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Sample records for phase rotator system

  1. Berry's phase in rotating systems

    NASA Astrophysics Data System (ADS)

    Cui, Shi-Min; Xu, Hong-Hua

    1991-09-01

    It is shown that, in addition to the Aharonov-Bohm-like phase studied previously [M. V. Berry, Proc. R. Soc. London Ser. A 392, 45 (1984); Y. Aharakov and J. Anandan, Phys. Rev. Lett. 58, 1593 (1987); C. H. Tsai and D. Neilson, Phys. Rev. A 37, 619 (1988)], Berry's topological phase also appears for purely mechanical reasons in systems rotating at slowly-time-varying angular velocity about a fixed center. A possible experiment to probe this manifestation of Berry's phase is discussed.

  2. 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

  3. PAPR Reduction for PCC-OFDM Systems Using Neural Phase Rotator

    NASA Astrophysics Data System (ADS)

    Ohta, Masaya; Yamada, Hideyuki; Yamashita, Katsumi

    This paper proposes a novel Orthogonal frequency-division multiplexing (OFDM) system based on polynomial cancellation coded OFDM (PCC-OFDM). This proposed system can reduce peak-to-average power ratio (PAPR) by our neural phase rotator and it does not need any side information to transmit phase rotation factors. Moreover, this system can compensate the common phase error (CPE) by a proposed technique which allows estimating frequency offset at receiver. From numerical experiments, it is shown that our system can reduce PAPR and ICI at the same time and improve BER performance effectively.

  4. Phase-locked servo system. [for synchronizing the rotation of slip ring assembly

    NASA Technical Reports Server (NTRS)

    Burdin, C. (Inventor)

    1974-01-01

    A phase lock servo system is described for synchronizing the rotation of a slip ring assembly with the rotation of an air bearing table so that a minimum of torque will be imparted through cables extending from the slip ring assembly to the air bearing table as such is rotated. The system includes two servo loops. The first servo loop includes a rate gyroscope carried on the air bearing table which generates a signal through a summing junction to be compared with a signal coming from a tachometer coupled to the slip ring assembly. The corrective signal is applied to a torque motor for rotating the slip ring assembly. The second servo loop includes a pair of photo detector cells which generate pulses responsive to the rotation of the air bearing table and slip ring assembly which are fed through a phase detector, and a variable gain amplifier to the summing junction circuit to provide a fine adjustment for rotating the slip ring assembly.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. 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

  8. Development of simultaneous measurement system of birefringence, optical rotational power, and transmission spectra for chiral liquid crystal phases

    NASA Astrophysics Data System (ADS)

    Feng, Zhengyu; Ishikawa, Ken

    2016-05-01

    A novel experimental setup used to measure the important optical properties of liquid crystal materials is proposed. The setup allows us to measure electric-field-induced birefringence, optical rotational power, and transmission spectra consecutively. This system can be widely applied to characterize liquid crystal materials including blue phases, ferroelectric liquid crystals, and other chiral phases. We adopted this system to study the phase transition behavior of a V-shape switching ferroelectric liquid crystal mixture and made an important correction of experimental results previously reported by Sandhya et al. [ Europhys. Lett. 90, 56005 (2010)]. This finding proves the advantage of this system compared with the measurement method using individual systems.

  9. 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

  10. 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. PMID:25790029

  11. Rotational chaos in dissipative systems

    NASA Astrophysics Data System (ADS)

    Casdagli, Martin

    1988-01-01

    An investigation is made into chaotic attractors arising from a quasiperiodic transition to chaos, using a quantity called the rotation interval. The rotation interval describes the short term rotation rates available to the attractor. We present algorithms to calculate it given an appropriate map, differential equation or time series. We find that the rotation interval has a very robust parameter dependence: its endpoints are almost always phase locked. Our numerical ideas are based on the theory of dissipative twist maps, which is reviewed. This theory is also used to prove a theorem about the non-existence of certain strange attractors in nearly conservative systems. Finally, an investigation is made into the relationship between the rotation interval and topological entropy, and the breakup of invariant circles.

  12. 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.

  13. 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.

  14. Chiral symmetry in rotating systems

    NASA Astrophysics Data System (ADS)

    Malik, Sham S.

    2015-08-01

    The triaxial rotating system at critical angular momentum I ≥Iband exhibits two enatiomeric (the left- and right-handed) forms. These enatiomers are related to each other through dynamical chiral symmetry. The chiral symmetry in rotating system is defined by an operator χ ˆ =Rˆy (π) T ˆ, which involves the product of two distinct symmetries, namely, continuous and discrete. Therefore, new guidelines are required for testing its commutation with the system Hamiltonian. One of the primary objectives of this study is to lay down these guidelines. Further, the possible impact of chiral symmetry on the geometrical arrangement of angular momentum vectors and investigation of observables unique to nuclear chiral-twins is carried out. In our model, the angular momentum components (J1, J2, J3) occupy three mutually perpendicular axes of triaxial shape and represent a non-planar configuration. At certain threshold energy, the equation of motion in angular momentum develops a second order phase transition and as a result two distinct frames (i.e., the left- and right-handed) are formed. These left- and right-handed states correspond to a double well system and are related to each other through chiral operator. At this critical angular momentum, the centrifugal and Coriolis interactions lower the barrier in the double well system. The tunneling through the double well starts, which subsequently lifts the degeneracy among the rotational states. A detailed analysis of the behavior of rotational energies, spin-staggering, and the electromagnetic transition probabilities of the resulting twin-rotational bands is presented. The ensuing model results exhibit similarities with many observed features of the chiral-twins. An advantage of our formalism is that it is quite simple and it allows us to pinpoint the understanding of physical phenomenon which lead to chiral-twins in rotating systems.

  15. Superconducting magnets for muon capture and phase rotation

    SciTech Connect

    Green, M.A.; Weggel, R.J.

    1999-07-26

    There are two key systems that must operate efficiently, in order for a muon collider to be a viable option for high energy physics. These systems are the muon production and collection system and the muon cooling system. Both systems require the use of high field superconducting solenoid magnets. This paper describes the supcrconducting solenoid system used for the capture and phase rotation of the pions that are produced on a target in a high intensity proton beam.

  16. Faraday rotation echo spectroscopy of phase transitions

    NASA Astrophysics Data System (ADS)

    Chen, Shaowen; Liu, Renbao

    2013-03-01

    Faraday rotation is widely used to study magnetic dynamics. We designed a scheme of Faraday rotation echo spectroscopy (FRES) that can be used to study spin noise dynamics in transparent materials by measuring the fluctuation of Faraday rotation angle. The FRES suppresses the static part of the noise and reveal the quantum fluctuations at relatively high temperature, which shares the same idea of the spin echo technique in nuclear magnetic resonance (NMR). We tested our theory on a rare-earth compound LiHoF4. The quantum fluctuations obtained by FRES give an enhanced feature at the phase boundary. The FRES can be straightforwardly generalized to more complicated configurations that correspond to more complex dynamical decoupling sequences in NMR and electron spin resonance, which may give us more extensive information on the structural and dynamical properties of magnetic materials. This work was supported by Hong Kong RGC 402410 and CUHK FIS.

  17. 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).

  18. 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.

  19. 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...

  20. 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.

  1. Decoupling translational and rotational effects on the phase synchronization of rotating helices

    NASA Astrophysics Data System (ADS)

    Tu, Jonathan H.; Arcak, Murat; Maharbiz, Michel M.

    2015-02-01

    The locomotion of swimming microorganisms often relies on synchronized motions; examples include the bundling of flagella and metachronal coordination of cilia. It is now generally accepted that such behavior can result from hydrodynamic interactions alone. In this paper we consider the interactions between two side-by-side rigid helices driven by constant torques. We use the method of regularized Stokeslets to simulate an end-pinned model, in which restoring forces and torques are applied at one end of each helix. This allows us to decouple the respective effects of translation and rotation on phase synchronization. We find that while translational freedom leads to synchrony, rotational freedom can result in either synchrony or antisynchrony, depending on the stiffness of the system. In addition, we characterize the nature of the physical mechanisms driving these behaviors, focusing on the individual effects of each applied force and torque. For translational freedom, there is a single underlying mechanism in which the interaction forces indirectly influence the helix rotation rates. Multiple mechanisms are at play for rotational freedom: the interaction torques may exert either direct or indirect influence depending on stiffness. These characterizations are important to the future development of reduced-order models, which should capture not only the expected end behaviors (synchrony or antisynchrony), but also the nature of the driving mechanisms.

  2. Phase-space rotations and orbital Stokes parameters.

    PubMed

    Alieva, Tatiana; Bastiaans, Martin J

    2009-02-15

    We introduce the orbital Stokes parameters as a linear combination of a beam's second-order moments. Similar to the ones describing the field polarization and associated with beam energy and its spin angular momentum, the orbital Stokes parameters are related to the total beam width and its orbital angular momentum. We derive the transformation laws for these parameters during beam propagation through first-order optical systems associated with phase-space rotations. The values of the orbital Stokes parameters for Gaussian modes and arbitrary fields expressed as their linear superposition are obtained. PMID:19373324

  3. 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

  4. 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.

  5. 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.

  6. Crop Rotation in Row Crop Production Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop rotation is a system of growing different kinds of crops in recurrent succession on the same land. Thus, in the strictest sense, crop rotation is more than just changing crops from year to year based on current economic situations. Rather, it is a long-term plan for soil and farm management. Cr...

  7. A rotating target wheel system for Gammasphere

    SciTech Connect

    Greene, John P.; Falout, Joseph W.; Lister, Christopher J.; Nardi, Bruce G.; Fox, John D.

    1999-06-10

    A description is given for a low-mass, rotating target wheel to be used within the Gammasphere target chamber. This system was developed for experiments employing high beam currents in order to extend lifetimes of targets using low-melting point target material. The design is based on a previously successful implementation of rotating target wheels for the Argonne Positron Experiment (APEX) as well as the Fragment Mass Analyser (FMA) at ATLAS (Argonne Tandem Linac Accelerator System). A brief history of these rotating target wheel systems is given as well as a discussion on target preparation and performance.

  8. 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.

  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

    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 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

  12. 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. PMID:26974609

  13. Voltage Controlled Geometric Phase Rotation in ^{208}Pb^{19}F.

    NASA Astrophysics Data System (ADS)

    Furneaux, J. E.; Shafer-Ray, Neil; Coker, J.; Rupasinghe, P. M.; McRaven, C. P.

    2013-06-01

    Many theoretical publications have investigated the impact of the geometric phase on measurements of the e-EDM. However, there has been surprisingly little quantitative comparison of these models with experiment. Here we create a quantum beat experiment that starts with an optical pump and ends with an optical probe of ^{208}Pb^{19}F. This measurement includes the ability to control a geometric phase variation of the molecular alignment by applying an appropriate bias voltage. These experiments will then used to test the accuracy of our model calculations of geometric phase rotation.

  14. Work and energy in rotating systems

    NASA Astrophysics Data System (ADS)

    Manjarres, Diego A.; Herrera, William J.; Diaz, Rodolfo A.

    2013-08-01

    The way in which forces transform from an inertial reference frame to a non-inertial rotating frame is well studied in the literature. However, the treatment of the work-energy theorem in rotating systems is not considered in textbooks. In this paper, we show that the work-energy theorem can still be applied to a closed system of particles in a rotating reference frame, as long as the work of fictitious forces is properly included in the formalism. The Coriolis force does not contribute to the work coming from fictitious forces. It is remarkable that real forces that do no work in an inertial reference frame can do work in the rotating reference frame and vice versa.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Life prediction systems for critical rotating components

    NASA Technical Reports Server (NTRS)

    Cunningham, Susan E.

    1993-01-01

    With the advent of advanced materials in rotating gas turbine engine components, the methodologies for life prediction of these parts must also increase in sophistication and capability. Pratt & Whitney's view of generic requirements for composite component life prediction systems are presented, efforts underway to develop these systems are discussed, and industry participation in key areas requiring development is solicited.

  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. Design and implementation of hybrid CORDIC algorithm based on phase rotation estimation for NCO.

    PubMed

    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

  2. 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...

  3. Mechanical and Thermal Prototype Testing for a Rotatable Collimator for the LHC Phase II Collimation Upgrade

    SciTech Connect

    Smith, Jeffrey Claiborne; Doyle, Eric; Keller, Lewis; Lundgren, Steven; Markiewicz, Thomas Walter; /SLAC

    2010-08-26

    The Phase II upgrade to the LHC collimation system calls for complementing the robust Phase I graphite collimators with high Z, low impedance Phase II collimators. The design for the collimation upgrade has not been finalized. One option is to use metallic rotatable collimators and testing of this design will be discussed here. The Phase II collimators must be robust in various operating conditions and accident scenarios. A prototype collimator jaw has been tested for both mechanical and thermal compliance with the design goals. Thermal expansion bench-top tests are compared to ANSYS simulation results.

  4. Phase mixed rotation magnetoconvection and Taylor's condition III. Wave trains

    NASA Astrophysics Data System (ADS)

    Ewen, Susan A.; Soward, Andrew M.

    Nonlinear amplitude equations governing the radial modulation of quasi-geostrophic convective rolls, which occur in a rapidly rotating self-gravitating sphere permeated by a weak azimuthal magnetic field (small Elsasser number), were derived in Part I. Stationary and travelling pulse solutions were obtained in Part II. That analysis is extended here; wave train solutions are sought and their stability tested. Special features of the equations include: nonlinear diffusion and dispersion; also phase mixing, which leads to a lack of translational invariance of the system. In spite of the latter, the underlying structure of the wave trains sought is spatially periodic on a length L, but modulated by a time dependent Floquet exponent. Consequently, a Fourier representation is employed and the time evolution of the Fourier coefficients is determined numerically. It is shown that pulses confined to lengths l(< L) can be superimposed non-interactively to form wave trains. The numerical demonstration relies on establishing that the pseudo-energy based on the time averaged wave train amplitude coincides with the corresponding pulse energy E calculated in Part II. When l and L are comparable some pulse interaction can be inferred. Available numerical evidence suggests that wave trains, and by implication pulses, are unstable. The geophysical implications are discussed. All finite amplitude solutions pertain to the Ekman regime in which the modified Taylor's condition is satisfied by small magnetic field perturbations. Only in the infinite amplitude limit do the solutions determine true Taylor states. It is anticipated that following instability in the Ekman regime convection equilibrates in some large amplitude Taylor state, which is determined when additional ageostrophic effects are taken into account. Analysis of that state lies outside the range of validity of our amplitude equations.

  5. Ultrasound phase rotation beamforming on multi-core DSP.

    PubMed

    Ma, Jieming; Karadayi, Kerem; Ali, Murtaza; Kim, Yongmin

    2014-01-01

    Phase rotation beamforming (PRBF) is a commonly-used digital receive beamforming technique. However, due to its high computational requirement, it has traditionally been supported by hardwired architectures, e.g., application-specific integrated circuits (ASICs) or more recently field-programmable gate arrays (FPGAs). In this study, we investigated the feasibility of supporting software-based PRBF on a multi-core DSP. To alleviate the high computing requirement, the analog front-end (AFE) chips integrating quadrature demodulation in addition to analog-to-digital conversion were defined and used. With these new AFE chips, only delay alignment and phase rotation need to be performed by DSP, substantially reducing the computational load. We implemented the delay alignment and phase rotation modules on a Texas Instruments C6678 DSP with 8 cores. We found it takes 200 μs to beamform 2048 samples from 64 channels using 2 cores. With 4 cores, 20 million samples can be beamformed in one second. Therefore, ADC frequencies up to 40 MHz with 2:1 decimation in AFE chips or up to 20 MHz with no decimation can be supported as long as the ADC-to-DSP I/O requirement can be met. The remaining 4 cores can work on back-end processing tasks and applications, e.g., color Doppler or ultrasound elastography. One DSP being able to handle both beamforming and back-end processing could lead to low-power and low-cost ultrasound machines, benefiting ultrasound imaging in general, particularly portable ultrasound machines. PMID:23706261

  6. Monte Carlo simulation of the crystal structure of the rotator phase of n-paraffins. II. Effects of rotation and translation of the rigid molecules

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takashi

    1988-08-01

    Structures and molecular motions in the rotator phases of n-paraffins are simulated by use of the Monte Carlo method—both rotational and translational degrees of freedom of the molecules being taken into account. Molecules of rigid trans-planar structure are assumed to be placed in a two-dimensional orthorhombic or orthohexagonal lattice with lattice parameters a and b. A model of the nearly continuous molecular motion is adopted in this work; each molecule is assumed to have 36 discrete orientations (in 10° intervals) and 10 discrete translations (in 0.128 Å intervals) around and along the molecular axis, respectively. Molecular packing modes in various lattice systems of different a/b values are examined ranging from that of the ordinary orthorhombic phase (a/b=1.50) to that of the rotator-II (R-II) phase (a/b=31/2). It is found that the crystals in the rotator phases are generally composed of many domains within which molecules are packed more or less in order. In the rotator-I (R-I) phase, fairly large structural changes are observed with the change in a/b value; the structure of the R-I phase reported in our previous MC work should be slightly modified. The structure of the R-II phase, on the other hand, is found to be essentially the same as that of our previous MC work. Modes of the molecular motion in the R-II phase are studied by monitoring the time evolution of the rotational and translational states of all molecules in the system. It is found that the molecules are making fairly active rotational oscillation around one of the six equivalent directions connecting nearest neighbor molecular pairs. The molecules are also making sporadic large rotations to the different directions. The translational motion of the molecules is found to be very active and evidently independent of the rotational motion. The overall molecular motions in the rotator phase are found to be described in terms of the movement of the boundaries of the ordered domains.

  7. 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.

  8. 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.

  9. Models of cuspy triaxial stellar systems - IV. Rotating systems

    NASA Astrophysics Data System (ADS)

    Carpintero, D. D.; Muzzio, J. C.

    2016-06-01

    We built two self-consistent models of triaxial, cuspy, rotating stellar systems adding rotation to non-rotating models presented in previous papers of this series. The final angular velocity of the material is not constant and varies with the distance to the centre and with the height over the equator of the systems, but the figure rotation is very uniform in both cases. Even though the addition of rotation to the models modifies their original semi-axes ratios, the final rotating models are considerably flattened and triaxial. An analysis of the orbital content of the models shows that about two-thirds of their orbits are chaotic yet the models are very stable over intervals of the order of one Hubble time. The bulk of regular orbits are short-axis tubes, while long-axis tubes are replaced by tubes whose axes lie on the short-long axes plane, but do not coincide with the major axis. Other types of regular orbits that do not appear in non-rotating systems, like horseshoes and orbits that cross themselves, are also found in the present models. Finally, our frequency maps show empty regions where studies of orbits on fixed potentials found orbits, a likely consequence of the self-consistency of our models that excludes them.

  10. Dynamics of rotating multicomponent turbomachinery systems

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles

    1993-01-01

    The ultimate objective of turbomachinery vibration analysis is to predict both the overall, as well as component dynamic response. To accomplish this objective requires complete engine structural models, including multistages of bladed disk assemblies, flexible rotor shafts and bearings, and engine support structures and casings. In the present approach each component is analyzed as a separate structure and boundary information is exchanged at the inter-component connections. The advantage of this tactic is that even though readily available detailed component models are utilized, accurate and comprehensive system response information may be obtained. Sample problems, which include a fixed base rotating blade and a blade on a flexible rotor, are presented.

  11. A rotating inertial navigation system with the rotating axis error compensation consisting of fiber optic gyros

    NASA Astrophysics Data System (ADS)

    Zha, Feng; Hu, Bai-qing; Qin, Fang-jun; Luo, Yin-bo

    2012-03-01

    An effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system (RINS). The accuracy of single-axial RINS is limited by the errors on the rotating axis. A novel inertial measurement unit (IMU) scheme with error compensation for the rotating axis of fiber optic gyros (FOG) RINS is presented. In the scheme, two couples of inertial sensors with similar error characteristics are mounted oppositely on the rotating axes to compensate the sensors error. Without any change for the rotation cycle, this scheme improves the system's precision and reliability, and also offers the redundancy for the system. The results of 36 h navigation simulation prove that the accuracy of the system is improved notably compared with normal strapdown INS, besides the heading accuracy is increased by 3 times compared with single-axial RINS, and the position accuracy is improved by 1 order of magnitude.

  12. 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.

  13. 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

  14. 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

  15. System of invariant correlation to rotation using a ring mask

    NASA Astrophysics Data System (ADS)

    Solorza, Selene; Álvarez-Borrego, Josué; Kober, Vitaly

    2008-08-01

    A new rotational invariance computational filter is presented. The filter was applied to a problem image, in this case, an image of 256 by 256 pixels of black background with a centered white Arial letter. The complete alphabet is represented in those images. The image is rotated one degree by one degree until complete 360 degrees; hence, for each alphabet letter we are generating 360 images. To achieve the rotational invariance, first of all, a translational invariance is applied and then a 256 by 256 binary mask of concentric circular rings of three pixels of thickness and separation is used. The sum of the information in the circular rings represents the signature of the image. The average of the signature of the 360 images of a selected letter is the filter used to compute the phase correlation with all alphabet letter and their rotated images. The confidence level is calculated by the mean value with two standard errors (2SE) of those 360 correlation values for each letter. The confidence level shows that this system works efficiently on the discrimination between letters.

  16. Rotation angle system of bidirectional reflectance distribution function measurement device

    NASA Astrophysics Data System (ADS)

    Wu, Houping; Feng, Guojin; Zheng, Chundi; Li, Ping; Wang, Yu

    2015-10-01

    This article described the rotation angle system of the bidirectional reflectance distribution function (BRDF) measurement device. A high-precision multidimensional angle platform device is built. The rotation angle system uses two scanning rotational mechanical arms and a two-dimensional coaxial turntable mechanical structure, each rotational axis are driven by high-power motor and completed closed-loop control with high-precision encoder. Rotation of the motors can be automatically measured in accordance with point by the control software. The detecting arm can be rotated to measure any point in hemisphere space, the rotary range of light arm is +/- 90 °, the rotary range of sample stage is 360 ° and the angular resolution is 0.01°. The rotation angle system meets the absolute positioning hemisphere space requirements of BRDF device. The experimental result shows that the rotation angle system met the high-precision positioning requirements for the BRDF absolute measurement.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Turbulent plane Couette flow subject to strong system rotation

    NASA Astrophysics Data System (ADS)

    Bech, Knut H.; Andersson, Helge I.

