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Sample records for axial flux permanent

  1. Advanced AC permanent magnet axial flux disc motor for electric passenger vehicle

    NASA Technical Reports Server (NTRS)

    Kliman, G. B.

    1982-01-01

    An ac permanent magnet axial flux disc motor was developed to operate with a thyristor load commutated inverter as part of an electric vehicle drive system. The motor was required to deliver 29.8 kW (40 hp) peak and 10.4 kW (14 hp) average with a maximum speed of 11,000 rpm. It was also required to run at leading power factor to commutate the inverter. Three motors were built.

  2. Axial flux, modular, permanent-magnet generator with a toroidal winding for wind turbine applications

    SciTech Connect

    Muljadi, E.; Butterfield, C.P.; Wan, Y.H.

    1998-07-01

    Permanent-magnet generators have been used for wind turbines for many years. Many small wind turbine manufacturers use direct-drive permanent-magnet generators. For wind turbine generators, the design philosophy must cover the following characteristics: low cost, light weight, low speed, high torque, and variable speed generation. The generator is easy to manufacture and the design can be scaled up for a larger size without major retooling. A modular permanent-magnet generator with axial flux direction was chosen. The permanent magnet used is NdFeB or ferrite magnet with flux guide to focus flux density in the air gap. Each unit module of the generator may consist of one, two, or more phases. Each generator can be expanded to two or more unit modules. Each unit module is built from simple modular poles. The stator winding is formed like a torus. Thus, the assembly process is simplified and the winding insertion in the slot is less tedious. The authors built a prototype of one unit module and performed preliminary tests in the laboratory. Follow up tests will be conducted in the lab to improve the design.

  3. An optimal design of coreless direct-drive axial flux permanent magnet generator for wind turbine

    NASA Astrophysics Data System (ADS)

    Ahmed, D.; Ahmad, A.

    2013-06-01

    Different types of generators are currently being used in wind power technology. The commonly used are induction generator (IG), doubly-fed induction generator (DFIG), electrically excited synchronous generator (EESG) and permanent magnet synchronous generator (PMSG). However, the use of PMSG is rapidly increasing because of advantages such as higher power density, better controllability and higher reliability. This paper presents an innovative design of a low-speed modular, direct-drive axial flux permanent magnet (AFPM) generator with coreless stator and rotor for a wind turbine power generation system that is developed using mathematical and analytical methods. This innovative design is implemented in MATLAB / Simulink environment using dynamic modelling techniques. The main focus of this research is to improve efficiency of the wind power generation system by investigating electromagnetic and structural features of AFPM generator during its operation in wind turbine. The design is validated by comparing its performance with standard models of existing wind power generators. The comparison results demonstrate that the proposed model for the wind power generator exhibits number of advantages such as improved efficiency with variable speed operation, higher energy yield, lighter weight and better wind power utilization.

  4. Investigation of mechanical field weakening of axial flux permanent magnet motor

    NASA Astrophysics Data System (ADS)

    Syaifuddin Mohd, M.; Aziz, A. Rashid A.; Syafiq Mohd, M.

    2015-12-01

    An investigation of axial flux permanent magnet motor (AFPM) characteristics was conducted with a proposed mechanical field weakening control mechanisms (by means of stator-rotor force manipulation) on the motor through modeling and experimentation. By varying the air gap between at least two bistable positions, the peak torque and top speed of the motor can be extended. The motor high efficiency region can also be extended to cover greater part of the motor operating points. An analytical model of the motor had been developed to study the correlation between the total attraction force (between the rotor and the stator) and the operating parameters of the motor. The test results shows that the motor output complies with the prediction of the research hypothesis and it is likely that a spring locking mechanism can be built to dynamically adjust the air gap of the motor to increase the operating range and could be applied in electric drivetrain applications to improve overall efficiency of electric and hybrid electric vehicles.

  5. Design, simulation and analysis of 3 kW low speed axial flux permanent magnet generator

    NASA Astrophysics Data System (ADS)

    Kasim, Muhammad; Irasari, Pudji; Hikmawan, Muhammad Fathul

    2016-03-01

    Design and simulation of an axial flux permanent magnet generator (AFPMG) have been described in this paper. It was designed using the single rotor - single stator construction. The analytical method was using in the design process. The design process also employed the simulation using Finite Element Method Magnetics (FEMM) 4.2 software for identifying the magnetic characteristic and heat transfer. The effect of fill factor (FF) variation on the generator performances also observed in this paper. The design result shows that using the selected FF, the conductor diameter, power output, efficiency and heat distribution are affected but not for the Bg. The generator output can achieve up to 5.2 kW using the FF 0.4 which is more than assumed power output at the pre-design using FF 0.3. It also can be seen that the increasing FF will increase the power output and the efficiency. Despite a higher temperature compared with FF 0.3 and 0.35, the value of 0.4 is the most appropriate FF for designing the AFPMG.

