Parsec Scale Rotation Measures in 40 AGN
R. T. Zavala; G. B. Taylor
2004-05-27T23:59:59.000Z
Results from a survey of the parsec scale Faraday rotation measure properties for 40 quasars, radio galaxies and BL Lac objects are presented. Core rotation measures for quasars vary from approximately 500 to several thousand radians per meter squared. Quasar jets have rotation measures which are typically 500 radians per meter squared or less. The cores and jets of the BL Lac objects have rotation measures similar to those found in quasar jets. The jets of radio galaxies exhibit a range of rotation measures from a few hundred radians per meter squared to almost 10,000 radians per meter squared for the jet of M87. Radio galaxy cores are generally depolarized, and only one of four radio galaxies (3C-120) has a detectable rotation measure in the core. Several potential identities for the foreground Faraday screen are considered and we believe the most promising candidate for all the AGN types considered is a screen in close proximity to the jet. This constrains the path length to approximately 10 parsecs, and magnetic field strengths of approximately 1 microGauss can account for the observed rotation measures. For 27 out of 34 quasars and BL Lacs their optically thick cores have good agreement to a lambda squared law. This requires the different tau = 1 surfaces to have the same intrinsic polarization angle independent of frequency and distance from the black hole.
THE EFFECTS OF ROTATION ON s-PROCESS NUCLEOSYNTHESIS IN ASYMPTOTIC GIANT BRANCH STARS
Piersanti, L.; Cristallo, S.; Straniero, O., E-mail: piersanti@oa-teramo.inaf.it [INAF-Osservatorio Astronomico di Collurania, via Maggini snc, I-64100 Teramo (Italy)
2013-09-10T23:59:59.000Z
In this paper, we analyze the effects induced by rotation on low-mass asymptotic giant branch stars. We compute two sets of models, M = 2.0 M{sub Sun} at [Fe/H] = 0 and M = 1.5 M{sub Sun} at [Fe/H] = -1.7, by adopting main-sequence rotation velocities in the range 0-120 km s{sup -1}. At high metallicity, we find that the Goldreich-Schubert-Fricke instability, active at the interface between the convective envelope and the rapid rotating core, contaminates the {sup 13}C-pocket (the major neutron source) with {sup 14}N (the major neutron poison), thus reducing the neutron flux available for the synthesis of heavy elements. As a consequence, the yields of heavy-s elements (Ba, La, Nd, Sm) and, to a lesser extent, those of light-s elements (Sr, Y, Zr) decrease with increasing rotation velocities up to 60 km s{sup -1}. However, for larger initial rotation velocities, the production of light-s and, to a lesser extent, that of heavy-s, begins again to increase, due to mixing induced by meridional circulations. At low metallicity, the effects of meridional circulations are important even at rather low rotation velocity. The combined effect of the Goldreich-Schubert-Fricke instability and meridional circulations determines an increase of light-s and, to a lesser extent, heavy-s elements, while lead is strongly reduced. For both metallicities, the rotation-induced instabilities active during the interpulse phase reduce the neutron-to-seed ratio, so that the spectroscopic indexes [hs/ls] and [Pb/hs] decrease by increasing the initial rotation velocity. Our analysis suggests that rotation could explain the spread in the s-process indexes, as observed in s-process enriched stars at different metallicities.
Sensitivity analysis of the solar rotation to helioseismic data from GONG, GOLF and MDI observations
A. Eff-Darwich; S. G. Korzennik; S. J. Jimenez-Reyes; R. A. Garcia
2008-02-25T23:59:59.000Z
Accurate determination of the rotation rate in the radiative zone of the sun from helioseismic observations requires rotational frequency splittings of exceptional quality as well as reliable inversion techniques. We present here inferences based on mode parameters calculated from 2088-days long MDI, GONG and GOLF time series that were fitted to estimate very low frequency rotational splittings (nu < 1.7 mHz). These low frequency modes provide data of exceptional quality, since the width of the mode peaks is much smaller than the rotational splitting and hence it is much easier to separate the rotational splittings from the effects caused by the finite lifetime and the stochastic excitation of the modes. We also have implemented a new inversion methodology that allows us to infer the rotation rate of the radiative interior from mode sets that span l=1 to 25. Our results are compatible with the sun rotating like a rigid solid in most of the radiative zone and slowing down in the core (R_sun < 0.2). A resolution analysis of the inversion was carried out for the solar rotation inverse problem. This analysis effectively establishes a direct relationship between the mode set included in the inversion and the sensitivity and information content of the resulting inferences. We show that such an approach allows us to determine the effect of adding low frequency and low degree p-modes, high frequency and low degree p-modes, as well as some g-modes on the derived rotation rate in the solar radiative zone, and in particular the solar core. We conclude that the level of uncertainties that is needed to infer the dynamical conditions in the core when only p-modes are included is unlikely to be reached in the near future, and hence sustained efforts are needed towards the detection and characterization of g-modes.