    1997-09-01

    System rotation is known to substantially affect the mean flow pattern as well as the turbulence structure in rotating channel flows. In a numerical study of plane Couette flow rotating slowly about an axis aligned with the mean vorticity, Bech & Andersson (1996a) found that the turbulence level was damped in the presence of anticyclonic system rotation, in spite of the occurrence of longitudinal counter-rotating roll cells. Moreover, the turbulence anisotropy was practically unaffected by the weak rotation, for which the rotation number Ro, defined as the ratio of twice the imposed angular vorticity [Omega] to the shear rate of the corresponding laminar flow, was ±0.01. The aim of the present paper is to explore the effects of stronger anticyclonic system rotation on directly simulated turbulent plane Couette flow. Turbulence statistics like energy, enstrophy and Taylor lengthscales, both componental and directional, were computed from the statistically steady flow fields and supplemented by structural information obtained by conditional sampling.

  2. An efficient and inexpensive system for greenhouse pot rotation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large greenhouse experiments require frequent pot rotation to minimize the effects of variation in greenhouse climatic conditions. A manual rotation process is often cumbersome and labor intensive. To increase the efficiency of the rotation process, we propose an inexpensive, modular system fabricat...

  3. 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

  4. 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.

  5. Some current research in rotating-disc systems.

    PubMed

    Owen, J M; Wilson, M

    2001-05-01

    Rotating-disc systems are used to model the flow and heat transfer that occurs inside the cooling-air systems of gas-turbine engines. In this paper, recent computational and experimental research in three systems is discussed: rotor-stator systems, rotating cavities with superposed flow and buoyancy-induced flow in a rotating cavity. Discussion of the first two systems concentrates respectively on pre-swirl systems and rotating cavities with a peripheral inflow and outflow of cooling air. Buoyancy-induced flow in a rotating cavity is one of the most difficult problems facing computationalists and experimentalists, and there are similarities between the circulation in the Earth's atmosphere and the flow inside gas-turbine rotors. For this case, results are presented for heat transfer in sealed annuli and in rotating cavities with an axial throughflow of cooling air. PMID:11460629

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    Ron, Hagai; Nur, Amos; Aydin, Atilla

    1990-02-01

    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.

  8. 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.

  9. 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.

  10. 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.

  11. Numerical study of liquid phase diffusion growth of SiGe subjected to accelerated crucible rotation

    NASA Astrophysics Data System (ADS)

    Sekhon, M.; Lent, B.; Dost, S.

    2016-03-01

    The effect of accelerated crucible rotation technique (ACRT) on liquid phase diffusion (LPD) growth of SixGe1-x crystal has been investigated numerically. Transient, axisymmetric simulations have been carried out for triangular and trapezoidal ACRT cycles. Natural convection driven flow in the early growth hours is found to be modified by the ACRT induced Ekman flow. Results also reveal that a substantial mixing in the solution can be induced by the application of ACRT in the later hours of growth which is otherwise a diffusion dominated growth period for LPD growth technique. A comparison is drawn to the cases of stationary crucible and crucible rotating at a constant speed examined previously for this growth system by Sekhon and Dost (J. Cryst. Growth 430 (2015) 63). It is found that a superior interface flattening effect and radial compositional uniformity along the growth interface can be accomplished by employing ACRT at 12 rpm than that which could be achieved by using steady crucible rotation at 25 rpm, owing to the higher time averaged growth velocity achieved in the former case. Furthermore, minor differences are also predicted in the results obtained for trapezoidal and triangular ACRT cycles.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Phase-Measuring System

    NASA Technical Reports Server (NTRS)

    Davis, W. T.

    1986-01-01

    System developed and used at Langley Research Center measures phase between two signals of same frequency or between two signals, one of which is harmonic multiple of other. Simple and inexpensive device combines digital and analog components to give accurate phase measurements. One signal at frequency f fed to pulse shaper, produces negative pulse at time t4. Pulse applied to control input of sample-and-hold module 1. Second signal, at frequency nf, fed to zero-crossover amplifier, producing square wave at time t. Signal drives first one-shot producing narrow negative pulse at t1. Signal then drives second one-shot producing narrow positive pulse at time t2. This pulse used to turn on solid-state switch and reset integrator circuit to zero.

  18. 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.

  19. Note: A time-resolved Kerr rotation system with a rotatable in-plane magnetic field

    NASA Astrophysics Data System (ADS)

    Qian, Xuan; Gu, Xiaofang; Ji, Yang

    2010-10-01

    A time-resolved Kerr rotation system with a rotatable in-plane magnetic field has been constructed to study anisotropic spin relaxation of electrons in semiconductors. A permanent magnet magic ring is placed on top of a motor-driven rotation stage (RS) to create the rotatable in-plane magnetic field. The RS is placed on a second translation stage to vary the local magnetic field around a sample. The in-plane magnetic field in such a system varies from 0.05 to 0.95 T, with full-round 360° rotatablity, thus offering a convenient and low-cost way to study the anisotropy of spin dynamics in semiconductors. Its performance was demonstrated via measurement of the anisotropy of the spin dephasing time (SDT) of electrons in a two-dimensional electron system embedded in a GaAs/Al0.35Ga0.65As heterostructure. The SDT with B∥[11¯0] was observed to be 10% larger than that with B∥[110], consistent with the results of others, which was measured via rotating sample.

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. Cylindrical Cardboard Model for a Rotating System in Special Relativity.

    ERIC Educational Resources Information Center

    Noerdlinger, Peter D.

    1979-01-01

    Presents a cylindrical cardboard model that helps students at the graduate or undergraduate level to visualize the nature of simultaneity and the propagation of light in a rotating coordinate system. (HM)

  5. 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

  6. 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].…

  7. Rotational artifact in phase imaging of cardiac scans: potential pitfalls in diagnosis

    SciTech Connect

    Lee, V.W.; Getchell, J.; Foster, J.E.; Salzman, L.; Plehn, J.

    1987-10-01

    In the past few years, we have occasionally observed linear bands in the phase images of gated cardiac blood-pool scans along the interventricular septum region among patients with normal septal motions. Our retrospective study investigated the cause of out-of-phase bands of 12 patients. We documented through review of cines, computer analysis of gated cardiac blood-pool scintigraphy data, and correlation with echocardiograms that this phenomenon was artifact introduced by rotational movements of the heart. It is important for nuclear physicians to recognize this rotational artifact on the phase analysis image in order to avoid the erroneous misdiagnosis of wall motion abnormalities of the septum.

  8. 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.

  9. 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

  10. Instability and new phases of higher-dimensional rotating black holes

    SciTech Connect

    Dias, Oscar J. C.; Monteiro, Ricardo; Santos, Jorge E.; Figueras, Pau; Emparan, Roberto

    2009-12-01

    It has been conjectured that higher-dimensional rotating black holes become unstable at a sufficiently large value of the rotation, and that new black holes with pinched horizons appear at the threshold of the instability. We search numerically and find the stationary axisymmetric perturbations of Myers-Perry black holes with a single spin that mark the onset of the instability and the appearance of the new black hole phases. We also find new ultraspinning Gregory-Laflamme instabilities of rotating black strings and branes.

  11. 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.

  12. Icing research tunnel rotating bar calibration measurement system

    NASA Technical Reports Server (NTRS)

    Gibson, Theresa L.; Dearmon, John M.

    1993-01-01

    In order to measure icing patterns across a test section of the Icing Research Tunnel, an automated rotating bar measurement system was developed at the NASA Lewis Research Center. In comparison with the previously used manual measurement system, this system provides a number of improvements: increased accuracy and repeatability, increased number of data points, reduced tunnel operating time, and improved documentation. The automated system uses a linear variable differential transformer (LVDT) to measure ice accretion. This instrument is driven along the bar by means of an intelligent stepper motor which also controls data recording. This paper describes the rotating bar calibration measurement system.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Visual Servoed Three-Dimensional Cell Rotation System.

    PubMed

    Wang, Zenan; Latt, Win Tun; Tan, Steven Yih Min; Ang, Wei Tech

    2015-10-01

    Three-dimensional (3-D) positioning and orientation of embryos/oocytes is necessary to facilitate micromanipulation tasks such as cell injection and cellular structural biopsy commonly performed under a microscope. Conventional cell orientation is performed manually by using a vacuum equipped micropipette to aspirate and release the cell, which is a trial-and-error approach. The conventional method relies heavily on the skill of the operator; it also suffers from low precision, low success rate and low controllability. These drawbacks illustrate the need for a systematic 3-D cell rotational system to automate the cell orientation process. In this paper, we present a noninvasive single cell rotation system that can automatically orientate a zebrafish embryo to a desired position when both the cytoplasm and the yolk are in the focal plane. A three-point-contact model for cell rotation that involves a custom-designed rotational stage is introduced to provide precise rotational position control. A vision recognition algorithm is also proposed to enable the visual servoing function of the system. Experimental results show that the proposed system can achieve high success rates of 92.5% (x-axis rotation with 40 trails) and 97.5% (about the z-axis with 80 trails). The system can also successfully complete 3-D cell orientation at an average speed of 31 s/cell with a high in-plane rotation accuracy of 0.3 (°) . As a high precise, high controllable and deterministic cell manipulating system, it provides a starting point for automated cell manipulation for intracytoplasmic sperm injection and embryo biopsy for preimplantation genetic diagnosis. PMID:25993702

  19. 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.

  20. 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.

  1. On-the-shaft data systems for rotating engine components

    NASA Technical Reports Server (NTRS)

    Lesco, D. J.; Sturman, J. C.; Nieberding, W. C.

    1972-01-01

    Two rotating data systems for engine component testing which demonstrate the techniques of on-the-shaft microelectronic signal conditioning and rotary transformer power- and data-transfer are described. (1) A digital data system provides 69 channels of 1100 C maximum thermocouple data with less than 0.5 percent error from a turbine test rig rotating at speeds up to 9000 rpm. (2) An analog data system amplifies and transfers 72 channels of dynamic strain data with less than 5 percent error from a compressor rig at speeds above 14,000 rpm.

  2. 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.

  3. 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.

  4. The aerodynamic analysis of the gyroplane rotating-wing system

    NASA Technical Reports Server (NTRS)

    Wheatley, John B

    1934-01-01

    An aerodynamic analysis of the gyroplane rotating-wing system is presented herein. This system consists of a freely rotating rotor in which opposite blades are rigidly connected and allowed to rotate or feather freely about their span axis. Equations have been derived for the lift, the lift-drag ratio, the angle of attack, the feathering angles, and the rolling and pitching moments of a gyroplane rotor in terms of its basic parameters. Curves of lift-drag ratio against lift coefficient have been calculated for a typical case, showing the effect of varying the pitch angle, the solidarity, and the average blade-section drag coefficient. The analysis expresses satisfactorily the qualitative relations between the rotor characteristics and the rotor parameters. As disclosed by this investigation, the aerodynamic principles of the gyroplane are sound, and further research on this wing system is justified.

  5. Superconducting magnets for induction linac phase rotation in a neutrino factory

    NASA Astrophysics Data System (ADS)

    Green, M. A.; Yu, S.

    2002-05-01

    The neutrino factory [1-3] consists of a target section where pions are produced and captured in a solenoidal magnetic field. Pions in a range of energies from 100 Mev to 400 MeV decay into muons in an 18-meter long channel of 1.25 T superconducting solenoids. The warm bore diameter of these solenoids is about 600 mm. The phase rotation section slows down the high-energy muon and speeds up the low energy muons to an average momentum of 200 MeV/c. The phase-rotation channel consists of three induction linac channels with a short cooling section and a magnetic flux reversal section between the first and second induction linacs and a drift space between the second and third induction linacs. The length of the phase rotation channel will be about 320 meters. The superconducting coils in the channel are 0.36 m long with a gap of 0.14 m between the coils. The magnetic induction within the channel will be 1.25 T. For 260 meters of the 320-meter long channel, the solenoids are inside the induction linac. This paper discusses the design parameters for the superconducting solenoids in the neutrino factory phase-rotation channel.

  6. 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.

  7. 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. PMID:25925318

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

    PubMed Central

    Peters, Ryan M.; Rasman, Brandon G.; Inglis, J. Timothy

    2015-01-01

    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. PMID:25925318

  9. Rotational hydrodynamic diffusion system to study mass transport across boundaries.

    PubMed

    Mamidi, Sai Sree; Meas, Bo; Farhat, Tarek R

    2008-11-01

    The design and operation of a new mass transport technique is presented. Rotational hydrodynamic diffusion system (RHDS) is a method that can be adapted for analytical laboratory analysis as well as industrial-scale separation and purification. Although RHDS is not an electrochemical technique, its concept is derived from hydrodynamic rotating disk electrode voltammetry. A diffusion advantage gained using the RHDS is higher flux of probe molecules across the boundary (e.g., membrane or porous media) with increased rotation rate compared to the static two-half-cell (THC) method. The separation concept of RHDS differs from pressurized, agitated, electrodialysis, and reversed osmosis systems in design and theory. The detection mechanism of the RHDS opens the possibility to study mass transport properties of a large variety of molecules using different types of ultrathin membranes. Therefore, the RHDS is a potential alternative to classical mass transport detection methods such as THC, impedance spectroscopy, and cyclic and rotating disk electrode voltammetry. Theoretical analysis on the rotational hydrodynamic flux is derived and compared to experimental flux measured using HCl, KCl, KNO 3, Ni(NO 3) 2, LiCl, camphor sulfonic acid, and K 3Fe(CN) 6 ionic solutions. Values of effective diffusion coefficients of salts across Nucleopore membranes of thickness 6.0 and 10 mum with pore size 0.1 and 0.2 mum, respectively, are presented and discussed. PMID:18844370

  10. Fibre Optic System for Monitoring Rotational Seismic Phenomena

    PubMed Central

    Kurzych, Anna; Jaroszewicz, Leszek R.; Krajewski, Zbigniew; Teisseyre, Krzysztof P.; Kowalski, Jerzy K.

    2014-01-01

    We outline the development and the application in a field test of the Autonomous Fibre-Optic Rotational Seismograph (AFORS), which utilizes the Sagnac effect for a direct measurement of the seismic-origin rotations of the ground. The main advantage of AFORS is its complete insensitivity to linear motions, as well as a direct measurement of rotational components emitted during seismic events. The presented system contains a special autonomous signal processing unit which optimizes its operation for the measurement of rotation motions, whereas the applied telemetric system based on the Internet allows for an AFORS remote control. The laboratory investigation of such two devices indicated that they keep an accuracy of no less than 5.1 × 10−9 to 5.5 × 10−8 rad/s in the detection frequency band from 0.83∼106.15 Hz and protect linear changes of sensitivity in the above bandpass. Some experimental results of an AFORS-1 application for a continuous monitoring of the rotational events in the Książ (Poland) seismological observatory are also presented. PMID:24651723

  11. Fibre optic system for monitoring rotational seismic phenomena.

    PubMed

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

    2014-01-01

    We outline the development and the application in a field test of the Autonomous Fibre-Optic Rotational Seismograph (AFORS), which utilizes the Sagnac effect for a direct measurement of the seismic-origin rotations of the ground. The main advantage of AFORS is its complete insensitivity to linear motions, as well as a direct measurement of rotational components emitted during seismic events. The presented system contains a special autonomous signal processing unit which optimizes its operation for the measurement of rotation motions, whereas the applied telemetric system based on the Internet allows for an AFORS remote control. The laboratory investigation of such two devices indicated that they keep an accuracy of no less than 5.1 × 10(-9) to 5.5 × 10(-8) rad/s in the detection frequency band from 0.83~106.15 Hz and protect linear changes of sensitivity in the above bandpass. Some experimental results of an AFORS-1 application for a continuous monitoring of the rotational events in the Książ (Poland) seismological observatory are also presented. PMID:24651723

  12. 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

  13. Correlated Rotational Noise in Active Brownian Systems

    NASA Astrophysics Data System (ADS)

    Wagner, Caleb; Baskaran, Aparna

    We consider a system of self-propelled particles in a viscous medium for which the angle parametrizing the direction of particle propulsion is subject to correlated noise. The physics involved in the correlated noise is explored by deriving a modified Smoluchowski equation that governs the evolution of the probability distribution for particle positions and orientations. More precisely, given noise correlations that decay exponentially in time with decay constant ν, we give the modified Smoluchowski equation as a perturbative expansion in ν. While the physical origins of correlated noise may be diverse, we give one interpretation of the resulting dynamics in terms of inertial effects that are absent from the usual overdamped description of self-propelled particles in a viscous medium.

  14. 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…

  15. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    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.

  17. Rotational motion of traveling spots in dissipative systems.

    PubMed

    Teramoto, Takashi; Suzuki, Katsuya; Nishiura, Yasumasa

    2009-10-01

    What is the origin of rotational motion? An answer is presented through the study of the dynamics for spatially localized spots near codimension 2 singularity consisting of drift and peanut instabilities. The drift instability causes a head-tail asymmetry in spot shape, and the peanut one implies a deformation from circular to peanut shape. Rotational motion of spots can be produced by combining these instabilities in a class of three-component reaction-diffusion systems. Partial differential equations dynamics can be reduced to a finite-dimensional one by projecting it to slow modes. Such a reduction clarifies the bifurcational origin of rotational motion of traveling spots in two dimensions in close analogy to the normal form of 1:2 mode interactions. PMID:19905416

  18. 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.

  19. Rotational tunneling of methyl groups in low temperature phases of mesitylene: potentials and structural implications.

    PubMed

    Prager, M; Grimm, H; Natkaniec, I

    2005-07-01

    Mesitylene can be stabilized at He temperature in three solid phases of so far unknown crystal structures. Rotational tunneling of methyl groups is based on rotational potentials and used to characterize structural aspects. In phase III found after the first fast cooling of the sample three nonequivalent methyl rotors with splittings of 2.7, 4.1 and 16.3 microeV are observed. Three other unresolved bands are identified by their librational modes. In the second phase II the metastability is emphasized by tunneling energies still changing at temperatures T< or = 12 K. Above this temperature tunneling bands at 6.6, 12.5, 15.0 and 18.3 microeV evolve in the manner characteristic of coupling to phonons. In the equilibrium phase I a single tunnel splitting of 10.2 microeV represents all methyl groups. A unit cell containing a single molecule at a site of threefold symmetry explains quantitatively this spectrum. Phases II and III most likely contain two nonequivalent molecules in the unit cell with no local symmetry in phase II and a mirror plane in phase III. The good moderator properties for neutrons are most likely not connected to the low energy tunneling bands but to a dense vibrational phonon density of states. PMID:16189568

  20. 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.

  1. Hadronic matter phases and their application to rapidly rotating neutron stars

    NASA Astrophysics Data System (ADS)

    Endo, Tomoki

    2016-05-01

    Neutron stars are commonly considered as astronomical objects having high-density interiors and an inner core region in which various hadronic matter phases are expected. Several studies show that the inner structures affect macroscopic phenomena of the star. However, we know that the inner structures of the star strongly depend on the equation of state (EOS). The EOS of high-density matter is still not clear and several recent observations indicate restrictions to EOSs. Theoretical studies should elucidate EOSs at high density and/or high temperature. For instance, many theoretical studies have attempted to account for the rotation effect of rapidly rotating neutron stars (i.e., pulsars). Accordingly, we also apply our EOSs to rapidly rotating stars. Furthermore, neutron stars generate a strong magnetic field. Several recent studies indicate that this magnetic field exerts restrictions on the EOS. In this paper, we focus on the investigation of the inner structures and the application of our EOSs to rotating stars. We find that one of our EOSs is consistent with observations, and another is inconsistent. We also find an important relation between the radius and rotation.

  2. 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.

  3. 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.

  4. Phase transition in the two-dimensional dipolar planar rotator model

    NASA Astrophysics Data System (ADS)

    Mól, L. A. S.; Costa, B. V.

    2010-02-01

    In this work we have used extensive Monte Carlo simulations and finite size scaling theory to study the phase transition in the dipolar planar rotator model (dPRM), also known as dipolar XY model. The true long-range character of the dipolar interactions was taken into account by using the Ewald summation technique. Our results for the critical exponents do not fit those from known universality classes. We observed that the specific heat is apparently non-divergent and the critical exponents are ν = 1.277(2), β = 0.2065(4) and γ = 2.218(5). The critical temperature was found to be Tc = 1.201(1). Our results are clearly distinct from those of a recent renormalization group study from Maier and Schwabl (2004 Phys. Rev. B 70 134430) and agrees with the results from a previous study of the anisotropic Heisenberg model with dipolar interactions in a bilayer system using a cut-off in the dipolar interactions (Mól and Costa 2009 Phys. Rev. B 79 054404).

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

    PubMed Central

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

    2014-01-01

    We describe a method for differential phase measurement of Faraday rotation from multiple depth locations simultaneously. A polarization-maintaining fiber-based spectral-domain interferometer which 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 multi-surface sample. System sensitivity for the Faraday rotation measurement is 0.86 minutes of arc. Verdet constants of clear liquids and turbid media are measured at 687 nm. PMID:24217734

  6. 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

  7. DESIGN NOTE: Phase meter for a rotating grating goniometer using a personal computer and sound card

    NASA Astrophysics Data System (ADS)

    Tan, S. M.; Watkins, L. R.

