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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

    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 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

  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 Central

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-01-01

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

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

    PubMed

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-01-01

    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. 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.

  15. 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.

  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 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.

  7. 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.

  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

    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.

  1. 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

  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 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

  8. 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

  9. 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

  10. 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

  11. 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

  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

    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.

  16. 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.

  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. 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

  1. 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.

  2. 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.

  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. 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

  11. 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.

  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. 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

  14. 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.

  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. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  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 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

  10. 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

  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.

    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

  9. 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.

  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 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

  13. 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

  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. 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.

  19. 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

  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. 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

  10. 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.