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Sample records for phase rotator system

  1. Induction accelerators for the phase rotator system

    SciTech Connect

    Reginato, Lou; Yu, Simon; Vanecek, Dave

    2001-07-30

    The principle of magnetic induction has been applied to the acceleration of high current beams in betatrons and a variety of induction accelerators. The linear induction accelerator (LIA) consists of a simple nonresonant structure where the drive voltage is applied to an axially symmetric gap that encloses a toroidal ferromagnetic material. The change in flux in the magnetic core induces an axial electric field that provides particle acceleration. This simple nonresonant (low Q) structure acts as a single turn transformer that can accelerate from hundreds of amperes to tens of kiloamperes, basically only limited by the drive impedance. The LIA is typically a low gradient structure that can provide acceleration fields of varying shapes and time durations from tens of nanoseconds to several microseconds. The efficiency of the LIA depends on the beam current and can exceed 50% if the beam current exceeds the magnetization current required by the ferromagnetic material. The acceleration voltage available is simply given by the expression V=A dB/dt. Hence, for a given cross section of material, the beam pulse duration influences the energy gain. Furthermore, a premium is put on minimizing the diameter, which impacts the total weight or cost of the magnetic material. The diameter doubly impacts the cost of the LIA since the power (cost) to drive the cores is proportional to the volume as well. The waveform requirements during the beam pulse makes it necessary to make provisions in the pulsing system to maintain the desired dB/dt during the useful part of the acceleration cycle. This is typically done two ways, by using the final stage of the pulse forming network (PFN) and by the pulse compensation network usually in close proximity of the acceleration cell. The choice of magnetic materials will be made by testing various materials both ferromagnetic and ferrimagnetic. These materials will include the nickel-iron, silicon steel amorphous and various types of ferrites not

  2. Transient stability enhancement of electric power generating systems by 120-degree phase rotation

    DOEpatents

    Cresap, Richard L.; Taylor, Carson W.; Kreipe, Michael J.

    1982-01-01

    A method and system for enhancing the transient stability of an intertied three-phase electric power generating system. A set of power exporting generators (10) is connected to a set of power importing generators (20). When a transient cannot be controlled by conventional stability controls, and imminent loss of synchronism is detected (such as when the equivalent rotor angle difference between the two generator sets exceeds a predetermined value, such as 150 degrees), the intertie is disconnected by circuit breakers. Then a switch (30) having a 120-degree phase rotation, or a circuit breaker having a 120-degree phase rotation is placed in the intertie. The intertie is then reconnected. This results in a 120-degree reduction in the equivalent rotor angle difference between the two generator sets, making the system more stable and allowing more time for the conventional controls to stabilize the transient.

  3. Unidirectional rotating coordinate rotation digital computer algorithm based on rotational phase estimation.

    PubMed

    Zhang, Chaozhu; Han, Jinan; Yan, Huizhi

    2015-06-01

    The improved coordinate rotation digital computer (CORDIC) algorithm gives high precision and resolution phase rotation, but it has some shortages such as high iterations and big system delay. This paper puts forward unidirectional rotating CORDIC algorithm to solve these problems. First, using under-damping theory, a part of unidirectional phase rotations is carried out. Then, the threshold value of angle is determined based on phase rotation estimation method. Finally, rotation phase estimation completes the rest angle iterations. Furthermore, the paper simulates and implements the numerical control oscillator by Quartus II software and Modelsim software. According to the experimental results, the algorithm reduces iterations and judgment of sign bit, so that it decreases system delay and resource utilization and improves the throughput. We always analyze the error brought by this algorithm. It turned out that the algorithm has a good application prospect in global navigation satellite system and channelized receiver. PMID:26133856

  4. Multiplexing in optical encryption by using an aperture system and a rotating sandwich random phase diffuser in the Fourier plane

    NASA Astrophysics Data System (ADS)

    Singh, Madan; Kumar, Arvind; Singh, Kehar

    2008-03-01

    In the present paper, we describe multiplexing in optical encryption of two-dimensional images, by using apertures and rotation of one of the constituent phase diffusers of a sandwich phase diffuser in the Fourier plane. The sandwich phase diffuser is made with two random constituent phase-diffusing surfaces sandwiched together. The apertures of different sizes and shapes are made with the help of 'paint brush' software. Simulation results are presented showing the effects of size, shape, and orientation of the apertures on the decrypted images obtained via multiplexing techniques. In addition to the results of using aperture systems in encryption and decryption, the results of rotation of one of the constituent phase diffusers in decryption are analyzed and used in multiplexing. Due to the use of aperture systems and the rotation of the constituent phase diffuser, the multiplexing capability of the system in encryption is enhanced along with the enhanced security due to using a sandwich diffuser. To evaluate the reliability of the technique, mean square error between the decrypted and the original image has been calculated.

  5. Intercarrier interference reduction in MC-CDMA system through second order duobinary coded phase rotated conjugate cancellation scheme.

    PubMed

    Chitra, S; Kumaratharan, N

    2015-01-01

    Multi-carrier code division multiple access (MC-CDMA) technique is one of the strong candidates for next generation wireless mobile communication systems. Multi-carrier systems are very much sensitive to carrier frequency offset (CFO) results in intercarrier interference (ICI). To mitigate ICI without any spectral loss, a second order duobinary coded phase rotated conjugate cancellation algorithm is proposed in this paper. In the conventional phase rotated conjugate cancellation (PRCC) technique, one path carries the MC-CDMA signal with a phase spin of ϕ and the other path carries the conjugate of the first path signal with -ϕ phase spin. This artificial phase rotation allows the transmitter to tune the transmitted signals so that the ICI effects could be mutually cancelled at the receiver. Although the PRCC technique reduces the spectral efficiency, the limitation can be overcome by the joint second order duobinary coding scheme with PRCC technique. In the proposed method, the correlative coding between the binary symbols modulated on adjacent subcarriers is used to reduce the ICI without any spectral loss. Simulation results show that the proposed PRCC method provides better carrier to interference ratio (CIR) and bit error rate (BER) performances compared to the conventional conjugate cancellation (CC) technique.

  6. Intercarrier Interference Reduction in MC-CDMA System through Second Order Duobinary Coded Phase Rotated Conjugate Cancellation Scheme

    PubMed Central

    Chitra, S.; Kumaratharan, N.

    2015-01-01

    Multi-carrier code division multiple access (MC-CDMA) technique is one of the strong candidates for next generation wireless mobile communication systems. Multi-carrier systems are very much sensitive to carrier frequency offset (CFO) results in intercarrier interference (ICI). To mitigate ICI without any spectral loss, a second order duobinary coded phase rotated conjugate cancellation algorithm is proposed in this paper. In the conventional phase rotated conjugate cancellation (PRCC) technique, one path carries the MC-CDMA signal with a phase spin of ϕ and the other path carries the conjugate of the first path signal with -ϕ phase spin. This artificial phase rotation allows the transmitter to tune the transmitted signals so that the ICI effects could be mutually cancelled at the receiver. Although the PRCC technique reduces the spectral efficiency, the limitation can be overcome by the joint second order duobinary coding scheme with PRCC technique. In the proposed method, the correlative coding between the binary symbols modulated on adjacent subcarriers is used to reduce the ICI without any spectral loss. Simulation results show that the proposed PRCC method provides better carrier to interference ratio (CIR) and bit error rate (BER) performances compared to the conventional conjugate cancellation (CC) technique. PMID:25790029

  7. Does the Berry phase in a quantum optical system originate from the rotating wave approximation?

    NASA Astrophysics Data System (ADS)

    Wang, Minghao; Wei, L. F.; Liang, J. Q.

    2015-06-01

    The Berry phase (BP) in a quantized light field demonstrated more than a decade ago (Fuentes-Guridi et al., 2002 [9]) has attracted considerable attention, since it plays an important role in the cavity quantum electrodynamics. However, it is argued in Larson (2012) [15] that such a BP is just due to the rotating wave approximation (RWA) and the relevant BP should vanish beyond this approximation. Based on a consistent analysis we conclude in this letter that the BP in a generic Rabi model actually exists, no matter whether the RWA is applied. The existence of BP is also generalized to a three-level atom in the quantized cavity field.

  8. Rotating shielded crane system

    DOEpatents

    Commander, John C.

    1988-01-01

    A rotating, radiation shielded crane system for use in a high radiation test cell, comprises a radiation shielding wall, a cylindrical ceiling made of radiation shielding material and a rotatable crane disposed above the ceiling. The ceiling rests on an annular ledge intergrally attached to the inner surface of the shielding wall. Removable plugs in the ceiling provide access for the crane from the top of the ceiling into the test cell. A seal is provided at the interface between the inner surface of the shielding wall and the ceiling.

  9. Rotating Aperture System

    DOEpatents

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

    2005-01-18

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

  10. Phase Modulation Stops Levitated Sample Rotation

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Brown, J. H.

    1984-01-01

    Rotation of sample in acoustic levitator prevented by relatively simple phase-modulation scheme. Technique differs from older methods; no feedback control or observation of sample required, nor necessary to carefully tune or detune two oscillators to precise frequency differences from resonance.

  11. Rotational Rehybridization and the High Temperature Phase of UC2

    SciTech Connect

    Wen, Xiaodong; Rudin, Sven P.; Batista, Enrique R.; Clark, David L.; Scuseria, Gustavo E.; Martin, Richard L.

    2012-12-03

    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).

  12. Machine protection system for rotating equipment and method

    DOEpatents

    Lakshminarasimha, Arkalgud N.; Rucigay, Richard J.; Ozgur, Dincer

    2003-01-01

    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.

  13. Rotating Cylinder Treatment System Demonstration

    EPA Science Inventory

    In August 2008, a rotating cylinder treatment system (RCTSTM) demonstration was conducted near Gladstone, CO. The RCTSTM is a novel technology developed to replace the aeration/oxidation and mixing components of a conventional lime precipitation treatment s...

  14. Faraday rotation system. Topical report

    SciTech Connect

    Bauman, L.E.; Wang, W.

    1994-07-01

    The Faraday Rotation System (FRS) is one of the advanced laser-based diagnostics developed at DIAL to provide support for the demonstration of prototype-scale coal-fired combustion magnetohydrodynamic (MHD) electrical power generation. Intended for application in the MHD channel, the system directly measures electron density through a measurement of the induced rotation in the polarization of a far infrared laser beam after passing through the MHD flow along the magnetic field lines. A measurement of the induced polarization ellipticity provides a measure of the electron collision frequency which together with the electron density gives the electron conductivity, a crucial parameter for MHD channel performance. The theory of the measurements, a description of the system, its capabilities, laboratory demonstration measurements on seeded flames with comparison to emission absorption measurements, and the current status of the system are presented in this final report.

  15. Geometric phases in discrete dynamical systems

    NASA Astrophysics Data System (ADS)

    Cartwright, Julyan H. E.; Piro, Nicolas; Piro, Oreste; Tuval, Idan

    2016-10-01

    In order to study the behaviour of discrete dynamical systems under adiabatic cyclic variations of their parameters, we consider discrete versions of adiabatically-rotated rotators. Parallelling the studies in continuous systems, we generalize the concept of geometric phase to discrete dynamics and investigate its presence in these rotators. For the rotated sine circle map, we demonstrate an analytical relationship between the geometric phase and the rotation number of the system. For the discrete version of the rotated rotator considered by Berry, the rotated standard map, we further explore this connection as well as the role of the geometric phase at the onset of chaos. Further into the chaotic regime, we show that the geometric phase is also related to the diffusive behaviour of the dynamical variables and the Lyapunov exponent.

  16. Rotational Electromagnetic Energy Harvesting System

    NASA Astrophysics Data System (ADS)

    Dinulovic, Dragan; Brooks, Michael; Haug, Martin; Petrovic, Tomislav

    This paper presents development of the rotational electromagnetic energy harvesting transducer. The transducer is driven mechanically by pushing a button; therefore, the mechanical energy will be converted into electrical energy. The energy harvesting (EH) transducer consists of multilayer planar coils embedded in a PCB, multipolar NdFeB hard magnets, and a mechanical system for movement conversion. The EH transducer generate an energy of about 4 mJ at a load of 10 Ω. The maximum open circuit output voltage is as high as 2 V and the maximum short circuit output current is 800 mA.

  17. Characterization of a generalized elliptical phase retarder by using equivalent theorem of a linear phase retarder and a polarization rotator

    NASA Astrophysics Data System (ADS)

    Yu, Chih-Jen; Chou, Chien

    2011-03-01

    An equivalence theory based on a unitary optical system of a generalized elliptical phase retarder was derived. Whereas the elliptical phase retarder can be treated as the combination of a linear phase retarder and a polarization rotator equivalently. Three fundamental parameters, including the elliptical phase retardation, the azimuth angle and the ellipticity angle of the fast elliptical eigen-polarization state were derived. All parameters of a generalized elliptical phase retarder can be determined from the analytical solution of the characteristic parameters of the optical components: linear phase retardation and fast axis angle of the equivalently linear phase retarder respectively, and polarization rotation angle of an equivalent polarization rotator. In this study, the experimental verification was demonstrated by testing a twisted nematic liquid crystal device (TNLCD) treated as a generalized elliptical phase retarder. A dual-frequency heterodyne ellipsometer was setup and the experimental result demonstrates the capability of the equivalent theory on elliptical birefringence measurement at high sensitivity by using heterodyne technique.

  18. Quantum Rotational Effects in Nanomagnetic Systems

    NASA Astrophysics Data System (ADS)

    O'Keeffe, Michael F.

    Quantum tunneling of the magnetic moment in a nanomagnet must conserve the total angular momentum. For a nanomagnet embedded in a rigid body, reversal of the magnetic moment will cause the body to rotate as a whole. When embedded in an elastic environment, tunneling of the magnetic moment will cause local elastic twists of the crystal structure. In this thesis, I will present a theoretical study of the interplay between magnetization and rotations in a variety of nanomagnetic systems which have some degree of rotational freedom. We investigate the effect of rotational freedom on the tunnel splitting of a nanomagnet which is free to rotate about its easy axis. Calculating the exact instanton of the coupled equations of motion shows that mechanical freedom of the particle renormalizes the easy axis anisotropy, increasing the tunnel splitting. To understand magnetization dynamics in free particles, we study a quantum mechanical model of a tunneling spin embedded in a rigid rotor. The exact energy levels for a symmetric rotor exhibit first and second order quantum phase transitions between states with different values the magnetic moment. A quantum phase diagram is obtained in which the magnetic moment depends strongly on the moments of inertia. An intrinsic contribution to decoherence of current oscillations of a flux qubit must come from the angular momentum it transfers to the surrounding body. Within exactly solvable models of a qubit embedded in a rigid body and an elastic medium, we show that slow decoherence is permitted if the solid is macroscopically large. The spin-boson model is one of the simplest representations of a two-level system interacting with a quantum harmonic oscillator, yet has eluded a closed-form solution. I investigate some possible approaches to understanding its spectrum. The Landau-Zener dynamics of a tunneling spin coupled to a torsional resonator show that for certain parameter ranges the system exhibits multiple Landau-Zener transitions

  19. Phase transitions for rotational states within an algebraic cluster model

    NASA Astrophysics Data System (ADS)

    López Moreno, E.; Morales Hernández, G. E.; Hess, P. O.; Yépez Martínez, H.

    2016-07-01

    The ground state and excited, rotational phase transitions are investigated within the Semimicroscopic Algebraic Cluster Model (SACM). The catastrophe theory is used to describe these phase transitions. Short introductions to the SACM and the catastrophe theory are given. We apply the formalism to the case of 16O+α→20Ne.

  20. Cooling system for rotating machine

    DOEpatents

    Gerstler, William Dwight; El-Refaie, Ayman Mohamed Fawzi; Lokhandwalla, Murtuza; Alexander, James Pellegrino; Quirion, Owen Scott; Palafox, Pepe; Shen, Xiaochun; Salasoo, Lembit

    2011-08-09

    An electrical machine comprising a rotor is presented. The electrical machine includes the rotor disposed on a rotatable shaft and defining a plurality of radial protrusions extending from the shaft up to a periphery of the rotor. The radial protrusions having cavities define a fluid path. A stationary shaft is disposed concentrically within the rotatable shaft wherein an annular space is formed between the stationary and rotatable shaft. A plurality of magnetic segments is disposed on the radial protrusions and the fluid path from within the stationary shaft into the annular space and extending through the cavities within the radial protrusions.

  1. Particle Rotation Effects in Rarefied Two-Phase Plume Flows

    NASA Astrophysics Data System (ADS)

    Burt, Jonathan M.; Boyd, Iain D.

    2005-05-01

    We evaluate the effects of solid particle rotation in high-altitude solid rocket exhaust plume flows, through the development and application of methods for the simulation of two phase flows involving small rotating particles and a nonequilibrium gas. Green's functions are derived for the force, moment, and heat transfer rate to a rotating solid sphere within a locally free-molecular gas, and integration over a Maxwellian gas velocity distribution is used to determine the influence of particle rotation on the heat transfer rate at the equilibrium limit. The use of these Green's functions for the determination of particle phase properties through the Direct Simulation Monte Carlo method is discussed, and a procedure is outlined for the stochastic modeling of interphase collisions. As a test case, we consider the nearfield plume flow for a Star-27 solid rocket motor exhausting into a vacuum, and vary particle angular velocities at the nozzle exit plane in order to evaluate the influence of particle rotation on various flow properties. Simulation results show that rotation may lead to slightly higher particle temperatures near the central axis, but for the case considered the effects of particle rotation are generally found to be negligible.

  2. Determination of the liquid crystals phase transition temperatures using optical rotation effect

    NASA Astrophysics Data System (ADS)

    Niu, Xiao-ling; Liu, Wei-guo; Liu, Peng; Cai, Chang-long

    2011-11-01

    Using optical rotation effect, a sensitive, simple optical analytical system is developed for determining the phase transition temperatures of liquid crystals (LCs). When a monochromatic polarized light passes through LCs sample and analyzer, the light intensity changes with temperature. Especially, during the phase transition process, the intensity varies greatly due to optical rotation effect. The variation of light intensity versus variation of temperature curve shows the phase transition temperatures of LCs clearly. The phase transition temperatures of three cholesteric liquid crystals (ChLCs) and a nematic liquid crystals (NLCs) were detected by this method, and compared with those of the differential scanning calorimetry (DSC) and polarized light microscope (PLM) methods.

  3. Boundary layer control of rotating convection systems.

    PubMed

    King, Eric M; Stellmach, Stephan; Noir, Jerome; Hansen, Ulrich; Aurnou, Jonathan M

    2009-01-15

    Turbulent rotating convection controls many observed features of stars and planets, such as magnetic fields, atmospheric jets and emitted heat flux patterns. It has long been argued that the influence of rotation on turbulent convection dynamics is governed by the ratio of the relevant global-scale forces: the Coriolis force and the buoyancy force. Here, however, we present results from laboratory and numerical experiments which exhibit transitions between rotationally dominated and non-rotating behaviour that are not determined by this global force balance. Instead, the transition is controlled by the relative thicknesses of the thermal (non-rotating) and Ekman (rotating) boundary layers. We formulate a predictive description of the transition between the two regimes on the basis of the competition between these two boundary layers. This transition scaling theory unifies the disparate results of an extensive array of previous experiments, and is broadly applicable to natural convection systems.

  4. Boundary layer control of rotating convection systems.

    PubMed

    King, Eric M; Stellmach, Stephan; Noir, Jerome; Hansen, Ulrich; Aurnou, Jonathan M

    2009-01-15

    Turbulent rotating convection controls many observed features of stars and planets, such as magnetic fields, atmospheric jets and emitted heat flux patterns. It has long been argued that the influence of rotation on turbulent convection dynamics is governed by the ratio of the relevant global-scale forces: the Coriolis force and the buoyancy force. Here, however, we present results from laboratory and numerical experiments which exhibit transitions between rotationally dominated and non-rotating behaviour that are not determined by this global force balance. Instead, the transition is controlled by the relative thicknesses of the thermal (non-rotating) and Ekman (rotating) boundary layers. We formulate a predictive description of the transition between the two regimes on the basis of the competition between these two boundary layers. This transition scaling theory unifies the disparate results of an extensive array of previous experiments, and is broadly applicable to natural convection systems. PMID:19148097

  5. Meniscus Stability in Rotating Systems

    NASA Astrophysics Data System (ADS)

    Reichel, Yvonne; Dreyer, Michael

    2013-11-01

    In this study, the stability of free surfaces of fluid between two rotating coaxial, circular disks is examined. Radially mounted baffles are used to form menisci of equal size. To the center of the upper disk, a tube is connected in which a separate meniscus is formed. Assuming solid-body rotation and ignoring dynamic effects, it is observed that the free surfaces between the disks fail to remain stable once the rotation speed exceeds a critical value. In other words, Rayleigh-Taylor instability ensues when the capillary forces fail to balance centrifugal forces. Dimensionless critical rotation speeds are studied by means of the Surface Evolver via SE-FIT for varied number of baffles, the normalized distance between the disks, and the normalized central tube radius. Drop tower tests are performed to confirm some of the numerical results. The computation also reveals that there are different modes of instability as a function of the relevant parameters. This study was funded by the space agency of the German Aerospace Center with resources of the Federal Ministry of Economics and Technology on the basis of a resolution of the German Bundestag under grant number 50 RL 1320.

  6. Quantum phases of vortices in rotating Bose-Einstein condensates.

    PubMed

    Cooper, N R; Wilkin, N K; Gunn, J M

    2001-09-17

    We investigate the ground states of weakly interacting bosons in a rotating trap as a function of the number of bosons, N, and the average number of vortices, N(V). We identify the filling fraction nu identical with N/N(V) as the parameter controlling the nature of these states. We present results indicating that, as a function of nu, there is a zero temperature phase transition between a triangular vortex lattice phase, and strongly correlated vortex liquid phases. The vortex liquid phases appear to be the Read-Rezayi parafermion states. PMID:11580492

  7. System for controlled acoustic rotation of objects

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B. (Inventor)

    1983-01-01

    A system is described for use with acoustically levitated objects, which enables close control of rotation of the object. One system includes transducers that propagate acoustic waves along the three dimensions (X, Y, Z) of a chamber of rectangular cross section. Each transducers generates one wave which is resonant to a corresponding chamber dimension to acoustically levitate an object, and additional higher frequency resonant wavelengths for controlling rotation of the object. The three chamber dimensions and the corresponding three levitation modes (resonant wavelengths) are all different, to avoid degeneracy, or interference, of waves with one another, that could have an effect on object rotation. Only the higher frequencies, with pairs of them having the same wavelength, are utilized to control rotation, so that rotation is controlled independently of levitation and about any arbitrarily chosen axis.

  8. System for controlled acoustic rotation of objects

    NASA Astrophysics Data System (ADS)

    Barmatz, M. B.

    1983-07-01

    A system is described for use with acoustically levitated objects, which enables close control of rotation of the object. One system includes transducers that propagate acoustic waves along the three dimensions (X, Y, Z) of a chamber of rectangular cross section. Each transducers generates one wave which is resonant to a corresponding chamber dimension to acoustically levitate an object, and additional higher frequency resonant wavelengths for controlling rotation of the object. The three chamber dimensions and the corresponding three levitation modes (resonant wavelengths) are all different, to avoid degeneracy, or interference, of waves with one another, that could have an effect on object rotation. Only the higher frequencies, with pairs of them having the same wavelength, are utilized to control rotation, so that rotation is controlled independently of levitation and about any arbitrarily chosen axis.

  9. On-line phase measuring profilometry for a rotating object

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Cao, Yiping; Yang, Xin; Peng, Kuang

    2014-11-01

    On-line phase measuring profilometry (OPMP) for a rotating object is proposed. N frames of circular sinusoidal grating patterns are designed in advance, in which the transmittance along the radial direction is sinusoidal and there is a fixed shifting phase pitch of 2π/N between every adjacent two grating patterns along the radial direction. While the measured object is rotating, the designed grating patterns are projected onto the rotating object by digital light processing and the corresponding deformed patterns caused by the object at different positions are captured by a charge coupled device camera. By pixel matching and rotation transformation with special marks, N frames of the deformed patterns of the object at the same position can be extracted. Hence, the rotating object can be reconstructed by the extracted deformed patterns. The results of computer emulation and experiment show the feasibility and validity of the proposed OPMP. Either the maximum measurement absolute error is 0.118 mm or the maximum root mean square error is 0.077 mm in the measured region of 0 to 25 mm.

  10. Measurement of Phase Difference for Micromachined Gyros Driven by Rotating Aircraft

    PubMed Central

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-01-01

    This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control system, such as damping in the attitude stabilization loop, the gyro signal must be kept in sync with the control signal. Therefore, the phase difference between both signals needs to be measured accurately. Considering that phase difference is mainly produced by both the micromachined part and the signal conditioning circuit, a mathematical model has been established and analyzed to determine the gyro's phase frequency characteristics. On the basis of theoretical analysis, a dynamic simulation has been done for a case where the spin frequency is 15 Hz. Experimental results with the proposed measurement method applied to a silicon micromachined gyro driven by a rotating aircraft demonstrate that it is effective in practical applications. Measured curve and numerical analysis of phase frequency characteristic are in accordance, and the error between measurement and simulation is only 5.3%. PMID:23966195

  11. Measurement of phase difference for micromachined gyros driven by rotating aircraft.

    PubMed

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-08-21

    This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control system, such as damping in the attitude stabilization loop, the gyro signal must be kept in sync with the control signal. Therefore, the phase difference between both signals needs to be measured accurately. Considering that phase difference is mainly produced by both the micromachined part and the signal conditioning circuit, a mathematical model has been established and analyzed to determine the gyro's phase frequency characteristics. On the basis of theoretical analysis, a dynamic simulation has been done for a case where the spin frequency is 15 Hz. Experimental results with the proposed measurement method applied to a silicon micromachined gyro driven by a rotating aircraft demonstrate that it is effective in practical applications. Measured curve and numerical analysis of phase frequency characteristic are in accordance, and the error between measurement and simulation is only 5.3%.

  12. Phase diagram of a rotating Bose-Einstein condensate with anharmonic confinement

    SciTech Connect

    Jackson, A.D.; Kavoulakis, G.M.; Lundh, E.

    2004-05-01

    We examine the phase diagram of an effectively repulsive Bose-Einstein condensate of atoms that rotates in a quadratic-plus-quartic potential. With use of a variational method we identify the three possible phases of the system as a function of the rotational frequency of the trap and of the coupling constant. The derived phase diagram is shown to be universal and partly exact in the limit of weak interactions and small anharmonicity. The variational results are found to be consistent with numerical solutions of the Gross-Pitaevskii equation.

  13. Unified matrix approach to the description of phase-space rotators.

    PubMed

    Gitin, Andrey V

    2016-03-01

    In optics, the rotation of a phase-space can be realized via light propagation through both an inhomogeneous medium with a radial gradient of refractive index and two special kinds of mirror-symmetrical optical systems suggested by Lohmann. Although light propagation through Lohmann's systems is described in terms of matrix optics, light propagation through the gradient-index medium is traditionally described as a solution of the wave equation. The difference in these descriptions hinders the understanding of the phase-space rotators. Fortunately, there is a matrix description of light propagation through a gradient-index medium too. A general description of the phase-space rotators is presented, which can be used to treat light propagation through both Lohmann's systems and the gradient-index medium in a unified matrix manner.

  14. Measurement of unsteady pressures in rotating systems

    NASA Technical Reports Server (NTRS)

    Kienappel, K.

    1978-01-01

    The principles of the experimental determination of unsteady periodic pressure distributions in rotating systems are reported. An indirect method is discussed, and the effects of the centrifugal force and the transmission behavior of the pressure measurement circuit were outlined. The required correction procedures are described and experimentally implemented in a test bench. Results show that the indirect method is suited to the measurement of unsteady nonharmonic pressure distributions in rotating systems.

  15. Boundary Layer Control of Rotating Convection Systems

    NASA Astrophysics Data System (ADS)

    King, E. M.; Stellmach, S.; Noir, J.; Hansen, U.; Aurnou, J. M.

    2008-12-01

    Rotating convection is ubiquitous in the natural universe, and is likely responsible for planetary processes such magnetic field generation. Rapidly rotating convection is typically organized by the Coriolis force into tall, thin, coherent convection columns which are aligned with the axis of rotation. This organizational effect of rotation is thought to be responsible for the strength and structure of magnetic fields generated by convecting planetary interiors. As thermal forcing is increased, the relative influence of rotation weakens, and fully three-dimensional convection can exist. It has long been assumed that rotational effects will dominate convection dynamics when the ratio of buoyancy to the Coriolis force, the convective Rossby number, Roc, is less than unity. We investigate the influence of rotation on turbulent Rayleigh-Benard convection via a suite of coupled laboratory and numerical experiments over a broad parameter range: Rayleigh number, 10310; Ekman number, 10-6≤ E ≤ ∞; and Prandtl number, 1≤ Pr ≤ 100. In particular, we measure heat transfer (as characterized by the Nusselt number, Nu) as a function of the Rayleigh number for several different Ekman and Prandtl numbers. Two distinct heat transfer scaling regimes are identified: non-rotating style heat transfer, Nu ~ Ra2/7, and quasigeostrophic style heat transfer, Nu~ Ra6/5. The transition between the non-rotating regime and the rotationally dominant regime is described as a function of the Ekman number, E. We show that the regime transition depends not on the global force balance Roc, but on the relative thicknesses of the thermal and Ekman boundary layers. The transition scaling provides a predictive criterion for the applicability of convection models to natural systems such as Earth's core.

  16. Rotating Rake Turbofan Duct Mode Measurement System

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.

    2005-01-01

    An experimental measurement system was developed and implemented by the NASA Glenn Research Center in the 1990s to measure turbofan duct acoustic modes. The system is a continuously rotating radial microphone rake that is inserted into the duct. This Rotating Rake provides a complete map of the acoustic duct modes present in a ducted fan and has been used on a variety of test articles: from a low-speed, concept test rig, to a full-scale production turbofan engine. The Rotating Rake has been critical in developing and evaluating a number of noise reduction concepts as well as providing experimental databases for verification of several aero-acoustic codes. More detailed derivation of the unique Rotating Rake equations are presented in the appendix.

  17. Excitation system for rotating synchronous machines

    DOEpatents

    Umans, Stephen D.; Driscoll, David J.

    2002-01-01

    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.

  18. Influence of rotation on BN separation in binary particle system

    NASA Astrophysics Data System (ADS)

    Wu, Ping; Wang, Shuang; Xie, Ziang; Huang, Yuming; Tong, Lige; Zhang, Peikun; Yin, Shaowu; Liu, Chuanping; Wang, Li

    2013-06-01

    Granular particles systems under vertical vibration exhibit Brazilian Nut separation (BN), Reversed BN (RBN) separation or transitional phases at different vibrating conditions. In the present work, we investigate the influence of rotation on the BN separation of a binary granular particle system by changing rotational speed. 13X molecular sieve particles with diameter 6.00 mm and 0.60 mm are used. Vibration frequency f is 30 Hz and dimensionless acceleration Γ is 1.52 or 1.75, in which the particle system mainly exhibits BN separation tendency. Rotational speed ω varies from 0 to 150rpm, while the upper surface of the particle system maintains flat. We took the pictures of the particles distribution and measured the particles mass layer by layer to obtain the 3-D distribution of the particles. The results show that rotation enhances the BN separation tendency at slow rotational speed. The BN separation becomes strongest when ω is approximately 50rpm, then the BN separation tendency reduces as ω continues to increase. A butterfly pattern appears in the middle particles layer under the simultaneous stimulations of vibration and rotation.

  19. Balanced-Rotating-Spray Tank-And-Pipe-Cleaning System

    NASA Technical Reports Server (NTRS)

    Thaxton, Eric A.; Caimi, Raoul E. B.

    1995-01-01

    Spray head translates and rotates to clean entire inner surface of tank or pipe. Cleansing effected by three laterally balanced gas/liquid jets from spray head that rotates about longitudinal axis. Uses much less liquid. Cleaning process in system relies on mechanical action of jets instead of contaminant dissolution. Eliminates very difficult machining needed to make multiple converging/diverging nozzles within one spray head. Makes nozzle much smaller. Basic two-phase-flow, supersonic-nozzle design applied to other spray systems for interior or exterior cleaning.

  20. Design and Implementation of Hybrid CORDIC Algorithm Based on Phase Rotation Estimation for NCO

    PubMed Central

    Zhang, Chaozhu; Han, Jinan; Li, Ke

    2014-01-01

    The numerical controlled oscillator has wide application in radar, digital receiver, and software radio system. Firstly, this paper introduces the traditional CORDIC algorithm. Then in order to improve computing speed and save resources, this paper proposes a kind of hybrid CORDIC algorithm based on phase rotation estimation applied in numerical controlled oscillator (NCO). Through estimating the direction of part phase rotation, the algorithm reduces part phase rotation and add-subtract unit, so that it decreases delay. Furthermore, the paper simulates and implements the numerical controlled oscillator by Quartus II software and Modelsim software. Finally, simulation results indicate that the improvement over traditional CORDIC algorithm is achieved in terms of ease of computation, resource utilization, and computing speed/delay while maintaining the precision. It is suitable for high speed and precision digital modulation and demodulation. PMID:25110750

  1. Rotating Cylinder Treatment System Demonstration (Presentation)

    EPA Science Inventory

    In August 2008, a rotating cylinder treatment system (RCTSTM) demonstration was conducted near Gladstone, CO. The RCTSTM is a novel technology developed to replace the aeration/oxidation and mixing components of a conventional lime precipitation treatment s...

  2. Theory of symmetry for a rotational relativistic Birkhoff system

    NASA Astrophysics Data System (ADS)

    Luo, Shao-Kai; Chen, Xiang-Wei; Guo, Yong-Xin

    2002-05-01

    The theory of symmetry for a rotational relativistic Birkhoff system is studied. In terms of the invariance of the rotational relativistic Pfaff-Birkhoff-D'Alembert principle under infinitesimal transformations, the Noether symmetries and conserved quantities of a rotational relativistic Birkhoff system are given. In terms of the invariance of rotational relativistic Birkhoff equations under infinitesimal transformations, the Lie symmetries and conserved quantities of the rotational relativistic Birkhoff system are given.

  3. Birkhoff's equations and geometrical theory of rotational relativistic system

    NASA Astrophysics Data System (ADS)

    Luo, Shao-kai; Chen, Xiang-wei; Fu, Jing-li

    2001-04-01

    The Birkhoffian and Birkhoff's functions of a rotational relativistic system are constructed, the Pfaff action of rotational relativistic system is defined, the Pfaff-Birkhoff principle of a rotational relativistic system is given and the Pfaff-Birkhoff-D'Alembert principles and Birkhoff's equations of rotational relativistic system are constructed. The geometrical description of a rotational relativistic system is studied and the exact properties of Birkhoff's equations and their forms on R×T*M for a rotational relativistic system are obtained. The global analysis of Birkhoff's equations for a rotational relativistic system is studied, the global properties of autonomous, semi-autonomous and non-autonomous rotational relativistic Birkhoff's equations and the geometrical properties of energy change for rotational relativistic Birkhoff's equations are given.

  4. Spontaneous rotation in a driven mechanical system

    NASA Astrophysics Data System (ADS)

    Alexander, T. J.

    2016-06-01

    We show that a mass free to circulate around a shaken pivot point exhibits resonance-like effects and large amplitude dynamics even though there is no natural frequency in the system, simply through driving under geometrical constraint. We find that synchronization between force and mass occurs over a wide range of forcing amplitudes and frequencies, even when the forcing axis is dynamically, and randomly, changed. Above a critical driving amplitude the mass will spontaneously rotate, with a fractal boundary dividing clockwise and anti-clockwise rotations. We show that this has significant implications for energy harvesting, with large output power over a wide frequency range. We examine also the effect of driving symmetry on the resultant dynamics, and show that if the shaking is circular the motion becomes constrained, whereas for anharmonic rectilinear shaking the dynamics may become chaotic, with the system mimicking that of the kicked rotor.

  5. HST and Spitzer Rotational Phase Mapping of Brown Dwarf Atmospheres

    NASA Astrophysics Data System (ADS)

    Apai, Daniel; Buenzli, E.; Radigan, J.; Burrows, A. S.; Metchev, S. A.; Flateau, D. C.; Reid, I. N.; Heinze, A.; Jayawardhana, R.

    2013-01-01

    The physics and chemistry of condensate clouds play pivotal but poorly understood roles in the atmospheric structure and composition of ultracool brown dwarfs and giant exoplanets. Unresolved observations can only provide limited insights into the structure of clouds or the processes behind the transition from the cloudy L-type sources to the cloud-free T-type ones. We will review exciting results from a new technique, rotational phase mapping, of ultracool atmospheres. Using precision infrared Spitzer photometry and HST spectroscopy covering entire rotation periods of brown dwarfs, we have obtained detailed spectrally and spatially resolved information of their atmospheres. The key results include the identification of cloud structures in L/T brown dwarfs, evidence for longitudinal and vertical cloud heterogeneities, and spectral constraints on the composition and types of clouds. We show that L/T transition brown dwarfs often have thin cloud covers with patches of cold, thick clouds, which introduce strong but only weakly wavelength-dependent extinction. The same thick cloud patches seen in our varying brown dwarf targets, if extended to the entire surface, predict near-infrared colors/magnitudes matching the range occupied by the "underluminous" directly imaged exoplanets. This supports the models in which thick clouds are responsible for the near-infrared properties of underluminous exoplanets.

  6. Stochastic Rotation Dynamics simulations of wetting multi-phase flows

    NASA Astrophysics Data System (ADS)

    Hiller, Thomas; Sanchez de La Lama, Marta; Brinkmann, Martin

    2016-06-01

    Multi-color Stochastic Rotation Dynamics (SRDmc) has been introduced by Inoue et al. [1,2] as a particle based simulation method to study the flow of emulsion droplets in non-wetting microchannels. In this work, we extend the multi-color method to also account for different wetting conditions. This is achieved by assigning the color information not only to fluid particles but also to virtual wall particles that are required to enforce proper no-slip boundary conditions. To extend the scope of the original SRDmc algorithm to e.g. immiscible two-phase flow with viscosity contrast we implement an angular momentum conserving scheme (SRD+mc). We perform extensive benchmark simulations to show that a mono-phase SRDmc fluid exhibits bulk properties identical to a standard SRD fluid and that SRDmc fluids are applicable to a wide range of immiscible two-phase flows. To quantify the adhesion of a SRD+mc fluid in contact to the walls we measure the apparent contact angle from sessile droplets in mechanical equilibrium. For a further verification of our wettability implementation we compare the dewetting of a liquid film from a wetting stripe to experimental and numerical studies of interfacial morphologies on chemically structured surfaces.

  7. A Rotational Pressure-Correction Scheme for Incompressible Two-Phase Flows with Open Boundaries

    PubMed Central

    Dong, S.; Wang, X.

    2016-01-01

    Two-phase outflows refer to situations where the interface formed between two immiscible incompressible fluids passes through open portions of the domain boundary. We present several new forms of open boundary conditions for two-phase outflow simulations within the phase field framework, as well as a rotational pressure correction based algorithm for numerically treating these open boundary conditions. Our algorithm gives rise to linear algebraic systems for the velocity and the pressure that involve only constant and time-independent coefficient matrices after discretization, despite the variable density and variable viscosity of the two-phase mixture. By comparing simulation results with theory and the experimental data, we show that the method produces physically accurate results. We also present numerical experiments to demonstrate the long-term stability of the method in situations where large density contrast, large viscosity contrast, and backflows occur at the two-phase open boundaries. PMID:27163909

  8. A Rotational Pressure-Correction Scheme for Incompressible Two-Phase Flows with Open Boundaries.

    PubMed

    Dong, S; Wang, X

    2016-01-01

    Two-phase outflows refer to situations where the interface formed between two immiscible incompressible fluids passes through open portions of the domain boundary. We present several new forms of open boundary conditions for two-phase outflow simulations within the phase field framework, as well as a rotational pressure correction based algorithm for numerically treating these open boundary conditions. Our algorithm gives rise to linear algebraic systems for the velocity and the pressure that involve only constant and time-independent coefficient matrices after discretization, despite the variable density and variable viscosity of the two-phase mixture. By comparing simulation results with theory and the experimental data, we show that the method produces physically accurate results. We also present numerical experiments to demonstrate the long-term stability of the method in situations where large density contrast, large viscosity contrast, and backflows occur at the two-phase open boundaries. PMID:27163909

  9. Geometric Phase Of The Faraday Rotation Of Electromagnetic Waves In Magnetized Plasma

    SciTech Connect

    Jian Liu and Hong Qin

    2011-11-07

    The geometric phase of circularly polarized electromagnetic waves in nonuniform magnetized plasmas is studied theoretically. The variation of the propagation direction of circularly polarized waves results in a geometric phase, which also contributes to the Faraday rotation, in addition to the standard dynamical phase. The origin and properties of the geometric phase is investigated. The in uence of the geometric phase to plasma diagnostics using Faraday rotation is also discussed as an application of the theory.

  10. Geometric phases of the Faraday rotation of electromagnetic waves in magnetized plasmas

    SciTech Connect

    Liu Jian; Qin Hong

    2012-10-15

    Geometric phases of circularly polarized electromagnetic waves in nonuniform magnetized plasmas is studied theoretically. The variation of the propagation direction of circularly polarized waves results in a geometric phase, which also contributes to the Faraday rotation, in addition to the standard dynamical phase. The origin and properties of the geometric phase are investigated. The influence of the geometric phase to plasma diagnostics using the Faraday rotation is discussed as an application of the theory.

  11. Multiple operating system rotation environment moving target defense

    DOEpatents

    Evans, Nathaniel; Thompson, Michael

    2016-03-22

    Systems and methods for providing a multiple operating system rotation environment ("MORE") moving target defense ("MTD") computing system are described. The MORE-MTD system provides enhanced computer system security through a rotation of multiple operating systems. The MORE-MTD system increases attacker uncertainty, increases the cost of attacking the system, reduces the likelihood of an attacker locating a vulnerability, and reduces the exposure time of any located vulnerability. The MORE-MTD environment is effectuated by rotation of the operating systems at a given interval. The rotating operating systems create a consistently changing attack surface for remote attackers.

  12. Current-induced rotational torques in the skyrmion lattice phase of chiral magnets

    SciTech Connect

    Everschor, Karin; Garst, Markus; Rosch, Achim; Duine, R. A.

    2011-08-01

    In chiral magnets without inversion symmetry, the magnetic structure can form a lattice of magnetic whirl lines, a two-dimensional skyrmion lattice, stabilized by spin-orbit interactions in a small range of temperatures and magnetic fields. The twist of the magnetization within this phase gives rise to an efficient coupling of macroscopic magnetic domains to spin currents. We analyze the resulting spin-transfer effects, and, in particular, focus on the current-induced rotation of the magnetic texture by an angle. Such a rotation can arise from macroscopic temperature gradients in the system as has recently been shown experimentally and theoretically. Here we investigate an alternative mechanism, where small distortions of the skyrmion lattice and the transfer of angular momentum to the underlying atomic lattice play the key role. We employ the Landau-Lifshitz-Gilbert equation and adapt the Thiele method to derive an effective equation of motion for the rotational degree of freedom. We discuss the dependence of the rotation angle on the orientation of the applied magnetic field and the distance to the phase transition.

  13. Counter-Rotating Tandem Motor Drilling System

    SciTech Connect

    Kent Perry

    2009-04-30

    Gas Technology Institute (GTI), in partnership with Dennis Tool Company (DTC), has worked to develop an advanced drill bit system to be used with microhole drilling assemblies. One of the main objectives of this project was to utilize new and existing coiled tubing and slimhole drilling technologies to develop Microhole Technology (MHT) so as to make significant reductions in the cost of E&P down to 5000 feet in wellbores as small as 3.5 inches in diameter. This new technology was developed to work toward the DOE's goal of enabling domestic shallow oil and gas wells to be drilled inexpensively compared to wells drilled utilizing conventional drilling practices. Overall drilling costs can be lowered by drilling a well as quickly as possible. For this reason, a high drilling rate of penetration is always desired. In general, high drilling rates of penetration (ROP) can be achieved by increasing the weight on bit and increasing the rotary speed of the bit. As the weight on bit is increased, the cutting inserts penetrate deeper into the rock, resulting in a deeper depth of cut. As the depth of cut increases, the amount of torque required to turn the bit also increases. The Counter-Rotating Tandem Motor Drilling System (CRTMDS) was planned to achieve high rate of penetration (ROP) resulting in the reduction of the drilling cost. The system includes two counter-rotating cutter systems to reduce or eliminate the reactive torque the drillpipe or coiled tubing must resist. This would allow the application of maximum weight-on-bit and rotational velocities that a coiled tubing drilling unit is capable of delivering. Several variations of the CRTDMS were designed, manufactured and tested. The original tests failed leading to design modifications. Two versions of the modified system were tested and showed that the concept is both positive and practical; however, the tests showed that for the system to be robust and durable, borehole diameter should be substantially larger than

  14. Rotation-Enabled 7-Degree of Freedom Seismometer for Geothermal Resource Development. Phase 1 Final Report

    SciTech Connect

    Pierson, Bob; Laughlin, Darren

    2013-10-29

    Under this Department of Energy (DOE) grant, A-Tech Corporation d.b.a. Applied Technology Associates (ATA), seeks to develop a seven-degree-of-freedom (7-DOF) seismic measurement tool for high-temperature geothermal applications. The Rotational-Enabled 7-DOF Seismometer includes a conventional tri-axial accelerometer, a conventional pressure sensor or hydrophone, and a tri-axial rotational sensor. The rotational sensing capability is novel, based upon ATA's innovative research in rotational sensing technologies. The geothermal industry requires tools for high-precision seismic monitoring of crack formation associated with Enhanced Geothermal System (EGS) stimulation activity. Currently, microseismic monitoring is conducted by deploying many seismic tools at different depth levels along a 'string' within drilled observation wells. Costs per string can be hundreds of thousands of dollars. Processing data from the spatial arrays of linear seismometers allows back-projection of seismic wave states. In contrast, a Rotational-Enabled 7-DOF Seismometer would simultaneously measure p-wave velocity, s-wave velocity, and incident seismic wave direction all from a single point measurement. In addition, the Rotational-Enabled 7-DOF Seismometer will, by its nature, separate p- and s-waves into different data streams, simplifying signal processing and facilitating analysis of seismic source signatures and geological characterization. By adding measurements of three additional degrees-of-freedom at each level and leveraging the information from this new seismic observable, it is likely that an equally accurate picture of subsurface seismic activity could be garnered with fewer levels per hole. The key cost savings would come from better siting of the well due to increased information content and a decrease in the number of confirmation wells drilled, also due to the increase in information per well. Improved seismic tools may also increase knowledge, understanding, and confidence

  15. Phase-space analysis of charged and optical beam transport: Wigner rotation angle

    NASA Technical Reports Server (NTRS)

    Dattoli, G.; Torre, Amalia

    1994-01-01

    The possibility of using the phase space formalism to establish a correspondence between the dynamical behavior of squeezed states and optical or charged beams, propagating through linear systems, has received a great deal of attention during the last years. In this connection, it has been indicated how optical experiments may be conceived to measure the Wigner rotation angle. In this paper we address the topic within the context of the paraxial propagation of optical or charged beams and suggest a possible experiment for measuring the Wigner angle using an electron beam passing through quadrupoles and drift sections. The analogous optical system is also discussed.

  16. Stress field rotation or block rotation: An example from the Lake Mead fault system

    NASA Technical Reports Server (NTRS)

    Ron, Hagai; Nur, Amos; Aydin, Atilla

    1990-01-01

    The Coulomb criterion, as applied by Anderson (1951), has been widely used as the basis for inferring paleostresses from in situ fault slip data, assuming that faults are optimally oriented relative to the tectonic stress direction. Consequently if stress direction is fixed during deformation so must be the faults. Freund (1974) has shown that faults, when arranged in sets, must generally rotate as they slip. Nur et al., (1986) showed how sufficiently large rotations require the development of new sets of faults which are more favorably oriented to the principal direction of stress. This leads to the appearance of multiple fault sets in which older faults are offset by younger ones, both having the same sense of slip. Consequently correct paleostress analysis must include the possible effect of fault and material rotation, in addition to stress field rotation. The combined effects of stress field rotation and material rotation were investigated in the Lake Meade Fault System (LMFS) especially in the Hoover Dam area. Fault inversion results imply an apparent 60 degrees clockwise (CW) rotation of the stress field since mid-Miocene time. In contrast structural data from the rest of the Great Basin suggest only a 30 degrees CW stress field rotation. By incorporating paleomagnetic and seismic evidence, the 30 degrees discrepancy can be neatly resolved. Based on paleomagnetic declination anomalies, it is inferred that slip on NW trending right lateral faults caused a local 30 degrees counter-clockwise (CCW) rotation of blocks and faults in the Lake Mead area. Consequently the inferred 60 degrees CW rotation of the stress field in the LMFS consists of an actual 30 degrees CW rotation of the stress field (as for the entire Great Basin) plus a local 30 degrees CCW material rotation of the LMFS fault blocks.

  17. Studies of chondrogenesis in rotating systems

    NASA Technical Reports Server (NTRS)

    Duke, P. J.; Daane, E. L.; Montufar-Solis, D.

    1993-01-01

    A great deal of energy has been exerted over the years researching methods for regenerating and repairing bone and cartilage. Several techniques, especially bone implants and grafts, show great promise for providing a remedy for many skeletal disorders and chondrodystrophies. The bioreactor (rotating-wall vessel, RWV) is a cell culture system that creates a nurturing environment conducive to cell aggregation. Chondrocyte cultures have been studied as implants for repair and replacement of damaged and missing bone and cartilage since 1965 [Chesterman and Smith, J Bone Joint Surg 50B:184-197, 1965]. The ability to use large, tissue-like cartilage aggregates grown in the RWV would be of great clinical significance in treating skeletal disorders. In addition, the RWV may provide a superior method for studying chondrogenesis and chondrogenic mutations. Because the RWV is also reported to simulate many of the conditions of microgravity it is a very useful ground-based tool for studying how cell systems will react to microgravity.

  18. Rotation of water molecules in plastic phase at extreme conditions from first principles molecular dynamics method

    NASA Astrophysics Data System (ADS)

    Tasaka, Tomofumi; Tsumuraya, Kazuo

    2014-03-01

    Water has a variety of polymorphs in wide ranges of temperature and pressure. Ice VII phase transforms to ice X with increased pressure. However the ice VII transforms to a superionic phase at higher temperatures around 2000K and pressure 30GPa in which the protons migrate in the body centered cubic lattice of oxygens. The ice VII transforms into rotator phase (so called plastic phase at lower temperatures around 600K and 5 to 50GPa. The formation of the phase has been confirmed only with the empirical potentials, whereas the experimental confirmation has been postponed until now. The present study elucidates the mechanism of the rotation of the water molecules and the correlation between the molecules during the rotation with the first principles molecular dynamics method. The water molecules rotate around each oxygen atom to conserve the ice VII positions of the protons.

  19. Some dynamic problems of rotating windmill systems

    NASA Technical Reports Server (NTRS)

    Dugundji, J.

    1976-01-01

    The basic whirl stability of a rotating windmill on a flexible tower is reviewed. Effects of unbalance, gravity force, gyroscopic moments, and aerodynamics are discussed. Some experimental results on a small model windmill are given.

  20. Effect of vibration on two-liquid system in rotating cylinder

    NASA Astrophysics Data System (ADS)

    Kozlov, Nikolai V.; Shuvalova, Darya A.

    2016-10-01

    Behavior of two immiscible liquids of different densities is experimentally investigated in a rotating horizontal cylinder subject to vibrations perpendicular to the axis of rotation. The vibration frequency is comparable to the frequency of rotation. The liquids are centrifuged. The resonant excitation of two-dimensional circular oscillations of light liquid column with respect to the cavity is found. The oscillations can occur both in the direction of the cavity rotation and in the opposite direction and are accompanied, respectively, by a leading or lagging azimuthal motion of the interface relative to the cavity. The existence and direction of the azimuthal motion are determined by the relative frequency of vibrations. The oscillations of the light phase have inertial nature and are caused by the difference in densities of two liquids. The influence of liquids properties on the frequency eigenvalues of circular liquid oscillations and on the intensity of differential rotation is studied. A comparison with the results of other authors who have investigated two-phase cylindrical systems under rotation is made. It is shown that the two-dimensional circular mode of fluid oscillations is typical for rotating two-phase systems as follows from the general character of such parameters as the density ratio and volume ratio.

  1. Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

    PubMed

    Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

    2016-04-18

    The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7. PMID:27137299

  2. Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

    PubMed

    Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

    2016-04-18

    The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

  3. Rotating pressure measuring system for turbine cooling investigations

    NASA Technical Reports Server (NTRS)

    Pollack, F. G.; Liebert, C. H.; Peterson, V. S.

    1972-01-01

    The development of a 10-channel rotating pressure measuring system capable of operation to speeds of 9000 rpm at transducer temperatures of about 320 K (120 F) is described. Variable-reluctance pressure transducers were mounted in the rotating system for sensing pressure. Rotating performance tests on a spin rig showed that the output data from 7 of the 10 transducers tested were within a desired system error of 3 percent. However, the error of the output data from three other transducers was as large as 8 percent of 9000 rpm. It was concluded from these test results that a rotating screening method was necessary to evaluate each pressure transducer channel within a system that will be used under rotating conditions.

  4. Prediction and removal of rotation noise in airborne EM systems

    NASA Astrophysics Data System (ADS)

    Kratzer, Terence 12Macnae, James

    2014-03-01

    We aim to eliminate or reduce significant impediments to conductive target detection and conductive cover penetration in airborne electromagnetic (AEM) systems. Existing limitations come from the very high noise encountered at low base frequencies, caused by rotations of vector magnetic field sensors in the Earth's magnetic field. We use the output of tri-axial rotation-rate sensors to predict and subtract the rotation noise from rigidly coupled ARMIT magnetic field sensors. The approach is successful in reducing rotation noise by one to two orders of magnitude at low frequencies.

  5. A description of rotations for DEM models of particle systems

    NASA Astrophysics Data System (ADS)

    Campello, Eduardo M. B.

    2015-06-01

    In this work, we show how a vector parameterization of rotations can be adopted to describe the rotational motion of particles within the framework of the discrete element method (DEM). It is based on the use of a special rotation vector, called Rodrigues rotation vector, and accounts for finite rotations in a fully exact manner. The use of fictitious entities such as quaternions or complicated structures such as Euler angles is thereby circumvented. As an additional advantage, stick-slip friction models with inter-particle rolling motion are made possible in a consistent and elegant way. A few examples are provided to illustrate the applicability of the scheme. We believe that simple vector descriptions of rotations are very useful for DEM models of particle systems.

  6. Modal identification of a rotating-blade system

    SciTech Connect

    Carne, T.G.; Martinez, D.R.; Ibrahim, S.R.

    1983-01-01

    A new testing technique and the Ibrahim time domain (ITD) modal identification algorithm have been combined, resulting in a capability to estimate modal parameters for rotating blade systems. This capability has been evaluated on the Sandia two-meter, vertical-axis wind turbine. Variation in modal frequencies as a function of rotation speed has been experimentally determined from 0 rpm (parked) to 800 rpm. Excitation of the rotating turbine was provided by a scheme which suddenly released a pretensioned cable, thus plucking the turbine as it rotated. The structural response was obtained by passing the signals through slip rings. Using the measured free-decay responses as input for the ITD algorithm, the modes of the rotating turbine were determined at seven rotation speeds. The measured modal parameters were compared with analytical results obtained from a finite element analysis and with experimental results obtained from a complex exponential identification algorithm.

  7. Modal identification of a rotating-blade system

    SciTech Connect

    Carne, T.G.; Martinez, D.R.; Ibrahim, S.R.

    1983-04-01

    A new testing technique and the Ibrahim time-domain (ITD) modal identification algorithm have been combined, resulting in a capability to estimate modal parameters for rotating-blade systems. This capability has been evaluated on the Sandia two-meter, vertical-axis wind turbine. Variation in modal frequencies as a function of rotation speed has been experimentally determined from 0 rpm (parked) to 800 rpm. Excitation of the rotating turbine was provided by a scheme which suddenly released a pretensioned cable, thus plucking the turbine as it rotated. The structural response was obtained by passing the signals through slip rings. Using the measured free-decay responses as input data for the ITD algorithm, the modes of the rotating turbine were determined at seven rotation speeds. The measured modal parameters were compared with analytical results obtained from a finite element analysis and with experimental results obtained from a complex exponential identification algorithm.

  8. Research of optical rotation measurement system based on centroid algorithm

    NASA Astrophysics Data System (ADS)

    Cao, Junjie; Jia, Hongzhi; Shen, Xinrong; Jiang, Shixin

    2016-09-01

    An optical rotation measurement system based on digital signal processor, modulated laser, and step motor rotating stage is established. Centroid algorithm featured fast and simple calculation is introduced to process light signals with or without sample to obtain the optical rotating angle through the step difference between two centroids. The system performance is proved experimentally with standard quartz tubes and glucose solutions. After various measurements, the relative error and precision of the system are determined to 0.4% and 0.004°, which demonstrates the reliable repeatability and high accuracy of whole measurement system.

  9. Suspension System Provides Independent Translation And Rotation

    NASA Technical Reports Server (NTRS)

    Heeg, Jennifer

    1994-01-01

    Spring suspension provides one translational and one rotational degree of freedom. Suspension used to provide for pitching and plunging movements of airfoil in wind tunnel. Translational freedom provided by two thin, flat steel spring tines, clamped at one end to stationary block fixed to ceiling of wind tunnel, and clamped to movable block at other end.

  10. Rotating Rod Renewable Microcolumns for Automated, Solid-Phase DNA Hybridization

    SciTech Connect

    Bruckner-Lea, Cynthia J. ); Stottlemyre, Mark R.; Holman, David A.; Grate, Jay W. ); Brockman, Fred J. ); Chandler, Darrell P.

    1999-12-01

    The development of a new temperature-controlled renewable microcolumn flow cell for solid-phase nucleic acid analysis in a sequential injection system is described. The flow cell includes a stepper motor-driven rotating rod with the working end cut to a 45 degree angle. In one position, the end of the rod prevents passage of microbeads while allowing fluid flow; rotation of the rod by 180 degrees release the beads. This system was used to rapidly test many hybridization and elution protocols to examine the temperature and solution conditions required for sequence specific nucleic acid hybridization. Target nucleic acids labeled with a near-infrared fluorescent dye were detected immediately post-column using a flow-through fluorescence detector, with a detection limit of 40 pM dye concentration at a flow rate of 5 mu l/s. Temperature control of the column and the presence of Triton X-100 surfactant were critical for specific hybridization. Perfusion of the column with complementary oligonucleotide (200 mu l, 10nM) resulted in hybridization with 8% of the DNA binding sites on the microbeads with a solution residence time of less than a second and a total sample perfusion time of 40 seconds. The use of the renewable column system for detection of an unlabeled PCR product in a sandwich assay was also demonstrated.

  11. Rotating rod renewable microcolumns for automated, solid-phase DNA hybridization studies.

    PubMed

    Bruckner-Lea, C J; Stottlemyre, M S; Holman, D A; Grate, J W; Brockman, F J; Chandler, D P

    2000-09-01

    The development of a new temperature-controlled renewable microcolumn flow cell for solid-phase nucleic acid hybridization in an automated sequential injection system is described. The flow cell included a stepper motor-driven rotating rod with the working end cut to a 45 degrees angle. In one position, the end of the rod prevented passage of microbeads while allowing fluid flow; rotation of the rod by 180 degrees releases the beads. This system was used to rapidly test many hybridization and elution protocols to examine the temperature and solution conditions required for sequence-specific nucleic acid hybridization. Target nucleic acids labeled with a near-infrared fluorescent dye were detected immediately postcolumn during all column perfusion and elution steps using a flow-through fluorescence detector. Temperature control of the column and the presence of Triton X-100 surfactant were critical for specific hybridization. Perfusion of the column with complementary oligonucleotide (200 microL, 10 nM) resulted in hybridization with 8% of the DNA binding sites on the microbeads with a solution residence time of less than 1 s and a total sample perfusion time of 40 s. The use of the renewable column system for detection of an unlabeled PCR product in a sandwich assay was also demonstrated. PMID:10994975

  12. Rotating rod renewable microcolumns for automated, solid-phase DNA hybridization studies.

    PubMed

    Bruckner-Lea, C J; Stottlemyre, M S; Holman, D A; Grate, J W; Brockman, F J; Chandler, D P

    2000-09-01

    The development of a new temperature-controlled renewable microcolumn flow cell for solid-phase nucleic acid hybridization in an automated sequential injection system is described. The flow cell included a stepper motor-driven rotating rod with the working end cut to a 45 degrees angle. In one position, the end of the rod prevented passage of microbeads while allowing fluid flow; rotation of the rod by 180 degrees releases the beads. This system was used to rapidly test many hybridization and elution protocols to examine the temperature and solution conditions required for sequence-specific nucleic acid hybridization. Target nucleic acids labeled with a near-infrared fluorescent dye were detected immediately postcolumn during all column perfusion and elution steps using a flow-through fluorescence detector. Temperature control of the column and the presence of Triton X-100 surfactant were critical for specific hybridization. Perfusion of the column with complementary oligonucleotide (200 microL, 10 nM) resulted in hybridization with 8% of the DNA binding sites on the microbeads with a solution residence time of less than 1 s and a total sample perfusion time of 40 s. The use of the renewable column system for detection of an unlabeled PCR product in a sandwich assay was also demonstrated.