    2005-07-01

    A sound card and personal computer are used to implement a digital phase meter for a rotating grating goniometer. Inexpensive reflective optical sensors read the goniometer grating and produce sinusoidal waveforms which are continuously acquired and digitized by a personal computer sound card. Digital signal processing algorithms calculate the time-averaged relative phase of these waveforms, enabling the angle between the reference head and moving head to be determined in real time. Comparison with a calibration grade polygon yielded an experimentally measured error of 9 arcsec or better over an angular range of 90°.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Axial super-localisation using rotating point spread functions shaped by polarisation-dependent phase modulation.

    PubMed

    Roider, Clemens; Jesacher, Alexander; Bernet, Stefan; Ritsch-Marte, Monika

    2014-02-24

    We present an approach for point spread function (PSF) engineering that allows one to shape the optical wavefront independently in both polarisation directions, with two adjacent phase masks displayed on a single liquid-crystal spatial light modulator (LC-SLM). The set-up employs a polarising beam splitter and a geometric image rotator to rectify and process both polarisation directions detected by the camera. We shape a single-lobe ("corkscrew") PSF that rotates upon defocus for each polarisation channel and combine the two polarisation channels with a relative 180° phase-shift on the computer, merging them into a single PSF that exhibits two lobes whose orientation contains information about the axial position. A major advantage lies in the possibility to measure and eliminate the aberrations in the two polarisation channels independently. We demonstrate axial super-localisation of isotropically emitting fluorescent nanoparticles. Our implementation of the single-lobe PSFs follows the method proposed by Prasad [Opt. Lett.38, 585 (2013)], and thus is to the best of our knowledge the first experimental realisation of this suggestion. For comparison we also study an approach with a rotating double-helix PSFs (in only one polarisation channel) and ascertain the trade-off between localisation precision and axial working range. PMID:24663724

  14. On linear structure and phase rotation invariant properties of block M-PSK modulation codes

    NASA Technical Reports Server (NTRS)

    Kasami, Tadao; Takata, Toyoo; Fujiwara, Toru; Lin, Shu

    1991-01-01

    Two important structural properties of block M(=2')-ary PSK modulation codes, linear structure and phase symmetry, are investigated. An M-ary modulation code is first represented as a code with symbols from the integer group S(MPSK) = (0,1,2,...M-1) under modulo-M addition. Then the linear structure of block MPSK modulation codes over S(M-PSK) with respect to modulo-M vector addition is defined, and conditions are derived under which a block MPSK modulation code is linear. Once the linear structure is developed, the phase symmetry of block M-PSK modulation codes is studied. In particular, a necessary and sufficient condition for a block MPSK modulation code that is linear as a binary code to be invariant under 2 h 180 deg/M phase rotation (for h = 1 to l) is derived. Finally, a list of short 8PSK and 16PSK modulation codes is given, together with their linear structure and the smallest phase rotation for which a code is invariant.

  15. 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.

  16. Dependence of Berry's phase for atom on a sign of the g factor in the rotating magnetic field

    SciTech Connect

    Morinaga, Atsuo; Aoki, Takatoshi; Yasuhara, Makoto

    2005-05-15

    Berry's phase of the atom in the state with a positive or negative g factor for partial cycles of a rotating magnetic field was determined free from the dynamical phase shift using a time-domain atom interferometer. The experimental phase shift is in good agreement with the prediction of Berry's phase for partial cycles. It was found that the sense of Berry's phase depends on the sign of the magnetic quantum number, the sense of the rotating magnetic field, and the sign of the g factor of the state.

  17. 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.

  18. Longitudinal Wakefield Study in SLAC Rotatable Collimator Design for the LHC Phase II Upgrade

    SciTech Connect

    Xiao, Liling; Lundgren, Steven; Markiewicz, Thomas; Ng, Cho-Kuen; Smith, Jeffrey; /SLAC

    2010-08-25

    SLAC proposed a rotatable collimator design for the LHC Phase II collimation upgrade. There are 20 facet faces on each cylindrical jaw surface and two jaws are rotatable in order to introduce a clean surface in case of a beam hitting a jaw during operation. When the beam crosses the collimator, it will excite broad-band and narrow-band modes. The longitudinal modes can contribute to beam energy loss and power dissipation on the vacuum chamber wall. In this paper, the parallel finite element eigensolver Omega3P is used to search for all the longitudinal trapped modes in the SLAC collimator design. The power dissipation generated by the beam in collimators with different vacuum chamber and RF contact designs is discussed. It is found that a wider RF foil connecting the jaw and the vacuum flange can reduce efficiently the beam heating caused by the longitudinal modes.

  19. Laser scanning system for 360-deg. rotation object surface morphology

    NASA Astrophysics Data System (ADS)

    Yang, Juan; Tu, DaWei

    2004-01-01

    A non-contact morphology system for 360° object surface measurement, involving a CCD camera, a line-structured light source and a rotated platform has been developed based on the triangulation method. The system parameters have been optimized to meet the requirement of system specification, such as range scope, range resolution, measurement accuracy and the shadow effect. For sampling the whole object surface, the CCD camera captures one frame after the motor rotates every step of 1.5° under the control of a computer. The mapping relationship among the 2-D images and 3-D surfaces from the different views and orientations can be developed by means of the spatial geometric correspondence. Moreover, the intensity, color and texture information from the CCD intensity image can be affixed to the entire 3-D surface with OpenGL. The system records more than 160000 facial coordinates with a dynamic resolution of approximately 1 mm in 60s. Examples of application of the system are given.

  20. Construction of models of rotating stars and stellar systems

    SciTech Connect

    Vandervoort, P.O.; Welty, D.E.

    1981-09-01

    A new method is presented for the construction of the equilibrium configurations of rotating stars and stellar systems. A configuration is represented in a first approximation as stratified on similar and similarly situated ellipsoids. The stratification is determined by solving a spherically symmetric model of the governing equations, whereas the ellipsoidal geometry is determined by solving the tensor virial equations of the second order. The structure of the configuration is determined in a second approximation by solving exactly the equations of mechanical equilibrium in which the prevailing gravitational field is given by the solution for the field obtained in the first approximation. The method is formulated in detail for barotropic configurations and applied to the construction of both axisymmetric and nonaxisymmetric configurations of uniformly rotating polytropes. Comparisons of the present results with results obtained in other investigations with the aid of purely numerical methods show that the new method described here gives a surprisingly accurate representation of the structures of uniformly rotating polytropes. Generalizations and wider applications of the method are briefly described.

  1. Reconstructing very short TE phase rotation spectral data collected with multichannel phased-array coils at 3 T.

    PubMed

    Wijtenburg, S Andrea; Knight-Scott, Jack

    2011-09-01

    Phased-array volume coils were used in conjunction with the phase rotation STEAM (PR-STEAM) spectroscopy technique to acquire very short TE data from the anterior cingulate gyrus at 3 T. A method for combining PR-STEAM data from multiple subcoils is presented. The data were acquired from seven healthy participants using PR-STEAM (repetition time/mixing time/echo time=3500/10/6.5 ms, 6 cm(3), NEX=128, spectral width=2000 Hz, 2048 complex points, Δφ(1)=135°, Δφ(2)=22.5°, Δφ(3)=112.5° and Δφ(ADC)=0°). In addition to the primary metabolites, LCModel fit results suggest that glutathione and glutamate can also be identified with Cramér-Rao lower bounds of 10% or less. PMID:21550744

  2. Symmetry-protected topological phases in noninteracting fermion systems

    NASA Astrophysics Data System (ADS)

    Wen, Xiao-Gang

    2012-02-01

    Symmetry-protected topological (SPT) phases are gapped quantum phases with a certain symmetry, which can all be smoothly connected to the same trivial product state if we break the symmetry. For noninteracting fermion systems with time reversal (T̂), charge conjugation (Ĉ), and/or U(1) (N̂) symmetries, the total symmetry group can depend on the relations between those symmetry operations, such as T̂N̂T̂-1=N̂ or T̂N̂T̂-1=-N̂. As a result, the SPT phases of those fermion systems with different symmetry groups have different classifications. In this paper, we use Kitaev's K-theory approach to classify the gapped free-fermion phases for those possible symmetry groups. In particular, we can view the U(1) as a spin rotation. We find that superconductors with the Sz spin-rotation symmetry are classified by Z in even dimensions, while superconductors with the time reversal plus the Sz spin-rotation symmetries are classified by Z in odd dimensions. We show that all 10 classes of gapped free-fermion phases can be realized by electron systems with certain symmetries. We also point out that, to properly describe the symmetry of a fermionic system, we need to specify its full symmetry group that includes the fermion number parity transformation (-)N̂. The full symmetry group is actually a projective symmetry group.

  3. An optimized rotating helium-recondensing system using Roebuck refrigerators

    NASA Astrophysics Data System (ADS)

    Jeong, Sangkw. O. O. N.; Lee, C.

    1999-09-01

    This paper describes an optimized design of the helium-recondensing system utilizing cascade Roebuck refrigerators. A superconducting generator or motor has a superconducting field winding in its rotor that should be continuously cooled by cryogen. Liquid helium transfer from the stationary system to the rotor of the LTS (Low Temperature Superconductor) superconducting generator has been problematic, cumbersome, and inefficient. The novel concept of a rotating helium-recondensing system is contrived. The vaporized cold helium inside the rotor is isothermally compressed by centrifugal force and recondensed to 4.2 K reservoir through the expansion process. There is no helium coupling between the rotor and the stationary liquid helium storage. Thermodynamic analysis of the cascade refrigeration system is performed to determine the optimum key design parameters. The loss mechanisms are also described to point out the sources that might reduce the system performance.

  4. 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

  5. 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.

  6. 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

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

    PubMed

    Holly, Jan E; 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 degrees /s) and fast (180 degrees /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

  8. 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.

  9. 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.

  10. Phase transitions in disordered systems

    NASA Astrophysics Data System (ADS)

    Hrahsheh, Fawaz Y.

    Disorder can have a wide variety of consequences for the physics of phase transitions. Some transitions remain unchanged in the presence of disorder while others are completely destroyed. In this thesis we study the effects of disorder on several classical and quantum phase transitions in condensed matter systems. After a brief introduction, we study the ferromagnetic phase transition in a randomly layered Heisenberg magnet using large-scale Monte-Carlo simulations. Our results provide numerical evidence for the exotic infinite-randomness scenario. We study classical and quantum smeared phase transitions in substitutional alloys A1-xBx. Our results show that the disorder completely destroys the phase transition with a pronounced tail of the ordered phase developing for all compositions x < 1. In addition, we find that short-ranged disorder correlations can have a dramatic effect on the transition. Moreover, we show an experimental realization of the composition-tuned ferromagnetic-to-paramagnetic quantum phase transition in Sr1-xCa xRuO3. We investigate the effects of disorder on first-order quantum phase transitions on the example of the N-color quantum Ashkin-Teller model. By means of a strong disorder renormalization group, we demonstrate that disorder rounds the first-order transition to a continuous one for both weak and strong coupling between the colors. Finally, we investigate the superfluid-insulator quantum phase transition of one-dimensional bosons with off-diagonal disorder by means of large-scale Monte-Carlo simulations. Beyond a critical disorder strength, we find nonuniversal, disorder dependent critical behavior.

  11. 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

  12. Optically controlled microwave phase shifter based on nonlinear polarization rotation in a highly nonlinear fiber.

    PubMed

    Li, Wei; Sun, Wen Hui; Wang, Wen Ting; Zhu, Ning Hua

    2014-06-01

    This Letter reports an optically controlled microwave phase shifter with an ultra-wideband working bandwidth and a full 360° phase shifting range based on nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNLF). A continuous wave probe light is modulated by a polarization modulator (PolM) that is driven by a microwave signal to be phase shifted. The optical carrier and the first-order sidebands of the probe light experience different phase shifts due to the NPR induced by the control light in the HNLF. An optical bandpass filter is used to realize single-sideband modulation of the probe light by removing one of the first-order sidebands, as well as to reject the control light. After detecting by a photodetector, the phase of the recovered microwave signal is continuously tunable by adjusting the power of the control light. The proposed approach is theoretically analyzed and experimentally verified. A full 360° tunable phase shift is realized over an ultra-wideband frequency range from 8 to 38 GHz when the power of the control light is tuned from 0 to 570 mW. PMID:24876035

  13. Dynamics of Rotating Multi-component Turbomachinery Systems

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles

    1993-01-01

    The ultimate objective of turbomachinery vibration analysis is to predict both the overall, as well as component dynamic response. To accomplish this objective requires complete engine structural models, including multistages of bladed disk assemblies, flexible rotor shafts and bearings, and engine support structures and casings. In the present approach each component is analyzed as a separate structure and boundary information is exchanged at the inter-component connections. The advantage of this tactic is that even though readily available detailed component models are utilized, accurate and comprehensive system response information may be obtained. Sample problems, which include a fixed base rotating blade and a blade on a flexible rotor, are presented.

  14. 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. PMID:24161650

  15. The oblate spheroidal harmonics under coordinate system rotation and translation

    NASA Astrophysics Data System (ADS)

    Panou, Georgios

    2014-05-01

    Several recent studies in geodesy and related sciences make use of oblate spheroidal harmonics. For instance, the Earth's external gravitational potential can be mathematically expanded in an oblate spheroidal harmonic series which converges outside any spheroid enclosing all the masses. In this presentation, we develop the exact relations between the solid oblate spheroidal harmonics in two coordinate systems, related to each other by an arbitrary rotation or translation. We start with the relations which exist between the spherical harmonics in the two coordinate systems. This problem has received considerable attention in the past and equivalent results have been independently derived by several investigators. Then, combining the previous results with the expressions which relate the solid spherical harmonics and the solid spheroidal harmonics, we obtain the relations under consideration. For simplicity, complex notation has been adopted throughout the work. This approach is also suitable and easy to use in the zonal harmonic expansions. The spherical harmonics under coordinate system rotation and translation are obtained as a degenerate case. The above theory can be used in any spheroidal harmonic model. Finally, some simple examples are given, in order to illuminate the mathematical derivations.

  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. Universal quantum gates for atomic systems assisted by Faraday rotation

    NASA Astrophysics Data System (ADS)

    Song, Guo-Zhu; Zhang, Mei

    2015-08-01

    Both cavity quantum electrodynamics and photons are promising candidates for quantum information processing. Here we present two efficient schemes for universal quantum gates, that is, Fredkin gates and \\sqrt{\\text{SWAP}} gates on atomic systems, assisted by Faraday rotation catalyzed by an auxiliary single photon. These gates are achieved by successfully reflecting an auxiliary single photon from an optical cavity with a single-trapped atom. They do not require additional qubits and they only need some linear-optical elements besides the nonlinear interaction between the flying photon and the atoms in the optical cavities. Moreover, these two universal quantum gates are robust. A high fidelity can be achieved in our schemes with current experimental technology. They may be very useful in quantum information processing in future, with the great progress on controlling atomic systems.

  18. Rotational deformities of the long bones can be corrected with rotationally guided growth during the growth phase.

    PubMed

    Cobanoglu, Mutlu; Cullu, Emre; Kilimci, Figen Sevil; Ocal, Mehmet Kamil; Yaygingul, Rahime

    2016-06-01

    Background and purpose - Coronal and sagittal plane long bone deformities can be corrected with guided growth, whereas transverse plane rotational deformities require osteotomy and internal or external fixation. We investigated whether rotational changes can be introduced with the plating technique. Methods - 45 rabbits (6 weeks old) were divided into 3 groups. The unoperated right tibia was used as control. In groups 1 and 3, two plates were placed obliquely to the long axis and in different directions. In group 2, a sham operation was performed with screws. Animals in groups 1 and 2 were followed for 4 weeks. In group 3 the implants were removed 4 weeks after the operation to observe rebound effect, and the animals were followed for another 4 weeks. The tibial torsion was assessed on computed tomography (CT). External rotation was accepted as a negative value. Results - In group 1, mean torsion was -20° (SD 7.9) in the right tibia and -2.9° (SD 7.2) in the left tibia (p < 0.001). In group 2, mean torsion was -23° (SD 4.9) in the right tibia and -26° (SD 6.5) in the left tibia (p = 0.2). In group 3, mean torsion was -21° (SD 6.3) in the right tibia and -9.5° (SD 5.3) in the left tibia (p < 0.001). Intergroup evaluation for left torsion showed a significant difference between group 2 and the other groups (p < 0.001). When the rebound effect was evaluated, there was no statistically significant difference between groups 1 and 3 (p = 0.08). Interpretation - A rotational change was attained with this technique. Although a rebound effect was seen after implant removal, it did not reach statistical significance. The final rotational change remained constant. PMID:26900795

  19. Rotational deformities of the long bones can be corrected with rotationally guided growth during the growth phase

    PubMed Central

    Cobanoglu, Mutlu; Cullu, Emre; Kilimci, Figen Sevil; Ocal, Mehmet Kamil; Yaygingul, Rahime

    2016-01-01

    Background and purpose Coronal and sagittal plane long bone deformities can be corrected with guided growth, whereas transverse plane rotational deformities require osteotomy and internal or external fixation. We investigated whether rotational changes can be introduced with the plating technique. Methods 45 rabbits (6 weeks old) were divided into 3 groups. The unoperated right tibia was used as control. In groups 1 and 3, two plates were placed obliquely to the long axis and in different directions. In group 2, a sham operation was performed with screws. Animals in groups 1 and 2 were followed for 4 weeks. In group 3 the implants were removed 4 weeks after the operation to observe rebound effect, and the animals were followed for another 4 weeks. The tibial torsion was assessed on computed tomography (CT). External rotation was accepted as a negative value. Results In group 1, mean torsion was −20° (SD 7.9) in the right tibia and −2.9° (SD 7.2) in the left tibia (p < 0.001). In group 2, mean torsion was −23° (SD 4.9) in the right tibia and −26° (SD 6.5) in the left tibia (p = 0.2). In group 3, mean torsion was −21° (SD 6.3) in the right tibia and −9.5° (SD 5.3) in the left tibia (p < 0.001). Intergroup evaluation for left torsion showed a significant difference between group 2 and the other groups (p < 0.001). When the rebound effect was evaluated, there was no statistically significant difference between groups 1 and 3 (p = 0.08). Interpretation A rotational change was attained with this technique. Although a rebound effect was seen after implant removal, it did not reach statistical significance. The final rotational change remained constant. PMID:26900795

  20. Ultramicrowave communications system, phase 2

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Communications system design was completed and reviewed. Minor changes were made in order to make it more cost effective and to increase design flexibility. System design activities identified the techniques and procedures to generate and monitor high data rate test signals. Differential bi-phase demodulation is the proposed method for this system. The mockup and packaging designs were performed, and component layout and interconnection constraints were determined, as well as design drawings for dummy parts of the system. The possibility of adding a low cost option to the transceiver system was studied. The communications program has the advantage that new technology signal processing devices can be readily interfaced with the existing radio frequency subsystem to produce a short range radar.

  1. Rotation of stress and blocks in the Lake Mead, Nevada, Fault System

    NASA Astrophysics Data System (ADS)

    Ron, Hagai; Nur, Amos; Aydin, Atilla

    1993-08-01

    The combined effects of stress field rotation and material rotation were found in the Lake Mead, Nevada Fault System (LMFS). Fault inversion results imply an apparent 60 deg clockwise (CW) rotation of the stress field since mid-Miocene time. In contrast, structural data from the Great Basin suggest only a 30 deg CW stress field rotation. By incorporating paleomagnetic declination anomalies, it is inferred that slip on faults caused a local 30 deg counterclockwise rotation of blocks and faults in the Lake Mead area, so that the inferred 60 deg CW rotation of the stress field in the LMFS is actually only 30 deg.

  2. 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.

  3. 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.

  4. 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.

  5. Ageostrophic instabilities in a two fluid system with rotation

    NASA Technical Reports Server (NTRS)

    Ramanathan, N.; Rao, D. B.

    1984-01-01

    The stability of synoptic scale waves formed on a frontal surface is studied including nongeostrophic effects with the basic flow subjected to both vertical and horizontal shear. Spectral method is used to obtain the desired solutions. The stability characteristics of the developed unstable modes are presented as a function of shears of the basic flow. With the inclusion of barotropic shear the spectrum of instabilities increase. The lower speeded member of the mixed mode (gravitational-rotational) pair is influenced by the barotropic shear in the basic current and it appears at lower vertical shears. The structure of the height perturbations are utilized to distinguish the various unstable modes developed in the system together with their stability characteristics. This investigation has shown that the ageostrophic effects can be a significant factor in the development of synoptic scale waves on a frontal surface.

  6. Beyond the diffraction limit of optical/IR interferometers. I. Angular diameter and rotation parameters of Achernar from differential phases

    NASA Astrophysics Data System (ADS)

    Domiciano de Souza, A.; Hadjara, M.; Vakili, F.; Bendjoya, P.; Millour, F.; Abe, L.; Carciofi, A. C.; Faes, D. M.; Kervella, P.; Lagarde, S.; Marconi, A.; Monin, J.-L.; Niccolini, G.; Petrov, R. G.; Weigelt, G.