Modeling the profitability of power production from short-rotation woody crops in Sub-Saharan Africa
Vermont, University of
Modeling the profitability of power production from short-rotation woody crops in Sub Available online xxx Keywords: Bioenergy Electric power production Short-rotation woody crops Sub the profitability of power production from short-rotation woody crops in Sub-Saharan Africa, Biomass and Bioenergy
Fitzpatrick, Richard
Bifurcated states of a rotating tokamak plasma in the presence of a static error-field Richard and nonlinear response of a rotating tokamak plasma to a resonant error-field Phys. Plasmas 21, 092513 (2014); 10.1063/1.4896244 Neoclassical momentum transport in an impure rotating tokamak plasma Phys. Plasmas
Wave Properties of Plasma Surrounding the Event Horizon of a Non-Rotating Black Hole
M. Sharif; G. Mustafa
2008-09-09T23:59:59.000Z
We have studied the wave properties of the cold and isothermal plasma in the vicinity of the Schwarzschild black hole event horizon. The Fourier analyzed perturbed 3+1 GRMHD equations are taken on the basis of which the complex dispersion relations are obtained for non-rotating, rotating non-magnetized and rotating magnetized backgrounds. The propagation and attenuation vectors along with the refractive index are obtained (shown in graphs) to study the dispersive properties of the medium near the event horizon. The results show that no information can be obtained from the Schwarzschild magnetosphere. Further, the pressure ceases the existence of normal dispersion of waves.
Rotational Augmentation Disparities in the MEXICO and UAE Phase VI Experiments: Preprint
Schreck, S.; Sant, T.; Micallef, D.
2010-05-01T23:59:59.000Z
Wind turbine structures and components suffer excessive loads and premature failures when key aerodynamic phenomena are not well characterized, fail to be understood, or are inaccurately predicted. Turbine blade rotational augmentation remains incompletely characterized and understood, thus limiting robust prediction for design. Pertinent rotational augmentation research including experimental, theoretical, and computational work has been pursued for some time, but large scale wind tunnel testing is a relatively recent development for investigating wind turbine blade aerodynamics. Because of their large scale and complementary nature, the MEXICO and UAE Phase VI wind tunnel experiments offer unprecedented synergies to better characterize and understand rotational augmentation of blade aerodynamics.
Invariant quantities of a Mueller matrix under rotation and retarder transformations
Gil, Jose J
2015-01-01T23:59:59.000Z
Mueller matrices are defined with respect to appropriate Cartesian reference frames for the representation of the states of polarization of the input and output electromagnetic waves. The polarimetric quantities that are invariant under rotations of the said reference frames about the respective directions of propagation (rotation transformations) provide particularly interesting physical information. Moreover, certain properties are also invariant with respect to the action of birefringent devices located at both sides of the medium under consideration (retarder transformations). The polarimetric properties that remain invariant under rotation and retarder transformations are analyzed and interpreted, providing significant parameterizations of Mueller matrices in terms of meaningful physical quantities.
Fast mode of rotating atoms in one-dimensional lattice rings
T. Wang; S. F. Yelin
2007-06-11T23:59:59.000Z
We study the rotation of atoms in one-dimensional lattice rings. In particular, the "fast mode", where the ground state atoms rotate faster than the stirring rotating the atoms, is studied both analytically and numerically. The conditions for the transition to the fast mode are found to be very different from that in continuum rings. We argue that these transition frequencies remain unchanged for bosonic condensates described in a mean field. We show that Fermionic interaction and filling factor have a significant effect on the transition to the fast mode, and Pauli principle may suppress it altogether.
Phase-kicked control of counter-rotating interactions in the quantum Rabi model
Jin-Feng Huang; C. K. Law
2014-07-17T23:59:59.000Z
We present an interaction scheme to control counter-rotating terms in the quantum Rabi model. We show that by applying a sequence of $\\pi/2$ phase kicks to a two-level atom and a single mode quantized field, the natural dynamics of the Rabi model can be interrupted in a way that counter-rotating transitions can be significantly enhanced. This is achieved by a suitable timing of the phase kicks determined by a phase matching condition. If the time between successive kicks is sufficiently short, our scheme is turned into a dynamical decoupling problem in which the effects of counter-rotating terms can be strongly suppressed under ultrastrong coupling.
Cole, D.M.; Koch, P.
1995-12-01T23:59:59.000Z
This paper suggests solution for a longstanding problem in managing lodgepole pine forests- that of managing individual stands to reach their planned rotation age, despite serious hazard from bark beetles and wildfire. The management regimes presented yield merchantable thinning products. The 80-year sawtimber rotation can be achieved using these management recommendation. Thinning at 30 years of age is central to achieving the recommended alternative management regimes. The authors suggest that agencies give roundwood operators a portion of the thinning stemwood as payment. Management regimes that provide attainable rotations are presented in summary tables, by three site index classes and a number of initial stand density classes.