  13. Semiclassical shell structure in rotating Fermi systems

    SciTech Connect

    Magner, A. G.; Sitdikov, A. S.; Khamzin, A. A.; Bartel, J.

    2010-06-15

    The collective moment of inertia is derived analytically within the cranking model for any rotational frequency of the harmonic-oscillator potential well and at a finite temperature. Semiclassical shell-structure components of the collective moment of inertia are obtained for any potential by using the periodic-orbit theory. We found semiclassically their relation to the free-energy shell corrections through the shell-structure components of the rigid-body moment of inertia of the statistically equilibrium rotation in terms of short periodic orbits. The shell effects in the moment of inertia exponentially disappear with increasing temperature. For the case of the harmonic-oscillator potential, one observes a perfect agreement of the semiclassical and quantum shell-structure components of the free energy and the moment of inertia for several critical bifurcation deformations and several temperatures.

  14. Probing Vitamine C, Aspirin and Paracetamol in the Gas Phase: High Resolution Rotational Studies

    NASA Astrophysics Data System (ADS)

    Mata, S.; Cabezas, C.; Varela, M.; Pena, I.; Nino, A.; López, J. C.; Alonso, J. L.; Grabow, J.-U.

    2011-06-01

    A solid sample of Vitamin C (m.p. 190°C) vaporized by laser ablation has been investigated in gas phase and characterized through their rotational spectra. Two spectroscopy techniques has been used to obtain the spectra: a new design of broadband chirped pulse Fourier transform microwave spectroscopy with in-phase/quadrature-phase-modulation passage-acquired-coherence technique (IMPACT) and conventional laser ablation molecular beam Fourier transform microwave spectroscopy (LA-MB-FTMW). Up to now, two low-energy conformer have been observed and their rotational constants determined. Ab initio calculations at the MP2/6-311++G (d,p) level of theory predicted rotational constants which helped us to identify these conformers unequivocally. Among the molecules to benefit from the LA-MB-FTMW technique there are common important drugs never observed in the gas phase through rotational spectroscopy. We present here the results on acetyl salicylic acid and acetaminophen (m.p. 136°C), commonly known as aspirin and paracetamol respectively. We have observed two stable conformers of aspirin and two for paracetamol. The internal rotation barrier of the methyl group in aspirin has been determined for both conformers from the analysis of the A-E splittings due to the coupling of internal and overall rotation. J. L. Alonso, C. Pérez, M. E. Sanz, J. C. López, S. Blanco, Phys. Chem. Chem. Phys. 11,617-627 (2009)and references therein

  15. Rotational Analysis of Phase Plane Curves: Complex and Pure Imaginary Eigenvalues

    ERIC Educational Resources Information Center

    Murray, Russell H.

    2005-01-01

    Although the phase plane can be plotted and analyzed using an appropriate software package, the author found it worthwhile to engage the students with the theorem and the two proofs. The theorem is a powerful tool that provides insight into the rotational behavior of the phase plane diagram in a simple way: just check the signs of c and [alpha].…

  16. Effects of rotation interval on sleepiness and circadian dynamics on forward rotating 3-shift systems.

    PubMed

    Postnova, Svetlana; Postnov, Dmitry D; Seneviratne, Martin; Robinson, Peter A

    2014-02-01

    A physiologically based mathematical model of sleep-wake cycles is used to examine the effects of shift rotation interval (RI) (i.e., the number of days spent on each shift) on sleepiness and circadian dynamics on forward rotating 3-shift schedules. The effects of the schedule start time on the mean shift sleepiness are also demonstrated but are weak compared to the effects of RI. The dynamics are studied for a parameter set adjusted to match a most common natural sleep pattern (i.e., sleep between 0000 and 0800) and for common light conditions (i.e., 350 lux of shift lighting, 200 lux of daylight, 100 lux of artificial lighting during nighttime, and 0 lux during sleep). Mean shift sleepiness on a rotating schedule is found to increase with RI, reach maximum at intermediate RI=6 d, and then decrease. Complete entrainment to shifts within the schedules is not achieved at RI≤10 d. However, circadian oscillations synchronize to the rotation cycles, with RI=1,2 d and RI≥6 d demonstrating regular periodic changes of the circadian rhythm. At rapid rotation, circadian phase stays within a small 4-h interval, whereas slow rotation leads to around-the-clock transitions of the circadian phase with constantly delayed sleep times. Schedules with RI=3-5 d are not able to entrain the circadian rhythms, even in the absence of external circadian disturbances like social commitments and days off. To understand the circadian dynamics on the rotating shift schedules, a shift response map is developed, showing the direction of circadian change (i.e., delay or advance) depending on the relation between the shift start time and actual circadian phase. The map predicts that the un-entrained dynamics come from multiple transitions between advance and delay behavior on the shifts in the schedules. These are primarily caused by the imbalance between the amount of delay and advance on the different shift types within the schedule. Finally, it is argued that shift response maps can aid in

  17. Three-parameter error analysis method based on rotating coordinates in rotating birefringent polarizer system

    SciTech Connect

    Cao, Junjie; Jia, Hongzhi

    2015-11-15

    We propose error analysis using a rotating coordinate system with three parameters of linearly polarized light—incidence angle, azimuth angle on the front surface, and angle between the incidence and vibration planes—and demonstrate the method on a rotating birefringent prism system. The transmittance and angles are calculated plane-by-plane using a birefringence ellipsoid model and the final transmitted intensity equation is deduced. The effects of oblique incidence, light interference, beam convergence, and misalignment of the rotation and prism axes are discussed. We simulate the entire error model using MATLAB and conduct experiments based on a built polarimeter. The simulation and experimental results are consistent and demonstrate the rationality and validity of this method.

  18. Three-parameter error analysis method based on rotating coordinates in rotating birefringent polarizer system.

    PubMed

    Cao, Junjie; Jia, Hongzhi

    2015-11-01

    We propose error analysis using a rotating coordinate system with three parameters of linearly polarized light--incidence angle, azimuth angle on the front surface, and angle between the incidence and vibration planes--and demonstrate the method on a rotating birefringent prism system. The transmittance and angles are calculated plane-by-plane using a birefringence ellipsoid model and the final transmitted intensity equation is deduced. The effects of oblique incidence, light interference, beam convergence, and misalignment of the rotation and prism axes are discussed. We simulate the entire error model using MATLAB and conduct experiments based on a built polarimeter. The simulation and experimental results are consistent and demonstrate the rationality and validity of this method. PMID:26628116

  19. Self-shaping of oil droplets via the formation of intermediate rotator phases upon cooling.

    PubMed

    Denkov, Nikolai; Tcholakova, Slavka; Lesov, Ivan; Cholakova, Diana; Smoukov, Stoyan K

    2015-12-17

    Revealing the chemical and physical mechanisms underlying symmetry breaking and shape transformations is key to understanding morphogenesis. If we are to synthesize artificial structures with similar control and complexity to biological systems, we need energy- and material-efficient bottom-up processes to create building blocks of various shapes that can further assemble into hierarchical structures. Lithographic top-down processing allows a high level of structural control in microparticle production but at the expense of limited productivity. Conversely, bottom-up particle syntheses have higher material and energy efficiency, but are more limited in the shapes achievable. Linear hydrocarbons are known to pass through a series of metastable plastic rotator phases before freezing. Here we show that by using appropriate cooling protocols, we can harness these phase transitions to control the deformation of liquid hydrocarbon droplets and then freeze them into solid particles, permanently preserving their shape. Upon cooling, the droplets spontaneously break their shape symmetry several times, morphing through a series of complex regular shapes owing to the internal phase-transition processes. In this way we produce particles including micrometre-sized octahedra, various polygonal platelets, O-shapes, and fibres of submicrometre diameter, which can be selectively frozen into the corresponding solid particles. This mechanism offers insights into achieving complex morphogenesis from a system with a minimal number of molecular components. PMID:26649824

  20. Self-shaping of oil droplets via the formation of intermediate rotator phases upon cooling.

    PubMed

    Denkov, Nikolai; Tcholakova, Slavka; Lesov, Ivan; Cholakova, Diana; Smoukov, Stoyan K

    2015-12-17

    Revealing the chemical and physical mechanisms underlying symmetry breaking and shape transformations is key to understanding morphogenesis. If we are to synthesize artificial structures with similar control and complexity to biological systems, we need energy- and material-efficient bottom-up processes to create building blocks of various shapes that can further assemble into hierarchical structures. Lithographic top-down processing allows a high level of structural control in microparticle production but at the expense of limited productivity. Conversely, bottom-up particle syntheses have higher material and energy efficiency, but are more limited in the shapes achievable. Linear hydrocarbons are known to pass through a series of metastable plastic rotator phases before freezing. Here we show that by using appropriate cooling protocols, we can harness these phase transitions to control the deformation of liquid hydrocarbon droplets and then freeze them into solid particles, permanently preserving their shape. Upon cooling, the droplets spontaneously break their shape symmetry several times, morphing through a series of complex regular shapes owing to the internal phase-transition processes. In this way we produce particles including micrometre-sized octahedra, various polygonal platelets, O-shapes, and fibres of submicrometre diameter, which can be selectively frozen into the corresponding solid particles. This mechanism offers insights into achieving complex morphogenesis from a system with a minimal number of molecular components.

  1. Self-shaping of oil droplets via the formation of intermediate rotator phases upon cooling

    NASA Astrophysics Data System (ADS)

    Denkov, Nikolai; Tcholakova, Slavka; Lesov, Ivan; Cholakova, Diana; Smoukov, Stoyan K.

    2015-12-01

    Revealing the chemical and physical mechanisms underlying symmetry breaking and shape transformations is key to understanding morphogenesis. If we are to synthesize artificial structures with similar control and complexity to biological systems, we need energy- and material-efficient bottom-up processes to create building blocks of various shapes that can further assemble into hierarchical structures. Lithographic top-down processing allows a high level of structural control in microparticle production but at the expense of limited productivity. Conversely, bottom-up particle syntheses have higher material and energy efficiency, but are more limited in the shapes achievable. Linear hydrocarbons are known to pass through a series of metastable plastic rotator phases before freezing. Here we show that by using appropriate cooling protocols, we can harness these phase transitions to control the deformation of liquid hydrocarbon droplets and then freeze them into solid particles, permanently preserving their shape. Upon cooling, the droplets spontaneously break their shape symmetry several times, morphing through a series of complex regular shapes owing to the internal phase-transition processes. In this way we produce particles including micrometre-sized octahedra, various polygonal platelets, O-shapes, and fibres of submicrometre diameter, which can be selectively frozen into the corresponding solid particles. This mechanism offers insights into achieving complex morphogenesis from a system with a minimal number of molecular components.

  2. Phase Diagram of a 2-D Plane Rotator Model with Integer and Half-Integer Vortices

    NASA Astrophysics Data System (ADS)

    de Souza, Adauto J. F.; Landau, D. P.

    1996-03-01

    A two-dimensional plane rotator spin model is simulated by employing the single cluster embeding Monte Carlo technique and the re-weighting histogram analysis. The system is described by the Hamiltonian^1 \\cal H = -J1 sum_< i,j > Si \\cdot Sj - J2 sum_< i,j > ( Si \\cdot Sj )^2. In adition to the familiar integer vortices, this model possesses half-integer vortex excitations as well. The system exhibits three low-temperature phases which may be identified by the behavior of suitably defined two-point correlation functions. The half- and integer-vortex densities as a function of temperature are calculated for several values of the parameter α = J_2/J_1. The phase boundaries are determined and the nature of the phase transitions is investigated. Research supported in part by the CNPq and the NSF. Permanent address: Departmento de Física e Matemática, Universidade Federal Rural de Pernambuco, 52171-900, Recife, Pernambuco, Brazil ^1 D.H. Lee and G. Grinstein Phys. Rev. Lett. \\underline55, 541, (1985)

  3. Phase transitions in Kr -CH4 solid solutions and rotational excitations in phase II

    NASA Astrophysics Data System (ADS)

    Bagatskii, M. I.; Mashchenko, D. A.; Dudkin, V. V.

    2007-06-01

    The heat capacity CP of Kr-nCH4 solid solutions with CH4 concentrations n =0.82, 0.86, and 0.90 and of solutions with n =0.90, 0.95 doped with 0.002 O2 impurity is investigated under equilibrium vapor pressure over the interval 1-24K. The (T,n) phase diagram of Kr-nCH4 solid solutions is refined, and the region of two-phase states is determined. The contribution of the rotational subsystem, Crot, to the heat capacity of the solutions is separated. Analysis of Crot(T ) at T <3K makes it possible to estimate the effective conversion times τ and the energy gaps E1 and E2 between the tunneling levels of the A ,T and A ,E nuclear-spin species of CH4 molecules in the orientationally ordered subsystem and to determine the effective energy gaps E1 between the lowest levels of the A and T species. The relations τ(n ) and E1(n) stem from changes of the effective potential field in result of the replacement of CH4 molecules by Kr atoms at sites of the ordered sublattices. The effective gaps EL between a group of tunneling levels of the librational ground state and the nearest group of excited levels of the librational state of the ordered CH4 molecules in the solutions with n =0.90 (EL=52K) and 0.95 (EL=55K) is estimated.

  4. Giant vortex phase transition in rapidly rotating trapped Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Correggi, Michele; Pinsker, Florian; Rougerie, Nicolas; Yngvason, Jakob

    2013-02-01

    A Bose-Einstein condensate of cold atoms is a superfluid and thus responds to rotation of its container by the nucleation of quantized vortices. If the trapping potential is sufficiently strong, there is no theoretical limit to the rotation frequency one can impose to the fluid, and several phase transitions characterized by the number and distribution of vortices occur when it is increased from 0 to ∞. In this note we focus on a regime of very large rotation velocity where vortices disappear from the bulk of the fluid, gathering in a central hole of low matter density induced by the centrifugal force.

  5. Rotational Augmentation Disparities in the MEXICO and UAE Phase VI Experiments: Preprint

    SciTech Connect

    Schreck, S.; Sant, T.; Micallef, D.

    2010-05-01

    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.

  6. Muon Bunching and Phase-Energy Rotation for a Neutrino Factory and Muon Collider

    NASA Astrophysics Data System (ADS)

    Neuffer, David; Yoshikawa, Cary

    2008-04-01

    We have developed scenarios for capture, bunching and phase-energy rotation of muons from a proton source, using high-frequency rf systems. The method captures a maximal number of muons into a string of rf bunches with initial application in the neutrino factory design studies. For a muon collider, these bunches must be recombined for maximal luminosity, and our initial design produced a relatively long bunch train. In this paper we present more compact scenarios that obtain a smaller number of bunches, and, after some optimization, obtain cases that are better for both neutrino-factory and collider scenarios. We also consider further modification by incorporating hydrogen gas-filled rf cavities for bunching and cooling. We describe these examples and consider variations toward an optimal factory + collider scenario.

  7. Vibration-rotation line strengths of the gas-phase OH radical

    NASA Technical Reports Server (NTRS)

    Podolske, J.

    1983-01-01

    Absorption line strengths have been measured at 295 K for the first time for four vibration-rotation transitions of the OH radical, using a tunable, infrared diode-laser in conjunction with a molecular modulation spectrometer. A periodically varying OH concentration was created by photolysis, using a sinusoidally modulated 2537-A Hg lamp, of a flowing mixture of O3 and H2O contained within a quartz-walled White cell. The modulated absorption owing to the OH radical was subsequently observed by phase-sensitive detection. The absolute modulation amplitude of the OH number density was obtained by numerical simulation of the complete time-dependent photochemical system. The strongest transition measured was at 3407.607 kaysers, with a strength of 3.3 + or - 1.5 x 10 to the -20th per(cm molecule) sq cm.

  8. Phase-rotated MR spectroscopy using dual-PRESS: theory and application in human brain

    SciTech Connect

    Ramadan, Saadallah; Mountford, Carolyn E.; Thomas, M. Albert

    2007-11-05

    Phase-rotation spectroscopic acquisition is inherently different from the popular signal-averaging method. Phase-rotation will be described theoretically and experimentally in this article. Traditionally, a single echo is acquired in a PRESS or STEAM sequence at a particular TE. If a long-TE spectrum is desired, then another echo is usually acquired at a longer echo time. We here propose a method by which a pair echoes, at short-TE and a long-TE, are acquired in one experiment, thus saving 50% of total acquisition time without significant sacrifice spectral quality. The phase-rotation approach has been implemented with the proposed method. An additional benefit the proposed Dual-PRESS method, is that it gives an insight into the transverse relaxation time constant, T2, for the various metabolites. The Dual-PRESS method is applied in phantom and in-vivo.

  9. Phase-rotated MR spectroscopy using dual-PRESS: theory and application in human brain

    NASA Astrophysics Data System (ADS)

    Ramadan, Saadallah; Thomas, M. Albert; Mountford, Carolyn E.

    2007-11-01

    Phase-rotation spectroscopic acquisition is inherently different from the popular signal-averaging method. Phase-rotation will be described theoretically and experimentally in this article. Traditionally, a single echo is acquired in a PRESS or STEAM sequence at a particular TE. If a long-TE spectrum is desired, then another echo is usually acquired at a longer echo time. We here propose a method by which a pair echoes, at short-TE and a long-TE, are acquired in one experiment, thus saving 50% of total acquisition time without significant sacrifice spectral quality. The phase-rotation approach has been implemented with the proposed method. An additional benefit the proposed Dual-PRESS method, is that it gives an insight into the transverse relaxation time constant, T2, for the various metabolites. The Dual-PRESS method is applied in phantom and in-vivo.

  10. Rotation dependence of a phase delay between plasma edge electron density and temperature fields due to a fast rotating, resonant magnetic perturbation field

    SciTech Connect

    Stoschus, H.; Schmitz, O.; Frerichs, H.; Unterberg, B.; Abdullaev, S. S.; Clever, M.; Coenen, J. W.; Kruezi, U.; Schega, D.; Samm, U.; Jakubowski, M. W.

    2010-06-15

    Measurements of the plasma edge electron density n{sub e} and temperature T{sub e} fields during application of a fast rotating, resonant magnetic perturbation (RMP) field show a characteristic modulation of both, n{sub e} and T{sub e} coherent to the rotation frequency of the RMP field. A phase delay PHI between the n{sub e}(t) and T{sub e}(t) waveforms is observed and it is demonstrated that this phase delay PHI is a function of the radius with PHI(r) depending on the relative rotation of the RMP field and the toroidal plasma rotation. This provides for the first time direct experimental evidence for a rotation dependent damping of the external RMP field in the edge layer of a resistive high-temperature plasma which breaks down at low rotation and high resonant field amplitudes.

  11. Phase boundary of the boson Mott insulator in a rotating optical lattice

    SciTech Connect

    Umucalilar, R. O.; Oktel, M. Oe.

    2007-11-15

    We consider the Bose-Hubbard model in a two-dimensional rotating optical lattice and investigate the consequences of the effective magnetic field created by rotation. Using a Gutzwiller-type variational wave function, we find an analytical expression for the Mott insulator (MI)-superfluid (SF) transition boundary in terms of the maximum eigenvalue of the Hofstadter butterfly. The dependence of phase boundary on the effective magnetic field is complex, reflecting the self-similar properties of the single particle energy spectrum. Finally, we argue that fractional quantum Hall phases exist close to the MI-SF transition boundaries, including MI states with particle densities greater than one.

  12. Simulation of a beam rotation system for a spallation source

    NASA Astrophysics Data System (ADS)

    Reiss, Tibor; Reggiani, Davide; Seidel, Mike; Talanov, Vadim; Wohlmuther, Michael

    2015-04-01

    With a nominal beam power of nearly 1 MW on target, the Swiss Spallation Neutron Source (SINQ), ranks among the world's most powerful spallation neutron sources. The proton beam transport to the SINQ target is carried out exclusively by means of linear magnetic elements. In the transport line to SINQ the beam is scattered in two meson production targets and as a consequence, at the SINQ target entrance the beam shape can be described by Gaussian distributions in transverse x and y directions with tails cut short by collimators. This leads to a highly nonuniform power distribution inside the SINQ target, giving rise to thermal and mechanical stresses. In view of a future proton beam intensity upgrade, the possibility of homogenizing the beam distribution by means of a fast beam rotation system is currently under investigation. Important aspects which need to be studied are the impact of a rotating proton beam on the resulting neutron spectra, spatial flux distributions and additional—previously not present—proton losses causing unwanted activation of accelerator components. Hence a new source description method was developed for the radiation transport code MCNPX. This new feature makes direct use of the results from the proton beam optics code TURTLE. Its advantage to existing MCNPX source options is that all phase space information and correlations of each primary beam particle computed with TURTLE are preserved and transferred to MCNPX. Simulations of the different beam distributions together with their consequences in terms of neutron production are presented in this publication. Additionally, a detailed description of the coupling method between TURTLE and MCNPX is provided.

  13. Analysis of rotation-driven electrokinetic flow in microscale gap regions of rotating disk systems.

    PubMed

    Soong, C Y; Wang, S H

    2004-01-15

    In the present study, a novel theoretical model is developed for the analysis of rotating thermal-fluid flow characteristics in the presence of electrokinetic effects in the microscale gap region between two parallel disks under specified electrostatic, rotational, and thermal boundary conditions. The major flow configuration considered is a rotor-stator disk system. Axisymmetric Navier-Stokes equations with consideration of electric body force stemming from streaming potential are employed in the momentum balance. Variations of the fluid viscosity and permittivity with the local fluid temperature are considered. Between two disks, the axial distribution of the electric potential is determined by the Poisson equation with the concentration distributions of positive and negative ions obtained from Nernst-Planck equations for convection-diffusion of the ions in the flow field. Effects of disk rotation and electrostatic and thermal conditions on the electrokinetic flow and thermal characteristics are investigated. The electrohydrodynamic mechanisms are addressed with an interpretation of the coupling nature of the electric and flow fields. Finally, solutions with electric potential determined by employing nonlinear or linearized Poisson-Boltzmann equation and/or invoking assumptions of constant properties are compared with the predictions of the present model for justification of various levels of approximation in solution of the electrothermal flow behaviors in rotating microfluidic systems. PMID:14654411

  14. Optimizing the rotating point spread function by SLM aided spiral phase modulation

    NASA Astrophysics Data System (ADS)

    Baránek, M.; Bouchal, Z.

    2014-12-01

    We demonstrate the vortex point spread function (PSF) whose shape and the rotation sensitivity to defocusing can be controlled by a phase-only modulation implemented in the spatial or frequency domains. Rotational effects are studied in detail as a result of the spiral modulation carried out in discrete radial and azimuthal sections with different topological charges. As the main result, a direct connection between properties of the PSF and the parameters of the spiral mask is found and subsequently used for an optimal shaping of the PSF and control of its defocusing rotation rate. Experiments on the PSF rotation verify a good agreement with theoretical predictions and demonstrate potential of the method for applications in microscopy, tracking of particles and 3D imaging.

  15. Self-consistent models of quasi-relaxed rotating stellar systems

    NASA Astrophysics Data System (ADS)

    Varri, A. L.; Bertin, G.

    2012-04-01

    Aims: Two new families of self-consistent axisymmetric truncated equilibrium models for the description of quasi-relaxed rotating stellar systems are presented. The first extends the well-known spherical King models to the case of solid-body rotation. The second is characterized by differential rotation, designed to be rigid in the central regions and to vanish in the outer parts, where the imposed energy truncation becomes effective. Methods: The models are constructed by solving the relevant nonlinear Poisson equation for the self-consistent mean-field potential. For rigidly rotating configurations, the solutions are obtained by an asymptotic expansion based on the rotation strength parameter, following a procedure developed earlier by us for the case of tidally generated triaxial models. The differentially rotating models are constructed by means of a spectral iterative approach, with a numerical scheme based on a Legendre series expansion of the density and the potential. Results: The two classes of models exhibit complementary properties. The rigidly rotating configurations are flattened toward the equatorial plane, with deviations from spherical symmetry that increase with the distance from the center. For models of the second family, the deviations from spherical symmetry are strongest in the central region, whereas the outer parts tend to be quasi-spherical. The relevant parameter spaces are thoroughly explored and the corresponding intrinsic and projected structural properties are described. Special attention is given to the effect of different options for the truncation of the distribution function in phase space. Conclusions: Models in the moderate rotation regime are best suited to applications to globular clusters. For general interest in stellar dynamics, at high values of the rotation strength the differentially rotating models tend to exhibit a toroidal core embedded in an otherwise quasi-spherical configuration. Physically simple analytical models

  16. Design of infrared zoom system with rotating lens group

    NASA Astrophysics Data System (ADS)

    Li, Yong; Yang, Changcheng; Li, Shenghui

    2008-03-01

    In surveillance applications there is a need for infrared zoom systems which give two fields of view. For such systems long operation range is the most critical parameter which is bound up with focal length and transmittance of systems. In this paper the design of an infrared zoom system with rotating lens group is described. Different from the conventional axially moving zoom systems, this system is based on a rotating mechanism consisting of two separated lenses. The system achieves dual FOVs due to different magnifications. In narrow field of view mode, the system has long focal length and higher transmittance because the rotating lens group is outside the optical path. The final design is an infrared zoom system operating in 3μm~5μm, with a F number of 4.0, EFL of 250mm/62.5mm. This paper contains the calculation of first-order parameter, the optimum design of rotating motion, the analysis of aberrations, MTF, and Narcissus, This designed system has diffraction limited image quality of in both FOVs.

  17. Phase-locked telemetry system for rotary instrumentation of turbomachinery, phase 1

    NASA Technical Reports Server (NTRS)

    Adler, A.; Hoeks, B.

    1978-01-01

    A telemetry system for use in making strain and temperature measurements on the rotating components of high speed turbomachines employs phase locked transmitters, which offer greater measurement channel capacity and reliability than existing systems which employ L-C carrier oscillators. A prototype transmitter module was tested at 175 C combined with 40,000 g's acceleration.

  18. Combined Solar system and rotation curve constraints on MOND

    NASA Astrophysics Data System (ADS)

    Hees, Aurélien; Famaey, Benoit; Angus, Garry W.; Gentile, Gianfranco

    2016-01-01

    The Modified Newtonian Dynamics (MOND) paradigm generically predicts that the external gravitational field in which a system is embedded can produce effects on its internal dynamics. In this communication, we first show that this external field effect (EFE) can significantly improve some galactic rotation curves fits by decreasing the predicted velocities of the external part of the rotation curves. In modified gravity versions of MOND, this EFE also appears in the Solar system and leads to a very good way to constrain the transition function of the theory. A combined analysis of the galactic rotation curves and Solar system constraints (provided by the Cassini spacecraft) rules out several classes of popular MOND transition functions, but leaves others viable. Moreover, we show that Laser Interferometer Space Antenna Pathfinder will not be able to improve the current constraints on these still viable transition functions.

  19. Gain and phase of perceived virtual rotation evoked by electrical vestibular stimuli.

    PubMed

    Peters, Ryan M; Rasman, Brandon G; Inglis, J Timothy; Blouin, Jean-Sébastien

    2015-07-01

    Galvanic vestibular stimulation (GVS) evokes a perception of rotation; however, very few quantitative data exist on the matter. We performed psychophysical experiments on virtual rotations experienced when binaural bipolar electrical stimulation is applied over the mastoids. We also performed analogous real whole body yaw rotation experiments, allowing us to compare the frequency response of vestibular perception with (real) and without (virtual) natural mechanical stimulation of the semicircular canals. To estimate the gain of vestibular perception, we measured direction discrimination thresholds for virtual and real rotations. Real direction discrimination thresholds decreased at higher frequencies, confirming multiple previous studies. Conversely, virtual direction discrimination thresholds increased at higher frequencies, implying low-pass filtering of the virtual perception process occurring potentially anywhere between afferent transduction and cortical responses. To estimate the phase of vestibular perception, participants manually tracked their perceived position during sinusoidal virtual and real kinetic stimulation. For real rotations, perceived velocity was approximately in phase with actual velocity across all frequencies. Perceived virtual velocity was in phase with the GVS waveform at low frequencies (0.05 and 0.1 Hz). As frequency was increased to 1 Hz, the phase of perceived velocity advanced relative to the GVS waveform. Therefore, at low frequencies GVS is interpreted as an angular velocity signal and at higher frequencies GVS becomes interpreted increasingly as an angular position signal. These estimated gain and phase spectra for vestibular perception are a first step toward generating well-controlled virtual vestibular percepts, an endeavor that may reveal the usefulness of GVS in the areas of clinical assessment, neuroprosthetics, and virtual reality.

  20. B0 insensitive multiple-quantum resolved sodium imaging using a phase-rotation scheme

    NASA Astrophysics Data System (ADS)

    Fiege, Daniel P.; Romanzetti, Sandro; Tse, Desmond H. Y.; Brenner, Daniel; Celik, Avdo; Felder, Jörg; Jon Shah, N.

    2013-03-01

    Triple-quantum filtering has been suggested as a mechanism to differentiate signals from different physiological compartments. However, the filtering method is sensitive to static field inhomogeneities because different coherence pathways may interfere destructively. Previously suggested methods employed additional phase-cycles to separately acquire pathways. Whilst this removes the signal dropouts, it reduces the signal-to-noise per unit time. In this work we suggest the use of a phase-rotation scheme to simultaneously acquire all coherence pathways and then separate them via Fourier transform. Hence the method yields single-, double- and triple-quantum filtered images. The phase-rotation requires a minimum of 36 instead of six cycling steps. However, destructive interference is circumvented whilst maintaining full signal-to-noise efficiency for all coherences.

  1. Spiral vortices traveling between two rotating defects in the Taylor-Couette system

    NASA Astrophysics Data System (ADS)

    Hoffmann, Ch.; Lücke, M.; Pinter, A.

    2005-11-01

    Numerical calculations of vortex flows in Taylor-Couette systems with counter rotating cylinders are presented. The full, time-dependent Navier-Stokes equations are solved with a combination of a finite difference and a Galerkin method. Annular gaps of radius ratio η=0.5 and of several heights are simulated. They are closed by nonrotating lids that produce localized Ekman vortices in their vicinity and that prevent axial phase propagation of spiral vortices. The existence and spatiotemporal properties of rotating defects, modulated Ekman vortices, and the spiral vortex structures in the bulk are elucidated in quantitative detail.

  2. Quantum Hall States in Rotating Spin-1 Bose Systems

    NASA Astrophysics Data System (ADS)

    Read, Nicholas

    2003-03-01

    It has been pointed out that when cold atoms in a trap are rotated rapidly, the system can be mapped onto the quantum Hall effect situation of charged particles in a magnetic field, by passing to the rotating frame. For spinless bosons, as the rotation rate increases, the Bose condensate first develops a vortex lattice, then at high rotation rate this is replaced by a sequence of quantum liquids, which are quantum Hall states of bosons. Numerical work [1] has indicated that there is a sequence of these that are well-described by the parafermion states of Read-Rezayi [2]. For spin-1 bosons, we describe here two sequences of spin-singlet quantum Hall states, with applications to the ground states of a standard model Hamiltonian for this system [3]. We also describe the states at low rotation rates, where various spin textures occur. [1] N.R. Cooper, N.K. Wilkin, and J.M.F. Gunn, Phys. Rev. Lett. 87, 120405 (2001). [2] N. Read and E. Rezayi, Phys. Rev. B 59, 8084 (1999). [3] J.W. Reijnders, F.J.M. Lankvelt, K. Schoutens, and N. Read, Phys. Rev. Lett. 89, 120401 (2002).

  3. Aircraft body-axis rotation measurement system

    NASA Technical Reports Server (NTRS)

    Cowdin, K. T. (Inventor)

    1983-01-01

    A two gyro four gimbal attitude sensing system having gimbal lock avoidance is provided with continuous azimuth information, rather than roll information, relative to the magnetic cardinal headings while in near vertical attitudes to allow recovery from vertical on a desired heading. The system is comprised of a means for stabilizing an outer roll gimbal that is common to a vertical gyro and a directional gyro with respect to the aircraft platform which is being angularly displaced about an axis substantially parallel to the outer roll gyro axis. A means is also provided for producing a signal indicative of the magnitude of such displacement as an indication of aircraft heading. Additional means are provided to cause stabilization of the outer roll gimbal whenever the pitch angle of the aircraft passes through a threshold prior to entering vertical flight and destabilization of the outer roll gimbal upon passing through the threshold when departing vertical flight.

  4. Results from the first preclinical CT scanner with grating based phase contrast and a rotating gantry

    SciTech Connect

    Bech, Martin; Tapfer, Arne; Velroyen, Astrid; Yaroshenko, Andre; Pauwels, Bart; Bruyndonckx, Peter; Liu Xuan; Sasov, Alexander; Mohr, Juergen; Walter, Marco; Pfeiffer, Franz

    2012-07-31

    After successful demonstrations of soft-tissue phase-contrast imaging with grating interferometers at synchrotron radiation sources and at laboratory based x-ray tubes, a first preclinical CT scanner with grating based phase contrast imaging modality has been constructed. The rotating gantry is equipped with a three-grating interferometer, a 50 watt tungsten anode source and a Hamamatsu flat panel detector. The total length of the interferometer is 45 cm, and the bed of the scanner is optimized for mice, with a scanning diameter of 35 mm. From one single scan both phase-contrast and standard attenuation based tomography can be attained, providing an overall gain in image contrast.

  5. Cryogenic cooling with cryocooler on a rotating system.

    PubMed

    Oguri, S; Choi, J; Kawai, M; Tajima, O

    2013-05-01

    We developed a system that continuously maintains a cryocooler for long periods on a rotating table. A cryostat that holds the cryocooler is set on the table. A compressor is located on the ground and supplies high-purity (>99.999%) and high-pressure (1.7 MPa) helium gas and electricity to the cryocooler. The operation of the cryocooler and other instruments requires the development of interface components between the ground and rotating table. A combination of access holes at the center of the table and two rotary joints allows simultaneous circulation of electricity and helium gas. The developed system provides two innovative functions under the rotating condition, cooling from room temperature and the maintenance of a cold condition for long periods. We have confirmed these abilities as well as temperature stability under a condition of continuous rotation at 20 rpm. The developed system can be applied in various fields, e.g., in tests of Lorentz invariance, searches for axion, radio astronomy, and cosmology, and application of radar systems. In particular, there is a plan to use this system for a radio telescope observing cosmic microwave background radiation.

  6. Cryogenic cooling with cryocooler on a rotating system

    NASA Astrophysics Data System (ADS)

    Oguri, S.; Choi, J.; Kawai, M.; Tajima, O.

    2013-05-01

    We developed a system that continuously maintains a cryocooler for long periods on a rotating table. A cryostat that holds the cryocooler is set on the table. A compressor is located on the ground and supplies high-purity (>99.999%) and high-pressure (1.7 MPa) helium gas and electricity to the cryocooler. The operation of the cryocooler and other instruments requires the development of interface components between the ground and rotating table. A combination of access holes at the center of the table and two rotary joints allows simultaneous circulation of electricity and helium gas. The developed system provides two innovative functions under the rotating condition, cooling from room temperature and the maintenance of a cold condition for long periods. We have confirmed these abilities as well as temperature stability under a condition of continuous rotation at 20 rpm. The developed system can be applied in various fields, e.g., in tests of Lorentz invariance, searches for axion, radio astronomy, and cosmology, and application of radar systems. In particular, there is a plan to use this system for a radio telescope observing cosmic microwave background radiation.

  7. Cryogenic cooling with cryocooler on a rotating system.

    PubMed

    Oguri, S; Choi, J; Kawai, M; Tajima, O

    2013-05-01

    We developed a system that continuously maintains a cryocooler for long periods on a rotating table. A cryostat that holds the cryocooler is set on the table. A compressor is located on the ground and supplies high-purity (>99.999%) and high-pressure (1.7 MPa) helium gas and electricity to the cryocooler. The operation of the cryocooler and other instruments requires the development of interface components between the ground and rotating table. A combination of access holes at the center of the table and two rotary joints allows simultaneous circulation of electricity and helium gas. The developed system provides two innovative functions under the rotating condition, cooling from room temperature and the maintenance of a cold condition for long periods. We have confirmed these abilities as well as temperature stability under a condition of continuous rotation at 20 rpm. The developed system can be applied in various fields, e.g., in tests of Lorentz invariance, searches for axion, radio astronomy, and cosmology, and application of radar systems. In particular, there is a plan to use this system for a radio telescope observing cosmic microwave background radiation. PMID:23742598

  8. An Update on Phased Array Results Obtained on the GE Counter-Rotating Open Rotor Model

    NASA Technical Reports Server (NTRS)

    Podboy, Gary; Horvath, Csaba; Envia, Edmane

    2013-01-01

    Beamform maps have been generated from 1) simulated data generated by the LINPROP code and 2) actual experimental phased array data obtained on the GE Counter-rotating open rotor model. The beamform maps show that many of the tones in the experimental data come from their corresponding Mach radius. If the phased array points to the Mach radius associated with a tone then it is likely that the tone is a result of the loading and thickness noise on the blades. In this case, the phased array correctly points to where the noise is coming from and indicates the axial location of the loudest source in the image but not necessarily the correct vertical location. If the phased array does not point to the Mach radius associated with a tone then some mechanism other than loading and thickness noise may control the amplitude of the tone. In this case, the phased array may or may not point to the actual source. If the source is not rotating it is likely that the phased array points to the source. If the source is rotating it is likely that the phased array indicates the axial location of the loudest source but not necessarily the correct vertical location. These results indicate that you have to be careful in how you interpret phased array data obtained on an open rotor since they may show the tones coming from a location other than the source location. With a subsonic tip speed open rotor the tones can come form locations outboard of the blade tips. This has implications regarding noise shielding.

  9. Precision optical angular position marker system for rotating machinery

    NASA Technical Reports Server (NTRS)

    Barranger, J. P.

    1983-01-01

    An optical system is described which generates one or more markers of the angular shaft position of rotating machinery. The system consists of a light source, an optical cable, a machinery mounted lens assembly, a light detector, and a signal conditioner. Light reflected by targets on the rotor is converted to a digital output signal. The system is highly immune to extreme environments of vibration and temperature and achieved a 0.002 percent precision under operational test conditions.

  10. Dynamics of rotating superfluid systems with pinning

    SciTech Connect

    Sedrakyan, A.D.; Sedrakyan, D.M.

    1995-08-01

    Equations describing the dynamics of motion of superfluid systems with pinning are derived, and analytical solutions of these equations are established for the case where the difference between the angular velocities of the superfluid and normal components is small. The solutions can be used to explain the time-dependent behavior of the angular velocity of the Vela pulsar. It is shown that vortex pinning in the period between two consecutive jumps in the pulsar angular velocity can redistribute the vortex number density so as to produce both the observed jump and the after-jump relaxation of the pulsar. For one thing, the formulas obtained are shown to provide an explanation of the 1988 Christmas discontinuity in the angular velocity of the Vela pulsar. 8 refs.

  11. Outcomes of a Rotational Dissection System in Gross Anatomy

    ERIC Educational Resources Information Center

    Marshak, David W.; Oakes, Joanne; Hsieh, Pei-Hsuan; Chuang, Alice Z.; Cleary, Leonard J.

    2015-01-01

    At the University of Texas Houston Medical School, a rotational dissection system was introduced to improve coordination between the Gross Anatomy and the Introduction to Clinical Medicine (ICM) courses. Six students were assigned to each cadaver and divided into two teams. For each laboratory, one team was assigned to dissect and the other to…

  12. Giant Faraday rotation induced by the Berry phase in bilayer graphene under strong terahertz fields

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Xu, Xiaodong; Liu, Ren-Bao

    2014-04-01

    High-order terahertz (THz) sideband generation in semiconductors is a phenomenon with physics similar to that of high-order harmonic generation but in a regime of much lower frequency. Our previous paper [1] found that the electron-hole pair excited by a weak optical laser can accumulate a Berry phase along a cyclic trajectory under the driving of a strong elliptically polarized THz field. Furthermore, the Berry phase appears as the Faraday rotation angle of the emission signal under short-pulse excitation in monolayer MoS_{2}. In this paper, the theory of the Berry phase in THz extreme nonlinear optics is applied to biased bilayer graphene with Bernal stacking, which has similar Bloch band features and optical properties to monolayer MoS_{2}, such as the time-reversal related valleys and the valley contrasting optical selection rule. However, the biased bilayer graphene has much larger Berry curvature than monolayer MoS_{2}, which leads to a large Berry phase of the quantum trajectory and in turn a giant Faraday rotation of the optical emission (˜1 rad for a THz field with frequency 1 THz and strength 8 kV cm-1). This surprisingly big angle shows that the Faraday rotation can be induced more efficiently by the Berry curvature in momentum space than by the magnetic field in real space. It provides opportunities to use bilayer graphene and THz lasers for ultrafast electro-optical devices.

  13. Gas Phase Rovibrational Spectroscopy of Dmso, PART.I: when a Synchrotron Source Reveals AN Unusual Rotational Behaviour

    NASA Astrophysics Data System (ADS)

    Cuisset, Arnaud; Sadovskii, Dmitrii A.; Pirali, Olivier

    2013-06-01

    Many of us have enjoyed the spectacle of a spinning top influenced by friction: rotating rapidly about a stable stationary axis, the top loses slowly its angular momentum j (and energy), slows down gradually, and then, suddenly, its axis becomes unstable, the top wobbles, and an abrupt change of the top's position follows. In other words, the system undergoes a bifurcation. In the case of the tippe top, rotation about its lower point is stable at low values of angular momentum J and becomes unstable at large J. Something quite similar occurs in a freely rotating dimethylsulfoxyde (DMSO, (CH_3)_2SO) molecule. For the first time in such large polyatomic molecule a quantum bifurcation induced by a gyroscopic destabilization was observed. This unusual phenomenon in rotational dynamics was discovered in the rovibrational states of the bending fundamental ν_{23} band of DMSO whose high-resolution gas phase absorption spectrum was observed along with that of ν_{11} by Cuisset et al. using the exceptional properties of the AILES beamline in the Far-Infrared domain. A. Cuisset, O. Pirali, D. Sadovskii,Phys. Rev. Lett., 109,(094101), 2012. A. Cuisset, L. Nanobashvili, I. Smirnova, R. Bocquet, F. Hindle, G. Mouret, O. Pirali, P. Roy, D. Sadovskii,Chem. Phys. Lett., 492,(30),2010 J. B. Brubach et al., AIP Conf. Proc., 1214, (81), 2010.

  14. Kinematic principles of primate rotational vestibulo-ocular reflex. I. Spatial organization of fast phase velocity axes

    NASA Technical Reports Server (NTRS)

    Hess, B. J.; Angelaki, D. E.

    1997-01-01

    The spatial organization of fast phase velocity vectors of the vestibulo-ocular reflex (VOR) was studied in rhesus monkeys during yaw rotations about an earth-horizontal axis that changed continuously the orientation of the head relative to gravity ("barbecue spit" rotation). In addition to a velocity component parallel to the rotation axis, fast phases also exhibited a velocity component that invariably was oriented along the momentary direction of gravity. As the head rotated through supine and prone positions, torsional components of fast phase velocity axes became prominent. Similarly, as the head rotated through left and right ear-down positions, fast phase velocity axes exhibited prominent vertical components. The larger the speed of head rotation the greater the magnitude of this fast phase component, which was collinear with gravity. The main sequence properties of VOR fast phases were independent of head position. However, peak amplitude as well as peak velocity of fast phases were both modulated as a function of head orientation, exhibiting a minimum in prone position. The results suggest that the fast phases of vestibulo-ocular reflexes not only redirect gaze and reposition the eye in the direction of head motion but also reorient the eye with respect to earth-vertical when the head moves relative to gravity. As further elaborated in the companion paper, the underlying mechanism could be described as a dynamic, gravity-dependent modulation of the coordinates of ocular rotations relative to the head.

  15. Spectral-domain low-coherence interferometry for phase-sensitive measurement of Faraday rotation at multiple depths.

    PubMed

    Yeh, Yi-Jou; Black, Adam J; Akkin, Taner

    2013-10-10

    We describe a method for differential phase measurement of Faraday rotation from multiple depth locations simultaneously. A polarization-maintaining fiber-based spectral-domain interferometer that utilizes a low-coherent light source and a single camera is developed. Light decorrelated by the orthogonal channels of the fiber is launched on a sample as two oppositely polarized circular states. These states reflect from sample surfaces and interfere with the corresponding states of the reference arm. A custom spectrometer, which is designed to simplify camera alignment, separates the orthogonal channels and records the interference-related oscillations on both spectra. Inverse Fourier transform of the spectral oscillations in k-space yields complex depth profiles, whose amplitudes and phase difference are related to reflectivity and Faraday rotation within the sample, respectively. Information along a full depth profile is produced at the camera speed without performing an axial scan for a multisurface sample. System sensitivity for the Faraday rotation measurement is 0.86 min of arc. Verdet constants of clear liquids and turbid media are measured at 687 nm. PMID:24217734

  16. Phase-Oriented Gear Systems

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    2007-01-01

    Phase-oriented gear systems are differential planetary transmissions in which each planet gear has two sets of unequal numbers of teeth indexed at prescribed relative angles (phases). The figure illustrates an application of the phase-oriented gearing concept to a relatively simple speed-reducing differential planetary transmission that includes a sun gear, an idler gear, three identical planet gears, a ground internal ring gear, and an output internal ring gear. Typically, the ground internal ring gear and output internal ring gear have different numbers of teeth, giving rise to a progressive and periodic phase shift between the corresponding pairs of teeth engaged by each successive planet gear. To accommodate this phase shift, it is necessary to introduce a compensating phase shift between the ground-gear-engaging and output-gearengaging sections of each planet gear. This is done by individually orienting each planet gear

  17. Four-phase patterns in forced oscillatory systems

    SciTech Connect

    Lin, A. L.; Hagberg, A.; Ardelea, A.; Swinney, H. L.; Meron, E.

    2000-09-01

    We investigate pattern formation in self-oscillating systems forced by an external periodic perturbation. Experimental observations and numerical studies of reaction-diffusion systems and an analysis of an amplitude equation are presented. The oscillations in each of these systems entrain to rational multiples of the perturbation frequency for certain values of the forcing frequency and amplitude. We focus on the subharmonic resonant case where the system locks at one-fourth the driving frequency, and four-phase rotating spiral patterns are observed at low forcing amplitudes. The spiral patterns are studied using an amplitude equation for periodically forced oscillating systems. The analysis predicts a bifurcation (with increasing forcing) from rotating four-phase spirals to standing two-phase patterns. This bifurcation is also found in periodically forced reaction-diffusion equations, the FitzHugh-Nagumo and Brusselator models, even far from the onset of oscillations where the amplitude equation analysis is not strictly valid. In a Belousov-Zhabotinsky chemical system periodically forced with light we also observe four-phase rotating spiral wave patterns. However, we have not observed the transition to standing two-phase patterns, possibly because with increasing light intensity the reaction kinetics become excitable rather than oscillatory. (c) 2000 The American Physical Society.

  18. Four-phase patterns in forced oscillatory systems

    PubMed

    Lin; Hagberg; Ardelea; Bertram; Swinney; Meron

    2000-09-01

    We investigate pattern formation in self-oscillating systems forced by an external periodic perturbation. Experimental observations and numerical studies of reaction-diffusion systems and an analysis of an amplitude equation are presented. The oscillations in each of these systems entrain to rational multiples of the perturbation frequency for certain values of the forcing frequency and amplitude. We focus on the subharmonic resonant case where the system locks at one-fourth the driving frequency, and four-phase rotating spiral patterns are observed at low forcing amplitudes. The spiral patterns are studied using an amplitude equation for periodically forced oscillating systems. The analysis predicts a bifurcation (with increasing forcing) from rotating four-phase spirals to standing two-phase patterns. This bifurcation is also found in periodically forced reaction-diffusion equations, the FitzHugh-Nagumo and Brusselator models, even far from the onset of oscillations where the amplitude equation analysis is not strictly valid. In a Belousov-Zhabotinsky chemical system periodically forced with light we also observe four-phase rotating spiral wave patterns. However, we have not observed the transition to standing two-phase patterns, possibly because with increasing light intensity the reaction kinetics become excitable rather than oscillatory. PMID:11088896

  19. Four-phase patterns in forced oscillatory systems

    NASA Astrophysics Data System (ADS)

    Lin, A. L.; Hagberg, A.; Ardelea, A.; Bertram, M.; Swinney, H. L.; Meron, E.

    2000-09-01

    We investigate pattern formation in self-oscillating systems forced by an external periodic perturbation. Experimental observations and numerical studies of reaction-diffusion systems and an analysis of an amplitude equation are presented. The oscillations in each of these systems entrain to rational multiples of the perturbation frequency for certain values of the forcing frequency and amplitude. We focus on the subharmonic resonant case where the system locks at one-fourth the driving frequency, and four-phase rotating spiral patterns are observed at low forcing amplitudes. The spiral patterns are studied using an amplitude equation for periodically forced oscillating systems. The analysis predicts a bifurcation (with increasing forcing) from rotating four-phase spirals to standing two-phase patterns. This bifurcation is also found in periodically forced reaction-diffusion equations, the FitzHugh-Nagumo and Brusselator models, even far from the onset of oscillations where the amplitude equation analysis is not strictly valid. In a Belousov-Zhabotinsky chemical system periodically forced with light we also observe four-phase rotating spiral wave patterns. However, we have not observed the transition to standing two-phase patterns, possibly because with increasing light intensity the reaction kinetics become excitable rather than oscillatory.

  20. Digital system of invariant correlation to position and rotation

    NASA Astrophysics Data System (ADS)

    Solorza, Selene; Álvarez-Borrego, Josué

    2010-10-01

    A new correlation digital system invariant to position and rotation is presented. This new algorithm requires low computational cost, because it uses uni-dimensional signatures (vectors). The signature of the target so like the signature of the object to be recognized in the problem image is obtained using a binary ring mask constructed based on the real positive values of the Fourier transform of the corresponding image. In this manner, each image will have one unique binary ring mask, avoiding in this form the relevant information leak. Using linear and non-linear correlations, this methodology is applied first in the identification of the alphabet letters in Arial font style and then in the classification of fossil diatoms images. Also, this system is tested using the diatom images with additive Gaussian noise. The non-linear correlation results were excellent, obtaining in this way a simple but efficient method to achieve rotation and translation invariance pattern recognition.

  1. Dual annular rotating "windowed" nuclear reflector reactor control system

    DOEpatents

    Jacox, Michael G.; Drexler, Robert L.; Hunt, Robert N. M.; Lake, James A.

    1994-01-01

    A nuclear reactor control system is provided in a nuclear reactor having a core operating in the fast neutron energy spectrum where criticality control is achieved by neutron leakage. The control system includes dual annular, rotatable reflector rings. There are two reflector rings: an inner reflector ring and an outer reflector ring. The reflectors are concentrically assembled, surround the reactor core, and each reflector ring includes a plurality of openings. The openings in each ring are capable of being aligned or non-aligned with each other. Independent driving means for each of the annular reflector rings is provided so that reactor criticality can be initiated and controlled by rotation of either reflector ring such that the extent of alignment of the openings in each ring controls the reflection of neutrons from the core.

  2. Phase stable RF transport system

    DOEpatents

    Curtin, Michael T.; Natter, Eckard F.; Denney, Peter M.

    1992-01-01

    An RF transport system delivers a phase-stable RF signal to a load, such as an RF cavity of a charged particle accelerator. A circuit generates a calibration signal at an odd multiple frequency of the RF signal where the calibration signal is superimposed with the RF signal on a common cable that connects the RF signal with the load. Signal isolating diplexers are located at both the RF signal source end and load end of the common cable to enable the calibration to be inserted and extracted from the cable signals without any affect on the RF signal. Any phase shift in the calibration signal during traverse of the common cable is then functionally related to the phase shift in the RF signal. The calibration phase shift is used to control a phase shifter for the RF signal to maintain a stable RF signal at the load.

  3. A new post-phase rotation based dynamic receive beamforming architecture for smartphone-based wireless ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Park, Minsuk; Kang, Jeeun; Lee, Gunho; Kim, Min; Song, Tai-Kyong

    2016-04-01

    Recently, a portable US imaging system using smart devices is highlighted for enhancing the portability of diagnosis. Especially, the system combination can enhance the user experience during whole US diagnostic procedures by employing the advanced wireless communication technology integrated in a smart device, e.g., WiFi, Bluetooth, etc. In this paper, an effective post-phase rotation-based dynamic receive beamforming (PRBF-POST) method is presented for wireless US imaging device integrating US probe system and commercial smart device. In conventional, the frame rate of conventional PRBF (PRBF-CON) method suffers from the large amount of calculations for the bifurcated processing paths of in-phase and quadrature signal components as the number of channel increase. Otherwise, the proposed PRBF-POST method can preserve the frame rate regardless of the number of channels by firstly aggregating the baseband IQ data along the channels whose phase quantization levels are identical ahead of phase rotation and summation procedures on a smart device. To evaluate the performance of the proposed PRBF-POST method, the pointspread functions of PRBF-CON and PRBF-POST methods were compared each other. Also, the frame rate of each PRBF method was measured 20-times to calculate the average frame rate and its standard deviation. As a result, the PRBFCON and PRBF-POST methods indicates identical beamforming performance in the Field-II simulation (correlation coefficient = 1). Also, the proposed PRBF-POST method indicates the consistent frame rate for varying number of channels (i.e., 44.25, 44.32, and 44.35 fps for 16, 64, and 128 channels, respectively), while the PRBF-CON method shows the decrease of frame rate as the number of channel increase (39.73, 13.19, and 3.8 fps). These results indicate that the proposed PRBF-POST method can be more advantageous for implementing the wireless US imaging system than the PRBF-CON method.

  4. NMR system and method having a permanent magnet providing a rotating magnetic field

    DOEpatents

    Schlueter, Ross D [Berkeley, CA; Budinger, Thomas F [Berkeley, CA

    2009-05-19

    Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.

  5. Optimization of the parameters for a rotating, mixed-phase reactor

    NASA Technical Reports Server (NTRS)

    Cleland, J. G.; Kornfeld, D. M.

    1992-01-01

    The motion of small, monodisperse particles in fluid was studied in a horizontal, cylindrical container rotating about its axis. One instigation for the study was the common requirement for mixed-phase, chemical or biological reactors to maintain particles in suspension for extended periods. A cylindrical, rotating reactor can allow long-term particle suspension without particle collisions and resulting agglomeration. The purpose of this study was to verify parametric effects and optimize the time of particle suspension. The theoretical and experimental results were obtained for inert, constant-diameter particles of nearly neutral buoyancy. The centrifugal buoyancy and gravitation terms were both included in the equations of motion. Laser illumination, photography and computer imaging were used to measure experimental particle concentration.

  6. Horizontally rotated cell culture system with a coaxial tubular oxygenator

    NASA Technical Reports Server (NTRS)

    Wolf, David A. (Inventor); Schwarz, Ray P. (Inventor); Trinh, Tinh T. (Inventor)

    1991-01-01

    The present invention relates to a horizontally rotating bioreactor useful for carrying out cell and tissue culture. For processing of mammalian cells, the system is sterilized and fresh fluid medium, microcarrier beads, and cells are admitted to completely fill the cell culture vessel. An oxygen containing gas is admitted to the interior of the permeable membrane which prevents air bubbles from being introduced into the medium. The cylinder is rotated at a low speed within an incubator so that the circular motion of the fluid medium uniformly suspends the microbeads throughout the cylinder during the cell growth period. The unique design of this cell and tissue culture device was initially driven by two requirements imposed by its intended use for feasibility studies for three dimensional culture of living cells and tissues in space by JSC. They were compatible with microgravity and simulation of microgravity in one G. The vessels are designed to approximate the extremely quiescent low shear environment obtainable in space.

  7. The Pluto System At Small Phase Angles

    NASA Astrophysics Data System (ADS)

    Verbiscer, Anne J.; Buie, Marc W.; Binzel, Richard; Ennico, Kimberly; Grundy, William M.; Olkin, Catherine B.; Showalter, Mark Robert; Spencer, John R.; Stern, S. Alan; Weaver, Harold A.; Young, Leslie; New Horizons Science Team

    2016-10-01

    Hubble Space Telescope observations of the Pluto system acquired during the New Horizons encounter epoch (HST Program 13667, M. Buie, PI) span the phase angle range from 0.06 to 1.7 degrees, enabling the measurement and characterization of the opposition effect for Pluto and its satellites at 0.58 microns using HST WFC3/UVIS with the F350LP filter, which has a broadband response and a pivot wavelength of 0.58 microns. At these small phase angles, differences in the opposition effect width and amplitude appear. The small satellites Nix and Hydra both exhibit a very narrow opposition surge, while the considerably larger moon Charon has a broader opposition surge. Microtextural surface properties derived from the shape and magnitude of the opposition surge of each surface contain a record of the collisional history of the system. We combine these small phase angle observations with those made at larger phase angles by the New Horizons Long Range Reconnaissance Imager (LORRI), which also has a broadband response with a pivot wavelength of 0.61 microns, to produce the most complete disk-integrated solar phase curves that we will have for decades to come. Modeling these disk-integrated phase curves generates sets of photometric parameters that will inform spectral modeling of the satellite surfaces as well as terrains on Pluto from spatially resolved New Horizons Ralph Linear Etalon Imaging Spectral Array (LEISA) data from 1.2 to 2.5 microns. Rotationally resolved phase curves of Pluto reveal opposition effects that only appear at phase angles less than 0.1 degree and have widths and amplitudes that are highly dependent on longitude and therefore on Pluto's diverse terrains. The high albedo region informally known as Sputnik Planum dominates the disk-integrated reflectance of Pluto on the New Horizons encounter hemisphere. These results lay the groundwork for observations at true opposition in 2018, when the Pluto system will be observable at phase angles so small that

  8. Phase-linking and the perceived motion during off-vertical axis rotation

    PubMed Central

    Wood, Scott J.; McCollum, Gin

    2010-01-01

    Human off-vertical axis rotation (OVAR) in the dark typically produces perceived motion about a cone, the amplitude of which changes as a function of frequency. This perception is commonly attributed to the fact that both the OVAR and the conical motion have a gravity vector that rotates about the subject. Little-known, however, is that this rotating-gravity explanation for perceived conical motion is inconsistent with basic observations about self-motion perception: (a) that the perceived vertical moves toward alignment with the gravito-inertial acceleration (GIA) and (b) that perceived translation arises from perceived linear acceleration, as derived from the portion of the GIA not associated with gravity. Mathematically proved in this article is the fact that during OVAR these properties imply mismatched phase of perceived tilt and translation, in contrast to the common perception of matched phases which correspond to conical motion with pivot at the bottom. This result demonstrates that an additional perceptual rule is required to explain perception in OVAR. This study investigates, both analytically and computationally, the phase relationship between tilt and translation at different stimulus rates—slow (45°/s) and fast (180°/s), and the three-dimensional shape of predicted perceived motion, under different sets of hypotheses about self-motion perception. We propose that for human motion perception, there is a phase-linking of tilt and translation movements to construct a perception of one’s overall motion path. Alternative hypotheses to achieve the phase match were tested with three-dimensional computational models, comparing the output with published experimental reports. The best fit with experimental data was the hypothesis that the phase of perceived translation was linked to perceived tilt, while the perceived tilt was determined by the GIA. This hypothesis successfully predicted the bottom-pivot cone commonly reported and a reduced sense of tilt

  9. Numerical and Experimental study of secondary flows in a rotating two-phase flow: the tea leaf paradox

    NASA Astrophysics Data System (ADS)

    Calderer, Antoni; Neal, Douglas; Prevost, Richard; Mayrhofer, Arno; Lawrenz, Alan; Foss, John; Sotiropoulos, Fotis

    2015-11-01

    Secondary flows in a rotating flow in a cylinder, resulting in the so called ``tea leaf paradox'', are fundamental for understanding atmospheric pressure systems, developing techniques for separating red blood cells from the plasma, and even separating coagulated trub in the beer brewing process. We seek to gain deeper insights in this phenomenon by integrating numerical simulations and experiments. We employ the Curvilinear Immersed boundary method (CURVIB) of Calderer et al. (J. Comp. Physics 2014), which is a two-phase flow solver based on the level set method, to simulate rotating free-surface flow in a cylinder partially filled with water as in the tea leave paradox flow. We first demonstrate the validity of the numerical model by simulating a cylinder with a rotating base filled with a single fluid, obtaining results in excellent agreement with available experimental data. Then, we present results for the cylinder case with free surface, investigate the complex formation of secondary flow patterns, and show comparisons with new experimental data for this flow obtained by Lavision. Computational resources were provided by the Minnesota Supercomputing Institute.

  10. Indentification of a Rotator Phase of Octamethyl Ferrocene and Correlations Between its Structural and Dynamical Properties

    SciTech Connect

    Asthalter,T.; Sergueev, I.; Van Burck, U.; Dinnebier, R.