    2012-09-01

    Context. Spectrally resolved long-baseline optical/IR interferometry of rotating stars opens perspectives to investigate their fundamental parameters and the physical mechanisms that govern their interior, photosphere, and circumstellar envelope structures. Aims: Based on the signatures of stellar rotation on observed interferometric wavelength-differential phases, we aim to measure angular diameters, rotation velocities, and orientation of stellar rotation axes. Methods: We used the AMBER focal instrument at ESO-VLTI in its high-spectral resolution mode to record interferometric data on the fast rotator Achernar. Differential phases centered on the hydrogen Br γ line (K band) were obtained during four almost consecutive nights with a continuous Earth-rotation synthesis during ~5 h/night, corresponding to ~60° position angle coverage per baseline. These observations were interpreted with our numerical code dedicated to long-baseline interferometry of rotating stars. Results: By fitting our model to Achernar's differential phases from AMBER, we could measure its equatorial radius Req = 11.6 ± 0.3 R⊙, equatorial rotation velocity Veq = 298 ± 9 km s-1, rotation axis inclination angle i = 101.5 ± 5.2°, and rotation axis position angle (from North to East) PArot = 34.9 ± 1.6°. From these parameters and the stellar distance, the equatorial angular diameter ⌀eq of Achernar is found to be 2.45 ± 0.09 mas, which is compatible with previous values derived from the commonly used visibility amplitude. In particular, ⌀eq and PArot measured in this work with VLTI/AMBER are compatible with the values previously obtained with VLTI/VINCI. Conclusions: The present paper, based on real data, demonstrates the super-resolution potential of differential interferometry for measuring sizes, rotation velocities, and orientation of rotating stars in cases where visibility amplitudes are unavailable and/or when the star is partially or poorly resolved. In particular, we showed

  7. Flow and heat transfer in rotating-disc systems. Volume I - Rotor-stator systems

    NASA Astrophysics Data System (ADS)

    Owen, J. M.; Roger, R. H.

    The rotating flows occurring inside turbomachinery are discussed. Laminar and turbulent flow over a single disk and heat transfer from a single disk are addressed. Rotor-stator systems with and without superposed flow, heat transfer in rotor-stator systems, and the ingress problem of sealing rotor-stator systems are examined.

  8. [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

  9. 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.

  10. 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.

  11. Occultations by 81 Terpsichore and 694 Ekard in 2009 at Different Rotational Phase Angles

    NASA Astrophysics Data System (ADS)

    Timerson, Brad; Durech, J.; Pilcher, F.; Albers, J.; Beard, T.; Berger, B.; Berman, B.; Breit, D.; Case, T.; Collier, D.; Dantowitz, R.; Davies, T.; Desmarais, V.; Dunham, D.; Dunham, J.; Garlitz, J.; Garrett, L.; George, T.; Hill, M.; Hughes, Z.; Jacobson, G.; Kozubal, M.; Liu, Y.; Maley, P.; Morgan, W.; Morris, P.; Mroz, G.; Pool, S.; Preston, S.; Shelton, R.; Welch, S.; Westfall, J.; Whitman, A.; Wiggins, P.

    2010-10-01

    During 2009, IOTA observers in North America reported about 250 positive observations for 94 asteroidal occultation events. For two asteroids this included observations of multiple chords on two different dates which allowed well-defined profiles to be obtained at different rotational phase angles. Occultations by 81 Terpsichore on 2009 November 19 and 2009 December 25 yielded best-fit ellipses of 134.0 x 108.9 km and 123.6 x 112.2 km, respectively. Observations of 694 Ekard on 2009 September 23 and 2009 November 8 yielded fitted ellipses of 124.9 x 88.0 km and 88.5 x 104.0 km, respectively.

  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. 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.

  14. Nonequilibrium inhomogeneous steady state distribution in disordered, mean-field rotator systems

    NASA Astrophysics Data System (ADS)

    Campa, Alessandro; Gupta, Shamik; Ruffo, Stefano

    2015-05-01

    We present a novel method to compute the phase space distribution in the nonequilibrium stationary state of a wide class of mean-field systems involving rotators subject to quenched disordered external drive and dissipation. The method involves a series expansion of the stationary distribution in inverse of the damping coefficient; the expansion coefficients satisfy recursion relations whose solution requires computing a matrix where about three quarters of the elements vanish, making numerical evaluation simple and efficient. We illustrate our method for the paradigmatic Kuramoto model of spontaneous collective synchronization and for its two mode generalization, in the presence of noise and inertia, and demonstrate an excellent agreement between simulations and theory for the phase space distribution.

  15. Phase control system concepts and simulations

    SciTech Connect

    Lindsay, V.C.

    1980-07-01

    A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Mineev, V. P.

    2016-04-01

    The polar phase of superfluid ^3 He 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.

  18. EEMD Independent Extraction for Mixing Features of Rotating Machinery Reconstructed in Phase Space

    PubMed Central

    Ma, Zaichao; Wen, Guangrui; Jiang, Cheng

    2015-01-01

    Empirical Mode Decomposition (EMD), due to its adaptive decomposition property for the non-linear and non-stationary signals, has been widely used in vibration analyses for rotating machinery. However, EMD suffers from mode mixing, which is difficult to extract features independently. Although the improved EMD, well known as the ensemble EMD (EEMD), has been proposed, mode mixing is alleviated only to a certain degree. Moreover, EEMD needs to determine the amplitude of added noise. In this paper, we propose Phase Space Ensemble Empirical Mode Decomposition (PSEEMD) integrating Phase Space Reconstruction (PSR) and Manifold Learning (ML) for modifying EEMD. We also provide the principle and detailed procedure of PSEEMD, and the analyses on a simulation signal and an actual vibration signal derived from a rubbing rotor are performed. The results show that PSEEMD is more efficient and convenient than EEMD in extracting the mixing features from the investigated signal and in optimizing the amplitude of the necessary added noise. Additionally PSEEMD can extract the weak features interfered with a certain amount of noise. PMID:25871723

  19. Spin relaxation measurements using first-harmonic out-of-phase absorption EPR signals: rotational motion effects.

    PubMed

    Livshits, V A; Marsh, D

    2000-07-01

    A recent survey of nonlinear continuous-wave (CW) EPR methods revealed that the first-harmonic absorption EPR signal, detected 90 degrees out of phase with respect to the Zeeman modulation (V(1)(')-EPR), is the most appropriate for determining spin-lattice relaxation enhancements of spin labels (V. A. Livshits, T. Páli, and D. Marsh, 1998, J. Magn. Reson. 134, 113-123). The sensitivity of such V(1)(')-EPR spectra to molecular rotational motion is investigated here by spectral simulations for nitroxyl spin labels, over the entire range of rotational correlation times. Determination of the effective spin-lattice relaxation times is less dependent on rotational mobility than for other nonlinear CW EPR methods, especially at a Zeeman modulation frequency of 25 kHz which is particularly appropriate for spin labels. This relative insensitivity to molecular motion further enhances the usefulness of the V(1)(')-EPR method. Calibrations of the out-of-phase to in-phase spectral intensity (and amplitude) ratios are given as a function of spin-lattice relaxation time, for the full range of spin-label rotational correlation times. Experimental measurements on spin labels in the slow, intermediate, and fast motional regimes of molecular rotation are used to test and validate the method. PMID:10873499

  20. Phase Rotation Scheme To Combine an RF Technique With Laser-Plasma Interaction For Real Applications Of Laser-Produced Ions

    NASA Astrophysics Data System (ADS)

    Noda, Akira; Iwashita, Yoshihisa; Souda, Hikaru; Tongu, Hiromu; Wakita, Akihisa; Daido, Hiroyuki; Ikegami, Masahiro; Kiriyama, Hiromitsu; Mori, Michiaki; Nishiuchi, Mamiko; Ogura, Koichi; Orimo, Satoshi; Pirozhkov, Alexander; Sagisaka, Akito; Yogo, Akifumi; Shirai, Toshiyuki

    2009-07-01

    A phase rotation scheme of laser-produced ions from a solid target by the application of a synchronized RF electric voltage with a pulsed laser has been experimentally investigated with the use of a 100 TW laser, J-KAREN at JAEA, KPSI. Up to now, energy peaks of up to around 2.0 MeV have been created with a FWHM of 2.6% with good reproducibility using a two-gap resonator of a quarter wave length with the same frequency as the source laser (˜80 MHz). It is also found that the position of the peak can be well controlled by adjusting the relative phase between the RF electric field and the laser, which is very promising for real applications of such laser-produced protons. In order to also apply such a phase rotation system for higher energy protons (<200 MeV), a scheme to use a small linear accelerator (LINAC) with multi-gaps is proposed as a phase rotator. With multi-gap structure, alternating focusing between longitudinal and transverse degrees of freedoms can be realized. From the point of compactness and realizing a small focused spot, however, a scheme combining separate quadrupole magnets just before and after the RF cavity excited with the Wideröe mode, might be more effective. The scheme presented here will realize laser-produced ions (protons) with good reproducibility by combining with RF technology.

  1. 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.

  2. 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}.

  3. Rotating disk electrode system for elevated pressures and temperatures

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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 H2SO4, 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.

  4. Rotating disk electrode system for elevated pressures and temperatures.

    PubMed

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

    2015-06-01

    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 H2SO4, 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. PMID:26133849

  5. 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.

  6. 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.

  7. 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.

  8. Outcomes of a rotational dissection system in gross anatomy.

    PubMed

    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 attend ICM or study independently. For the next laboratory, the assignments were reversed. At the start of the session, the team that had dissected previously spent 30 minutes teaching the other team. In 2012, the students were given three traditional practical examinations with 50 questions drawn equally from each laboratory. Students also completed three mid-course evaluations. There were no significant differences in overall performance between the two teams. Nevertheless, we wanted to determine how well individual students identified structures they had dissected compared with those they had not. For dissected structures, the mean percent correct was 80.0 ± 13.0 (mean ± standard deviation), and for undissected structures, it was 78.3 ± 14.1. The difference was small, but statistically significant (P = 0.0007). Although this result validated the concerns expressed by some students, it did not appear that a change in the system was justified. Students were generally enthusiastic about the opportunity to learn clinical skills in the first semester of medical school, and 91-96% of the students agreed that learning anatomy at the same time helped them understand the physical examination exercises in ICM. PMID:25358463

  9. Fates of Setaria faberi and Abutilon theophrasti seeds in three crop rotation systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed seeds in and on the soil are the primary cause of weed infestations in arable fields. Previous studies have documented reductions in weed seedbanks due to cropping system diversification through extended rotation sequences, but the impacts of different rotation systems on additions to and losse...

  10. 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.

  11. Comparing cropping system productivity of fixed rotations and a flexible fallow system using Aqua-Crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Central High Plains, the predominant crop rotation is winter wheat (Triticum aestivum L.)-fallow. Producers are looking to add diversity and intensity to their cropping systems and improve water use efficiency by adding summer crops, however, the elimination of summer fallow may increase the ...

  12. 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.

  13. A Study on Rotation and Its Application for Attitude Reference System

    NASA Astrophysics Data System (ADS)

    Hasegawa, Ritsuo

    It is well known as the coning effect that even the motion around an axis with no angular rate results in the residual rotation when it resumes the original orientation. However, there has been little investigation concerning the residual rotation when the motion is not closed and does not resume the original orientation. A definition of rotation angle is newly proposed in this paper, and the calculation method of the rotation angle is shown. The new attitude reference system with a one-degree-of-freedom platform was developed using the rotation angle defined in this paper and two parameters showing the rotational axis orientation. The attitude reference system was actually onboard the M-rocket, and it worked well.

  14. Peak-to-average power ratio reduction in all-optical orthogonal frequency division multiplexing system using rotated constellation approach

    NASA Astrophysics Data System (ADS)

    Hmood, Jassim K.; Noordin, Kamarul A.; Arof, Hamzah; Harun, Sulaiman W.

    2015-10-01

    In this paper, a new approach for reducing peak-to-average power ratio (PAPR) based on modulated half subcarriers in all-optical OFDM systems with rotated QAM constellation is presented. To reduce the PAPR, the odd subcarriers are modulated with rotated QAM constellation, while the even subcarriers are modulated with standard QAM constellation. The impact of the rotation angle on the PAPR is mathematically modeled. The effect of PAPR reduction on the system performance is investigated by simulating the all-optical OFDM system, which uses optical coupler-based inverse fast Fourier transform (IFFT)/fast Fourier transform (FFT). The all-optical system is numerically demonstrated with 29 subcarriers. Each subcarrier is modulated by a QAM modulator at a symbol rate of 25 Gsymbol/s. The results reveal that PAPR is reduced with increasing the angle of rotation. The PAPR reduction can reach about 0.8 dB when the complementary cumulative distribution function (CCDF) is 1 × 10-3. Furthermore, both the nonlinear phase noise and the optical signal-to-noise ratio (OSNR) of the system are improved in comparison with the original all-optical OFDM without PAPR reduction.

  15. Adiabatic growth of a black hole in a rotating stellar system

    NASA Technical Reports Server (NTRS)

    Lee, Man Hoi; Goodman, Jeremy

    1989-01-01

    The consequences of slowly adding a massive black hole to the center of a rotating stellar system are considered. Although both the rotation velocity V and the velocity dispersion sigma increase when the black hole is added, the rotation velocity increases faster. The effect goes in the right direction but is too gradual to explain the V/sigma profiles recently observed in several galactic nuclei.

  16. System and Method for Determining Rate of Rotation Using Brushless DC Motor

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2000-01-01

    A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is squared. The squared outputs associated with each winding are combined, with the square root being taken of such combination, to produce a DC output proportional only to the rate of rotation of the motor's shaft.

  17. Displacement, distance, and shape measurements of fast-rotating rough objects by two mutually tilted interference fringe systems.

    PubMed

    Günther, Philipp; Kuschmierz, Robert; Pfister, Thorsten; Czarske, Jürgen W

    2013-05-01

    The precise distance measurement of fast-moving rough surfaces is important in several applications such as lathe monitoring. A nonincremental interferometer based on two mutually tilted interference fringe systems has been realized for this task. The distance is coded in the phase difference between the generated interference signals corresponding to the fringe systems. Large tilting angles between the interference fringe systems are necessary for a high sensitivity. However, due to the speckle effect at rough surfaces, different envelopes and phase jumps of the interference signals occur. At large tilting angles, these signals become dissimilar, resulting in a small correlation coefficient and a high measurement uncertainty. Based on a matching of illumination and receiving optics, the correlation coefficient and the phase difference estimation have been improved significantly. For axial displacement measurements of recurring rough surfaces, laterally moving with velocities of 5 m/s, an uncertainty of 110 nm has been attained. For nonrecurring surfaces, a distance measurement uncertainty of 830 nm has been achieved. Incorporating the additionally measured lateral velocity and the rotational speed, the two-dimensional shape of rotating objects results. Since the measurement uncertainty of the displacement, distance, and shape is nearly independent of the lateral surface velocity, this technique is predestined for fast-rotating objects, such as crankshafts, camshafts, vacuum pump shafts, or turning parts of lathes. PMID:23695313

  18. Antenna-array, phase quadrature tracking system

    NASA Technical Reports Server (NTRS)

    Cubley, H. D.

    1970-01-01

    Phase relationship between input signals appearing on widely-spaced parallel connected antenna elements in array is automatically adjusted in phase quadrature tracking system. Compact and lightweight design permit use in wide variety of airborne communications networks.

  19. 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.

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

    PubMed

    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. PMID:26233156

  1. 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

  2. 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.

  3. CARBON SEQUESTRATION IN SOIL MANAGEMENT AND PLANT ROTATION SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research from Brazil has shown that warm humid climates have great potential to increase soil C. We conducted a 4 yr study on a sandy coastal plain soil in east-central Alabama (USA) to compare economics and soil C storage from various cotton rotations under conservation and conventional tillage. ...

  4. Rotational grazing systems and grazing management research: Mapping the future

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent publication reviewed a substantial amount of evidence generated from a geographically diverse effort by university and agency scientists over the past 6 decades to investigate the impacts of rotational grazing on fundamental rangeland ecological processes. Their findings, and others as well...

  5. All-reflective, highly accurate polarization rotator for high-power short-pulse laser systems.

    PubMed

    Keppler, S; Hornung, M; Bödefeld, R; Kahle, M; Hein, J; Kaluza, M C

    2012-08-27

    We present the setup of a polarization rotating device and its adaption for high-power short-pulse laser systems. Compared to conventional halfwave plates, the all-reflective principle using three zero-phase shift mirrors provides a higher accuracy and a higher damage threshold. Since plan-parallel plates, e.g. these halfwave plates, generate postpulses, which could lead to the generation of prepulses during the subsequent laser chain, the presented device avoids parasitic pulses and is therefore the preferable alternative for high-contrast applications. Moreover the device is easily scalable for large beam diameters and its spectral reflectivity can be adjusted by an appropriate mirror coating to be well suited for ultra-short laser pulses. PMID:23037123

  6. Berry phase in nonlinear systems

    SciTech Connect

    Liu, J.; Fu, L. B.

    2010-05-15

    The Berry phase acquired by an eigenstate that experienced a nonlinear adiabatic evolution is investigated thoroughly. The circuit integral of the Berry connection of the instantaneous eigenstate cannot account for the adiabatic geometric phase, while the Bogoliubov excitations around the eigenstates are found to be accumulated during the nonlinear adiabatic evolution and contribute a finite phase of geometric nature. A two-mode model is used to illustrate our theory. Our theory is applicable to Bose-Einstein condensate, nonlinear light propagation, and Ginzburg-Landau equations for complex order parameters in condensed-matter physics.

  7. 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.

  8. 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.

  9. 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

  10. A Vision-Based Dynamic Rotational Angle Measurement System for Large Civil Structures

    PubMed Central

    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

  11. Phase control system concepts and simulations. [solar power satellite system

    NASA Technical Reports Server (NTRS)

    Lindsay, V. C.

    1980-01-01

    A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier.

  12. 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

  13. 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].

  14. 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.

  15. 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.

  16. 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.

  17. Describing phase coexistence in systems with small phases

    NASA Astrophysics Data System (ADS)

    Lovett, R.

    2007-02-01

    Clusters of atoms can be studied in molecular beams and by computer simulation; 'liquid drops' provide elementary models for atomic nuclei and for the critical nuclei of nucleation theory. These clusters are often described in thermodynamic terms, but the behaviour of small clusters near a phase boundary is qualitatively different from the behaviour at a first order phase transition in idealized thermodynamics. In the idealized case the density and entropy show mathematically sharp discontinuities when the phase boundary is crossed. In large, but finite, systems, the phase boundaries become regions of state space wherein these properties vary rapidly but continuously. In small clusters with a large surface/volume ratio, however, the positive interfacial free energy makes it unlikely, even in states on phase boundaries, that a cluster will have a heterogeneous structure. What is actually seen in these states is a structure that fluctuates in time between homogeneous structures characteristic of the two sides of the phase boundary. That is, structural fluctuations are observed. Thermodynamics only predicts average properties; statistical mechanics is required to understand these fluctuations. Failure to distinguish thermodynamic properties and characterizations of fluctuations, particularly in the context of first order phase transitions, has led to suggestions that the classical rules for thermodynamic stability are violated in small systems and that classical thermodynamics provides an inconsistent description of these systems. Much of the confusion stems from taking statistical mechanical identifications of thermodynamic properties, explicitly developed for large systems, and applying them uncritically to small systems. There are no inconsistencies if thermodynamic properties are correctly identified and the distinction between thermodynamic properties and fluctuations is made clear.

  18. 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

  19. SXLS Phase 2 vacuum system

    SciTech Connect

    Schuchman, J.C.; Chou, T.S.; Halama, H.; Hsieh, H.; Kim, T.; Pjerov, S.; Staicu, F.

    1991-01-01

    Phase 1 of the SXLS (Superconducting X-Ray Lithography Source) is described. It is a room temperature, racetrack-shaped electron storage ring, 8.5 meters in circumference. The Phase 2 design consists of replacing the two room temperature 180{degree} dipole magnets of Phase 1 with superconducting magnets. However, even though superconducting magnets are used, the vacuum chambers within them will operate at room temperature. The chambers are constructed as weldments and are made of INCONEL-625. They are bakeable to 150{degrees}C in-situ and incorporate nine photon beam ports. Each have built-in distributed sputter-ion pumps (DIP), non-evaporable getter (NEG) pumps, beam position monitors, and ion clearing electrodes. R D is underway to optimize the DIP, which much operate at 3.86 Tesla, and to develop a low photo yield coating or treatment for the internal surfaces of the chambers.

  20. The CEBAF fiber optic phase reference system

    SciTech Connect

    Crawford, K.; Simrock, S.; Hovater, C.; Krycuk, A.

    1995-12-31

    The specified phase stability of the CEBAF RF distribution system is 2.9{degree} rms per linac. Stability is achieved through the use of a temperature and pressure regulated coaxial drive line. Purpose of the fiber optic phase reference system is to monitor the relative phase at the beginning and ending of this drive line, between linacs, injector and separator to determine drift due to ambient temperature fluctuations. The system utilizes an Ortel 1310 nm single mode laser driving Sumitumo optical fiber to distribute a reference signal at 1497 MHz. Phase of this reference signal is compared to the 1427 MHz (LO) and the 70 MHz (IF) via a 360{degree} phase detector. The detected information is then routed to the CEBAF control system for display with a specified resolution of {+-}0.2{degree} over a 20{degree} phase delta.

  1. 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.

  2. On linear structure and phase rotation invariant properties of block 2(sup l)-PSK modulation codes

    NASA Technical Reports Server (NTRS)

    Lin, Shu

    1990-01-01

    Two important structural properties of block 2(l)-ary PSK (phase shift keying) modulation codes, linear structure and phase symmetry, are investigated. For an additive white Gaussian noise (AWGN) channel, the error performance of a modulation code depends on its squared Euclidean distance distribution. Linear structure of a code makes the error performance analysis much easier. Phase symmetry of a code is important in resolving carrier phase ambiguity and ensuring rapid carrier phase resynchronization after temporary loss of synchronization. It is desirable for a code to have as many phase symmetries as possible. A 2(l)-ary modulation code is represented here as a code with symbols from the integer group. S sub 2(l) PSK = (0,1,2,...,2(l)-1), under the modulo-2(l) addition. The linear structure of block 2(l)-ary PSK modulation codes over S sub 2(l)-ary PSK with respect to the modulo-2(l) vector addition is defined, and conditions under which a block 2(l)-ary PSK modulation code is linear are derived. Once the linear structure is developed, phase symmetry of a block 2(l)-ary PSK modulation code is studied. It is a necessary and sufficient condition for a block 2(l)-PSK modulation code, which is linear as a binary code, to be invariant under 180 deg/2(l-h) phase rotation, for 1 is less than or equal to h is less than or equal to l. A list of short 8-PSK and 16-PSK modulation codes is given, together with their linear structure and the smallest phase rotation for which a code is invariant.