  6. Design and characterization of axial flux permanent magnet energy harvester for vehicle magnetorheological damper

    NASA Astrophysics Data System (ADS)

    Dong, Xiaomin

    2016-01-01

    An axial flux permanent magnet energy harvester (AFPMEH) is proposed and analyzed for a vehicle magneto-rheological (MR) damper. The relationship between the output voltage and the input excitations are analytically developed. Under different constant rotation speeds and sinusoidal excitations, the harvesting energy is numerically computed for different loads of pure resistance and coil in the MR damper. To check the performance of the proposed AFPMEH for the MR damper, the AFPMEH and MR damper are fabricated individually. Experiments are performed to measure the harvesting energy of the AFPMEH and the damping characteristics of the MR damper under different excited conditions. The excited conditions include three constant rotation speeds and sinusoidal inputs. Load inputs of the pure resistance and the coil of the MR damper are considered. The results show that the time history of the generated voltage of the AFPMEH in experiment is agreed well with that of the AFPMEH in simulation. Under constant rotation speeds, the root mean square (rms) of loaded voltage will increase with the increment of load, whereas the rms of power will be affected by the amplitude of load. The MR damper powered by the AFPMEH can almost obtain the similar damping characteristics of that external power supply. Under sinusoidal inputs, the rms of loaded voltage will increase with the increment of external loads, whereas the rms of power will be almost kept as a constant. The damping range of the MR damper can also be enlarged over 30% comparing to off-state damping force. A quarter car model with an MR damper powered by the AFPMEH is developed to investigate the control performance. The on-off skyhook control is adopted to tune the input current of the MR damper. The vibration performance of the MR suspension is investigated under different roads and vehicle speeds. The numerical results show that the MR suspension with the AFPMEH under on-off skyhook control can achieve better ride comfort

  7. Axial-flux modular permanent-magnet generator with a toroidal winding for wind-turbine applications

    SciTech Connect

    Muljadi, E.; Butterfield, C.P.; Wan, Y.H.

    1999-08-01

    Permanent-magnet (PM) generators have been used for wind turbines for many years. Many small wind-turbine manufacturers use direct-drive PM generators. For wind-turbine generators, the design philosophy must cover the following characteristics: low cost, light weight, low speed, high torque, and variable-speed generation. The generator is easy to manufacture and the design can be scaled up for a larger size without major retooling. A modular PM generator with axial flux direction was chosen. The permanent magnet used is NdFeB or ferrite magnet with flux guide to focus flux density in the air gap. Each unit module of the generator may consist of one, two, or more phases. Each generator can be expanded to two or more unit modules. Each unit module is built from simple modular poles. The stator winding is formed like a torus. Thus, the assembly process is simplified and the winding insertion in the slot is less tedious. The authors built a prototype of one unit module and performed preliminary tests in the laboratory. Follow-up tests will be conducted in the laboratory to improve the design.

  8. Axial bearings using superconductors and permanent magnets

    SciTech Connect

    Marion-Pera, M.C.; Yonnet, J.P.

    1995-05-01

    Contactless bearings are one of the applications of high temperature superconductors. Different structures of permanent magnets and superconductors are modeled assuming a total Meissner effect. Axial force of a few hundred Newtons and stiffness of around 100 N/mm can be achieved. Consequences of real superconducting material behavior are discussed.

  9. Permanent-magnet switched-flux machine

    DOEpatents

    Trzynadlowski, Andrzej M.; Qin, Ling

    2012-02-21

    A permanent-magnet switched-flux (PMSF) device has an outer rotor mounted to a shaft about a central axis extending axially through the PMSF device. First and second pluralities of permanent-magnets (PMs) are respectively mounted in first and second circles, radially outwardly in first and second transverse planes extending from first and second sections of the central axis adjacent to an inner surface of the outer rotor. An inner stator is coupled to the shaft and has i) a stator core having a core axis co-axial with the central axis; and ii) first and second pluralities of stator poles mounted in first and second circles, radially outwardly from the stator core axis in the first and second transverse planes. The first and second pluralities of PMs each include PMs of alternating polarity.

  10. Permanent-magnet switched-flux machine

    DOEpatents

    Trzynadlowski, Andrzej M.; Qin, Ling

    2010-01-12

    A permanent-magnet switched-flux (PMSF) device has a ferromagnetic outer stator mounted to a shaft about a central axis extending axially through the PMSF device. Pluralities of top and bottom stator poles are respectively mounted in first and second circles, radially outwardly in first and second transverse planes extending from first and second sections of the central axis adjacent to an inner surface of the ferromagnetic outer stator. A ferromagnetic inner rotor is coupled to the shaft and has i) a rotor core having a core axis co-axial with the central axis; and ii) first and second discs having respective outer edges with first and second pluralities of permanent magnets (PMs) mounted in first and second circles, radially outwardly from the rotor core axis in the first and second transverse planes. The first and second pluralities of PMs each include PMs of alternating polarity.