    2006-01-01

    The low- and high-temperature phases of octamethyl ferrocene were studied in detail, using high-resolution X-ray powder diffraction, differential scanning calorimetry and nuclear resonant scattering, in particular the novel technique of synchrotron radiation perturbed angular correlations (SRPAC). Much as in the case of an analogous but more unsymmetrical molecule, octamethyl ethinyl ferrocene, the high-temperature phase possesses the space group R{bar 3}m source with lattice parameters a = b = 12.5568(1) Angstroms, c = 9.6045(1) Angstroms, which in the rhombohedral setting correspond to a = 7.9251(1) Angstroms, {alpha}=104.79 degrees. An increase of the volume per formula unit of about 12% across the phase transition is observed. The rotation of the electric field gradient, which can be identified with the rotation of the entire molecule within the lattice, follows Arrhenius behavior with a high activation energy of (40.3 {+-} 3.3)kJ mol{sup -1}. Whereas precursor effects and a change in activation energy were observed for octamethyl ethinyl ferrocene, no such effects are observed for octamethyl ferrocene. We relate this difference to the absence of the ethinyl substituent in octamethyl ferrocene.

  11. Failure Accommodation Tested in Magnetic Suspension Systems for Rotating Machinery

    NASA Technical Reports Server (NTRS)

    Provenza, Andy J.

    2000-01-01

    The NASA Glenn Research Center at Lewis Field and Texas A&M University are developing techniques for accommodating certain types of failures in magnetic suspension systems used in rotating machinery. In recent years, magnetic bearings have become a viable alternative to rolling element bearings for many applications. For example, industrial machinery such as machine tool spindles and turbomolecular pumps can today be bought off the shelf with magnetically supported rotating components. Nova Gas Transmission Ltd. has large gas compressors in Canada that have been running flawlessly for years on magnetic bearings. To help mature this technology and quiet concerns over the reliability of magnetic bearings, NASA researchers have been investigating ways of making the bearing system tolerant to faults. Since the potential benefits from an oil-free, actively controlled bearing system are so attractive, research that is focused on assuring system reliability and safety is justifiable. With support from the Fast Quiet Engine program, Glenn's Structural Mechanics and Dynamics Branch is working to demonstrate fault-tolerant magnetic suspension systems targeted for aerospace engine applications. The Flywheel Energy Storage Program is also helping to fund this research.

  12. Stellar rotation-planetary orbit period commensurability in the HAT-P-11 system

    SciTech Connect

    Béky, Bence; Holman, Matthew J.; Noyes, Robert W.; Kipping, David M.

    2014-06-10

    A number of planet host stars have been observed to rotate with a period equal to an integer multiple of the orbital period of their close planet. We expand this list by analyzing Kepler data of HAT-P-11 and finding a period ratio of 6:1. In particular, we present evidence for a long-lived spot on the stellar surface that is eclipsed by the planet in the same position four times, every sixth transit. We also identify minima in the out-of-transit light curve and confirm that their phase with respect to the stellar rotation is mostly stationary for the 48 month time frame of the observations, confirming the proposed rotation period. For comparison, we apply our methods to Kepler-17 and confirm the findings of Bonomo and Lanza that the period ratio is not exactly 8:1 in that system. Finally, we provide a hypothesis on how interactions between a star and its planet could possibly result in an observed commensurability for systems where the stellar differential rotation profile happens to include a period at some latitude that is commensurable to the planetary orbit.

  13. FOSREM - Fibre-Optic System for Rotational Events&Phenomena Monitoring

    NASA Astrophysics Data System (ADS)

    Jaroszewicz, Leszek; Krajewski, Zbigniew; Kurzych, Anna; Kowalski, Jerzy; Teisseyre, Krzysztof

    2016-04-01

    We present the construction and tests of fiber-optic rotational seismometer named FOSREM (Fibre-Optic System for Rotational Events&Phenomena Monitoring). This presented device is designed for detection and monitoring the one-axis rotational motions, brought about to ground or human-made structures both by seismic events and the creep processes. The presented system works by measuring Sagnac effect and generally consists of two basic elements: optical sensor and electronic part. The optical sensor is based on so-called the minimum configuration of FOG (Fibre-Optic Gyroscope) where the Sagnac effect produces a phase shift between two counter-propagating light beams proportional to the measured rotation speed. The main advantage of the sensor of this type is its complete insensitivity to linear motions and a direct measurement of rotational speed. It may work even when tilted, moreover, used in continuous mode it may record the tilt. The electronic system, involving specific electronic solutions, calculates and records rotational events data by realizing synchronous in a digital form by using 32 bit DSP (Digital Signal Processing). Storage data and system control are realised over the internet by using connection between FOSREM and GSM/GPS. The most significant attribute of our system is possibility to measure rotation in wide range both amplitude up to 10 rad/s and frequency up to 328.12 Hz. Application of the wideband, low coherence and high power superluminescent diode with long fibre loop and suitable low losses optical elements assures the theoretical sensitivity of the system equal to 2·10-8 rad/s/Sqrt(Hz). Moreover, the FOSREM is fully remote controlled as well as is suited for continuous, autonomous work in very long period of time (weeks, months, even years), so it is useful for systematic seismological investigation at any place. Possible applications of this system include seismic monitoring in observatories, buildings, mines and even on glaciers and in

  14. MHD Two-Fluid Flow and Heat Transfer between Two Inclined Parallel Plates in a Rotating System

    PubMed Central

    Sri Ramachandra Murty, P.; Balaji Prakash, G.

    2014-01-01

    Two-phase magnetohydrodynamic convective flow of electrically conducting fluid through an inclined channel is studied under the action of a constant transverse magnetic field in a rotating system. The fluids in the two phases are steady, incompressible, laminar, immiscible, and electrically conducting, having different densities, viscosities, and thermal and electrical conductivities. The transport properties of both the fluids are assumed constant. The bounding infinite inclined parallel plates are maintained at different constant temperatures, making an angle ϕ with the horizontal. Approximate solutions for velocity and temperature distributions are obtained by using a straightforward regular perturbation technique. An in-depth study has been done on the effects of rotation parameter, Hartmann number, inclination angle, the ratio of electrical conductivities, and viscosities of two fluids on the flow. It is observed that the effect of increasing rotation is to decrease the primary velocity. Further it is noticed that as the rotation increases, the secondary velocity increases for smaller rotation, while for larger rotation it decreases. It is also found that the temperature distribution decreases as the rotation increases. PMID:27351017

  15. M-dwarf rapid rotators and the detection of relatively young multiple M-star systems

    SciTech Connect

    Rappaport, S.; Joss, M.; Sanchis-Ojeda, R. E-mail: mattjoss@mit.edu; and others

    2014-06-20

    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 transforms, inspection of folded light curves, 'sonograms', and phase tracking of individual modulation cycles, were applied in order to distinguish the periodicities due to rapid rotation from those due to stellar pulsations, eclipsing binaries, or transiting planets. We find 178 Kepler M-star targets with rotation periods, P {sub rot}, of <2 days, and 110 with P {sub rot} < 1 day. Some 30 of the 178 systems exhibit two or more independent short periods within the same Kepler photometric aperture, while several have 3 or more short periods. Adaptive optics imaging and modeling of the Kepler pixel response function for a subset of our sample support the conclusion that the targets with multiple periods are highly likely to be relatively young physical binary, triple, and even quadruple M star systems. We explore in detail the one object with four incommensurate periods all less than 1.2 days, and show that two of the periods arise from one of a close pair of stars, while the other two arise from the second star, which itself is probably a visual binary. If most of these M-star systems with multiple periods turn out to be bound M stars, this could prove a valuable way discovering young hierarchical M-star systems; the same approach may also be applicable to G and K stars. The ∼5% occurrence rate of rapid rotation among the ∼3900 M star targets is consistent with spin evolution models that include an initial contraction phase followed by magnetic braking, wherein a typical M star can spend several hundred Myr before spinning down to periods longer than 2 days.

  16. Rotation dynamics of C{sub 60} molecules in a monolayer fullerene film on the WO{sub 2}/W(110) surface near the rotational phase transition

    SciTech Connect

    Bozhko, S. I.; Levchenko, E. A.; Semenov, V. N.; Bulatov, M. F.; Shvets, I. V.

    2015-05-15

    The rotation dynamics of C{sub 60} molecules in monolayer fullerene films grown on the WO{sub 2}/W(110) surface is studied by scanning tunneling microscopy. The formation of molecule clusters, which have a high libron vibration amplitude, is detected near the rotational phase transition temperature. The energy parameters that determine a change in the molecule orientation, namely, the energy difference between the nearest minima of the C{sub 60} molecule energy (30 meV) as a function of the molecule orientation and the potential barrier between them (610 meV), are determined. The results are discussed in terms of the mean-field approximation.

  17. Development of a rotating algal biofilm growth system for attached microalgae growth with in situ biomass harvest.

    PubMed

    Gross, Martin; Henry, Wesley; Michael, Clayton; Wen, Zhiyou

    2013-12-01

    This work aimed to develop a rotating algal biofilm (RAB) cultivation system that can be widely adopted by microalgae producers for easy biomass harvest. Algal cells were grown on the surface of a material rotating between nutrient-rich liquid and CO2-rich gaseous phase. Scrapping biomass from the attached surface avoided the expensive harvest operations such as centrifugation. Among various attachment materials, cotton sheet resulted in best algal growth, durability, and cost effectiveness. A lab-scale RAB system was further optimized with harvest frequency, rotation speed, and CO2 levels. The algal biomass from the RAB system had a similar water content as that in centrifuged biomass. An open pond raceway retrofitted with a pilot-scale RAB system resulted in a much higher biomass productivity when compared to a control open pond. Collectively, the research shows that the RAB system is an efficient algal culture system for easy biomass harvest with enhanced biomass productivity.

  18. Phase Rotation of Muon Beams for Producing Intense Low-Energy Muon Beams

    SciTech Connect

    Neuffer, D.; Bao, Y.; Hansen, G.

    2016-01-01

    Low-energy muon beams are useful for rare decay searches, which provide access to new physics that cannot be addressed at high-energy colliders. However, muons are produced within a broad energy spread unmatched to the low-energy required. In this paper we outline a phase rotation method to significantly increase the intensity of low-energy muons. The muons are produced from a short pulsed proton driver, and develop a time-momentum correlation in a drift space following production. A series of rf cavities is used to bunch the muons and phase-energy rotate the bunches to a momentum of around 100 MeV/c. Then another group of rf cavities is used to decelerate the muon bunches to low-energy. This obtains ~0.1 muon per 8 GeV proton, which is significantly higher than currently planned Mu2e experiments, and would enable a next generation of rare decay searches, and other intense muon beam applications.

  19. Effect of through-plane motion on left ventricular rotation: a study using slice-following harmonic phase imaging.

    PubMed

    Brotman, David; Zhang, Ziheng; Sampath, Smita

    2013-05-01

    Noninvasive quantification of regional left ventricular rotation may improve understanding of cardiac function. Current methods used to quantify rotation typically acquire data on a set of prescribed short-axis slices, neglecting effects due to through-plane myocardial motion. We combine principles of slice-following tagged imaging with harmonic phase analysis methods to account for through-plane motion in regional rotation measurements. We compare rotation and torsion measurements obtained using our method to those obtained from imaging datasets acquired without slice-following. Our results in normal volunteers demonstrate differences in the general trends of average and regional rotation-time plots in midbasal slices and the rotation versus circumferential strain loops. We observe substantial errors in measured peak average rotation of the order of 58% for basal slices (due to change in the pattern of the curve), -6.6% for midventricular slices, and -8.5% for apical slices; and an average error in base-to-apex torsion of 19% when through-plane motion is not considered. This study concludes that due to an inherent base-to-apex gradient in rotation that exists in the left ventricular, accounting for through-plane motion is critical to the accuracy of left ventricular rotation quantification.

  20. Tubing rotator system increases pumping unit tubular life

    SciTech Connect

    Graham, M. ); Brown, C. )

    1993-10-01

    Artificial lift is required on the majority of all oil wells and on some gas wells. The most common form of artificial lift is the beam pump sucker rod system. The beam pump is mechanically simple, cost effective, and has a long service life. However, the economics diminish with an increase in down time, lost production, and pulling jobs, caused by tubing failures. The most common tubing failures-split tubing-are caused by rod wear. The rods and rod boxes wear through the tubing in a narrow groove comprising about 20% of the inside diameter of the tubing. Mechanical wear from the rods and hydrostatic pressure inside the tubing causes the tubing to fail and the well is off line. Rotating the tubing string continually during pumping operations distributes rod wear over the entire inside diameter and increases tubing life. A tubing rotator system consists of surface and subsurface equipment and is powered directly by pumping unit movement is described in this paper. Application to deviated wells and in heavy oil producing wells is also discussed.

  1. The sum rule for dipolar absorptions and rotational kinetic energy of wate and some dipolar molecules in condensed phases

    NASA Astrophysics Data System (ADS)

    Ikawa, Shun-ichi; Yamazaki, Shuichi; Kimura, Masao

    1981-06-01

    Another form of the sum rule for dipolar absorptions has been derived by means of quantum statistics. The difference between this and usually used form results from a quantum effect on the molecular rotational motion. By the joint use of the two forms, average rotational kinetic energies of water molec in the liquid and solid phases and some dipolar molecules in solutions have been estimated. It has been shown that the average rotational kinetic energ larger than the value expected from the classical equipartition rule, with an increase in the hindering potential for the rotational motion of the mole The dipole moments of water molecules in liquid and solid water have been estimated. These are considerably smaller than the gas-phase value.

  2. Laser-driven rotational dynamics of gas-phase molecules: Control and applications

    NASA Astrophysics Data System (ADS)

    Ren, Xiaoming

    In this thesis, our work on developing new techniques to measure and enhance field-free molecular alignment and orientation is described. Non-resonant femtosecond laser pulses are used to align and orient rotationally-cold gas-phase molecules. The time-dependent Schrodinger equation is solved to simulate the experimental results. A single-shot kHz velocity map imaging (VMI) spectrometer is developed for characterizing 1D and 3D alignment. Stimulated by a novel metric for 3D alignment proposed by Makhija et al. [Phys. Rev. A 85,033425 (2012)], a multi-pulse scheme to improve 3D alignment is demonstrated experimentally on difluoro-iodobenzene molecules and the best field-free 3D alignment is achieved. A degenerate four wave mixing probe is developed to overcome limitations in VMI measurement; experiments on different types of molecules show good agreement with computational results. Highly aligned linear molecules are used for high harmonic generation experiments. Due to the high degree of alignment, fractional revivals, variation of revival structure with harmonic order and the shape resonance and Cooper minimum in the photoionization cross section of molecular nitrogen are all observed directly in experiment for the first time. Enhanced orientation from rotationally cold heteronuclear molecules is also demonstrated. We follow the theory developed by Zhang et al. [Phys. Rev. A 83, 043410 (2011)] and demonstrate experimentally for the first time that for rotationally cold carbon monoxide an aligning laser pulse followed by a two-color laser pulse can increase field-free orientation level by almost a factor of three compared to using just the two-color pulse.

  3. Existence results for coupled nonlinear systems approximating the rotating MHD flow over a rotating sphere near the equator

    NASA Astrophysics Data System (ADS)

    Bellout, Hamid; Vajravelu, Kuppalapalle; Van Gorder, Robert A.

    2013-02-01

    We study a coupled nonlinear system of differential equation approximating the rotating MHD flow over a rotating sphere near the equator. In particular, using the Schauder fixed point theorem, we are able to establish existence of solutions. Other results on similar systems show that the question of existence in not obvious and, hence, that the present results are useful. Indeed, the work of McLeod in the 1970s shows some nonexistence results for similar problems. From here, we are also able to discuss some of the features of the obtained solutions. The observed behaviors of the solutions agree well with the numerical simulations present in the literature.

  4. Rotating pressure measurement system using an on board calibration standard

    NASA Technical Reports Server (NTRS)

    Senyitko, Richard G.; Blumenthal, Philip Z.; Freedman, Robert J.

    1991-01-01

    A computer-controlled multichannel pressure measurement system was developed to acquire detailed flow field measurements on board the Large Low Speed Centrifugal Compressor Research Facility at the NASA Lewis Research Center. A pneumatic slip ring seal assembly is used to transfer calibration pressures to a reference standard transducer on board the compressor rotor in order to measure very low differential pressures with the high accuracy required. A unique data acquisition system was designed and built to convert the analog signal from the reference transducer to the variable frequency required by the multichannel pressure measurement system and also to provide an output for temperature control of the reference transducer. The system also monitors changes in test cell barometric pressure and rotating seal leakage and provides an on screen warning to the operator if limits are exceeded. The methods used for the selection and testing of the the reference transducer are discussed, and the data acquisition system hardware and software design are described. The calculated and experimental data for the system measurement accuracy are also presented.

  5. Confinement Regime Transition, Spontaneous Rotation and Phase Velocity Inversion of Edge Modes*

    NASA Astrophysics Data System (ADS)

    di Sanzo, C.; Coppi, B.; Landreman, M.

    2007-04-01

    The transition from the L-confinement regime to the H-regime is associated with the inversion of the phase velocity of collisional ballooningootnotetextCoppi, B., et. al., 33rd E.P.S. Plasma Conf., Paper O4.017 (2006) modes excited at the edge of the plasma column and driven by the pressure gradient. Electron-ion, ion-ion and ion-ion neutral collisions are involved in an essential way. The phase velocity inversion from the electron diamagnetic velocity direction (L-regime) to the ion's occurs when i-i collisions and i-n collisions begin to prevailootnotetextB. Coppi, MIT(LNS) Report HEP 06/12 and in Paper TH/P6-21, 2006 Intern. Fusion Energy Conf. (IAEA, Vienna) and is very similar to the one found originally,ootnotetextCoppi, B., H. Hendel, et al., Report MATT- 523 (P.P.P.L., 1967); Intern. Conf. on Phys. of Quiescent Plasmas (Frascati, 1967) in order to identify collisional electron drift modes in Q-machine experiments. The quality of confinement is associated with the effective rate of expulsion of angular momentum in the same direction as the mode phase velocity, toward the surrounding material wall, and rotation of the main plasma column resulting from recoil.ootnotetextCoppi, B., Nucl. Fusion 42, 1 (2002)*Sponsored in part by the U.S. D.O.E.

  6. Magneto-optical rotation and cross-phase modulation via coherently driven four-level atomsin a tripod configuration

    NASA Astrophysics Data System (ADS)

    Petrosyan, David; Malakyan, Yuri P.

    2004-08-01

    We study the interaction of a weak probe field, having two orthogonally polarized components, with an optically dense medium of four-level atoms in a tripod configuration. In the presence of a coherent driving laser, electromagnetically induced transparency is attained in the medium, dramatically enhancing its linear as well as nonlinear dispersion while simultaneously suppressing the probe field absorption. We present the semiclassical and fully quantum analysis of the system. We propose an experimentally feasible setup that can induce large Faraday rotation of the probe field polarization and therefore be used for ultrasensitive optical magnetometry. We then study the Kerr nonlinear coupling between the two components of the probe, demonstrating a novel regime of symmetric, extremely efficient cross-phase modulation, capable of fully entangling two single-photon pulses. This scheme may thus pave the way to photon-based quantum information applications, such as deterministic all-optical quantum computation, dense coding, and teleportation.

  7. Phase measurement system using a dithered clock

    DOEpatents

    Fairley, C.R.; Patterson, S.R.

    1991-05-28

    A phase measurement system is disclosed which measures the phase shift between two signals by dithering a clock signal and averaging a plurality of measurements of the phase differences between the two signals. 8 figures.

  8. Systems and assemblies for transferring high power laser energy through a rotating junction

    DOEpatents

    Norton, Ryan J.; McKay, Ryan P.; Fraze, Jason D.; Rinzler, Charles C.; Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

    2016-01-26

    There are provided high power laser devices and systems for transmitting a high power laser beam across a rotating assembly, including optical slip rings and optical rotational coupling assemblies. These devices can transmit the laser beam through the rotation zone in free space or within a fiber.

  9. [Effect of conservation tillage on weeds in a rotation system on the Loess Plateau of eastern Gansu, Northwest China].

    PubMed

    Zhao, Yu-xin; Lu, Jiao-yun; Yang, Hui-min

    2015-04-01

    A field study was conducted to investigate the influences of no-tillage, stubble retention and crop type on weed density, species composition and community feature in a rotation system (winter wheat-common vetch-maize) established 12 years ago on the Loess Plateau of eastern Gansu. This study showed that the weed species composition, density and community feature varied with the change of crop phases. No-tillage practice increased the weed density at maize phase, while rotation with common vetch decreased the density in the no-tillage field. Stubble retention reduced the weed density under maize phase and the lowest density was observed in the no-tillage plus stubble retention field. No-tillage practice significantly increased the weed species diversity under winter wheat phase and decreased the diversity under common vetch phase. At maize phase, a greater species diversity index was observed in the no-tillage field. These results suggested that no-tillage practice and stubble retention possibly suppress specific weeds with the presence of some crops and crop rotation is a vital way to controlling weeds in a farming system. PMID:26259467

  10. [Effect of conservation tillage on weeds in a rotation system on the Loess Plateau of eastern Gansu, Northwest China].

    PubMed

    Zhao, Yu-xin; Lu, Jiao-yun; Yang, Hui-min

    2015-04-01

    A field study was conducted to investigate the influences of no-tillage, stubble retention and crop type on weed density, species composition and community feature in a rotation system (winter wheat-common vetch-maize) established 12 years ago on the Loess Plateau of eastern Gansu. This study showed that the weed species composition, density and community feature varied with the change of crop phases. No-tillage practice increased the weed density at maize phase, while rotation with common vetch decreased the density in the no-tillage field. Stubble retention reduced the weed density under maize phase and the lowest density was observed in the no-tillage plus stubble retention field. No-tillage practice significantly increased the weed species diversity under winter wheat phase and decreased the diversity under common vetch phase. At maize phase, a greater species diversity index was observed in the no-tillage field. These results suggested that no-tillage practice and stubble retention possibly suppress specific weeds with the presence of some crops and crop rotation is a vital way to controlling weeds in a farming system.

  11. Analytical and numerical analysis of a rotational invariant D = 2 harmonic oscillator in the light of different noncommutative phase-space configurations

    NASA Astrophysics Data System (ADS)

    Abreu, Everton M. C.; Marcial, Mateus V.; Mendes, Albert C. R.; Oliveira, Wilson

    2013-11-01

    In this work we have investigated some properties of classical phase-space with symplectic structures consistent, at the classical level, with two noncommutative (NC) algebras: the Doplicher-Fredenhagen-Roberts algebraic relations and the NC approach which uses an extended Hilbert space with rotational symmetry. This extended Hilbert space includes the operators θ ij and their conjugate momentum π ij operators. In this scenario, the equations of motion for all extended phase-space coordinates with their corresponding solutions were determined and a rotational invariant NC Newton's second law was written. As an application, we treated a NC harmonic oscillator constructed in this extended Hilbert space. We have showed precisely that its solution is still periodic if and only if the ratio between the frequencies of oscillation is a rational number. We investigated, analytically and numerically, the solutions of this NC oscillator in a two-dimensional phase-space. The result led us to conclude that noncommutativity induces a stable perturbation into the commutative standard oscillator and that the rotational symmetry is not broken. Besides, we have demonstrated through the equations of motion that a zero momentum π ij originated a constant NC parameter, namely, θ ij = const., which changes the original variable characteristic of θ ij and reduces the phase-space of the system. This result shows that the momentum π ij is relevant and cannot be neglected when we have that θ ij is a coordinate of the system.

  12. Evaluation of Five Phase Digitally Controlled Rotating Field Plasma Source for Photochemical Mercury Vapor Generation Optical Emission Spectrometry.

    PubMed

    Matusiewicz, Henryk; Ślachciński, Mariusz; Pawłowski, Paweł; Portalski, Marek

    2015-01-01

    A new sensitive method for total mercury determination in reference materials using a 5-phase digitally controlled rotating field plasma source (RFP) for optical emission spectrometry (OES) was developed. A novel synergic effect of ultrasonic nebulization (USN) and ultraviolet-visible light (UV-Vis) irradiation when used in combination was exploited for efficient Hg vapor generation. UV- and Vis-based irradiation systems were studied. It was found that the most advantageous design was an ultrasonic nebulizer fitted with a 6 W mercury lamp supplying a microliter sample to a quartz oscillator, converting liquid into aerosol at the entrance of the UV spray chamber. Optimal conditions involved using a 20% v/v solution of acetic acid as the generation medium. The mercury cold vapor, favorably generated from Hg(2+) solutions by UV irradiation, was rapidly transported into a plasma source with rotating field generated within the five electrodes and detected by digitally controlled rotating field plasma optical emission spectrometry (RFP-OES). Under optimal conditions, the experimental concentration detection limit for the determination, calculated as the concentration giving a signal equal to three times the standard deviation of the blank (LOD, 3σblank criterion, peak height), was 4.1 ng mL(-1). The relative standard deviation for samples was equal to or better than 5% for liquid analysis and microsampling capability. The methodology was validated through determination of mercury in three certified reference materials (corresponding to biological and environmental samples) (NRCC DOLT-2, NRCC PACS-1, NIST 2710) using the external aqueous standard calibration techniques in acetic acid media, with satisfactory recoveries. Mercury serves as an example element to validate the capability of this approach. This is a simple, reagent-saving, cost-effective and green analytical method for mercury determination. PMID:26460362

  13. Bone resorption is affected by follicular phase length in female rotating shift workers.

    PubMed Central

    Lohstroh, Pete N; Chen, Jiangang; Ba, Jianming; Ryan, Louise M; Xu, Xiping; Overstreet, James W; Lasley, Bill L

    2003-01-01

    Stressors as subtle as night work or shift work can lead to irregular menstrual cycles, and changes in reproductive hormone profiles can adversely affect bone health. This study was conducted to determine if stresses associated with the disruption of regular work schedule can induce alterations in ovarian function which, in turn, are associated with transient bone resorption. Urine samples from 12 rotating shift workers from a textile mill in Anqing, China, were collected in 1996-1998 during pairs of sequential menstrual cycles, of which one was longer than the other (28.4 vs. 37.4 days). Longer cycles were characterized by a prolonged follicular phase. Work schedules during the luteal-follicular phase transition (LFPT) preceding each of the two cycles were evaluated. All but one of the shorter cycles were associated with regular, forward phase work shift progression during the preceding LFPT. In contrast, five longer cycles were preceded by a work shift interrupted either by an irregular shift or a number of "off days." Urinary follicle-stimulating hormone levels were reduced in the LFPT preceding longer cycles compared with those in the LFPT preceding shorter cycles. There was greater bone resorption in the follicular phase of longer cycles than in that of shorter cycles, as measured by urinary deoxypyridinoline. These data confirm reports that changes in work shift can lead to irregularity in menstrual cycle length. In addition, these data indicate that there may be an association between accelerated bone resorption in menstrual cycles and changes of regularity in work schedule during the preceding LFPT. PMID:12676625

  14. Research on motor rotational speed measurement in regenerative braking system of electric vehicle

    NASA Astrophysics Data System (ADS)

    Pan, Chaofeng; Chen, Liao; Chen, Long; Jiang, Haobin; Li, Zhongxing; Wang, Shaohua

    2016-01-01

    Rotational speed signals acquisition and processing techniques are widely used in rotational machinery. In order to realized precise and real-time control of motor drive and regenerative braking process, rotational speed measurement techniques are needed in electric vehicles. Obtaining accurate motor rotational speed signal will contribute to the regenerative braking force control steadily and realized higher energy recovery rate. This paper aims to develop a method that provides instantaneous speed information in the form of motor rotation. It addresses principles of motor rotational speed measurement in the regenerative braking systems of electric vehicle firstly. The paper then presents ideal and actual Hall position sensor signals characteristics, the relation between the motor rotational speed and the Hall position sensor signals is revealed. Finally, Hall position sensor signals conditioning and processing circuit and program for motor rotational speed measurement have been carried out based on measurement error analysis.

  15. NMR Properties of the Polar Phase of Superfluid ^3He in Anisotropic Aerogel Under Rotation

    NASA Astrophysics Data System (ADS)

    Mineev, V. P.

    2016-09-01

    The polar phase of superfluid ^3He is stable in "nematically ordered" densed aerogel. A rotating vessel with the polar superfluid can be filled either by an array of the single quantum vortices or by an array of the half-quantum vortices. It is shown that the inhomogeneous distribution of the spin part of the order parameter arising in an array of half-quantum vortices in strong enough magnetic field tilted to the average direction of aerogel strands leads to the appearance of a satellite in the NMR signal shifted in the negative direction with respect to the Larmor frequency. The satellite is absent in the case of an array of single quantum vortices which allows to distinguish these two configurations. The polar state in the anisotropic aerogel with lower density transforms at lower temperatures to the axipolar state. The array of half-quantum vortices created in the polar phase keeps its structure under transition to the axipolar state. The temperature dependence of the vortex-satellite NMR frequency is found to be slower below the transition temperature to the axipolar state.

  16. Determination of crystal violet in water by direct solid phase spectrophotometry after rotating disk sorptive extraction.

    PubMed

    Manzo, Valentina; Navarro, Orielle; Honda, Luis; Sánchez, Karen; Inés Toral, M; Richter, Pablo

    2013-03-15

    The microextraction of crystal violet (CV) from water samples into polydimethylsiloxane (PDMS) using the rotating disk sorptive extraction (RDSE) technique was performed. The extracting device was a small Teflon disk that had an embedded miniature magnetic stirring bar and a PDMS (560 μL) film attached to one side of the disk using double-sided tape. The extraction involves a preconcentration of CV into the PDMS, where the analyte is then directly quantified using solid phase spectrophotometry at 600 nm. Different chemical and extraction device-related variables were studied to achieve the best sensitivity for the determination. The optimum extraction was performed at pH 14 because under this condition, CV is transformed to the neutral and colorless species carbinol, which can be quantitatively transferred to the PDMS phase. Although the colorless species is the chemical form extracted in the PDMS, an intense violet coloration appeared in the phase because the -OH bond in the carbinol molecule is weakened through the formation of hydrogen bonds with the oxygen atoms of the PDMS, allowing the resonance between the three benzene rings to compensate for the charge deficit on the central carbon atom of the molecule. The accuracy and precision of the method were evaluated in river water samples spiked with 10 and 30 μg L(-1) of CV, yielding a relative standard deviation of 6.2% and 8.4% and a recovery of 98.4% and 99.4%, respectively. The method detection limit was 1.8 μg L(-1) and the limit of quantification was 5.4 μg L(-1), which can be decreased if the sample volume is increased.

  17. Phase ambiguity resolution for offset QPSK modulation systems

    NASA Astrophysics Data System (ADS)

    Nguyen, Tien M.

    1991-06-01

    A demodulator for Offset Quaternary Phase Shift Keyed (OQPSK) signals modulated with two words resolves eight possible combinations of phase ambiguity which may produce data error by first processing received I(sub R) and Q(sub R) data in an integrated carrier loop/symbol synchronizer using a digital Costas loop with matched filters for correcting four of eight possible phase lock errors, and then the remaining four using a phase ambiguity resolver which detects the words to not only reverse the received I(sub R) and Q(sub R) data channels, but to also invert (complement) the I(sub R) and/or Q(sub R) data, or to at least complement the I(sub R) and Q(sub R) data for systems using nontransparent codes that do not have rotation direction ambiguity.

  18. Phase ambiguity resolution for offset QPSK modulation systems

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien M. (Inventor)

    1991-01-01

    A demodulator for Offset Quaternary Phase Shift Keyed (OQPSK) signals modulated with two words resolves eight possible combinations of phase ambiguity which may produce data error by first processing received I(sub R) and Q(sub R) data in an integrated carrier loop/symbol synchronizer using a digital Costas loop with matched filters for correcting four of eight possible phase lock errors, and then the remaining four using a phase ambiguity resolver which detects the words to not only reverse the received I(sub R) and Q(sub R) data channels, but to also invert (complement) the I(sub R) and/or Q(sub R) data, or to at least complement the I(sub R) and Q(sub R) data for systems using nontransparent codes that do not have rotation direction ambiguity.

  19. Using geometric algebra to understand pattern rotations in multiple mirror optical systems

    SciTech Connect

    Hanlon, J.; Ziock, H.

    1997-05-01

    Geometric Algebra (GA) is a new formulation of Clifford Algebra that includes vector analysis without notation changes. Most applications of Ga have been in theoretical physics, but GA is also a very good analysis tool for engineering. As an example, the authors use GA to study pattern rotation in optical systems with multiple mirror reflections. The common ways to analyze pattern rotations are to use rotation matrices or optical ray trace codes, but these are often inconvenient. The authors use GA to develop a simple expression for pattern rotation that is useful for designing or tolerancing pattern rotations in a multiple mirror optical system by inspection. Pattern rotation is used in many optical engineering systems, but it is not normally covered in optical system engineering texts. Pattern rotation is important in optical systems such as: (1) the 192 beam National ignition Facility (NIF), which uses square laser beams in close packed arrays to cut costs; (2) visual optical systems, which use pattern rotation to present the image to the observer in the appropriate orientation, and (3) the UR90 unstable ring resonator, which uses pattern rotation to fill a rectangular laser gain region and provide a filled-in laser output beam.

  20. A rotating two-phase gas/liquid flow for pressure reduction in underwater plasma arc welding

    SciTech Connect

    Steinkamp, H.; Creutz, M.; Mewes, D.; Bartzsch, J.

    1994-12-31

    Plasma arc welding processes are used in off-shore industry for the construction and maintenance in the wet surrounding of underwater structures and pipelines. In greater water depth the density of the plasma gas increase because of the greater hydrostatic pressure. This causes an increase of the conductive heat losses to the wet surrounding. To keep up the energy flux to the workpiece a pressure reduction is favorable against the surrounding. To keep up the energy flux to the workpiece a pressure reduction is favorable against the surrounding. The plasma arc has to burn in a locally dry area. This requirement can be fulfilled by a rotating disc placed above the workpiece. In the gap between the lower end of the cylinder and the workpiece a rotating two-phase flow is maintained. The flow around the rotating disc is experimentally investigated. The rotating disc is placed above the surface of the workpiece which is simulated by a flat plate. Water is forced out of the cylinder due to centrifugal forces set up by the rotating disc and flat plate. The velocity distribution in the flow is measured by Laser-Doppler-Anemometry. The phase distribution in the two-phase flow in the gap is measured by local electrical probes. The static pressure in the gaseous atmosphere is reduced in comparison to the hydrostatic pressure of the surrounding water. The pressure reduction is given by the void fraction, the phase distribution and the volume flow rates of both phases in the gap as well as by the speed of revolution and the design of the disc and the work surface. Apart from the investigations on the fluid dynamics, the method to reduce the pressure was technically proved. Experiments were carried out under water with a plasma MIG welder.

  1. Gravitational radiation from rotating monopole-string systems

    SciTech Connect

    Babichev, E.; Dokuchaev, V.; Kachelriess, M.

    2005-02-15

    We study the gravitational radiation from a rotating monopole-antimonopole pair connected by a string. While at not too high frequencies the emitted gravitational spectrum is described asymptotically by P{sub n}{proportional_to}n{sup -1}, the spectrum is exponentially suppressed in the high-frequency limit, P{sub n}{proportional_to}exp(-n/n{sub cr}). Below n{sub cr}, the emitted spectrum of gravitational waves is very similar to the case of an oscillating monopole pair connected by a string, and we argue, therefore, that the spectrum found holds approximately for any moving monopole-string system. As an application, we discuss the stochastic gravitational wave background generated by monopole-antimonopole pairs connected by strings in the early Universe and gravitational wave bursts emitted at present by monopole-string networks. We confirm that advanced gravitational wave detectors have the potential to detect a signal for string tensions as small as G{mu}{approx}10{sup -13}.

  2. Rotating disk electrode system for elevated pressures and temperatures

    SciTech Connect

    Fleige, M. J.; Wiberg, G. K. H.; Arenz, M.

    2015-06-15

    We describe the development and test of an elevated pressure and temperature rotating disk electrode (RDE) system that allows measurements under well-defined mass transport conditions. As demonstrated for the oxygen reduction reaction on polycrystalline platinum (Pt) in 0.5M H{sub 2}SO{sub 4}, the setup can easily be operated in a pressure range of 1–101 bar oxygen, and temperature of 140 °C. Under such conditions, diffusion limited current densities increase by almost two orders of magnitude as compared to conventional RDE setups allowing, for example, fuel cell catalyst studies under more realistic conditions. Levich plots demonstrate that the mass transport is indeed well-defined, i.e., at low electrode potentials, the measured current densities are fully diffusion controlled, while at higher potentials, a mixed kinetic-diffusion controlled regime is observed. Therefore, the setup opens up a new field for RDE investigations under temperature and current density conditions relevant for low and high temperature proton exchange membrane fuel cells.

  3. On the Doppler effect for photons in rotating systems

    NASA Astrophysics Data System (ADS)

    Giuliani, Giuseppe

    2014-03-01

    The analysis of the Doppler effect for photons in rotating systems, studied using the Mössbauer 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 continues to be 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 should not overshadow two issues: the corpuscular theory of light, first applied to the Doppler effect for photons by Schrödinger in 1922, is by far more complete since it describes all of the features of the studied phenomena; the wave theory can only be used when the number of photons at work is statistically significant. This disregarding of basic methodological criteria may appear to be a minor fault. However, the historical development of quantum physics shows that the predominance of the wave theory of radiation, beyond its natural application domain, has hampered the reorientation toward the photon description of the underlying phenomena.

  4. Rotating dipole and quadrupole field for a multiple cathode system

    SciTech Connect

    Chang, X.; Ben-Zvi, I.; Kewisch, J.; Litvinenko, V.; Meng, W.; Pikin, A.; Ptitsyn, V.; Rao, T.; Sheehy, B.; Skarita, J.; Wang, E.; Wu, Q.; Xin, T.

    2011-03-28

    A multiple cathode system has been designed to provide the high average current polarized electron bunches for the future electron-ion collider eRHIC [1]. One of the key research topics in this design is the technique to generate a combined dipole and quadrupole rotating field at high frequency (700 kHz). This type of field is necessary for combining bunches from different cathodes to the same axis with minimum emittance growth. Our simulations and the prototype test results to achieve this will be presented. The future eRHIC project, next upgrade of EHIC, will be the first electron-heavy ion collider in the world. For polarized-electron and polarized proton collisions, it requires a polarized electron source with high average current ({approx}50 mA), short bunch ({approx}3 mm), emittance of about 20 {micro}m and energy spread of {approx}1% at 10 MeV. The state-of-art polarized electron cathode can generate average current of about more than 1 mA, but much less than 50 mA. The current is limited by the quantum efficiency, lifetime, space charge and ultra-high vacuum requirement of the polarized cathode. A possible approach to achieve the 50 mA beam is to employ multiple cathodes, such as 20 cathodes, and combine the multiple bunched beams from cathodes to the same axis. We name it as 'Gatling gun' because its operations bear similarity to a multi-barrel Gatling gun. The electron spin direction is not affected by electric field but will follow to the direction of the magnetic bending. This requires that, to preserve the spin polarization from cathode, the fixed bending field after the solenoid and the rotating bending field in combiner must be either a pair of electric bendings or a pair of magnetic bendings. We choose the scheme with a pair of magnetic bendings because it is much easier than the scheme with a pair of electric bendings at our 200 keV electron energy level.

  5. THE ROTATING MAGNETIC FIELD OSCILLATOR SYSTEM FOR CURRENT DRIVE IN THE TRANSLATION, CONFINEMENT AND SUSTAINMENT EXPERIMENT

    SciTech Connect

    S. TOBIN; ET AL

    2000-12-01

    The experimental setup and test results for the {approximately}125 MW rotating magnetic field current drive system of the Translation, Confinement and Sustainment Experiment at the University of Washington are described. The oscillator system, constructed at Los Alamos National Laboratory, drives two tank circuits (15 kV{sub peak} potential, 8.5 kA{sub peak} maximum circulating current in each tank to date) operated 90{degree} out of phase to produce a 54 G rotating magnetic field with a frequency of 163 kHz ({omega} = 1.02{sup x} 10{sup {minus}6} s{sup {minus}1}). Programmable waveform generators control ''hot deck'' totem pole drivers that are used to control the grid of 12 Machlett 8618 magnetically beamed triode tubes. This setup allows the current to be turned on or off in less than 100 ns ({approximately}6{degree}). Both tank circuits are isolated from the current source by a 1:1 air core, transmission line transformer. Each tank circuit contains two saddle coils (combined inductance of 1.6 {micro}H) and radio frequency capacitors (580 nF). Test results are presented for three conditions: no external load, a resistive external load and a plasma load. A SPICE model of the oscillator system was created. Comparisons between this model and experimental data are given.

  6. Phase Noise in Photonic Phased-Array Antenna Systems

    NASA Technical Reports Server (NTRS)

    Logan, Ronald T., Jr.; Maleki, Lute

    1998-01-01

    The total noise of a phased-array antenna system employing a photonic feed network is analyzed using a model for the individual component noise including both additive and multiplicative equivalent noise generators.

  7. Molecular disorder and translation/rotation coupling in the plastic crystal phase of hybrid perovskites

    NASA Astrophysics Data System (ADS)

    Even, J.; Carignano, M.; Katan, C.

    2016-03-01

    The complexity of hybrid organic perovskites calls for an innovative theoretical view that combines usually disconnected concepts in order to achieve a comprehensive picture: (i) the intended applications of this class of materials are currently in the realm of conventional semiconductors, which reveal the key desired properties for the design of efficient devices. (ii) The reorientational dynamics of the organic component resembles that observed in plastic crystals, therefore requiring a stochastic treatment that can be done in terms of pseudospins and rotator functions. (iii) The overall structural similarity with all inorganic perovskites suggests the use of the high temperature pseudo cubic phase as the reference platform on which further refinements can be built. In this paper we combine the existing knowledge on these three fields to define a general scenario based on which we can continue the quest towards a fundamental understanding of hybrid organic perovskites. With the introduction of group theory as the main tool to rationalize the different ideas and with the help of molecular dynamics simulations, several experimentally observed properties are naturally explained with possible suggestions for future work.

  8. Phases, phase equilibria, and phase rules in low-dimensional systems

    SciTech Connect

    Frolov, T.; Mishin, Y.

    2015-07-28

    We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality.

  9. Rotating Wolf-Rayet stars in a post RSG/LBV phase. An evolutionary channel towards long-duration GRBs?

    NASA Astrophysics Data System (ADS)

    Gräfener, G.; Vink, J. S.; Harries, T. J.; Langer, N.

    2012-11-01

    Context. Wolf-Rayet (WR) stars with fast rotating cores are thought to be the direct progenitors of long-duration gamma-ray bursts (LGRBs). A well accepted evolutionary channel towards LGRBs is chemically-homogeneous evolution at low metallicities, which completely avoids a red supergiant (RSG), or luminous blue variable (LBV) phase. On the other hand, strong absorption features with velocities of several hundred km s-1 have been found in some LGRB afterglow spectra (GRB 020813 and GRB 021004), which have been attributed to dense circumstellar (CS) material that has been ejected in a previous RSG or LBV phase, and is interacting with a fast WR-type stellar wind. Aims: Here we investigate the properties of Galactic WR stars and their environment to identify similar evolutionary channels that may lead to the formation of LGRBs. Methods: We compile available information on the spectropolarimetric properties of 29 WR stars, the presence of CS ejecta for 172 WR stars, and the CS velocities in the environment of 34 WR stars in the Galaxy. We use linear line-depolarization as an indicator of rotation, nebular morphology as an indicator of stellar ejecta, and velocity patterns in UV absorption features as an indicator of increased velocities in the CS environment. Results: Based on previous nebular classifications, we determine an incidence rate of ~23% of WR stars with "possible ejecta nebulae" in the Galaxy. We find that this group of objects dominates the population of WR stars with spectropolarimetric signatures of rotation, while WR stars without such nebulae only rarely show indications of rotation. This confirms the correlation between rotation and CS ejecta from our previous work. The corresponding objects are most likely in an early stage after a preceding RSG or LBV phase, and have not yet lost their angular momenta due to the strong mass-loss in the WR phase. From their photometric periods we estimate rotation parameters in the range ω = νrot/νcrit = 0

  10. Unitary transformations purely based on geometric phases of two spins with Ising interaction in a rotating magnetic field

    SciTech Connect

    Shi Yu

    2010-06-15

    We consider how to obtain a nontrivial two-qubit unitary transformation purely based on geometric phases of two spin-1/2 's with Ising-like interaction in a magnetic field with a static z-component and a rotating xy-component. This is an interesting problem both for the purpose of measuring the geometric phases and in quantum computing applications. In previous approach, coupling of one of the qubit with the rotating component of field is ignored. By considering the exact two-spin geometric phases, we find that a nontrivial two-spin unitary transformation purely based on Berry phases can be obtained by using two consecutive cycles with opposite directions of the magnetic field and opposite signs of the interaction constant. In the nonadiabatic case, starting with a certain initial state, a cycle in the projected space of rays and thus Aharonov-Anandan phase can be achieved. The two-cycle scheme cancels the total phases, hence any unknown initial state evolves back to itself without a phase factor.

  11. Coherent quasielastic neutron scattering study of the rotational dynamics of C sub 60 in the orientationally disordered phase

    SciTech Connect

    Neumann, D.A.; Copley, J.R.D.; Cappelletti, R.L.; Kamitakahara, W.A.; Lindstrom, R.M.; Creegan, K.M.; Cox, D.M.; Romanow, W.J.; Coustel, N.; McCauley, J.P. Jr.; Maliszewskyj, N.C.; Fischer, J.E.; Smith, A.B. III Department of Physics and Astronomy and Condensed Matter and Surface Sciences Program, Ohio University, Athens, Ohio 45701 Department of Physics, University of Maryland, College Park, Maryland 20742 Exxon Research and Engineering Company, Annandale, New Jersey 08801 Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania 19104 Materials Science Department, University of Pennsylvania, Philadelphia, Pennsylvania 19104 Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United St

    1991-12-30

    Coherent quasielastic neutron scattering has been used to investigate the character of the rotational dynamics in the high-temperature solid phase of C{sub 60}. The observed scattering can be described by a model in which each molecule undergoes rotational diffusion which is uncorrelated with the motions of adjacent molecules. The rotational diffusion constant {ital D}{sub {ital R}} is (1.4{plus minus}0.4){times}10{sup 10} s{sup {minus}1} at 260 K and (2.8{plus minus}0.8){times}10{sup 10} s{sup {minus}1} at 520 K. The temperature dependence of {ital D}{sub {ital R}} is consistent with a thermally activated process having an activation energy of 35{plus minus}15 meV.

  12. Characterizing the rotational irregularities of the Vela pulsar from 21 yr of phase-coherent timing

    NASA Astrophysics Data System (ADS)

    Shannon, R. M.; Lentati, L. T.; Kerr, M.; Johnston, S.; Hobbs, G.; Manchester, R. N.

    2016-07-01

    Pulsars show two classes of rotational irregularities that can be used to understand neutron-star interiors and magnetospheres: glitches and timing noise. Here we present an analysis of the Vela pulsar spanning nearly 21 yr of observation and including eight glitches. We identify the relative pulse number of all of the observations between glitches, with the only pulse-number ambiguities existing over glitch events. We use the phase coherence of the timing solution to simultaneously model the timing noise and glitches in a Bayesian framework, allowing us to select preferred models for both. We find the glitches can be described using only permanent and transient changes in spin frequency, i.e. no step changes in frequency derivative. For all of the glitches, we only need two exponentially decaying changes in spin frequency to model the transient components. In contrast to previous studies, we find that the dominant transient components decay on a common ≈1300 d time-scale, and that a larger fraction (≳25 per cent) of glitch amplitudes are associated with these transient components. We also detect shorter-duration transient components of ≈25 d, as previously observed, but are limited in sensitivity to events with shorter durations by the cadence of our observations. The timing noise is well described by a steep power-law process that is independent of the glitches and subdominant to the glitch recovery. The braking index is constrained to be <8 with 95 per cent confidence. This methodology can be used to robustly measure the properties of glitches and timing noise in other pulsars.

  13. Geology of the Phase II System

    SciTech Connect

    Laney, R.; Laughlin, A. William

    1980-11-19

    This is a report on the analysis of EE-2 cuttings and thin sections, geologic characterization of the Phase II system, comparison with Phase 1, and geologic speculations and recommendations concerning Phase II. The EE-2 litholog has been included in the pocket.

  14. Architecture and life support systems for a rotating space habitat

    NASA Astrophysics Data System (ADS)

    Misra, Gaurav

    Life Support Systems are critical to sustain human habitation of space over long time periods. As orbiting space habitats become operational in the future, support systems such as atmo-sphere, food, water etc. will play a very pivotal role in sustaining life. To design a long-duration space habitat, it's important to consider the full gamut of human experience of the environment. Long-term viability depends on much more than just the structural or life support efficiency. A space habitat isn't just a machine; it's a life experience. To be viable, it needs to keep the inhabitants satisfied with their condition. This paper provides conceptual research on several key factors that influence the growth and sustainability of humans in a space habitat. Apart from the main life support system parameters, the architecture (both interior and exterior) of the habitat will play a crucial role in influencing the liveability in the space habitat. In order to ensure the best possible liveability for the inhabitants, a truncated (half cut) torus is proposed as the shape of the habitat. This structure rotating at an optimum rpm will en-sure 1g pseudo gravity to the inhabitants. The truncated torus design has several advantages over other proposed shapes such as a cylinder or a sphere. The design provides minimal grav-ity variation (delta g) in the living area, since its flat outer pole ensures a constant gravity. The design is superior in economy of structural and atmospheric mass. Interior architecture of the habitat addresses the total built environment, drawing from diverse disciplines includ-ing physiology, psychology, and sociology. Furthermore, factors such as line of sight, natural sunlight and overhead clearance have been discussed in the interior architecture. Substantial radiation shielding is also required in order to prevent harmful cosmic radiations and solar flares from causing damage to inhabitants. Regolith shielding of 10 tons per meter square is proposed for the

  15. Method and means of correcting for a shift in the center of rotation of a rotating fan beam CT system

    SciTech Connect

    Gulberg, G.T.; Crawford, C.R.

    1989-03-14

    In a fan beam computed tomographic system having a detector system for taking a plurality of projections at a plurality of angles, each projection defining a plurality of projection bins, the computed tomographic system having a given center of rotation which is shifted from the midline of the fan by a shift distance which varies as a function of projection angle, a method compensating for the shift in performing the computed tomographic reconstruction comprising the steps of, producing a weighting function for each projection bin in each projection set which is dependent on the detector geometry and the magnitude of the shift for the respective projections, weighting the information in each projection bin with its associated weighting function to produce corrected projection sets, convolving the corrected projection sets with a filter function to produce convolved corrected projection sets, setting up a coordinate system in pixelized space taking into account the shift and its variance as a function of projection angle, and back projecting the convolved corrected projection sets in to the pixelized space using the coordinate system to produce a CT image corrected for the variable shift. The patent also describes an improved apparatus for compensating for the shift in performing the computed tomographic reconstruction. Finally, the patent describes a set of geometric parameters including a distance between the apex of the fan and the detector, a distance between the apex of the fan and the center of rotation of the detector, a position of a point on the detector defined by the midline of the fan, and a center of rotation shifted with respect to the projection as a function of projection angle.

  16. Design and Simulation of a Rotating Aperture & Vacuum System for Neutron Imaging

    SciTech Connect

    Fitsos, P; Hall, J; Rusnak, B; Shen, S

    2006-02-27

    The development of a high-energy (10Mev) neutron imaging system at Lawrence Livermore National Laboratory (LLNL) depends on a precision engineered rotating aperture and vacuum system for generating neutrons that are used for imaging dense objects. This subsystem is part of a larger system which includes a linear accelerator that creates a deuteron beam, a scintillator detector, imaging optics and a high resolution CCD camera. The rotating aperture vacuum system has been successfully simulated and tested. Results show the feasibility of the design and point toward ways to improve the design by minimizing the rotating aperture gap.

  17. SLC Interferometer System and Phase Distribution Upgrades

    SciTech Connect

    Akre, Ron; /SLAC

    2011-08-26

    Many of the components used in the Stanford Linear Collider (SLC) phasing system date back 30 years to the construction of SLAC. At the start of SLC the phase reference system was upgraded with many of the original components remaining. The R.F. drive system phase stability requirements became tighter with operation and optimization of the SLC. This paper describes analysis done on the R.F. drive system and interferometer system during the 1996 run and down time, modifications to the systems during the 1996-97 down time, and the improvements in stability from the modifications.

  18. Beyond the diffraction limit of optical/IR interferometers. II. Stellar parameters of rotating stars from differential phases

    NASA Astrophysics Data System (ADS)

    Hadjara, M.; Domiciano de Souza, A.; Vakili, F.; Jankov, S.; Millour, F.; Meilland, A.; Khorrami, Z.; Chelli, A.; Baffa, C.; Hofmann, K.-H.; Lagarde, S.; Robbe-Dubois, S.

    2014-09-01

    Context. As previously demonstrated on Achernar, one can derive the angular radius, rotational velocity, axis tilt, and orientation of a fast-rotating star from the differential phases obtained by spectrally resolved long baseline interferometry using earth-rotation synthesis. Aims: We applied this method on a small sample of stars for different spectral types and classes, in order to generalize the technique to other rotating stars across the H-R diagram and determine their fundamental parameters. Methods: We used differential phase data from the AMBER/VLTI instrument obtained prior to refurbishing its spectrometer in 2010. With the exception of Fomalhaut, which has been observed in the medium-resolution mode of AMBER (λ/δλ ≈ 1500), our three other targets, Achernar, Altair, and δ Aquilae offered high-resolution (λ/δλ ≈ 12 000) spectro-interferometric data around the Brγ absorption line in K band. These data were used to constrain the input parameters of an analytical, still realistic model to interpret the observations with a systematic approach for the error budget analysis in order to robustly conclude on the physics of our 4 targets. We applied the super resolution provided by differential phases φdiff to measure the size (equatorial radius Req and angular diameter ⌀eq), the equatorial rotation velocity (Veq), the inclination angle (i), and the rotation axis position angle (PArot) of 4 fast-rotating stars: Achernar, Altair, δ Aquilae, and Fomalhaut. The stellar parameters of the targets were constrained using a semi-analytical algorithm dedicated to fast rotators SCIROCCO. Results: The derived parameters for each star were Req = 11.2 ± 0.5 R⊙, Veqsini = 290 ± 17 km s-1, PArot = 35.4° ± 1.4°, for Achernar; Req = 2.0 ± 0.2 R⊙, Veqsini = 226 ± 34 km s-1, PArot = -65.5° ± 5.5°, for Altair; Req = 2.2 ± 0.3 R⊙, Veqsini = 74 ± 35 km s-1, PArot = -101.2° ± 14°, for δ Aquilae; and Req = 1.8 ± 0.2 R⊙, Veqsini = 93 ± 16 km s-1

  19. Note: Sub-Kelvin refrigeration with dry-coolers on a rotating system

    NASA Astrophysics Data System (ADS)

    Oguri, S.; Ishitsuka, H.; Choi, J.; Kawai, M.; Tajima, O.

    2014-08-01

    We developed a cryogenic system on a rotating table that achieves sub-Kelvin conditions. The cryogenic system consists of a helium sorption cooler and a pulse tube cooler in a cryostat mounted on a rotating table. Two rotary-joint connectors for electricity and helium gas circulation enable the coolers to be operated and maintained with ease. We performed cool-down tests under a condition of continuous rotation at 20 rpm. We obtained a temperature of 0.23 K with a holding time of more than 24 h, thus complying with catalog specifications. We monitored the system's performance for four weeks; two weeks with and without rotation. A few-percent difference in conditions was observed between these two states. Most applications can tolerate such a slight difference. The technology developed is useful for various scientific applications requiring sub-Kelvin conditions on rotating platforms.

  20. Note: Sub-Kelvin refrigeration with dry-coolers on a rotating system.

    PubMed

    Oguri, S; Ishitsuka, H; Choi, J; Kawai, M; Tajima, O

    2014-08-01

    We developed a cryogenic system on a rotating table that achieves sub-Kelvin conditions. The cryogenic system consists of a helium sorption cooler and a pulse tube cooler in a cryostat mounted on a rotating table. Two rotary-joint connectors for electricity and helium gas circulation enable the coolers to be operated and maintained with ease. We performed cool-down tests under a condition of continuous rotation at 20 rpm. We obtained a temperature of 0.23 K with a holding time of more than 24 h, thus complying with catalog specifications. We monitored the system's performance for four weeks; two weeks with and without rotation. A few-percent difference in conditions was observed between these two states. Most applications can tolerate such a slight difference. The technology developed is useful for various scientific applications requiring sub-Kelvin conditions on rotating platforms. PMID:25173326

  1. Information Display System for Atypical Flight Phase

    NASA Technical Reports Server (NTRS)

    Statler, Irving C. (Inventor); Ferryman, Thomas A. (Inventor); Amidan, Brett G. (Inventor); Whitney, Paul D. (Inventor); White, Amanda M. (Inventor); Willse, Alan R. (Inventor); Cooley, Scott K. (Inventor); Jay, Joseph Griffith (Inventor); Lawrence, Robert E. (Inventor); Mosbrucker, Chris J. (Inventor); Rosenthal, Loren J. (Inventor); Lynch, Robert E. (Inventor); Chidester, Thomas R. (Inventor); Prothero, Gary L. (Inventor); Andrei, Adi (Inventor); Romanowski, Timothy P. (Inventor); Robin, Daniel E. (Inventor); Prothero, Jason W. (Inventor)

    2007-01-01

    Method and system for displaying information on one or more aircraft flights, where at least one flight is determined to have at least one atypical flight phase according to specified criteria. A flight parameter trace for an atypical phase is displayed and compared graphically with a group of traces, for the corresponding flight phase and corresponding flight parameter, for flights that do not manifest atypicality in that phase.

  2. Cycle slipping in phase synchronization systems

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Huang, Lin

    2007-02-01

    Cycle slipping is a characteristically nonlinear phenomenon in phase synchronization systems, which is highly dependent of the initial state of the system. Slipping a cycle means that the phase error is increased to such an extent that the generator to be synchronized slips one complete cycle with respect to the input phase. In this Letter, a linear matrix inequality (LMI) based approach is proposed and the estimation of the number of cycles which slips a solution of the system is obtained by solving a quasi-convex optimization problem of LMI. Applications to phase locked loops demonstrate the validity of the proposed approach.

  3. A vision-based dynamic rotational angle measurement system for large civil structures.

    PubMed

    Lee, Jong-Jae; Ho, Hoai-Nam; Lee, Jong-Han

    2012-01-01

    In this paper, we propose a vision-based rotational angle measurement system for large-scale civil structures. Despite the fact that during the last decade several rotation angle measurement systems were introduced, they however often required complex and expensive equipment. Therefore, alternative effective solutions with high resolution are in great demand. The proposed system consists of commercial PCs, commercial camcorders, low-cost frame grabbers, and a wireless LAN router. The calculation of rotation angle is obtained by using image processing techniques with pre-measured calibration parameters. Several laboratory tests were conducted to verify the performance of the proposed system. Compared with the commercial rotation angle measurement, the results of the system showed very good agreement with an error of less than 1.0% in all test cases. Furthermore, several tests were conducted on the five-story modal testing tower with a hybrid mass damper to experimentally verify the feasibility of the proposed system.

  4. A vision-based dynamic rotational angle measurement system for large civil structures.

    PubMed

    Lee, Jong-Jae; Ho, Hoai-Nam; Lee, Jong-Han

    2012-01-01

    In this paper, we propose a vision-based rotational angle measurement system for large-scale civil structures. Despite the fact that during the last decade several rotation angle measurement systems were introduced, they however often required complex and expensive equipment. Therefore, alternative effective solutions with high resolution are in great demand. The proposed system consists of commercial PCs, commercial camcorders, low-cost frame grabbers, and a wireless LAN router. The calculation of rotation angle is obtained by using image processing techniques with pre-measured calibration parameters. Several laboratory tests were conducted to verify the performance of the proposed system. Compared with the commercial rotation angle measurement, the results of the system showed very good agreement with an error of less than 1.0% in all test cases. Furthermore, several tests were conducted on the five-story modal testing tower with a hybrid mass damper to experimentally verify the feasibility of the proposed system. PMID:22969348

  5. Design and Realization of Rotating Machinery Conditions Monitoring System Based on Labview

    NASA Astrophysics Data System (ADS)

    Fan, Qiyuan

    Nonlinear dynamic analysis of rotating machinery system has always been the hot spot of the rotational dynamics research. This article sets up a rotating machinery condition monitoring system to realize the measurement of system dynamic characteristic parameters based on NI(National Instruments) virtual instruments technology. The measurement of vibration signal of rotating machinery system is achieved by using NI company general data acquisition module of NI company. Meanwhile, by analyzing and processing the acquired data using Labview 2012, the dynamic characteristics, such as .the speed of the rotating machinery system, the axis trajectory, spectrum parameters, are attained. The measurement results show that the rotating machinery condition monitoring system based on Labview is easy to operate, easy to realize the function extension and maintenance, and that it can be used in the industrial engineering projects with rotation characteristics. Labview as the development tools used by virtual instrument function, is very powerful data acquisition software products support is one of the features of it, so using Labview programming and data acquisition is simple and convenient [1].