  3. Correction for nonlinearity and polarization-dependent sensitivity in the detection system of rotating analyzer ellipsometers.

    PubMed

    Russev, S H

    1989-04-15

    Systematic errors due to nonlinearity and polarization-dependent sensitivity in the detection system of rotating analyzer ellipsometers are described. Post Fourier analysis procedures for detection and correction of these effects are presented. PMID:20548687

  4. 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

  5. Phase transition in triglycine sulfate crystals by 1H and 13C nuclear magnetic resonance in the rotating frame

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran; Jeong, Se-Young

    2013-09-01

    The ferroelectric phase transition in triglycine sulfate ((NH2CH2COOH)3·H2SO4, TGS)) crystals, occurring at TC of 322 K, was studied using 1H and 13C CP/MAS NMR. From the spin-lattice relaxation time in the rotating frame, T1ρ, of 1H and 13C, we found that the slopes of the T1ρ versus temperature curve changed near TC. In addition, the change of intensities for the protons and carbons NMR signals in the ferroelectric and the paraelectric phases led to the noticeable changes in the environments of proton and carbon in the carboxyl groups. The carboxyl ordering was the dominant factor driving the phase transition. Our study of the 1H and 13C spectra showed that the ferroelectric phase transition of TGS is of the order-disorder type due to ordering of the carboxyl groups.

  6. Ultramicrowave communications system, phase 3

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The ultramicrowave communications system program investigated the feasibility of a solid state system that meets the projected space to space requirements, while using the advantages of the 100 to 200 GHz band. The program successfully demonstrated a laboratory model of a high frequency communications system operating between 100 to 200 GHz. In the process, vendor claims for performance specifications of discrete components were evaluated, and a window was provided into system design and integration problems.

  7. 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.

  8. 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.

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

    PubMed

    Huang, Jianzhang; Han, Qiang

    2016-04-15

    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. PMID:26934619

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Anisotropic phase-mixing in homogeneous turbulence in a rapidly rotating or in a strongly stratified fluid: An analytical study

    NASA Astrophysics Data System (ADS)

    Salhi, A.; Cambon, C.

    2007-05-01

    Angular phase mixing in rapidly rotating or in strongly stratified flows is quantified for single-time single-point energy components, using linear theory. In addition to potential energy, turbulent kinetic energy is more easily analyzed in terms of its toroidal and poloidal components, and then in terms of vertical and horizontal components. Since the axial symmetry around the direction n (which bears both the system angular velocity and the mean density gradient) is consistent with basic dynamical equations, the input of initial anisotropy is investigated in the axisymmetric case. A general way to construct axisymmetric initial data is used, with a classical expansion in terms of scalar spherical harmonics for the 3D spectral density of kinetic energy e, and a modified expansion for the polarization anisotropy Z, which reflects the unbalance in terms of poloidal and toroidal energy components. The expansion involves Legendre polynomials of arbitrary order, P2n0(cosθ), (n=0,1,2,…,N0), in which the term [cosθ=(k•n)/∣k∣] characterizes the anisotropy in k-wavespace; two sets of parameters, β2n(e) and β2n(z), separately generate the directional anisotropy and the polarization anisotropy. In the rotating case, the phase mixing results in damping the polarization anisotropy, so that toroidal and poloidal energy components asymptotically equilibrate after transient oscillations. Complete analytical solutions are found in terms of Bessel functions. The envelope of these oscillations decay with time like (ft)-2 (f being the Coriolis parameter), whereas those for the vertical and horizontal components decay like (ft)-3. The long-time limit of the ratio of horizontal component to vertical one depends only on β2(e), which is eventually related to a classical component in structure-based modeling, independently of the degree of the expansion of the initial data. For the stratified case, both the degree of initial anisotropy and the initial unbalance in terms of

  15. 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.

  16. Rotational spectra and gas phase structure of the maleimide - Formic acid doubly hydrogen bonded dimer

    NASA Astrophysics Data System (ADS)

    Pejlovas, Aaron M.; Kukolich, Stephen G.

    2016-03-01

    Rotational transitions were measured for the maleimide - formic acid doubly hydrogen bonded dimer using a Flygare-Balle type pulsed-beam Fourier transform microwave spectrometer. No splittings caused by possible concerted double proton tunneling motion were observed. Experimental rotational constants (MHz), quadrupole coupling constants (MHz), and centrifugal distortion constants (kHz) were determined for the parent and three deuterium substituted isotopologues. The values for the parent are A = 2415.0297(10), B = 784.37494(38), C = 592.44190(33), DJ = 0.0616(64), DJK = -0.118(35), DK = -1.38(15), 1.5χaa = 2.083(14), and 0.25(χbb-χcc) = 1.1565(29). The hydrogen bond lengths were determined using a nonlinear least squares structure fitting program. Rotational constants for this complex are consistent with a planar structure, with an inertial defect of Δ = -0.528 amu Å2. The B3LYP calculation yielded rotational constants within 0.1% of the experimental values.

  17. 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.

  18. 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

  19. 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.

  20. Coupled phase transformations and plastic flows under torsion at high pressure in rotational diamond anvil cell: Effect of contact sliding

    NASA Astrophysics Data System (ADS)

    Feng, Biao; Levitas, Valery I.

    2013-12-01

    A three-dimensional large-sliding contact model coupled with strain-induced phase transformations (PTs) and plastic flow in a disk-like sample under torsion at high pressure in rotational diamond anvil cell (RDAC) is formulated and studied. Coulomb and plastic friction are combined and take into account variable parameters due to PT. Results are obtained for weaker, equal-strength, and stronger high pressure phases, and for three values of the kinetic coefficient in a strain-controlled kinetic equation and friction coefficient. All drawbacks typical of problem with cohesion are overcome, including eliminating mesh-dependent shear band and artificial plastic zones. Contact sliding intensifies radial plastic flow, which leads to larger reduction in sample thickness. Larger plastic strain and increased pressure in the central region lead to intensification of PT. However, the effect of the reduction in the friction coefficient on PT kinetics is nonmonotonous. Sliding increases away from the center and with growing rotation and is weakly dependent on the kinetic coefficient. Also, cyclic back and forth torsion is studied and compared to unidirectional torsion. Multiple experimental phenomena, e.g., pressure self-multiplication effect, steps (plateaus) at pressure distribution, flow to the center of a sample, and oscillatory pressure distribution for weaker high-pressure phase, are reproduced and interpreted. Reverse PT in high pressure phase that flowed to the low pressure region is revealed. Possible misinterpretation of experimental PT pressure is found. Obtained results represent essential progress toward understanding of strain-induced PTs under compression and shear in RDAC and may be used for designing experiments for synthesis of new high pressure phases and reduction in PT pressure for known phases, as well as for determination of PT kinetics from experiments.

  1. Phase growth in bistable systems with impurities.

    PubMed

    Echeverria, C; Tucci, K; Cosenza, M G

    2008-01-01

    A system of coupled chaotic bistable maps on a lattice with randomly distributed impurities is investigated as a model for studying the phenomenon of phase growth in nonuniform media. The statistical properties of the system are characterized by means of the average size of spatial domains of equivalent spin variables that define the phases. It is found that the rate at which phase domains grow becomes smaller when impurities are present and that the average size of the resulting domains in the inhomogeneous state of the system decreases when the density of impurities is increased. The phase diagram showing regions where homogeneous, heterogeneous, and chessboard patterns occur on the space of parameters of the system is obtained. A critical boundary that separates the regime of slow growth of domains from the regime of fast growth in the heterogeneous region of the phase diagram is calculated. The transition between these two growth regimes is explained in terms of the stability properties of the local phase configurations. Our results show that the inclusion of spatial inhomogeneities can be used as a control mechanism for the size and growth velocity of phase domains forming in spatiotemporal systems. PMID:18351923

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. Phase and time-resolved measurements of unsteady heat transfer and pressure in a full-stage rotating turbine

    NASA Technical Reports Server (NTRS)

    Dunn, M. G.

    1989-01-01

    This paper presents detailed phase-resolved heat-flux data obtained on rotor blades and a comparison of simultaneously obtained time-resolved heat-flux and static pressure data obtained on the stationary shroud of a Garrett TFE 731-2 HP full-stage rotating turbine. A shock tube is used to generate a short-duration source of heated and pressurized air and platinum thin-film gages are used to obtain heat-flux measurements. Blade results are presented at several selected blade locations. Shroud surface pressure and heat-flux time histories are presented for comparable locations relative to the blade position.

  12. 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

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

    NASA Technical Reports Server (NTRS)

    Oren, Abraham L.; Wolfe, Arthur M.

    1995-01-01

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

  14. 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.

  15. Effects of differential rotation on the periods of small adiabatic oscillations of stars in binary systems.

    NASA Astrophysics Data System (ADS)

    Singh, V. P.; Sharma, M. K.

    1996-01-01

    Presents a method for computing the eigenfrequencies of small adiabatic oscillations of stellar models distorted by differential rotation and tidal forces. The method is based on the approach adopted by Mohan and Singh (1982) in conjunction with the averaging concept introduced by Kippenhahn and Thomas (1970). The angular velocity of rotation is assumed to be the function of the square of the distance of fluid element from the axis of rotation. Tidal distortions are assumed to be caused by a nearby point mass. Such studies have practical importance in astrophysics in determining the periods of small adiabatic oscillations of differentially rotating stars in binary systems. Comparison of results with observational data is also presented.

  16. 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.

  17. 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.

  18. Phase diagram and dynamics of Yukawa systems

    NASA Astrophysics Data System (ADS)

    Robbins, Mark. O.; Kremer, Kurt; Grest, Gary S.

    1988-03-01

    The phase diagram and dynamical properties of systems of particles interacting through a repulsive screened Coulomb (Yukawa) potential have been calculated using molecular and lattice dynamics techniques. The phase diagram contains both a melting transition and a transition from fcc to bcc crystalline phases. These phase transitions have been studied as a function of potential shape (screening length) and compared to phenomenological criteria for transition temperatures such as those of Lindemann and of Hansen and Verlet. The transition from fcc to bcc with increasing temperature is shown to result from a higher entropy in the bcc phase because of its softer shear modes. Even when the stable solid phase below the melting temperature is fcc, bcc-like local order is found in the liquid phase. This may substantially slow crystallization. The calculated phase diagram and shear modulus are in good agreement with experiments on colloidal suspensions of polystyrene spheres. The single particle dynamics of Yukawa systems show several unusual features. There is a pronounced subdiffusive regime in liquids near and below the melting temperature. This regime reflects the existence of two time scales: a typical phonon period, and the time for a particle to feel a new environment. The second time scale becomes longer as the temperature is lowered or the range of interaction (screening length) increases.

  19. 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

  20. 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

  1. 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.

  2. Monitoring the rotation status of wind turbine blades using high-speed camera system

    NASA Astrophysics Data System (ADS)

    Zhang, Dongsheng; Chen, Jubing; Wang, Qiang; Li, Kai

    2013-06-01

    The measurement of the rotating object is of great significance in engineering applications. In this study, a high-speed dual camera system based on 3D digital image correlation has been developed in order to monitor the rotation status of the wind turbine blades. The system allows sequential images acquired at a rate of 500 frames per second (fps). An improved Newton-Raphson algorithm has been proposed which enables detection movement including large rotation and translation in subpixel precision. The simulation experiments showed that this algorithm is robust to identify the movement if the rotation angle is less than 16 degrees between the adjacent images. The subpixel precision is equivalent to the normal NR algorithm, i.e.0.01 pixels in displacement. As a laboratory research, the high speed camera system was used to measure the movement of the wind turbine model which was driven by an electric fan. In the experiment, the image acquisition rate was set at 387 fps and the cameras were calibrated according to Zhang's method. The blade was coated with randomly distributed speckles and 7 locations in the blade along the radial direction were selected. The displacement components of these 7 locations were measured with the proposed method. Conclusion is drawn that the proposed DIC algorithm is suitable for large rotation detection, and the high-speed dual camera system is a promising, economic method in health diagnose of wind turbine blades.

  3. 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.

  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. 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.

  6. Phase control of intermittency in dynamical systems.

    PubMed

    Zambrano, Samuel; Mariño, Inés P; Salvadori, Francesco; Meucci, Riccardo; Sanjuán, Miguel A F; Arecchi, F T

    2006-07-01

    We present a nonfeedback method to tame or enhance crisis-induced intermittency in dynamical systems. By adding a small harmonic perturbation to a parameter of the system, the intermittent behavior can be suppressed or enhanced depending on the value of the phase difference between the main driving and the perturbation. The validity of the method is shown both in the model and in an experiment with a CO2 laser. An analysis of this scheme applied to the quadratic map near crisis illustrates the role of phase control in nonlinear dynamical systems. PMID:16907172

  7. 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.

  8. 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.

  9. From Infall to Rotation around Young Stellar Objects: A Transitional Phase with a 2000 AU Radius Contracting Disk?

    NASA Astrophysics Data System (ADS)

    Hogerheijde, Michiel R.

    2001-06-01

    Evidence for a transitional stage in the formation of a low-mass star is reported, intermediate between the fully embedded and the T Tauri phases. Millimeter aperture synthesis observations in the HCO+ J=1-0 and 3-2, HCN 1-0, 13CO 1-0, and C18O 1-0 transitions reveal distinctly different velocity fields around two embedded, low-mass young stellar objects. The 0.6 Msolar of material around TMC 1 (IRAS 04381+2517) closely follows inside-out collapse in the presence of a small amount of rotation (~3 km s-1 pc-1), while L1489 IRS (IRAS 04016+2610) is surrounded by a 2000 AU radius, flared disk containing 0.02 Msolar. This disk shows Keplerian rotation around a ~0.65 Msolar star and infall at 1.3(r/100 AU)-0.5 km s-1, or, equivalently, sub-Keplerian motions around a central object between 0.65 and 1.4 Msolar. Its density is characterized by a radial power law and an exponential vertical scale height. The different relative importance of infall and rotation around these two objects suggests that rotationally supported structures grow from collapsing envelopes over a few times 105 yr to sizes of a few thousand AU, and then decrease over a few times 104 yr to several hundred AU typical for T Tauri disks. In this scenario, L1489 IRS represents a transitional phase between embedded young stellar objects and T Tauri stars with disks. The expected duration of this phase of ~5% of the embedded stage is consistent with the current lack of other known objects like L1489 IRS. Alternative explanations cannot explain L1489 IRS's large disk, such as formation from a cloud core with an unusually large velocity gradient or a binary companion that prevents mass accretion onto small scales. It follows that the transfer and dissipation of angular momentum is key to understanding the formation of disks from infalling envelopes.

  10. 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.

  11. 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.

  12. 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.

  13. A Novel Phase Rotation Scheme on the Constellations for the E-UTRA Uplink ACK/NACK Signals

    NASA Astrophysics Data System (ADS)

    Nakao, Seigo; Takata, Tomohumi; Imamura, Daichi; Hiramatsu, Katsuhiko

    Hybrid automatic repeat request (HARQ) is employed for the Evolved Universal Terrestrial Radio Access (E-UTRA) downlink. The ACK/NACK signals from each user equipment (UE) are multiplexed by code division multiple access (CDMA) and transmitted via a physical uplink control channel (PUCCH). The ACK/NACK signals are code spread by the cyclic shift (CS) sequences made from zero auto-correlation (ZAC) sequences; however, the orthogonality of these sequences is not guaranteed depending on the propagation channels; moreover, the amount of inter-code interference (ICI) depends on the delay spread of the channel and the transmitting timing control error of each UE. In the conventional PUCCH structure, ICI between two ACK signals does not degrade their detection performance, whereas ICI between an ACK signal and a NACK signal degrades the detection performance. This causes a serious gap between the detection performances of ACK and NACK signals, because generally in a PUCCH, there are more ACK signals than NACK signals. In this paper, we propose a novel phase rotation scheme on the constellations of ACK/NACK signals that can resolve this issue, and the simulation evaluation results confirm the benefits of the proposed phase rotation scheme.

  14. 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. PMID:24949649

  15. 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)

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 3D shape and eccentricity measurements of fast rotating rough objects by two mutually tilted interference fringe systems

    NASA Astrophysics Data System (ADS)

    Czarske, J. W.; Kuschmierz, R.; Günther, P.

    2013-06-01

    Precise measurements of distance, eccentricity and 3D-shape of fast moving objects such as turning parts of lathes, gear shafts, magnetic bearings, camshafts, crankshafts and rotors of vacuum pumps are on the one hand important tasks. On the other hand they are big challenges, since contactless precise measurement techniques are required. Optical techniques are well suitable for distance measurements of non-moving surfaces. However, measurements of laterally fast moving surfaces are still challenging. For such tasks the laser Doppler distance sensor technique was invented by the TU Dresden some years ago. This technique has been realized by two mutually tilted interference fringe systems, where the distance is coded in the phase difference between the generated interference signals. However, due to the speckle effect different random envelopes and phase jumps of the interference signals occur. They disturb the phase difference estimation between the interference signals. In this paper, we will report on a scientific breakthrough on the measurement uncertainty budget which has been achieved recently. Via matching of the illumination and receiving optics the measurement uncertainty of the displacement and distance can be reduced by about one magnitude. For displacement measurements of a recurring rough surface a standard deviation of 110 nm were attained at lateral velocities of 5 m / s. Due to the additionally measured lateral velocity and the rotational speed, the two-dimensional shape of rotating objects is calculated. The three-dimensional shape can be conducted by employment of a line camera. Since the measurement uncertainty of the displacement, vibration, distance, eccentricity, and shape is nearly independent of the lateral surface velocity, this technique is predestined for fast-rotating objects. Especially it can be advantageously used for the quality control of workpieces inside of a lathe towards the reduction of process tolerances, installation times and

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. The synchronous rotations of Eris/Dysnomia and Orcus/Vanth binary systems

    NASA Astrophysics Data System (ADS)

    Rabinowitz, David L.; Owainati, Yasi

    2014-11-01

    We have measured the rotation periods of the Eris/Dysnomia and Orcus/Vanth binary systems using long-term observations obtained with the SMARTS 1.3m telescope at Cerro Tololo, combined with incidental observations obtained by the La Silla - QUEST survey on the ESO 1.0-m Schmidt at La Silla, and using historical observations of Eris published by others. We find that both binary systems are synchronous, with the dominant periodicity in their light curves matching their mutual orbit periods (9.54 and 15.774 days, respectively). For Orcus/Vanth, the reflected light from both bodies contributes to the signal. The measured periodicity could be due to the rotation of Orcus or Vanth separately, but it is most likely the system is doubly synchronous. For Eris/Dysnomia, only Eris is bright enough to contribute significantly to the observations. The conclusion is therefore unambiguous that Eris is synchronously rotating with the orbit of Dysnomia. This is surprising given that Eris is 500 times brighter than Dysnomia, and likely to be 100 to 10000 times more massive (assuming an albedo > 5% for Dysnomia). If Dysnomia has migrated outward from Eris owing to long-term tidal interactions, the time for Eris to slow from an initially fast rotation (period < 1 day) to a synchronous one is longer than the age of the solar system. We discuss the constraints these observations place on the relative albedos, masses, and internal composition of the two binary systems.

  9. 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.

  10. 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.

  11. Conservation of `Moving' Energy in Nonholonomic Systems with Affine Constraints and Integrability of Spheres on Rotating Surfaces

    NASA Astrophysics Data System (ADS)

    Fassò, Francesco; Sansonetto, Nicola

    2016-04-01

    Energy is in general not conserved for mechanical nonholonomic systems with affine constraints. In this article we point out that, nevertheless, in certain cases, there is a modification of the energy that is conserved. Such a function is the pull-back of the energy of the system written in a system of time-dependent coordinates in which the constraint is linear, and for this reason will be called a `moving' energy. After giving sufficient conditions for the existence of a conserved, time-independent moving energy, we point out the role of symmetry in this mechanism. Lastly, we apply these ideas to prove that the motions of a heavy homogeneous solid sphere that rolls inside a convex surface of revolution in uniform rotation about its vertical figure axis, are (at least for certain parameter values and in open regions of the phase space) quasi-periodic on tori of dimension up to three.

  12. 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.

  13. 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

  14. Contraction and Fragmentation of Magnetized Rotating Clouds and Formation of Binary Systems

    NASA Astrophysics Data System (ADS)

    Tomisaka, Kohji; Machida, Masahiro N.; Matsumoto, Tomoaki

    2004-08-01

    Using three-dimensional (3D) magnetohydrodynamical (MHD) nested-grid simulations, the fragmentation of a rotating magnetized molecular cloud core is studied. An isothermal rotating magnetized cylindrical cloud in hydrostatic balance is considered. We studied non-axisymmetric evolution of the cloud. It is found that non-axisymmetry hardly evolves in the early phase, but it begins to grow after the gas contracts and forms a thin disk. The disk formation and thus growth of non-axisymmetric perturbation are strongly promoted by rotation and magnetic field strength. We found two types of fragmentations: fragmentation from a ring and that from a bar. These two types of fragmentations occur in thin adiabatic cores with the thickness being smaller than 1/4 of the radial size. For the fragments to survive, they should be formed in a heavily elongated barred core or a flat round disk. In the models showing fragmentation, outflows from respective fragments are found as well as that driven by the rotating bar or the disk.

  15. 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)...

  16. 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...

  17. Simulating Alternative Dryland Rotational Cropping Systems in the Central Great Plains with RZWQM2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term crop rotation effects on crop water use and yield have been investigated in the Central Great Plains since the 1990s. System models are needed to synthesize these long-term results for making management decisions and for transferring localized data to other conditions. The objectives of th...

  18. 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.

  19. 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.