  11. Permanent-magnet switched-flux machine

    DOEpatents

    Trzynadlowski, Andrzej M.; Qin, Ling

    2011-06-14

    A permanent-magnet switched-flux (PMSF) device has an outer rotor mounted to a shaft about a central axis extending axially through the PMSF device. First and second pluralities of permanent-magnets (PMs) are respectively mounted in first and second circles, radially outwardly in first and second transverse planes extending from first and second sections of the central axis adjacent to an inner surface of the outer rotor. An inner stator is coupled to the shaft and has i) a stator core having a core axis co-axial with the central axis; and ii) first and second pluralities of stator poles mounted in first and second circles, radially outwardly from the stator core axis in the first and second transverse planes. The first and second pluralities of PMs each include PMs of alternating polarity.

  12. Axial flux machine, stator and fabrication method

    DOEpatents

    Carl, Ralph James

    2004-03-16

    An axial flux machine comprises: a soft magnetic composite stator extension positioned in parallel with a rotor disk and having slots; soft magnetic composite pole pieces attached to the stator extension and facing a permanent magnet on the rotor disk, each comprising a protrusion situated within a respective one of the slots, each protrusion shaped so as to facilitate orientation of the respective pole piece with respect to the stator extension; electrical coils, each wrapped around a respective one of the pole pieces. In another embodiment the soft magnetic composite pole pieces each comprise a base portion around with the electrical coils are wound and a trapezoidal shield portion a plurality of heights with a first height in a first region being longer than a second height in a second region, the second region being closer to a pole-to-pole gap than the first region.

  13. Permanent magnet flux-biased magnetic actuator with flux feedback

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J. (Inventor)

    1991-01-01

    The invention is a permanent magnet flux-biased magnetic actuator with flux feedback for adjustably suspending an element on a single axis. The magnetic actuator includes a pair of opposing electromagnets and provides bi-directional forces along the single axis to the suspended element. Permanent magnets in flux feedback loops from the opposing electromagnets establish a reference permanent magnet flux-bias to linearize the force characteristics of the electromagnets to extend the linear range of the actuator without the need for continuous bias currents in the electromagnets.

  14. Electromagnetic design analysis and performance improvement of axial field permanent magnet generator for small wind turbine

    NASA Astrophysics Data System (ADS)

    Jung, Tae-Uk

    2012-04-01

    Axial field permanent magnet (AFPM) generators are widely applied for the small wind turbine. The output power of conventional AFPM generator, AFER-NS (Axial Field External Rotor-Non Slotted) generator, is limited by the large reluctance by the long air-gap flux paths. In this paper, the novel structure of AFPM generator, AFIR-S (Axial Field Inner Rotor-Slotted) generator, is suggested to improve the output characteristics. The electromagnetic design analysis and the design improvement of the suggested AFIR-S generator are studied. Firstly, the electromagnetic design analysis was done to increase the power density. Secondly, the design optimizations of the rotor pole-arc ratio and skew angle to increase the output power and to reduce the cogging torque. Finally, the output performances of AFER-NS and AFIR-S generator are compared with each other.

  15. Design of a Modular E-Core Flux Concentrating Axial Flux Machine

    SciTech Connect

    Husain, Tausif; Sozer, Yilmaz; Husain, Iqbal; Muljadi, Eduard

    2015-09-02

    In this paper a novel E-Core axial flux machine is proposed. The machine has a double stator-single rotor configuration with flux concentrating ferrite magnets, and pole windings across each leg of an E-Core stator. E-Core stators with the proposed flux-concentrating rotor arrangement result in better magnet utilization and higher torque density. The machine also has a modular structure facilitating simpler construction. This paper presents a single phase and a three-phase version of the E-Core machine. Case study for a 1.1 kW, 400 rpm machine for both the single phase and three-phase axial flux machine is presented. The results are verified through 3D finite element analysis.

  16. Design of a Modular E-Core Flux Concentrating Axial Flux Machine: Preprint

    SciTech Connect

    Husain, Tausif; Sozer, Yilmaz; Husain, Iqbal; Muljadi, Eduard

    2015-08-24

    In this paper a novel E-Core axial flux machine is proposed. The machine has a double-stator, single-rotor configuration with flux-concentrating ferrite magnets and pole windings across each leg of an E-Core stator. E-Core stators with the proposed flux-concentrating rotor arrangement result in better magnet utilization and higher torque density. The machine also has a modular structure facilitating simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis. facilitating simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis.