  6. A stable high-speed rotational transmission system based on nanotubes

    SciTech Connect

    Cai, Kun; Yin, Hang; Wei, Ning; Chen, Zhen; Shi, Jiao

    2015-01-12

    A stable rotational transmission system is designed with a single-walled carbon nanotube (SWCNT)-based motor and double-walled carbon nanotubes (DWCNTs)-based bearing. The system response is investigated using molecular dynamics (MD) simulation. It is found that the rotating motor can actuate the rotation of the inner tube in bearing because of the attraction between the two adjacent coaxial ends of motor and rotor (the inner tube in bearing). To have a stable nanostructure, each carbon atom on the adjacent ends of motor and rotor is bonded with a hydrogen atom. To obtain a stable high-speed rotational transmission system, both an armchair and a zigzag model are used in MD simulation. In each model, the motor with different diameters and rotational speeds is employed to examine the rotational transmission of corresponding DWCNTs. It is demonstrated that the long range van der Waals interaction between the adjacent ends of motor and rotor leads to a stable configuration of the adjacent ends, and further leads to a stable rotation of rotor when driven by a high-speed motor. As compared with the armchair model, the rotor in the zigzag model could reach a stable rotation mode much easier.

  7. Dynamical Stability and Long-term Evolution of Rotating Stellar Systems

    NASA Astrophysics Data System (ADS)

    Varri, Anna L.; Vesperini, E.; McMillan, S. L. W.; Bertin, G.

    2011-05-01

    We present the first results of an extensive survey of N-body simulations designed to investigate the dynamical stability and the long-term evolution of two new families of self-consistent stellar dynamical models, characterized by the presence of internal rotation. The first family extends the well-known King models to the case of axisymmetric systems flattened by solid-body rotation while the second family is characterized by differential rotation. The equilibrium configurations thus obtained can be described in terms of two dimensionless parameters, which measure the concentration and the amount of rotation, respectively. Slowly rotating configurations are found to be dynamically stable and we followed their long-term evolution, in order to evaluate the interplay between collisional relaxation and angular momentum transport. We also studied the stability of rapidly rotating models, which are characterized by the presence of a toroidal core embedded in an otherwise quasi-spherical configuration. In both cases, a description in terms of the radial and global properties, such as the ratio between the ordered kinetic energy and the gravitational energy of the system, is provided. Because the role of angular momentum in the process of cluster formation is only partly understood, we also undertook a preliminary investigation of the violent relaxation of simple systems initially characterized by approximate solid-body rotation. The properties of the final equilibrium configurations thus obtained are compared with those of the above-described family of differentially rotating models.

  8. Theoretical analysis of a rotating two-phase detonation in liquid rocket motors.

    NASA Technical Reports Server (NTRS)

    Shen, P. I.-W.; Adamson, T. C., Jr.

    1972-01-01

    A nonlinear analysis to study tangential mode shock instabilities in a thin annular chamber is carried out by employing a one dimensional two phase detonation wave as a reaction model. It is assumed that phase change and reaction take place only within the wave, which is treated as a discontinuity. The annulus is unrolled and the flow is considered as two dimensional with the coordinate system fixed on the wave front. Between waves, the flow is assumed to be isentropic with no interaction between droplets and burned gases. Jump conditions across the wave are solved for two phase flow. The average pressure along the injection plate is related to the design chamber pressure by the use of overall conservation equations. The wave strength is written in terms of the design parameters of the chamber. The results compare favorably with existing experiments. Finally, the effects of drop size on the wave strength are discussed and a simple criterion which sets the lower limit of validity for this strong wave analysis, is presented.

  9. Attitude Heading Reference System Using MEMS Inertial Sensors with Dual-Axis Rotation

    PubMed Central

    Kang, Li; Ye, Lingyun; Song, Kaichen; Zhou, Yang

    2014-01-01

    This paper proposes a low cost and small size attitude and heading reference system based on MEMS inertial sensors. A dual-axis rotation structure with a proper rotary scheme according to the design principles is applied in the system to compensate for the attitude and heading drift caused by the large gyroscope biases. An optimization algorithm is applied to compensate for the installation angle error between the body frame and the rotation table's frame. Simulations and experiments are carried out to evaluate the performance of the AHRS. The results show that the proper rotation could significantly reduce the attitude and heading drifts. Moreover, the new AHRS is not affected by magnetic interference. After the rotation, the attitude and heading are almost just oscillating in a range. The attitude error is about 3° and the heading error is less than 3° which are at least 5 times better than the non-rotation condition. PMID:25268911

  10. Acoustic rotation control

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Croonquist, A. P.; Wang, T. G. (Inventor)

    1983-01-01

    A system is described for acoustically controlled rotation of a levitated object, which avoids deformation of a levitated liquid object. Acoustic waves of the same wavelength are directed along perpendicular directions across the object, and with the relative phases of the acoustic waves repeatedly switched so that one wave alternately leads and lags the other by 90 deg. The amount of torque for rotating the object, and the direction of rotation, are controlled by controlling the proportion of time one wave leads the other and selecting which wave leads the other most of the time.

  11. Phase synchronization in time-delay systems.

    PubMed

    Senthilkumar, D V; Lakshmanan, M; Kurths, J

    2006-09-01

    Though the notion of phase synchronization has been well studied in chaotic dynamical systems without delay, it has not been realized yet in chaotic time-delay systems exhibiting non-phase-coherent hyperchaotic attractors. In this paper we report identification of phase synchronization in coupled time-delay systems exhibiting hyperchaotic attractor. We show that there is a transition from nonsynchronized behavior to phase and then to generalized synchronization as a function of coupling strength. These transitions are characterized by recurrence quantification analysis, by phase differences based on a transformation of the attractors, and also by the changes in the Lyapunov exponents. We have found these transitions in coupled piecewise linear and in Mackey-Glass time-delay systems.

  12. EFFECTS OF ROTATION ON STOCHASTICITY OF GRAVITATIONAL WAVES IN THE NONLINEAR PHASE OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Kotake, Kei; Iwakami-Nakano, Wakana; Ohnishi, Naofumi

    2011-08-01

    By performing three-dimensional (3D) simulations that demonstrate the neutrino-driven core-collapse supernovae aided by the standing accretion shock instability (SASI), we study how the spiral modes of the SASI can impact the properties of the gravitational-wave (GW) emission. To see the effects of rotation in the nonlinear postbounce phase, we give a uniform rotation on the flow advecting from the outer boundary of the iron core, the specific angular momentum of which is assumed to agree with recent stellar evolution models. We compute fifteen 3D models in which the initial angular momentum and the input neutrino luminosities from the protoneutron star are changed in a systematic manner. By performing a ray-tracing analysis, we accurately estimate the GW amplitudes generated by anisotropic neutrino emission. Our results show that the gravitational waveforms from neutrinos in models that include rotation exhibit a common feature; otherwise, they vary much more stochastically in the absence of rotation. The breaking of the stochasticity stems from the excess of the neutrino emission parallel to the spin axis. This is because the compression of matter is more enhanced in the vicinity of the equatorial plane due to the growth of the spiral SASI modes, leading to the formation of the spiral flows circulating around the spin axis with higher temperatures. We point out that recently proposed future space interferometers like Fabry-Perot-type DECIGO would permit the detection of these signals for a Galactic supernova.

  13. Determination and visualization of rotational ambiguity in four-component systems.

    PubMed

    Golshan, Azadeh; Maeder, Marcel; Abdollahi, Hamid

    2013-09-24

    One of the main problems that limit the use of model-free analysis methods for the resolution of multivariate data is that usually there is rotational ambiguity in the result. While methods for the complete definition of rotational ambiguity for two- and three-component systems have been published recently, the comprehensive and general resolution of rotational ambiguity for four-component systems has eluded chemists for several decades. We have developed an extension of self-modelling curve resolution for a mixture of four-components. The performance of the method was verified by applying it to resolve simulated and real data sets. PMID:24016578

  14. Hybrid laser-beam-shaping system for rotatable dual beams with long depth of focus

    NASA Astrophysics Data System (ADS)

    Chou, Fu-Lung; Chen, Cheng-Huan; Lin, Yu-Chung; Lin, Mao-Chi

    2016-10-01

    A laser processing system consisting of two diffractive elements and one refractive element is proposed enabling a Gaussian laser beam to be transformed into two beams with a depth of focus of up to 150 µm and focal spot smaller than 5 µm. For specific laser processing, the two beams are rotatable when the beam-splitting diffractive element is rotated. The overall system is versatile for laser cutting and drilling.

  15. Hybrid laser-beam-shaping system for rotatable dual beams with long depth of focus

    NASA Astrophysics Data System (ADS)

    Chou, Fu-Lung; Chen, Cheng-Huan; Lin, Yu-Chung; Lin, Mao-Chi

    2016-08-01

    A laser processing system consisting of two diffractive elements and one refractive element is proposed enabling a Gaussian laser beam to be transformed into two beams with a depth of focus of up to 150 µm and focal spot smaller than 5 µm. For specific laser processing, the two beams are rotatable when the beam-splitting diffractive element is rotated. The overall system is versatile for laser cutting and drilling.

  16. Controllable nanoscale rotating actuator system based on carbon nanotube and graphene

    NASA Astrophysics Data System (ADS)

    Huang, Jianzhang; Han, Qiang

    2016-04-01

    A controllable nanoscale rotating actuator system consisting of a double carbon nanotube and graphene driven by a temperature gradient is proposed, and its rotating dynamics performance and driving mechanism are investigated through molecular dynamics simulations. The outer tube exhibits stable pure rotation with certain orientation under temperature gradient and the steady rotational speed rises as the temperature gradient increases. It reveals that the driving torque is caused by the difference of atomic van der Waals potentials due to the temperature gradient and geometrical features of carbon nanotube. A theoretical model for driving torque is established based on lattice dynamics theory and its predicted results agree well with molecular dynamics simulations. Further discussion is taken according to the theoretical model. The work in this study would be a guide for design and application of controllable nanoscale rotating devices based on carbon nanotubes and graphene.

  17. Phase-Insensitive Ultrasonic Testing System

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.

    1995-01-01

    Ultrasonic testing system developed for use in revealing hidden disbonds at rough, inaccessible interfaces between layers of material. Includes array of small piezoelectric transducers, receiving outputs electronically processed individually and combined in such way as to make system phase-insensitive, overcoming limitations imposed by phase-sensitivity. Development of present ultrasonic system and phase-insensitive-array technique which based motivated by need to detect disbonds under conditions of bondline inhibitor, liner, and fuel at ends of segments of solid rocket motor of space shuttle. Here, liner-to-fuel bondline very rough with respect to ultrasonic wavelength.

  18. The geometric phase in nonlinear dissipative systems

    SciTech Connect

    Ning, C.Z.; Haken, H. )

    1992-10-30

    In this paper, the authors review the recent progress made in generalizing the concept of the geometric phase to nonlinear dissipative systems. The authors first illustrate the usual form of the parallel transport law with an elementary example of the parallel shift of a line on the complex plane. Important results about the non-adiabatical geometric (Aharonov and Anandan or AA) phase [sup 18] for the Schrodinger equations are reviewed in order to make a comparison with results for dissipative systems. The authors show that a geometric phase can be defined for dissipative systems with the cyclic attractors. Systems undergoing the Hopf bifurcation with a continuous symmetry are shown to possess such cyclic attractors. Examples from laser physics are discussed to exhibit the applicability of our formalism and the widespread existence of the geometric phase in dissipative systems.

  19. Accuracy of gantry rotation time of less than 300 ms for modern MDCT systems.

    PubMed

    Fukuda, Atsushi; Lin, Pei-Jan Paul; Matsubara, Kosuke; Miyati, Tosiaki

    2015-01-01

    The accuracy of gantry rotation times of less than 300 ms has been assessed for two "state-of-the art" MDCT systems. The rotation time was measured at selected nominal rotation times (275 and 280 ms) with a solid-state detector; Unfors Xi probe. The detector was positioned on the inner bottom of the gantry bore. Because a pair of two successive radiation peaks is necessary for determination of the rotation time, the radiation detection was performed with the helical scan mode of operation. Upon completion of the data acquisition, we determined the peak times with the Unfors Xi View software program to obtain the rotation time. The means and standard deviations of the measured rotation times were 275.3 ± 0.5 and 285.1 ± 0.4 ms, respectively. The inaccuracy of the rotation time was approximately 5 ms at most, which was comparable to that previously reported for slower rotation times.

  20. Flow of Fluid and Particle Assemblages in Rotating Systems

    NASA Technical Reports Server (NTRS)

    Kizito, John; Hiltner, David; Niederhaus, Charles; Kleis, Stanley; Hudson, Ed; Gonda, Steve

    2004-01-01

    NASA-designed bioreactors have been highly successful in growing three-dimensional tissue structures in a low shear environment both on earth and in space. The goal of the present study is to characterize the fluid flow environment within the HFB-S bioreactor and determine the spatial distribution of particles that mimic cellular tissue structures. The results will be used to obtain optimal operating conditions of rotation rates and media perfusehnfuse rates which are required for cell culture growth protocols. Two types of experiments have been performed so far. First, we have performed laser florescent dye visualization of the perfusion loop to determine the mixing times within the chamber. The second type of experiments involved particles which represent cellular tissue to determine the spatial distribution with the chamber. From these experiments we established that mixing times were largely dependant on the speed ratio and sign of the difference between the spinner and the dome. The shortest mixing times occurred when the spinner rotates faster than the dome and longest mixing times occurs with no relative motion between the dome and spinner. Also, we have determined the spatial and temporal distribution of particle assemblages within the chamber.

  1. Critical-Point Description of the Transition from Vibrational to Rotational Regimes in the Pairing Phase

    SciTech Connect

    Clark, R.M.; Macchiavelli, A.O.; Fortunato, L.; Kruecken, R.

    2006-01-27

    An approximate solution at the critical point of the pairing transition from harmonic vibration to deformed rotation in gauge space is found by analytic solution of the collective pairing Hamiltonian. The eigenvalues are expressed in terms of the zeros of Bessel functions of integer order. The results are compared to the pairing bands based on the Pb isotopes.

  2. Evolutionary models of rotating dense stellar systems: challenges in software and hardware

    NASA Astrophysics Data System (ADS)

    Fiestas, Jose

    2016-02-01

    We present evolutionary models of rotating self-gravitating systems (e.g. globular clusters, galaxy cores). These models are characterized by the presence of initial axisymmetry due to rotation. Central black hole seeds are alternatively included in our models, and black hole growth due to consumption of stellar matter is simulated until the central potential dominates the kinematics in the core. Goal is to study the long-term evolution (~ Gyr) of relaxed dense stellar systems, which deviate from spherical symmetry, their morphology and final kinematics. With this purpose, we developed a 2D Fokker-Planck analytical code, which results we confirm by detailed N-Body techniques, applying a high performance code, developed for GPU machines. We compare our models to available observations of galactic rotating globular clusters, and conclude that initial rotation modifies significantly the shape and lifetime of these systems, and can not be neglected in studying the evolution of globular clusters, and the galaxy itself.

  3. Nature of the middle phase in three-phase micellar systems at phase behavior optimal salinity

    SciTech Connect

    Rosen, M.J.; Li, Z.P.

    1984-02-01

    Analysis of the middle phase of two heptane- surfactant-2-phenoxyethanol (cosurfactant)-brine systems at the point of phase behavior optimal salinity shows that surfactant and cosurfactant concentration gradients and a density gradient develop upon standing. Surfactant and cosurfactant concentrations and density all increase with depth below the upper (heptane/middle phase) interface. The nonhomogeneity depends upon the presence of condensed phases of different nature at both interfaces of the middle phase, as shown by its disappearance when the heptane phase is removed. The phenomenon is reversible, as shown by the reappearance of the gradients upon centrifugation of the middle phase, in the absence of heptane and brine phases, at sufficiently high speed. 16 references.

  4. Coordinate transformation between rotating and inertial systems under the constant two-way speed of light

    NASA Astrophysics Data System (ADS)

    Choi, Yang-Ho

    2016-09-01

    An observation system consists of the world lines of rest observers in the system. Recently a coordinate transformation between an isotropic and a rotating observation system has been presented which was derived through a relativistic circular approach based on the Lorentz transformation. It was formulated such that the relative speeds between the two systems are the same, but the two-way speed of light is not constant in the rotating observation system. The constancy of the two-way speed of light in inertial frames has been known to be experimentally verified. This paper presents the transformation that holds the constancy in the rotating system as well. Though the rotating system is in motion with acceleration, it can be regarded as locally inertial. Thus, in the limit, a transformation into a rotating system should be reduced to a transformation into an inertial systems. The transformation presented is consistent with the one between inertial systems so that the latter can be derived from the former in the limit. Moreover it allows us to theoretically analyze the generalized Sagnac effect, which involves rectilinear motion as well as circular motion. The theoretical analysis corresponds to the experimental results.

  5. Phase Transitions in Model Active Systems

    NASA Astrophysics Data System (ADS)

    Redner, Gabriel S.

    The amazing collective behaviors of active systems such as bird flocks, schools of fish, and colonies of microorganisms have long amazed scientists and laypeople alike. Understanding the physics of such systems is challenging due to their far-from-equilibrium dynamics, as well as the extreme diversity in their ingredients, relevant time- and length-scales, and emergent phenomenology. To make progress, one can categorize active systems by the symmetries of their constituent particles, as well as how activity is expressed. In this work, we examine two categories of active systems, and explore their phase behavior in detail. First, we study systems of self-propelled spherical particles moving in two dimensions. Despite the absence of an aligning interaction, this system displays complex emergent dynamics, including phase separation into a dense active solid and dilute gas. Using simulations and analytic modeling, we quantify the phase diagram and separation kinetics. We show that this nonequilibrium phase transition is analogous to an equilibrium vapor-liquid system, with binodal and spinodal curves and a critical point. We also characterize the dense active solid phase, a unique material which exhibits the structural signatures of a crystalline solid near the crystal-hexatic transition point, as well as anomalous dynamics including superdiffusive motion on intermediate timescales. We also explore the role of interparticle attraction in this system. We demonstrate that attraction drastically changes the phase diagram, which contains two distinct phase-separated regions and is reentrant as a function of propulsion speed. We interpret this complex situation with a simple kinetic model, which builds from the observed microdynamics of individual particles to a full description of the macroscopic phase behavior. We also study active nematics, liquid crystals driven out of equilibrium by energy-dissipating active stresses. The equilibrium nematic state is unstable in these

  6. Phononic Phase Conjugation in an Optomechanical System

    NASA Astrophysics Data System (ADS)

    Buchmann, Lukas; Wright, Ewan; Meystre, Pierre

    2013-05-01

    We study theoretically the phase conjugation of a phononic field in an optomechanical system with two mechanical modes coupled to a common optical field. Phase conjugation becomes the dominant process for an appropriate choice of driving field parameters, and he effective coupling coefficients between phonon modes can result in amplification and entanglement, phase-conjugation or a mixture thereof. We discuss surprising consequences of mechanical phase-conjugation that could lead to the preparation of mechanical states with negative temperature, the improvement of quantum memories and the study of the quantum-classical transition. Supported by DARPA ORCHID program.

  7. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems.

    PubMed

    Bu, Rongyan; Lu, Jianwei; Ren, Tao; Liu, Bo; Li, Xiaokun; Cong, Rihuan

    2015-01-01

    Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N) mineralization. The quantity and quality of particulate organic matter (POM) and potentially mineralizable-N (PMN) contents were measured in soils from 16 paired rice-rapeseed (RR)/cotton-rapeseed (CR) rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile), intermediate (25th and 75th percentiles), and high (90th percentile) levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C) and N (POM-N) contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN) contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively) than CR rotations (45.6% and 19.5%, respectively). Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials) in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils. PMID:26647157

  8. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems

    PubMed Central

    Bu, Rongyan; Lu, Jianwei; Ren, Tao; Liu, Bo; Li, Xiaokun; Cong, Rihuan

    2015-01-01

    Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N) mineralization. The quantity and quality of particulate organic matter (POM) and potentially mineralizable-N (PMN) contents were measured in soils from 16 paired rice-rapeseed (RR)/cotton-rapeseed (CR) rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile), intermediate (25th and 75th percentiles), and high (90th percentile) levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C) and N (POM-N) contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN) contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively) than CR rotations (45.6% and 19.5%, respectively). Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials) in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils. PMID:26647157

  9. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems.

    PubMed

    Bu, Rongyan; Lu, Jianwei; Ren, Tao; Liu, Bo; Li, Xiaokun; Cong, Rihuan

    2015-01-01

    Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N) mineralization. The quantity and quality of particulate organic matter (POM) and potentially mineralizable-N (PMN) contents were measured in soils from 16 paired rice-rapeseed (RR)/cotton-rapeseed (CR) rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile), intermediate (25th and 75th percentiles), and high (90th percentile) levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C) and N (POM-N) contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN) contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively) than CR rotations (45.6% and 19.5%, respectively). Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials) in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils.

  10. An interferometer based phase control system

    NASA Technical Reports Server (NTRS)

    Ott, J. H.; Rice, J. S.

    1980-01-01

    An interferometer based phase control system for focusing and pointing the solar power satellite (SPS) power beam is discussed. The system is ground based and closed loop. One receiving antenna is required on Earth. A conventional uplink data channel transmits an 8 bit phase error correction back to the SPS for sequential calibration of each power module. Beam pointing resolution is better than 140 meters at the rectenna.

  11. Interferometer-based phase control system

    SciTech Connect

    Ott, J.H.; Rice, J.S.

    1980-01-01

    An interferometer-based phase control system for focusing and pointing the SPS power beam is discussed. The system is ground based and closed loop. One receiving antenna is required on earth. A conventional uplink data channel transmits an 8-bit phase error correction back to the SPS for sequential calibration of each power module. Beam pointing resolution is better than 140 meters at the Rectenna. 1 ref.

  12. Locomotion gaits of a rotating cylinder pair

    NASA Astrophysics Data System (ADS)

    van Rees, Wim M.; Novati, Guido; Koumoutsakos, Petros; Mahadevan, L.

    2015-11-01

    Using 2D numerical simulations of the Navier-Stokes equations, we demonstrate that a simple pair of rotating cylinders can display a range of locomotion patterns of biological and engineering interest. Steadily counter-rotating the cylinders causes the pair to move akin to a vortex dipole for low rotation rates, but as the rotational velocity is increased the direction of motion reverses. Unsteady rotations lead to different locomotion gaits that resemble jellyfish (for in-phase rotations) and undulating swimmers (for out-of-phase rotations). The small number of parameters for this simple system allows us to systematically map the phase space of these gaits, and allows us to understand the underlying physical mechanisms using a minimal model with implications for biological locomotion and engineered analogs.

  13. A three-dimensional phase field model coupled with lattice kinetics solver for modeling crystal growth in furnaces with accelerated crucible rotation and traveling magnetic field

    SciTech Connect

    Lin, Guang; Bao, Jie; Xu, Zhijie

    2014-11-01

    In this study, which builds on other related work, we present a new three-dimensional numerical model for crystal growth in a vertical solidification system. This model accounts for buoyancy, accelerated crucible rotation technique (ACRT), and traveling magnetic field (TMF) induced convective flow and their effect on crystal growth and the chemical component's transport process. The evolution of the crystal growth interface is simulated using the phase field method. A semi-implicit lattice kinetics solver based on the Boltzmann equation is employed to model the unsteady incompressible flow. A one-way coupled concentration transport model is used to simulate the component fraction variation in both the liquid and solid phases, which can be used to check the quality of the crystal growth.

  14. Density distribution of a rotating plasma in Tornado magnetic confinement systems

    SciTech Connect

    Kuznetsov, V.M.; Pakhomov, A.B.; Rusakov, A.I.

    1984-12-01

    The density distribution of a rotating plasma in a Tornado magnetic confinement system is calculated under the assumption that the plasma rotates at constant angular velocity throughout the region bounded by the separatrix. The component of the centrifugal inertial force parallel to the magnetic force lines is shown to pinch the plasma toward the equatorial plane of the system. The density distribution depends on the ratio v/T of the plasma drift velocity and temperature. The experimentally measured density distribution can be used to determine v/T and thus to analyze the rotating plasma. If v is known for the rotating plasma then T can be calculated from v, and vice versa.

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

    SciTech Connect

    Waszczak, Adam; Chang, Chan-Kao; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke; Ofek, Eran O.; Laher, Russ; Surace, Jason; Masci, Frank; Helou, George; Levitan, David; Prince, Thomas A.; Kulkarni, Shrinivas

    2015-09-15

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

  16. Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; Surace, Jason; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke; Helou, George; Prince, Thomas A.; Kulkarni, Shrinivas

    2015-09-01

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

  17. Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; Surace, Jason; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke; Helou, George; Prince, Thomas A.; Kulkarni, Shrinivas

    2015-09-01

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

  18. Reflection-induced linear polarization rotation and phase modulation between orthogonal waves for refractive index variation measurement.

    PubMed

    Twu, Ruey-Ching; Wang, Jhao-Sheng

    2016-04-01

    An optical phase interrogation is proposed to study reflection-induced linear polarization rotation in a common-path homodyne interferometer. This optical methodology can also be applied to the measurement of the refractive index variation of a liquid solution. The performance of the refractive index sensing structure is discussed theoretically, and the experimental results demonstrated a very good ability based on the proposed schemes. Compared with a conventional common-path heterodyne interferometer, the proposed homodyne interferometer with only a single channel reduced the usage of optic elements. PMID:27192320

  19. Bench-Top Impedance Measurements for a Rotatable Copper Collimator for the LHC Phase II Collimation Upgrade

    SciTech Connect

    Smith, Jeffrey Claiborne; Bane, Karl; Doyle, Eric; Keller, Lew; Lundgren, Steve; Markiewicz, Tom; Ng, Cho-Kuen; Xiao, Liling; /SLAC

    2010-08-26

    Simulations have been performed in Omega3P to study both trapped modes and impedance contributions of a rotatable collimator for the LHC phase II collimation upgrade. Bench-top stretched coil probe impedance methods are also being implemented for measurements on prototype components to directly measure the low frequency impedance contributions. The collimator design also calls for a RF contact interface at both jaw ends with contact resistance much less than a milliohm in order to limit transverse impedance. DC resistance measurements in a custom built test chamber have been performed to test the performance of this interface.

  20. Nitrogen, tillage, and crop rotation effects on nitrous oxide emissions from irrigated cropping systems.

    PubMed

    Halvorson, Ardell D; Del Grosso, Stephen J; Reule, Curtis A

    2008-01-01

    We evaluated the effects of irrigated crop management practices on nitrous oxide (N(2)O) emissions from soil. Emissions were monitored from several irrigated cropping systems receiving N fertilizer rates ranging from 0 to 246 kg N ha(-1) during the 2005 and 2006 growing seasons. Cropping systems included conventional-till (CT) continuous corn (Zea mays L.), no-till (NT) continuous corn, NT corn-dry bean (Phaseolus vulgaris L.) (NT-CDb), and NT corn-barley (Hordeum distichon L.) (NT-CB). In 2005, half the N was subsurface band applied as urea-ammonium nitrate (UAN) at planting to all corn plots, with the rest of the N applied surface broadcast as a polymer-coated urea (PCU) in mid-June. The entire N rate was applied as UAN at barley and dry bean planting in the NT-CB and NT-CDb plots in 2005. All plots were in corn in 2006, with PCU being applied at half the N rate at corn emergence and a second N application as dry urea in mid-June followed by irrigation, both banded on the soil surface in the corn row. Nitrous oxide fluxes were measured during the growing season using static, vented chambers (1-3 times wk(-1)) and a gas chromatograph analyzer. Linear increases in N(2)O emissions were observed with increasing N-fertilizer rate, but emission amounts varied with growing season. Growing season N(2)O emissions were greater from the NT-CDb system during the corn phase of the rotation than from the other cropping systems. Crop rotation and N rate had more effect than tillage system on N(2)O emissions. Nitrous oxide emissions from N application ranged from 0.30 to 0.75% of N applied. Spikes in N(2)O emissions after N fertilizer application were greater with UAN and urea than with PCU fertilizer. The PCU showed potential for reducing N(2)O emissions from irrigated cropping systems. PMID:18574163

  1. Nitrogen, tillage, and crop rotation effects on nitrous oxide emissions from irrigated cropping systems.

    PubMed

    Halvorson, Ardell D; Del Grosso, Stephen J; Reule, Curtis A

    2008-01-01

    We evaluated the effects of irrigated crop management practices on nitrous oxide (N(2)O) emissions from soil. Emissions were monitored from several irrigated cropping systems receiving N fertilizer rates ranging from 0 to 246 kg N ha(-1) during the 2005 and 2006 growing seasons. Cropping systems included conventional-till (CT) continuous corn (Zea mays L.), no-till (NT) continuous corn, NT corn-dry bean (Phaseolus vulgaris L.) (NT-CDb), and NT corn-barley (Hordeum distichon L.) (NT-CB). In 2005, half the N was subsurface band applied as urea-ammonium nitrate (UAN) at planting to all corn plots, with the rest of the N applied surface broadcast as a polymer-coated urea (PCU) in mid-June. The entire N rate was applied as UAN at barley and dry bean planting in the NT-CB and NT-CDb plots in 2005. All plots were in corn in 2006, with PCU being applied at half the N rate at corn emergence and a second N application as dry urea in mid-June followed by irrigation, both banded on the soil surface in the corn row. Nitrous oxide fluxes were measured during the growing season using static, vented chambers (1-3 times wk(-1)) and a gas chromatograph analyzer. Linear increases in N(2)O emissions were observed with increasing N-fertilizer rate, but emission amounts varied with growing season. Growing season N(2)O emissions were greater from the NT-CDb system during the corn phase of the rotation than from the other cropping systems. Crop rotation and N rate had more effect than tillage system on N(2)O emissions. Nitrous oxide emissions from N application ranged from 0.30 to 0.75% of N applied. Spikes in N(2)O emissions after N fertilizer application were greater with UAN and urea than with PCU fertilizer. The PCU showed potential for reducing N(2)O emissions from irrigated cropping systems.

  2. Ground beetle (Coleoptera: Carabidae) assemblages in conventional and diversified crop rotation systems.

    PubMed

    O'Rourke, Megan E; Liebman, Matt; Rice, Marlin E

    2008-02-01

    Ground beetles (Coleoptera: Carabidae) are important in agro-ecosystems as generalist predators of invertebrate pests and weed seeds and as prey for larger animals. However, it is not well understood how cropping systems affect ground beetles. Over a 2-yr period, carabids were monitored two times per month using pitfall traps in a conventional chemical input, 2-yr, corn/soybean rotation system and a low input, 4-yr, corn/soybean/triticale-alfalfa/alfalfa rotation system. Carabid assemblages were largely dominated by a few species across all cropping treatments with Poecilus chalcites Say comprising >70% of pitfall catches in both years of study. Overall carabid activity density and species richness were higher in the low input, 4-yr rotation compared with the conventionally managed, 2-yr rotation. There were greater differences in the temporal activity density and species richness of carabids among crops than within corn and soybean treatments managed with different agrichemical inputs and soil disturbance regimes. Detrended correspondence analysis showed strong yearly variation in carabid assemblages in all cropping treatments. The increase in carabid activity density and species richness observed in the 4-yr crop rotation highlights the potential benefits of diverse crop habitats for carabids and the possibility for managing natural enemies by manipulating crop rotations.

  3. Block Copolymer Modified Epoxy Amine System for Reactive Rotational Molding: Structures, Properties and Processability

    NASA Astrophysics Data System (ADS)

    Lecocq, Eva; Nony, Fabien; Tcharkhtchi, Abbas; Gérard, Jean-François

    2011-05-01

    Poly(styrene-butadiene-methylmethacrylate) (SBM) and poly(methylmethacrylate-butyle-acrylate-methylmethacrylate) (MAM) triblock copolymers have been dissolved in liquid DGEBA epoxy resin which is subsequently polymerized by meta-xylene diamine (MXDA) or Jeffamine EDR-148. A chemorheology study of these formulations by plate-plate rheology and by thermal analysis has allowed to conclude that the addition of these copolymer blocks improve the reactive rotational moulding processability without affecting the processing time. Indeed, it prevents the pooling of the formulation at the bottom of the mould and a too rapid build up of resin viscosity of these thermosetting systems. The morphology of the cured blends examined by scanning electron microscopy (SEM) shows an increase of fracture surface area and thereby a potential increase of the toughness with the modification of epoxy system. Dynamic mechanical spectroscopy (DMA) and opalescence of final material show that the block PMMA, initially miscible, is likely to induce phase separation from the epoxy-amine matrix. Thereby, the poor compatibilisation between the toughener and the matrix has a detrimental effect on the tensile mechanical properties. The compatibilisation has to be increased to improve in synergy the processability and the final properties of these block copolymer modified formulations. First attempts could be by adapting the length and ratio of each block.

  4. Phase diagram of degenerate exciton systems.

    PubMed

    Lai, C W; Zoch, J; Gossard, A C; Chemla, D S

    2004-01-23

    Degenerate exciton systems have been produced in quasi-two-dimensional confined areas in semiconductor coupled quantum well structures. We observed contractions of clouds containing tens of thousands of excitons within areas as small as (10 micron)2 near 10 kelvin. The spatial and energy distributions of optically active excitons were determined by measuring photoluminescence as a function of temperature and laser excitation and were used as thermodynamic quantities to construct the phase diagram of the exciton system, which demonstrates the existence of distinct phases. Understanding the formation mechanisms of these degenerate exciton systems can open new opportunities for the realization of Bose-Einstein condensation in the solid state.

  5. Two-component phase-averaged turbulence statistics downstream of a rotating spoked-wheel wake generator

    NASA Technical Reports Server (NTRS)

    O'Brien, J. E.; Capp, S. P.

    1989-01-01

    Flow-field measurements of unsteady turbulent flow downstream of a rotating spoked-wheel wake generator were performed in a short-duration light-piston tunnel, and the instantaneous-velocity data were phase averaged based on a signal synchronized with the bar-passing frequency. Mean axial velocities were found to agree well with those obtained from measurements behind a stationary cylinder and to be independent of both Reynolds and bar-passing Strouhal numbers. Reynolds stresses were found to be consistent with related cylinder-wake measurements, but were significantly higher than corresponding measurements obtained in large-scale research turbomachines. Phase-averaged triple velocity correlations were calculated from the digital velocity records, revealing the sign and the magnitude of skewness in the velocity probability density distributions for the two components.

  6. Two-component phase-averaged turbulence statistics downstream of a rotating spoked-wheel wake generator

    NASA Astrophysics Data System (ADS)

    O'Brien, J. E.; Capp, S. P.

    1989-10-01

    Flow-field measurements of unsteady turbulent flow downstream of a rotating spoked-wheel wake generator were performed in a short-duration light-piston tunnel, and the instantaneous-velocity data were phase averaged based on a signal synchronized with the bar-passing frequency. Mean axial velocities were found to agree well with those obtained from measurements behind a stationary cylinder and to be independent of both Reynolds and bar-passing Strouhal numbers. Reynolds stresses were found to be consistent with related cylinder-wake measurements, but were significantly higher than corresponding measurements obtained in large-scale research turbomachines. Phase-averaged triple velocity correlations were calculated from the digital velocity records, revealing the sign and the magnitude of skewness in the velocity probability density distributions for the two components.

  7. An interferometer-based phase control system

    NASA Technical Reports Server (NTRS)

    Ott, J. H.; Rice, J. S.

    1981-01-01

    A system for focusing and pointing the SPS power beam is discussed. The system is ground based and closed loop. One receiving antenna is required on earth. A conventional uplinked data channel transmits an 8-bit phase error correction back to the SPS for sequential calibration of each power module. Beam pointing resolution is better than 140 meters at the rectenna.

  8. An interferometer-based phase control system

    NASA Technical Reports Server (NTRS)

    Ott, J. H.; Rice, J. S.

    1980-01-01

    A system for focusing and pointing the SPS power beam is discussed. The system is ground based and closed loop. One receiving antenna is required on Earth. A conventional uplink data channel transmits an 8-bit phase error correlation back to the SPS for sequential calibration of each power module. Beam pointing resolution is better than 140 meters at the Rectenna.

  9. Nucleation in finite topological systems during continuous metastable quantum phase transitions.

    PubMed

    Fialko, Oleksandr; Delattre, Marie-Coralie; Brand, Joachim; Kolovsky, Andrey R

    2012-06-22

    Finite topological quantum systems can undergo continuous metastable quantum phase transitions to change their topological nature. Here we show how to nucleate the transition between ring currents and dark soliton states in a toroidally trapped Bose-Einstein condensate. An adiabatic passage to wind and unwind its phase is achieved by explicit global breaking of the rotational symmetry. This could be realized with current experimental technology.

  10. Evaluation of soil quality indicators in paddy soils under different crop rotation systems

    NASA Astrophysics Data System (ADS)

    Nadimi-Goki, Mandana; Bini, Claudio; Haefele, Stephan; Abooei, Monireh

    2013-04-01

    Evaluation of soil quality indicators in paddy soils under different crop rotation systems Soil quality, by definition, reflects the capacity to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Soil quality assessment is an essential issue in soil management for agriculture and natural resource protection. This study was conducted to detect the effects of four crop rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) on soil quality indicators (soil moisture, porosity, bulk density, water-filled pore space, pH, extractable P, CEC, OC, OM, microbial respiration, active carbon) in paddy soils of Verona area, Northern Italy. Four adjacent plots which managed almost similarly, over five years were selected. Surface soil samples were collected from each four rotation systems in four times, during growing season. Each soil sample was a composite of sub-samples taken from 3 points within 350 m2 of agricultural land. A total of 48 samples were air-dried and passed through 2mm sieve, for some chemical, biological, and physical measurements. Statistical analysis was done using SPSS. Statistical results revealed that frequency distribution of most data was normal. The lowest CV% was related to pH. Analysis of variance (ANOVA) and comparison test showed that there are significant differences in soil quality indicators among crop rotation systems and sampling times. Results of multivariable regression analysis revealed that soil respiration had positively correlation coefficient with soil organic matter, soil moisture and cation exchange capacity. Overall results indicated that the rice rotation with legumes such as bean and soybean improved soil quality over a long time in comparison to rice-fallow rotation, and this is reflected in rice yield. Keywords: Soil quality, Crop Rotation System, Paddy Soils, Italy

  11. System and Method for Obtaining Simultaneous Levitation and Rotation of a Ferromagnetic Object

    NASA Astrophysics Data System (ADS)

    Banerjee, Subrata; Sarkar, Mrinal Kanti; Ghosh, Arnab

    2016-06-01

    In this work a practical demonstration for simultaneous levitation and rotation for a ferromagnetic cylindrical object is presented. A hollow steel cylinder has been arranged to remain suspended stably under I-core electromagnet utilizing dc attraction type levitation principle and then arranged to rotate the levitated object around 1000 rpm speed based on eddy current based energy meter principle. Since the object is to be rotating during levitated condition the device will be frictionless, energy-efficient and robust. This technology may be applied to frictionless energy meter, wind turbine, machine tool applications, precision instruments and many other devices where easy energy-efficient stable rotation will be required. The cascade lead compensation control scheme has been applied for stabilization of unstable levitation system. The proposed device is successfully tested in the laboratory and experimental results have been produced.

  12. Local Anesthetics in the Gas-Phase the Rotational Spectrum of Butamben and Isobutamben

    NASA Astrophysics Data System (ADS)

    Vallejo-López, Montserrat; Ecija, Patricia; Caminati, Walther; Grabow, Jens-Uwe; Lesarri, Alberto; Cocinero, Emilio J.

    2016-06-01

    Benzocaine (BZ), butamben (BTN) and isobutamben (BTI) are local anesthetics characterized by a hydrophilic head and a lipophilic aliphatic tail linked by an aminobenzoate group. Previous rotational work on BZ (H2N-C6H4-COO-Et) showed that its ethyl aliphatic tail may adopt either in-plane (trans) or out of plane (gauche) conformations, with a low interconversion barrier below 50 cm-1. Here we extend the rotational study to BTN and BTI, isolated in a supersonic jet expansion and vaporized either by heating or UV ps-laser ablation methods. Both molecules share a 14 heavy-atoms skeleton, differing in their butyl (-(CH2)3-CH3) or isobutyl (-CH2-CH(CH3)2) four-carbon tail. We detected a single conformer for BTN and two conformers for BTI. The two molecules do not adopt an all-trans carbon skeleton. Conversely, the β-ethyl carbon in BTN is gauche. For BTI the β-carbon may be either trans or gauche. The microwave spectrum covered the cm- (BTN, BTI, 6-18 GHz) and mm-wave (BTW, 50-75 GHz) frequency ranges.In all the cases, rotational and centrifugal distortion constants as well as the diagonal elements of the 14N nuclear quadrupole coupling tensor were accurate determined and compared to the theoretical results (ab initio and DFT). No transitions belonging to configurations predicted as higher minima of the PES were found, pointing out that conformational interconversions may take place in the jet. A. Lesarri, S. T. Shipman, G. G. Brown, L. Alvarez-Valtierra, R. D. Suenram, B. H. Pate, Int. Symp. Mol. Spectrosc., 2008, Comm. RH07. E. Aguado, A. Longarte, E. Alejandro, J. A. Fernández, F. Castaño, J. Phys. Chem. A, 2006, 110, 6010.

  13. A Method for Achieving Constant Rotation Rates in a Micro-Orthogonal Linkage System

    SciTech Connect

    Dickey, F.M.; Holswade, S.C.; Romero, L.A.

    1999-05-12

    Silicon micromachine designs include engines that consist of orthog- onally oriented linear comb drive actuators mechanically connected to a rotating gear. These gears are as small as 50 {micro}m in diameter and can be driven at rotation rates exceeding 300,000 rpm. Generally, these en- gines will run with non-uniform rotation rates if the drive signals are not properly designed and maintained over a range of system parameters. We present a method for producing constant rotation rates in a micro-engine driven by an orthogonal linkage system. We show that provided the val- ues of certain masses, springs, damping factors, and lever arms are in the right proportions, the system behaves as though it were symmetrical. We will refer to systems built in this way as being quasi-symmetrical. We show that if a system is built quasi-symmetrically , then it is possible to achieve constant rotation rates even if one does not know the form of the friction function, or the value of the friction. We analyze this case in some detail.

  14. Ka-Band Phased Array System Characterization

    NASA Technical Reports Server (NTRS)

    Acosta, R.; Johnson, S.; Sands, O.; Lambert, K.

    2001-01-01

    Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rates several orders of magnitude higher than currently offered with reflector-based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA-based links. Short spacing of radiating elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2 pi phase errors can add to Inter Symbol Interference (ISI), phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased-array antennas when used in a high data rate modulation link. The tests and evaluations described here uncover the interaction between the electrical characteristics of a PAA and the BER performance of a communication link.

  15. An automatic method for determining the centre of rotation of a mechanically scanned reflection UCT system.

    PubMed

    Jago, J R

    1994-12-01

    A method will be described for determining the centre of rotation of a mechanically scanned reflection ultrasound computed tomography system. It is based on the principle of obtaining opposing images of a test object containing many point targets. The method is automatic in the sense that the centre of rotation is calculated by a computer without the need for an operator to make direct measurements on the mechanical system. For the particular reflection UCT system described here, the centre of rotation is obtained in 3-5 min with a repeatability (+/-2 SD) of +/-0.3 mm. Ways in which even higher accuracy can be obtained are discussed. The basic principle of the method is applicable to any concentric imaging system for which a good approximation to an ideal point target can be produced.

  16. Electrostatic 512kV Rotator/Oscillator Propulsion System

    SciTech Connect

    Maker, David

    2007-01-30

    The purpose of this paper is to show that by replacing the standard General Relativity (GR) gravity metric term with goo with a new one E and M goo in the Kerr metric you obtain some interesting propulsion effects. To prove that this replacement is plausible however one has to First show how it fits into the context of the equivalence principle and conventional quantum mechanics; here in the form of a new Dirac equation. In that regard this new Dirac equation has the advantage that it puts the general covariance at the beginning of the Dirac equation derivation, instead of in the covariant (gauge) derivatives; having the effect of reducing the number of free parameters from 18 to 1 and thus streamlining the Standard Model (SM) of particle physics. This very successful new Dirac equation has a square root of that new E and M gii in front of its kinetic term. This new E and M gii should then allow replacement the conventional gravity goo at least in the context of quantum mechanics. The implication then is that the gravity term in the Schwarzchild and in the Kerr rotational metric(s) can be replaced as well with this new E and M metric term in the context of E and M experiments with the Maxwell equations applying in the small field limit. We solve for this time increment dt in this new Kerr metric using the quadratic formula given the presence of dt2 and dt terms in that metric and show how we can measure its effect in an experiment. This dt would create an impulse/m that can be used for propulsion.

  17. SYNCHROTRON RADIO FREQUENCY PHASE CONTROL SYSTEM

    DOEpatents

    Plotkin, M.; Raka, E.C.; Snyder, H.S.

    1963-05-01

    A system for canceling varying phase changes introduced by connecting cables and control equipment in an alternating gradient synchrotron is presented. In a specific synchrotron embodiment twelve spaced accelerating stations for the proton bunches are utilized. In order to ensure that the protons receive their boost or kick at the exact instant necessary it is necessary to compensate for phase changes occurring in the r-f circuitry over the wide range of frequencies dictated by the accelerated velocities of the proton bunches. A constant beat frequency is utilized to transfer the r-f control signals through the cables and control equipment to render the phase shift constant and readily compensable. (AEC)

  18. The CentO satellite confers translational and rotational phasing on cenH3 nucleosomes in rice centromeres

    PubMed Central

    Zhang, Tao; Talbert, Paul B.; Zhang, Wenli; Wu, Yufeng; Yang, Zujun; Henikoff, Jorja G.; Henikoff, Steven; Jiang, Jiming

    2013-01-01

    Plant and animal centromeres comprise megabases of highly repeated satellite sequences, yet centromere function can be specified epigenetically on single-copy DNA by the presence of nucleosomes containing a centromere-specific variant of histone H3 (cenH3). We determined the positions of cenH3 nucleosomes in rice (Oryza sativa), which has centromeres composed of both the 155-bp CentO satellite repeat and single-copy non-CentO sequences. We find that cenH3 nucleosomes protect 90–100 bp of DNA from micrococcal nuclease digestion, sufficient for only a single wrap of DNA around the cenH3 nucleosome core. cenH3 nucleosomes are translationally phased with 155-bp periodicity on CentO repeats, but not on non-CentO sequences. CentO repeats have an ∼10-bp periodicity in WW dinucleotides and in micrococcal nuclease cleavage, providing evidence for rotational phasing of cenH3 nucleosomes on CentO and suggesting that satellites evolve for translational and rotational stabilization of centromeric nucleosomes. PMID:24191062

  19. VizieR Online Data Catalog: Rotating Wolf-Rayet stars in post RSG/LBV phase (Graefener+, 2012)

    NASA Astrophysics Data System (ADS)

    Graefener, G.; Vink, J. S.; Harries, T. J.; Langer, N.

    2013-01-01

    Wolf-Rayet (WR) stars with fast rotating cores are thought to be the direct progenitors of long-duration gamma-ray bursts (LGRBs). A well accepted evolutionary channel towards LGRBs is chemically-homogeneous evolution at low metallicities, which completely avoids a red supergiant (RSG), or luminous blue variable (LBV) phase. On the other hand, strong absorption features with velocities of several hundred km/s have been found in some LGRB afterglow spectra (GRB 020813 and GRB 021004), which have been attributed to dense circumstellar (CS) material that has been ejected in a previous RSG or LBV phase, and is interacting with a fast WR-type stellar wind. Here we investigate the properties of Galactic WR stars and their environment to identify similar evolutionary channels that may lead to the formation of LGRBs. We compile available information on the spectropolarimetric properties of 29 WR stars, the presence of CS ejecta for 172 WR stars, and the CS velocities in the environment of 34 WR stars in the Galaxy. We use linear line-depolarization as an indicator of rotation, nebular morphology as an indicator of stellar ejecta, and velocity patterns in UV absorption features as an indicator of increased velocities in the CS environment. (2 data files).

  20. Radio Frequency Trap for Containment of Plasmas in Antimatter Propulsion Systems Using Rotating Wall Electric Fields

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III (Inventor); Martin, James Joseph (Inventor); Lewis, Raymond A. (Inventor)

    2003-01-01

    A containment apparatus for containing a cloud of charged particles comprises a cylindrical vacuum chamber having a longitudinal axis. Within the vacuum chamber is a containment region. A magnetic field is aligned with the longitudinal axis of the vacuum chamber. The magnetic field is time invariant and uniform in strength over the containment region. An electric field is also aligned with the longitudinal axis of the vacuum chamber and the magnetic field. The electric field is time invariant, and forms a potential well over the containment region. One or more means are disposed around the cloud of particles for inducing a rotating electric field internal to the vacuum chamber. The rotating electric field imparts energy to the charged particles within the containment region and compress the cloud of particles. The means disposed around the outer surface of the vacuum chamber for inducing a rotating electric field are four or more segments forming a segmented ring, the segments conforming to the outer surface of the vacuum chamber. Each of the segments is energized by a separate alternating voltage. The sum of the voltages imposed on each segment establishes the rotating field. When four segments form a ring, the rotating field is obtained by a signal generator applying a sinusoidal signal phase delayed by 90,180 and 270 degrees in sequence to the four segments.

  1. Post-Transition State Dynamics in Gas Phase Reactivity: Importance of Bifurcations and Rotational Activation.

    PubMed

    Martín-Sómer, Ana; Yáñez, Manuel; Hase, William L; Gaigeot, Marie-Pierre; Spezia, Riccardo

    2016-03-01

    Beyond the established use of thermodynamic vs kinetic control to explain chemical reaction selectivity, the concept of bifurcations on a potential energy surface (PES) is proving to be of pivotal importance with regard to selectivity. In this article, we studied by means of post-transition state (TS) direct dynamics simulations the effect that vibrational and rotational excitation at the TS may have on selectivity on a bifurcating PES. With this aim, we studied the post-TS unimolecular reactivity of the [Ca(formamide)](2+) ion, for which Coulomb explosion and neutral loss reactions compete. The PES exhibits different kinds of nonintrinsic reaction coordinate (IRC) dynamics, among them PES bifurcations, which direct the trajectories to multiple reaction paths after passing the TS. Direct dynamics simulations were used to distinguish between the bifurcation non-IRC dynamics and non-IRC dynamics arising from atomistic motions directing the trajectories away from the IRC. Overall, we corroborated the idea that kinetic selectivity often does not reduce to a simple choice between paths with different barrier heights and instead dynamical behavior after passing the TS may be crucial. Importantly, rotational excitation may play a pivotal role on the reaction selectivity favoring nonthermodynamic products.

  2. Diversifying crop rotations with pulses enhances system productivity.

    PubMed

    Gan, Yantai; Hamel, Chantal; O'Donovan, John T; Cutforth, Herb; Zentner, Robert P; Campbell, Con A; Niu, Yining; Poppy, Lee

    2015-01-01

    Agriculture in rainfed dry areas is often challenged by inadequate water and nutrient supplies. Summerfallowing has been used to conserve rainwater and promote the release of nitrogen via the N mineralization of soil organic matter. However, summerfallowing leaves land without any crops planted for one entire growing season, creating lost production opportunity. Additionally, summerfallowing has serious environmental consequences. It is unknown whether alternative systems can be developed to retain the beneficial features of summerfallowing with little or no environmental impact. Here, we show that diversifying cropping systems with pulse crops can enhance soil water conservation, improve soil N availability, and increase system productivity. A 3-yr cropping sequence study, repeated for five cycles in Saskatchewan from 2005 to 2011, shows that both pulse- and summerfallow-based systems enhances soil N availability, but the pulse system employs biological fixation of atmospheric N2, whereas the summerfallow-system relies on 'mining' soil N with depleting soil organic matter. In a 3-yr cropping cycle, the pulse system increased total grain production by 35.5%, improved protein yield by 50.9%, and enhanced fertilizer-N use efficiency by 33.0% over the summerfallow system. Diversifying cropping systems with pulses can serve as an effective alternative to summerfallowing in rainfed dry areas. PMID:26424172

  3. Diversifying crop rotations with pulses enhances system productivity

    PubMed Central

    Gan, Yantai; Hamel, Chantal; O’Donovan, John T.; Cutforth, Herb; Zentner, Robert P.; Campbell, Con A.; Niu, Yining; Poppy, Lee

    2015-01-01

    Agriculture in rainfed dry areas is often challenged by inadequate water and nutrient supplies. Summerfallowing has been used to conserve rainwater and promote the release of nitrogen via the N mineralization of soil organic matter. However, summerfallowing leaves land without any crops planted for one entire growing season, creating lost production opportunity. Additionally, summerfallowing has serious environmental consequences. It is unknown whether alternative systems can be developed to retain the beneficial features of summerfallowing with little or no environmental impact. Here, we show that diversifying cropping systems with pulse crops can enhance soil water conservation, improve soil N availability, and increase system productivity. A 3-yr cropping sequence study, repeated for five cycles in Saskatchewan from 2005 to 2011, shows that both pulse- and summerfallow-based systems enhances soil N availability, but the pulse system employs biological fixation of atmospheric N2, whereas the summerfallow-system relies on ‘mining’ soil N with depleting soil organic matter. In a 3-yr cropping cycle, the pulse system increased total grain production by 35.5%, improved protein yield by 50.9%, and enhanced fertilizer-N use efficiency by 33.0% over the summerfallow system. Diversifying cropping systems with pulses can serve as an effective alternative to summerfallowing in rainfed dry areas. PMID:26424172

  4. System for automatically aligning a support roller system under a rotating body

    DOEpatents

    Singletary, B.H.

    1982-07-21

    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.

  5. System for automatically aligning a support roller system under a rotating body

    DOEpatents

    Singletary, B. Huston

    1983-01-01

    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.

  6. Thermal Phase Transitions in Finite Quantum Systems

    SciTech Connect

    Dean, D.J.

    2001-10-18

    In this Proceedings, the author will describe the behavior of two different quantum-mechanical systems as a function of increasing temperature. While these systems are somewhat different, the questions addressed are very similar, namely, how does one describe transitions in phase of a finite many-body system; how does one recognize these transitions in practical calculations; and how may one obtain the order of the transition.

  7. Electronic system for digital acquisition of rotational panoramic radiographs

    SciTech Connect

    McDavid, W.D.; Dove, S.B.; Welander, U.; Tronje, G. )

    1991-04-01

    A prototype system for digital panoramic imaging of the maxillofacial complex has been developed. In this system x-ray film is replaced by an electronic sensor that delivers the image information to a computer for storage in digital format. The images, which are similar to conventional panoramic radiographs, are displayed on a high-resolution video monitor and may be stored on optical disk for future use. Hard-copy output is also available. The present prototype system has been installed on an Orthopantomograph model OP10 panoramic x-ray machine is programmed for operation with this machine, but in principle the system can be installed on any such device. The system may be incorporated into the design of future panoramic x-ray systems or may be used to retrofit panoramic x-ray systems now using photographic film to record the radiographic image. Greater sensitivity of electronic sensors should make possible a reduction of x-ray dose to the patient, compared with film-based systems.

  8. Nutrients in soil water under three rotational cropping systems, Iowa, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    tSubsurface nutrient losses differ between annual and perennial crops; however, nutrient losses fromcropping systems that rotate annual and perennial crops are poorly documented. This study trackedNO3-N and P in soil water under three cropping systems suited for the U.S. Midwest, includingtwo-year (...

  9. Silicon waveguide polarization rotation Bragg grating with phase shift section and sampled grating scheme

    NASA Astrophysics Data System (ADS)

    Okayama, Hideaki; Onawa, Yosuke; Shimura, Daisuke; Yaegashi, Hiroki; Sasaki, Hironori

    2016-08-01

    We describe a Bragg grating with a phase shift section and a sampled grating scheme that converts input polarization to orthogonal polarization. A very narrow polarization-independent wavelength peak can be generated by phase shift structures and polarization-independent multiple diffraction peaks by sampled gratings. The characteristics of the device were examined by transfer matrix and finite-difference time-domain methods.

  10. The Nano-X Linear Accelerator: A Compact and Economical Cancer Radiotherapy System Incorporating Patient Rotation.

    PubMed

    Eslick, Enid M; Keall, Paul J

    2015-10-01

    Rapid technological improvements in radiotherapy delivery results in improved outcomes to patients, yet current commercial systems with these technologies on board are costly. The aim of this study was to develop a state-of-the-art cancer radiotherapy system that is economical and space efficient fitting with current world demands. The Nano-X system is a compact design that is light weight combining a patient rotation system with a vertical 6 MV fixed beam. In this paper, we present the Nano-X system design configuration, an estimate of the system dimensions and its potential impact on shielding cost reductions. We provide an assessment of implementing such a radiotherapy system clinically, its advantages and disadvantages compared to a compact conventional gantry rotating linac. The Nano-X system has several differentiating features from current radiotherapy systems, it is [1] compact and therefore can fit into small vaults, [2] light weight, and [3] engineering efficient, i.e., it rotates a relatively light component and the main treatment delivery components are not under rotation (e.g., DMLCs). All these features can have an impact on reducing the costs of the system. In terms of shielding requirements, leakage radiation was found to be the dominant contributor to the Nano-X vault and as such no primary shielding was necessary. For a low leakage design, the Nano-X vault footprint and concrete volume required is 17 m2 and 35 m3 respectively, compared to 54 m2 and 102 m3 for a conventional compact linac vault, resulting in decreased costs in shielding. Key issues to be investigated in future work are the possible patient comfort concerns associated with the patient rotation system, as well as the magnitude of deformation and subsequent adaptation requirements.

  11. Rotational testing.

    PubMed

    Furman, J M

    2016-01-01

    The natural stimulus for the semicircular canals is rotation of the head, which also might stimulate the otolith organs. Vestibular stimulation usually induces eye movements via the vestibulo-ocular reflex (VOR). The orientation of the subject with respect to the axis of rotation and the orientation of the axis of rotation with respect to gravity together determine which labyrinthine receptors are stimulated for particular motion trajectories. Rotational testing usually includes the measurement of eye movements via a video system but might use a subject's perception of motion. The most common types of rotational testing are whole-body computer-controlled sinusoidal or trapezoidal stimuli during earth-vertical axis rotation (EVAR), which stimulates primarily the horizontal semicircular canals bilaterally. Recently, manual impulsive rotations, known as head impulse testing (HIT), have been developed to assess individual horizontal semicircular canals. Most types of rotational stimuli are not used routinely in the clinical setting but may be used in selected research environments. This chapter will discuss clinically relevant rotational stimuli and several types of rotational testing that are used primarily in research settings. PMID:27638070

  12. Characteristics of steady vibration in a rotating hub-beam system

    NASA Astrophysics Data System (ADS)

    Zhao, Zhen; Liu, Caishan; Ma, Wei

    2016-02-01

    A rotating beam features a puzzling character in which its frequencies and modal shapes may vary with the hub's inertia and its rotating speed. To highlight the essential nature behind the vibration phenomena, we analyze the steady vibration of a rotating Euler-Bernoulli beam with a quasi-steady-state stretch. Newton's law is used to derive the equations governing the beam's elastic motion and the hub's rotation. A combination of these equations results in a nonlinear partial differential equation (PDE) that fully reflects the mutual interaction between the two kinds of motion. Via the Fourier series expansion within a finite interval of time, we reduce the PDE into an infinite system of a nonlinear ordinary differential equation (ODE) in spatial domain. We further nondimensionalize the ODE and discretize it via a difference method. The frequencies and modal shapes of a general rotating beam are then determined numerically. For a low-speed beam where the ignorance of geometric stiffening is feasible, the beam's vibration characteristics are solved analytically. We validate our numerical method and the analytical solutions by comparing with either the past experiments or the past numerical findings reported in existing literature. Finally, systematic simulations are performed to demonstrate how the beam's eigenfrequencies vary with the hub's inertia and rotating speed.

  13. Emergency vehicle alert system, phase 2

    NASA Technical Reports Server (NTRS)

    Barr, Tom; Harper, Warren; Reed, Bill; Wallace, David

    1993-01-01

    The EVAS provides warning for hearing-impaired motor vehicle drivers that an emergency vehicle is in the local vicinity. Direction and distance to the emergency vehicle are presented visually to the driver. This is accomplished by a special RF transmission/reception system. During this phase the receiver and transmitter from Phase 1 were updated and modified and a directional antenna developed. The system was then field tested with good results. Static and dynamic (moving vehicle) tests were made with the direction determined correctly 98 percent of the time.

  14. Cell partition in two phase polymer systems

    NASA Technical Reports Server (NTRS)

    Brooks, D. E.

    1979-01-01

    Aqueous phase-separated polymer solutions can be used as support media for the partition of biological macromolecules, organelles and cells. Cell separations using the technique have proven to be extremely sensitive to cell surface properties but application of the systems are limited to cells or aggregates which do not significantly while the phases are settling. Partition in zero g in principle removes this limitation but an external driving force must be applied to induce the phases to separate since their density difference disappears. We have recently shown that an applied electric field can supply the necessary driving force. We are proposing to utilize the NASA FES to study field-driven phase separation and cell partition on the ground and in zero g to help define the separation/partition process, with the ultimate goal being to develop partition as a zero g cell separation technique.