  20. TILLAGE AND ROTATION EFFECTS ON ENERGY BALANCES IN CORN AND SOYBEAN SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limited information is available regarding the effect of common management practices on the energy balance of corn and soybean cropping systems. Energy balances were calculated for continuous corn, continuous soybean, and corn-soybean rotations under six tillage treatments that included no-tillage, ...

  1. 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.

  2. Effect of Shear Strain on the α-ε Phase Transition of Iron: a New Approach in the Rotational Diamond Anvil Cell

    SciTech Connect

    Ma,Y.; Selvi, E.; Levitas, V.; Hashemi, J.

    2006-01-01

    The effect of shear strain on the iron {alpha}-{var_epsilon} phase transformation has been studied using a rotational diamond anvil cell (RDAC). The initial transition is observed to take place at the reduced pressure of 10.8 GPa under pressure and shear operation. Complete phase transformation was observed at 15.4 GPa. The rotation of an anvil causes limited pressure elevation and makes the pressure distribution symmetric in the sample chamber before the phase transition. However, it causes a significant pressure increase at the center of the sample and brings about a large pressure gradient during the phase transformation. The resistance to the phase interface motion is enhanced due to strain hardening during the pressure and shear operations on iron and this further increases the transition pressure. The work of macroscopic shear stress and the work of the pressure and shear stress at the defect tips account for the pressure reduction of the iron phase transition.

  3. 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.

  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. 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

  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. 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

  8. Phase-Compensating System For Fiber-Optic Holography

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Beheim, Glenn

    1990-01-01

    Phase-compensating system controls relative phase of laser light emitted from two optical fibers. Stabilized for conventional holographic applications, or stepped through sequence of 90 degree phase shifts for phase-stepping holographic interferometry. Closed-loop system compensates for phase fluctuations caused by mechanical stresses and temperature changes in fibers, providing long-term phase stability and phase steps accurate to within 0.02 degrees. Controls environmental fluctuations in phases of light emitted by output fibers.

  9. 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

  10. Selective control of the states of multilevel quantum systems using nonselective rotation operators

    SciTech Connect

    Zobov, V. E. Shauro, V. P.

    2009-01-15

    We have calculated the sequences of nonselective rotation operators separated by intervals of free evolution that perform selective rotations between adjacent levels in systems with three, four, five, and six nonequidistant levels. We have numerically simulated the realization of the calculated sequences for quadrupole nuclei with corresponding spins controlled by intense nonselective radio-frequency (RF) pulses and investigated the dependences of the realization error on the parameters of external and internal interactions. To reduce the error when the RF field is not strong enough, we have found composite nonselective RF pulses consisting of five simple ones. We show that the error of the composite selective rotation operator can be reduced signifi- cantly in comparison to the error of a simple single selective pulse.

  11. 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.

  12. First-order phase transition and high energy cyclonic spots in a shallow water model on a rapidly rotating sphere

    NASA Astrophysics Data System (ADS)

    Ding, Xueru; Lim, Chjan C.

    2009-04-01

    A statistical equilibrium theory based on the Lagrangian of the rotating shallow water equations is presented with applications to cooperative properties of large-scale features in the Jovian atmosphere when the flows have pronounced hemispherical asymmetry. Large planetary spin is shown to play a significant role in the orientation asymmetry or energy gap between cyclonic and anticyclonic vorticity distributions. This suggests that angular momentum is the key physical factor behind the statistical preference for a cyclonic vorticity distribution at high levels of flow energy. Simulation results reported here show that for a range of high energy-to-enstrophy ratios at Jupiter's parameters, a broad-based cyclonic vortex forms in one of the hemisphere with few other coherent spots. Evidence that this cooperative phenomenon arise from a first-order phase transition is discussed.

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

    NASA Astrophysics Data System (ADS)

    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 Script M. Then, we compare our prediction for langledot varpirangle 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 |Ψz| <= 0.0006-0.013 arcsec cty-1, |Ψx| <= 0.1-2.7 arcsec cty-1, |Ψy| <= 0.3-2.3 arcsec cty-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 H0 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 Ψz 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.

  14. a Nucleoside Under Observation in the Gas Phase: a Rotational Study of Uridine

    NASA Astrophysics Data System (ADS)

    Peña, Isabel; Alonso, José L.

    2014-06-01

    The nucleoside of uridine has been placed in the gas phase by laser ablation and the most stable C2{'}-anti conformation characterized by broadband chirped pulse (CP-FTMW) and narrowband molecular beam Fourier transform microwave (LA-MB-FTMW) spectroscopies. The quadrupole hyperfine structure, originated by two 14N nuclei, has been completely resolved. Intramolecular hydrogen bonds involving uracil and ribose moieties have been found to play an important role in the stabilization of the nucleoside.

  15. 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

  16. Prone breast tumor imaging using vertical axis-of-rotation (VAOR) SPECT systems: An initial study

    SciTech Connect

    Wang, Huili; Scarfone, C.; Greer, K.L.; Coleman, R.E.

    1996-12-31

    We propose the use of a single photon emission computed tomography (SPECT) system equipped with multiple cameras revolving around a vertical axis-of-rotation (VAOR) to image tumors in a prone-dependent breast. This innovative breast imaging approach has the advantages of a small attenuation volume between breast lesions and gamma detector as well as a minimal radius-of-rotation compared to conventional (horizontal axis-of-rotation) breast SPECT. Small attenuation volume results in improved detected counts and minimal radius-of-rotation leads to increased collimator resolution. Because of no VAOR SPECT system currently available, we conducted our experiments on a conventional SPECT system using an isolated breast phantom to investigate the proposed VAOR breast SPECT. Our experimental setup simulated a VAOR SPECT study with a prone-dependent breast in the camera`s field-of-view. The results of our experiment indicate that VAOR breast SPECT with Trionix LESR parallel hole collimator is capable of detecting a breast lesion with a diameter of 10 mm and a lesion-to-background concentration ratio of 6 to 1. The results also demonstrate that VAOR breast SPECT provides improved lesion visualization over planar scintimammography and conventional breast SPECT.

  17. Robust unidirectional rotation in three-tooth Brownian rotary ratchet systems

    NASA Astrophysics Data System (ADS)

    Tutu, Hiroki; Nagata, Soichiro

    2013-02-01

    We apply a simple Brownian ratchet model to an artificial molecular rotary system mounted in a biological membrane, in which the rotor always maintains unidirectional rotation in response to a linearly polarized weak ac field. Because the rotor and stator compose a ratchet system, we describe the motion of the rotor tip with the Langevin equation for a particle in a two-dimensional three-tooth ratchet potential of threefold symmetry. Unidirectional rotation can be induced under the field and optimized by stochastic resonance, wherein the mean angular momentum (MAM) of the rotor exhibits a bell-shaped curve for the noise strength. We obtain analytical expressions for the MAM and power loss from the corresponding Fokker-Planck equation, via a Markov transition model for coarse-grained states (six-state model). The MAM expression reveals a significant effect depending on the chirality of the ratchet potential: in achiral cases, the MAM approximately vanishes with respect to the polarization angle ϕ of the field; in chiral cases, the MAM does not crucially depend on ϕ, but depends on the direction of the ratchet; i.e., the parity of the unidirectional rotation is inherent in the ratchet structure. This feature is useful for artificial rotary systems to maintain robust unidirectional rotation independent of the mounting condition.

  18. Development of a rotary instrumentation system, phase 2

    NASA Technical Reports Server (NTRS)

    Adler, A.; Skidmore, W.

    1982-01-01

    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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. Quantum phase transitions in frustrated magnetic systems

    NASA Astrophysics Data System (ADS)

    Wölfle, P.; Schmitteckert, P.

    2015-07-01

    We review our recent work on quantum phase transitions in frustrated magnetic systems. In the first part a Pseudo Fermion Functional Renormalization Group (PFFRG) method is presented. By using an exact representation of spin 1/2 operators in terms of pseudofermions a quantum spin Hamiltonian may be mapped onto an interacting fermion system. For the latter an FRG treatment is employed. The results for the J1-J2 model and similar models of frustrated interaction show phase diagrams in agreement with those obtained by other methods, but give more detailed information on the nature of correlations, in particular in the non-magnetic phases. Applications of PFFRG to geometrically frustrated systems and to highly anisotropic Kitaev type models are also reported. In the second part the derivation of quantum spin models from the microscopic many-body Hamiltonian is discussed. The results for multiband systems with strong spin-orbit interaction encountered in the iridates class of compounds are shown to resolve some of the questions posed by experiment.

  5. 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…

  6. Flow between Rotating Cylinders as a Model of Instability in Nonequilibrium Systems

    NASA Astrophysics Data System (ADS)

    Rodenborn, Bruce; Swinney, Harry L.

    2010-03-01

    The study of flow between rotating concentric cylinders (Couette-Taylor flow) began over a century ago and has been conducted by giants in the fields of fluid mechanics and astrophysics such as Lord Rayleigh, G.I. Taylor, and S. Chandreshekar. The system still yields seminal findings in fluid turbulence, hydrodynamic stability theory, plasma physics and chaos theory. It is also a model system for instabilities that arise in proto-planetary and proto-solar disks, the earth's core and other important applications. Simple geometry makes the base fluid state at low rotation rates analytically solvable at an undergraduate level, which belies the zoo of instabilities and patterns that develop for higher rotation rates. Low-cost cameras and open source software make a well-instrumented experiment possible for a few hundred dollars. Just as the Couette-Taylor system provides a valuable model for instability in systems driven away from thermodynamic equilibrium, it also serves as a valuable model experiment that builds important scientific abilities including: instrument control, data acquisition, image analysis, Fourier spectral analysis and other experimental skills. I use a Couette-Taylor system in annual winter schools on experimental physics, ``Hands-On Research in Complex Systems'' conducted in developing countries to stimulate interest in low-cost, table-top experimental physics.

  7. 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.

  8. Bifurcation and chaos analysis of a nonlinear electromechanical coupling relative rotation system

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Zhao, Shuang-Shuang; Sun, Bao-Ping; Zhang, Wen-Ming

    2014-09-01

    Hopf bifurcation and chaos of a nonlinear electromechanical coupling relative rotation system are studied in this paper. Considering the energy in air-gap field of AC motor, the dynamical equation of nonlinear electromechanical coupling relative rotation system is deduced by using the dissipation Lagrange equation. Choosing the electromagnetic stiffness as a bifurcation parameter, the necessary and sufficient conditions of Hopf bifurcation are given, and the bifurcation characteristics are studied. The mechanism and conditions of system parameters for chaotic motions are investigated rigorously based on the Silnikov method, and the homoclinic orbit is found by using the undetermined coefficient method. Therefore, Smale horseshoe chaos occurs when electromagnetic stiffness changes. Numerical simulations are also given, which confirm the analytical results.

  9. [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

  10. 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.

  11. 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).

  12. 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.

  13. 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.

  14. 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%.

  15. 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.

  16. 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.

  17. Automated phase/amplitude EHF measurement system

    NASA Astrophysics Data System (ADS)

    Potts, B. M.

    1981-05-01

    An automated, computer-controlled measurement system capable of conducting transmission and reflection measurements on components over the 40 to 47 GHz frequency range is described. The measurement system utilizes harmonic mixing in conjunction with a phase locked, dual channel receiver to downconvert signals in the 7 GHz bandwidth to a lower intermediate frequency (1 KHz) where phase and amplitude measurements are made. The system is capable of operating over a dynamic range in excess of 50 dB when used with an EHF source producing a minimum -10 dBm output. Following a description of the system and its operation, some performance characteristics are presented. The measurement system accuracy is demonstrated using two types of reference standards: (1) a rotary vane attenuator for the transmission measurements, and (2) a set of reduced-height waveguide VSWR standards for the return loss measurements. Results obtained using these standards have indicated that measurement accuracies of 0.25 dB and 3 deg are achievable over a 50 dB dynamic range.

  18. 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.

  19. 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.

  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. 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.

  2. 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

  3. Ray Tracing Through Non-Rotationally Symmetrical Systems With A Desktop Computer

    NASA Astrophysics Data System (ADS)

    Mackay, R. M.; Busse lle, F. J.

    1986-10-01

    A general ray-trace program has been developed for use on a desktop computer which traces finite rays through any non-rotationally symmetrical system. In particular any combination of decentred, tilted and rotated surface has been considered. Surface types such as Conic sections with and without Aspherics, Toric surfaces, surfaces of S and T Cylindrical sections, and Axicons, may be ray-traced. Each surface is defined in terms of a local rectangular co-ordinate system and has a particular aperture shape attributed to it. Aperture shapes may be defined as circular, elliptical, rectangular or quadrilateral. Also the centre of any aperture shape may be displaced from its local coordinate origin to facilitate the tracing of off-axis paraboloids. Before transferring to the next surface, the local coordinates are referred back to an initial reference coordinate system. Finally a means of assessing aberrations has been included. The main task here was to get a mathematical model of a non-rotationally symmetrical finite ray-trace running on an inexpensive desk top computer. The program was written for the BBC MICRO in order to investigate devices such as scanning systems for modern Thermal Imagers etc.

  4. 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.

  5. 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.

  6. Strike-slip faulting and block rotation in the Lake Mead fault system

    NASA Astrophysics Data System (ADS)

    Ron, Hagai; Aydin, Atilla; Nur, Amos

    1986-12-01

    Strike-slip faults in the Basin and Range province have often been considered passive boundaries between differentially extended domains of tilted normal faults and are thus considered secondary in accommodating regional horizontal deformation. Paleomagnotic investigation of late Miocene age volcanic rocks, displaced by the left-lateral fault system of Lake Mead, Nevada, shows: (1) that these rocks have not been affected by significant structural tilt, the difference between observed and expected inclinations being only -0.6° ± 14.9° and (2) a significant horizontal counterclockwise rotation of -29.4° ± 8.5° about a vertical axis. This rotation was accommodated by slip on northwest-trending, right-lateral strike-slip faults; this implies significant west-northwest elongation. Results of the investigation indicate that strike-slip faulting is the primary process accommodating crustal deformation along the Lake Mead fault system and that tilting in response to normal faulting is secondary.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. Quantum speed limits in open systems: Non-Markovian dynamics without rotating-wave approximation

    PubMed Central

    Sun, Zhe; Liu, Jing; Ma, Jian; Wang, Xiaoguang

    2015-01-01

    We derive an easily computable quantum speed limit (QSL) time bound for open systems whose initial states can be chosen as either pure or mixed states. Moreover, this QSL time is applicable to either Markovian or non-Markovian dynamics. By using of a hierarchy equation method, we numerically study the QSL time bound in a qubit system interacting with a single broadened cavity mode without rotating-wave, Born and Markovian approximation. By comparing with rotating-wave approximation (RWA) results, we show that the counter-rotating terms are helpful to increase evolution speed. The problem of non-Markovianity is also considered. We find that for non-RWA cases, increasing system-bath coupling can not always enhance the non-Markovianity, which is qualitatively different from the results with RWA. When considering the relation between QSL and non-Markovianity, we find that for small broadening widths of the cavity mode, non-Markovianity can increase the evolution speed in either RWA or non-RWA cases, while, for larger broadening widths, it is not true for non-RWA cases. PMID:25676589

  13. Gas-phase temperature measurement in the vaporizing spray of a gasoline direct-injection injector by use of pure rotational coherent anti-Stokes Raman scattering.

    PubMed

    Beyrau, Frank; Bräuer, Andreas; Seeger, Thomas; Leipertz, Alfred

    2004-02-01

    Pure rotational coherent anti-Stokes Raman spectroscopy is applied for quantitative gas-phase temperature measurements in the vaporizing spray of an automotive fuel injector. Interferences from elastically scattered stray light are greatly reduced by use of a polarization technique and spectral filtering in a double monochromator. The applicability of this technique to probing low-temperature sprays is successfully demonstrated. PMID:14759040

  14. 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.

  15. A dissipative model of solar system and stability of stationary rotations

    NASA Astrophysics Data System (ADS)

    Vilke, V. G.

    2009-04-01

    In classical model of Solar system the planets are represented by the material points cooperating under the law of universal gravitation. This model remains fair if planet to consider as absolutely rigid spheres with spherical distribution of density. The gravitational potential of such body coincides with potential of a material point, and rotation of each sphere concerning his centre of mass occurs to constant angular velocity. The motion of the centers of mass of spherical planets identically to motion in the appropriate problem of points. Let's notice, that forms of planets of Solar system are close to spherical as dominant forces at formation of planets are gravitational forces to which forces of molecular interaction in substance of a planet counteract. The model of the isolated Solar system submitted in a not indignant condition by homogeneous viscoelastic spheres is considered. Under action of own rotation and tidal gravitational forces the spherical planet changes the shape: there is "flattening" of a planet in a direction of a vector of its angular velocity and formation of tidal bulgs on the lines connecting the centre of a planet with the centers of other planets. From a variational principle of Hamilton the full system of the equations describing movements of the centers of mass of planets, rotations of systems of coordinates, by integrated image connected with planets, and deformations of planets be relative these of systems of coordinates has been obtained. It is supposed, that tidal gravitational, centrifugal and elastic forces result in small change of the spherical form of a planet. In system there are small parameters - inversely proportional of the Young modules of materials of the planets, providing small deformations of planets at influence on them of the centrifugal forces produced by own rotation of planets, and the small tidal deformations arising under influence of gradients of gravitational forces. The method of division of movements

  16. Corn-soybean rotation systems in the Mississippi Delta, implications on mycotoxin contamination and soil populations of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In many crop production systems corn (Zea mays L.) is followed by soybean (Glycine max L. Merr.), however the implication of this rotation on mycotoxin contamination has not been fully evaluated. A four-year field experiment was initiated in 2005 to determine the effects of eight corn– soybean rotat...

  17. Implications of rotational kinematics for the oculomotor system in three dimensions.

    PubMed

    Tweed, D; Vilis, T

    1987-10-01

    1. This paper develops three-dimensional models for the vestibuloocular reflex (VOR) and the internal feedback loop of the saccadic system. The models differ qualitatively from previous, one-dimensional versions, because the commutative algebra used in previous models does not apply to the three-dimensional rotations of the eye. 2. The hypothesis that eye position signals are generated by an eye velocity integrator in the indirect path of the VOR must be rejected because in three dimensions the integral of angular velocity does not specify angular position. Computer simulations using eye velocity integrators show large, cumulative gaze errors and post-VOR drift. We describe a simple velocity to position transformation that works in three dimensions. 3. In the feedback control of saccades, eye position error is not the vector difference between actual and desired eye positions. Subtractive feedback models must continuously adjust the axis of rotation throughout a saccade, and they generate meandering, dysmetric gaze saccades. We describe a multiplicative feedback system that solves these problems and generates fixed-axis saccades that accord with Listing's law. 4. We show that Listing's law requires that most saccades have their axes out of Listing's plane. A corollary is that if three pools of short-lead burst neurons code the eye velocity command during saccades, the three pools are not yoked, but function independently during visually triggered saccades. 5. In our three-dimensional models, we represent eye position using four-component rotational operators called quaternions. This is not the only algebraic system for describing rotations, but it is the one that best fits the needs of the oculomotor system, and it yields much simpler models than do rotation matrix or other representations. 6. Quaternion models predict that eye position is represented on four channels in the oculomotor system: three for the vector components of eye position and one inversely

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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). PMID:25835649

  6. 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.

  7. History Dependence of the Vortex Lattice Rotation in the B-phase of UPt3 with H ∥ c

    NASA Astrophysics Data System (ADS)

    Avers, K. E.; Eskildsen, M. R.; Halperin, W. P.; Gannon, W. J.; Gavilano, J. L.; Nagy, G.; Gasser, U.

    The unconventional superconductor UPt3 is widely believed to be a triplet superconductor, where the low temperature superconducting B-phase is a chiral state. We have performed small angle neutron scattering (SANS) from the vortex lattice (VL) in UPt3 at the Paul Scherrer Institute with the magnetic field parallel to the hexagonal c-axis in the 0.5 T to 0.9 T range. The diffraction pattern of the VL rotates away from a high symmetry direction producing two domains of different orientation. Our field dependent measurements show a subtle magnetic field history dependence of this orientation; VLs prepared with the magnetic field parallel or anti-parallel with respect to the angular momentum from the circulating screening currents show different field-history dependence. These results suggest a coupling of a chiral superconducting order parameter with the applied magnetic field. US DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Awards DE-FG02-10ER46783 (University of Notre Dame; neutron scattering) and DE-FG02-05ER46248 (Northwestern University; crystal growth, characterization, neutron.

  8. Single-frequency pulsed Brillouin-thulium fiber laser at 2 µm with nonlinear polarization rotation and active phase modulation

    NASA Astrophysics Data System (ADS)

    Wang, Xiong; Lv, Haibin; Zhou, Pu; Wu, Weijun; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-10-01

    We present a single-frequency (SF) pulsed fiber laser at 2 µm based on stimulated Brillouin scattering in a thulium-doped fiber laser. The effective feedback of the fiber laser is quite weak to induce pulse operation. Nonlinear polarization rotation and active phase modulation are employed to compress the pulse width and stabilize the pulse train. This SF pulsed Brillouin-thulium fiber laser (BTFL) can generate a stable pulse train with a repetition rate of ˜310 kHz and a pulse width of ˜200 ns. The repetition rate of the pulse train can be adjusted by controlling the cavity length, and the pulse width can be tuned between 200 and 500 ns. The central wavelength locates at 1971.58 nm with an optical signal-to-noise ratio of more than 40 dB, and the linewidth is about 6 MHz. This is the first demonstration of the SF pulsed BTFL as far as we know.

  9. Image-based tracking system for vibration measurement of a rotating object using a laser scanning vibrometer

    NASA Astrophysics Data System (ADS)

    Kim, Dongkyu; Khalil, Hossam; Jo, Youngjoon; Park, Kyihwan

    2016-06-01

    An image-based tracking system using laser scanning vibrometer is developed for vibration measurement of a rotating object. The proposed system unlike a conventional one can be used where the position or velocity sensor such as an encoder cannot be attached to an object. An image processing algorithm is introduced to detect a landmark and laser beam based on their colors. Then, through using feedback control system, the laser beam can track a rotating object.