  17. Localization for robotic capsule looped by axially magnetized permanent-magnet ring based on hybrid strategy

    PubMed Central

    Yang, Wanan; Li, Yan; Qin, Fengqing

    2015-01-01

    To actively maneuver a robotic capsule for interactive diagnosis in the gastrointestinal tract, visualizing accurate position and orientation of the capsule when it moves in the gastrointestinal tract is essential. A possible method that encloses the circuits, batteries, imaging device, etc into the capsule looped by an axially magnetized permanent-magnet ring is proposed. Based on expression of the axially magnetized permanent-magnet ring’s magnetic fields, a localization and orientation model was established. An improved hybrid strategy that combines the advantages of particle-swarm optimization, clone algorithm, and the Levenberg–Marquardt algorithm was found to solve the model. Experiments showed that the hybrid strategy has good accuracy, convergence, and real time performance. PMID:25733935

  18. Radiofrequency hydrogen ion source with permanent magnets providing axial magnetic field

    SciTech Connect

    Oikawa, Kohei Saito, Yuta; Komizunai, Shota; Takahashi, Kazunori; Ando, Akira

    2014-02-15

    Uniform axial magnetic field of about 70 G is applied to a radiofrequency (rf) hydrogen ion source by arrays of permanent magnets. The plasma density and electron temperature downstream of the source and near the magnetic filter are compared with those in the previously described ion source, where the axial field has been applied by two solenoids. The source is operated at ∼350 kHz and above 10 kW rf power with a field-effect-transistor-based invertor power supply in 1.5 Pa hydrogen. The results show that the plasma density of ∼10{sup 19} m{sup −3} near the source exit and ∼10{sup 18} m{sup −3} near the magnetic filter can be obtained, which are higher than those with the solenoids.

  19. Radiofrequency hydrogen ion source with permanent magnets providing axial magnetic field

    NASA Astrophysics Data System (ADS)

    Oikawa, Kohei; Saito, Yuta; Komizunai, Shota; Takahashi, Kazunori; Ando, Akira

    2014-02-01

    Uniform axial magnetic field of about 70 G is applied to a radiofrequency (rf) hydrogen ion source by arrays of permanent magnets. The plasma density and electron temperature downstream of the source and near the magnetic filter are compared with those in the previously described ion source, where the axial field has been applied by two solenoids. The source is operated at ˜350 kHz and above 10 kW rf power with a field-effect-transistor-based invertor power supply in 1.5 Pa hydrogen. The results show that the plasma density of ˜1019 m-3 near the source exit and ˜1018 m-3 near the magnetic filter can be obtained, which are higher than those with the solenoids.

  20. Radiofrequency hydrogen ion source with permanent magnets providing axial magnetic field.

    PubMed

    Oikawa, Kohei; Saito, Yuta; Komizunai, Shota; Takahashi, Kazunori; Ando, Akira

    2014-02-01

    Uniform axial magnetic field of about 70 G is applied to a radiofrequency (rf) hydrogen ion source by arrays of permanent magnets. The plasma density and electron temperature downstream of the source and near the magnetic filter are compared with those in the previously described ion source, where the axial field has been applied by two solenoids. The source is operated at ∼350 kHz and above 10 kW rf power with a field-effect-transistor-based invertor power supply in 1.5 Pa hydrogen. The results show that the plasma density of ∼10(19) m(-3) near the source exit and ∼10(18) m(-3) near the magnetic filter can be obtained, which are higher than those with the solenoids.

  1. Effect of axial magnetic field on a 2.45 GHz permanent magnet ECR ion source.

    PubMed

    Nakamura, T; Wada, H; Asaji, T; Furuse, M

    2016-02-01

    Herein, we conduct a fundamental study to improve the generation efficiency of a multi-charged ion source using argon. A magnetic field of our electron cyclotron resonance ion source is composed of a permanent magnet and a solenoid coil. Thereby, the axial magnetic field in the chamber can be tuned. Using the solenoid coil, we varied the magnetic field strength in the plasma chamber and measured the ion beam current extracted at the electrode. We observed an approximately three times increase in the Ar(4+) ion beam current when the magnetic field on the extractor-electrode side of the chamber was weakened. From our results, we can confirm that the multi-charged ion beam current changes depending on magnetic field intensity in the plasma chamber. PMID:26931955

  2. Permanent Magnet Spiral Motor for Magnetic Gradient Energy Utilization: Axial Magnetic Field

    NASA Astrophysics Data System (ADS)

    Valone, Thomas F.