Controlling the collimation and rotation of hydromagnetic disk winds
Ralph E. Pudritz; Conrad Rogers; Rachid Ouyed
2005-08-12T23:59:59.000Z
(Abriged) We present a comprehensive set of axisymmetric, time-dependent simulations of jets from Keplerian disks whose mass loading as a function of disk radius is systematically changed. For a reasonable model for the density structure and injection speed of the underlying accretion disk, mass loading is determined by the radial structure of the disk's magnetic field structure. We vary this structure by using four different magnetic field configurations, ranging from the "potential" configuration (Ouyed&Pudritz 1997), to the increasingly more steeply falling Blandford&Payne (1982) and Pelletier&Pudritz (1992) models, and ending with a quite steeply raked configuration that bears similarities to the Shu X-wind model. We find that the radial distribution of the mass load has a profound effect on both the rotational profile of the underlying jet as well as the degree of collimation of its outflow velocity and magnetic field lines. We show analytically, and confirm by our simulations, that the collimation of a jet depends on its radial current distribution, which in turn is prescribed by the mass load. Models with steeply descending mass loads have strong toroidal fields, and these collimate to cylinders (this includes the Ouyed-Pudritz and Blandford-Payne outflows). On the other hand, the more gradually descending mass load profiles (the PP92 and monopolar distributions) have weaker toroidal fields, and these result in wide-angle outflows with parabolic collimation. We also present detailed structural information about jets such as their radial profiles of jet density, toroidal magnetic field, and poloidal jet speed, as well as an analysis of the bulk energetics of our different simulations.
Egor Babaev
2009-11-17T23:59:59.000Z
I show that the usual model of the rotational response of a neutron star, which predicts rotation-induced neutronic vortices and no rotation-induced protonic vortices, does not hold (i) beyond a certain threshold of entrainment interaction strength nor (ii) in case of nonzero $\\Sigma^-$ hyperon gap. I demonstrate that in both these cases the rotational response involves creation of phase windings in electrically charged condensate. Lattices of bound states of vortices which are caused these effects can (for a range of parameters) strongly reduce the interaction between rotation-induced vortices with magnetic-field carrying superconducting components.
Zero-point fluctuations in rotation: Perpetuum mobile of the fourth kind without energy transfer
M. N. Chernodub
2013-02-03T23:59:59.000Z
We discuss a simple Casimir-type device for which the rotational energy reaches its global minimum when the device rotates about a certain axis rather than remains static. This unusual property is a direct consequence of the fact that the moment of inertia of zero-point vacuum fluctuations is a negative quantity (the rotational vacuum effect). Moreover, the device does not produce any work despite the fact that its equilibrium ground state corresponds to a permanent rotation. Counterintuitively, the device has no internally moving mechanical parts while its very existence is consistent with the laws of thermodynamics. We point out that such devices may possibly be constructed using carbon nanotubes. We call this "zero-point-driven" device as the perpetuum mobile of the fourth kind.
Mechanical design of a contra-rotating propeller assembly for a small underwater ROV
Stefanov-Wagner, Thaddeus (Thaddeus J.)
2006-01-01T23:59:59.000Z
A project was undertaken to design and build a contra-rotating propeller assembly for a small underwater remotely operated vehicle (ROV), with the intent of commissioning a production run at a later time. The desired ...
Numerical Study of Geometry and Rotation Dependence on the Flow in Labyrinth Seals
Yamsani, Vamshi Krishna
2011-10-21T23:59:59.000Z
A computational study was conducted on the flow, both compressible and incompressible, in a labyrinth seal at various geometries and rotation rates. The computations were performed using the commercial software Fluent® which solves the k-? model...
Paris-Sud XI, Université de
Primary crossflow vortices, secondary absolute instabilities and their control in the rotating patterns of crossflow vortices are derived by employing asymptotic techniques. This approach accounts three-dimensional velocity profiles, are subject to inviscid crossflow in- stabilities and rapidly
Graf, A.; May, M.; Beiersdorfer, P.; Magee, E.; Lawrence, M.; Rice, J. [University of California, Davis, California 95616 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2004-10-01T23:59:59.000Z
We present a high throughput (f/3) visible (3500-7000 A) Doppler spectrometer for toroidal rotation velocity measurements of the Alcator C-Mod tokamak plasma. The spectrometer has a temporal response of 1 ms and a rotation velocity sensitivity of {approx}10{sup 5} cm/s. This diagnostic will have a tangential view and map out the plasma rotation at several locations along the outer half of the minor radius (r/a>0.5). The plasma rotation will be determined from the Doppler shifted wavelengths of D{sub {alpha}} and magnetic and electric dipole transitions of highly ionized impurities in the plasma. The fast time resolution and high spectral resolving power are possible due to a 6 in. diam circular transmission grating that is capable of {lambda}/{delta}{lambda}{approx}15 500 at 5769 A in conjunction with a 50 {mu}m slit.