  10. 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.

  11. 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

  12. Research on phase locked loop in optical memory servo system

    NASA Astrophysics Data System (ADS)

    Qin, Liqin; Ma, Jianshe; Zhang, Jianyong; Pan, Longfa; Deng, Ming

    2005-09-01

    Phase locked loop (PLL) is a closed loop automatic control system, which can track the phase of input signal. It widely applies in each area of electronic technology. This paper research the phase locked loop in optical memory servo area. This paper introduces the configuration of digital phase locked loop (PLL) and phase locked servo system, the control theory, and analyses system's stability. It constructs the phase locked loop experiment system of optical disk spindle servo, which based on special chip. DC motor is main object, this system adopted phase locked servo technique and digital signal processor (DSP) to achieve constant linear velocity (CLV) in controlling optical spindle motor. This paper analyses the factors that affect the stability of phase locked loop in spindle servo system, and discusses the affection to the optical disk readout signal and jitter due to the stability of phase locked loop.

  13. 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

  14. 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.

  15. Interferometric rotation sensor

    NASA Technical Reports Server (NTRS)

    Walsh, T. M. (Inventor)

    1973-01-01

    An interferometric rotation sensor and control system is provided which includes a compound prism interferometer and an associated direction control system. Light entering the interferometer is split into two paths with the light in the respective paths being reflected an unequal number of times, and then being recombined at an exit aperture in phase differing relationships. Incoming light is deviated from the optical axis of the device by an angle, alpha. The angle causes a similar displacement of the two component images at the exit aperture which results in a fringe pattern. Fringe numbers are directly related to angle alpha. Various control systems of the interferometer are given.

  16. 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.

  17. Reduction of nonlinear phase noise using optical phase conjugation in quasi-linear optical transmission systems.

    PubMed

    Kumar, Shiva; Liu, Ling

    2007-03-01

    An analytical expression for the variance of nonlinear phase noise for a quasi-linear system using the midpoint optical phase conjugation (OPC) is obtained. It is shown that the the system with OPC and dispersion inversion (DI) can exactly cancel the nonlinear phase noise up to the first order in nonlinear coefficient if the amplifier and the end point of the system are equidistant from the OPC. It is found that the nonlinear phase noise variance of the midpoint phase-conjugated optical transmission system with DI is smaller than that of the system without DI. PMID:19532453

  18. 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

  19. A review on prognostic techniques for non-stationary and non-linear rotating systems

    NASA Astrophysics Data System (ADS)

    Kan, Man Shan; Tan, Andy C. C.; Mathew, Joseph

    2015-10-01

    The field of prognostics has attracted significant interest from the research community in recent times. Prognostics enables the prediction of failures in machines resulting in benefits to plant operators such as shorter downtimes, higher operation reliability, reduced operations and maintenance cost, and more effective maintenance and logistics planning. Prognostic systems have been successfully deployed for the monitoring of relatively simple rotating machines. However, machines and associated systems today are increasingly complex. As such, there is an urgent need to develop prognostic techniques for such complex systems operating in the real world. This review paper focuses on prognostic techniques that can be applied to rotating machinery operating under non-linear and non-stationary conditions. The general concept of these techniques, the pros and cons of applying these methods, as well as their applications in the research field are discussed. Finally, the opportunities and challenges in implementing prognostic systems and developing effective techniques for monitoring machines operating under non-stationary and non-linear conditions are also discussed.

  20. Development of a photogrammetry system for the measurement of rotationally symmetric forgings

    NASA Astrophysics Data System (ADS)

    Zatočilová, Aneta; Paloušek, David; Brandejs, Jan

    2015-05-01

    The paper presents the development of a system for the measurement of the shapes and dimensions of rotationally symmetric forgings under high temperature. These large semi-finished products are measured with demands for accuracy on the order of millimeters. The challenge is to design a measurement system that overcomes the problems caused by high temperature and provides results instantly without interrupting the production process. The proposed approach exploits the fact, that the measured parts have simple rotationally symmetric shape. It is based on the assumption that (in the simplest case) the actual shape can be determined from four boundary curves which lie in two mutually perpendicular planes. These four boundary curves can be obtained by determining the edges of the forging in two images. The proposed approach has been incorporated into a software application created in Matlab programming environment. Hence the system does not use added illumination resolving edge detection and scale calculation is a crucial step. The main parts of the system, such as calibration, edge detection, spatial orientation, and the evaluation of information about the shapes and dimensions of the measured parts, have been designed so that the entire measurement process takes only a few seconds. The article focuses on the individual parts of the software application. It discusses the suitability of using particular mathematical models and the designed multi-step edge detection method, which is based on thresholding, directional median filtering and validation and correction of detected edge points.

  1. Sensitivity of tropical stratospheric ozone to rotational UV variations estimated from UARS and Aura MLS observations during the declining phases of solar cycles 22 and 23

    NASA Astrophysics Data System (ADS)

    Bossay, Sébastien; Bekki, Slimane; Marchand, Marion; Poulain, Virginie; Toumi, Ralf

    2015-08-01

    The correlation between tropical stratospheric ozone and UV radiation on solar rotational time scales is investigated using daily satellite ozone observations and reconstructed solar spectra. We consider two 3-year periods falling within the descending phases of two 11-year solar cycles 22 (1991-1994) and 23 (2004-2007). The UV rotational cycle is highly irregular and even disappears for half a year during cycle 23. For the 1991-1994 period, ozone and 205 nm UV flux are found to be correlated between about 10 and 1 hPa with a maximum of 0.29 at ~5 hPa; ozone sensitivity (percentage change in ozone for 1% change in UV) peaks at ~0.4. Correlation during cycle 23 is weaker with a peak ozone sensitivity of 0.2. The correlation is found to vary widely, not only with altitude, but also from one year to the next with a rotational signal in ozone appearing almost intermittent. Unexpectedly, the correlation is not found to bear any relation with the solar rotational forcing. For instance, solar rotational fluctuations are by far the strongest during 1991-1992 whereas the correlation peaks at the end of 1993, a rotationally quiescent period. When calculated over sliding intervals of 1-year, the sensitivity is found to vary very strongly within both 3-year periods; it is almost negligible over the entire vertical profile during some 1-year intervals or reaches close to 1 around 2-5 mb for other intervals. Other sources of variability, presumably of dynamical origin, operate on the rotational spectral range and determine to a large extent the estimated solar rotational signal. Even considering 3 years of observations (corresponding to about 40 solar cycles), the extraction of the rotational solar signal does not appear to be robust during declining phases of 11-year solar cycles. As observational studies cover at best three 11-year solar cycles, it must be challenging to produce a reliable estimation of the 11-year solar cycle signal in stratospheric ozone, especially in the

  2. 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.

  3. 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

  4. Phase and amplitude control in the formation and detection of rotational wave packets in the E 1Σg+ state of Li2

    NASA Astrophysics Data System (ADS)

    Uberna, Radoslaw; Khalil, Munira; Williams, Richard M.; Papanikolas, John M.; Leone, Stephen R.

    1998-06-01

    Femtosecond laser pulse amplitude/phase masking techniques are employed to control the formation and detection of rotational wave packets in the electronic E 1Σg+ state of lithium dimer. The wave packets are prepared by coherent excitation of rovibronic E 1Σg+(νE,JE) states of Li2 from a single intermediate state, A 1Σu+(νA=11,JA=28), and probed by time-resolved photoionization. In the detection step, the wave packet is projected onto the X 2Σg+ state of Li2+. New resonance structure in the X 2Σu+ ionic state continuum is obtained by measuring the wave packet signal modulation amplitude as a function of the frequencies removed from the spectrally dispersed probe pulse by insertion of a wire mask in a single-grating pulse shaper. A split glass phase mask inserted into the pulse shaper is used to produce step function changes in the spectral phase of the pulse. The phase relation among the wave packet states is varied by changing the relative phases of spectral components in the pump pulse and is monitored by measuring the changes in the phase of the rotational wave packet recurrences using an unmodified probe pulse. By altering the relative phases among the wave packet components, the spatial distribution of the initial wave packet probability density is varied, resulting in phase-dependent "alignment" of the probability density in angular space. Phase changes in the signal recurrences are also observed when a phase modified pulse is used in the wave packet detection step after wave packet preparation with an unmodified pulse. The formation and detection of the wave packets is discussed in terms of quantum interference between different excitation routes. The relative phase factors encoded in a single optical pulse (pump or probe) are transferred into the interference term of the measured signal through the molecule-photon interaction.

  5. Method and system for controlling a rotational speed of a rotor of a turbogenerator

    DOEpatents

    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.

  6. 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.

  7. Crop Rotation and Straw Residue Effects on Soil Carbon In Three Grass Seed Cropping Systems Of Western Oregon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As grass seed crop field burning in western Oregon was phased-out, alternative non-thermal practices, such as post harvest straw residue removal or incorporation to the soil, and crop rotations were being developed. There is little information available on the practicality and impacts of non-thermal...

  8. Operation of the counter-rotating type pump-turbine unit installed in the power stabilizing system

    NASA Astrophysics Data System (ADS)

    Kanemoto, T.; Honda, H.; Kasahara, R.; Miyaji, T.

    2014-03-01

    This serial research intends to put a unique power stabilization system with a pumped storage into practical use. The pumped storage is equipped with a counter-rotating type pump-turbine unit whose operating mode can be shifted instantaneously in response to the fluctuation of power from renewable resources. This paper verifies that the system is reasonably effective to stabilize the fluctuating power. It is necessary to quickly increase the rotational speed when the operation is shifted from the turbine to the pumping modes, because the unit cannot pump-up water from a lower reservoir at a slow rotational speed while keeping gross/geodetic head constant. The maximum hydraulic efficiency at the turbine mode is close to the efficiency of the counter-rotating type hydroelectric unit designed exclusively for the turbine mode. The system is also provided for a pilot plant to be operated in the field.

  9. Separation of aqueous two-phase polymer systems in microgravity

    NASA Technical Reports Server (NTRS)

    Vanalstine, J. M.; Harris, J. M.; Synder, S.; Curreri, P. A.; Bamberger, S. B.; Brooks, D. E.

    1984-01-01

    Phase separation of polymer systems in microgravity is studied in aircraft flights to prepare shuttle experiments. Short duration (20 sec) experiments demonstrate that phase separation proceeds rapidly in low gravity despite appreciable phase viscosities and low liquid interfacial tensions (i.e., 50 cP, 10 micro N/m). Ostwald ripening does not appear to be a satisfactory model for the phase separation mechanism. Polymer coated surfaces are evaluated as a means to localize phases separated in low gravity. Contact angle measurements demonstrate that covalently coupling dextran or PEG to glass drastically alters the 1-g wall wetting behavior of the phases in dextran-PEG two phase systems.

  10. 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.

  11. Re-entrant phase behavior for systems with competition between phase separation and self-assembly

    NASA Astrophysics Data System (ADS)

    Reinhardt, Aleks; Williamson, Alexander J.; Doye, Jonathan P. K.; Carrete, Jesús; Varela, Luis M.; Louis, Ard A.

    2011-03-01

    In patchy particle systems where there is a competition between the self-assembly of finite clusters and liquid-vapor phase separation, re-entrant phase behavior can be observed, with the system passing from a monomeric vapor phase to a region of liquid-vapor phase coexistence and then to a vapor phase of clusters as the temperature is decreased at constant density. Here, we present a classical statistical mechanical approach to the determination of the complete phase diagram of such a system. We model the system as a van der Waals fluid, but one where the monomers can assemble into monodisperse clusters that have no attractive interactions with any of the other species. The resulting phase diagrams show a clear region of re-entrance. However, for the most physically reasonable parameter values of the model, this behavior is restricted to a certain range of density, with phase separation still persisting at high densities.

  12. 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.

  13. 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.

  14. Enhancement of phase-conjugate reflectivity using Zeeman coherence in highly degenerate molecular systems

    SciTech Connect

    Mukherjee, Nandini

    2010-01-15

    A comprehensive theoretical analysis is developed for the vectorial phase conjugation using resonant four-wave mixing (FWM) in a highly degenerate rotational vibrational molecular system. The dynamic Stark shifts, saturation, and Doppler broadening are included for a realistic analysis. It is shown that the electromagnetically induced multilevel coherence controls the nonlinear wave mixing yielding interesting results for the phase conjugate (PC) reflectivity. It turns out that the efficiency of the PC reflectivity is decided by the relative phase of the Zeeman coherence and the population grating. When these two contributions are aligned in phase by a small detuning of the pump frequency, a large PC reflectivity (approx20%) is obtained with moderate pump intensity (approx500 mW/cm{sup 2}).

  15. 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

  16. Collective dynamics of rotating colloidal particles

    NASA Astrophysics Data System (ADS)

    Magkiriadou, Sofia; Soni, Vishal; van Zuiden, Benny; Bartolo, Denis; Vitelli, Vincenzo; Irvine, William T. M.

    We study magnetic colloidal particles in suspension under the influence of a rotating magnetic field. When in aggregates, these particles show rich dynamics that are governed by magnetic and hydrodynamic interactions. By tuning these interactions, we probe the phase diagram of this system and study the emergent collective dynamics. Finally, we begin to investigate whether we can control this phase diagram with geometry.

  17. 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

  18. Faraday rotators for use in multijoule Nd:Cr:GSGG and Nd:glass, phase and polarization conjugated multiple-pass amplifiers

    NASA Astrophysics Data System (ADS)

    Jackel, Steven M.; Moshe, Inon; Kaufman, Alon; Lavi, Raphael; Lallouz, Raphael; Jackel, Z.

    1997-09-01

    High fluence solid-state lasers were built using Nd:Cr:GSGG or Nd:glass in oscillator/multiple-pass phase and polarization conjugated amplifier configurations. Beam path control, thermal stress induced birefringence correction, and isolation were achieved using Faraday rotators. Damage threshold on material and on pulse duration were investigated. Terbium glass was found to have a damage threshold five times greater than that of TGG. The damage threshold of both Terbium doped materials was virtually independent of pulse duration.

  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. Transition of Bery Phase and Pancharatnam Phase and Phase Change

    NASA Astrophysics Data System (ADS)

    Fu, Guolan; Pan, Hui; Wang, Zisheng

    2016-07-01

    Berry Phase and time-dependent Pancharatnam phase are investigated for nuclear spin polarization in a liquid by a rotation magnetic field, where two-state mixture effect is exactly included in the geometric phases. We find that when the system of nuclear spin polarization is in the unpolarized state, the transitive phenomena of both Berry phase and Pancharatnam phase are taken place. For the polarized system, in contrast, such a transition is not taken place. It is obvious that the transitions of geometric phase correspond to the phase change of physical system.

  1. 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.

  2. 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…

  3. 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.

  4. 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

  5. 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.

  6. Solid phases in electro- and magnetorheological systems

    NASA Astrophysics Data System (ADS)

    Brandt, Philip C.; Ivlev, Alexei V.; Morfill, Gregor E.

    2009-05-01

    Ensembles of particles with a spherically symmetric repulsive Yukawa interaction and additional dipole-dipole interaction induced by an external field exhibit numerous solid-solid phase transitions controlled by the magnitude of the field. Such interactions emerge most notably in electro- and magnetorheological fluids and plasmas. We propose a simple variational approach based on the Bogoliubov inequality for determining equilibrium solid phases. Phase diagrams for several regimes are calculated and compared with previously performed Monte Carlo and molecular dynamics simulations.

  7. 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.

  8. 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.

  9. Adaptive optimisation of a generalised phase contrast beam shaping system

    NASA Astrophysics Data System (ADS)

    Kenny, F.; Choi, F. S.; Glückstad, J.; Booth, M. J.

    2015-05-01

    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.

  10. System For Characterizing Three-Phase Brushless dc Motors

    NASA Technical Reports Server (NTRS)

    Howard, David E.; Smith, Dennis A.

    1996-01-01

    System of electronic hardware and software developed to automate measurements and calculations needed to characterize electromechanical performances of three-phase brushless dc motors, associated shaft-angle sensors needed for commutation, and associated brushless tachometers. System quickly takes measurements on all three phases of motor, tachometer, and shaft-angle sensor simultaneously and processes measurements into performance data. Also useful in development and testing of motors with not only three phases but also two, four, or more phases.

  11. Multiwavelength Observations of Two Moderate Rotation RS CVn Systems: V815 Herculis and IM Pegasi

    NASA Astrophysics Data System (ADS)

    Dempsey, Robert C.; Neff, James E.; O'Neal, Douglas; Olah, Katalin

    1996-03-01

    Near-to-simultaneous ultraviolet and visual spectroscopy of two moderate v sin i RS CVn systems, V815 Herculis (v sin i=27 km s-1) and IM Pegasi (v sin i=24 km s-1), are presented along with contemporaneous UBV(RI)c photometry. These data were used to probe inhomogeneities in the chromospheres and photospheres, and the possible relationship between them. Variability is observed at all wavelengths, some indicators showing rotationally modulated fluctuations. We use UBVRI photometry and TiO spectra to estimate temperatures, area, and locations of photospheric spots on IM Peg. Evidence is presented that the spot temperature in IM Peg has changed over a possible solar-like spot cycle. Radial velocities of V815 Her indicates that the system is actually triple.

  12. Rotational-translational fourier imaging system requiring only one grid pair

    NASA Technical Reports Server (NTRS)

    Campbell, Jonathan W. (Inventor)

    2006-01-01

    The sky contains many active sources that emit X-rays, gamma rays, and neutrons. Unfortunately hard X-rays, gamma rays, and neutrons cannot be imaged by conventional optics. This obstacle led to the development of Fourier imaging systems. In early approaches, multiple grid pairs were necessary in order to create rudimentary Fourier imaging systems. At least one set of grid pairs was required to provide multiple real components of a Fourier derived image, and another set was required to provide multiple imaginary components of the image. It has long been recognized that the expense associated with the physical production of the numerous grid pairs required for Fourier imaging was a drawback. Herein one grid pair (two grids), with accompanying rotation and translation, can be used if one grid has one more slit than the other grid, and if the detector is modified.

  13. 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.

  14. 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.

  15. Studies on aqueous two phase polymer systems useful for partitioning of biological materials

    NASA Technical Reports Server (NTRS)

    Brooks, D. E.; Bamberger, S.

    1982-01-01

    The two phase systems that result when aqueous solutions of dextran and poly(ethylene glycol) (PEG) are mixed above a critical concentration of a few percent provide a useful medium for the separation of biological cell subpopulations via partition between the top, PEG-rich phase and the liquid-liquid phase boundary. Interfacial tensions of such systems have been measured by the rotating drop technique and found to range between 0.1-100 micro-N/m. The tension was found to depend on the length of the tie line describing the system on a phase diagram, via a power law relationship which differed depending on the concentration of Na phosphate buffer present. The electrokinetic properties of drops of one phase suspended in the other were studied for a variety of systems. It was found that the droplet electrophoretic mobility increased monotonically with phosphate concentration and drop diameter but exhibited the opposite sign from that anticipated from phosphate partition measurements. It was possible to take advantage of these electrokinetic properties and dramatically enhance the speed of phase separation through application of relatively small electric fields.

  16. 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.

  17. Ground and Low-Lying Collective States of Rotating Three-Boson System

    NASA Astrophysics Data System (ADS)

    Imran, Mohd.; Ahsan, M. A. H.

    2016-04-01

    The ground and low-lying collective states of a rotating system of N = 3 bosons harmonically confined in quasi-two-dimension and interacting via repulsive finite-range Gaussian potential is studied in weakly to moderately interacting regime. The N-body Hamiltonian matrix is diagonalized in subspaces of quantized total angular momenta 0 ≥ L ≥ 4N to obtain the ground and low-lying eigenstates. Our numerical results show that breathing modes with N-body eigenenergy spacing of 2ħω⊥, known to exist in strictly 2D system with zero-range (δ-function) interaction potential, may as well exist in quasi-2D system with finite-range Gaussian interaction potential. To gain an insight into the many-body states, the von Neumann entropy is calculated as a measure of quantum correlation and the conditional probability distribution is analyzed for the internal structure of the eigenstates. In the rapidly rotating regime the ground state in angular momentum subspaces L = (q/2)N (N ‑ 1) with q = 2, 4 is found to exhibit the anticorrelation structure suggesting that it may variationally be described by a Bose-Laughlin like state. We further observe that the first breathing mode exhibits features similar to the Bose-Laughlin state in having eigenenergy, von Neumann entropy and internal structure independent of interaction for the three-boson system considered here. On the contrary, for eigenstates lying between the Bose-Laughlin like ground state and the first breathing mode, values of eigenenergy, von Neumann entropy and internal structure are found to vary with interaction.

  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. Mössbauer experiments in a rotating system: Recent errors and novel interpretation

    NASA Astrophysics Data System (ADS)

    Yarman, T.; Kholmetskii, A. L.; Arik, M.

    2015-10-01

    We consider the energy shift between emission and absorption lines in the Mössbauer experiments in a rotating system in the view of a recently reported extra component of such a shift, in addition to the usual relativistic time dilation effect, expressed by the inequality k > 0.5 in the expression for the relative energy shift ΔE/ E = - ku 2/ c 2 ( u is the orbital velocity, and c the light velocity in vacuum). We consider the recent attempts of re-interpretation of the Mössbauer rotor experiments, showing their incorrectness, and analyze the proposed explanations of the physical origin of this extra energy shift. This way we stress that the energy of nuclei located in crystal cells should be determined via relativistic quantum mechanics, involving the geometry of a rotating disc. We show that the standard theory yields k = 1/2; applying the YARK gravitational theory, we obtain k = 2/3 in a perfect agreement with experimental data.

  20. A new extended diffusion model for rotational motion of symmetric-top molecules in the liquid phase

    NASA Astrophysics Data System (ADS)

    Lascombe, J.; Besnard, M.; Maraval, P.