  15. Simple system for measuring optical rotation of glucose solution using liquid-crystal grating

    NASA Astrophysics Data System (ADS)

    Honma, Michinori; Uchida, Etsuo; Saito, Hiroo; Harada, Takeshi; Muto, Seiei; Nose, Toshiaki

    2015-12-01

    We demonstrate an optical system for measuring the concentrations of optically active media using liquid-crystal polarization gratings (LCPGs). The optical rotation angle is determined by measuring the intensities of two diffracted light beams from an LCPG combined with a quarter-wave plate (QWP). The intensity ratio is used to evaluate the optical rotation angle, minimizing the dependence on changes in light source intensity and wavelength and reducing the influence of temperature-drift-induced LC birefringence shifts. We demonstrate the system by measuring the concentration of a glucose-water solution. The measurement error caused by the slight wavelength dependence of the QWP’s retardation is assessed numerically.

  16. Rotation of a rod system containing inertial fluid flow

    NASA Astrophysics Data System (ADS)

    Sergeev, A. D.

    2012-11-01

    This paper considers a rod system for which it is possible to correctly formulate and solve the problem of three-dimensional motion in the physical space of an elastic pipeline area containing inertial incompressible fluid flow. The precession of the axis of an elastic pipeline along which inertial incompressible fluid flows is described, a physical phenomenon which has not been previously studied. With the use of rigid body dynamics, it was theoretically established that a three-dimensional dynamic process is possible in an open (exchanging mass with the environment) elastic-inertial rod system.

  17. Ray selection for optimization of rotationally symmetric systems

    NASA Astrophysics Data System (ADS)

    Forbes, Greg W.; Ruoff, Johannes; Flesch, Andreas; Kerwien, Norbert

    2016-06-01

    Efficient performance assessment is essential during the design of systems involving complex aspheres. We present new classes of pupil sampling schemes that, with a reduced number of rays, yield accurate estimates of the RMS wavefront aberration over a circular pupil. It turns out that the number of samples in the pupil can be reduced by a factor of about 0.7, and these ideas can also be expected to lead to a similar additional reduction factor when averaging over the field and color. Beyond that, analysis of a patented lens system is used to establish the path to further significant reductions.

  18. Average-passage simulation of counter-rotating propfan propulsion systems as applied to cruise missiles

    NASA Technical Reports Server (NTRS)

    Mulac, Richard A.; Schneider, Jon C.; Adamczyk, John J.

    1989-01-01

    Counter-rotating propfan (CRP) propulsion technologies are currently being evaluated as cruise missile propulsion systems. The aerodynamic integration concerns associated with this application are being addressed through the computational modeling of the missile body-propfan flowfield interactions. The work described in this paper consists of a detailed analysis of the aerodynamic interactions between the control surfaces and the propfan blades through the solution of the average-passage equation system. Two baseline configurations were studied, the control fins mounted forward of the counter-rotating propeller and the control fins mounted aft of the counter-rotating propeller. In both cases, control fin-propfan separation distance and control fin deflection angle were varied.

  19. Self locking drive system for rotating plug of a nuclear reactor

    DOEpatents

    Brubaker, James E.

    1979-01-01

    This disclosure describes a self locking drive system for rotating the plugs on the head of a nuclear reactor which is able to restrain plug motion if a seismic event should occur during reactor refueling. A servomotor is engaged via a gear train and a bull gear to the plug. Connected to the gear train is a feedback control system which allows the motor to rotate the plug to predetermined locations for refueling of the reactor. The gear train contains a self locking double enveloping worm gear set. The worm gear set is utilized for its self locking nature to prevent unwanted rotation of the plugs as the result of an earthquake. The double enveloping type is used because its unique contour spreads the load across several teeth providing added strength and allowing the use of a conventional size worm.

  20. Power system identification toolbox: Phase two progress

    SciTech Connect

    Trudnowski, D.J.

    1994-08-01

    This report describes current progress on a project funded by the Bonneville Power Administration (BPA) to develop a set of state-of-the-art analysis software (termed the Power System Identification [PSI] Toolbox) for fitting dynamic models to measured data. The project is being conducted as a three-phase effort. The first phase, completed in late 1992, involved investigating the characteristics of the analysis techniques by evaluating existing software and developing guidelines for best use. Phase Two includes extending current software, developing new analysis algorithms and software, and demonstrating and developing applications. The final phase will focus on reorganizing the software into a modular collection of documented computer programs and developing user manuals with instruction and application guidelines. Phase Two is approximately 50% complete; progress to date and a vision for the final product of the PSI Toolbox are described. The needs of the power industry for specialized system identification methods are particularly acute. The industry is currently pushing to operate transmission systems much closer to theoretical limits by using real-time, large-scale control systems to dictate power flows and maintain dynamic stability. Reliably maintaining stability requires extensive system-dynamic modeling and analysis capability, including measurement-based methods. To serve this need, the BPA has developed specialized system-identification computer codes through in-house efforts and university contract research over the last several years. To make full integrated use of the codes, as well as other techniques, the BPA has commissioned Pacific Northwest Laboratory (PNL) to further develop the codes and techniques into the PSI Toolbox.

  1. Fast Offset Laser Phase-Locking System

    NASA Technical Reports Server (NTRS)

    Shaddock, Daniel; Ware, Brent

    2008-01-01

    Figure 1 shows a simplified block diagram of an improved optoelectronic system for locking the phase of one laser to that of another laser with an adjustable offset frequency specified by the user. In comparison with prior systems, this system exhibits higher performance (including higher stability) and is much easier to use. The system is based on a field-programmable gate array (FPGA) and operates almost entirely digitally; hence, it is easily adaptable to many different systems. The system achieves phase stability of less than a microcycle. It was developed to satisfy the phase-stability requirement for a planned spaceborne gravitational-wave-detecting heterodyne laser interferometer (LISA). The system has potential terrestrial utility in communications, lidar, and other applications. The present system includes a fast phasemeter that is a companion to the microcycle-accurate one described in High-Accuracy, High-Dynamic-Range Phase-Measurement System (NPO-41927), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 22. In the present system (as in the previously reported one), beams from the two lasers (here denoted the master and slave lasers) interfere on a photodiode. The heterodyne photodiode output is digitized and fed to the fast phasemeter, which produces suitably conditioned, low-latency analog control signals which lock the phase of the slave laser to that of the master laser. These control signals are used to drive a thermal and a piezoelectric transducer that adjust the frequency and phase of the slave-laser output. The output of the photodiode is a heterodyne signal at the difference between the frequencies of the two lasers. (The difference is currently required to be less than 20 MHz due to the Nyquist limit of the current sampling rate. We foresee few problems in doubling this limit using current equipment.) Within the phasemeter, the photodiode-output signal is digitized to 15 bits at a sampling frequency of 40 MHz by use of the same analog

  2. Investigation of Control System and Display Variations on Spacecraft Handling Qualities for Docking with Stationary and Rotating Targets

    NASA Technical Reports Server (NTRS)

    Jackson, E. Bruce; Goodrich, Kenneth H.; Bailey, Randall E.; Barnes, James R.; Ragsdale, William A.; Neuhaus, Jason R.

    2010-01-01

    This paper documents the investigation into the manual docking of a preliminary version of the Crew Exploration Vehicle with stationary and rotating targets in Low Earth Orbit. The investigation was conducted at NASA Langley Research Center in the summer of 2008 in a repurposed fixed-base transport aircraft cockpit and involved nine evaluation astronauts and research pilots. The investigation quantified the benefits of a feed-forward reaction control system thruster mixing scheme to reduce translation-into-rotation coupling, despite unmodeled variations in individual thruster force levels and off-axis center of mass locations up to 12 inches. A reduced rate dead-band in the phase-plane attitude controller also showed some promise. Candidate predictive symbology overlaid on a docking ring centerline camera image did not improve handling qualities, but an innovative attitude status indicator symbol was beneficial. The investigation also showed high workload and handling quality problems when manual dockings were performed with a rotating target. These concerns indicate achieving satisfactory handling quality ratings with a vehicle configuration similar to the nominal Crew Exploration Vehicle may require additional automation.

  3. Rayleigh-Taylor stability of a two-fluid system under a general rotation field

    NASA Astrophysics Data System (ADS)

    Dávalos-Orozco, L. A.

    1996-01-01

    In this paper we investigate the Rayleigh-Taylor instability of a two-fluid layer system under a general rotation field. Gravity is always perpendicular to the two horizontal layers and rotation has an arbitrary angle with respect to the vertical. It is found that, in an unstable situation, an increase in the non-dimensional density-difference increases the stable angular area of wave propagation, measured with respect to the horizontal component of rotation. However, it is found that the vertical component of rotation reduces not only this stable angular area but also the range in which the horizontal component stabilizes the system according to a previous study by Dávalos-Orozco ( Fluid Dyn. Res., 12: 243, 1993). This decrease in stable area occurs along with a decrease in the growth rate in the unstable region. Numerical analysis of the eigenvalue equation shows that the stable angular area disappears after the non-dimensional vertical component of rotation attains the value 0.33. Exact and approximate analytical expressions for the critical values are calculated to help to understand the physics of the numerical analysis.

  4. Phase-ambiguity resolution for QPSK modulation systems. Part 2: A method to resolve offset QPSK

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien Manh

    1989-01-01

    Part 2 presents a new method to resolve the phase-ambiguity for Offset QPSK modulation systems. When an Offset Quaternary Phase-Shift-Keyed (OQPSK) communications link is utilized, the phase ambiguity of the reference carrier must be resolved. At the transmitter, two different unique words are separately modulated onto the quadrature carriers. At the receiver, the recovered carrier may have one of four possible phases, 0, 90, 180, or 270 degrees, referenced to the nominally correct phase. The IF portion of the channel may cause a phase-sense reversal, i.e., a reversal in the direction of phase rotation for a specified bit pattern. Hence, eight possible phase relationships (the so-called eight ambiguous phase conditions) between input and output of the demodulator must be resolved. Using the In-phase (I)/Quadrature (Q) channel reversal correcting property of an OQPSK Costas loop with integrated symbol synchronization, four ambiguous phase conditions are eliminated. Thus, only four possible ambiguous phase conditions remain. The errors caused by the remaining ambiguous phase conditions can be corrected by monitoring and detecting the polarity of the two unique words. The correction of the unique word polarities results in the complete phase-ambiguity resolution for the OQPSK system.

  5. Phase-ambiguity resolution for QPSK modulation systems. Part 2: A method to resolve offset QPSK

    NASA Astrophysics Data System (ADS)

    Nguyen, Tien Manh

    1989-05-01

    Part 2 presents a new method to resolve the phase-ambiguity for Offset QPSK modulation systems. When an Offset Quaternary Phase-Shift-Keyed (OQPSK) communications link is utilized, the phase ambiguity of the reference carrier must be resolved. At the transmitter, two different unique words are separately modulated onto the quadrature carriers. At the receiver, the recovered carrier may have one of four possible phases, 0, 90, 180, or 270 degrees, referenced to the nominally correct phase. The IF portion of the channel may cause a phase-sense reversal, i.e., a reversal in the direction of phase rotation for a specified bit pattern. Hence, eight possible phase relationships (the so-called eight ambiguous phase conditions) between input and output of the demodulator must be resolved. Using the In-phase (I)/Quadrature (Q) channel reversal correcting property of an OQPSK Costas loop with integrated symbol synchronization, four ambiguous phase conditions are eliminated. Thus, only four possible ambiguous phase conditions remain. The errors caused by the remaining ambiguous phase conditions can be corrected by monitoring and detecting the polarity of the two unique words. The correction of the unique word polarities results in the complete phase-ambiguity resolution for the OQPSK system.

  6. ISDSN Sensor System Phase One Test Report

    SciTech Connect

    Gail Heath

    2011-09-01

    This Phase 1 Test Report documents the test activities and results completed for the Idaho National Laboratory (INL) sensor systems that will be deployed in the meso-scale test bed (MSTB) at Florida International University (FIU), as outlined in the ISDSN-MSTB Test Plan. This report captures the sensor system configuration tested; test parameters, testing procedure, any noted changes from the implementation plan, acquired test data sets, and processed results.

  7. Electronic Equipment Maintenance Training (EEMT) System: System Definition Phase.

    ERIC Educational Resources Information Center

    Pine, S. M.; And Others

    The second in a series of four reports on the Electronic Equipment Maintenance Training (EEMT) project, this document summarizes the system definition phase of the EEMT program. The purpose of this phase of the project was to define a comprehensive set of functions and training requirements that the EEMT must satisfy within the training mission of…

  8. In-flight investigation of a rotating cylinder-based structural excitation system for flutter testing

    NASA Technical Reports Server (NTRS)

    Vernon, Lura

    1993-01-01

    A research excitation system was test flown at the NASA Dryden Flight Research Facility on the two-seat F-16XL aircraft. The excitation system is a wingtip-mounted vane with a rotating slotted cylinder at the trailing edge. As the cylinder rotates during flight, the flow is alternately deflected upward and downward through the slot, resulting in a periodic lift force at twice the cylinder's rotational frequency. Flight testing was conducted to determine the excitation system's effectiveness in the subsonic, transonic, and supersonic flight regimes. Primary research objectives were to determine the system's ability to develop adequate force levels to excite the aircraft's structure and to determine the frequency range over which the system could excite structural modes of the aircraft. In addition, studies were conducted to determine optimal excitation parameters, such as sweep duration, sweep type, and energy levels. The results from the exciter were compared with results from atmospheric turbulence excitation at the same flight conditions. The comparison indicated that the vane with a rotating slotted cylinder provides superior results. The results from the forced excitation were of higher quality and had less variation than the results from atmospheric turbulence. The forced excitation data also invariably yielded higher structural damping values than those from the atmospheric turbulence data.

  9. Identification of the direction and value of the wave length of each mode for a rotating tire using the phase difference method

    NASA Astrophysics Data System (ADS)

    Lee, Jongsuh; Wang, Semyung; Kindt, Peter; Pluymers, Bert; Desmet, Wim

    2016-02-01

    Natural frequencies, mode shapes and modal damping values are the most important parameters to describe the noise and vibration behavior of a mechanical system. For rotating machinery, however, the directivity of the propagation wave and the wave length of each mode should also be taken into account. Generally, the information on directivity and wave length is obtained on the basis of the mode shape result, which is estimated from several measurements measured at different locations. In this research, the accurate directivity and wave length results will be observed by calculating the phase difference at two different locations. The limitation of the proposed method, which arises from the difference between the assumed ring model and the real tire, will be explained, and a method to address the limitation is introduced. The proposed method is verified by applying it to experimental measurements, and a brief explanation of the obtained results is provided.

  10. Forced axial segregation in axially inhomogeneous rotating systems.

    PubMed

    González, S; Windows-Yule, C R K; Luding, S; Parker, D J; Thornton, A R

    2015-08-01

    Controlling segregation is both a practical and a theoretical challenge. Using a novel drum design comprising concave and convex geometry, we explore, through the application of both discrete particle simulations and positron emission particle tracking, a means by which radial size segregation may be used to drive axial segregation, resulting in an order of magnitude increase in the rate of separation. The inhomogeneous drum geometry explored also allows the direction of axial segregation within a binary granular bed to be controlled, with a stable, two-band segregation pattern being reliably and reproducibly imposed on the bed for a variety of differing system parameters. This strong banding is observed to persist even in systems that are highly constrained in the axial direction, where such segregation would not normally occur. These findings, and the explanations provided of their underlying mechanisms, could lead to radical new designs for a broad range of particle processing applications but also may potentially prove useful for medical and microflow applications. PMID:26382389

  11. Forced axial segregation in axially inhomogeneous rotating systems

    NASA Astrophysics Data System (ADS)

    González, S.; Windows-Yule, C. R. K.; Luding, S.; Parker, D. J.; Thornton, A. R.

    2015-08-01

    Controlling segregation is both a practical and a theoretical challenge. Using a novel drum design comprising concave and convex geometry, we explore, through the application of both discrete particle simulations and positron emission particle tracking, a means by which radial size segregation may be used to drive axial segregation, resulting in an order of magnitude increase in the rate of separation. The inhomogeneous drum geometry explored also allows the direction of axial segregation within a binary granular bed to be controlled, with a stable, two-band segregation pattern being reliably and reproducibly imposed on the bed for a variety of differing system parameters. This strong banding is observed to persist even in systems that are highly constrained in the axial direction, where such segregation would not normally occur. These findings, and the explanations provided of their underlying mechanisms, could lead to radical new designs for a broad range of particle processing applications but also may potentially prove useful for medical and microflow applications.

  12. Design and experimental characterization of a nonintrusive measurement system of rotating blade vibration

    SciTech Connect

    Nava, P. ); Paone, N.; Rossi, G.L.; Tomasini, E.P. . Dipt. di Meccanica)

    1994-07-01

    A measurement system for nonintrusive monitoring of rotating blade vibration in turbomachines based on fiber optic sensors is presented. The design of the whole system is discussed; the development of special purpose sensors, their interfacing to the data acquisition system, and the signal processing are outlined.The processing algorithms are tested by software simulation for several possible blade vibrations. Experimental tests performed on different bladed rotors are presented. Results are compared to simultaneous strain gage measurements.

  13. Rotation of nilotinib and imatinib for first-line treatment of chronic phase chronic myeloid leukemia.

    PubMed

    Gugliotta, Gabriele; Castagnetti, Fausto; Breccia, Massimo; Gozzini, Antonella; Usala, Emilio; Carella, Angelo M; Rege-Cambrin, Giovanna; Martino, Bruno; Abruzzese, Elisabetta; Albano, Francesco; Stagno, Fabio; Luciano, Luigia; D'Adda, Mariella; Bocchia, Monica; Cavazzini, Francesco; Tiribelli, Mario; Lunghi, Monia; Pia Falcone, Antonietta; Musolino, Caterina; Levato, Luciano; Venturi, Claudia; Soverini, Simona; Cavo, Michele; Alimena, Giuliana; Pane, Fabrizio; Martinelli, Giovanni; Saglio, Giuseppe; Rosti, Gianantonio; Baccarani, Michele

    2016-06-01

    The introduction of second-generation tyrosine-kinase inhibitors (TKIs) has generated a lively debate on the choice of first-line TKI in chronic phase, chronic myeloid leukemia (CML). Despite the TKIs have different efficacy and toxicity profiles, the planned use of two TKIs has never been investigated. We report on a phase 2 study that was designed to evaluate efficacy and safety of a treatment alternating nilotinib and imatinib, in newly diagnosed BCR-ABL1 positive, chronic phase, CML patients. One hundred twenty-three patients were enrolled. Median age was 56 years. The probabilities of achieving a complete cytogenetic response, a major molecular response, and a deep molecular response (MR 4.0) by 2 years were 93%, 87%, and 61%, respectively. The 5-year overall survival and progression-free survival were 89%. Response rates and survival are in the range of those reported with nilotinib alone. Moreover, we observed a relatively low rate of cardiovascular adverse events (5%). These data show that the different efficacy and toxicity profiles of TKIs could be favorably exploited by alternating their use. Am. J. Hematol. 91:617-622, 2016. © 2016 Wiley Periodicals, Inc.

  14. Rotation of nilotinib and imatinib for first-line treatment of chronic phase chronic myeloid leukemia.

    PubMed

    Gugliotta, Gabriele; Castagnetti, Fausto; Breccia, Massimo; Gozzini, Antonella; Usala, Emilio; Carella, Angelo M; Rege-Cambrin, Giovanna; Martino, Bruno; Abruzzese, Elisabetta; Albano, Francesco; Stagno, Fabio; Luciano, Luigia; D'Adda, Mariella; Bocchia, Monica; Cavazzini, Francesco; Tiribelli, Mario; Lunghi, Monia; Pia Falcone, Antonietta; Musolino, Caterina; Levato, Luciano; Venturi, Claudia; Soverini, Simona; Cavo, Michele; Alimena, Giuliana; Pane, Fabrizio; Martinelli, Giovanni; Saglio, Giuseppe; Rosti, Gianantonio; Baccarani, Michele

    2016-06-01

    The introduction of second-generation tyrosine-kinase inhibitors (TKIs) has generated a lively debate on the choice of first-line TKI in chronic phase, chronic myeloid leukemia (CML). Despite the TKIs have different efficacy and toxicity profiles, the planned use of two TKIs has never been investigated. We report on a phase 2 study that was designed to evaluate efficacy and safety of a treatment alternating nilotinib and imatinib, in newly diagnosed BCR-ABL1 positive, chronic phase, CML patients. One hundred twenty-three patients were enrolled. Median age was 56 years. The probabilities of achieving a complete cytogenetic response, a major molecular response, and a deep molecular response (MR 4.0) by 2 years were 93%, 87%, and 61%, respectively. The 5-year overall survival and progression-free survival were 89%. Response rates and survival are in the range of those reported with nilotinib alone. Moreover, we observed a relatively low rate of cardiovascular adverse events (5%). These data show that the different efficacy and toxicity profiles of TKIs could be favorably exploited by alternating their use. Am. J. Hematol. 91:617-622, 2016. © 2016 Wiley Periodicals, Inc. PMID:26971721

  15. Ocular Reflex Phase During Off-Vertical Axis Rotation In Humans Is Modified By Head-On-Trunk Position

    NASA Technical Reports Server (NTRS)

    Wood, Scott; Clement, Gilles; Denise, Pierre; Reschke, Millard

    2005-01-01

    Constant velocity Off-Vertical Axis Rotation (OVAR) imposes a continuously varying orientation of the head and body relative to gravity. The ensuing ocular reflexes include modulation of both horizontal and torsional eye velocity as a function of the varying linear acceleration along the lateral plane. The purpose of this study was to examine whether the modulation of these ocular reflexes would be modified by different head-on-trunk positions. Ten human subjects were rotated in darkness about their longitudinal axis 20 deg off-vertical at constant rates of 45 and 180 deg/s, corresponding to 0.125 and 0.5 Hz. Binocular responses were obtained with video-oculography with the head and trunk aligned, and then with the head turned relative to the trunk 40 deg to the right or left of center. Sinusoidal curve fits were used to derive amplitude, phase and bias velocity of the eye movements across multiple cycles for each head-on-trunk position. Consistent with previous studies, the modulation of torsional eye movements was greater at 0.125 Hz while the modulation of horizontal eye movements was greater at 0.5 Hz. Neither amplitude nor bias velocities were significantly altered by head-on-trunk position. The phases of both torsional and horizontal ocular reflexes, on the other hand, shifted towards alignment with the head. These results are consistent with the modulation of torsional and horizontal ocular reflexes during OVAR being primarily mediated by the otoliths in response to the sinusoidally varying linear acceleration along the interaural head axis.

  16. Viking radio science data analysis and synthesis. [rotation of Mars, solar system dynamics, and gravitational laws

    NASA Technical Reports Server (NTRS)

    Shapiro, I. I.

    1984-01-01

    The rotational motion of Mars and its geophysical ramifications were investigated. Solar system dynamics and the laws of gravitation were also studied. The planetary ephemeris program, which was the central element in data analysis for this project, is described in brief. Viking Lander data were used in the investigation.

  17. Nonlinear stability of overcompresive shock waves in a rotationally invariant system of viscous conservation laws

    NASA Astrophysics Data System (ADS)

    Freistühler, Heinrich; Liu, Tai-Ping

    1993-04-01

    This paper proves that certain non-classical shock waves in a rotationally invariant system of viscous conservation laws posses nonlinear large-time stability against sufficiently small perturbations. The result applies to small intermediate magnetohydrodynamic shocks in the presence of dissipation.

  18. Crop rotations that include legumes and reduced tillage improve the energy efficiency of crop production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern crop production requires large inputs of energy and these inputs represent a substantial cost. Management practices such as crop rotation and choice of tillage practice influence the energy balance for a production system. Legumes support bacteria that are capable of fixing nitrogen (N). This...

  19. Crop rotations that include legumes and reduced tillage improve the energy efficiency of crop production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Text: Modern crop production requires large inputs of energy and these inputs represent a substantial cost. Management practices such as crop rotation and choice of tillage practice influence the energy balance for a production system. Legumes support bacteria that are capable of fixing nitrogen (N)...

  20. Ultrahigh-speed rotating nanoelectromechanical system devices assembled from nanoscale building blocks

    NASA Astrophysics Data System (ADS)

    Kim, Kwanoh; Xu, Xiaobin; Guo, Jianhe; Fan, D. L.

    2014-04-01

    The development of rotary nanomotors is crucial for advancing nanoelectromechanical system technology. In this work, we report design, assembly and rotation of ordered arrays of nanomotors. The nanomotors are bottom-up assembled from nanoscale building blocks with nanowires as rotors, patterned nanomagnets as bearings and quadrupole microelectrodes as stators. Arrays of nanomotors rotate with controlled angle, speed (over 18,000 r.p.m.), and chirality by electric fields. Using analytical modelling, we reveal the fundamental nanoscale electrical, mechanical and magnetic interactions in the nanomotor system, which excellently agrees with experimental results and provides critical understanding for designing metallic nanoelectromechanical systems. The nanomotors can be continuously rotated for 15 h over 240,000 cycles. They are applied for controlled biochemical release and demonstrate releasing rate of biochemicals on nanoparticles that can be precisely tuned by mechanical rotations. The innovations reported in this research, from concept, design and actuation to application, are relevant to nanoelectromechanical system, nanomedicine, microfluidics and lab-on-a-chip architectures.

  1. Ultrahigh-speed rotating nanoelectromechanical system devices assembled from nanoscale building blocks.

    PubMed

    Kim, Kwanoh; Xu, Xiaobin; Guo, Jianhe; Fan, D L

    2014-04-07

    The development of rotary nanomotors is crucial for advancing nanoelectromechanical system technology. In this work, we report design, assembly and rotation of ordered arrays of nanomotors. The nanomotors are bottom-up assembled from nanoscale building blocks with nanowires as rotors, patterned nanomagnets as bearings and quadrupole microelectrodes as stators. Arrays of nanomotors rotate with controlled angle, speed (over 18,000 r.p.m.), and chirality by electric fields. Using analytical modelling, we reveal the fundamental nanoscale electrical, mechanical and magnetic interactions in the nanomotor system, which excellently agrees with experimental results and provides critical understanding for designing metallic nanoelectromechanical systems. The nanomotors can be continuously rotated for 15 h over 240,000 cycles. They are applied for controlled biochemical release and demonstrate releasing rate of biochemicals on nanoparticles that can be precisely tuned by mechanical rotations. The innovations reported in this research, from concept, design and actuation to application, are relevant to nanoelectromechanical system, nanomedicine, microfluidics and lab-on-a-chip architectures.

  2. Development of a rotary instrumentation system, phase 2

    NASA Astrophysics Data System (ADS)

    Adler, A.; Skidmore, W.

    1982-12-01

    A rotary instrumentation system which consists of ruggedized miniature telemetry transmitters installed on the rotating shaft of a gas turbine engine to telemeter the outputs of sensors (strain gages, thermocouples, etc.) on rotating engine components was designed. A small prototype system, which demonstrates the capabilities of performing in the intended environment and demonstrates that the system is expandable to handle about 100 data channels was developed.

  3. Evidence from stellar rotation of enhanced disc dispersal. I. The case of the triple visual system BD-21 1074 in the β Pictoris association

    NASA Astrophysics Data System (ADS)

    Messina, S.; Monard, B.; Biazzo, K.; Melo, C. H. F.; Frasca, A.

    2014-10-01

    Context. The early stage of stellar evolution is characterized by a magnetic coupling between a star and its accretion disc, known as a star-disc locking mechanism. The disc-locking prevents the star to spin its rotation up, and its timescale depends on the disc lifetime, which should not be longer than about 10 Myr. Some mechanisms can significantly shorten this lifetime, allowing a few stars to start spinning up much earlier than other stars and increasing the observed rotation period dispersion among coeval stars. Aims: In the present study, we aim to investigate how the properties of the circumstellar environment can shorten the disc lifetime, more specifically the presence of a close stellar companion. Methods: We have identified a few multiple stellar systems, composed of stars with similar masses, which belong to associations with a known age. Since all parameters that are responsible for the rotational evolution, with the exception of environment properties and initial stellar rotation, are similar for all components, we expect that significant differences among the rotation periods can only arise from differences in the disc lifetimes. A photometric timeseries allowed us to measure the rotation periods of each component, while high-resolution spectra provided us with the fundamental parameters, v sin i and chromospheric line fluxes. Results: In the present study, we have collected timeseries photometry of BD-21 1074, a member of the 21 Myr old β Pictoris association, and measured the rotation periods of its brightest components A and B. They differ significantly, and the component B, which has a closer companion C, rotates faster than the more distant and isolated component A. It also displays a slightly higher chromospheric activity level. Conclusions: Since components A and B have similar mass, age, and initial chemical composition, we can ascribe the rotation period difference to either different initial rotation periods or different disc

  4. Phase discriminating capacitive array sensor system

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor); Rahim, Wadi (Inventor)

    1993-01-01

    A phase discriminating capacitive sensor array system which provides multiple sensor elements which are maintained at a phase and amplitude based on a frequency reference provided by a single frequency stabilized oscillator. Sensor signals provided by the multiple sensor elements are controlled by multiple phase control units, which correspond to the multiple sensor elements, to adjust the sensor signals from the multiple sensor elements based on the frequency reference. The adjustment made to the sensor signals is indicated by output signals which indicate the proximity of the object. The output signals may also indicate the closing speed of the object based on the rate of change of the adjustment made, and the edges of the object based on a sudden decrease in the adjustment made.

  5. Phase change fluids for solar thermal systems

    SciTech Connect

    Sama, D.A.; Sladek, K.J.

    1981-01-01

    This study explores the use, for storage of solar energy, of phase change materials which are suspended or emulsified in an immiscible carrier fluid. Emulsions of up to 50 weight % paraffin wax in water were found to be very fluid, highly stable, and quite flame resistant. Such easily pumped emulsions allow for an increase in stored energy density while avoiding the severe heat transfer rate problems normally encountered with phase change storage. Since the suspended phase change materials can be used both to collect and store solar energy, a heat transfer step is eliminated and the energy may be stored at a higher average temperature. This in turn results in a higher thermodynamic availability which is shown to be particularly advantageous in the storage of solar energy for refrigeration or heat pump systems. 6 refs.

  6. An Accurate Calibration Method Based on Velocity in a Rotational Inertial Navigation System.

    PubMed

    Zhang, Qian; Wang, Lei; Liu, Zengjun; Feng, Peide

    2015-01-01

    Rotation modulation is an effective method to enhance the accuracy of an inertial navigation system (INS) by modulating the gyroscope drifts and accelerometer bias errors into periodically varying components. The typical RINS drives the inertial measurement unit (IMU) rotation along the vertical axis and the horizontal sensors' errors are modulated, however, the azimuth angle error is closely related to vertical gyro drift, and the vertical gyro drift also should be modulated effectively. In this paper, a new rotation strategy in a dual-axis rotational INS (RINS) is proposed and the drifts of three gyros could be modulated, respectively. Experimental results from a real dual-axis RINS demonstrate that the maximum azimuth angle error is decreased from 0.04° to less than 0.01° during 1 h. Most importantly, the changing of rotation strategy leads to some additional errors in the velocity which is unacceptable in a high-precision INS. Then the paper studies the basic reason underlying horizontal velocity errors in detail and a relevant new calibration method is designed. Experimental results show that after calibration and compensation, the fluctuation and stages in the velocity curve disappear and velocity precision is improved. PMID:26225983

  7. An Accurate Calibration Method Based on Velocity in a Rotational Inertial Navigation System

    PubMed Central

    Zhang, Qian; Wang, Lei; Liu, Zengjun; Feng, Peide

    2015-01-01

    Rotation modulation is an effective method to enhance the accuracy of an inertial navigation system (INS) by modulating the gyroscope drifts and accelerometer bias errors into periodically varying components. The typical RINS drives the inertial measurement unit (IMU) rotation along the vertical axis and the horizontal sensors’ errors are modulated, however, the azimuth angle error is closely related to vertical gyro drift, and the vertical gyro drift also should be modulated effectively. In this paper, a new rotation strategy in a dual-axis rotational INS (RINS) is proposed and the drifts of three gyros could be modulated, respectively. Experimental results from a real dual-axis RINS demonstrate that the maximum azimuth angle error is decreased from 0.04° to less than 0.01° during 1 h. Most importantly, the changing of rotation strategy leads to some additional errors in the velocity which is unacceptable in a high-precision INS. Then the paper studies the basic reason underlying horizontal velocity errors in detail and a relevant new calibration method is designed. Experimental results show that after calibration and compensation, the fluctuation and stages in the velocity curve disappear and velocity precision is improved. PMID:26225983

  8. On representing rotations by Rodrigues parameters in non-orthonormal reference systems.

    PubMed

    Morawiec, A

    2016-09-01

    A Rodrigues vector is a triplet of real numbers used for parameterizing rotations or orientations in three-dimensional space. Because of its properties (e.g. simplicity of fundamental regions for misorientations) this parameterization is frequently applied in analysis of orientation maps of polycrystalline materials. By conventional definition, the Rodrigues parameters are specified in orthonormal coordinate systems, whereas the bases of crystal lattices are generally non-orthogonal. Therefore, the definition of Rodrigues parameters is extended so they can be directly linked to non-Cartesian bases of a crystal. The new parameters are co- or contravariant components of vectors specified with respect to the same basis as atomic positions in a unit cell. The generalized formalism allows for redundant crystallographic axes. The formulas for rotation composition and the relationship to the rotation matrix are similar to those used in the Cartesian case, but they have a wider range of applicability: calculations can be performed with an arbitrary metric tensor of the crystal lattice. The parameterization in oblique coordinate frames of lattices is convenient for crystallographic applications because the generalized parameters are directly related to indices of rotation-invariant lattice directions and rotation-invariant lattice planes. PMID:27580203

  9. Boundary Layer Control of Rotating Convection Systems: the Transition from 2D to 3D Turbulence

    NASA Astrophysics Data System (ADS)

    King, Eric; Stellmach, S.; Noir, J.; Hansen, U.; Aurnou, J.

    2008-09-01

    Recent studies have reproduced the patterns of zonal flow and thermal emission on the Giant Planets using deep convection models. For example, it has been shown that the fundamental differences between the winds of the Ice Giants, Uranus and Neptune, and the Gas Giants, Jupiter and Saturn, may be explained by the breakdown of the influence of rotation on convection. Here, we present results from a coupled suite of laboratory experiments and numerical simulations of rotating convection which span a broad range of parameter space. We observe distinct transitions from rotationally controlled, quasi-2D dynamics to strongly 3D, non-rotating style convection. We quantify the boundary between these two regimes as a function of the Rayleigh and Ekman numbers. The transition is not determined, as long assumed, by the convective Rossby number, but instead is controlled by boundary layer dynamics. It may then be easier than previously thought for convection systems to break free from the constraints of rotation. We are presently investigating how this transition correlates with zonal flows and magnetic field generation on the Giant Planets. Funding provided by NSF Geophysics Program (EAR/IF) and NASA Planetary Atmospheres Program.

  10. [Symmetry types, systems and multiplicity of the structure of adenovirus capsid. II. Rotational facet-groups of five-, three- and two-fold symmetry axes].

    PubMed

    Nász, István; Adám, Eva

    2006-01-01

    The icosahedral adenovirus capsid has three rotational axes of different types. The six five-fold, ten three-fold and the fifteen two-fold axes have two superficial points each, altogether 62. The axes determine the number and location of the identical rotational facet groups and that during the different rotational phases which other regular facets and with what multiplicity shall be covered by them. The number of rotational facets of the five-, three- and two-fold rotational symmetry axes is 4, 6.66 and 10, respectively. In all the three cases, there are two kinds of possible arrangements of the facets. During the rotation - when the facets of the facet group placed on one by one to the neighbouring identical facet groups - at the five-fold axes, the facets of the rotational facet group get into cover position 12 times with all the 20 regular capsid facets, 20 times at the three-fold axes, and 30 times at the two-fold axes in a way that a different facet combination (facet hit) falls to every facet, and the original symmetry is not disturbed. After all, this means 240, 400 and 600 facet combinations, i.e. multiplicity in case of five-, three- and two-fold symmetry axes respectively, and these numbers correspond with that of the theoretically possible variations. The same results can be calculated by multiplying the number of real rotations of the capsid bringing the body into itself i.e. the number 60 with the number of facets contributing to the five-, three- and two-fold rotational phases. The other way of the determination of multiplicity takes into account that all the facet groups of the capsid rotate simultaneously during all the rotational phases, and this multiplies the number of multiplicity with the number of the rotational types five-, three- and two-fold which result in one and the same multiplicity number in the case of five-, three- and two-fold symmetry, alike 1200. Perpendicular to the five-fold symmetry axes with the line of intersection drawn

  11. Advanced Wastewater Treatment Engineering-Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling.

    PubMed

    Paul, Parneet; Jones, Franck Anderson

    2016-01-05

    Advanced wastewater treatment using membranes are popular environmental system processes since they allow reuse and recycling. However, fouling is a key limiting factor and so proprietary systems such as Avanti's RPU-185 Flexidisks membrane bioreactor (MBR) use novel rotating membranes to assist in ameliorating it. In earlier research, this rotating process was studied by creating a simulation model based on first principles and traditional fouling mechanisms. In order to directly compare the potential benefits of this rotational system, this follow-up study was carried out using Avanti's newly developed static (non-rotating) Flexidisks MBR system. The results from operating the static pilot unit were simulated and modelled using the rotational fouling model developed earlier however with rotational switching functions turned off and rotational parameters set to a static mode. The study concluded that a rotating MBR system could increase flux throughput when compared against a similar static system. It is thought that although the slowly rotating spindle induces a weak crossflow shear, it is still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded at the micro level and lessening the potential of rapid trans-membrane pressure increases at the macro level.

  12. Advanced Wastewater Treatment Engineering—Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling

    PubMed Central

    Paul, Parneet; Jones, Franck Anderson

    2016-01-01

    Advanced wastewater treatment using membranes are popular environmental system processes since they allow reuse and recycling. However, fouling is a key limiting factor and so proprietary systems such as Avanti’s RPU-185 Flexidisks membrane bioreactor (MBR) use novel rotating membranes to assist in ameliorating it. In earlier research, this rotating process was studied by creating a simulation model based on first principles and traditional fouling mechanisms. In order to directly compare the potential benefits of this rotational system, this follow-up study was carried out using Avanti’s newly developed static (non-rotating) Flexidisks MBR system. The results from operating the static pilot unit were simulated and modelled using the rotational fouling model developed earlier however with rotational switching functions turned off and rotational parameters set to a static mode. The study concluded that a rotating MBR system could increase flux throughput when compared against a similar static system. It is thought that although the slowly rotating spindle induces a weak crossflow shear, it is still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded at the micro level and lessening the potential of rapid trans-membrane pressure increases at the macro level. PMID:26742053

  13. Advanced Wastewater Treatment Engineering-Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling.

    PubMed

    Paul, Parneet; Jones, Franck Anderson

    2016-01-01

    Advanced wastewater treatment using membranes are popular environmental system processes since they allow reuse and recycling. However, fouling is a key limiting factor and so proprietary systems such as Avanti's RPU-185 Flexidisks membrane bioreactor (MBR) use novel rotating membranes to assist in ameliorating it. In earlier research, this rotating process was studied by creating a simulation model based on first principles and traditional fouling mechanisms. In order to directly compare the potential benefits of this rotational system, this follow-up study was carried out using Avanti's newly developed static (non-rotating) Flexidisks MBR system. The results from operating the static pilot unit were simulated and modelled using the rotational fouling model developed earlier however with rotational switching functions turned off and rotational parameters set to a static mode. The study concluded that a rotating MBR system could increase flux throughput when compared against a similar static system. It is thought that although the slowly rotating spindle induces a weak crossflow shear, it is still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded at the micro level and lessening the potential of rapid trans-membrane pressure increases at the macro level. PMID:26742053

  14. An induction Linac approach to phase rotation of a muon bunch in the production region of {mu}{sup +}-{mu}{sup {minus}} colliders

    SciTech Connect

    Turner, W.C.

    1995-11-22

    The possibility of using an induction linac for phase rotation, or equivalently flattening the head to tail mean energy sweep, of a muon bunch in the production region of a {mu}{sup +} {minus} {mu}{sup {minus}} is examined. Axial spreading of an accelerating bunch is analyzed and the form of appropriate induction cell voltage waveforms is derived. A set of parametric equations for the induction accelerator structure is given and specific solutions are presented which demonstrate the technological feasibility of the induction linac approach to phase rotation.

  15. Fermionic Paired Superfluids at High Rotation Rate

    NASA Astrophysics Data System (ADS)

    Veillette, Martin Y.; Sheehy, Daniel E.; Gurarie, Victor; Radzihovsky, Leo

    2006-03-01

    I will describe our recent work on rotating resonantly-paired superfluids, mapping out the Feshbach resonance detuning, temperature and rotational frequency phase diagram. I will compare our predictions with the recent experiments on degenerate atomic ^6Li gases across a Feshbach resonance [Zwierlein et al. Nature 435, 1047 (2005)] and will make proposals for future experiments in such systems.

  16. [Nutrient management strategy of paddy rice-upland crop rotation system].

    PubMed

    Fan, Ming-Sheng; Jiang, Rong-Feng; Zhang, Fu-Suo; Lü, Shi-Hua; Liu, Xue-Jun

    2008-02-01

    Paddy rice-upland crop rotation system is a major cropping system in China, and practiced widely along the Yangtze River basin. A unique feature of this system is the annual conversion of soil from aerobic to anaerobic and then back to aerobic condition, which can result in the changes of soil physical, chemical, and biological prosperities among seasons, making a special agroecosystem. The major challenges faced by this system include declining or stagnating productivity, increasing shortage of irrigation water, improper management of nutrients, low efficiency of resource utilization, and environmental pollution. Based on an overview of the characteristics and problems of paddy rice-upland crop rotation system, this paper put forward a strategy of practicing integrated nutrient management to solve the contradictions between nutrient input, crop production and environmental risk. The key points of this strategy included nutrient management from the whole rotation system perspective, integrated use of nutrients from various sources (chemical fertilizers, organic fertilizers, and nutrients from the environment), synchronization of nutrient supply and crop nutrient demand, application of different management technologies based on the characteristics of different nutrient resources, and integration of nutrient management with other cropping system technologies like water saving and high-yielding cultivation, etc.

  17. Torsional vibration measurements on rotating shaft system using laser doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Xiang, Ling; Yang, Shixi; Gan, Chunbiao

    2012-11-01

    In this work, a laser torsional vibrameter was used to measure the torsion vibration of a rotating shaft system under electrical network impact. Based on the principles of laser Doppler velocimetry, the laser torsional vibrometer (LTV) are non-contact measurement of torsional oscillation of rotating shafts, offering significant advantages over conventional techniques. Furthermore, a highly complex shafting system is analyzed by a modified Riccati torsional transfer matrix. The system is modeled as a chain consisting of an elastic spring with concentrated mass points, and the multi-segments lumped mass model is established for this shafting system. By the modified Riccati torsional transfer matrix method, an accumulated calculation is effectively eliminated to obtain the natural frequencies. The electrical network impacts can activize the torsional vibration of shaft system, and the activized torsion vibration frequencies contained the natural frequencies of shaft system. The torsional vibrations of the shaft system were measured under electrical network impacts in laser Doppler torsional vibrometer. By comparisons, the natural frequencies by measurement were consistent with the values by calculation. The results verify the instrument is robust, user friendly and can be calibrated in situ. The laser torsional vibrometer represents a significant step forward in rotating machinery diagnostics.

  18. The IAU resolutions on astronomical reference systems, time scales, and earth rotation models : explanation and implementation

    NASA Astrophysics Data System (ADS)

    Kaplan, George H.

    Recent resolutions passed by the International Astronomical Union (IAU) on astronomical reference systems, time scales, and Earth rotation models are the most significant set of international agreements in positional astronomy in several decades. These resolutions, the result of over ten years of international research and study, provide a coherent set of foundational standards for the treatment of astrometric data and the modeling of dynamics in the solar system. This circular explains these resolutions and provides a complete set of practical formulas for their implementation. The six main chapters cover relativity, time scales, the fundamental celestial reference system, ephemerides of solar system bodies, precession and nutation, and modeling the Earth's rotation. "Errata in this circular and updates to it are given at http://aa.usno.navy.mil/publications/docs/Circular_179.html

  19. The construction of an electrode biasing system for driving plasma rotation in J-TEXT tokamak

    NASA Astrophysics Data System (ADS)

    Zhu, T. Z.; Chen, Z. P.; Sun, Yue; Nan, J. Y.; Liu, H.; Zhuang, G.; Wang, Z. J.

    2014-05-01

    A newly designed electrode biasing system has been constructed for driving plasma rotation in J-TEXT tokamak. To reduce the influence to the plasma, the system contains a pneumatic driving system so that it can reciprocate in a single discharge, with a stroke of about 5 cm in 100 ms. The power supply of the system can provide stable and adjustable dc voltage in the range of 0-700 V, with adjustable duration of 10-200 ms; its instantaneous power output can reach up to more than 200 kW. In addition, the power supply can also provide a multi-cycle voltage waveform, with adjustable pulse width and voltage amplitude. When applying a positive bias to the plasma, both an improvement of plasma confinement and the speed-up of plasma-edge toroidal rotation in the same direction of plasma current are observed in the experiments.

  20. Benchmarking Velocity and Vorticity Measurement Systems on the UCLA Large-Scale Rotating Convection Device

    NASA Astrophysics Data System (ADS)

    Hawkins, E. K.; Aurnou, J. M.; Pilegard, T.; Grannan, A. M.; Ribeiro, A.; Cheng, J. S.; May, S.

    2015-12-01

    In order to simulate the turbulent, rapidly-rotating convection processes that occur in Earth's core and other planetary cores, we have designed and fabricated a large-scale experimental device at UCLA. Capable of accessing a broad range of parameters (e.g., Ekman numbers between E ≃ 10-2 to 10-8 and Rayleigh numbers between Ra ≃ 104 to 1013), this device is ideal for identifying new regimes of core-style convection and for determining scaling trends that can be extrapolated to planetary conditions. In particular, this device provides the opportunity to characterize the heat transfer and velocity field behaviors needed to build and test next-generation, asymptotically accurate models of rotating convection. Two experimental measurement systems, a Laser Doppler Velocimetry (LDV) and a Particle Image Velocimetry (PIV) system, have been implemented on the UCLA rotating convection device. LDV allows for the acquisition of high resolution point velocity profiles while PIV allows for the measurement of planar velocity fields using a light sheet through the fluid layer. We present results showing the strong agreement between LDV and PIV measurements. In addition, we present results of the spin up process of a homogeneous fluid that show agreement between experimental measurements, obtained through LDV, with established theory. Our present results validate the use of the LDV and PIV systems on the UCLA rotating convection device. Thus, these two systems are now calibrated to measure the velocity and vorticity fields that characterize the turbulent, rotating core-style convection that underlies dynamo generation in planetary bodies.

  1. Phase-Locked Loop Noise Reduction via Phase Detector Implementation for Single-Phase Systems

    SciTech Connect

    Thacker, Timothy; Boroyevich, Dushan; Burgos, Rolando; Wang, Fei

    2011-01-01

    A crucial component of grid-connected converters is the phase-locked loop (PLL) control subsystem that tracks the grid voltage's frequency and phase angle. Therefore, accurate fast-responding PLLs for control and protection purposes are required to provide these measurements. This paper proposes a novel feedback mechanism for single-phase PLL phase detectors using the estimated phase angle. Ripple noise appearing in the estimated frequency, most commonly the second harmonic under phase-lock conditions, is reduced or eliminated without the use of low-pass filters, which can cause delays to occur and limits the overall performance of the PLL response to dynamic changes in the system. The proposed method has the capability to eliminate the noise ripple entirely and, under extreme line distortion conditions, can reduce the ripple by at least half. Other modifications implemented through frequency feedback are shown to decrease the settling time of the PLL up to 50%. Mathematical analyses with the simulated and experimental results are provided to confirm the validity of the proposed methods.

  2. Theoretical analysis of rotating two phase detonation in a rocket motor

    NASA Technical Reports Server (NTRS)

    Shen, I.; Adamson, T. C., Jr.

    1973-01-01

    Tangential mode, non-linear wave motion in a liquid propellant rocket engine is studied, using a two phase detonation wave as the reaction model. Because the detonation wave is followed immediately by expansion waves, due to the side relief in the axial direction, it is a Chapman-Jouguet wave. The strength of this wave, which may be characterized by the pressure ratio across the wave, as well as the wave speed and the local wave Mach number, are related to design parameters such as the contraction ratio, chamber speed of sound, chamber diameter, propellant injection density and velocity, and the specific heat ratio of the burned gases. In addition, the distribution of flow properties along the injector face can be computed. Numerical calculations show favorable comparison with experimental findings. Finally, the effects of drop size are discussed and a simple criterion is found to set the lower limit of validity of this strong wave analysis.

  3. Phase transfer function of digital imaging systems

    NASA Astrophysics Data System (ADS)

    Bhakta, Vikrant R.

    For the past several decades, optical engineering has relied heavily on Fourier analysis of linear systems as a valuable aid in realizing numerous imaging applications. Today, spatial frequency analysis via the optical transfer function (OTF) remains an integral tool for the design, characterization and testing of incoherent imaging systems. The magnitude of the complex OTF is known as the modulation transfer function (MTF) and its phase is given by the phase transfer function (PTF). The MTF represents the contrast reduction at each spatial frequency; whereas, the PTF represents the spatial shift of these frequencies. While the MTF has been used extensively to characterize imaging systems, the PTF has long been ignored because it was thought to have an insignificant presence and to be difficult to understand and measure. Through theoretical analysis and experimental demonstrations, this work addresses all of these issues and shows that the PTF is a valuable tool for modern-day digital imaging systems. The effects of optical aberrations on the PTF of an imaging system in the absence of aliasing have been analyzed in detail. However, for the digital imaging systems, the effect of aliasing on the overall system behavior becomes an important consideration. To this end, the effects of aliasing on the PTF of the sampled imaging system are described and its key properties are derived. The role of PTF as an essential metric in today's imaging systems necessitates practical PTF measurement techniques. Two, easy-to-implement, image-based methods for PTF measurement are described and experimentally validated. These measurement methods and the insights gained from the theoretical analysis are leveraged for several applications spanning diverse fields such as optical system characterization, computational imaging, and image processing.

  4. The Giant Magellan Telescope phasing system

    NASA Astrophysics Data System (ADS)

    Bouchez, Antonin H.; McLeod, Brian A.; Acton, D. Scott; Kanneganti, Srikrishna; Kibblewhite, Edward J.; Shectman, Stephen A.; van Dam, Marcos A.

    2012-07-01

    The 25 m Giant Magellan Telescope consists of seven circular 8.4 m primary mirror segments with matching segmentation of the Gregorian secondary mirror. Achieving the diffraction limit in the adaptive optics observing modes will require equalizing the optical path between pairs of segments to a small fraction of the observing wavelength. This is complicated by the fact that primary mirror segments are separated by up to 40 cm, and composed of borosilicate glass. The phasing system therefore includes both edge sensors to sense high-frequency disturbances, and wavefront sensors to measure their long-term drift and sense atmosphere-induced segment piston errors. The major subsystems include a laser metrology system monitoring the primary mirror segments, capacitive edge sensors between secondary mirror segments, a phasing camera with a wide capture range, and an additional sensitive optical piston sensor incorporated into each AO instrument. We describe in this paper the overall phasing strategy, controls scheme, and the expected performance of the system with respect to the overall adaptive optics error budget. Further details may be found in specific papers on each of the subsystems.

  5. Crusader Automated Docking System Phase 3 report

    SciTech Connect

    Jatko, W.B.; Goddard, J.S.; Ferrell, R.K.; Gleason, S.S.; Hicks, J.S.; Varma, V.K.

    1996-03-01

    The US Army is developing the next generation of battlefield artillery vehicles, including an advanced, self-propelled howitzer and a companion resupply vehicle. The resupply vehicle is intended to rendezvous with the howitzer near the battlefront and to upload ammunition to the howitzer. The Army has recommended that the vehicles incorporate robotics to increase safety, by allowing the crew to remain inside their vehicles during resupply operations. Oak Ridge National Laboratory has developed an autonomous docking system for a 6-D.F. robotic, ammunition transfer arm. The docking system augments the operator`s abilities by determining the position and orientation (pose) of a docking port. The pose is the location of the x, y, and z reference axes in 3-D space; and the orientation is the rotations--roll, pitch, and yaw--about those axes. Bye precisely determining the pose of the docking port, the robot can be instructed to move to the docking position without operator intervention. The system uses a video camera and frame grabber to digitize images of the special docking port. Custom algorithms were developed to recognize the port in the camera image, to determine the pose from its image features, and to distribute the results to the robot control computer. The system is loosely coupled to the robot and can be easily adapted to different mechanical configurations. The system has successfully demonstrated autonomous docking on a 24-in. tabletop robot and a 12-ft ammunition resupply robot. The update rate, measurement accuracy, continuous operation, and accuracy with obstructed view have been determined experimentally.

  6. Asymmetric rotational axis reconstruction of grating-based x-ray phase contrast tomography of the human cerebellum

    NASA Astrophysics Data System (ADS)

    Schulz, Georg; Weitkamp, Timm; Zanette, Irene; Pfeiffer, Franz; Müller-Gerbl, Magdalena; David, Christian; Müller, Bert

    2012-10-01

    The brain has an outstanding functional importance in the human organism. Therefore, there is a strong need for three-dimensional brain imaging modalities. Magnetic resonance imaging provides deep insights but its spatial resolution is insufficient to study the structure on the cellular level. X-ray absorption microtomography yields the necessary spatial resolution, but shows only marginal contrast between the different types of brain tissue. Alternatively, differential X-ray phase contrast obtained with grating interferometry, which is known for much better differentiations between soft tissues can be used for the visualization of the human brain. As important structures of the human brain such as the human thalamus have dimensions of several centimeters, a large field of view is required. In the present communication, we report an evaluation of grating-based X-ray phase contrast microtomography in the off-axis modus which allows to expand the field of view up to a factor of two but may reduce the image quality. We demonstrate that tomograms with comparable contrast-to-noise values, about 10%, and 50% inferior spatial resolution can be generated with off-axis measurements. As one can reduce the effective pixel size up to a factor of two, the choice of an asymmetrical rotation axis can give rise to an improvement of the spatial resolution by 20%.

  7. Phase-rotation based receive-beamformer for miniaturized volumetric ultrasound imaging scanners using 2-D CMUT-on-ASIC arrays

    NASA Astrophysics Data System (ADS)

    Kim, Bae-Hyung; Lee, Seunghun; Song, Jongkeun; Kim, Youngil; Jeon, Taeho; Cho, Kyungil

    2013-03-01

    Up-to-date capacitive micromachined ultrasonic transducer (CMUT) technologies provide us unique opportunities to minimize the size and cost of ultrasound scanners by integrating front-end circuits into CMUT arrays. We describe a design prototype of a portable ultrasound scan-head probe using 2-D phased CMUT-on-ASIC arrays of 3-MHz 250 micrometer-pitch by fabricating and integrating front-end electronics with 2-D CMUT array elements. One of the objectives of our work is to design a receive beamformer architecture for the smart probe with compact size and comparable performance. In this work, a phase-rotation based receive beamformer using the sampling frequency of 4 times the center frequency and a hybrid beamforming to reduce the channel counts of the system-side are introduced. Parallel beamforming is considered for the purpose of saving power consumption of battery (by firing fewer times per image frame). This architecture has the advantage of directly obtaining I and Q components. By using the architecture, the interleaved I/Q data from the storage is acquired and I/Q demodulation for baseband processing is directly achieved without demodulators including sin and cosine lookup tables and mixers. Currently, we are extending the presented architecture to develop a true smart probe by including lower power devices and cooling systems, and bringing wireless data transmission into consideration.

  8. g--Acceleration of Gravity: Its Measurement from the Shape of Water by Using a Computerized Rotational System

    ERIC Educational Resources Information Center

    Pintao, Carlos A. F.; de Souza Filho, Moacir P.

    2007-01-01

    This paper proposes a different experimental setup compared with the traditional ones, in order to determine the acceleration of gravity, which is carried out by using a fluid at a constant rotation. A computerized rotational system--by using a data acquisition system with specific software, a power amplifier and a rotary motion sensor--is…

  9. Comparison of attached and suspended growth methanogenesis in a two phase system

    SciTech Connect

    Roy, D.; Gough, R.H.; Jones, L.M.

    1986-01-01

    Performance of an attached growth methane phase was compared to that of a completely mixed methane phase in a two-phase anaerobic process. An anaerobic rotating biological contactor (AnRBC) and a completely mixed stirred tank reactor (CSTR) were used to study the attached growth and suspended growth phase systems, respectively. In the methane phase, the hydraulic retention time (HRT) was varied from 10 to 72 hours and the pH was maintained either at 6.0 or at 7.5. The attached growth methane system was observed to be more efficient than the suspended growth methane process in methane production per gram of total organic carbon (TOC) removed.

  10. Phasing metrology system for the GMT

    NASA Astrophysics Data System (ADS)

    Acton, D. Scott; Bouchez, Antonin

    2012-09-01

    The Giant Magellan Telescope (GMT) is a 25.4 m diameter ground-based segmented Gregorian telescope, composed of 7 8.4 meter diameter primary mirror segments, and 7 1 meter diameter adaptive secondary mirror segments. Co-phasing of the integrated optical system will be partially achieved by making real-time measurements of the wavefront of an offaxis guide star. However, slowly varying aberrations due to thermal and gravitational effects, as well as wind buffeting, will make it difficult to maintain alignment using real-time optical measurements alone. Consequently, we are proposing internal metrology systems to maintain the relative alignment of the optical elements. In this paper we describe a differential capacitive edge sensing system to maintain the relative alignment of the adaptive secondary mirror reference bodies. We also propose an interferometric system for sensing of the relative displacements of primary mirror segments.

  11. [Development of rotating perfusion bioreactor system and application for bone tissue engineering].

    PubMed

    Li, Xiang; Li, Dichen; Wang, Lin; Wang, Zhen; Lu, Bingheng

    2007-02-01

    A rotating perfusion bioreactor system has recently been developed in our laboratory to produce 3D dynamic culture condition, and the critical-sized scaffolds with interconnected microchennels were fabricated. Gas exchange occurs by semipermeable membrane covered on each side of bioreactor and gas-permeable peristaltic pump tube. Rotation and perfusion of culture media through large scaffolds enhance well mixing and mass transport of oxygen and nutrients in the bioreactor. Osteoblastic cells attached to microchennels are exposed to a low fluid flow-induced shear stress level. This bioreactor system overcomes several defects exited in static culture condition, improves the culture environment, facilitates osteoblast proliferation, differntiation, significant matrix production and mineralization, and the controllability of culture process is enhanced. Large scaffolds/osteoblast constructs were cultured in the bioreactor system for 14 days. Osteoblastic cells attached to microchannels of scaffolds were observed under scanning electron microscope (SEM). The results indicated that cells grew extensively in the microchennels of large scaffolds. PMID:17333894

  12. Grazing bifurcation analysis of a relative rotation system with backlash non-smooth characteristic

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Wang, Zhao-Long; Zhao, Shuang-Shuang; Li, Hai-Bin; Li, Jian-Xiong

    2015-07-01

    Grazing bifurcation of a relative rotation system with backlash non-smooth characteristic is studied along with the change of the external excitation in this paper. Considering the oil film, backlash, time-varying stiffness and time-varying error, the dynamical equation of a relative rotation system with a backlash non-smooth characteristic is deduced by applying the elastic hydrodynamic lubrication (EHL) and the Grubin theories. In the process of relative rotation, the occurrence of backlash will lead to the change of dynamic behaviors of the system, and the system will transform from the meshing state to the impact state. Thus, the zero-time discontinuous mapping (ZDM) and the Poincare mapping are deduced to analyze the local dynamic characteristics of the system before as well as after the moment that the backlash appears (i.e., the grazing state). Meanwhile, the grazing bifurcation mechanism is analyzed theoretically by applying the impact and Floquet theories. Numerical simulations are also given, which confirm the analytical results. Project supported by the National Natural Science Foundation of China (Grant No. 61104040), the Natural Science Foundation of Hebei Province, China (Grant No. E2012203090), and the University Innovation Team of Hebei Province Leading Talent Cultivation Project, China (Grant No. LJRC013).

  13. Rotationally resolved midultraviolet studies of Triton and the Pluto/Charon system. I - IUE results

    NASA Technical Reports Server (NTRS)

    Stern, S. A.; Brosch, Noah; Barker, Edwin S.; Gladstone, G. R.

    1991-01-01

    The present uniform analysis of the full set of IUE spectra of Pluto + Charon and Triton attempts to characterize these objects' UV photometric properties variation with rotational phase, giving attention to the 2550-3200 A range. The visible-UV color differentiation increases as Pluto reaches its maximum bolometric brightness; the IUE data suggests that this could be due to a UV surface absorption feature on Pluto or Charon. Typical UV albedos are found on Triton which agree with Voyager photopolarimeter results; Pluto's albedo is much lower than that of Triton, but the amplitude of the Pluto UV lightcurve is greater than that of Triton.