Graf, A; May, M; Beiersdorfer, P; Magee, E; Lawrence, M; Terry, J; Rice, J
2004-04-29T23:59:59.000Z
We present a high throughput (f/3) visible (3500 - 7000 Angstrom) Doppler spectrometer for toroidal rotation velocity measurements of the Alcator C-Mod tokamak plasma. The spectrometer has a temporal response of 1 ms and a rotation velocity sensitivity of {approx}10{sup 5} cm/s. This diagnostic will have a tangential view and map out the plasma rotation at several locations along the outer half of the minor radius (r/a > 0.5). The plasma rotation will be determined from the Doppler shifted wavelengths of D{sub alpha} and magnetic and electric dipole transitions of highly ionized impurities in the plasma. The fast time resolution and high spectral resolving power are possible due to a 6' diameter circular transmission grating that is capable of {lambda}/{Delta}{lambda} {approx} 15500 at 5769 Angstrom in conjunction with a 50 {micro}m slit.
M-DWARF RAPID ROTATORS AND THE DETECTION OF RELATIVELY YOUNG MULTIPLE M-STAR SYSTEMS
Swift, J.
We have searched the Kepler light curves of ~3900 M-star targets for evidence of periodicities that indicate, by means of the effects of starspots, rapid stellar rotation. Several analysis techniques, including Fourier ...
Two-Dimensional Image Rotation Ivan Sterling 1 and Thomas Sterling 2
Sterling, Ivan
Two-Dimensional Image Rotation Ivan Sterling 1 and Thomas Sterling 2 1 Department of Mathematics scanning of a document, such as an engineering drawing. When the drawing is fed into the scanner, it may
Continuous surveillance of points by rotating floodlights J. M. Diaz-Ba~nez2
Urrutia, Jorge
scheduling; illumination; rotating sensors; coverage. 1 Introduction Art gallery theory and illumination by the University of Denver John Evans Research Fund. 5 Escuela de Ingenier´ia Civil en Inform´atica, Universidad de
5D Einstein-Maxwell solitons and concentric rotating dipole black rings
Stoytcho Yazadjiev
2008-05-12T23:59:59.000Z
We discuss the application of the solitonic techniques to the 5D Einstein-Maxwell gravity. As an illustration we construct an exact solution describing two concentric rotating dipole black rings. The properties of the solution are investigated.
Energy Loss Distribution in the Taylor-Couette Flow between Concentric Rotating Cylinders
Dou, H S; Phan-Thien, N; Yeo, K S; Dou, Hua-Shu; Khoo, Boo Cheong; Phan-Thien, Nhan; Yeo, Khoon Seng
2005-01-01T23:59:59.000Z
The distribution of energy loss due to viscosity friction in plane Couette flow and Taylor-Couette Flow between concentric rotating cylinders are studied in detail for various flow conditions. The energy loss is related to the industrial processes in some fluid delivery devices and has significant influence on the flow efficiency, flow stability, turbulent transition, mixing, and heat transfer behaviours, etc. Therefore, it is very helpful to know about the energy loss distribution in the flow domain and to know its influence on the flow for understanding the flow physics. The calculation method of the energy loss distribution in the Taylor-Couette Flow between concentric rotating cylinders has not been found in open literature. In this note, the principle and the calculation are given for single cylinder rotating of inner or outer cylinder, and counter and same direction rotating of two cylinders. For comparison, the distribution of energy loss in a plane Couette flow is also derived for various flow conditi...
Chu, Shih-I; Dalgarno, A.
1975-08-01T23:59:59.000Z
The effective close-coupling method of Rabitz is tested and used to calculate the angular distributions of the elastic and inelastic scattering of molecular hydrogen in collision with atomic hydrogen when rotational transitions may occur...
High-lying collective rotational states in Ba nuclei: Search for Jacobi Shapes.
Benzoni, Giovanna
High-lying collective rotational states in Ba nuclei: Search for Jacobi Shapes. G.Benzoni1 , A as a function of spin and compared with the liquid drop predictions including the Jacobi phase transition. 1
Design and operation of a counter-rotating aspirated compressor blowdown test facility
Parker, David V. (David Vickery)
2005-01-01T23:59:59.000Z
A unique counter-rotating aspirated compressor was tested in a blowdown facility at the Gas Turbine Laboratory at MIT. The facility expanded on experience from previous blowdown turbine and blowdown compressor experiments. ...
Consider Steam Turbine Drives for Rotating Equipment - Steam Tip Sheet #21
None
2012-01-01T23:59:59.000Z
This revised AMO tip sheet on steam turbine drives for rotating equipment provides how-to advice for improving the system using low-cost, proven practices and technologies.
A two-phase spherical electric machine for generating rotating uniform magnetic fields
Lawler, Clinton T. (Clinton Thomas)
2007-01-01T23:59:59.000Z
This thesis describes the design and construction of a novel two-phase spherical electric machine that generates rotating uniform magnetic fields, known as a fluxball machine. Alternative methods for producing uniform ...