    1982-11-01

    In this paper, we present first a model called partially relaxed rotation model (PRR), to treat the reorientation motion of a symmetric top which rotates freely around its molecular axis with a tumbling motion relaxed according to a characteristic time τ 1. We show that this model can easily be extended to develop a 2τ model where both tumbling and spinning motion around the molecular axis are relaxed with a second characteristic time τ 2. As limiting cases one can obtain from the 2τ model, the Gordon-McClung and PRR models. Next, we illustrate the PPR and 2τ models by calculating Raman and infrared rotational spectral densities of liquid cyclopropane at room temperature. We also discuss in the PRR model the influence of the characteristic relaxation time τ 1, on the Raman rotational profile Î21( overlineν) Finally, we emphasize on the example of room-temperature liquid cyclopropane, the advantage of the PRR model to treat a E″ degenerated Raman profile with negligible Coriolis vibrational-rotational interaction. bl

  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-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

  3. 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.

  4. 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.

  5. Hidden attractor and homoclinic orbit in Lorenz-like system describing convective fluid motion in rotating cavity

    NASA Astrophysics Data System (ADS)

    Leonov, G. A.; Kuznetsov, N. V.; Mokaev, T. N.

    2015-11-01

    In this paper a Lorenz-like system, describing convective fluid motion in rotating cavity, is considered. It is shown numerically that this system, like the classical Lorenz system, possesses a homoclinic trajectory and a chaotic self-excited attractor. However, for the considered system, unlike the classical Lorenz system, along with self-excited attractor a hidden attractor can be localized. Analytical-numerical localization of hidden attractor is demonstrated.

  6. 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.

  7. 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.

  8. AC field measurements of Fermilab Booster correctors using a rotating coil system

    SciTech Connect

    Velev, G.V.; DiMarco, J.; Harding, D.J.; Kashikhin, V.; Lamm, M.; Makulski, A.; Orris, D.; Schlabach, P.; Sylvester, C.; Tartaglia, M.; Tompkins, J.; /Fermilab

    2006-07-01

    The first prototype of a new corrector package for the Fermilab Booster Synchrotron is presently in production. This water-cooled package includes normal and skew dipole, quadrupole and sextupole elements to control orbit, tune and chromaticity of the beam over the full range of Booster energies (0.4-8 GeV). These correctors operate at the 15 Hz excitation cycle of the main synchrotron magnets, but must also make more rapid excursions, in some cases even switching polarity in approximately 1 ms at transition crossing. To measure the dynamic field changes during operation, a new method based on a relatively slow rotating coil system is proposed. The method pieces together the measured voltages from successive current cycles to reconstruct the field harmonics. This paper describes the method and presents initial field quality measurements from a Tevatron corrector.

  9. Optomechanical design of near-null subaperture test system based on counter-rotating CGH plates

    NASA Astrophysics Data System (ADS)

    Li, Yepeng; Chen, Shanyong; Song, Bing; Li, Shengyi

    2014-09-01

    In off-axis subapertures of most convex aspheres, astigmatism and coma dominate the aberrations with approximately quadratic and linear increase as the off-axis distance increases. A pair of counter-rotating computer generated hologram (CGH) plates is proposed to generate variable amount of Zernike terms Z4 and Z6, correcting most of the astigmatism and coma for subapertures located at different positions on surfaces of various aspheric shapes. The residual subaperture aberrations are then reduced within the vertical range of measurement of the interferometer, which enables near-null test of aspheres flexibly. The alignment tolerances for the near-null optics are given with optomechanical analysis. Accordingly a novel design for mounting and aligning the CGH plates is proposed which employs three concentric rigid rings. The CGH plate is mounted in the inner ring which is supported by two couples of ball-end screws in connection with the middle ring. The CGH plate along with the inner ring is hence able to be translated in X-axis and tipped by adjusting the screws. Similarly the middle ring is able to be translated in Y-axis and tilted by another two couples of screws orthogonally arranged and connected to the outer ring. This design is featured by the large center-through hole, compact size and capability of four degrees-of-freedom alignment (lateral shift and tip-tilt). It reduces the height measured in the direction of optical axis as much as possible, which is particularly advantageous for near-null test of convex aspheres. The CGH mounts are then mounted on a pair of center-through tables realizing counter-rotation. Alignment of the interferometer, the CGHs, the tables and the test surface is also discussed with a reasonable layout of the whole test system. The interferometer and the near-null optics are translated by a three-axis stage while the test mirror is rotated and tilted by two rotary tables. Experimental results are finally given to show the near

  10. 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.

  11. 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...

  12. 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...

  13. 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...

  14. 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.

  15. Carrier envelope phase noise in stabilized amplifier systems.

    PubMed

    Gohle, Christoph; Rauschenberger, Jens; Fuji, Takao; Udem, Thomas; Apolonski, Alexander; Krausz, Ferenc; Hänsch, Theodor W

    2005-09-15

    At present most laser systems for generating phase-stabilized high-energy pulses are chirped pulse amplifier systems that involve the selection and subsequent amplification of pulses from a phase-stabilized seed oscillator. We investigate the effect of the picking process on the carrier envelope phase stability and how the phase noise of the picked pulse sequence can be estimated from the phase noise properties of the seed oscillator. All noise components from the original pulse train above the picking frequency are aliased into the picked pulse train and therefore cannot be neglected. PMID:16196361

  16. 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).

  17. 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.

  18. Performance of an in-situ rotating biological contactor in a recirculating aquaculture system.

    PubMed

    Marin, P; Donoso-Bravo, A; Campos, J L; Ruiz-Filippi, G; Chamy, R

    2011-01-01

    The start-up and activation of a nitrifying rotating biological contactor (RBC) and its performance inside a culture tank of rainbow trout were studied. First, in a lab-scale operation, the system was fed with a synthetic medium containing a high ammonia concentration (567 mg NH(4)(+)-N L(-1)) and operated at a high hydraulic retention time (HRT) (6.5 days) to minimize the wash-out of the biomass and promote the biofilm formation. Then, both inlet ammonia concentration and HRT were decreased in order to obtain operational conditions similar to those of the culture tank. During this period, the RBC was able to treat an ammonia loading rate (ALR) of 0.64 g N-NH(4)(+) L(-1) d(-1) with a removal efficiency within 70-100%. Pilot-scale experiments were carried out in culture tanks of rainbow trout. The operation of a recirculating system with the RBC unit was compared with a recirculating system without biological treatment and with a flow-through system. The use of this in-situ nitrifying unit allowed working at a recirculation ratio of 90% without negative effects on either growth or the condition factor of fishes. Up to 70% of ammonia generated was removed and a removal rate of 1.41 g NH(4)(+)-N m(-2) d(-1) was reached. PMID:22156125

  19. Negative initial phase shift of Kerr rotation generated from the building-up process of resident electron spin polarization in a CdTe single quantum well

    NASA Astrophysics Data System (ADS)

    Yan, L.-P.; Kurosawa, M.; Kaji, R.; Karczewski, G.; Takeyama, S.; Adachi, S.

    2014-11-01

    Initial phase shift in a precessional motion of resident electron-spin polarization is studied in a CdTe/Cd 0.85Mg0.15Te single quantum well using a time-resolved Kerr rotation technique. The generation dynamics of resident electron-spin polarization involve the formation and transformation of the associated optically excited states and are complicated particularly in the early time region. A careful analysis of the phase shift gives a deep understanding of the generation processes. In the experiments, the negative phase shift of the resident electron-spin polarization is observed, and the mechanism associated especially with a quick hole spin flip in negative trions is studied through the dependences on excitation power and magnetic field strength.

  20. Assessment of soil biological quality index (QBS-ar) in different crop rotation systems in paddy soils

    NASA Astrophysics Data System (ADS)

    Nadimi-Goki, Mandana; Bini, Claudio; haefele, Stephan

    2013-04-01

    New methods, based on soil microarthropods for soil quality evaluation have been proposed by some Authors. Soil microarthropods demonstrated to respond sensitively to land management practices and to be correlated with beneficial soil functions. QBS Index (QBS-ar) is calculated on the basis of microarthropod groups present in a soil sample. Each biological form found in the sample receives a score from 1 to 20 (eco-morphological index, EMI), according to its adaptation to soil environment. The objective of this study was to evaluate the effect of various rotation systems and sampling periods on soil biological quality index, in paddy soils. For the purpose of this study surface soil samples (0-15 cm depth) were collected from different rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) with three replications, and four sampling times in April (after field preparation), June (after seedling), August (after tillering stage) and October (after rice harvesting). The study area is located in paddy soils of Verona area, Northern Italy. Soil microarthropods from a total of 48 samples were extracted and classified according to the Biological Quality of Soil Index (QBS-ar) method. In addition soil moisture, Cumulative Soil Respiration and pH were measured in each site. More diversity of microarthropod groups was found in June and August sampling times. T-test results between different rotations did not show significant differences while the mean difference between rotation and different sampling times is statistically different. The highest QBS-ar value was found in the fallow-rice rotation in the forth soil sampling time. Similar value was found in soya-rice-rice rotation. Result of linear regression analysis indicated that there is significant correlation between QBS-ar values and Cumulative Soil Respiration. Keywords: soil biological quality index (QBS-ar), Crop Rotation System, paddy soils, Italy

  1. Symmetric rotating-wave approximation for the generalized single-mode spin-boson system

    SciTech Connect

    Albert, Victor V.; Scholes, Gregory D.; Brumer, Paul

    2011-10-15

    The single-mode spin-boson model exhibits behavior not included in the rotating-wave approximation (RWA) in the ultra and deep-strong coupling regimes, where counter-rotating contributions become important. We introduce a symmetric rotating-wave approximation that treats rotating and counter-rotating terms equally, preserves the invariances of the Hamiltonian with respect to its parameters, and reproduces several qualitative features of the spin-boson spectrum not present in the original rotating-wave approximation both off-resonance and at deep-strong coupling. The symmetric rotating-wave approximation allows for the treatment of certain ultra- and deep-strong coupling regimes with similar accuracy and mathematical simplicity as does the RWA in the weak-coupling regime. Additionally, we symmetrize the generalized form of the rotating-wave approximation to obtain the same qualitative correspondence with the addition of improved quantitative agreement with the exact numerical results. The method is readily extended to higher accuracy if needed. Finally, we introduce the two-photon parity operator for the two-photon Rabi Hamiltonian and obtain its generalized symmetric rotating-wave approximation. The existence of this operator reveals a parity symmetry similar to that in the Rabi Hamiltonian as well as another symmetry that is unique to the two-photon case, providing insight into the mathematical structure of the two-photon spectrum, significantly simplifying the numerics, and revealing some interesting dynamical properties.

  2. Phase ordering in disordered and inhomogeneous systems.

    PubMed

    Corberi, Federico; Zannetti, Marco; Lippiello, Eugenio; Burioni, Raffaella; Vezzani, Alessandro

    2015-06-01

    We study numerically the coarsening dynamics of the Ising model on a regular lattice with random bonds and on deterministic fractal substrates. We propose a unifying interpretation of the phase-ordering processes based on two classes of dynamical behaviors characterized by different growth laws of the ordered domain size, namely logarithmic or power law, respectively. It is conjectured that the interplay between these dynamical classes is regulated by the same topological feature that governs the presence or the absence of a finite-temperature phase transition. PMID:26172676

  3. Phase ordering in disordered and inhomogeneous systems

    NASA Astrophysics Data System (ADS)

    Corberi, Federico; Zannetti, Marco; Lippiello, Eugenio; Burioni, Raffaella; Vezzani, Alessandro

    2015-06-01

    We study numerically the coarsening dynamics of the Ising model on a regular lattice with random bonds and on deterministic fractal substrates. We propose a unifying interpretation of the phase-ordering processes based on two classes of dynamical behaviors characterized by different growth laws of the ordered domain size, namely logarithmic or power law, respectively. It is conjectured that the interplay between these dynamical classes is regulated by the same topological feature that governs the presence or the absence of a finite-temperature phase transition.

  4. 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.

  5. 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.

  6. 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.

  7. Phase compensation with fiber optic surface profile acquisition and reconstruction system

    NASA Astrophysics Data System (ADS)

    Bo, En; Duan, Fajie; Feng, Fan; Lv, Changrong; Xiao, Fu; Huang, Tingting

    2015-02-01

    A fiber-optic sinusoidal phase modulating (SPM) interferometer was proposed for the acquisition and reconstruction of three-dimensional (3-D) surface profile. Sinusoidal phase modulation was induced by controlling the injection current of light source. The surface profile was constructed on the basis of fringe projection. Fringe patterns are vulnerable to external disturbances such as mechanical vibration and temperature fluctuation, which cause phase drift in the interference signal and decrease measuring accuracy. A closed-loop feedback phase compensation system was built. In the subsystem, the initial phase of the interference signal, which was caused by the initial optical path difference between interference arms, could be demodulated using phase generated carrier (PGC) method and counted out using coordinated rotation digital computer (CORDIC) , then a compensation voltage was generated for the PZT driver. The bias value of external disturbances superimposed on fringe patterns could be reduced to about 50 mrad, and the phase stability for interference fringes was less than 6 mrad. The feasibility for real-time profile measurement has been verified.

  8. 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.

  9. Phase-Discriminating Capacitive Sensor System

    NASA Technical Reports Server (NTRS)

    Vranish, John M.; Rahim, Wadi

    1993-01-01

    Crosstalk eliminated by maintaining voltages on all electrodes at same amplitude, phase, and frequency. Each output feedback-derived control voltage, change of which indicates proximity-induced change in capacitance of associated sensing electrode. Sensors placed close together, enabling imaging of sort. Images and/or output voltages used to guide robots in proximity to various objects.

  10. The Evaluation Phase of Systemic Family Therapy.

    ERIC Educational Resources Information Center

    Caille, Philippe

    1982-01-01

    Describes the initial evaluation phase of family therapy, which clarifies the circular interaction maintaining the symptom, the family structure, and its relationship to the therapist. Suggests using first sessions to collect data and organize it meaningfully. Presents phenomenological and mythical models of family functioning as guides for…

  11. 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

  12. 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.

  13. Zero-distance phase front of an isoplanar optical system

    NASA Astrophysics Data System (ADS)

    Gitin, Andrey

    2016-05-01

    The concept of "the zero-distance phase front" of an isoplanar optical system is used to describe its aberration. It is shown that Walther's wave interpretation of eikonals allows treating "the zero-distance phase front" as the wave aberration function of the optical system and calculating its transverse aberrations.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Hopf bifurcation and multistability in a system of phase oscillators

    NASA Astrophysics Data System (ADS)

    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.

  2. 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. PMID:24125326

  3. Nitrogen, Tillage, and Crop Rotation Effects On Carbon Dioxide and Methane Fluxes from Irrigated Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term effects of tillage intensity, N fertilization, and crop rotation on carbon dioxide (CO2) and methane (CH4) flux from semiarid irrigated soils are poorly understood. We evaluated effects of: a) tillage intensity [no-till (NT) and moldboard plow tillage (CT)] in a continuous corn rotation; b...

  4. 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.

  5. Thermophotovoltaic space power system, phase 3

    NASA Technical Reports Server (NTRS)

    Horne, W. E.; Lancaster, C.

    1987-01-01

    Work performed on a research and development program to establish the feasibility of a solar thermophotovoltaic space power generation concept was summarized. The program was multiphased. The earlier work is summarized and the work on the current phase is detailed as it pertains to and extends the earlier work. Much of the experimental hardware and materials development was performed on the internal program. Experimental measurements and data evaluation were performed on the contracted effort. The objectives of the most recent phase were: to examine the thermal control design in order to optimize it for lightweight and low cost; to examine the concentrator optics in an attempt to relieve pointing accuracy requirements to + or - 2 degrees about the optical axis; and to use the results of the thermal and optical studies to synthesize a solar thermophotovoltaic (STPV) module design that is optimized for space application.

  6. 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.

  7. 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.

  8. 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.

  9. ECOSTATIC CANE PROCESSING SYSTEM PROTOTYPE PHASE

    EPA Science Inventory

    The overall objective of this project was to demonstrate a systems environmental management approach, from field to final product, for the processing of raw cane sugar. Specific sub-systems which were to be developed and demonstrated as part of this systems approach were: (a) har...

  10. 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…

  11. Holographic and weak-phase projection system for 3D shape reconstruction using temporal phase unwrapping

    NASA Astrophysics Data System (ADS)

    González, C. A.; Dávila, A.; Garnica, G.

    2007-09-01

    Two projection systems that use an LCoS phase modulator are proposed for 3D shape reconstruction. The LCoS is used as an holographic system or as a weak phase projector, both configurations project a set of fringe patterns that are processed by the technique known as temporal phase unwrapping. To minimize the influence of camera sampling, and the speckle noise in the projected fringes, an speckle noise reduction technique is applied to the speckle patterns generated by the holographic optical system. Experiments with 3D shape reconstruction of ophthalmic mold and other testing specimens show the viability of the proposed techniques.

  12. 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

  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. 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.

  15. 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.

  16. 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

  17. 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

  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. PMID:25324791

  19. 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.

  20. Microgravity experiments with a simple two-phase thermal system

    SciTech Connect

    Crowley, C.J.; Sam, R.G. )

    1991-01-10

    Microgravity experiments with a simple two-phase thermal system are described. Microgravity experiments aboard the NASA KC-135 aircraft provide variable acceleration 0.01g to 2g, with low gravity for 20 to 25 seconds. The two-phase loop allows the vapor and liquid phases to flow together between the evaporator and the condenser. It incorporates and evaporator where heat transfer is controlled by forced convection, an adiabatic transport section where transparent piping provides visualization of the flow regime, and a condenser where heat transfer is controlled by the shear between the gas and liquid phases. Stable operation of the system is observed during the variable accleration.

  1. Simulation model for a seven-phase BLDCM drive system

    NASA Astrophysics Data System (ADS)

    Park, Sang-Hoon; Lee, Won-Cheol; Lee, Jung-Hyo; Yu, Jae-Sung; Kim, Gyu-Sik; Won, Chung-Yuen

    2007-12-01

    BLDC motors have many advantages over brushed DC motors and induction motors. So, BLDC motors extend their application to many industrial fields. In this paper, the digital simulation and modeling of a 7-phase brushless DC motor have been presented. The 14-switch inverter and a 7-phase brushless DC motor drive system are simulated using hysteresis current controller and logic of switching pattern with the Boolean¡s function. Through some simulations, we found that our modeling and analysis of a 7-phase BLDCM with PWM inverter would be helpful for the further studies of the multi-phase BLDCM drive systems.

  2. Interconnecting Single-Phase Generation to the Utility Distribution System

    SciTech Connect

    Dugan, R.C.

    2001-12-05

    One potentially large source of underutilized distributed generation (DG) capacity exists in single-phase standby backup gensets on farms served from single-phase feeder laterals. Utilizing the excess capacity would require interconnecting to the utility system. Connecting single-phase gensets to the utility system presents some interesting technical issues that have not been previously investigated. This paper addresses several of the interconnection issues associated with this form of DG including voltage regulation, harmonics, overcurrent protection, and islanding. A significant amount of single-phase DG can be accommodated by the utility distribution system, but there are definite limitations due to the nature and location of the DG. These limitations may be more restrictive than is commonly assumed for three-phase DG installed on stronger parts of the electric distribution system.

  3. 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

  4. A synchronous phase detection system for an optical interferometric sensor

    NASA Astrophysics Data System (ADS)

    Bush, I. J.

    1982-05-01

    A system has been developed to accurately detect phase produced in optical interferometric sensors. The system employs optical heterodyning, and it synchronously detects optical phase by feeding an error signal back to a phase modulator in the reference leg of the interferometer. This system is seen to have properties similar to a phase-locked loop used for the demodulation of FM signals. The system model is second order and nonlinear, but a linear approximation serves to accurately describe the system in synchronous operation and is corroborated with well-matched empirical data. The complete model is simulated via computer techniques and is needed to describe the system's parameters that lead to loss and reacquisition of synchronization.

  5. Comparison of soil phosphorus status and organic matter composition in potato fields with different crop rotation systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cropping management practices influence soil phosphorus (P) availability and soil organic matter (SOM) quality. This chapter summarizes the impact of cropping systems and water management on soil phosphorus status and organic matter characteristics after the first full cycle of the 3-y crop rotation...

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Differential phase contrast X-ray imaging system and components

    DOEpatents

    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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Synchronous states of slowly rotating pendula

    NASA Astrophysics Data System (ADS)

    Kapitaniak, Marcin; Czolczynski, Krzysztof; Perlikowski, Przemysław; Stefanski, Andrzej; Kapitaniak, Tomasz

    2014-08-01

    Coupled systems that contain rotating elements are typical in physical, biological and engineering applications and for years have been the subject of intensive studies. One problem of scientific interest, which among others occurs in such systems is the phenomenon of synchronization of different rotating parts. Despite different initial conditions, after a sufficiently long transient, the rotating parts move in the same way - complete synchronization, or a permanent constant shift is established between their displacements, i.e., the angles of rotation - phase synchronization. Synchronization occurs due to dependence of the periods of rotating elements motion and the displacement of the base on which these elements are mounted. We review the studies on the synchronization of rotating pendula and compare them with the results obtained for oscillating pendula. As an example we consider the dynamics of the system consisting of n pendula mounted on the movable beam. The pendula are excited by the external torques which are inversely proportional to the angular velocities of the pendula. As the result of such excitation each pendulum rotates around its axis of rotation. It has been assumed that all pendula rotate in the same direction or in the opposite directions. We consider the case of slowly rotating pendula and estimate the influence of the gravity on their motion. We classify the synchronous states of the identical pendula and observe how the parameters mismatch can influence them. We give evidence that synchronous states are robust as they exist in the wide range of system parameters and can be observed in a simple experiment.

  17. 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

  18. 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

  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. 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