    2010-01-01

    The Spiral Magnetic Motor, which can accelerate a magnetized rotor through 90% of its cycle with only permanent magnets, was an energy milestone for the 20th century patents by Kure Tekkosho in the 1970's. However, the Japanese company used old ferrite magnets which are relatively weak and an electrically-powered coil to jump start every cycle, which defeated the primary benefit of the permanent magnet motor design. The principle of applying an inhomogeneous, anisotropic magnetic field gradient force Fz = μ cos φ dB/dz, with permanent magnets is well-known in physics, e.g., Stern-Gerlach experiment, which exploits the interaction of a magnetic moment with the aligned electron spins of magnetic domains. In this case, it is applied to dB/dθ in polar coordinates, where the force Fθ depends equally on the magnetic moment, the cosine of the angle between the magnetic moment and the field gradient. The radial magnetic field increases in strength (in the attractive mode) or decreases in strength (in the repulsive mode) as the rotor turns through one complete cycle. An electromagnetic pulsed switching has been historically used to help the rotor traverse the gap (detent) between the end of the magnetic stator arc and the beginning (Kure Tekko, 1980). However, alternative magnetic pulse and switching designs have been developed, as well as strategic eddy current creation. This work focuses on the switching mechanism, novel magnetic pulse methods and advantageous angular momentum improvements. For example, a collaborative effort has begun with Toshiyuki Ueno (University of Tokyo) who has invented an extremely low power, combination magnetostrictive-piezoelectric (MS-PZT) device for generating low frequency magnetic fields and consumes "zero power" for static magnetic field production (Ueno, 2004 and 2007a). Utilizing a pickup coil such as an ultra-miniature millihenry inductor with a piezoelectric actuator or simply Wiegand wire geometry, it is shown that the necessary

  3. Effects of slot closure by soft magnetic powder wedge material in axial-field permanent magnet brushless machines

    NASA Astrophysics Data System (ADS)

    Gair, S.; Eastham, J. F.; Canova, A.

    1996-04-01

    The article reports on a study of the effects of slot closure in axial-field permanent magnet brushless machines by a two-dimensional finite element method (2D FEM) of analysis. The closure of the slots is made by using soft magnetic powder wedge material. Parameter values and machine performance for the open and closed slot configuration are computed. In order to test the 2D FEM model, calculated results are compared with measurements and favorable agreement is shown.

  4. Direct control of air gap flux in permanent magnet machines

    DOEpatents

    Hsu, John S.

    2000-01-01

    A method and apparatus for field weakening in PM machines uses field weakening coils (35, 44, 45, 71, 72) to produce flux in one or more stators (34, 49, 63, 64), including a flux which counters flux normally produced in air gaps between the stator(s) (34, 49, 63, 64) and the rotor (20, 21, 41, 61) which carries the PM poles. Several modes of operation are introduced depending on the magnitude and polarity of current in the field weakening coils (35, 44, 45, 71, 72). The invention is particularly useful for, but not limited to, the electric vehicle drives and PM generators.

  5. Equilibrium and Steady State of Dense Z-Pinches Superposing a Small Amount of Axial Flux

    NASA Astrophysics Data System (ADS)

    Hashimoto, Mitsuhiro; Miyamoto, Tetsu

    2016-07-01

    The pressure equilibrium and steady state of z-pinches trapping a small amount of axial magnetic flux are studied. The Bennett relation and the Pease-Braginskii-current are modified, taking into account the superposed axial field. The line energy density decreases in the modified Bennett relation, but the decrease is only of the order ɛ2, where ɛ = (the axial field strength at the axis)/(the azimuthal field strength at the plasma periphery) ≪ 1. On the other hand, the current in the steady state can increase without being limited by the Pease-Braginskii-current. Hence, the radiation collapse is prevented. The decrease of line energy density in the modified Bennett relation is almost canceled in the steady state.

  6. Design and market considerations for axial flux superconducting electric machine design

    NASA Astrophysics Data System (ADS)

    Ainslie, M. D.; George, A.; Shaw, R.; Dawson, L.; Winfield, A.; Steketee, M.; Stockley, S.

    2014-05-01

    In this paper, the authors investigate a number of design and market considerations for an axial flux superconducting electric machine design that uses high temperature superconductors. The axial flux machine design is assumed to utilise high temperature superconductors in both wire (stator winding) and bulk (rotor field) forms, to operate over a temperature range of 65-77 K, and to have a power output in the range from 10s of kW up to 1 MW (typical for axial flux machines), with approximately 2-3 T as the peak trapped field in the bulk superconductors. The authors firstly investigate the applicability of this type of machine as a generator in small- and medium-sized wind turbines, including the current and forecasted market and pricing for conventional turbines. Next, a study is also carried out on the machine's applicability as an in-wheel hub motor for electric vehicles. Some recommendations for future applications are made based on the outcome of these two studies. Finally, the cost of YBCO-based superconducting (2G HTS) wire is analysed with respect to competing wire technologies and compared with current conventional material costs and current wire costs for both 1G and 2G HTS are still too great to be economically feasible for such superconducting devices.

  7. Torsional Alfvén waves in solar magnetic flux tubes of axial symmetry

    NASA Astrophysics Data System (ADS)

    Murawski, K.; Solov'ev, A.; Musielak, Z. E.; Srivastava, A. K.; Kraśkiewicz, J.