  14. The change of rotational freedom following different insertion torques in three implant systems with implant driver

    PubMed Central

    Kwon, Joo-Hyun; Han, Chong-Hyun; Chang, Jae-Seung

    2009-01-01

    STATEMENT OF PROBLEM Implant drivers are getting popular in clinical dentistry. Unlike to implant systems with external hex connection, implant drivers directly engage the implant/abutment interface. The deformation of the implant/abutment interface can be introduced while placing an implant with its implant driver in clinical situations. PURPOSE This study evaluated the change of rotational freedom between an implant and its abutment after application of different insertion torques. MATERIAL AND METHODS Three kinds of internal connection implants were utilized for the current study (4.5 × 12 mm Xive, 4.3 × 11.5 mm Inplant Magicgrip, 4.3 × 12 mm Implantium MF). An EstheticBase, a 2-piece top, a Dual abutment was used for its corresponding implant system. The rotational freedom between an implant and its abutment were measured before and after applying 45, 100 Ncm insertion torque. Repeated measures ANOVA was used for statistical analysis. RESULTS Under 45 Ncm insertion torque, the rotational freedom between an implant and its abutment was significantly increased in Xive (P = .003). However, no significant change was noted in Inplant Magicgrip and Implantium MF. Under 100 Ncm torque, both in Xive (P = .0005) and Implatium MF (P = .03) resulted in significantly increased rotational freedom between the implant and its abutment. DISCUSSION The design of the implant/implant driver interface effectively prevented the deformation of implant/abutment interface. Little change was noted in the rotational freedom between an implant and its abutment, even though the insertion torque was far beyond clinical application. CONCLUSIONS The implant/abutment joint of internally connecting implants were quite stable under insertion torque in clinical situation. PMID:21165253

  15. Regression Test on the Rotational Speed between Two Loads as the Preparation for Braking System

    NASA Astrophysics Data System (ADS)

    Purwanti, B. S. R.; Yusivar, F.; K, I. Garniwa M.

    2013-04-01

    This paper is preparing the mathematic model of braking control, continuously of determination the error (e), delta error (de) of speed reduction [9]. Load-1 and Load-2 are driven by an electric motor located on the same shaft. Both loads are driven clock wise (CW), counter clock wise (CCW) by an asynchronous three-phase motor (M3). The mass of each load is also differentiated to simulate slip phenomena. Rotational speed of M3 is equal to Load-1, detected by Sensor-1, while speed rotation of Load-2 is detected by Sensor-2. The rotation for Load-1 and Load-2 can be adjusted on several position Hj (j = 1, 2, 3). Once Load-1 and Load-2 reach a constant speed, current source will be disconnected. Speed reduction from (ω±1475 rpm) to stagnant (ω=0 rpm) on Load-1 and Load-2 is considered time function. Data collected from both load (ω (t)) known as e, de; on each position of Hj. It uses covariance analysis to make sure that both loads are concurrent with each other against time difference. The objective of this research is to determine slip phenomena of speed reduction of each load. The expectations are to generate smoother braking and minimize the time needed when implemented with ANFIS.

  16. Optical fibre resonator rotation sensor using a low coherence source

    NASA Astrophysics Data System (ADS)

    Farhadiroushan, M.; Giles, I. P.; Youngquist, R. C.

    1987-03-01

    A resonator-type rotation sensor using a low coherence is presented. While the system uses phase modulation techniques similar to those of the conventional optical fiber gyroscope, it relies on multiple loop transitions to enhance system sensitivity. The theoretical rotation sensitivity is 2.7 times greater than that of the conventional phase-modulated Sagnac interferometer. Consideration is given to the phase-induced intensity noise in the system.

  17. Rotationally driven Fragmentation in the Formation of the Binary Protostellar System L1551 IRS 5

    NASA Astrophysics Data System (ADS)

    Lim, Jeremy; Yeung, Paul K. H.; Hanawa, Tomoyuki; Takakuwa, Shigehisa; Matsumoto, Tomoaki; Saigo, Kazuya

    2016-08-01

    Both bulk rotation and local turbulence have been widely suggested to drive the fragmentation in collapsing cores that produces multiple star systems. Even when the two mechanisms predict different alignments for stellar spins and orbits, subsequent internal or external interactions can drive multiple systems toward or away from alignment, thus masking their formation processes. Here, we demonstrate that the geometrical and dynamical relationship between a binary system and its surrounding bulk envelope provide the crucial distinction between fragmentation models. We find that the circumstellar disks of the binary protostellar system L1551 IRS 5 are closely parallel, not just with each other but also with their surrounding flattened envelope. Measurements of the relative proper motion of the binary components spanning nearly 30 years indicate an orbital motion related to that of the envelope rotation. Eliminating orbital solutions whereby the circumstellar disks would be tidally truncated to sizes smaller than observed, the remaining solutions favor a circular or low-eccentricity orbit tilted by up to ˜25° from the circumstellar disks. Turbulence-driven fragmentation can generate local angular momentum to produce a coplanar binary system, but this would have no particular relationship to the system’s surrounding envelope. Instead, the observed properties conform with predictions for rotationally driven fragmentation. If the fragments were produced at different heights or on opposite sides of the mid-plane in the flattened central region of a rotating core, the resulting protostars would then exhibit circumstellar disks parallel with the surrounding envelope but tilted from the orbital plane, as is observed.

  18. Computation of fluid flow and heat transfer in rotating disc-systems

    NASA Astrophysics Data System (ADS)

    Ong, Chew-Lan

    Described here is a numerical investigation into the turbulent flow and heat transfer characteristics in rotating disc systems. Particular emphasis has been given to the study of a rotating cylindrical cavity with a radial outflow of fluid which provides a simple model of the flow between two corotating air-cooled gas-turbine discs. Study is also made of the free disc, a single disc rotating in an infinite quiescent environment. The main effort has been devoted to the development and application of a suite of computer programs for the solution of the momentum and energy equations governing the highly-skewed boundary layers on the discs, for both incompressible and compressible flows. An accurate and efficient solution procedure has been devised, based on the Keller-Box finite-difference scheme, and a noniterative method for the determination of the pressure field implemented. Serious numerical problems associated with the reverse flows in the nonentraining Ekman-type layer have been successfully overcome. Turbulence has been modelled using both isotropic and anisotropic eddy-viscosity/mixing-length formulations, the use of a low-Reynolds-number k-epsilon turbulence model proving unsatisfactory. Predictions of the velocity distributions inside the Ekman layer and in the inviscid core of the rotating cavity have been compared with extensive laser-Doppler-anemometry measurements.

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

    PubMed Central

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

    2015-01-01

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

  20. Fiber optic sensor system for detecting movement or position of a rotating wheel bearing

    DOEpatents

    Veeser, Lynn R.; Rodriguez, Patrick J.; Forman, Peter R.; Monahan, Russell E.; Adler, Jonathan M.

    1997-01-01

    An improved fiber optic sensor system and integrated sensor bearing assembly for detecting movement or position of a rotating wheel bearing having a multi-pole tone ring which produces an alternating magnetic field indicative of movement and position of the rotating member. A magneto-optical material, such as a bismuth garnet iron (B.I.G.) crystal, having discrete magnetic domains is positioned in the vicinity of the tone ring so that the domains align themselves to the magnetic field generated by the tone ring. A single fiber optic cable, preferably single mode fiber, carries light generated by a source of light to the B.I.G. crystal. The light passes through the B.I.G. crystal and is refracted at domain boundaries in the crystal. The intensity of the refracted light is indicative of the amount of alignment of the domains and therefore the strength of the magnetic field. The refracted light is carried by the fiber optic cable to an optic receiver where the intensity is measured and an electrical signal is generated and sent to a controller indicating the frequency of the changes in light intensity and therefore the rotational speed of the rotating wheel bearing.

  1. Intelligent Robotic Systems Study (IRSS), phase 4

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Under the Intelligent Robotics Systems Study (IRSS), a generalized robotic control architecture was developed for use with the ProtoFlight Manipulator Arm (PFMA). Based upon the NASREM system design concept, the controller built for the PFMA provides localized position based force control, teleoperation, and advanced path recording and playback capabilities. The PFMA has six computer controllable degrees of freedom (DOF) plus a 7th manually indexable DOF, making the manipulator a pseudo 7 DOF mechanism. Joints on the PFMA are driven via 7 pulse width modulated amplifiers. Digital control of the PFMA is implemented using a variety of single board computers. There were two major activities under the IRSS phase 4 study: (1) enhancement of the PFMA control system software functionality; and (2) evaluation of operating modes via a teleoperation performance study. These activities are described and results are given.

  2. Rotating Casimir systems: Magnetic-field-enhanced perpetual motion, possible realization in doped nanotubes, and laws of thermodynamics

    NASA Astrophysics Data System (ADS)

    Chernodub, M. N.

    2013-01-01

    Recently, we have demonstrated that for a certain class of Casimir-type systems (“devices”) the energy of zero-point vacuum fluctuations reaches its global minimum when the device rotates about a certain axis rather than remains static. This rotational vacuum effect may lead to the emergence of permanently rotating objects provided the negative rotational energy of zero-point fluctuations cancels the positive rotational energy of the device itself. In this paper, we show that for massless electrically charged particles the rotational vacuum effect should be drastically (astronomically) enhanced in the presence of a magnetic field. As an illustration, we show that in a background of experimentally available magnetic fields the zero-point energy of massless excitations in rotating torus-shaped doped carbon nanotubes may indeed overwhelm the classical energy of rotation for certain angular frequencies so that the permanently rotating state is energetically favored. The suggested “zero-point-driven” devices—which have no internally moving parts—correspond to a perpetuum mobile of a new, fourth kind: They do not produce any work despite the fact that their equilibrium (ground) state corresponds to a permanent rotation even in the presence of an external environment. We show that our proposal is consistent with the laws of thermodynamics.

  3. Dual annular rotating [open quotes]windowed[close quotes] nuclear reflector reactor control system

    DOEpatents

    Jacox, M.G.; Drexler, R.L.; Hunt, R.N.M.; Lake, J.A.

    1994-03-29

    A nuclear reactor control system is provided in a nuclear reactor having a core operating in the fast neutron energy spectrum where criticality control is achieved by neutron leakage. The control system includes dual annular, rotatable reflector rings. There are two reflector rings: an inner reflector ring and an outer reflector ring. The reflectors are concentrically assembled, surround the reactor core, and each reflector ring includes a plurality of openings. The openings in each ring are capable of being aligned or non-aligned with each other. Independent driving means for each of the annular reflector rings is provided so that reactor criticality can be initiated and controlled by rotation of either reflector ring such that the extent of alignment of the openings in each ring controls the reflection of neutrons from the core. 4 figures.

  4. Unbalance Identification and Field Balancing of Dual Rotors System with Slightly Different Rotating Speeds

    NASA Astrophysics Data System (ADS)

    Zeng, S.; Wang, X.-X.

    1999-02-01

    The identification of unbalance is the crux of field balancing of dual rotors system with slightly different rotating speeds. On the basis of correlation theory, this paper explains a method called “Single Point Discrete Fourier Transformation (DFT)” to identify the unbalance. By theoretical analysis, the correlation integral time and its maximum possible error are determined. The field balancing experiment on WLZY-350 horizontal spiral centrifuge verifies its precision, reliability and applicability in practice.

  5. Testing of the line element of special relativity with rotating systems

    NASA Technical Reports Server (NTRS)

    Vargas, Jose G.; Torr, Douglas G.

    1989-01-01

    Experiments with rotating systems are examined from the point of view of a test theory of the Lorentz transformations (LTs), permitting, in principle, the verification of the simultaneity relation. The significance of the experiments involved in the testing of the LTs can be determined using Robertson's test theory (RTT). A revised RTT is discussed, and attention is given to the Ehrenfest paradox in connection with the testing of the LTs.

  6. Elucidating the role of aromatic interactions in rotational barriers involving aromatic systems.

    PubMed

    Lima, Carlos F R A C; Gomes, Lígia R; Low, John N; Silva, Artur M S; Santos, Luís M N B F

    2012-11-16

    The measurement of aryl-naphthyl rotational barriers, ΔG(⧧), in various solvents for two substituted 1,8-diarylnaphthalenes by dynamic (1)H NMR showed that ΔG(‡) trends in aromatic systems can be fully rationalized only when considering the different types of aromatic interactions that can be established in the ground and transition states, namely, intramolecular interactions involving the aromatic rings and specific solvation interactions. PMID:23106141

  7. Phase behavior of semiflexible polymer systems

    NASA Astrophysics Data System (ADS)

    Moonay, David Jordan

    Phase behavior of semiflexible poly(n-hexyl isocyanate) (PHIC) and flexible coil poly(cyclohexyl methacrylate) (PCHMA) were investigated. Room-temperature solubility screenings showed that PCHMA behavior in various solvents agreed with that predicted by Flory-Huggins theory: solvents had interaction parameter values chi1 < 0.5, i.e., less than the critical value for incipient phase separation, while nonsolvents had chi1 > 1, well within the thermodynamically-poor solvency region. PHIC, on the other hand, had interactions which were not in accord with the simple enthalpic theory. A high-boiling solvent, 1-chloronaphthalene, was chosen as suitable for binary and ternary phase behavior work, as a result of the screenings. PCHMA was found to be soluble at all concentrations at room temperature. However, PHIC crystallized at about 5 wt.% a result not previously reported in the literature. The crystallinity, and degradation, interfered with liquid crystalline expression up to the PHIC melting point in binary solution. The novel room-temperature ternary phase diagram, PHIC/PCHMA/CLN, was developed. Particularly striking is its 5 wt.% total polymer solubility limit, which extended to 90:1 (w/w) ratios of PCHMA:PI-HC in CLN, as verified by serial dilution experiments. Novel gels were prepared with PHIC longer-pendant-group homologs poly(n-nonylisocyanate) and poly(n-undecylisocyanate), to investigate their heightened solubility relative to PHIC, in high-boiling alkylaromatic solvents. Apparently homogeneous isotropic gels in two structurally similar solvents, were found. Lengthening pendant groups in the alkyl isocyanate polymers increases solubility in high-boiling solvents, although gelation occurs when the solutions are cooled to room temperature. Elongational flow apparati were constructed. Trumpet-shaped tube experiments indicated no flow-induced crystallinity of isotropic PHIC/CLN solutions. A planar-elongational flow system was constructed and tested, and its central

  8. Feed-forward digital phase and amplitude correction system

    DOEpatents

    Yu, David U. L.; Conway, Patrick H.

    1994-01-01

    Phase and amplitude modifications in repeatable RF pulses at the output of a high power pulsed microwave amplifier are made utilizing a digital feed-forward correction system. A controlled amount of the output power is coupled to a correction system for processing of phase and amplitude information. The correction system comprises circuitry to compare the detected phase and amplitude with the desired phase and amplitude, respectively, and a digitally programmable phase shifter and attenuator and digital logic circuitry to control the phase shifter and attenuator. The Phase and amplitude of subsequent are modified by output signals from the correction system.

  9. Feed-forward digital phase and amplitude correction system

    DOEpatents

    Yu, D.U.L.; Conway, P.H.

    1994-11-15

    Phase and amplitude modifications in repeatable RF pulses at the output of a high power pulsed microwave amplifier are made utilizing a digital feed-forward correction system. A controlled amount of the output power is coupled to a correction system for processing of phase and amplitude information. The correction system comprises circuitry to compare the detected phase and amplitude with the desired phase and amplitude, respectively, and a digitally programmable phase shifter and attenuator and digital logic circuitry to control the phase shifter and attenuator. The phase and amplitude of subsequent are modified by output signals from the correction system. 11 figs.

  10. A Two Fiber Bragg Gratings Sensing System to Monitor the Torque of Rotating Shaft.

    PubMed

    Wang, Yongjiao; Liang, Lei; Yuan, Yinquan; Xu, Gang; Liu, Fang

    2016-01-01

    By fixing two FBGs on the surface of a rotating shaft along the direction of ± 45° and using dynamic wavelength demodulation technology, we propose an optical fiber sensing system to monitor the driving torque and torsion angle of the rotating shaft. In theory, the dependence relation of the dynamic difference of central wavelengths on the torque and torsion angle of the rotating shaft has been deduced. To verify an optical fiber sensing system, a series of sensing experiments have been completed and the measured data are approximately consistent with the theoretical analysis. The difference of two central wavelengths can be expressed as the sum of two parts: a "DC" part and a harmonic "AC" part. The driving torque or torsion angle is linear with the "DC" part of the difference of two central wavelengths, the harmonic "AC" part, meaning the torsion angle vibration, illustrates that periodic vibration torque may be caused by inhomogeneous centrifugal forces or inhomogeneous additional torques produced by the driving system and the load. PMID:26805843

  11. Bilateral control-based compensation for rotation in imaging in scan imaging systems

    NASA Astrophysics Data System (ADS)

    Tian, Dapeng; Wang, Yutang; Wang, Fuchao; Zhang, Yupeng

    2015-12-01

    Scan imaging systems rely on the rotation of a mirror to scan an image. The rotation in the resulting image must be compensated to prevent information loss. Satisfactory performance of an imaging system is difficult to achieve when employing the methods of mechanical transmission and unilateral tracking control, especially when the system suffers from nonlinear factors, disturbances, and dynamic uncertainties. This paper proposes a compensation method based on bilateral control derived from the field of haptic robots. A two-loop disturbance observer was designed to guarantee that the dynamic characteristics of the motor are close to those of the nominal model. The controllers were designed on the basis of the small gain theorem. Experiments were conducted for a comparison with the traditional unilateral control-based compensation. The comparison showed a reduction of 99.83% in the L2 norm of error, which validates the method. The proposed method improves the accuracy of compensation for rotation in imaging, and demonstrates that bilateral control has feasibility for application in various fields, including photogrammetry.

  12. A Two Fiber Bragg Gratings Sensing System to Monitor the Torque of Rotating Shaft

    PubMed Central

    Wang, Yongjiao; Liang, Lei; Yuan, Yinquan; Xu, Gang; Liu, Fang

    2016-01-01

    By fixing two FBGs on the surface of a rotating shaft along the direction of ±45° and using dynamic wavelength demodulation technology, we propose an optical fiber sensing system to monitor the driving torque and torsion angle of the rotating shaft. In theory, the dependence relation of the dynamic difference of central wavelengths on the torque and torsion angle of the rotating shaft has been deduced. To verify an optical fiber sensing system, a series of sensing experiments have been completed and the measured data are approximately consistent with the theoretical analysis. The difference of two central wavelengths can be expressed as the sum of two parts: a “DC” part and a harmonic “AC” part. The driving torque or torsion angle is linear with the “DC” part of the difference of two central wavelengths, the harmonic “AC” part, meaning the torsion angle vibration, illustrates that periodic vibration torque may be caused by inhomogeneous centrifugal forces or inhomogeneous additional torques produced by the driving system and the load. PMID:26805843

  13. Analysis of a planetary-rotation system for evaporated optical coatings

    SciTech Connect

    Oliver, J. B.

    2016-01-01

    The impact of planetary-design considerations for optical coating deposition is analyzed, including the ideal number of planets, variations in system performance, and the deviation of planet motion from the ideal. System capacity is maximized for four planets, although substrate size can significantly influence this result. Guidance is provided in the design of high-performance deposition systems based on the relative impact of different error modes. As a result, errors in planet mounting such that the planet surface is not perpendicular to its axis of rotation are particularly problematic, suggesting planetary design modifications would be appropriate.

  14. Investigation of the gas-phase structure and rotational barrier of trimethylsilyl trifluoromethanesulfonate and comparison with covalent sulfonates

    NASA Astrophysics Data System (ADS)

    Defonsi Lestard, María E.; Tuttolomondo, María E.; Varetti, Eduardo L.; Wann, Derek A.; Robertson, Heather E.; Rankin, David W. H.; Altabef, Aida Ben

    2010-12-01

    The molecular structure of trimethylsilyl trifluoromethanesulfonate, CF 3SO 2OSi(CH 3) 3, has been determined in the gas phase from electron-diffraction data supplemented by ab initio (MP2) and DFT calculations using 6-31G(d), 6-311++G(d,p) and 6-311G++(3df,3pd) basis sets. Both experimental and theoretical data indicate that only one gauche conformer is possible by rotating about the O-S bond. The anomeric effect is a fundamental stereoelectronic interaction and presents a profound influence on the electronic geometry. We have investigated the origin of the anomeric effect by means of NBO and AIM analysis. A natural bond orbital analysis showed that the lpπ[O bonded to Si)] → σ *[C-S] hyperconjugative interaction favors the gauche conformation. In addition, comparison of the structural and stereoelectronic properties of the title molecule with those of silyl trifluoromethanesulfonate and methyl trifluoromethanesulfonate has been carried out.

  15. Gas Phase Raman Spectra of Butadiene and BUTADIENE-d_{6} and the Internal Rotation Potential Energy Function

    NASA Astrophysics Data System (ADS)

    Boopalachandran, Praveenkumar; Laane, Jaan; Craig, Norman C.

    2009-06-01

    The Raman spectrum of butadiene has been previously reported by Carreira and by Engeln and co-workers. Both studies reported a series of bands corresponding to double quantum jumps of ν_{13}, the internal rotation vibration, of the trans rotamer. Both studies also reported weaker bands assigned to the higher energy conformer. Carriera assigned these to the cis form while Engeln assigned them to the gauche form. Recent high level calculations by Feller and Craig also assign the higher energy form as gauche. In the present study we report the gas phase Raman spectrum of butadiene and its d_{6} isotopomer at both 25^°C and 260^°C. Several new spectral features in the 330 to 210 cm^{-1} region were observed and the effect of heating on the band intensities was studied. In addition, combination bands were observed in the 630 to 690 cm^{-1} (ν_{12} + ν_{13}) and 1130 to 1180 cm^{-1} (ν_{10} + ν_{13}) regions. A periodic potential energy function with V_{1}, V_{2}, V_{3}, V_{4}, and V_{6} terms was utilized to fit the data. This function was compared to the results from previous work and to the theoretical calculation. L. Carreira, J. Phys. Chem. 62, 3851 (1975). R. Engeln, D. Consalvo, and J. Reuss, J. Chem. Phys. 160, 427 (1992). D. Feller and N. C. Craig, J. Phys. Chem. 113, 1601 (2009).

  16. Solar system constraints on planetary Coriolis-type effects induced by rotation of distant masses

    SciTech Connect

    Iorio, Lorenzo

    2010-08-01

    We phenomenologically put local constraints on the rotation of distant masses by using the planets of the solar system. First, we analytically compute the orbital secular precessions induced on the motion of a test particle about a massive primary by a Coriolis-like force, treated as a small perturbation, in the case of a constant angular velocity vector Ψ directed along a generic direction in space. The semimajor axis a and the eccentricity e of the test particle do not secularly change, contrary to the inclination I, the longitude of the ascending node Ω, the longitude of the pericenter varpi and the mean anomaly M. Then, we compare our prediction for (dot varpi) with the corrections Δdot varpi to the usual perihelion precessions of the inner planets recently estimated by fitting long data sets with different versions of the EPM ephemerides. We obtain as preliminary upper bounds |Ψ{sub z}| ≤ 0.0006−0.013 arcsec cty{sup −1}, |Ψ{sub x}| ≤ 0.1−2.7 arcsec cty{sup −1}, |Ψ{sub y}| ≤ 0.3−2.3 arcsec cty{sup −1}. Interpreted in terms of models of space-time involving cosmic rotation, our results are able to yield constraints on cosmological parameters like the cosmological constant Λ and the Hubble parameter H{sub 0} not too far from their values determined with cosmological observations and, in some cases, several orders of magnitude better than the constraints usually obtained so far from space-time models not involving rotation. In the case of the rotation of the solar system throughout the Galaxy, occurring clockwise about the North Galactic Pole, our results for Ψ{sub z} are in disagreement with the expected value of it at more than 3−σ level. Modeling the Oort cloud as an Einstein-Thirring slowly rotating massive shell inducing Coriolis-type forces inside yields unphysical results for its putative rotation.

  17. [N2O emission from rice-rapeseed rotation system in Chengdu Plain of Sichun Basin].

    PubMed

    Yu, Ya-Jun; Zhu, Bo; Wang, Xiao-Guo; Xiang, Hong-Yan; Zheng, Xun-Hua

    2008-06-01

    By using static chamber/gas chromatograph techniques, the N2O emission from rice-rapeseed rotation system in Chengdu Plain of Sichuan Basin was measured from June 2005 to June 2006, with its characteristics and affecting factors investigated. The results showed that the total emission of N2O in a rotation cycle was (8.3 +/- 2.8) kg x hm(-2) x a(-1), and the emission in rice season, rapeseed season and fallow season accounted for 30%, 65%, and 5% of the total, respectively. In rice season, the mean N2O flux was higher during alternative drainage and irrigation than during continuous flooding and drainage, and was roughly the same during continuous flooding and drainage. N application was the main driving factor for the appearance of N2O emission peak, and the lower moisture content in surface soil layer in rapeseed season and fallow season was the main cause inducing soil N2O absorption. Soil moisture, soil temperature, N application, and crop involvement affected the N2O emission to various extents, and soil moisture was the key factor affecting the N2O emission. To avoid the high frequency of dry and wet alternation in rice season or to regulate soil moisture content to a level of 50%-70% WFPS (percentage of water-filled pore space) in rapeseed season and fallow season could effectively decrease the N2O emission from the rice-rapeseed rotation system.

  18. A 100-W grade closed-cycle thermosyphon cooling system used in HTS rotating machines

    NASA Astrophysics Data System (ADS)

    Felder, Brice; Miki, Motohiro; Tsuzuki, Keita; Shinohara, Nobuyuki; Hayakawa, Hironao; Izumi, Mitsuru

    2012-06-01

    The cooling systems used for rotating High-Temperature Superconducting (HTS) machines need a cooling power high enough to ensure a low temperature during various utilization states. Radiation, torque tube or current leads represent hundreds of watts of invasive heat. The architecture also has to allow the rotation of the refrigerant. In this paper, a free-convection thermosyphon using two Gifford-McMahon (GM) cryocoolers is presented. The cryogen is mainly neon but helium can be added for an increase of the heat transfer coefficient. The design of the heat exchangers was first optimized with FEM thermal analysis. After manufacture, they were assembled for preliminary experiments and the necessity of annealing was studied for the copper parts. A single evaporator was installed to evaluate the thermal properties of such a heat syphon. The maximum bearable static heat load was also investigated, but was not reached even at 150 W of load. Finally, this cooling system was tested in the cooling down of a 100-kW range HTS rotating machine containing 12 Bi-2223 double-pancake coils (DPC).

  19. A novel parallel-rotation algorithm for atomistic Monte Carlo simulation of dense polymer systems

    NASA Astrophysics Data System (ADS)

    Santos, S.; Suter, U. W.; Müller, M.; Nievergelt, J.

    2001-06-01

    We develop and test a new elementary Monte Carlo move for use in the off-lattice simulation of polymer systems. This novel Parallel-Rotation algorithm (ParRot) permits moving very efficiently torsion angles that are deeply inside long chains in melts. The parallel-rotation move is extremely simple and is also demonstrated to be computationally efficient and appropriate for Monte Carlo simulation. The ParRot move does not affect the orientation of those parts of the chain outside the moving unit. The move consists of a concerted rotation around four adjacent skeletal bonds. No assumption is made concerning the backbone geometry other than that bond lengths and bond angles are held constant during the elementary move. Properly weighted sampling techniques are needed for ensuring detailed balance because the new move involves a correlated change in four degrees of freedom along the chain backbone. The ParRot move is supplemented with the classical Metropolis Monte Carlo, the Continuum-Configurational-Bias, and Reptation techniques in an isothermal-isobaric Monte Carlo simulation of melts of short and long chains. Comparisons are made with the capabilities of other Monte Carlo techniques to move the torsion angles in the middle of the chains. We demonstrate that ParRot constitutes a highly promising Monte Carlo move for the treatment of long polymer chains in the off-lattice simulation of realistic models of dense polymer systems.

  20. A Multidirectional Tribo-System: Wear of UHMWPE under Sliding, Rolling, and Rotation

    NASA Astrophysics Data System (ADS)

    Patten, Elias Wolfgang

    Total knee replacements (TKR) have become a successful surgical procedure for addressing end-stage osteoarthritis, with ultra-high molecular weight polyethylene and cobalt chrome alloy (UHMWPE/Co-Cr) serving as the bearing materials of choice for decades. However, more than 10% of TKRs fail and require revision surgery. The predominant challenge with UHMWPE is the particulate debris generated through wear-mediated processes; wear debris from the UHMWPE tibial bearing surface leading to loosening is still the main cause for post-fifth-year revisions. UHMWPE wear in hip arthroplasty has been linked to microstructural evolution at the surface from multidirectional sliding in the hip joint but little is known about how the microstructure responds to clinically relevant sliding conditions in the knee. This is likely because wear tests are typically performed under basic motion parameters with simplified geometry (pin-on-disk tests) while the knee has more complex kinematics: it is neither a ball-and-socket joint nor a simple hinge joint, but has 2D sliding, rolling/slip motion, and rotation. There is also disagreement over how to best quantify cross-shear and how to model how much wear it will cause. A custom multidirectional tribo-system was used to investigate the individual and combined effects of the different motions in TKR: 2D sliding, rolling, and rotation, for a total of eight separate kinematic conditions. The trends in wear rates and wear factors for these different motions were compared with many different definitions for magnitudes and ratios of cross-shear. Additionally, the wear surfaces were examined for wear mechanism and the microstructural changes in lamellae orientation for the different motions were analyzed. To mimic the tribological conditions of a condyle in a TKR, polished Co-Cr spheres were articulated against flat, smooth UHMWPE disks with physiologically relevant loading, speed, and lubrication conditions. The motion parameters were selected

  1. A Multidirectional Tribo-System: Wear of UHMWPE under Sliding, Rolling, and Rotation

    NASA Astrophysics Data System (ADS)

    Patten, Elias Wolfgang

    Total knee replacements (TKR) have become a successful surgical procedure for addressing end-stage osteoarthritis, with ultra-high molecular weight polyethylene and cobalt chrome alloy (UHMWPE/Co-Cr) serving as the bearing materials of choice for decades. However, more than 10% of TKRs fail and require revision surgery. The predominant challenge with UHMWPE is the particulate debris generated through wear-mediated processes; wear debris from the UHMWPE tibial bearing surface leading to loosening is still the main cause for post-fifth-year revisions. UHMWPE wear in hip arthroplasty has been linked to microstructural evolution at the surface from multidirectional sliding in the hip joint but little is known about how the microstructure responds to clinically relevant sliding conditions in the knee. This is likely because wear tests are typically performed under basic motion parameters with simplified geometry (pin-on-disk tests) while the knee has more complex kinematics: it is neither a ball-and-socket joint nor a simple hinge joint, but has 2D sliding, rolling/slip motion, and rotation. There is also disagreement over how to best quantify cross-shear and how to model how much wear it will cause. A custom multidirectional tribo-system was used to investigate the individual and combined effects of the different motions in TKR: 2D sliding, rolling, and rotation, for a total of eight separate kinematic conditions. The trends in wear rates and wear factors for these different motions were compared with many different definitions for magnitudes and ratios of cross-shear. Additionally, the wear surfaces were examined for wear mechanism and the microstructural changes in lamellae orientation for the different motions were analyzed. To mimic the tribological conditions of a condyle in a TKR, polished Co-Cr spheres were articulated against flat, smooth UHMWPE disks with physiologically relevant loading, speed, and lubrication conditions. The motion parameters were selected

  2. Joint robustness security in optical OFDM access system with Turbo-coded subcarrier rotation.

    PubMed

    Zhang, Lijia; Liu, Bo; Xin, Xiangjun; Wang, Yongjun

    2015-01-12

    This paper proposes a novel robust physical secure method for optical orthogonal frequency division multiplexing (OFDM) access system based on Turbo-coded subcarrier rotation. It can realize a secure communication while keep robustness to channel noise. The subcarrier rotation is controlled by the interleaver module of Turbo coding, which is under the charge of Logistic map. The random puncturing can further enhance the security. The channel feedback can ensure the puncturing module working at a suitable coding rate. A 72.28 Gb/s encrypted 16QAM-OFDM signal is successfully demonstrated in the experiment. The results show robust performance under different channel noise conditions and good resistance to illegal optical network unit (ONU).

  3. Tidal friction and generalized Cassini's laws in the solar system. [for planetary spin axis rotation

    NASA Technical Reports Server (NTRS)

    Ward, W. R.

    1975-01-01

    The tidal drift toward a generalized Cassini state of rotation of the spin axis of a planet or satellite in a precessing orbit is described. Generalized Cassini's laws are applied to several solar system objects and the location of their spin axes estimated. Of those considered only the moon definitely occupies state 2 with the spin axis near to the normal of the invariable plane. Most objects appear to occupy state 1 with the spin axis near to the orbit normal. Iapetus could occupy either state depending on its oblateness. In addition, the resonant rotation of Mercury is found to have little effect on the tidal drift of its spin axis toward state 1.

  4. Development of the High Field Magneto-Optical Measurement System with a Rotational Cavity for the Study of Organic Conductors

    NASA Astrophysics Data System (ADS)

    Kimata, M.; Ohta, H.; Koyama, K.; Oshima, Y.; Motokawa, M.; Yamamoto, H. M.; Kato, R.

    2005-04-01

    We have developed a new magneto-optical measurement system with a rotational cavity. It consists of a millimeter vector network analyzer and a 15T solenoid type superconducting magnet and it can go down to 1.5 K. The rotational cavity can be used in the transmission configuration and the rotation can be performed up to almost 360 degrees in 1 degree precision. We will show the magneto-optical measurement results of β"-(BEDT-TTF)(TCNQ) using our new system. We observe the quasi-two-dimensional periodic orbit resonance (POR) in β"-(BEDT-TTF)(TCNQ). The Fermi surfaces of this system will be discussed.

  5. Development of the High Field Magneto-Optical Measurement System with a Rotational Cavity for the Study of Organic Conductors

    NASA Astrophysics Data System (ADS)

    Kimata, M.; Ohta, H.; Koyama, K.; Oshima, Y.; Motokawa, M.; Yamamoto, H. M.; Kato, R.

    We have developed a new magneto-optical measurement system with a rotational cavity. It consists of a millimeter vector network analyzer and a 15T solenoid type superconducting magnet and it can go down to 1.5 K. The rotational cavity can be used in the transmission configuration and the rotation can be performed up to almost 360 degrees in 1 degree precision. We will show the magneto-optical measurement results of β"-(BEDT-TTF)(TCNQ) using our new system. We observe the quasi-two-dimensional periodic orbit resonance (POR) in β"-(BEDT-TTF) (TCNQ). The Fermi surfaces of this system will be discussed.

  6. An infinitely-stiff elastic system via a tuned negative-stiffness component stabilized by rotation-produced gyroscopic forces

    NASA Astrophysics Data System (ADS)

    Kochmann, D. M.; Drugan, W. J.

    2016-06-01

    An elastic system containing a negative-stiffness element tuned to produce positive-infinite system stiffness, although statically unstable as is any such elastic system if unconstrained, is proved to be stabilized by rotation-produced gyroscopic forces at sufficiently high rotation rates. This is accomplished in possibly the simplest model of a composite structure (or solid) containing a negative-stiffness component that exhibits all these features, facilitating a conceptually and mathematically transparent, completely closed-form analysis.

  7. Nonquantized dirac monopoles and strings in the berry phase of anisotropic spin systems.

    PubMed

    Bruno, Patrick

    2004-12-10

    The Berry phase of an anisotropic spin system that is adiabatically rotated along a closed circuit C is investigated. It is shown that the Berry phase consists of two contributions: (i) a geometric contribution which can be interpreted as the flux through C of a nonquantized Dirac monopole, and (ii) a topological contribution which can be interpreted as the flux through C of a Dirac string carrying a nonquantized flux, i.e., a spin analogue of the Aharonov-Bohm effect. Various experimental consequences of this novel effect are discussed. PMID:15697856

  8. Maintaining rotational equilibrium during object manipulation: linear behavior of a highly non-linear system

    PubMed Central

    Gao, Fan; Latash, Mark L.

    2010-01-01

    We address issues of simultaneous control of the grasping force and the total moment of forces applied to a handheld object during its manipulation. Six young healthy male subjects grasped an instrumented handle and performed its cyclic motion in the vertical direction. The handle allowed for setting different clockwise (negative) or counterclockwise torques. Three movement frequencies: 1, 1.5 and 2 Hz, and five different torques: −1/3, −1/6, 0, 1/6 and 1/3 Nm, were used. The rotational equilibrium was maintained by two means: (1) Concerted changes of the moments produced by the normal and tangential forces, specifically anti-phase changes of the moments during the tasks with zero external torque and in-phase changes during the non-zero-torque tasks, and (2) Redistribution of the normal forces among individual fingers such that the agonist fingers—the fingers that resist external torque—increased the force in phase with the acceleration, while the forces of the antagonist fingers—those that assist the external torque—especially, the fingers with the large moment arms, the index and little fingers, stayed unchanged. The observed effects agree with the principle of superposition—according to which some complex actions, for example, prehension, can be decomposed into elemental actions controlled independently—and the mechanical advantage hypothesis according to which in moment production the fingers are activated in proportion to their moment arms with respect to the axis of rotation. We would like to emphasize the linearity of the observed relations, which was not prescribed by the task mechanics and seems to be produced by specific neural control mechanisms. PMID:16328302

  9. Method for correction of rotation errors in Micro-CT System

    NASA Astrophysics Data System (ADS)

    Zhao, Jintao; Hu, Xiaodong; Zou, Jing; Zhao, Gengyan; Lv, Hanyu; Xu, Linyan; Xu, Ying; Hu, Xiaotang

    2016-04-01

    In Micro-CT (Computed Tomography) system, a series of projection data of sample are collected by the detector as the precision stage rotates step by step. However, the accuracy of projection images is limited by rotation errors during the acquisition process. Therefore, evaluating the performance of precision rotary stage and developing corresponding compensation method are necessary in Micro-CT system. In this paper, a metered system is designed which is composed of four precision capacitive sensors, a precision machined steel cylinder and four flexible hinges. Based on the metered system, a method to calibrate and correct the errors when the precision stage turns is proposed. Firstly, the theoretical analysis is proposed and the imperfect situations are considered. And then, the method has been applied to correct experimental data taken from a microscope type of Micro-CT system. Successful results are shown through evaluating MTF (Modulation Transfer Function) of Micro-CT system. Lastly, a sample of tungsten wire is scanned and the reconstructed images are compared before and after using the calibrated method.

  10. Rotative polarization system of millimetric wave for detecting fiber orientation in CFRP

    SciTech Connect

    Urabe, K. )

    1992-02-01

    A new system for nondestructive and contact-free detection of fiber orientation in fiber reinforced composites such as CFRP was devised using 35 GHz millimetric wave. In this system, by rotating the polarization of the wave and compensating it after passing through the sample, changes of anisotropy caused by changes in fiber orientation of unidirectional CFRP or carbon fiber prepreg can be easily and efficiently checked. Scanning detection of fiber direction and of fiber misorientation are also possible with high sensitivity. Results of measurements with successful sensitivity are shown for several kinds of unidirectional samples with artificial fiber misorientations. 5 refs.

  11. Rotational multispectral fluorescence lifetime imaging and intravascular ultrasound: bimodal system for intravascular applications

    PubMed Central

    Ma, Dinglong; Bec, Julien; Yankelevich, Diego R.; Gorpas, Dimitris; Fatakdawala, Hussain; Marcu, Laura

    2014-01-01

    Abstract. We report the development and validation of a hybrid intravascular diagnostic system combining multispectral fluorescence lifetime imaging (FLIm) and intravascular ultrasound (IVUS) for cardiovascular imaging applications. A prototype FLIm system based on fluorescence pulse sampling technique providing information on artery biochemical composition was integrated with a commercial IVUS system providing information on artery morphology. A customized 3-Fr bimodal catheter combining a rotational side-view fiberoptic and a 40-MHz IVUS transducer was constructed for sequential helical scanning (rotation and pullback) of tubular structures. Validation of this bimodal approach was conducted in pig heart coronary arteries. Spatial resolution, fluorescence detection efficiency, pulse broadening effect, and lifetime measurement variability of the FLIm system were systematically evaluated. Current results show that this system is capable of temporarily resolving the fluorescence emission simultaneously in multiple spectral channels in a single pullback sequence. Accurate measurements of fluorescence decay characteristics from arterial segments can be obtained rapidly (e.g., 20 mm in 5 s), and accurate co-registration of fluorescence and ultrasound features can be achieved. The current finding demonstrates the compatibility of FLIm instrumentation with in vivo clinical investigations and its potential to complement conventional IVUS during catheterization procedures. PMID:24898604

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

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Abhayapala, Thushara D.; Jayalath, Dhammika; Smith, David; Athaudage, Chandra

    2009-12-01

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

  13. Intelligent Robotic Systems Study (IRSS), phase 3

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This phase of the Intelligent Robotic Systems Study (IRSS) examines some basic dynamics and control issues for a space manipulator attached to its worksite through a compliant base. One example of this scenario is depicted, which is a simplified, planar representation of the Flight Telerobotic Servicer (FTS) Development Test Flight 2 (DTF-2) experiment. The system consists of 4 major components: (1) dual FTS arms to perform dextrous tasks; (2) the main body to house power and electronics; (3) an Attachment Stabilization and Positioning Subsystem (ASPS) to provide coarse positioning and stabilization of the arms, and (4) the Worksite Attachment Mechanism (WAM) which anchors the system to its worksite, such as a Space Station truss node or Shuttle bay platform. The analysis is limited to the DTF-2 scenario. The goal is to understand the basic interaction dynamics between the arm, the positioner and/or stabilizer, and the worksite. The dynamics and controls simulation model are described. Analysis and simulation results are presented.

  14. Rotational Quenching Study in Isovalent H+ + CO and H+ + CS Systems

    NASA Astrophysics Data System (ADS)

    Kaur, Rajwant; Dhilip Kumar, T. J.

    2016-06-01

    Cooling and trapping of polar molecules has attracted attention at cold and ultracold temperatures. Extended study of molecular inelastic collision processes of polar interstellar species with proton finds an important astrophysical application to model interstellar medium. Present study includes computation of rate coefficient for molecular rotational quenching process in proton collision with isovalent CO and CS molecules using quantum dynamical close-coupling calculations. Full dimensional ab initio potential energy surfaces have been computed for the ground state for both the systems using internally contracted multireference configuration interaction method and basis sets. Quantum scattering calculations for rotational quenching of isovalent species are studied in the rigid-rotor approximation with CX (X=O, S) bond length fixed at an experimental equilibrium value of 2.138 and 2.900 a.u., respectively. Asymptotic potentials are computed using the dipole and quadrupole moments, and the dipole polarizability components. The resulting long-range potentials with the short-range ab initio interaction potentials have been fitted to study the anisotropy of the rigid-rotor surface using the multipolar expansion coefficients. Rotational quenching cross-section and corresponding rates from j=4 level of CX to lower j' levels have been obtained and found to obey Wigner's threshold law at ultra cold temperatures.

  15. Probing vacuum-induced coherence via magneto-optical rotation in molecular systems

    NASA Astrophysics Data System (ADS)

    Kumar, Pardeep; Deb, Bimalendu; Dasgupta, Shubhrangshu

    2016-05-01

    Vacuum-induced coherence (VIC) arises due to the quantum interference between the spontaneous emission pathways from the degenerate excited states to a common ground state. The stringent requirement for the VIC to occur is the nonorthogonality of the transition dipole matrix elements. Unlike atoms, molecules are the promising systems for exploration of VIC, as it is possible to identify the non-orthogonal transitions due to the coupling of the rotation of molecular axis with molecular electronic angular momentum. Usually, the possible signatures of VIC are obtained by manipulating the absorption of the probe field. In this paper, we show how the dispersion of the probe field can be manipulated to obtain a measurable signature of VIC. Precisely speaking, we explore a way to probe VIC in molecules by observing its influence on magneto-optical rotation (MOR). We show that VIC in the presence of a control laser and a magnetic field can lead to large enhancement in the rotation of the plane of polarization of a linearly polarized weak laser with vanishing circular dichroism. This effect can be realized in cold molecular gases. Such a large MOR angle may be used as a tool for optical magnetometry to detect weak magnetic field with large measurement sensitivity.

  16. Study of photometric phase curve with new brightness model: refining phase function system parameters of asteroid (107) Camilla

    NASA Astrophysics Data System (ADS)

    Wang, Yi-Bo; Wang, Xiao-Bin; Wang, Ao

    2016-09-01

    We characterize the morphology of the photometric phase curve model of an asteroid with a three-parameter magnitude phase function H — G1 — G2 system by considering the effect of brightness variation arising from a triaxial ellipsoid representing the asteroid's shape. Applying this new model and a Markov Chain Monte Carlo method, we refine the photometric phase curve of asteroid (107) Camilla and obtain its absolute magnitude H = 7.026-0.054+0.052 mag, and phase function parameters G1 = 0.489-0.044+0.043 and G2 = 0.259-0.023+0.023. Meanwhile, we also determine (107) Camilla's orientation of pole (74.1°-4.5°+4.3°, 50.2°-5.0°+5.4°) with rotational period of 4.843928-0.00001+0.000001 h, and axial ratios a/b = 1.409-0.020+0.020 and b/c = 1.249-0.060+0.063. Furthermore, according to the values of phase function parameters G1 and G2, we infer that asteroid (107) Camilla is an X-type asteroid.

  17. Study of photometric phase curve with new brightness model: refining phase function system parameters of asteroid (107) Camilla

    NASA Astrophysics Data System (ADS)

    Wang, Yi-Bo; Wang, Xiao-Bin; Wang, Ao

    2016-09-01

    We characterize the morphology of the photometric phase curve model of an asteroid with a three-parameter magnitude phase function H — G1 — G2 system by considering the effect of brightness variation arising from a triaxial ellipsoid representing the asteroid's shape. Applying this new model and a Markov Chain Monte Carlo method, we refine the photometric phase curve of asteroid (107) Camilla and obtain its absolute magnitude H = 7.026‑0.054+0.052 mag, and phase function parameters G1 = 0.489‑0.044+0.043 and G2 = 0.259‑0.023+0.023. Meanwhile, we also determine (107) Camilla's orientation of pole (74.1°‑4.5°+4.3°, 50.2°‑5.0°+5.4°) with rotational period of 4.843928‑0.00001+0.000001 h, and axial ratios a/b = 1.409‑0.020+0.020 and b/c = 1.249‑0.060+0.063. Furthermore, according to the values of phase function parameters G1 and G2, we infer that asteroid (107) Camilla is an X-type asteroid.

  18. Comparison of short-range-order in liquid- and rotator-phase states of a simple molecular liquid: A reverse Monte Carlo and molecular dynamics analysis of neutron diffraction data

    SciTech Connect

    Pardo, Luis Carlos; Tamarit, Josep Lluis; Veglio, Nestor; Bermejo, Francisco Javier; Cuello, Gabriel Julio

    2007-10-01

    The short-range order (SRO) correlations in liquid- and rotator-phase states of carbon tetrachloride are revisited here. The correlation of some angular magnitudes is used to evaluate the positional and orientational correlations in the liquid as well as in the rotator phase. The results show significant similitudes in the relative position of the molecules surrounding a central one but striking differences in their relative orientations, which could explain the changes in SRO between the two phases and the puzzling behavior of the local density in the liquid and rotator phases.

  19. Evaluation of a low-dose/slow-rotating SPECT-CT system

    NASA Astrophysics Data System (ADS)

    Hamann, M.; Aldridge, M.; Dickson, J.; Endozo, R.; Lozhkin, K.; Hutton, B. F.

    2008-05-01

    The 4-slice CT that forms part of the GE Infinia Hawkeye-4 SPECT-CT scanner (Hawkeye) is evaluated against the diagnostic 16-slice CT that is incorporated in the GE Discovery ST PET-CT system (DST). The x-ray tube of the slow-rotating Hawkeye system (23 s/rotation) operates at approximately a third of the dose of diagnostic systems as used for conventional diagnostic imaging. Image reconstruction is optimized for low noise. High-contrast spatial resolution significantly falls behind diagnostic figures: the average of MTF50 and MTF10 (resolution where the MTF has fallen to 50% and 10%) is 2.8 ± 0.1 cm-1 for Hawkeye and 5.3 ± 0.1 cm-1 for the DST (standard reconstruction filters). Resolution in the direction of the couch movement (z coordinate) is governed by the fixed Hawkeye slice width of 5 mm. Reconstruction accuracy is found to be increased by reducing the default z increment from 4.4 mm to 2.2 mm. Low-contrast object detectability is superior compared with diagnostic systems operating in the Hawkeye dose range. In the diagnostic dose regime, however, small low-contrast details remain visible in DST that are not detectable with Hawkeye. Although not of diagnostic quality, the low-dose Hawkeye provides appropriate data for SPECT attenuation correction and anatomical localization capability. For more information on this article, see medicalphysicsweb.org

  20. Cubic phases and cubic phase dispersions in a phospholipid-based system.

    PubMed

    Johnsson, Markus; Barauskas, Justas; Tiberg, Fredrik

    2005-02-01

    A cubic liquid crystalline phase forming system based on the phospholipid dioleoylphosphatidylethanolamine (DOPE) which is fortified with small amounts of PEGylated (poly(ethylene) glycol) glycerol monooleate (PEG(660)-GMO) is characterized. The cubic phase formed by the DOPE/PEG(660)-GMO/water system coexists with water in the dilute part of the phase diagram and can be fragmented into colloidal size particles with retained cubic phase structure.

  1. Electromechanical design and construction of a rotating radio-frequency coil system for applications in magnetic resonance.

    PubMed

    Trakic, Adnan; Weber, Ewald; Li, Bing Keong; Wang, Hua; Liu, Feng; Engstrom, Craig; Crozier, Stuart

    2012-04-01

    While recent studies have shown that rotating a single radio-frequency (RF) coil during the acquisition of magnetic resonance (MR) images provides a number of hardware advantages (i.e., requires only one RF channel, avoids coil-coil coupling and facilitates large-scale multinuclear imaging), they did not describe in detail how to build a rotating RF coil system. This paper presents detailed engineering information on the electromechanical design and construction of a MR-compatible RRFC system for human head imaging at 2 T. A custom-made (bladeless) pneumatic Tesla turbine was used to rotate the RF coil at a constant velocity, while an infrared optical encoder measured the selected frequency of rotation. Once the rotating structure was mechanically balanced and the compressed air supply suitably regulated, the maximum frequency of rotation measured ~14.5 Hz with a 2.4% frequency variation over time. MR images of a water phantom and human head were obtained using the rotating RF head coil system.

  2. Electromechanical design and construction of a rotating radio-frequency coil system for applications in magnetic resonance.

    PubMed

    Trakic, Adnan; Weber, Ewald; Li, Bing Keong; Wang, Hua; Liu, Feng; Engstrom, Craig; Crozier, Stuart

    2012-04-01

    While recent studies have shown that rotating a single radio-frequency (RF) coil during the acquisition of magnetic resonance (MR) images provides a number of hardware advantages (i.e., requires only one RF channel, avoids coil-coil coupling and facilitates large-scale multinuclear imaging), they did not describe in detail how to build a rotating RF coil system. This paper presents detailed engineering information on the electromechanical design and construction of a MR-compatible RRFC system for human head imaging at 2 T. A custom-made (bladeless) pneumatic Tesla turbine was used to rotate the RF coil at a constant velocity, while an infrared optical encoder measured the selected frequency of rotation. Once the rotating structure was mechanically balanced and the compressed air supply suitably regulated, the maximum frequency of rotation measured ~14.5 Hz with a 2.4% frequency variation over time. MR images of a water phantom and human head were obtained using the rotating RF head coil system. PMID:22231668

  3. Integrated design of electrical distribution systems: Phase balancing and phase prediction case studies

    NASA Astrophysics Data System (ADS)

    Dilek, Murat

    Distribution system analysis and design has experienced a gradual development over the past three decades. The once loosely assembled and largely ad hoc procedures have been progressing toward being well-organized. The increasing power of computers now allows for managing the large volumes of data and other obstacles inherent to distribution system studies. A variety of sophisticated optimization methods, which were impossible to conduct in the past, have been developed and successfully applied to distribution systems. Among the many procedures that deal with making decisions about the state and better operation of a distribution system, two decision support procedures will be addressed in this study: phase balancing and phase prediction. The former recommends re-phasing of single- and double-phase laterals in a radial distribution system in order to improve circuit loss while also maintaining/improving imbalances at various balance point locations. Phase balancing calculations are based on circuit loss information and current magnitudes that are calculated from a power flow solution. The phase balancing algorithm is designed to handle time-varying loads when evaluating phase moves that will result in improved circuit losses over all load points. Applied to radial distribution systems, the phase prediction algorithm attempts to predict the phases of single- and/or double phase laterals that have no phasing information previously recorded by the electric utility. In such an attempt, it uses available customer data and kW/kVar measurements taken at various locations in the system. It is shown that phase balancing is a special case of phase prediction. Building on the phase balancing and phase prediction design studies, this work introduces the concept of integrated design, an approach for coordinating the effects of various design calculations. Integrated design considers using results of multiple design applications rather than employing a single application for a

  4. Manipulation of a Bose-Einstein condensate by a time-averaged orbiting potential using phase jumps of the rotating field

    SciTech Connect

    Cleary, P. W.; Hijmans, T. W.; Walraven, J. T. M.

    2010-12-15

    We report on the manipulation of the center-of-mass motion ('sloshing') of a Bose-Einstein condensate in a time-averaged orbiting potential (TOP) trap. We start with a condensate at rest in the center of a static trapping potential. When suddenly replacing the static trap with a TOP trap centered about the same position, the condensate starts to slosh with an amplitude much larger than the TOP micromotion. We show, both theoretically and experimentally, that the direction of sloshing is related to the initial phase of the rotating magnetic field of the TOP. We show further that the sloshing can be quenched by applying a carefully timed and sized jump in the phase of the rotating field.

  5. Influence of counter-rotating interaction on quantum phase transition in Dicke-Hubbard lattice: an extended coherent-state approach

    NASA Astrophysics Data System (ADS)

    Lu, Yongchuan; Wang, Chen

    2016-07-01

    We investigate the ground-state behavior of the Dicke-Hubbard model including counter-rotating terms. By generalizing an extended coherent-state approach within mean-field theory, we self-consistently obtain the ground-state energy and delocalized order parameter. Localization-delocalization quantum phase transition of photons is clearly observed by breaking the parity symmetry. Particularly, Mott lobes are fully suppressed, and the delocalized order parameter shows monotonic enhancement by increasing qubit-cavity coupling strength, in sharp contrast to the Dicke-Hubbard model under rotating-wave approximation. Moreover, the corresponding phase boundaries are stabilized by decreasing photon hopping strength, compared to the Rabi-Hubbard model.

  6. Influence of counter-rotating interaction on quantum phase transition in Dicke-Hubbard lattice: an extended coherent-state approach

    NASA Astrophysics Data System (ADS)

    Lu, Yongchuan; Wang, Chen

    2016-10-01

    We investigate the ground-state behavior of the Dicke-Hubbard model including counter-rotating terms. By generalizing an extended coherent-state approach within mean-field theory, we self-consistently obtain the ground-state energy and delocalized order parameter. Localization-delocalization quantum phase transition of photons is clearly observed by breaking the parity symmetry. Particularly, Mott lobes are fully suppressed, and the delocalized order parameter shows monotonic enhancement by increasing qubit-cavity coupling strength, in sharp contrast to the Dicke-Hubbard model under rotating-wave approximation. Moreover, the corresponding phase boundaries are stabilized by decreasing photon hopping strength, compared to the Rabi-Hubbard model.

  7. Slow and fast light in a phase sensitive system

    NASA Astrophysics Data System (ADS)

    Shen, Shuo; Xu, Xiwei; Xiao, Yanhong

    2013-03-01

    Using atomic motion to coherently spread light information stored in atoms provides a novel means to manipulate atom-light interactions. We demonstrate light splitting with moving atoms in a paraffin coated vapor cell, by using phase sensitive degenerate four wave mixing, or self-rotation. This scheme amplifies the beam splitter signal, and in the meantime maintains the phase coherence between the beam splitter channels. Light storage efficiency in the beam-splitting channel can be also enhanced. Such an amplified beam splitter should have applications in optical memory, optical routers and atomic coherence control.

  8. Method and system for controlling a rotational speed of a rotor of a turbogenerator

    SciTech Connect

    Stahlhut, Ronnie Dean; Vuk, Carl Thomas

    2008-12-30

    A system and method controls a rotational speed of a rotor or shaft of a turbogenerator in accordance with a present voltage level on a direct current bus. A lower threshold and a higher threshold are established for a speed of a rotor or shaft of a turbogenerator. A speed sensor determines speed data or a speed signal for the rotor or shaft associated with a turbogenerator. A voltage regulator adjusts a voltage level associated with a direct current bus within a target voltage range if the speed data or speed signal indicates that the speed is above the higher threshold or below the lower threshold.

  9. Berry's Phase of Atoms with Different Sign of the g-FACTOR in a Conical Rotating Magnetic Field Observed by a Time-Domain Atom Interferometer

    NASA Astrophysics Data System (ADS)

    Morinaga, Atsuo; Narui, Hirotaka; Monma, Akinori; Aoki, Takatoshi

    2006-06-01

    Berry's phase of the atom in the state with a positive or negative g factor for partial cycles of a conical rotating magnetic field was determined using a time-domain atom interferometer. The experimental results show that the solid angle for positive g-factor is ϕ(1-cosθ) and that for a negative g-factor is ϕ(1+cosθ) addition to the reversing the sign.

  10. Phase segregation in a system of active dumbbells

    NASA Astrophysics Data System (ADS)

    Gonnella, Giuseppe; Lamura, Antonio; Suma, Antonio

    2014-04-01

    A systems of self-propelled dumbbells interacting by a Weeks-Chandler-Anderson potential is considered. At sufficiently low temperatures the system phase separates into a dense phase and a gas-like phase. The kinetics of the cluster formation and the growth law for the average cluster size are analyzed.

  11. Quantum Liquid Crystal Phases in Strongly Correlated Fermionic Systems

    ERIC Educational Resources Information Center

    Sun, Kai

    2009-01-01

    This thesis is devoted to the investigation of the quantum liquid crystal phases in strongly correlated electronic systems. Such phases are characterized by their partially broken spatial symmetries and are observed in various strongly correlated systems as being summarized in Chapter 1. Although quantum liquid crystal phases often involve…

  12. A wideband optical monitor for a planetary-rotation coating-system

    SciTech Connect

    Campanelli, M.B.; Smith, D.J.

    1998-12-01

    A substrate-specific, through-planet, wideband optical coating monitor is being developed to increase production yield and the understanding of physical vapor deposition (PVD) coatings fabricated in the Optical Manufacturing Laboratory at the University of Rochester`s Laboratory for Laser Energetics. In-situ wideband optical monitoring of planetary rotation systems allows direct monitoring of large, expensive substrates with complex layering schemes. The optical monitor discussed here is under development for coating several large (e.g., 80.7 x 41.7 x 9.0 cm) polarizers for the National Ignition Facility. Wideband optical monitoring of the production substrates is used in concert with an array of crystal monitors for process control, film parameter evaluation, and error detection with associated design reoptimization. The geometry of a planetary rotation system, which produces good uniformity across large substrates, makes optical monitoring more difficult. Triggering and timing techniques for data acquisition become key to the process because the optical coating is available only intermittently for monitoring. Failure to properly consider the effects of the system dynamics during data retrieval and processing may result in significant decreases in the spectral data`s reliability. Improved data accuracy allows better determination of film thicknesses, indices, and inhomogeneities and enables in-situ error detection for design reoptimization.

  13. Counter-rotating type axial flow pump unit in turbine mode for micro grid system

    NASA Astrophysics Data System (ADS)

    Kasahara, R.; Takano, G.; Murakami, T.; Kanemoto, T.; Komaki, K.

    2012-11-01

    Traditional type pumped storage system contributes to adjust the electric power unbalance between day and night, in general. This serial research proposes the hybrid power system combined the wind power unit with the pump-turbine unit, to provide the constant output for the grid system, even at the suddenly fluctuating/turbulent wind. In the pumping mode, the pump should operate unsteadily at not only the normal but also the partial discharge. The operation may be unstable in the rising portion of the head characteristics at the lower discharge, and/or bring the cavitation at the low suction head. To simultaneously overcome both weak points, the authors have proposed a superior pump unit that is composed of counter-rotating type impellers and a peculiar motor with double rotational armatures. This paper discusses the operation at the turbine mode of the above unit. It is concluded with the numerical simulations that this type unit can be also operated acceptably at the turbine mode, because the unit works so as to coincide the angular momentum change through the front runners/impellers with that thorough the rear runners/impellers, namely to take the axial flow at not only the inlet but also the outlet without the guide vanes.

  14. Conceptual design study for a teleoperator visual system, phase 1

    NASA Technical Reports Server (NTRS)

    Adams, D.; Grant, C.; Johnson, C.; Meirick, R.; Polhemus, C.; Ray, A.; Rittenhouse, D.; Skidmore, R.