Snively, Michael John
2011-01-01T23:59:59.000Z
The mechanisms that lead to bulk flow within a ferrofluid-filled container subjected to a rotating uniform magnetic field are experimentally studied. There are two prevailing theories: spin diffusion theory and flow due ...
Design of compliant mechanisms for attenuation of unidirectional vibrations in rotational systems
Szczesny, Spencer E., 1981-
2005-01-01T23:59:59.000Z
The purpose of this research was to generate the knowledge required to design compliant mechanisms that (1) attenuate undesired small-motion angular vibrations in rotational power transmission systems and (2) preserve the ...
Analogies of Ocean/Atmosphere Rotating Fluid Dynamics with Gyroscopes: Teaching Opportunities
Haine, Thomas W. N.
The dynamics of the rotating shallow-water (RSW) system include geostrophic f low and inertial oscillation. These classes of motion are ubiquitous in the ocean and atmosphere. They are often surprising to people at first ...
Oscillation of a Rotating Levitated Droplet: Analysis with a Mechanical Model
Kitahata, Hiroyuki; Koyano, Yuki; Matsumoto, Satoshi; Nishinari, Katsuhiro; Watanabe, Tadashi; Hasegawa, Koji; Kanagawa, Tetsuya; Kaneko, Akiko; Abe, Yutaka
2015-01-01T23:59:59.000Z
A droplet of millimeter-to-centimeter scale can exhibit electrostatic levitation, and such levitated droplets can be used for the measurement of the surface tension of the liquids by observing the characteristic frequency of oscillatory deformation. In the present study, a simple mechanical model is proposed by considering a single mode of oscillation in the ellipsoidal deformation of a levitated rotating droplet. By measuring the oscillation frequency with respect to the rotational speed and oscillation amplitude, it is expected that the accuracy of the surface tension measurement could be improved. Using the proposed model, the dependences of the characteristic frequency of oscillatory deformation and the averaged aspect ratio are calculated with respect to the rotational angular velocity of a rotating droplet. These dependences are found to be consistent with the experimental observations.
Apparatus and method for forming a workpiece surface into a non-rotationally symmetric shape
Dow, Thomas A. (Raleigh, NC); Garrard, Kenneth P. (Raleigh, NC); Moorefield, II, George M. (Raleigh, NC); Taylor, Lauren W. (Cary, NC)
1995-11-21T23:59:59.000Z
A turning machine includes a controller for generating both aspherical and non-symmetrical shape components defining the predetermined shape, and a controller for controlling a spindle and a positionable cutting blade to thereby form a predetermined non-rotationally symmetric shape in a workpiece surface. The apparatus includes a rotatable spindle for rotatably mounting the workpiece about an axis, a spindle encoder for sensing an angular position of the rotating workpiece, the cutting blade, and radial and transverse positioners for relatively positioning the cutting blade and workpiece along respective radial and transverse directions. The controller cooperates with a fast transverse positioner for positioning the cutting blade in predetermined varying transverse positions during a revolution of the workpiece.
Low torque hydrodynamic lip geometry for bi-directional rotation seals
Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)
2009-07-21T23:59:59.000Z
A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.
Low torque hydrodynamic lip geometry for bi-directional rotation seals
Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)
2011-11-15T23:59:59.000Z
A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.
Global Existence and Long-Time Asymptotics for Rotating Fluids in a 3D layer
Gallay, Thierry
Global Existence and Long-Time Asymptotics for Rotating Fluids in a 3D layer Thierry Gallay thierry.gallay@ujf-grenoble.fr Violaine Roussier-Michon Institut de MathÂ´ematiques de Toulouse (UMR CNRS
Global Existence and LongTime Asymptotics for Rotating Fluids in a 3D layer
Gallay, Thierry
Global Existence and LongÂTime Asymptotics for Rotating Fluids in a 3D layer Thierry Gallay thierry.gallay@ujfÂgrenoble.fr Violaine RoussierÂMichon Institut de Mathâ??ematiques de Toulouse (UMR CNRS
NON-GAUSSIAN STATISTICS AND STELLAR ROTATIONAL VELOCITIES OF MAIN-SEQUENCE FIELD STARS
Carvalho, J. C.; Do Nascimento, J. D.; Silva, R.; De Medeiros, J. R. [Universidade Federal do Rio Grande do Norte, UFRN, Departamento de Fisica, C. P. 1641, Natal, RN 59072-970 (Brazil)
2009-05-01T23:59:59.000Z
In this Letter, we study the observed distributions of rotational velocity in a sample of more than 16,000 nearby F and G dwarf stars, magnitude complete, and presenting high-precision Vsin i measurements. We show that the velocity distributions cannot be fitted by a Maxwellian. In addition, an analysis based on both Tsallis and Kaniadakis power-law statistics is by far the most appropriate statistics and gives a very good fit. It is also shown that single and binary stars have similar rotational distributions. This is the first time, to our knowledge, that these two new statistics have been tested for the rotation of such a large sample of stars, pointing solidly to a solution of the puzzling problem of the function governing the distribution of stellar rotational velocity.