    2015-05-01

    Aims: Propagation and energy transfer of torsional Alfvén waves in solar magnetic flux tubes of axial symmetry is studied. Methods: An analytical model of a solar magnetic flux tube of axial symmetry is developed by specifying a magnetic flux and deriving general analytical formulas for the equilibrium mass density and gas pressure. The main advantage of this model is that it can be easily adopted to any axisymmetric magnetic structure. The model is used to numerically simulate the propagation of nonlinear Alfvén waves in such 2D flux tubes of axial symmetry embedded in the solar atmosphere. The waves are excited by a localized pulse in the azimuthal component of velocity and launched at the top of the solar photosphere, and they propagate through the solar chromosphere, the transition region, and into the solar corona. Results: The results of our numerical simulations reveal a complex scenario of twisted magnetic field lines and flows associated with torsional Alfvén waves, as well as energy transfer to the magnetoacoustic waves that are triggered by the Alfvén waves and are akin to the vertical jet flows. Alfvén waves experience about 5% amplitude reflection at the transition region. Magnetic (velocity) field perturbations that experience attenuation (growth) with height agree with analytical findings. The kinetic energy of magnetoacoustic waves consists of 25% of the total energy of Alfvén waves. The energy transfer may lead to localized mass transport in the form of vertical jets, as well as to localized heating because slow magnetoacoustic waves are prone to dissipation in the inner corona.

  8. Dual-rotor, radial-flux, toroidally-wound, permanent-magnet machine

    DOEpatents

    Qu, Ronghai; Lipo, Thomas A.

    2005-08-02

    The present invention provides a novel dual-rotor, radial-flux, toroidally-wound, permanent-magnet machine. The present invention improves electrical machine torque density and efficiency. At least one concentric surface-mounted permanent magnet dual-rotor is located inside and outside of a torus-shaped stator with back-to-back windings, respectively. The machine substantially improves machine efficiency by reducing the end windings and boosts the torque density by at least doubling the air gap and optimizing the machine aspect ratio.

  9. The effect of axial conduction on a thermosyphon with prescribed heat flux

    NASA Astrophysics Data System (ADS)

    Sen, M.; Ramos, E.; Trevino, C.; Salazar, O.

    A one-dimensional model of a natural convection loop of arbitrary shape with prescribed heat flux over its entire length is analyzed. The effect of inclusion of axial conduction is considered in detail. Steady state solutions are presented for the velocity and temperature fields. The transcendental equation for the fluid velocity is studied for the special case of a toroidal geometry with sinusoidal heating. The time-dependent toroidal problem is reduced to a set of three ordinary differential equations which have steady, periodic and chaotic solutions. The stability characteristics of the equilibrium solutions are discussed. The nonconducting model is found to exhibit supercritical instability while the conducting model is subcritical.

  10. Ultra-high speed permanent magnet axial gap alternator with multiple stators

    DOEpatents

    Hawsey, Robert A.; Bailey, J. Milton

    1991-01-01

    An ultra-high speed, axial gap alternator that can provide an output to a plurality of loads, the alternator providing magnetic isolation such that operating conditions in one load will not affect operating conditions of another load. This improved alternator uses a rotor member disposed between a pair of stator members, with magnets disposed in each of the rotor member surfaces facing the stator members. The magnets in one surface of the rotor member, which alternate in polarity, are isolated from the magnets in the other surface of the rotor member by a disk of magnetic material disposed between the two sets of magents. In the preferred embodiment, this disk of magnetic material is laminated between two layers of non-magnetic material that support the magnets, and the magnetic material has a peripheral rim that extends to both surfaces of the rotor member to enhance the structural integrity. The stator members are substantially conventional in construction in that equally-spaced and radially-oriented slots are provided, and winding members are laid in these slots. A unit with multiple rotor members and stator members is also described.

  11. Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source

    SciTech Connect

    Kumar, Narender; Rodrigues, G. Lakshmy, P. S.; Mathur, Y.; Ahuja, R.; Kanjilal, D.; Baskaran, R.

    2014-02-15

    A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the “off-resonance” mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied.

  12. Critical heat flux experiments in an internally heated annulus with a non-uniform, alternate high and low axial heat flux distribution (AWBA Development Program)

    SciTech Connect

    Beus, S.G.; Seebold, O.P.

    1981-02-01

    Critical heat flux experiments were performed with an alternate high and low heat flux profile in an internally heated annulus. The heated length was 84 inches (213 cm) with a chopped wave heat flux profile over the last 24 inches (61 cm) having a maximum-to-average heat flux ratio of 1.26. Three test sections were employed: one with an axially uniform heat flux profile as a base case and two with 60 inch (152 cm) uniform and 24 inch (61 cm) alternating high and low heat flux sections. The third test section had a 2.15 inch (5.46 cm) section with a peak-to-average heat flux ratio of 2.19 (hot patch) superimposed at the exit end of the alternating high and low heat flux profile.

  13. Two regimes of flux scaling in axially homogeneous turbulent convection in vertical tube

    NASA Astrophysics Data System (ADS)

    Pawar, Shashikant S.; Arakeri, Jaywant H.