    1972-01-01

    Results are reported for work performed during the first phase of the conceptual design study for a teleoperator visual system. This phase consists of four tasks: General requirements, concept development, subsystem requirements and analysis, and concept evaluation.

  15. Phase coexistence and line tension in ternary lipid systems.

    PubMed

    Idema, T; van Leeuwen, J M J; Storm, C

    2009-10-01

    The ternary system consisting of cholesterol, a saturated lipid, and an unsaturated one exhibits a rich phase behavior with multiple phase coexistence regimes. Remarkably, phase separation even occurs when each of the three binary systems consisting of two of these components is a uniform mixture. We use a Flory-Huggins like model in which the phase separation of the ternary system is a consequence of an interaction between all three components to describe the system. From the associated Gibbs free energy we calculate phase diagrams, spinodals, and critical points. Moreover, we use a Van der Waals/Cahn-Hilliard like construction to derive an expression for the line tension between coexisting phases. We show how the line tension depends on the position in the phase diagram, and give an explicit expression for the concentration profile at the phase boundary. PMID:19905359

  16. Greenhouse gas emissions and global warming potential of traditional and diversified tropical rice rotation systems.

    PubMed

    Weller, Sebastian; Janz, Baldur; Jörg, Lena; Kraus, David; Racela, Heathcliff S U; Wassmann, Reiner; Butterbach-Bahl, Klaus; Kiese, Ralf

    2016-01-01

    Global rice agriculture will be increasingly challenged by water scarcity, while at the same time changes in demand (e.g. changes in diets or increasing demand for biofuels) will feed back on agricultural practices. These factors are changing traditional cropping patterns from double-rice cropping to the introduction of upland crops in the dry season. For a comprehensive assessment of greenhouse gas (GHG) balances, we measured methane (CH4 )/nitrous oxide (N2 O) emissions and agronomic parameters over 2.5 years in double-rice cropping (R-R) and paddy rice rotations diversified with either maize (R-M) or aerobic rice (R-A) in upland cultivation. Introduction of upland crops in the dry season reduced irrigation water use and CH4 emissions by 66-81% and 95-99%, respectively. Moreover, for practices including upland crops, CH4 emissions in the subsequent wet season with paddy rice were reduced by 54-60%. Although annual N2 O emissions increased two- to threefold in the diversified systems, the strong reduction in CH4 led to a significantly lower (P < 0.05) annual GWP (CH4  + N2 O) as compared to the traditional double-rice cropping system. Measurements of soil organic carbon (SOC) contents before and 3 years after the introduction of upland crop rotations indicated a SOC loss for the R-M system, while for the other systems SOC stocks were unaffected. This trend for R-M systems needs to be followed as it has significant consequences not only for the GWP balance but also with regard to soil fertility. Economic assessment showed a similar gross profit span for R-M and R-R, while gross profits for R-A were reduced as a consequence of lower productivity. Nevertheless, regarding a future increase in water scarcity, it can be expected that mixed lowland-upland systems will expand in SE Asia as water requirements were cut by more than half in both rotation systems with upland crops. PMID:26386203

  17. Greenhouse gas emissions and global warming potential of traditional and diversified tropical rice rotation systems.

    PubMed

    Weller, Sebastian; Janz, Baldur; Jörg, Lena; Kraus, David; Racela, Heathcliff S U; Wassmann, Reiner; Butterbach-Bahl, Klaus; Kiese, Ralf

    2016-01-01

    Global rice agriculture will be increasingly challenged by water scarcity, while at the same time changes in demand (e.g. changes in diets or increasing demand for biofuels) will feed back on agricultural practices. These factors are changing traditional cropping patterns from double-rice cropping to the introduction of upland crops in the dry season. For a comprehensive assessment of greenhouse gas (GHG) balances, we measured methane (CH4 )/nitrous oxide (N2 O) emissions and agronomic parameters over 2.5 years in double-rice cropping (R-R) and paddy rice rotations diversified with either maize (R-M) or aerobic rice (R-A) in upland cultivation. Introduction of upland crops in the dry season reduced irrigation water use and CH4 emissions by 66-81% and 95-99%, respectively. Moreover, for practices including upland crops, CH4 emissions in the subsequent wet season with paddy rice were reduced by 54-60%. Although annual N2 O emissions increased two- to threefold in the diversified systems, the strong reduction in CH4 led to a significantly lower (P < 0.05) annual GWP (CH4  + N2 O) as compared to the traditional double-rice cropping system. Measurements of soil organic carbon (SOC) contents before and 3 years after the introduction of upland crop rotations indicated a SOC loss for the R-M system, while for the other systems SOC stocks were unaffected. This trend for R-M systems needs to be followed as it has significant consequences not only for the GWP balance but also with regard to soil fertility. Economic assessment showed a similar gross profit span for R-M and R-R, while gross profits for R-A were reduced as a consequence of lower productivity. Nevertheless, regarding a future increase in water scarcity, it can be expected that mixed lowland-upland systems will expand in SE Asia as water requirements were cut by more than half in both rotation systems with upland crops.

  18. Coherent optical monolithic phased-array antenna steering system

    DOEpatents

    Hietala, Vincent M.; Kravitz, Stanley H.; Vawter, Gregory A.

    1994-01-01

    An optical-based RF beam steering system for phased-array antennas comprising a photonic integrated circuit (PIC). The system is based on optical heterodyning employed to produce microwave phase shifting by a monolithic PIC constructed entirely of passive components. Microwave power and control signal distribution to the antenna is accomplished by optical fiber, permitting physical separation of the PIC and its control functions from the antenna. The system reduces size, weight, complexity, and cost of phased-array antenna systems.

  19. A high-speed target-rotation system (taro) for the study of short-lived nuclei

    NASA Astrophysics Data System (ADS)

    Miyatake, H.; Hama, H.; Kamiya, T.; Yoshii, M.; Shinozuka, T.; Fujioka, M.

    1986-05-01

    We describe the design and performance of a high-speed target-rotation system for the study of nuclei far from stability, by which targets can be transported to the detector position in 60 ms after irradiation (90° rotation). The rotor movement and the cyclotron beam pulsing, as well as the data acquisition, are controlled by a microcomputer. Using this device 54Co (T {1}/{2} = 193 ms) and 58Cu (T {1}/{2} = 3.2 s) were observed in a test experiment with a transport efficiency of 71 and 98%, respectively (180° rotation).

  20. Phase transitions in fluids and biological systems

    NASA Astrophysics Data System (ADS)

    Sipos, Maksim

    metric to 16S rRNA metagenomic studies of 6 vertebrate gastrointestinal microbiomes and find that they assembled through a highly non-neutral process. I then consider a phase transition that may occur in nutrient-poor environments such as ocean surface waters. In these systems, I find that the experimentally observed genome streamlining, specialization and opportunism may well be generic statistical phenomena.

  1. Efficient methodologies for system matrix modelling in iterative image reconstruction for rotating high-resolution PET

    NASA Astrophysics Data System (ADS)

    Ortuño, J. E.; Kontaxakis, G.; Rubio, J. L.; Guerra, P.; Santos, A.

    2010-04-01

    A fully 3D iterative image reconstruction algorithm has been developed for high-resolution PET cameras composed of pixelated scintillator crystal arrays and rotating planar detectors, based on the ordered subsets approach. The associated system matrix is precalculated with Monte Carlo methods that incorporate physical effects not included in analytical models, such as positron range effects and interaction of the incident gammas with the scintillator material. Custom Monte Carlo methodologies have been developed and optimized for modelling of system matrices for fast iterative image reconstruction adapted to specific scanner geometries, without redundant calculations. According to the methodology proposed here, only one-eighth of the voxels within two central transaxial slices need to be modelled in detail. The rest of the system matrix elements can be obtained with the aid of axial symmetries and redundancies, as well as in-plane symmetries within transaxial slices. Sparse matrix techniques for the non-zero system matrix elements are employed, allowing for fast execution of the image reconstruction process. This 3D image reconstruction scheme has been compared in terms of image quality to a 2D fast implementation of the OSEM algorithm combined with Fourier rebinning approaches. This work confirms the superiority of fully 3D OSEM in terms of spatial resolution, contrast recovery and noise reduction as compared to conventional 2D approaches based on rebinning schemes. At the same time it demonstrates that fully 3D methodologies can be efficiently applied to the image reconstruction problem for high-resolution rotational PET cameras by applying accurate pre-calculated system models and taking advantage of the system's symmetries.

  2. Phase correction system for automatic focusing of synthetic aperture radar

    DOEpatents

    Eichel, Paul H.; Ghiglia, Dennis C.; Jakowatz, Jr., Charles V.

    1990-01-01

    A phase gradient autofocus system for use in synthetic aperture imaging accurately compensates for arbitrary phase errors in each imaged frame by locating highlighted areas and determining the phase disturbance or image spread associated with each of these highlight areas. An estimate of the image spread for each highlighted area in a line in the case of one dimensional processing or in a sector, in the case of two-dimensional processing, is determined. The phase error is determined using phase gradient processing. The phase error is then removed from the uncorrected image and the process is iteratively performed to substantially eliminate phase errors which can degrade the image.

  3. Solar Power Satellite antenna phase control system hardware simulation, phase 4. Volume 2: Analytical simulation of SPS system performance

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.

    1981-01-01

    The pilot signal parameter optimization and power transponder analyses are presented. The SPS antenna phase control system is modeled and the hardware simulation study described. Ionospheric and system phase error effects and the effects of high power amplifier phase and amplitude jitters are considered. Parameter optimization of the spread spectrum receiver, consisting of the carrier tracking loop and the code tracking loop, is described.

  4. Adjustable Nonlinear Mechanism System for Wideband Energy Harvesting in Rotational Circumstances

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Nakano, K.; Zheng, R.; Cartmell, M. P.

    2016-09-01

    Nonlinear energy harvesters have already been exhibited to draw energy from ambient vibration owing to their particular dynamic characteristics, and are feasible to desirable responses for broadband excitations of bistable and monostable systems. This study proposes an energy harvester for rotational applications, in which a cantilever beam pasted piezoelectric film and magnets with the same polarity are comprised as a nonlinear vibrating system. As the rotationally angular velocity gradually increases, the tensile stress to the cantilever beam is also self-adjusted with the increscent centrifugal force, causing the potential barriers of bistable type become shallow, so that the cantilever beam has the ability to maintain the high energy orbit motion from bistable hardening type to monostable hardening behavior. From the implemented results, the valid bandwidth of angular frequency can be improved from 26 rad/s - 132 rad/s to 15 rad/s - 215 rad/s, under the case of the effect of centrifugal force on nonlinear vibrating behavior. It demonstrates that the centrifugal force can significantly promote the performance of nonlinear energy harvesters.

  5. Impact of Wheat/Faba Bean Mixed Cropping or Rotation Systems on Soil Microbial Functionalities

    PubMed Central

    Wahbi, Sanâa; Prin, Yves; Thioulouse, Jean; Sanguin, Hervé; Baudoin, Ezékiel; Maghraoui, Tasnime; Oufdou, Khalid; Le Roux, Christine; Galiana, Antoine; Hafidi, Mohamed; Duponnois, Robin

    2016-01-01

    Cropping systems based on carefully designed species mixtures reveal many potential advantages in terms of enhancing crop productivity, reducing pest and diseases, and enhancing ecological services. Associating cereals and legume production either through intercropping or rotations might be a relevant strategy of producing both type of culture, while benefiting from combined nitrogen fixed by the legume through its symbiotic association with nitrogen-fixing bacteria, and from a better use of P and water through mycorrhizal associations. These practices also participate to the diversification of agricultural productions, enabling to secure the regularity of income returns across the seasonal and climatic uncertainties. In this context, we designed a field experiment aiming to estimate the 2 years impact of these practices on wheat yield and on soil microbial activities as estimated through Substrate Induced Respiration method and mycorrhizal soil infectivity (MSI) measurement. It is expected that understanding soil microbial functionalities in response to these agricultural practices might allows to target the best type of combination, in regard to crop productivity. We found that the tested cropping systems largely impacted soil microbial functionalities and MSI. Intercropping gave better results in terms of crop productivity than the rotation practice after two cropping seasons. Benefits resulting from intercrop should be highly linked with changes recorded on soil microbial functionalities. PMID:27695462

  6. Characterization of a rotating slat collimator system dedicated to small animal imaging

    NASA Astrophysics Data System (ADS)

    Boisson, F.; Bekaert, V.; El Bitar, Z.; Wurtz, J.; Steibel, J.; Brasse, D.

    2011-03-01

    Some current investigations based on small animal models are dedicated to functional cerebral imaging. They represent a fundamental tool to understand the mechanisms involved in neurodegenerative diseases. In the radiopharmaceutical development approach, the main challenge is to measure the radioactivity distribution in the brain of a subject with good temporal and spatial resolutions. Classical SPECT systems mainly use parallel hole or pinhole collimators. In this paper we investigate the use of a rotating slat collimator system for small animal brain imaging. The proposed prototype consists of a 64-channel multi-anode photomultiplier tube (H8804, Hamamatsu Corp.) coupled to a YAP:Ce crystal highly segmented into 32 strips of 0.575 × 18.4 × 10 mm3. The parameters of the rotating slat collimator are optimized using GATE Monte Carlo simulations. The performance of the proposed prototype in terms of spatial resolution, detection efficiency and signal-to-noise ratio is compared to that obtained with a gamma camera equipped with a parallel hole collimator. Preliminary experimental results demonstrate that a spatial resolution of 1.54 mm can be achieved with a detection efficiency of 0.012% for a source located at 20 mm, corresponding to the position of the brain in the prototype field of view.

  7. Impact of Wheat/Faba Bean Mixed Cropping or Rotation Systems on Soil Microbial Functionalities

    PubMed Central

    Wahbi, Sanâa; Prin, Yves; Thioulouse, Jean; Sanguin, Hervé; Baudoin, Ezékiel; Maghraoui, Tasnime; Oufdou, Khalid; Le Roux, Christine; Galiana, Antoine; Hafidi, Mohamed; Duponnois, Robin

    2016-01-01

    Cropping systems based on carefully designed species mixtures reveal many potential advantages in terms of enhancing crop productivity, reducing pest and diseases, and enhancing ecological services. Associating cereals and legume production either through intercropping or rotations might be a relevant strategy of producing both type of culture, while benefiting from combined nitrogen fixed by the legume through its symbiotic association with nitrogen-fixing bacteria, and from a better use of P and water through mycorrhizal associations. These practices also participate to the diversification of agricultural productions, enabling to secure the regularity of income returns across the seasonal and climatic uncertainties. In this context, we designed a field experiment aiming to estimate the 2 years impact of these practices on wheat yield and on soil microbial activities as estimated through Substrate Induced Respiration method and mycorrhizal soil infectivity (MSI) measurement. It is expected that understanding soil microbial functionalities in response to these agricultural practices might allows to target the best type of combination, in regard to crop productivity. We found that the tested cropping systems largely impacted soil microbial functionalities and MSI. Intercropping gave better results in terms of crop productivity than the rotation practice after two cropping seasons. Benefits resulting from intercrop should be highly linked with changes recorded on soil microbial functionalities.

  8. [Responses of rice-wheat rotation system in south Jiangsu to organic-inorganic compound fertilizers].

    PubMed

    Tian, Heng-Da; Zhang, Li; Zhang, Jian-Chao; Wang, Qiu-Jun; Xu, Da-Bing; Yibati, Halihashi; Xu, Jia-Le; Huang, Qi-Wei

    2011-11-01

    In 2006-2007, a field trial was conducted to study the effects of applying three kinds of organic-inorganic compound fertilizers [rapeseed cake compost plus inorganic fertilizers (RCC), pig manure compost plus inorganic fertilizers (PMC), and Chinese medicine residues plus inorganic fertilizers (CMC)] on the crop growth and nitrogen (N) use efficiency of rice-wheat rotation system in South Jiangsu. Grain yield of wheat and rice in the different fertilization treatments was significantly higher than the control (no fertilization). In treatments RCC, PMC and CMC, the wheat yield was 13.1%, 32.2% and 39.3% lower than that of the NPK compound fertilizer (CF, 6760 kg x hm(-2)), respectively, but the rice yield (8504-9449 kg x hm(-2)) was significantly higher than that (7919 kg x hm(-2)) of CF, with an increment of 7.4%-19.3%. In wheat season, the aboveground dry mass, N accumulation, and N use efficiency in treatments RCC, PMC, and CMC were lower than those of CF, but in rice season, these parameters were significantly higher than or as the same as CF. In sum, all the test three compound fertilizers had positive effects on the rice yield and its nitrogen use efficiency in the rice-wheat rotation system, being most significant for RCC.

  9. Interpretation of Mössbauer experiment in a rotating system: A new proof for general relativity

    NASA Astrophysics Data System (ADS)

    Corda, Christian

    2015-04-01

    A historical experiment by Kündig on the transverse Doppler shift in a rotating system measured with the Mössbauer effect (Mössbauer rotor experiment) has been recently first re-analyzed and then replied by an experimental research group. The results of re-analyzing the experiment have shown that a correct re-processing of Kündig's experimental data gives an interesting deviation of a relative redshift between emission and absorption resonant lines from the standard prediction based on the relativistic dilatation of time. That prediction gives a redshift ∇E/E ≃ -1/2 v2/c2 where v is the tangential velocity of the absorber of resonant radiation, c is the velocity of light in vacuum and the result is given to the accuracy of first-order in v2/c2. Data re-processing gave ∇E/E ≃ - kv2/c2 with k = 0.596 ± 0.006. Subsequent new experimental results by the reply of Kündig experiment have shown a redshift with k = 0.68 ± 0.03 instead. By using Einstein Equivalence Principle, which states the equivalence between the gravitational "force" and the pseudo-force experienced by an observer in a non-inertial frame of reference (included a rotating frame of reference) here we re-analyze the theoretical framework of Mössbauer rotor experiments directly in the rotating frame of reference by using a general relativistic treatment. It will be shown that previous analyses missed an important effect of clock synchronization and that the correct general relativistic prevision in the rotating frame gives k ≃ 2/3 in perfect agreement with the new experimental results. Such an effect of clock synchronization has been missed in various papers in the literature with some subsequent claim of invalidity of relativity theory and/or some attempts to explain the experimental results through "exotic" effects. Our general relativistic interpretation shows, instead, that the new experimental results of the Mössbauer rotor experiment are a new, strong and independent, proof of

  10. Phase and amplitude control system for Stanford Linear Accelerator

    SciTech Connect

    Yoo, S.J.

    1983-09-26

    The computer controlled phase and amplitude detection system measures the instantaneous phase and amplitude of a 1 micro-second 2856 MHz rf pulse at a 180 Hz rate. This will be used for phase feedback control, and also for phase and amplitude jitter measurement. The program, which was originally written by John Fox and Keith Jobe, has been modified to improve the function of the system. The software algorithms used in the measurement are described, as is the performance of the prototype phase and amplitude detector system.

  11. System of fermions confined in a harmonic potential and subject to a magnetic field or a rotational motion

    SciTech Connect

    Naiedja, H.; Quentin, P.; Bartel, J.

    2011-05-15

    Making use of the Bloch density matrix technique, we derive exact analytical expressions for the density profile in Fourier space, for the current density and the so-called integrated current for fermionic systems confined by a two-dimensional harmonic oscillator, in the presence of a magnetic field or in a rotating trap of arbitrary strength. We present numerical, illustrative examples with or without magnetic field (with or without rotation).

  12. Density operator formalism for the description of coherence evolution of a homonuclear two-spin system in rotating solids.

    PubMed

    Zhou, J; Ye, C

    1994-09-01

    Based on a simple disentangling technique of the propagator, a density operator formalism is developed to describe the behavior of a homonuclear two-spin system in rotating solids. It is shown that the coherence evolutions can be characterized in terms of quaternions or a rotation matrix in a three-dimensional space; the coherence transfers between two different spins can thus be analysed well.

  13. Phase-field modelling of a miscible system in spinning droplet tensiometer.

    PubMed

    Vorobev, Anatoliy; Boghi, Andrea

    2016-11-15

    The spinning drop tensiometry is used for measurements of surface tension coefficients, especially, when interfaces are characterised by low and ultra-low interfacial stresses. A droplet of lighter liquid is introduced into a rotating capillary that was initially saturated with another heavier liquid. The tube is subject to axial rotation that results in droplet's elongation along the tube's axis. The equilibrium shape of the droplet is used to determine the surface tension coefficient. In this work, the evolution of a slowly miscible droplet introduced into a spinning capillary is investigated. This technique is frequently employed for studies of the dynamics of miscible systems, even despite the fact that a strict equilibrium is never achieved in a mixture of fully miscible liquids. The numerical modelling of a miscible droplet is fulfilled on the basis of the phase-field (Cahn-Hilliard) approach. The numerical results are compared against the experimental data pursuing two objectives: (i) to verify the use of the phase-field approach as a consistent physics-based approach capable of accurate tracking of the short- and long-term evolution of miscible systems, and (ii) to estimate the values of the phenomenological parameters introduced within the phase-field approach, so making this approach a practical tool for modelling of thermohydrodynamic changes in miscible systems within various configurations. PMID:27501043

  14. Phase-field modelling of a miscible system in spinning droplet tensiometer.

    PubMed

    Vorobev, Anatoliy; Boghi, Andrea

    2016-11-15

    The spinning drop tensiometry is used for measurements of surface tension coefficients, especially, when interfaces are characterised by low and ultra-low interfacial stresses. A droplet of lighter liquid is introduced into a rotating capillary that was initially saturated with another heavier liquid. The tube is subject to axial rotation that results in droplet's elongation along the tube's axis. The equilibrium shape of the droplet is used to determine the surface tension coefficient. In this work, the evolution of a slowly miscible droplet introduced into a spinning capillary is investigated. This technique is frequently employed for studies of the dynamics of miscible systems, even despite the fact that a strict equilibrium is never achieved in a mixture of fully miscible liquids. The numerical modelling of a miscible droplet is fulfilled on the basis of the phase-field (Cahn-Hilliard) approach. The numerical results are compared against the experimental data pursuing two objectives: (i) to verify the use of the phase-field approach as a consistent physics-based approach capable of accurate tracking of the short- and long-term evolution of miscible systems, and (ii) to estimate the values of the phenomenological parameters introduced within the phase-field approach, so making this approach a practical tool for modelling of thermohydrodynamic changes in miscible systems within various configurations.

  15. Position and rotation-invariant pattern recognition system by binary rings masks

    NASA Astrophysics Data System (ADS)

    Solorza, S.; Álvarez-Borrego, J.

    2015-06-01

    In this paper, algorithms invariant to position, rotation, noise and non-homogeneous illumination are presented. Here, several manners are studied to generate binary rings mask filters and the corresponding signatures associated to each image. Also, in this work it is shown that digital systems, which are based on the ?-law non-linear correlation, are ?-invariant for ?. The methodologies are tested using greyscale fossil diatoms digital images (real images), and considering the great similarity between those images the results obtained are excellent. The box plot statistical analysis and the computational cost times yield that the Bessel rings masks are the best option when the images contain a homogeneous illumination and the Fourier masks digital system is the right selection when the non-homogeneous illumination and noise is presented in the images.

  16. MRI-compatible transurethral ultrasound system for the treatment of localized prostate cancer using rotational control.

    PubMed

    Chopra, Rajiv; Baker, Nicole; Choy, Vanessa; Boyes, Aaron; Tang, Kee; Bradwell, David; Bronskill, Michael J

    2008-04-01

    Magnetic resonance imaging (MRI)-guided transurethral ultrasound therapy is a potential minimally invasive treatment for localized prostate cancer offering precise targeting of tissue within the gland, short treatment times, and the capability to quantify the spatial heating pattern delivered during therapy. A significant challenge in MRI-guided ultrasound therapy is the design and construction of MRI-compatible equipment capable of operation in a closed-bore MR imager. We describe a prototype system developed for MRI-guided transurethral ultrasound therapy and characterize the performance of the different components including the heating applicator design, rotational motor, and radio frequency electronics. The ultrasound heating applicator described in this study incorporates a planar transducer and is capable of producing high intensity ultrasound energy in a localized region of tissue. Results demonstrated that the heating applicator exhibits excellent MRI-compatibility, enabling precise MR temperature measurements to be acquired as close as 6 mm from the device. Simultaneous imaging and rotational motion was also possible during treatment using a motor based on piezoelectric actuators. Heating experiments performed in both phantoms and in a canine model with the prototype system verified the capability to perform simultaneous MR imaging and therapy delivery with this system. Real-time control over therapy using MR temperature measurements acquired during heating can be implemented to achieve precise patterns of thermal damage within the prostate gland. The technical feasibility of using the system developed in this study for MRI-guided transurethral ultrasound therapy in a closed-bore MR imager has been demonstrated. PMID:18491529

  17. Phased-mission system analysis using Boolean algebraic methods

    NASA Technical Reports Server (NTRS)

    Somani, Arun K.; Trivedi, Kishor S.

    1993-01-01

    Most reliability analysis techniques and tools assume that a system is used for a mission consisting of a single phase. However, multiple phases are natural in many missions. The failure rates of components, system configuration, and success criteria may vary from phase to phase. In addition, the duration of a phase may be deterministic or random. Recently, several researchers have addressed the problem of reliability analysis of such systems using a variety of methods. A new technique for phased-mission system reliability analysis based on Boolean algebraic methods is described. Our technique is computationally efficient and is applicable to a large class of systems for which the failure criterion in each phase can be expressed as a fault tree (or an equivalent representation). Our technique avoids state space explosion that commonly plague Markov chain-based analysis. A phase algebra to account for the effects of variable configurations and success criteria from phase to phase was developed. Our technique yields exact (as opposed to approximate) results. The use of our technique was demonstrated by means of an example and present numerical results to show the effects of mission phases on the system reliability.

  18. Balanced Rotating Spray Tank and Pipe Cleaning and Cleanliness Verification System

    NASA Technical Reports Server (NTRS)

    Caimi, Raoul E. B. (Inventor); Thaxton, Eric A. (Inventor)

    1998-01-01

    A system for cleaning and verifying the cleanliness of the interior surfaces of hollow items, such as small bottles, tanks, pipes and tubes, employs a rotating spray head for supplying a gas-liquid cleaning mixture to the item's surface at a supersonic velocity. The spray head incorporates a plurality of nozzles having diverging cross sections so that the incoming gas-liquid mixture is first converged within the spray head and then diverged through the nozzles, thereby accelerating the mixture to a supersonic velocity. In the preferred embodiment, three nozzles are employed; one forwardly facing nozzle at the end of the spray head and two oppositely facing angled nozzles exiting on opposite sides of the spray head which balance each other, and therefore impart no net side load on the spray head. A drive mechanism is provided to rotate the spray head and at the same time move the head back and forth within the item to be cleaned. The drive mechanism acts on a long metal tube to which the spray head is fixed, and thus no moving parts are exposed to the interior surfaces of the items to be cleaned, thereby reducing the risk of contamination.

  19. Solar Power Satellite antenna phase control system hardware simulation, phase 4: Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.

    1981-01-01

    The phase control system is described. Potential sources of phase error are identified and the performance leading to selection of the allowable phase error for each source is summarized. The pilot transmitter, the effects of ionospheric, the master slave returnable timing system (MSRTS), the SPS receiver, and the high power amplifier for dc to microwave conversion are considered separately. Design parameters of the pilot transmitter and spacetenna transponder are presented.

  20. Comment on "Origin of tilted-phase generation in systems of ellipsoidal molecules with dipolar interactions''

    NASA Astrophysics Data System (ADS)

    Madhusudana, N. V.

    2014-04-01

    In this Comment, I point out that the physical origin of molecular tilt in the smectic phase, found in the Monte Carlo simulations of systems of rodlike molecules with two terminal antiparallel transverse dipole moments by Bose and Saha [Phys. Rev. E 86, 050701(R) (2012), 10.1103/PhysRevE.86.050701], is similar to the one proposed by McMillan. In particular, unlike in smectic-C liquid crystals, in which the molecules are known to have practically free rotations about their long axes, the molecular rotations are found to be partially frozen in the simulations. Further, I suggest that the attractive interaction between correlated splay fluctuations of the antiparallel polarized sublayers which lie close to each other in adjacent molecular layers give rise to the tilting, rather than a reduced attractive interaction between dipoles belonging to the two dipolar sublayers within one molecular layer, as proposed by the authors.

  1. Evaluation of the Self-Nulling Rotating Eddy Current Probe System

    NASA Technical Reports Server (NTRS)

    Hagemaier, Don; Rengel, Kent; Wincheski, Buzz; Namkung, Min

    1999-01-01

    In order to detect multi-site fatigue cracks located under flush-head rivets, automated eddy current equipment is required. To assure a reliable system, the eddy current probe must be centered easily over the installed rivets. To meet these requirements, the NDE Group at NASA LaRC developed the Self-Nulling Rotating Eddy Current Probe System (SNRECPS) which will be referred to as RPS in this document. The system was evaluated at the FAA, NDI Validation Center, in Albuquerque, New Mexico. The system was capable of detecting a 0.032 inch long crack with a 90/95% PoD. Further evaluations were conducted at Boeing in Long Beach, California. These evaluations included fatigue cracks and notches in a range from 0.025 to 0.100 inch long under flush-head aluminum rivets, and titanium or steel flush-head fasteners. The results of these tests are reported herein. Subsequently, the system was loaned to the USAF Structures Laboratory for the purpose of detecting and measuring short cracks under flush-head rivets in a variety of fatigue test specimens. The inspection task was to detect and plot crack growth from numbered fasteners in lettered rows. In January, 1998, the system was taken to Northwest Airlines Maintenance Base, in Atlanta, to inspect a DC-9, for multi-site cracks in three circumferential splices. The aircraft had 83,000 cycles. The inspection was conducted at 30 kHz from longeron 5 left to longeron 5 right. The system was calibrated using a 0,030 EDM first layer notch. The instrument gain was set to 19 mV from the notch. The reject level was set at 10 mV and the unflawed fasteners yielded a signal amplitude of 2 to 3 mV. Only one fastener location, out of about 2,500 tested, yielded a signal of 58 mV. The rivet was removed and visually evaluated. It appeared to be a slight gouge in the counter-sink zone. No fatigue cracks were detected. The same fastener locations were also inspected using the Boeing MAUS system at 60 kHz. No cracks were detected. Thus far, the

  2. Phase-factor-dependent symmetries and quantum phases in a three-level cavity QED system

    NASA Astrophysics Data System (ADS)

    Fan, Jingtao; Yu, Lixian; Chen, Gang; Jia, Suotang

    2016-05-01

    Unlike conventional two-level particles, three-level particles may support some unitary-invariant phase factors when they interact coherently with a single-mode quantized light field. To gain a better understanding of light-matter interaction, it is thus necessary to explore the phase-factor-dependent physics in such a system. In this report, we consider the collective interaction between degenerate V-type three-level particles and a single-mode quantized light field, whose different components are labeled by different phase factors. We mainly establish an important relation between the phase factors and the symmetry or symmetry-broken physics. Specifically, we find that the phase factors affect dramatically the system symmetry. When these symmetries are breaking separately, rich quantum phases emerge. Finally, we propose a possible scheme to experimentally probe the predicted physics of our model. Our work provides a way to explore phase-factor-induced nontrivial physics by introducing additional particle levels.

  3. Interobserver Agreement in the Classification of Partial-Thickness Rotator Cuff Tears Using the Snyder Classification System

    PubMed Central

    Lee, Christopher S.; Davis, Shane M.; Doremus, Brittany; Kouk, Shalen; Stetson, William B.

    2016-01-01

    Background: At present, there is no widely accepted classification system for partial-thickness rotator cuff tears, and as a result, optimal treatment remains controversial. Purpose: To examine the interobserver reliability and accuracy of classifying partial rotator cuff tears using the Snyder classification system. We hypothesized that the Snyder classification would be reproducible with high reliability and accuracy. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Twenty-seven orthopaedic surgeons reviewed 10 video-recorded shoulder arthroscopies. Each surgeon was provided with a description of the Snyder classification system for partial-thickness rotator cuff tears and was then instructed to use this system to describe each tear. Interrater kappa statistics and percentage agreement between observers were calculated to measure the level of agreement. Surgeon experience as well as fellowship training was evaluated to determine possible correlations. Results: A kappa coefficient of 0.512 indicated moderate reliability between surgeons using the Snyder classification to describe partial-thickness rotator cuff tears. The mean correct score was 80%, which indicated “very good” agreement. There was no correlation between the number of shoulder arthroscopies performed per year and fellowship training and the number of correct scores. Conclusion: The Snyder classification system is reproducible and can be used in future research studies in analyzing the treatment options of partial rotator cuff tears. PMID:27738643

  4. Phase-space networks of geometrically frustrated systems.

    PubMed

    Han, Yilong

    2009-11-01

    We illustrate a network approach to the phase-space study by using two geometrical frustration models: antiferromagnet on triangular lattice and square ice. Their highly degenerated ground states are mapped as discrete networks such that the quantitative network analysis can be applied to phase-space studies. The resulting phase spaces share some comon features and establish a class of complex networks with unique Gaussian spectral densities. Although phase-space networks are heterogeneously connected, the systems are still ergodic due to the random Poisson processes. This network approach can be generalized to phase spaces of some other complex systems.

  5. Phase-space networks of geometrically frustrated systems

    NASA Astrophysics Data System (ADS)

    Han, Yilong

    2009-11-01

    We illustrate a network approach to the phase-space study by using two geometrical frustration models: antiferromagnet on triangular lattice and square ice. Their highly degenerated ground states are mapped as discrete networks such that the quantitative network analysis can be applied to phase-space studies. The resulting phase spaces share some comon features and establish a class of complex networks with unique Gaussian spectral densities. Although phase-space networks are heterogeneously connected, the systems are still ergodic due to the random Poisson processes. This network approach can be generalized to phase spaces of some other complex systems.

  6. Integrated thermal treatment system sudy: Phase 2, Results

    SciTech Connect

    Feizollahi, F.; Quapp, W.J.

    1995-08-01

    This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study, the results of which have been published as an interim report, examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 2 systems. The assumptions and methods were the same as for the Phase 1 study. The quantities, and physical and chemical compositions, of the input waste used in he Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr).

  7. Rotational spectroscopy of ClZnCH3 (X1A1): Gas-phase synthesis and characterization of a monomeric Grignard-type reagent

    NASA Astrophysics Data System (ADS)

    Min, J.; Bucchino, M. P.; Kilchenstein, K. M.; Ziurys, L. M.

    2016-02-01

    The pure rotational spectrum of the organozinc halide, ClZnCH3 (X1A1), has been measured using Fourier-transform microwave (FTMW) and millimeter-wave direct-absorption methods in the frequency range 10-296 GHz. This work is the first study of ClZnCH3 by gas-phase spectroscopy. The molecule was created in a DC discharge from the reaction of zinc vapor, produced either by a Broida-type oven or by laser ablation, with chloromethane in what appears to be a metal insertion process. Rotational and chlorine quadrupole constants were determined for three zinc isotopologues. The Znsbnd Cl bond was found to be partly ionic and significantly shorter than in EtZnCl.

  8. Two-Phase Thermal Management Systems for Space

    NASA Astrophysics Data System (ADS)

    Downing, Scott; Andres, Mike; Nguyen, Dam; Halsey, Dave; Bauch, Tim

    2006-01-01

    Active two-phase thermal management systems have been shown to be weight and power effective for space platforms dissipating over 20 kWt of waste heat. A two-phase thermal management system can provide nearly isothermal heat transport at mass flows significantly lower than required for single-phase systems by employing a working fluid's latent heat rather than absorbing the heat sensibly in temperature change. Phase management issues specific to reduced gravity include pump cavitation, loop inventory control and potential dry out in the evaporator. Hamilton Sundstrand has developed and demonstrated in a reduced gravity aircraft environment, a suite of two-phase technologies that manage the liquid-vapor phase distribution. These technologies keep the liquid phase available at the pump inlet for pumping and present at heat acquisition boundaries for evaporation. This paper reviews these technologies for future high power, long duration space platforms.

  9. On the coronae of rapidly rotating stars. I - The relation between rotation and coronal activity in RS CVn systems

    NASA Technical Reports Server (NTRS)

    Walter, F. M.; Bowyer, S.

    1981-01-01

    Soft X-ray observations are presented of a nearly complete sample of RS Canum Venaticorum systems taken with the Einstein X-ray Observatory. It is shown that the quiescent coronal activity, as measured by the ratio of the X-ray to bolometric flux, is directly proportional to the angular velocity of the star with the active chromosphere in these systems. This relation is found to hold over two decades in angular velocity. It is also found that the stellar surface gravity has no obvious influence on the ratio of the X-ray luminosity to the bolometric luminosity over two decades in surface gravity. It is pointed out that the linear relation between the ratio of the X-ray luminosity to the bolometric luminosity on the one hand, and the angular velocity, on the other, holds important implications for dynamo theories of the generation of stellar magnetic fields.

  10. Sub-daily resolution of earth rotation variations with Global Positioning System measurements

    NASA Technical Reports Server (NTRS)

    Lichten, Stephen M.; Marcus, Steven L.; Dickey, Jean O.

    1992-01-01

    Data from a worldwide Global Positioning System (GPS) tracking experiment have been used to determine variations in earth rotation (UT1-UTC) over a time period of three weeks. Kalman filtering and smoothing enabled changes in UT1-UTC over intervals of 2 to 24 hrs to be detected with the GPS data. Internal consistency checks and comparisons with other solutions from very long baseline interferometry (VLBI) and satellite laser ranging (SLR) indicate that the GPS UT1-UTC estimates are accurate to about 2 cm. Comparison of GPS-estimated variations in UT1-UTC with 2-hr time resolution over 4 days with predicted variations computed from diurnal and semidiurnal oceanic tidal contributions strongly suggests that the observed periodic sub-daily variations of about 0.1 msec are largely of tidal origin.

  11. Rotating system for four-dimensional transverse rms-emittance measurements

    NASA Astrophysics Data System (ADS)

    Xiao, C.; Maier, M.; Du, X. N.; Gerhard, P.; Groening, L.; Mickat, S.; Vormann, H.

    2016-07-01

    Knowledge of the transverse four-dimensional beam rms parameters is essential for applications that involve lattice elements that couple the two transverse degrees of freedom (planes). Of special interest is the elimination of interplane correlations to reduce the projected emittances. A dedicated rotating system for emittance measurements (ROSE) has been proposed, developed, and successfully commissioned to fully determine the four-dimensional beam matrix. This device has been used at the high charge injector (HLI) at GSI in a beam line which is composed of a skew quadrupole triplet, a normal quadrupole doublet, and ROSE. Mathematical algorithms, measurements, and the analysis of errors and the decoupling capability for ion beams of 83Kr 13+ at 1.4 MeV /u are reported in this paper.

  12. Two-phase flows within systems with ambient pressure

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Braun, M. J.; Wheeler, R. L., III; Mullen, R. L.

    1985-01-01

    In systems where the design inlet and outlet pressures are maintained above the thermodynamic critical pressure, it is often assumed that two phase flows within the system cannot occur. Designers rely on this simple rule of thumb to circumvent problems associated with a highly compressible two phase flow occurring within the supercritical pressure system along with the uncertainties in rotordynamics, load capacity, heat transfer, fluid mechanics, and thermophysical property variations. The simple rule of thumb is adequate in many low power designs but is inadequate for high performance turbomachines and linear systems, where two phase regions can exist even though outlet pressure is greater than critical pressure. Rotordynamic-fluid-mechanic restoring forces depend on momentum differences, and those for a two phase zone can differ significantly from those for a single-phase zone. Using the Reynolds equation the angular velocity, eccentricity, geometry, and ambient conditions are varied to determine the point of two phase flow incipience.

  13. Phase curves of the Kepler-11 multi-planet system

    SciTech Connect

    Gelino, Dawn M.; Kane, Stephen R.

    2014-06-01

    The Kepler mission has allowed the detection of numerous multi-planet exosystems where the planetary orbits are relatively compact. The first such system detected was Kepler-11 which has six known planets at the present time. These kinds of systems offer unique opportunities to study constraints on planetary albedos by taking advantage of both the precision timing and photometry provided by Kepler data to monitor possible phase variations. Here we present a case study of the Kepler-11 system in which we investigate the phase modulation of the system as the planets orbit the host star. We provide predictions of maximum phase modulation where the planets are simultaneously close to superior conjunction. We use corrected Kepler data for Q1-Q17 to determine the significance of these phase peaks. We find that data quarters where maximum phase peaks occur are better fit by a phase model than a 'null hypothesis' model.

  14. Water monitor system: Phase 1 test report

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Jeffers, E. L.

    1976-01-01

    Automatic water monitor system was tested with the objectives of assuring high-quality effluent standards and accelerating the practice of reclamation and reuse of water. The NASA water monitor system is described. Various components of the system, including the necessary sensors, the sample collection system, and the data acquisition and display system, are discussed. The test facility and the analysis methods are described. Test results are reviewed, and recommendations for water monitor system design improvement are presented.

  15. D Modelling of AN Indoor Space Using a Rotating Stereo Frame Camera System

    NASA Astrophysics Data System (ADS)

    Kang, J.; Lee, I.

    2016-06-01

    Sophisticated indoor design and growing development in urban architecture make indoor spaces more complex. And the indoor spaces are easily connected to public transportations such as subway and train stations. These phenomena allow to transfer outdoor activities to the indoor spaces. Constant development of technology has a significant impact on people knowledge about services such as location awareness services in the indoor spaces. Thus, it is required to develop the low-cost system to create the 3D model of the indoor spaces for services based on the indoor models. In this paper, we thus introduce the rotating stereo frame camera system that has two cameras and generate the indoor 3D model using the system. First, select a test site and acquired images eight times during one day with different positions and heights of the system. Measurements were complemented by object control points obtained from a total station. As the data were obtained from the different positions and heights of the system, it was possible to make various combinations of data and choose several suitable combinations for input data. Next, we generated the 3D model of the test site using commercial software with previously chosen input data. The last part of the processes will be to evaluate the accuracy of the generated indoor model from selected input data. In summary, this paper introduces the low-cost system to acquire indoor spatial data and generate the 3D model using images acquired by the system. Through this experiments, we ensure that the introduced system is suitable for generating indoor spatial information. The proposed low-cost system will be applied to indoor services based on the indoor spatial information.

  16. Rotatable reagent cartridge for high-performance microvalve system on a centrifugal microfluidic device.

    PubMed

    Kawai, Takayuki; Naruishi, Nahoko; Nagai, Hidenori; Tanaka, Yoshihide; Hagihara, Yoshihisa; Yoshida, Yasukazu

    2013-07-16

    Recently, microfluidic lab-on-a-CD (LabCD) has attracted attentions of researchers for its potential for pumpless, compact, and chip-inclusive on-site bioassay. To control the fluids in the LabCD, microvalves such as capillary, hydrophobic, siphon, and sacrificial valves have been employed. However, no microvalve can regulate more than one channel. In a complicated bioassay with many sequential mixing, washing, and wasting steps, thus, an intricate fluidic network with many microchannels, microvalves, and reservoirs is required, which increases assay costs in terms of both system development and chip preparation. To address this issue, we developed a rotatable reagent cartridge (RRC), which was a column-shaped tank and has several rooms to store different reagents. By embedding and rotating the RRC in the LabCD with a simple mechanical force, only the reagent in the room connected to the following channel was injected. By regulating the angle of the RRC to the LabCD, conservation and ejection of each reagent could be switched. Our developed RRC had no air vent hole, which was achieved by the gas-permeable gap between the bottle and cap parts of the RRC. The RRC could inject 230 nL-10 μL of reagents with good recoveries more than 96%. Finally, an enzymatic assay of L-lactate was demonstrated, where the number of valves and reservoirs were well minimized, significantly simplifying the fluidic system and increasing the channel integratability. Well quantitative analyses of 0-100 μM L-lactate could easily be carried out with R(2) > 0.999, indicating the practical utility of the RRC for microfluidic bioanalysis. PMID:23802811

  17. 46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. 108.437 Section 108.437 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide...

  18. 46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. 108.437 Section 108.437 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide...

  19. 46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. 108.437 Section 108.437 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide...

  20. Single phase inverter for a three phase power generation and distribution system

    NASA Technical Reports Server (NTRS)

    Lindena, S. J.

    1976-01-01

    A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

  1. Geometric phase for open quantum systems and stochastic unravelings

    SciTech Connect

    Bassi, Angelo; Ippoliti, Emiliano

    2006-06-15

    We analyze the geometric phase for an open quantum system when computed by resorting to a stochastic unraveling of the reduced density matrix (quantum jump approach or stochastic Schroedinger equations). We show that the resulting phase strongly depends on the type of unraveling used for the calculations: as such, this phase is not a geometric object since it depends on nonphysical parameters, which are not related to the path followed by the density matrix during the evolution of the system.

  2. Investigation of nanoparticle distribution formed by the rotation of the magnetic system

    NASA Astrophysics Data System (ADS)

    Karpov, Andrej; Kozireva, Svetlana; Avotiņa, Dace; Chernobayeva, Lidija; Baryshev, Mikhail

    2014-11-01

    An even dispersion of nanoparticles onto a cell monolayer may open up new options for the gene transfer into cells and this could be a valuable achievement in the field of nanotechnology based drug delivery. Here we report on our evaluation of superparamagnetic iron oxide nanoparticle (SPION) patterning formed by magnetic arrays with unipolar NdFeB magnet arrangements and describe a rotating magnetic array as well as underlying mechanisms of the nanoparticle pattern formation. SPION pattern derived from static magnetic array represents line-like pattern, while the pattern formed by orbital magnetic array is homogenously distributed nanoparticles. Our results show that the SPION sedimentation under the time-phase varying action of magnetic field occurs with horizontal motion of nanoparticles and forms a homogenous distribution of them on the target. In the process, the amplitude of nanoparticle displacement reaches up to 0.5 μm at the magnet boundary, at the greatest linear speed tested of 60 mm/s (magnetic field gradient: 50 T/m). Application of the orbital magnetic array increases the probability of nanoparticle-cell interactions and enhances the efficiency of the gene delivery.

  3. Phases transitions and interfaces in temperature-sensitive colloidal systems

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc; Schall, Peter

    2013-03-01

    Colloids are widely used because of their exceptional properties. Beside their own applications in food, petrol, cosmetics and drug industries, photonic, optical filters and chemical sensor, they are also known as powerful model systems to study molecular phase behavior. Here, we examine both aspects of colloids using temperature-sensitive colloidal systems to fully investigate colloidal phase behavior and colloidal assembly.

  4. Complex rotation in two-dimensional mesh calculations for quantum systems in uniform electric fields

    NASA Astrophysics Data System (ADS)

    Ivanov, Mikhail V.

    2001-06-01

    A computational method for calculations of quasi-steady states of quantum systems is developed on the basis of a complex coordinate transformation and multi-dimensional mesh solution of Schrödinger equations. The two-dimensional implementation of the method is applied to the hydrogen atom, a hydrogen-like system with a screened Coulomb interaction potential and the hydrogen molecular ion H2+ in external electric and parallel electric and magnetic fields. Detailed calculations are carried out for the ground state of the hydrogen atom in parallel electric and magnetic fields. All the systems are considered in cylindrical coordinates (ρ,z). The complex coordinate transformation is applied to the coordinate z, both in the form of a classical complex rotation (atom-like systems) and in the form of a smooth exterior complex scaling. The boundaries of applicability of these methods are studied. In comparison with the boundary-condition method, developed previously, the complex coordinate transformation approach allows one to obtain more precise and stable results for the strong electric field regimes with |ImE|≈|ReE|.

  5. Classification of topological phases in periodically driven interacting systems

    NASA Astrophysics Data System (ADS)

    Else, Dominic V.; Nayak, Chetan

    2016-05-01

    We consider topological phases in periodically driven (Floquet) systems exhibiting many-body localization, protected by a symmetry G . We argue for a general correspondence between such phases and topological phases of undriven systems protected by symmetry Z ⋊G where the additional Z accounts for the discrete time-translation symmetry. Thus, for example, the bosonic phases in d spatial dimensions without intrinsic topological order [symmetry-protected topological (SPT) phases] are classified by the cohomology group Hd +1[Z ⋊G ,U (1 ) ] . For unitary symmetries, we interpret the additional resulting Floquet phases in terms of the lower-dimensional SPT phases that are pumped to the boundary during one time step. These results also imply the existence of novel symmetry-enriched topological (SET) orders protected solely by the periodicity of the drive.

  6. UTILITY ADVANCED TURBINE SYSTEMS (ATS) TECHNOLOGY READINESS TESTING: PHASE 3R

    SciTech Connect

    1999-09-01

    The overall objective of the Advanced Turbine System (ATS) Phase 3 Cooperative Agreement between GE and the US Department of Energy (DOE) is the development of the GE 7H and 9H combined cycle power systems. The major effort will be expended on detail design. Validation of critical components and technologies will be performed, including: hot gas path component testing, sub-scale compressor testing, steam purity test trials, and rotational heat transfer confirmation testing. Processes will be developed to support the manufacture of the first system, which was to have been sited and operated in Phase 4 but will now be sited and operated commercially by GE. This change has resulted from DOE's request to GE for deletion of Phase 4 in favor of a restructured Phase 3 (as Phase 3R) to include full speed, no load (FSNL) testing of the 7H gas turbine. Technology enhancements that are not required for the first machine design but will be critical for future ATS advances in performance, reliability, and costs will be initiated. Long-term tests of materials to confirm design life predictions will continue. A schematic of the GE H machine is shown. This report summarizes work accomplished in 2Q99.

  7. Hopf bifurcation and multistability in a system of phase oscillators.

    PubMed

    Astakhov, Sergey; Fujiwara, Naoya; Gulay, Artem; Tsukamoto, Naofumi; Kurths, Jürgen

    2013-09-01

    We study the phase reduction of two coupled van der Pol oscillators with asymmetric repulsive coupling under an external harmonic force. We show that the system of two phase oscillators undergoes a Hopf bifurcation and possesses multistability on a 2π-periodic phase plane. We describe the bifurcation mechanisms of formation of multistability in the phase-reduced system and show that the Andronov-Hopf bifurcation in the phase-reduced system is not an artifact of the reduction approach but, indeed, has its prototype in the nonreduced system. The bifurcational mechanisms presented in the paper enable one to describe synchronization effects in a wide class of interacting systems with repulsive coupling e.g., genetic oscillators.

  8. ALMA Observations of the Transition from Infall Motion to Keplerian Rotation around the Late-phase Protostar TMC-1A

    NASA Astrophysics Data System (ADS)

    Aso, Yusuke; Ohashi, Nagayoshi; Saigo, Kazuya; Koyamatsu, Shin; Aikawa, Yuri; Hayashi, Masahiko; Machida, Masahiro N.; Saito, Masao; Takakuwa, Shigehisa; Tomida, Kengo; Tomisaka, Kohji; Yen, Hsi-Wei

    2015-10-01

    We have observed the Class I protostar TMC-1A with the Atacama Millimeter/submillimeter Array (ALMA) in the emissions of 12CO and C18O (J = 2–1) and 1.3 mm dust continuum. Continuum emission with a deconvolved size of 0.″50 × 0.″37, perpendicular to the 12CO outflow, is detected. It most likely traces a circumstellar disk around TMC-1A, as previously reported. In contrast, a more extended structure is detected in C18O, although it is still elongated with a deconvolved size of 3.″3 × 2.″2, indicating that C18O traces mainly a flattened envelope surrounding the disk and the central protostar. C18O shows a clear velocity gradient perpendicular to the outflow at higher velocities, indicative of rotation, while an additional velocity gradient along the outflow is found at lower velocities. The radial profile of the rotational velocity is analyzed in detail, finding that it is given as a power law ∝r‑a with an index of ∼0.5 at higher velocities. This indicates that the rotation at higher velocities can be explained as Keplerian rotation orbiting a protostar with a dynamical mass of 0.68 {M}ȯ (inclination corrected). The additional velocity gradient of C18O along the outflow is considered to be mainly infall motions in the envelope. Position–velocity diagrams made from models consisting of an infalling envelope and a Keplerian disk are compared with the observations, revealing that the observed infall velocity is ∼0.3 times smaller than the free-fall velocity yielded by the dynamical mass of the protostar. Magnetic fields could be responsible for the slow infall velocity. A possible scenario of Keplerian disk formation is discussed.

  9. ALMA Observations of the Transition from Infall Motion to Keplerian Rotation around the Late-phase Protostar TMC-1A

    NASA Astrophysics Data System (ADS)

    Aso, Yusuke; Ohashi, Nagayoshi; Saigo, Kazuya; Koyamatsu, Shin; Aikawa, Yuri; Hayashi, Masahiko; Machida, Masahiro N.; Saito, Masao; Takakuwa, Shigehisa; Tomida, Kengo; Tomisaka, Kohji; Yen, Hsi-Wei

    2015-10-01

    We have observed the Class I protostar TMC-1A with the Atacama Millimeter/submillimeter Array (ALMA) in the emissions of 12CO and C18O (J = 2-1) and 1.3 mm dust continuum. Continuum emission with a deconvolved size of 0.″50 × 0.″37, perpendicular to the 12CO outflow, is detected. It most likely traces a circumstellar disk around TMC-1A, as previously reported. In contrast, a more extended structure is detected in C18O, although it is still elongated with a deconvolved size of 3.″3 × 2.″2, indicating that C18O traces mainly a flattened envelope surrounding the disk and the central protostar. C18O shows a clear velocity gradient perpendicular to the outflow at higher velocities, indicative of rotation, while an additional velocity gradient along the outflow is found at lower velocities. The radial profile of the rotational velocity is analyzed in detail, finding that it is given as a power law ∝r-a with an index of ˜0.5 at higher velocities. This indicates that the rotation at higher velocities can be explained as Keplerian rotation orbiting a protostar with a dynamical mass of 0.68 {M}⊙ (inclination corrected). The additional velocity gradient of C18O along the outflow is considered to be mainly infall motions in the envelope. Position-velocity diagrams made from models consisting of an infalling envelope and a Keplerian disk are compared with the observations, revealing that the observed infall velocity is ˜0.3 times smaller than the free-fall velocity yielded by the dynamical mass of the protostar. Magnetic fields could be responsible for the slow infall velocity. A possible scenario of Keplerian disk formation is discussed.

  10. Automated CPX support system preliminary design phase

    NASA Technical Reports Server (NTRS)

    Bordeaux, T. A.; Carson, E. T.; Hepburn, C. D.; Shinnick, F. M.

    1984-01-01

    The development of the Distributed Command and Control System (DCCS) is discussed. The development of an automated C2 system stimulated the development of an automated command post exercise (CPX) support system to provide a more realistic stimulus to DCCS than could be achieved with the existing manual system. An automated CPX system to support corps-level exercise was designed. The effort comprised four tasks: (1) collecting and documenting user requirements; (2) developing a preliminary system design; (3) defining a program plan; and (4) evaluating the suitability of the TRASANA FOURCE computer model.

  11. Stellar yields of rotating first stars

    SciTech Connect

    Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi

    2014-05-02

    First stars, also called population III stars, are born in the earliest universe without any heavy elements. These stars are the first nuclear reactor in the universe and affect their circumstances emitting synthesized materials. Not only the stellar evolution, but also their chemical yields have many distinctive characteristics. We have modeled evolution of population III stars including effect of stellar rotation. Internal mixing induced by rotation naturally results in primary nitrogen production. Evolution of rotating massive stars is followed until the core collapse phase. The new Pop III yield model will consistently explain the observed abundances of metal-poor systems.

  12. Analysis of Petal Rotation Trajectory Characteristics

    NASA Technical Reports Server (NTRS)

    Anderson, Rodney L.; Campagnola, Stefano; Buffington, Brent B.

    2014-01-01

    In this study, the characteristics of petal rotation trajectories are explored in both the two-body and circular restricted three-body problem (CRTBP) models. Petal rotation trajectories alternate long and short resonances of different kinds to rotate the line of apsides. They are typically computed using the patched conic model, and they are used in a number of different missions and mission concepts including Cassini, JUICE, and Europa mission concepts. Petal rotation trajectories are first analyzed here using the patched conic model to quantify their characteristics and search for cases with fast rotation of the line of apsides. When they are computed in the CRTBP, they are unstable periodic orbits with corresponding stable and unstable manifolds. The characteristics of these orbits are explored from a dynamical systems perspective in the second phase of the study.

  13. Phase equilibrium and intermediate phases in the Eu-Sb system

    SciTech Connect

    Abdusalyamova, M.N.

    2011-10-15

    Rapid heating rate thermal analysis, X-ray diffraction, fluorescence spectrometry, and differential dissolution method were used to study the high-temperature phase equilibrium in the Eu-Sb system within the composition range between 37 and 96 at% Sb. The techniques were effective in determination of the vapor-solid-liquid equilibrium since intermediate phases except Eu{sub 4}Sb{sub 3} evaporated incongruently after melting. A thermal procedure was developed to determine the liquidus and solidus lines of the T-x diagram. Six stable phases were identified: two phases, EuSb{sub 2} and Eu{sub 4}Sb{sub 3}, melt congruently at 1045{+-}10 deg. C and 1600{+-}15 deg. C, the Eu{sub 2}Sb{sub 3}, Eu{sub 11}Sb{sub 10}, Eu{sub 5}Sb{sub 4}, and Eu{sub 5}Sb{sub 3} phases melt incongruently at 850{+-}8 deg. C, 950{+-}10 deg. C, 1350{+-}15 deg. C, and 1445{+-}15 deg. C, respectively. The exact composition shifting of Sb-rich decomposable phases towards Eu{sub 4}Sb{sub 3}, the most refractory compound, was determined. The topology of the Eu-Sb phase diagram was considered together with that of the Yb-Sb system. - Graphical abstract: The high-temperature range of the T-x phase diagram for the Eu-Sb system. Highlights: > The phase relations in the Eu-Sb system were studied over a large composition and temperature scale. > The liquidus and solidus lines of the T-x diagram were well established using effective techniques. > In the system, six binary phases are stable and they melt incongruently except EuSb{sub 2} and Eu{sub 4}Sb{sub 3}. > Incongruent evaporation was found to be typical of all the phases besides Eu{sub 4}Sb{sub 3}.

  14. Intermediate phases in some rare earth-ruthenium systems

    NASA Technical Reports Server (NTRS)

    Sharifrazi, P.; Raman, A.; Mohanty, R. C.

    1984-01-01

    The phase equilibria and crystal structures of intermediate phases were investigated in eight representative RE-Ru systems using powder X-ray diffraction and metallographic techniques. The Fe3C, Mn5C2 and Er5Ru3 structures occur in all but the Ce-Ru systems. Phases analogous to Er5Ru3 possess an unknown crystal structure similar to Er5Rh3(I). MgCu2 and MgZn2 type Laves phases are encountered in the light rare earth and heavy rare earth systems, respectively, and RERu2 phases, where RE = Nd and Sm, possess both the Laves phase structures. An intermediate phase, NdRu, with an unknown structure, occurs only in the Nd-Ru system. A bcc structure with 40 atoms per unit cell is encountered in the phases Er3Ru2 and Y3Ru2. The behavior of cerium in Ce-Ru alloys is unique in that four unidentified structures, not encountered in other RE-Ru systems, have been encountered. Also a phase designated as Ce3Ru is found with the Th7Fe3 type structure.

  15. Demonstration Advanced Avionics System (DAAS), Phase 1

    NASA Technical Reports Server (NTRS)

    Bailey, A. J.; Bailey, D. G.; Gaabo, R. J.; Lahn, T. G.; Larson, J. C.; Peterson, E. M.; Schuck, J. W.; Rodgers, D. L.; Wroblewski, K. A.

    1981-01-01

    Demonstration advanced anionics system (DAAS) function description, hardware description, operational evaluation, and failure mode and effects analysis (FMEA) are provided. Projected advanced avionics system (PAAS) description, reliability analysis, cost analysis, maintainability analysis, and modularity analysis are discussed.

  16. Phase error statistics of a phase-locked loop synchronized direct detection optical PPM communication system

    NASA Technical Reports Server (NTRS)

    Natarajan, Suresh; Gardner, C. S.

    1987-01-01

    Receiver timing synchronization of an optical Pulse-Position Modulation (PPM) communication system can be achieved using a phased-locked loop (PLL), provided the photodetector output is suitably processed. The magnitude of the PLL phase error is a good indicator of the timing error at the receiver decoder. The statistics of the phase error are investigated while varying several key system parameters such as PPM order, signal and background strengths, and PPL bandwidth. A practical optical communication system utilizing a laser diode transmitter and an avalanche photodiode in the receiver is described, and the sampled phase error data are presented. A linear regression analysis is applied to the data to obtain estimates of the relational constants involving the phase error variance and incident signal power.

  17. EDUCATIONAL COMMUNICATIONS SYSTEM--PHASE III.

    ERIC Educational Resources Information Center

    WITHERSPOON, JOHN P.; AND OTHERS

    MULTIPURPOSE COMMUNICATIONS SYSTEM MODELS WERE DEVELOPED FOR APPLICATION TO HIGHER EDUCATION. THREE MODEL SYSTEMS - INTRASTATE, INTERSTATE, AND EDUCATIONAL RESOURCES - WERE DESIGNED. THESE SYSTEM DESIGNS WERE ESTABLISHED FOR EASY EVALUATION AND MAXIMUM FLEXIBILITY, WITH A MINIMUM OF PRESET AUTOMATIC EQUIPMENT. TWO ALTERNATIVE TRANSMISSION SYSTEMS…

  18. Origin of Axial Spin and Orbital Rotation of the Solar System

    NASA Astrophysics Data System (ADS)

    Hofmeister, A.; Criss, R. E.