The pure rotational spectrum of NaC in its X 4 state: Observation
Ziurys, Lucy M.
and the possible use of these compounds as high en- ergy density fuels.5 An increasing amount of information on metal carbides is now available from electronic spectro- scopy515 and more recently, from rotational
A reconfigurable electrode array for use in rotational electrical impedance myography
Scharfstein, Michael
2007-01-01T23:59:59.000Z
This thesis describes the design of a novel handheld electrode probe and measurement system for use in rotational electrical impedance myography (EIM), which is a method for diagnosing neuromuscular disease. The probe can ...
Measurements of the Solid-body Rotation of Anisotropic Particles in 3D Turbulence
Marcus, Guy G; Kramel, Stefan; Ni, Rui; Voth, Greg A
2014-01-01T23:59:59.000Z
We introduce a new method to measure Lagrangian vorticity and the rotational dynamics of anisotropic particles in a turbulent fluid flow. We use 3D printing technology to fabricate crosses (two perpendicular rods) and jacks (three mutually perpendicular rods). Time-resolved measurements of their orientation and solid-body rotation rate are obtained from stereoscopic video images of their motion in a turbulent flow between oscillating grids with $R_\\lambda$=$91$. The advected particles have a largest dimension of 6 times the Kolmogorov length, making them a good approximation to anisotropic tracer particles. Crosses rotate like disks and jacks rotate like spheres, so these measurements, combined with previous measurements of tracer rods, allow experimental study of ellipsoids across the full range of aspect ratios. The measured mean square tumbling rate, $\\langle \\dot{p}_i \\dot{p}_i \\rangle$, confirms previous direct numerical simulations that indicate that disks tumble much more rapidly than rods. Measurement...
Gu, Yan [Ames Laboratory
2013-05-15T23:59:59.000Z
While conventional Single Particle Tracking (SPT) techniques acquire 2D or 3D trajectories of particle probes, we have developed Single Particle Orientation and Rotational Tracking (SPORT) techniques to extract orientation and rotational information. Combined with DIC microscopy, the SPORT technique has been applied in biophysical studies, including membrane diffusion and intracellular transport. The rotational dynamics of nanoparticle vectors on live cell membranes was recorded and its influence on the fate of these nanoparticle vectors was elucidated. The rotational motions of gold nanorods with various surface modifiers were tracked continuously at a temporal resolution of 5 ms under a DIC microscope. We found that the rotational behaviors of gold nanorod vectors are strongly related to their surface charge, specific surface functional groups, and the availability of receptors on cell membranes. The study of rotational Brownian motion of nanoparticles on cell membranes will lead to a better understanding of the mechanisms of drug delivery and provide guidance in designing surface modification strategies for drug delivery vectors under various circumstances. To characterize the rotation mode of surface functionalized gold nanorods on cell membranes, the SPORT technique is combined with the correlation analysis of the bright and dark DIC intensities. The unique capabilities of visualizing and understanding rotational motions of functionalized nanoparticles on live cell membranes allow us to correlate rotational and translational dynamics in unprecedented detail and provide new insights for complex membrane processes, including electrostatic interactions, ligand-receptor binding, and lateral (confined and hopping) diffusion of membrane receptors. Surface-functionalized nanoparticles interact with the membrane in fundamentally different ways and exhibit distinct rotational modes. The early events of particle-membrane approach and attachment are directly visualized for the first time. The rotational dynamics of cargos in both active directional transport and pausing stages of axonal transport was also visualized using high-speed SPORT with a temporal resolution of 2 ms. Both long and short pauses are imaged, and the correlations between the pause duration, the rotational behaviour of the cargo at the pause, and the moving direction after the pause are established. Furthermore, the rotational dynamics leading to switching tracks are visualized in detail. These first-time observations of cargo's rotational dynamics provide new insights on how kinesin and dynein motors take the cargo through the alternating stages of active directional transport and pause. To improve the localization precision of the SPT technique with DIC microscopy, a precise three-dimensional (3D) localization method of spherical gold nanoparticle probes using model-based correlation coefficient mapping was introduced. To accomplish this, a stack of sample images at different z-positions are acquired, and a 3D intensity profile of the probe serving as the model is used to map out the positions of nanoparticles in the sample. By using this model-based correlation imaging method, precise localization can be achieved in imaging techniques with complicated point spread functions (PSF) such as differential interference contrast (DIC) microscopy. The 3D superlocalization method was applied to tracking gold nanospheres during live endocytosis events. Finally, a novel dual-modality imaging technique has been developed to super-localize a single gold nanorod while providing its orientation and rotational information. The super-localization of the gold nanorod can be accomplished by curve fitting the modified bright-field images generated by one of the two beams laterally shifted by the first Nomarski prism in a DIC microscope. The orientation and rotational information is derived from the DIC images of gold nanorods. The new imaging setup has been applied to study the steric hindrance induced by relatively large cargos in the microtubule gliding assay and to track
Spin-rotation contribution to the relaxation time of the fluorine nuclei in benzotrifluoride
Faulk, Robert Hardy
1965-01-01T23:59:59.000Z
SPIN-ROTATION CONTRIBUTION TO THE RELAXATION TIME OF THE FLUORINE NUCLEI IN BENZOTRIFLUORIDE A Thesis By ROBERT HARDY FAULK Submitted to the Graduate College of the Texas ASM University in partial fulfillment of the requirements... Contributions to the Relaxation Time for the Fluorine 6 Hydrogen Relaxation Time and the Correlation Time 33 35 36 I. INTRODUCTION The spin-rotation interaction may be visualized in the following manner. Because of the inhomogeneous distribution of charge...