    2016-08-01

    From experiments of axially homogeneous turbulent convection in a vertical tube using heat (Prandtl number Pr≃6 ) and brine (Pr≃600 ) we show that at sufficiently high Rayleigh numbers (Rag), the Nusselt number Nug˜(RagPr)1/2, which corresponds to the so-called ultimate regime scaling. In heat experiments below certain Rag,however,there is transition to a new regime, Nug˜(RagPr)0.3. This transition also seems to exist in earlier reported data for Pr=1 and Pr≃600 , at different Rag. However, the transition occurs at a single Grashof number, Grgc≃1.6 ×105 , and unified flux scalings for Pr≥1 , Nug/Pr˜Grg0.3, and Nug/Pr˜Grg1/2 can be given for the two regimes.

  14. Design of an axial flux PM motor using magnetic and thermal equivalent network

    NASA Astrophysics Data System (ADS)

    Mignot, Romain-Bernard; Glises, Raynal; Espanet, Christophe; Saint Ellier, Emeline; Dubas, Frédéric; Chamagne, Didier

    2013-09-01

    This paper deals with the development of a new generation of electric motors (7.5-15 kW) for automotive powertrains. The target is a full electric direct drive vehicle, for the particular application to heavy quadricycles. An original axial flux PM structure is proposed due to the simplicity of its manufacturing. However it leads to a 3D structure, difficult to study. The paper deals with analytical models that can be used to achieve the analysis and the sizing of the motor. The electromagnetic behavior is modeled using a simple magnetic equivalent network and the thermal behavior is analyzed with a thermal network. Finally, the analytical results are compared to those experimentally obtained and it proves the interest of the proposed structure: the construction is simple and the performances are satisfying.

  15. Suspension force control of bearingless permanent magnet slice motor based on flux linkage identification.

    PubMed

    Zhu, Suming; Zhu, Huangqiu

    2015-07-01

    The control accuracy and dynamic performance of suspension force are confined in the traditional bearingless permanent magnet slice motor (BPMSM) control strategies because the suspension force control is indirectly achieved by adopting a closed loop of displacement only. Besides, the phase information in suspension force control relies on accurate measurement of rotor position, making the control system more complex. In this paper, a new suspension force control strategy with displacement and radial suspension force double closed loops is proposed, the flux linkage of motor windings is identified based on voltage-current model and the flexibility of motor control can be improved greatly. Simulation and experimental results show that the proposed suspension force control strategy is effective to realize the stable operation of the BPMSM.

  16. Optimal design of a novel hybrid MR brake for motorcycles considering axial and radial magnetic flux

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. H.; Choi, S. B.

    2012-05-01

    This work presents an optimal solution of a new type of motorcycle brake featuring different smart magnetorheological (MR) fluids. In this study, typical types of commercial MR fluid are considered there for the design of a motorcycle MR brake; MRF-122-2ED (low yield stress), MRF-132-DG (medium yield stress) and MRF-140-CG (high yield stress). As a first step, a new configuration featuring a T-shaped drum MR brake is introduced and a hybrid concept of magnetic circuit (using both axial and radial magnetic flux) to generate braking force is analyzed based on the finite element method. An optimal design of the MR brake considering the required braking torque, the temperature due to friction of the MR fluid, the mass of the brake system and all significant geometric dimensions is then performed. For the optimization, the finite element analysis (FEA) is used to achieve principal geometric dimensions of the MR brake. In addition, the size, mass and power consumption of three different MR motorcycle brakes are quantitatively analyzed and compared.

  17. A dual-channel flux-switching permanent magnet motor for hybrid electric vehicles

    NASA Astrophysics Data System (ADS)

    Hua, Wei; Wu, Zhongze; Cheng, Ming; Wang, Baoan; Zhang, Jianzhong; Zhou, Shigui

    2012-04-01

    The flux-switching permanent magnet (FSPM) motor is a relatively novel brushless machine having both magnets and concentrated windings in the stator, which exhibits inherently sinusoidal PM flux-linkage, back-EMF waveforms, and high torque capability. However, in the application of hybrid electric vehicles, it is essential to prevent magnets and armature windings moving in radial direction due to the possible vibration during operation, and to ensure fault-tolerant capability. Hence, in this paper based on an original FSPM motor, a dual-channel FSPM (DC-FSPM) motor with modified structure to fix both armature windings and magnets and improved reliability is proposed for a practical 10 kW integral starter/generator (ISG) in hybrid electric vehicles. The influences of different solutions and the end-effect on the static characteristics, are evaluated based on the 2D and 3D finite element analysis, respectively. Finally, both the predicted and experimental results, compared with a prototype DC-FSPM motor and an interior PM motor used in Honda Civic, confirm that the more sinusoidal back-EMF waveform and lower torque ripple can be achieved in the DC-FSPM motor, whereas the torque is smaller under the same coil current.

  18. A novel single-phase flux-switching permanent magnet linear generator used for free-piston Stirling engine

    NASA Astrophysics Data System (ADS)

    Zheng, Ping; Sui, Yi; Tong, Chengde; Bai, Jingang; Yu, Bin; Lin, Fei

    2014-05-01

    This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PM linear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density.