    2011-12-01

    We explain the nearly circular, co-planar orbits and mostly upright axial spins of the planets with a radical, new accretion model. These common and fundamental rotational characteristics record conditions of origin. The Figure below shows that current planetary spin (triangles) and orbital (circles) rotational energies (R.E.) of each planet nearly equal and linearly depend on its gravitational self-potential of formation (Ug). We derive a formula for dissipation of the Sun's spin via photons carrying off angular momentum (radiative braking): for constant luminosity, the primordal Sun (square) lies at the apex of the planetary trends. Total planetary R.E. (grey diamond) lies on the 1:1 line if Jupiter, lost 97% of its spin, like the Earth (open triangle, calculated for a 4 hr primordal day). Hence, the Sun and planets formed contemporaneously and accretion provided little heat. Data on satellite systems provides corroboration. Accretion converted Ug of the 3-dimensional pre-solar nebula to R.E., because (1) the negative sign of Ug forbids conversion exclusively to heat, (2) planetary nebulae are too rarified to produce heat until solid bodies are essentially formed, and (3) configurational energy and PV terms are small compared to Ug. We derive the conversion (-ΔUg~=ΔR.E) from ideal gas behavior, appropriate for low nebula density. From -ΔUg~=ΔR.E, the time-dependent virial theorem, conservation of angular momemtum, and measured masses and other characteristics, we derive a quantitative model which (1) deduces mechanisms, (2) quantifies the time-dependence in converting a 3-d cloud to the present 2-d Solar System, and (3) calculates the evolution of dust and gas densities. Rocky kernels assembled first and rapidly from pre-solar dust in a nebula with nearly uniform density via almost vertical collapse of dust, but not gas, to a disk, verified by stability criteria. Gas giants formed at great distance where rocky kernels out-competes the pull of the central, co

  19. Experimental investigation of thermal processes in the multi-ring Couette system with counter rotation of cylinders

    NASA Astrophysics Data System (ADS)

    Mamonov, V. N.; Nazarov, A. D.; Serov, A. F.; Terekhov, V. I.

    2016-01-01

    The effect of parameters of the multi-ring Couette system with counter rotating coaxial cylinders on the process of thermal energy release in a viscous liquid filling this system is considered with regard to the problem of determining the possibility of creating the high-performance wind heat generator. The multi-cylinder rotor design allows directly conversion of the mechanical power of a device consisting of two "rotor" wind turbines with a common axis normal to the air flow into the thermal energy in a wide range of rotational speed of the cylinders. Experimental results on the measurement of thermal power released in the pilot heat generator at different relative angular speeds of cylinder rotation are presented.

  20. Dual-phase evolution in complex adaptive systems

    PubMed Central

    Paperin, Greg; Green, David G.; Sadedin, Suzanne

    2011-01-01

    Understanding the origins of complexity is a key challenge in many sciences. Although networks are known to underlie most systems, showing how they contribute to well-known phenomena remains an issue. Here, we show that recurrent phase transitions in network connectivity underlie emergent phenomena in many systems. We identify properties that are typical of systems in different connectivity phases, as well as characteristics commonly associated with the phase transitions. We synthesize these common features into a common framework, which we term dual-phase evolution (DPE). Using this framework, we review the literature from several disciplines to show that recurrent connectivity phase transitions underlie the complex properties of many biological, physical and human systems. We argue that the DPE framework helps to explain many complex phenomena, including perpetual novelty, modularity, scale-free networks and criticality. Our review concludes with a discussion of the way DPE relates to other frameworks, in particular, self-organized criticality and the adaptive cycle. PMID:21247947

  1. COHERENT LASER VISION SYSTEM (CLVS) OPTION PHASE

    SciTech Connect

    Robert Clark

    1999-11-18

    The purpose of this research project was to develop a prototype fiber-optic based Coherent Laser Vision System (CLVS) suitable for DOE's EM Robotic program. The system provides three-dimensional (3D) vision for monitoring situations in which it is necessary to update the dimensional spatial data on the order of once per second. The system has total immunity to ambient lighting conditions.

  2. Free vibration analysis of a multiple rotating nano-beams system based on the Eringen nonlocal elasticity theory

    NASA Astrophysics Data System (ADS)

    Ghafarian, M.; Ariaei, A.

    2016-08-01

    The free vibration analysis of a multiple rotating nanobeams' system applying the nonlocal Eringen elasticity theory is presented. Multiple nanobeams' systems are of great importance in nano-optomechanical applications. At nanoscale, the nonlocal effects become non-negligible. According to the nonlocal Euler-Bernoulli beam theory, the governing partial differential equations are derived by incorporating the nonlocal scale effects. Assuming a structure of n parallel nanobeams, the vibration of the system is described by a coupled set of n partial differential equations. The method involves a change of variables to uncouple the equations and the differential transform method as an efficient mathematical technique to solve the nonlocal governing differential equations. Then a number of parametric studies are conducted to assess the effect of the nonlocal scaling parameter, rotational speed, boundary conditions, hub radius, and the stiffness coefficients of the elastic interlayer media on the vibration behavior of the coupled rotating multiple-carbon-nanotube-beam system. It is revealed that the bending vibration of the system is significantly influenced by the rotational speed, elastic mediums, and the nonlocal scaling parameters. This model is validated by comparing the results with those available in the literature. The natural frequencies are in a reasonably good agreement with the reported results.

  3. Effects of gasket on coupled plastic flow and strain-induced phase transformations under high pressure and large torsion in a rotational diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Feng, Biao; Levitas, Valery I.

    2016-01-01

    Combined plastic flow and strain-induced phase transformations (PTs) under high pressure in a sample within a gasket subjected to three dimensional compression and torsion in a rotational diamond anvil cell (RDAC) are studied using a finite element approach. The results are obtained for the weaker, equal-strength, and stronger high-pressure phases in comparison with low-pressure phases. It is found that, due to the strong gasket, the pressure in the sample is relatively homogenous and the geometry of the transformed zones is mostly determined by heterogeneity in plastic flow. For the equal-strength phases, the PT rate is higher than for the weaker and stronger high-pressure phases. For the weaker high-pressure phase, transformation softening induces material instability and leads to strain and PT localization. For the stronger high-pressure phase, the PT is suppressed by strain hardening during PT. The effect of the kinetic parameter k that scales the PT rate in the strain-controlled kinetic equation is also examined. In comparison with a traditional diamond anvil cell without torsion, the PT progress is much faster in RDAC under the same maximum pressure in the sample. Finally, the gasket size and strength effects are discussed. For a shorter and weaker gasket, faster plastic flow in radial and thickness directions leads to faster PT kinetics in comparison with a longer and stronger gasket. The rates of PT and plastic flows are not very sensitive to the modest change in a gasket thickness. Multiple experimental results are reproduced and interpreted. Obtained results allow one to design the desired pressure-plastic strain loading program in the experiments for searching new phases, reducing PT pressure by plastic shear, extracting kinetic properties from experiments with heterogeneous fields, and controlling homogeneity of all fields and kinetics of PTs.

  4. Phase structure of one-dimensional interacting Floquet systems. I. Abelian symmetry-protected topological phases

    NASA Astrophysics Data System (ADS)

    von Keyserlingk, C. W.; Sondhi, S. L.

    2016-06-01

    Recent work suggests that a sharp definition of "phase of matter" can be given for some quantum systems out of equilibrium, first for many-body localized systems with time-independent Hamiltonians and more recently for periodically driven or Floquet localized systems. In this work, we propose a classification of the finite Abelian symmetry-protected phases of interacting Floquet localized systems in one dimension. We find that the different Floquet phases correspond to elements of ClG×AG , where ClG is the undriven interacting classification, and AG is a set of (twisted) one-dimensional representations corresponding to symmetry group G . We will address symmetry-broken phases in a subsequent paper C. W. von Keyserlingk and S. L. Sondhi, following paper, Phys. Rev. B 93, 245146 (2016), 10.1103/PhysRevB.93.245146.

  5. Differential phase contrast X-ray imaging system and components

    SciTech Connect

    Stutman, Daniel; Finkenthal, Michael

    2014-07-01

    A differential phase contrast X-ray imaging system includes an X-ray illumination system, a beam splitter arranged in an optical path of the X-ray illumination system, and a detection system arranged in an optical path to detect X-rays after passing through the beam splitter.

  6. Biaxial order and a rotation of the minor director in the nematic phase of an organo-siloxane tetrapode by the electric field

    NASA Astrophysics Data System (ADS)

    Merkel, K.; Nagaraj, M.; Kocot, A.; Kohlmeier, A.; Mehl, G. H.; Vij, J. K.

    2012-03-01

    Biaxiality in the nematic phase for a liquid crystalline tetrapode made up of organo-siloxanes mesogens is investigated using polarized infrared spectroscopy. An ordering of the minor director for the homeotropically aligned sample is found to depend on the amplitude of the in-plane electric field. On increasing the in-plane electric field, the minor director, lying initially along the rubbing direction, rotates to the direction of the applied field. The scalar order parameters of the second rank tensor are found to depend significantly on the strength of the electric field. A most significant increase is found in the nematic order parameter and in the parameter that characterizes the phase biaxiality.

  7. Sleep and satisfaction in 8- and 12-h forward-rotating shift systems: Industrial employees prefer 12-h shifts.

    PubMed

    Karhula, Kati; Härmä, Mikko; Ropponen, Annina; Hakola, Tarja; Sallinen, Mikael; Puttonen, Sampsa

    2016-01-01

    Twelve-hour shift systems have become more popular in industry. Survey data of shift length, shift rotation speed, self-rated sleep, satisfaction and perceived health were investigated for the associations among 599 predominantly male Finnish industrial employees. The studied forward-rotating shift systems were 12-h fast (12fast, DDNN------, n = 268), 8-h fast (8fast, MMEENN----, n = 161) and 8-h slow (8slow, MMMM-EEEE-NNNN, n = 170). Satisfaction with shift system differed between the groups (p < 0.01) after controlling for age, gender, shift work experience and self-rated stress. In the 12fast, 98% of employees were satisfied with their shift system (75% 8fast, 54% 8slow). Negative effects on sleep and alertness were rare (8%) in the 12fast group (53% 8fast, 66% 8 slow, p < 0.01) and self-reported sleep difficulties were less frequent than in the 8fast and 8slow groups (8%, 27%, 41%, respectively, p < 0.01). The self-reported average sleep duration (12fast 7:50, 8fast 7:24, 8slow 7:15, p < 0.01), and shift-specific sleep before and between morning shifts and after first night shift were longer in the 12fast group. Perceived negative effects of the current shift system on general health (12fast 4%, 8fast 30%, 8slow 41%, p < 0.001) and work-life balance (12fast 8%, 8fast 52%, 8slow 63%, p < 0.001) differed strongly between the groups. In conclusion, the perceived effects of shift work were dependent on both shift length and shift rotation speed: employees in the 12-h rapidly forward-rotating shift system were most satisfied, perceived better work-life balance and slept better than the employees in the 8fast or especially the employees in the 8-h slowly rotating systems.

  8. Sleep and satisfaction in 8- and 12-h forward-rotating shift systems: Industrial employees prefer 12-h shifts.

    PubMed

    Karhula, Kati; Härmä, Mikko; Ropponen, Annina; Hakola, Tarja; Sallinen, Mikael; Puttonen, Sampsa

    2016-01-01

    Twelve-hour shift systems have become more popular in industry. Survey data of shift length, shift rotation speed, self-rated sleep, satisfaction and perceived health were investigated for the associations among 599 predominantly male Finnish industrial employees. The studied forward-rotating shift systems were 12-h fast (12fast, DDNN------, n = 268), 8-h fast (8fast, MMEENN----, n = 161) and 8-h slow (8slow, MMMM-EEEE-NNNN, n = 170). Satisfaction with shift system differed between the groups (p < 0.01) after controlling for age, gender, shift work experience and self-rated stress. In the 12fast, 98% of employees were satisfied with their shift system (75% 8fast, 54% 8slow). Negative effects on sleep and alertness were rare (8%) in the 12fast group (53% 8fast, 66% 8 slow, p < 0.01) and self-reported sleep difficulties were less frequent than in the 8fast and 8slow groups (8%, 27%, 41%, respectively, p < 0.01). The self-reported average sleep duration (12fast 7:50, 8fast 7:24, 8slow 7:15, p < 0.01), and shift-specific sleep before and between morning shifts and after first night shift were longer in the 12fast group. Perceived negative effects of the current shift system on general health (12fast 4%, 8fast 30%, 8slow 41%, p < 0.001) and work-life balance (12fast 8%, 8fast 52%, 8slow 63%, p < 0.001) differed strongly between the groups. In conclusion, the perceived effects of shift work were dependent on both shift length and shift rotation speed: employees in the 12-h rapidly forward-rotating shift system were most satisfied, perceived better work-life balance and slept better than the employees in the 8fast or especially the employees in the 8-h slowly rotating systems. PMID:27077442

  9. Wetting transitions in two-, three-, and four-phase systems.

    PubMed

    Hejazi, Vahid; Nosonovsky, Michael

    2012-01-31

    We discuss wetting of rough surfaces with two-phase (solid-liquid), three-phase (solid-water-air and solid-oil-water), and four-phase (solid-oil-water-air) interfaces mimicking fish scales. We extend the traditional Wenzel and Cassie-Baxter models to these cases. We further present experimental observations of two-, three-, and four-phase systems in the case of metal-matrix composite solid surfaces immersed in water and in contact with oil. Experimental observations show that wetting transitions can occur in underwater oleophobic systems. We also discuss wetting transitions as phase transitions using the phase-field approach and show that a phenomenological gradient coefficient is responsible for wetting transition, energy barriers, and wetting/dewetting asymmetry (hysteresis). PMID:22054126

  10. Adaptive optimisation of a generalised phase contrast beam shaping system

    PubMed Central

    Kenny, F.; Choi, F.S.; Glückstad, J.; Booth, M.J.

    2015-01-01

    The generalised phase contrast (GPC) method provides versatile and efficient light shaping for a range of applications. We have implemented a generalised phase contrast system that used two passes on a single spatial light modulator (SLM). Both the pupil phase distribution and the phase contrast filter were generated by the SLM. This provided extra flexibility and control over the parameters of the system including the phase step magnitude, shape, radius and position of the filter. A feedback method for the on-line optimisation of these properties was also developed. Using feedback from images of the generated light field, it was possible to dynamically adjust the phase filter parameters to provide optimum contrast. PMID:26089573

  11. Wetting transitions in two-, three-, and four-phase systems.

    PubMed

    Hejazi, Vahid; Nosonovsky, Michael

    2012-01-31

    We discuss wetting of rough surfaces with two-phase (solid-liquid), three-phase (solid-water-air and solid-oil-water), and four-phase (solid-oil-water-air) interfaces mimicking fish scales. We extend the traditional Wenzel and Cassie-Baxter models to these cases. We further present experimental observations of two-, three-, and four-phase systems in the case of metal-matrix composite solid surfaces immersed in water and in contact with oil. Experimental observations show that wetting transitions can occur in underwater oleophobic systems. We also discuss wetting transitions as phase transitions using the phase-field approach and show that a phenomenological gradient coefficient is responsible for wetting transition, energy barriers, and wetting/dewetting asymmetry (hysteresis).

  12. Tether deployment monitoring system, phase 2

    NASA Technical Reports Server (NTRS)

    1989-01-01

    An operational Tether Deployment Monitoring System (TEDEMS) was constructed that would show system functionality in a terrestrial environment. The principle function of the TEDEMS system is the launching and attachment of reflective targets onto the tether during its deployment. These targets would be tracked with a radar antenna that was pointed towards the targets by a positioning system. A spring powered launcher for the targets was designed and fabricated. An instrumentation platform and launcher were also developed. These modules are relatively heavy and will influence tether deployment scenarios, unless they are released with a velocity and trajectory closely matching that of the tether. Owing to the tracking range limitations encountered during field trails of the Radar system, final TEDEMS system integration was not completed. The major module not finished was the system control computer. The lack of this device prevented any subsystem testing or field trials to be conducted. Other items only partially complete were the instrumentation platform launcher and modules and the radar target launcher. The work completed and the tests performed suggest that the proposed system continues to be a feasible approach to tether monitoring, although additional effort is still necessary to increase the range at which modules can be detected. The equipment completed and tested, to the extent stated, is available to NASA for use on any future program that requires tether tracking capability.

  13. Tactile stimulations and wheel rotation responses: toward augmented lane departure warning systems

    PubMed Central

    Tandonnet, Christophe; Burle, Borís; Vidal, Franck; Hasbroucq, Thierry

    2014-01-01

    When an on-board system detects a drift of a vehicle to the left or to the right, in what way should the information be delivered to the driver? Car manufacturers have so far neglected relevant results from Experimental Psychology and Cognitive Neuroscience. Here we show that this situation possibly led to the sub-optimal design of a lane departure warning system (AFIL, PSA Peugeot Citroën) implemented in commercially available automobile vehicles. Twenty participants performed a two-choice reaction time task in which they were to respond by clockwise or counter-clockwise wheel-rotations to tactile stimulations of their left or right wrist. They performed poorer when responding counter-clockwise to the right vibration and clockwise to the left vibration (incompatible mapping) than when responding according to the reverse (compatible) mapping. This suggests that AFIL implements the worse (incompatible) mapping for the operators. This effect depended on initial practice with the interface. The present research illustrates how basic approaches in Cognitive Science may benefit to Human Factors Engineering and ultimately improve man-machine interfaces and show how initial learning can affect interference effects. PMID:25324791

  14. Rotation of Bloch sphere induced by Lamb shift in open two-level systems

    NASA Astrophysics Data System (ADS)

    Wang, Guo-You; Tang, Ning; Liu, Ying; Zeng, Hao-Sheng

    2015-05-01

    From a quite general form of the Lindblad-like master equation of open two-level systems (qubits), we study the effect of Lamb shift on the non-Markovian dynamics. We find that the Lamb shift can induce a non-uniform rotation of the Bloch sphere, but that it does not affect the non-Markovianity of the open system dynamics. We determine the optimal initial-state pairs that maximize the backflow of information for the considered master equation and find an interesting phenomenon-the sudden change of the non-Markovianity. We relate the dynamics to the evolution of the Bloch sphere to help us comprehend the obtained results. Project supported by the National Natural Science Foundation of China (Grant Nos. 11275064 and 11075050), the Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20124306110003), the Program for Changjiang Scholars and Innovative Research Team in University, China (Grant No. IRT0964), and the Construct Program of the National Key Discipline, China.

  15. Dynamic binaural sound localization based on variations of interaural time delays and system rotations.

    PubMed

    Baumann, Claude; Rogers, Chris; Massen, Francis

    2015-08-01

    This work develops the mathematical model for a steerable binaural system that determines the instantaneous direction of a sound source in space. The model combines system angular speed and interaural time delays (ITDs) in a differential equation, which allows monitoring the change of source position in the binaural reference frame and therefore resolves the confusion about azimuth and elevation. The work includes the analysis of error propagation and presents results from a real-time application that was performed on a digital signal processing device. Theory and experiments demonstrate that the azimuthal angle to the sound source is accurately yielded in the case of horizontal rotations, whereas the elevation angle is estimated with large uncertainty. This paper also proves the equivalence of the ITD derivative and the Doppler shift appearing between the binaurally captured audio signals. The equation of this Doppler shift is applicable for any kind of motion. It shows that weak binaural pitch differences may represent an additional cue in localization of sound. Finally, the paper develops practical applications from this relationship, such as the synthesizing of binaural images of pure and complex tones emitted by a moving source, and the generation of multiple frequency images for binaural beat experiments. PMID:26328682

  16. Slit-mounted LED fiducial system for rotating mirror streak cameras

    SciTech Connect

    Shaw, L.L.; Muelder, S.A.; Rivera, A.T.

    1991-01-01

    We have developed a fiducial system for rotating mirror streak cameras that utilizes light emitting diodes mounted at the slit position of the camera. The diodes are driven to the required high brightness by a unique pulse power circuit designed to provide high voltage, high current pulses 18 nanoseconds in length at a frequency of up to 2.5 megahertz. The availability of super bright light emitting diodes with a wavelength of 630 to 640 nanometers allows us to record fiducial pulses, at streaking speeds in excess of 20mm per microsecond, on all the black and white films commonly used in high speed photography. The time marks on the film record are referenced to the real time of the experiment from a clock-driver that controls the start and frequency of the fiducial pulse train and by three adjustable and discreet blanked fiducials. This paper discusses the development of this system and describes the full setup as used at LLNL. 6 refs., 4 figs.

  17. Determination of Earth rotation by the combination of data from different space geodetic systems

    NASA Technical Reports Server (NTRS)

    Archinal, Brent Allen

    1987-01-01

    Formerly, Earth Rotation Parameters (ERP), i.e., polar motion and UTI-UTC values, have been determined using data from only one observational system at a time, or by the combination of parameters previously obtained in such determinations. The question arises as to whether a simultaneous solution using data from several sources would provide an improved determination of such parameters. To pursue this reasoning, fifteen days of observations have been simulated using realistic networks of Lunar Laser Ranging (LLR), Satellite Laser Ranging (SLR) to Lageos, and Very Long Baseline Interferometry (VLBI) stations. A comparison has been done of the accuracy and precision of the ERP obtained from: (1) the individual system solutions, (2) the weighted means of those values, (3) all of the data by means of the combination of the normal equations obtained in 1, and (4) a grand solution with all the data. These simulations show that solutions done by the normal equation combination and grand solution methods provide the best or nearly the best ERP for all the periods considered, but that weighted mean solutions provide nearly the same accuracy and precision. VLBI solutions also provide similar accuracies.

  18. Tactile stimulations and wheel rotation responses: toward augmented lane departure warning systems.

    PubMed

    Tandonnet, Christophe; Burle, Borís; Vidal, Franck; Hasbroucq, Thierry

    2014-01-01

    When an on-board system detects a drift of a vehicle to the left or to the right, in what way should the information be delivered to the driver? Car manufacturers have so far neglected relevant results from Experimental Psychology and Cognitive Neuroscience. Here we show that this situation possibly led to the sub-optimal design of a lane departure warning system (AFIL, PSA Peugeot Citroën) implemented in commercially available automobile vehicles. Twenty participants performed a two-choice reaction time task in which they were to respond by clockwise or counter-clockwise wheel-rotations to tactile stimulations of their left or right wrist. They performed poorer when responding counter-clockwise to the right vibration and clockwise to the left vibration (incompatible mapping) than when responding according to the reverse (compatible) mapping. This suggests that AFIL implements the worse (incompatible) mapping for the operators. This effect depended on initial practice with the interface. The present research illustrates how basic approaches in Cognitive Science may benefit to Human Factors Engineering and ultimately improve man-machine interfaces and show how initial learning can affect interference effects.

  19. Relaxation time of molecular rotation about its long axis in the smectic-A phase of ferroelectricand antiferroelectric liquid crystals as observed by picosecond optical Kerr effect

    NASA Astrophysics Data System (ADS)

    Miyachi, Kouichi; Takanishi, Yoichi; Ishikawa, Ken; Takezoe, Hideo; Fukuda, Atsuo

    1997-02-01

    We have studied the molecular rotational motion about its long axis in ferroelectric chiral smectic-C (Sm-C) and antiferroelectric chiral smectic-Ca (Sm-C*>A) liquid crystals and observed a few tens of picosecond relaxation time. Previously reported results using degenerate four-wave mixing with 25-ps pump pulses [Lalanne et al., Phys. Rev. A 44, 6632 (1991)] claimed to show a critical slowing down in the temperature region more than 0.1 °C above the Sm-A-Sm-C phase transition. Our measurements of the optical Kerr effect with 130-fs pump pulses do not show any critical slowing down in the corresponding temperature region above the phase transition from Sm-A to Sm-C or Sm-C*>A. The result may indicate that the laser-induced molecular reorientation with τ~10-11 s scarcely couples with the tilt angle and the polarization. A possibility has been discussed that a slower rotational motion with τ>~10-10 s plays a primary role for the emergence of ferroelectricity and/or antiferroelectricity.

  20. Impact of the Condensed-Phase Environment on the Translation-Rotation Eigenstates and Spectra of a Hydrogen Molecule in Clathrate Hydrates.

    PubMed

    Powers, Anna; Marsalek, Ondrej; Xu, Minzhong; Ulivi, Lorenzo; Colognesi, Daniele; Tuckerman, Mark E; Bačić, Zlatko

    2016-01-21

    We systematically investigate the manifestations of the condensed-phase environment of the structure II clathrate hydrate in the translation-rotation (TR) dynamics and the inelastic neutron scattering (INS) spectra of an H2 molecule confined in the small dodecahedral cage of the hydrate. The aim is to elucidate the extent to which these properties are affected by the clathrate water molecules beyond the confining cage and the proton disorder of the water framework. For this purpose, quantum calculations of the TR eigenstates and INS spectra are performed for H2 inside spherical clathrate domains of gradually increasing radius and the number of water molecules ranging from 20 for the isolated small cage to more than 1800. For each domain size, several hundred distinct hydrogen-bonding topologies are constructed in order to simulate the effects of the proton disorder. Our study reveals that the clathrate-induced splittings of the j = 1 rotational level and the translational fundamental of the guest H2 are influenced by the condensed-phase environment to a dramatically different degree, the former very strongly and the latter only weakly. PMID:26727217

  1. Phases and Phase Changes of Mixed Organic/Inorganic Model Systems of Tropospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Marcolli, C.; Krieger, U. K.; Zardini, A. A.; Zobrist, B.; Zuend, A.; Luo, B. P.; Peter, T.

    2006-12-01

    Knowledge of the physical state of tropospheric aerosols is important for an adequate description of cloud formation, heterogeneous and multiphase chemistry, and the aerosol's radiative properties. We will present and discuss laboratory experiments on bulk aerosol model mixtures and micron-sized particles consisting of polyols, polyethylene glycol or dicarboxylic acids mixed with ammonium sulfate. Depending on the exact composition and relative humidity, these mixtures form liquid-one-phase or two-phase systems plus additional solid phases. Whilst the organic matter in ambient aerosols is expected to be predominantly present in the form of liquid or amorphous phases, the inorganic salts may still undergo deliquescence and efflorescence as a function of relative humidity. Moreover, they may induce phase separations into a predominantly organic and an inorganic aqueous phase. In the absence of solid phases, the water uptake and release of the investigated micron-sized particles was usually well described by the Zdanovskii-Stokes-Robinson (ZSR) approach. However, this model became inaccurate when solid phases were present. Moreover, it is not able to account for liquid-liquid phase separations due to the salting-out effects of the investigated inorganic salts. While most organics participate in liquid phases some organic substances are abundant enough in the particles to form crystalline solids that might act as ice nuclei. We show that this is the case for oxalic acid.

  2. Phased Antenna Array for Global Navigation Satellite System Signals

    NASA Technical Reports Server (NTRS)

    Turbiner, Dmitry (Inventor)

    2015-01-01

    Systems and methods for phased array antennas are described. Supports for phased array antennas can be constructed by 3D printing. The array elements and combiner network can be constructed by conducting wire. Different parameters of the antenna, like the gain and directivity, can be controlled by selection of the appropriate design, and by electrical steering. Phased array antennas may be used for radio occultation measurements.

  3. SPS phase control system performance via analytical simulation

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.; Booth, R. W. D.

    1979-01-01

    A solar power satellite transmission system which incorporates automatic beam forming, steering, and phase control is discussed. The phase control concept centers around the notation of an active retrodirective phased array as a means of pointing the beam to the appropriate spot on Earth. The transmitting antenna (spacetenna) directs the high power beam so that it focuses on the ground-based receiving antenna (rectenna). A combination of analysis and computerized simulation was conducted to determine the far field performance of the reference distribution system, and the beam forming and microwave power generating systems.

  4. Offline solid phase microextraction sampling system

    DOEpatents

    Harvey, Chris A.

    2008-12-16

    An offline solid phase microextraction (SPME) sampling apparatus for enabling SPME samples to be taken a number of times from a previously collected fluid sample (e.g. sample atmosphere) stored in a fused silica lined bottle which keeps volatile organics in the fluid sample stable for weeks at a time. The offline SPME sampling apparatus has a hollow body surrounding a sampling chamber, with multiple ports through which a portion of a previously collected fluid sample may be (a) released into the sampling chamber, (b) SPME sampled to collect analytes for subsequent GC analysis, and (c) flushed/purged using a fluidically connected vacuum source and purging fluid source to prepare the sampling chamber for additional SPME samplings of the same original fluid sample, such as may have been collected in situ from a headspace.

  5. [Effects of different multiple cropping systems on paddy field weed community under long term paddy-upland rotation].

    PubMed

    Yang, Bin-Juan; Huang, Guo-Qin; Xu, Ning; Wang, Shu-Bin

    2013-09-01

    Based on a long term field experiment, this paper studied the effects of different multiple cropping systems on the weed community composition and species diversity under paddy-upland rotation. The multiple cropping rotation systems could significantly decrease weed density and inhibited weed growth. Among the rotation systems, the milk vetch-early rice-late maize --> milk vetchearly maize intercropped with early soybean-late rice (CCSR) had the lowest weed species dominance, which inhibited the dominant weeds and decreased their damage. Under different multiple cropping systems, the main weed community was all composed of Monochoia vaginalis, Echinochloa crusgalli, and Sagittaria pygmae, and the similarity of weed community was higher, with the highest similarity appeared in milk vetch-early rice-late maize intercropped with late soybean --> milk vetch-early maize-late rice (CSCR) and in CCSR. In sum, the multiple cropping rotations in paddy field could inhibit weeds to a certain extent, but attentions should be paid to the damage of some less important weeds.

  6. Energy and the Confused Student V: The Energy/Momentum Approach to Problems Involving Rotating and Deformable Systems

    ERIC Educational Resources Information Center

    Jewett, John W., Jr.

    2008-01-01

    Energy is a critical concept in physics problem-solving, but is often a major source of confusion for students if the presentation is not carefully crafted by the instructor or the textbook. A common approach to problems involving deformable or rotating systems that has been discussed in the literature is to employ the work-kinetic energy theorem…

  7. Technology verification phase. Dynamic isotope power system. Final report

    SciTech Connect

    Halsey, D.G.

    1982-03-10

    The Phase I requirements of the Kilowatt Isotope Power System (KIPS) program were to make a detailed Flight System Conceptual Design (FSCD) for an isotope fueled organic Rankine cycle power system and to build and test a Ground Demonstration System (GDS) which simulated as closely as possible the operational characteristics of the FSCD. The activities and results of Phase II, the Technology Verification Phase, of the program are reported. The objectives of this phase were to increase system efficiency to 18.1% by component development, to demonstrate system reliability by a 5000 h endurance test and to update the flight system design. During Phase II, system performance was improved from 15.1% to 16.6%, an endurance test of 2000 h was performed while the flight design analysis was limited to a study of the General Purpose Heat Source, a study of the regenerator manufacturing technique and analysis of the hardness of the system to a laser threat. It was concluded from these tests that the GDS is basically prototypic of a flight design; all components necessary for satisfactory operation were demonstrated successfully at the system level; over 11,000 total h of operation without any component failure attested to the inherent reliability of this type of system; and some further development is required, specifically in the area of performance. (LCL)

  8. Engine Data Interpretation System (EDIS), phase 2

    NASA Technical Reports Server (NTRS)

    Cost, Thomas L.; Hofmann, Martin O.

    1991-01-01

    A prototype of an expert system was developed which applies qualitative constraint-based reasoning to the task of post-test analysis of data resulting from a rocket engine firing. Data anomalies are detected and corresponding faults are diagnosed. Engine behavior is reconstructed using measured data and knowledge about engine behavior. Knowledge about common faults guides but does not restrict the search for the best explanation in terms of hypothesized faults. The system contains domain knowledge about the behavior of common rocket engine components and was configured for use with the Space Shuttle Main Engine (SSME). A graphical user interface allows an expert user to intimately interact with the system during diagnosis. The system was applied to data taken during actual SSME tests where data anomalies were observed.

  9. Automated Firearms Identification System (AFIDS), phase 1

    NASA Technical Reports Server (NTRS)

    Blackwell, R. J.; Framan, E. P.

    1974-01-01

    Items critical to the future development of an automated firearms identification system (AFIDS) have been examined, with the following specific results: (1) Types of objective data, that can be utilized to help establish a more factual basis for determining identity and nonidentity between pairs of fired bullets, have been identified. (2) A simulation study has indicated that randomly produced lines, similar in nature to the individual striations on a fired bullet, can be modeled and that random sequences, when compared to each other, have predictable relationships. (3) A schematic diagram of the general concept for AFIDS has been developed and individual elements of this system have been briefly tested for feasibility. Future implementation of such a proposed system will depend on such factors as speed, utility, projected total cost and user requirements for growth. The success of the proposed system, when operational, would depend heavily on existing firearms examiners.

  10. Calculations of Optimal Source Geometry and Controlled Combinatorial Gradients in Fixed- and Rotating-Substrate PVD Systems

    SciTech Connect

    Teeter, G.

    2005-11-01

    Normalized forms of conventional flux-distribution formulas are applied to physical-vapor deposition from open-boat type sources onto static and rotating substrates. For the rotating-substrate case, the deposition geometry that yields optimal film-thickness uniformity for different source-substrate separations is derived empirically. In addition, flux-distribution formulas are used to develop a novel method for combinatorial physical-vapor deposition. With this method, a single deposition system may be used, without modification, to deposit either highly uniform or graded-composition thin-film materials.

  11. Autonomous Flight Safety System - Phase III

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Autonomous Flight Safety System (AFSS) is a joint KSC and Wallops Flight Facility project that uses tracking and attitude data from onboard Global Positioning System (GPS) and inertial measurement unit (IMU) sensors and configurable rule-based algorithms to make flight termination decisions. AFSS objectives are to increase launch capabilities by permitting launches from locations without range safety infrastructure, reduce costs by eliminating some downrange tracking and communication assets, and reduce the reaction time for flight termination decisions.

  12. The behavior of double-diffusive intrusion in a rotating system

    SciTech Connect

    Yoshida, J. ); Nagashima, H. ); Niino, H. )

    1989-04-15

    The effects of Earth's rotation on the stability of a thermohaline front of finite width are studied by means of a linear theory. It is found that when the rotation is present, two different types of unstable modes are possible. When the front is narrow and a Rossby radius of deformation based on Ruddick and Turner's (1979) vertical scale is large in comparison with the width of the front, the fastest growing intrusion is nearly two dimensional (nonrotational mode), and its vertical scale is given by Ruddick and Turner's scale. When the Rossby radius becomes small, in addition to the nonrotational mode there appears another unstable mode (the rotational mode) which has a smaller vertical wave number than the nonrotational mode. With the introduction of rotation, the fastest growing mode has nonzero along-frontal wave number; that is, the intrusion becomes tilted in the along-frontal direction. When the Rossby radius of deformation is sufficiently small in comparison with the width of the front, transition from the nonrotational mode to the rotational one occurs. The transition from nonrotational to rotational mode becomes less pronounced when the width of the front is increased for fixed horizontal density-compensating gradients of temperature and salinity. For a wide front the growth rate and vertical wave number for both modes becomes similar, which agrees with the results of previous studies for infinite fronts that rotation does not modify the behavior of the intrusion except for the occurrence of along-frontal tilt.

  13. A regressed phase analysis for coupled joint systems.

    PubMed

    Wininger, Michael

    2011-01-01

    This study aims to address shortcomings of the relative phase analysis, a widely used method for assessment of coupling among joints of the lower limb. Goniometric data from 15 individuals with spastic diplegic cerebral palsy were recorded from the hip and knee joints during ambulation on a flat surface, and from a single healthy individual with no known motor impairment, over at least 10 gait cycles. The minimum relative phase (MRP) revealed substantial disparity in the timing and severity of the instance of maximum coupling, depending on which reference frame was selected: MRP(knee-hip) differed from MRP(hip-knee) by 16.1±14% of gait cycle and 50.6±77% difference in scale. Additionally, several relative phase portraits contained discontinuities which may contribute to error in phase feature extraction. These vagaries can be attributed to the predication of relative phase analysis on a transformation into the velocity-position phase plane, and the extraction of phase angle by the discontinuous arc-tangent operator. Here, an alternative phase analysis is proposed, wherein kinematic data is transformed into a profile of joint coupling across the entire gait cycle. By comparing joint velocities directly via a standard linear regression in the velocity-velocity phase plane, this regressed phase analysis provides several key advantages over relative phase analysis including continuity, commutativity between reference frames, and generalizability to many-joint systems.

  14. Design of Training Systems Phase I Summary Report.

    ERIC Educational Resources Information Center

    Lindahl, William H.; And Others

    A summary is provided of the status of Phase I of the three-stage project, "Design of Training Systems" (DOTS). The purpose of the overall project is described as being to introduce the technologies of education, psychology, management and operations research into the management of Navy training. Phase I of the effort is designed to provide a…

  15. Transformations of spherical beam shape coefficients in generalized Lorenz-Mie theories through rotations of coordinate systems. IV. Plane waves

    NASA Astrophysics Data System (ADS)

    Gouesbet, G.; Wang, J. J.; Han, Y. P.; G. Grehan

    2010-09-01

    This paper is the fourth of a series devoted to the transformation of beam shape coefficients through rotations of coordinate systems. These coefficients are required to express electromagnetic fields of laser beams in expanded forms, for instance for use in some generalized Lorenz-Mie theories. The main result of Part I has been the theorem of transformation of beam shape coefficients under rotations. Part II dealt with the special case of on-axis axisymmetric beams. Part III dealt with other special cases, namely when the Euler angles specifying the rotation are given some special values. The present Part IV studies another special case, namely the one of plane waves viewed as special on-axis axisymmetric beams, and can therefore be viewed as a special case of Part II. Unexpectedly, it is found that, in general, although plane waves are fairly trivial, their expansions require using non trivial beam shape coefficients, exactly as required when dealing with arbitrary shaped beams.

  16. The Formation Mass of a Binary System via Fragmentation of a Rotating Parent Core with Increasing Total Mass

    NASA Astrophysics Data System (ADS)

    Arreaga-García, G.

    2016-04-01

    We present a set of numerical simulations of the gravitational collapse of a uniform and rotating core, in which azimuthal symmetric mass seeds are initially implemented in order to favor the formation of a dense filament, out of which a binary system may be formed by direct fragmentation. We observe that this binary formation process is diminished when the total mass of the parent core M0 is increased; then we increase the level of the ratio of rotational energy to the gravitational energy, denoted by β, initially supplied to the rotating core, in order to achieve the desired direct fragmentation of the filament. We measure the binary mass Mf obtained from an initial M0 and then show a schematic diagram M0 vs β, where the desired binary configurations are located. We also report some basic physical data of the fragments.

  17. Road Transportable Analytical Laboratory system. Phase 1

    SciTech Connect

    Finger, S.M.; Keith, V.F.; Spertzel, R.O.; De Avila, J.C.; O`Donnell, M.; Vann, R.L.

    1993-09-01

    This developmental effort clearly shows that a Road Transportable Analytical Laboratory System is a worthwhile and achievable goal. The RTAL is designed to fully analyze (radioanalytes, and organic and inorganic chemical analytes) 20 samples per day at the highest levels of quality assurance and quality control. It dramatically reduces the turnaround time for environmental sample analysis from 45 days (at a central commercial laboratory) to 1 day. At the same time each RTAL system will save the DOE over $12 million per year in sample analysis costs compared to the costs at a central commercial laboratory. If RTAL systems were used at the eight largest DOE facilities (at Hanford, Savannah River, Fernald, Oak Ridge, Idaho, Rocky Flats, Los Alamos, and the Nevada Test Site), the annual savings would be $96,589,000. The DOE`s internal study of sample analysis needs projects 130,000 environmental samples requiring analysis in FY 1994, clearly supporting the need for the RTAL system. The cost and time savings achievable with the RTAL system will accelerate and improve the efficiency of cleanup and remediation operations throughout the DOE complex.

  18. Effect of Coordinate Rotation Systems on Calculated Fluxes over a Forest in Complex Terrain: A Comprehensive Comparison

    NASA Astrophysics Data System (ADS)

    Shimizu, Takanori

    2015-08-01

    Seven coordinate rotation systems were compared to determine a suitable system for a forest in complex terrain, using eddy-covariance data for a period of 40 days. The traditional double rotation was set as the standard of comparison with six other fixed coordinate systems, whose coefficients were carefully determined based on wind component data for a two-year period. Differences in total heat fluxes and daytime fluxes calculated from all systems were small, except those from the sector-wise planar fit, which linearly and systematically underestimated the fluxes by about 5 %. The nighttime flux was also underestimated by the sector-wise planar fit, but there was significant scatter in the plots, and the mean difference was 7 %. The standard deviations of the wind components and scalars normalized by the friction velocity and the dynamic parameters were calculated for each system, and the errors from the relationships obtained previously from flat and homogenous terrain were examined. The nighttime normalized standard deviation for scalars agreed better with the relationships after applying the sector-wise planar fit than those calculated by the other systems, although no remarkable difference was found in the daytime data. Therefore, the sector-wise planar fit was not the first choice for our site during daytime based on the energy imbalance, which was mainly caused by underestimating daytime heat fluxes. Double rotation or one of the four systems without the roll rotation process might be superior at our site. However, the offset error in the vertical wind component of the sonic anemometer induced errors of several percent in the fluxes in these systems, which was equivalent to the underestimation using the sector-wise planar fit. Meanwhile, the sector-wise planar fit system might still be the best system for calculating nighttime flux, considering the tendency of the nighttime normalized standard deviations.

  19. Wireless System and Method for Collecting Motion and Non-Motion Related Data of a Rotating System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E. (Inventor); Taylor, Bryant D. (Inventor)

    2011-01-01

    A wireless system for collecting data indicative of a tire's characteristics uses at least one open-circuit electrical conductor in a tire. The conductor is shaped such that it can store electrical and magnetic energy. In the presence of a time-varying magnetic field, the conductor resonates to generate a harmonic response having a frequency, amplitude and bandwidth. A magnetic field response recorder is used to (i) wirelessly transmit the time-varying magnetic field to the conductor, and (ii) wirelessly detect the harmonic response and the frequency, amplitude and bandwidth, associated therewith. The recorder is adapted to be positioned in a location that is fixed with respect to the tire as the tire rotates.

  20. Active phase compensation system for fiber optic holography

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Beheim, Glenn

    1988-01-01

    Fiber optic delivery systems promise to extend the application of holography to severe environments by simplifying test configurations and permitting the laser to be remotely placed in a more benign location. However, the introduction of optical fiber leads to phase stability problems. Environmental effects cause the pathlengths of the fibers to change randomly, preventing the formation of stationary interference patterns which are required for holography. An active phase control system has been designed and used with an all-fiber optical system to stabilize the phase difference between light emitted from two fibers, and to step the phase difference by 90 deg without applying any constraints on the placement of the fibers. The accuracy of the phase steps is shown to be better than 0.02 deg., and a stable phase difference can be maintained for 30 min. This system can be applied to both conventional and electro-optic holography, as well as to any system where the maintenance of an accurate phase difference between two coherent beams is required.

  1. Space law information system design, phase 2

    NASA Technical Reports Server (NTRS)

    Morenoff, J.; Roth, D. L.; Singleton, J. W.

    1973-01-01

    Design alternatives were defined for the implementation of a Space Law Information System for the Office of the General Counsel, NASA. A thesaurus of space law terms was developed and a selected document sample indexed on the basis of that thesaurus. Abstracts were also prepared for the sample document set.

  2. Phase structure rewrite systems in information retrieval

    NASA Technical Reports Server (NTRS)

    Klingbiel, P. H.

    1985-01-01

    Operational level automatic indexing requires an efficient means of normalizing natural language phrases. Subject switching requires an efficient means of translating one set of authorized terms to another. A phrase structure rewrite system called a Lexical Dictionary is explained that performs these functions. Background, operational use, other applications and ongoing research are explained.

  3. Lewis Research Center spin rig and its use in vibration analysis of rotating systems

    NASA Technical Reports Server (NTRS)

    Brown, G. V.; Kielb, R. E.; Meyn, E. H.; Morris, R. E.; Posta, S. J.

    1984-01-01

    The Lewis Research Center spin rig was constructed to provide experimental evaluation of analysis methods developed under the NASA Engine Structural Dynamics Program. Rotors up to 51 cm (20 in.) in diameter can be spun to 16,000 rpm in vacuum by an air motor. Vibration forcing functions are provided by shakers that apply oscillatory axial forces or transverse moments to the shaft, by a natural whirling of the shaft, and by an air jet. Blade vibration is detected by strain gages and optical blade-tip motion sensors. A variety of analogy and digital processing equipment is used to display and analyze the signals. Results obtained from two rotors are discussed. A 56-blade compressor disk was used to check proper operation of the entire spin rig system. A special two-blade rotor was designed and used to hold flat and twisted plates at various setting and sweep angles. Accurate Southwell coefficients have been obtained for several modes of a flat plate oriented parallel to the plane of rotation.

  4. Electromechanical simulation and test of rotating systems with magnetic bearing or piezoelectric actuator active vibration control

    NASA Technical Reports Server (NTRS)

    Palazzolo, Alan B.; Tang, Punan; Kim, Chaesil; Manchala, Daniel; Barrett, Tim; Kascak, Albert F.; Brown, Gerald; Montague, Gerald; Dirusso, Eliseo; Klusman, Steve

    1994-01-01

    This paper contains a summary of the experience of the authors in the field of electromechanical modeling for rotating machinery - active vibration control. Piezoelectric and magnetic bearing actuator based control are discussed.

  5. Solar power satellite system definition study, phase 2.

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A program plan for the Solar Power Satellite Program is presented. The plan includes research, development, and evaluation phase, engineering and development and cost verification phase, prototype construction, and commercialization. Cost estimates and task requirements are given for the following technology areas: (1) solar arrays; (2) thermal engines and thermal systems; (3) power transmission (to earth); (4) large space structures; (5) materials technology; (6) system control; (7) space construction; (8) space transportation; (9) power distribution, and space environment effects.

  6. Integrated thermal treatment system study -- Phase 2 results. Revision 1

    SciTech Connect

    Feizollahi, F.; Quapp, W.J.

    1996-02-01

    This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 1 systems. The alternatives evaluated were: rotary kiln, slagging kiln, plasma furnace, plasma gasification, molten salt oxidation, molten metal waste destruction, steam gasification, Joule-heated vitrification, thermal desorption and mediated electrochemical oxidation, and thermal desorption and supercritical water oxidation. The quantities, and physical and chemical compositions, of the input waste used in the Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr). 28 refs., 88 figs., 41 tabs.

  7. Phase diagram studies on the Na-Mo-O system

    NASA Astrophysics Data System (ADS)

    Gnanasekaran, T.; Mahendran, K. H.; Kutty, K. V. G.; Mathews, C. K.

    1989-06-01

    The phase diagram of the Na-Mo-O ternary system is of interest in interpreting the behaviour of structural materials in the sodium circuits of fast breeder reactors and sodium-filled heat pipes. Experiments involving heating of sodium oxide with molybdenum metal under vacuum, selective removal of oxygen from polymolybdates by reducing them under hydrogen and confirmation of the coexistence of various phase mixtures were conducted in the temperature range of 673 to 923 K. Phase fields involving molybdenum metal, dioxide of molybdenum and ternary compounds were derived from these results. The ternary phase diagram of the Na-Mo-O system was constructed and isothermal cross sections of the phase diagram are presented.

  8. Heat storage system utilizing phase change materials government rights

    DOEpatents

    Salyer, Ival O.

    2000-09-12

    A thermal energy transport and storage system is provided which includes an evaporator containing a mixture of a first phase change material and a silica powder, and a condenser containing a second phase change material. The silica powder/PCM mixture absorbs heat energy from a source such as a solar collector such that the phase change material forms a vapor which is transported from the evaporator to the condenser, where the second phase change material melts and stores the heat energy, then releases the energy to an environmental space via a heat exchanger. The vapor is condensed to a liquid which is transported back to the evaporator. The system allows the repeated transfer of thermal energy using the heat of vaporization and condensation of the phase change material.

  9. Intelligent Robotic Systems Study (IRSS), phase 2

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under the Intelligent Robotics System Study (IRSS) contract, a generalized robotic control architecture was developed for use with the ProtoFlight Manipulator Arm (PFMA). The controller built for the PFMA provides localized position based force control, teleoperation and advanced path recording and playback capabilities. Various hand controllers can be used with the system in conjunction with a synthetic time delay capability to provide a realistic test bed for typical satellite servicing tasks. The configuration of the IRSS system is illustrated and discussed. The PFMA has six computer controllable degrees of freedom (DOF) plus a seventh manually indexable DOF, making the manipulator a pseudo 7 DOF mechanism. Because the PFMA was not developed to operate in a gravity field, but rather in space, it is counter balanced at the shoulder, elbow and wrist and a spring counterbalance has been added near the wrist to provide additional support. Built with long slender intra-joint linkages, the PFMA has a workspace nearly 2 meters deep and possesses sufficient dexterity to perform numerous satellite servicing tasks. The manipulator is arranged in a shoulder-yaw, pitch, elbow-pitch, and wrist-pitch, yaw, roll configuration, with an indexable shoulder roll joint. Digital control of the PFMA is implemented using a variety of single board computers developed by Heurikon Corporation and other manufacturers. The IRSS controller is designed to be a multi-rate, multi-tasking system. Independent joint servos run at a 134 Hz rate and position based impedance control functions at 67 Hz. Autonomous path generation and hand controller inputs are processed at a 33 Hz.

  10. Microgravity fluid management in two-phase thermal systems

    NASA Technical Reports Server (NTRS)

    Parish, Richard C.

    1987-01-01

    Initial studies have indicated that in comparison to an all liquid single phase system, a two-phase liquid/vapor thermal control system requires significantly lower pumping power, demonstrates more isothermal control characteristics, and allows greater operational flexibility in heat load placement. As a function of JSC's Work Package responsibility for thermal management of space station equipment external to the pressurized modules, prototype development programs were initiated on the Two-Phase Thermal Bus System (TBS) and the Space Erectable Radiator System (SERS). JSC currently has several programs underway to enhance the understanding of two-phase fluid flow characteristics. The objective of one of these programs (sponsored by the Microgravity Science and Applications Division at NASA-Headquarters) is to design, fabricate, and fly a two-phase flow regime mapping experiment in the Shuttle vehicle mid-deck. Another program, sponsored by OAST, involves the testing of a two-phase thermal transport loop aboard the KC-135 reduced gravity aircraft to identify system implications of pressure drop variation as a function of the flow quality and flow regime present in a representative thermal system.

  11. Phase structure of one-dimensional interacting Floquet systems. II. Symmetry-broken phases

    NASA Astrophysics Data System (ADS)

    von Keyserlingk, C. W.; Sondhi, S. L.

    2016-06-01

    Recent work suggests that a sharp definition of "phase of matter" can be given for periodically driven "Floquet" quantum systems exhibiting many-body localization. In this work, we propose a classification of the phases of interacting Floquet localized systems with (completely) spontaneously broken symmetries; we focus on the one-dimensional case, but our results appear to generalize to higher dimensions. We find that the different Floquet phases correspond to elements of Z (G ) , the center of the symmetry group in question. In a previous paper [C. W. von Keyserlingk and S. L. Sondhi, preceding paper, Phys. Rev. B 93, 245145 (2016)], 10.1103/PhysRevB.93.245145, we offered a companion classification of unbroken, i.e., paramagnetic phases.

  12. Differentiation of mammalian skeletal muscle cells cultured on microcarrier beads in a rotating cell culture system

    NASA Technical Reports Server (NTRS)

    Torgan, C. E.; Burge, S. S.; Collinsworth, A. M.; Truskey, G. A.; Kraus, W. E.

    2000-01-01

    The growth and repair of adult skeletal muscle are due in part to activation of muscle precursor cells, commonly known as satellite cells or myoblasts. These cells are responsive to a variety of environmental cues, including mechanical stimuli. The overall goal of the research is to examine the role of mechanical signalling mechanisms in muscle growth and plasticity through utilisation of cell culture systems where other potential signalling pathways (i.e. chemical and electrical stimuli) are controlled. To explore the effects of decreased mechanical loading on muscle differentiation, mammalian myoblasts are cultured in a bioreactor (rotating cell culture system), a model that has been utilised to simulate microgravity. C2C12 murine myoblasts are cultured on microcarrier beads in a bioreactor and followed throughout differentiation as they form a network of multinucleated myotubes. In comparison with three-dimensional control cultures that consist of myoblasts cultured on microcarrier beads in teflon bags, myoblasts cultured in the bioreactor exhibit an attenuation in differentiation. This is demonstrated by reduced immunohistochemical staining for myogenin and alpha-actinin. Western analysis shows a decrease, in bioreactor cultures compared with control cultures, in levels of the contractile proteins myosin (47% decrease, p < 0.01) and tropomyosin (63% decrease, p < 0.01). Hydrodynamic measurements indicate that the decrease in differentiation may be due, at least in part, to fluid stresses acting on the myotubes. In addition, constraints on aggregate size imposed by the action of fluid forces in the bioreactor affect differentiation. These results may have implications for muscle growth and repair during spaceflight.

  13. Microfabricated Gas Phase Chemical Analysis Systems

    SciTech Connect

    Casalnuovo, Stephen A.; Frye-Mason, Gregory C; Heller, Edwin J.; Hietala, Vincent M.; Kottenstette, Richard J.; Lewis, Patrick R.; Manginell, Ronald P.; Matzke, Carolyn M.; Wong, C. Channy

    1999-08-02

    A portable, autonomous, hand-held chemical laboratory ({mu}ChemLab{trademark}) is being developed for trace detection (ppb) of chemical warfare (CW) agents and explosives in real-world environments containing high concentrations of interfering compounds. Microfabrication is utilized to provide miniature, low-power components that are characterized by rapid, sensitive and selective response. Sensitivity and selectivity are enhanced using two parallel analysis channels, each containing the sequential connection of a front-end sample collector/concentrator, a gas chromatographic (GC) separator, and a surface acoustic wave (SAW) detector. Component design and fabrication and system performance are described.

  14. Phase I --system scoping and feasibility studies

    SciTech Connect

    Not Available

    1993-03-01

    The National Energy Strategy (NES) calls for a balanced program of greater energy efficiency, use of alternative fuels, and the environmentally responsible development of all the U.S. energy resources. Consistent with the NES, a Department of Energy (DOE) program has been created to develop Advanced Turbine Systems (ATS). The objective of this 10-year program is to develop natural gas-fired base load power plants that will have cycle efficiencies greater than 60% (LHV), be environmentally superior to current technology, and also be cost competitive.

  15. Advanced two-phase heat transfer systems

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore D.

    1992-01-01

    Future large spacecraft, such as the Earth Observing System (EOS) platforms, will require a significantly more capable thermal control system than is possible with current 'passive' technology. Temperatures must be controlled much more tightly over a larger surface area. Numerous heat load sources will often be located inside the body of the spacecraft without a good view to space. Power levels and flux densities may be higher than can be accommodated with traditional technology. Integration and ground testing will almost certainly be much more difficult with such larger, more complex spacecraft. For these and similar reasons, the Goddard Space Flight Center (GSFC) has been developing a new, more capable thermal control technology called capillary pumped loops (CPL's). CPL's represent an evolutionary improvement over heat pipes; they can transport much greater quantities of heat over much longer distances and can serve numerous heat load sources. In addition, CPL's can be fabricated into large cold plates that can be held to tight thermal gradients. Development of this technology began in the early 1980's and is now reaching maturity. CPL's have recently been baselined for the EOS-AM platform (1997 launch) and the COMET spacecraft (1992 launch). This presentation describes this new technology and its applications. Most of the viewgraphs are self descriptive. For those that are less clear additional comments are provided.

  16. Advanced two-phase heat transfer systems

    NASA Astrophysics Data System (ADS)

    Swanson, Theodore D.

    1992-10-01

    Future large spacecraft, such as the Earth Observing System (EOS) platforms, will require a significantly more capable thermal control system than is possible with current 'passive' technology. Temperatures must be controlled much more tightly over a larger surface area. Numerous heat load sources will often be located inside the body of the spacecraft without a good view to space. Power levels and flux densities may be higher than can be accommodated with traditional technology. Integration and ground testing will almost certainly be much more difficult with such larger, more complex spacecraft. For these and similar reasons, the Goddard Space Flight Center (GSFC) has been developing a new, more capable thermal control technology called capillary pumped loops (CPL's). CPL's represent an evolutionary improvement over heat pipes; they can transport much greater quantities of heat over much longer distances and can serve numerous heat load sources. In addition, CPL's can be fabricated into large cold plates that can be held to tight thermal gradients. Development of this technology began in the early 1980's and is now reaching maturity. CPL's have recently been baselined for the EOS-AM platform (1997 launch) and the COMET spacecraft (1992 launch). This presentation describes this new technology and its applications. Most of the viewgraphs are self descriptive. For those that are less clear additional comments are provided.

  17. Phase-factor-dependent symmetries and quantum phases in a three-level cavity QED system

    PubMed Central

    Fan, Jingtao; Yu, Lixian; Chen, Gang; Jia, Suotang

    2016-01-01

    Unlike conventional two-level particles, three-level particles may support some unitary-invariant phase factors when they interact coherently with a single-mode quantized light field. To gain a better understanding of light-matter interaction, it is thus necessary to explore the phase-factor-dependent physics in such a system. In this report, we consider the collective interaction between degenerate V-type three-level particles and a single-mode quantized light field, whose different components are labeled by different phase factors. We mainly establish an important relation between the phase factors and the symmetry or symmetry-broken physics. Specifically, we find that the phase factors affect dramatically the system symmetry. When these symmetries are breaking separately, rich quantum phases emerge. Finally, we propose a possible scheme to experimentally probe the predicted physics of our model. Our work provides a way to explore phase-factor-induced nontrivial physics by introducing additional particle levels. PMID:27139573

  18. A phase-modulated laser system of ultra-low phase noise for compact atom interferometers

    NASA Astrophysics Data System (ADS)

    Lee, Ki-Se; Kim, Jaewan; Lee, Sang-Bum; Park, Sang Eon; Kwon, Taek Yong

    2015-07-01

    A compact and robust laser system is essential for mobile atom interferometers. Phase modulation can provide the two necessary phase-coherent frequencies without sophisticated phase-locking between two different lasers. However, the additional laser frequencies generated can perturb the atom interferometer. In this article, we report on a novel method to produce a single high-power laser beam composed of two phase-coherent sidebands without the perturbing carrier mode. Light from a diode laser is phase-modulated by using a fiber-coupled electro-optic modulator driven at 3.4 GHz and passes through a Fabry-Perot cavity with a 6.8 GHz free spectral range. The cavity filters the carrier mode to leave the two first-order sidebands for the two-photon Raman transition between the two hyperfine ground states of 87Rb. The laser beam is then fed to a single tapered amplifier, and the two sidebands are both amplified without mode competition. The phase noise is lower than that of a state-of-the-art optically phase-locked external-cavity diode laser (-135 dBrad2/Hz at 10 kHz) at frequencies above 10 Hz. This technique can be used in all-fiber-based laser systems for future mobile atom interferometers.

  19. Comments on Frequency Swept Rotating Input Perturbation Techniques and Identification of the Fluid Force Models in Rotor/bearing/seal Systems and Fluid Handling Machines

    NASA Technical Reports Server (NTRS)

    Muszynska, Agnes; Bently, Donald E.

    1991-01-01

    Perturbation techniques used for identification of rotating system dynamic characteristics are described. A comparison between two periodic frequency-swept perturbation methods applied in identification of fluid forces of rotating machines is presented. The description of the fluid force model identified by inputting circular periodic frequency-swept force is given. This model is based on the existence and strength of the circumferential flow, most often generated by the shaft rotation. The application of the fluid force model in rotor dynamic analysis is presented. It is shown that the rotor stability is an entire rotating system property. Some areas for further research are discussed.

  20. Quadruple-junction lattice coherency and phase separation in a binary-phase system

    PubMed Central

    Chung, Sung-Yoon; Choi, Si-Young; Kim, Jin-Gyu; Kim, Young-Min

    2015-01-01

    If each phase has an identical crystal structure and small misfit in the lattice parameters in a binary-phase crystalline system, coherent phase boundaries usually form during separation. Although there have been numerous studies on the effect of coherency elastic energy, no attempt has been made to demonstrate how the phase-separation behaviour varies when multiple interfaces meet at a junction. Here we show that a comprehensively different phase-separation morphology is induced, to release the high coherency strain confined to quadruple junctions. High-temperature in-situ transmission electron microscopy reveals that phase boundaries with a new crystallographic orientation emerge over twinned crystals to provide strain relaxation at quadruple junctions. The high coherency strain and the formation of different phase boundaries can be understood in terms of the force equilibrium between interface tensions at a junction point. Visualizing the quadruple points at atomic resolution, our observations emphasize the impact of multiple junctions on the morphology evolution during phase separation. PMID:26346223