Investigating Cell Adhesion via Parallel Disk Rotational Flow: A Biocompatibility Study
Rocha, Aracely
2011-08-08T23:59:59.000Z
INVESTIGATING CELL ADHESION VIA PARALLEL DISK ROTATIONAL FLOW: A BIOCOMPATIBILITY STUDY A Thesis by ARACELY ROCHA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 2008 Major Subject: Mechanical Engineering INVESTIGATING CELL ADHESION VIA PARALLEL DISK ROTATIONAL FLOW: A BIOCOMPATIBILITY STUDY A Thesis by ARACELY ROCHA Submitted to the Office...
Main effects of the Earth's rotation on the stationary states of ultra-cold neutrons
Mayeul Arminjon
2007-11-13T23:59:59.000Z
The relativistic corrections in the Hamiltonian for a particle in a uniformly rotating frame are discussed. They are shown to be negligible in the case of ultra-cold neutrons (UCN) in the Earth's gravity. The effect, on the energy levels of UCN, of the main term due to the Earth's rotation, i.e. the angular-momentum term, is calculated. The energy shift is found proportional to the energy level itself.
Apparatus and method for generating a magnetic field by rotation of a charge holding object
Gerald, II, Rex E. (Brookfield, IL); Vukovic, Lela (Westchester, IL); Rathke, Jerome W. (Homer Glenn, IL)
2009-10-13T23:59:59.000Z
A device and a method for the production of a magnetic field using a Charge Holding Object that is mechanically rotated. In a preferred embodiment, a Charge Holding Object surrounding a sample rotates and subjects the sample to one or more magnetic fields. The one or more magnetic fields are used by NMR Electronics connected to an NMR Conductor positioned within the Charge Holding Object to perform NMR analysis of the sample.
A mathematical model for the electrodeposition of amorphous alloys on a rotating disk electrode
Chen, Shiuan
1986-01-01T23:59:59.000Z
A MATHEMATICAL MODEL FOR THE ELECTRODEPOSITION OF AMORPHOUS ALLOYS ON A ROTATING DISK ELECTRODE A Thesis by SHIUAN CHEN Submitted to the Graduate College of Texas AAcM University in partial fulfillment of the requirement, for the degree... of MASTER OF SCIENCE December 19B6 Major Subject: Chemical Engineering A MATHEMATICAL MODEL FOR THE ELECTRODEPOSITION OF AMORPHOUS ALLOYS ON A ROTATING DISK ELECTRODE A Thesis by SHIUAN CHEN Approved as to style and content by: alph E. White...
Factors affecting weaning weights of calves produced in Hereford and rotational crossbred herds
Tovar-Rodriguez, Jorge
1965-01-01T23:59:59.000Z
FACTORS AFFECTING WEANING WEIGHTS OF CALVES PRODUCED IN HEREFORD AND ROTATIONAL CROSSBRED HERDS A Thesis By jORGE TOVAR R. Submitted to the Graduate College of the Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1965 Major Subject: Animal Production FACTORS AFFECTING WEANING WEIGHTS OF CALVES PRODUCED IN HEREFORD AND ROTATIONAL CROSSBRED HERDS A Thesis By JORGE TOVAR R. Approved as to style an content by: ( ' an of Committee...
The effective geometry of the $n=1$ uniformly rotating self-gravitating polytrope
Donato Bini; Christian Cherubini; Simonetta Filippi; Andrea Geralico
2014-08-20T23:59:59.000Z
The \\lq\\lq effective geometry" formalism is used to study the perturbations of a perfect barotropic Newtonian self-gravitating rotating and compressible fluid coupled with gravitational backreaction. The case of a uniformly rotating polytrope with index $n=1$ is investigated, due to its analytical tractability. Special attention is devoted to the geometrical properties of the underlying background acoustic metric, focusing in particular on null geodesics as well as on the analog light cone structure.
A mathematical model of corrosion of a conducting porous layer on a rotating disk electrode
Ryan, William Edward
1986-01-01T23:59:59.000Z
of MASTER OF SCIENCE December I 986 Major Subject: Chemical Engineering A MATHEMATICAI MODEL OF CORROSION OF A CONDUCTING POROUS LAYER. ON A ROTATING DISK ELECTRODE A Thesis bv WILLIAM EDWARD RYAN Approved as to style and content by: R. E. White... (Chairman of Committee) Charle J. Glover (Member) A. T. Watson (Member) 1 Richard H. Griffin (Member) . D. Holla, nd (Head of Department) December 1986 ABSTRACT A Mathematical Model of Corrosion of a Conduct, ing Porous Layer on a Rotating Disk...
Riggs, James Willborn
1958-01-01T23:59:59.000Z
as to style and content by: ^0tfairman of Committee^ Hoad ft Department May 1958 ACKNOWLEDGEMENTS The author wishes to acknowledge the assistance of Dr. J. B. Coon who suggested the problem and was always available for consultation. Without his knowledge... ROTATIONAL STRUCTURE...................... 71 Geometry of the Ground State of the Sulfur Dioxide Molecule .............. .71 Formulas for the Determination of the Wave Numbers of a Vibronic and a Rotational B a n d ...................... 72...
A numerical method for the design and analysis of counter-rotating propellers
Playle, Scott Charles
1984-01-01T23:59:59.000Z
-Rotating Propellers from Airfoil Characteristics", NACA ARR 3EZ4 (WR L-330), May 1943. 13. Davidson, R. E. , "Optimization and Performance Calculation of Dual-Rotation Propellers", NASA TP 1948, December 1981. 14. Theodorsen, T. , "The Theory of Propellers... 1. Design Flight Conditions 2. Propeller Performance from Naiman and Davidson Design Methods 3. Efficiency Characteristics of the Three Propeller Designs 4. Thrust Coefficients of the Three Propeller Designs 5. Power Coefficients of the Three...
Neutrino transport and hydrodynamic stability of rotating proto-neutron stars
V. Urpin
2007-04-24T23:59:59.000Z
We consider stability of differentially rotating non-magnetic proto-neutron stars. When neutrino transport is efficient, the star can be subject to a diffusive instability that can occur even in the convectively stable region. The instability arises on the time-scale comparable to the time-scale of thermal diffusion. Hydrodynamic motions driven by the instability can lead to anisotropy in the neutrino flux since the instability is suppressed near the equator and rotation axis.
Thermal Effects of Rotation in Random Classical Zero-Point Radiation
Yefim S. Levin
2007-04-27T23:59:59.000Z
The rotating reference system, two-point correlation functions, and energy density are used as the basis for investigating thermal effects observed by a detector rotating through random classical zero-point radiation. The RS consists of Frenet -Serret orthogonal tetrads where the rotating detector is at rest and has a constant acceleration vector. The CFs and the energy density at the rotating reference system should be periodic with rotation period because CF and energy density measurements is one of the tools the detector can use to justify the periodicity of its motion. The CFs have been calculated for both electromagnetic and massless scalar fields in two cases, with and without taking this periodicity into consideration. It turned out that only periodic CFs have some thermal features and particularly the Planck's factor with the temperature T= h w /k . Regarding to the energy density of both electromagnetic and massless scalar field it is shown that the detector rotating in the zero-point radiation observes not only this original zero-point radiation but, above that, also the radiation which would have been observed by an inertial detector in the thermal bath with the Plank's spectrum at the temperature T. This effect is masked by factor 2/3(4 gamma^2-1) for the electromagnetic field and 2/9 (4 gamma ^2-1) for the massless scalar field, where the Lorentz factor gamma=(1 - v^2 / c^2)^(1/2). Appearance of these masking factors is connected with the fact that rotation is defined by two parameters, angular velocity w and the radius of rotation, in contrast with a uniformly accelerated linear motion which is defined by only one parameter, acceleration a. Our calculations involve classical point of view only and to the best of our knowledge these results have not been reported in quantum theory yet.
On Rotating and Oscillating Four-Spin Strings in AdS5 X S5
Kamal L. Panigrahi; Pabitra M. Pradhan
2012-10-26T23:59:59.000Z
We study rigidly rotating strings in AdS5 X S5 background with one spin along AdS5 and three angular momenta along S5. We find dispersion relations among various charges and interpret them as giant magnon and spiky string solutions in various limits. Further we present an example of oscillating string which oscillates in the radial direction of the AdS5 and at the same time rotates in S5.
On Rotating and Oscillating Four-Spin Strings in AdS5 X S5
Panigrahi, Kamal L
2012-01-01T23:59:59.000Z
We study rigidly rotating strings in AdS5 X S5 background with one spin along AdS5 and three angular momenta along S5. We find dispersion relations among various charges and interpret them as giant magnon and spiky string solutions in various limits. Further we present an example of oscillating string which oscillates in the radial direction of the AdS5 and at the same time rotates in S5.