  19. Design considerations in the employment of rare earth-cobalt permanent magnets as flux sources

    NASA Astrophysics Data System (ADS)

    Leupold, H. A.

    1982-11-01

    The design advantages resulting from the linear demagnetization curves of rare-earth permanent magnets are discussed. The magnetic analogue to Ohm's law is derived and its affiliation illustrated by an example. Other aspects of design, such as the replacement of magnetic circuits with equivalent pole densities and the significance of the energy product, are also discussed.

  20. Torque ripple minimization of flux-controllable stator-permanent-magnet brushless motors using harmonic current injection

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoyong; Cheng, Ming; Chau, K. T.; Yu, Chuang

    2009-04-01

    Due to the nature of salient poles in both the stator and rotor, the new class of flux-controllable stator-permanent-magnet brushless (FC-SPMBL) motors still suffers from severe torque ripples. In this paper, a new torque ripple minimization approach, namely, the harmonic current injection method, is proposed and implemented in the FC-SPMBL motor. By injecting proper harmonic current components into the fundamental current, the variation of instantaneous power is kept to minimum. Thus, the torque ripple is minimized. Both simulation and experimental results show that the proposed approach can effectively suppress the torque ripple.

  1. Characteristic and magnetic field analysis of a high temperature superconductor axial-flux coreless induction maglev motor.

    PubMed

    Wei, Qin; Yu, Fan; Jin, Fang; Shuo, Li; Guoguo, Li; Gang, Lv

    2012-04-01

    A new high temperature superconductor axial-flux coreless maglev motor (HTS AFIM) is proposed, of which the primary windings are made of HTS tapes and the secondary is a non-magnetic conductor. The main works of this paper are the magnetic-field computation and characteristics analysis of HTS AFIM. For the first one, the reduction of magnetic fields near outer and inner radius of the HTS AFIM is solved by introducing the sub-loop electro-magnetic model along the radial position. For the second one, the AC losses of HTS coils are calculated. The relationships between the device's characteristics and device parameters are presented, and the results indicate that under certain frequency and current levitation device can output enough lift force. The conclusions are verified by finite element calculations. PMID:22393268

  2. Axial symmetry breaking in self-induced flavor conversionof supernova neutrino fluxes.

    PubMed

    Raffelt, Georg; Sarikas, Srdjan; de Sousa Seixas, David

    2013-08-30

    Neutrino-neutrino refraction causes self-induced flavor conversion in dense neutrino fluxes. For the first time, we include the azimuth angle of neutrino propagation as an explicit variable and find a new generic multi-azimuth-angle instability which, for simple spectra, occurs in the normal neutrino mass hierarchy. Matter suppression of this instability in supernovae requires larger densities than the traditional bimodal case. The new instability shows explicitly that solutions of the equations for collective flavor oscillations need not inherit the symmetries of initial or boundary conditions. This change of paradigm requires reconsideration of numerous results in this field.

  3. A comparison of methane flux rates from the margins of a permanent wetland and an ephemeral wetland in southern Minnesota

    NASA Astrophysics Data System (ADS)

    Nelson, L. C.; Kannenberg, S.; Ludwig, S.; Rich, H.; Spawn, S.; Porterfield, J.; Schade, J. D.

    2012-12-01

    The degree of expansion and contraction of wetlands is likely to change as climate change alters drought and precipitation events. As wetland size becomes more dynamic, the extent and duration of inundation of soils on their margins will change. The amount of methane released from wetlands will also change since methanogens thrive in anoxic, saturated soils. It is critical to study the factors that influence methane emissions from wetlands because methane is 20 times more effective at trapping heat in the atmosphere than carbon dioxide. The objective of our research was to compare methane flux rates from the margins of a permanent wetland and an ephemeral wetland. We also assessed the impact of Reed Canary Grass (Phalaris arundinacea) on transport of methane from the soil to the atmosphere. Methane flux emissions were measured using portable gas flux chambers at Bakko Pond (a permanent wetland) and East Coyote Pond (an ephemeral wetland) on the St. Olaf College Natural Lands in southern Minnesota. At each wetland, we measured methane emissions from plots of clipped and unclipped Reed Canary Grass. We found no statistical difference between clipped and unclipped plots, suggesting that a diffusive gas transport system rather than a coupling of a diffusive and convective gas transport emits methane. We also found that the average rate of methane flux was higher at East Coyote Pond at both the wet Reed Canary Grass and dry Reed Canary Grass sites, when compared to the dry Reed Canary Grass site at Bakko Pond. Higher methane emission rates at East Coyote Pond is consistent with the characteristics of a wetland with a shallow bank where marginal soil is frequently inundated with water, creating a favorable anoxic environment for active methanogens. In contrast, Bakko Pond has a steep embankment, reducing soil saturation. We also found that soil moisture was strongly correlated with methane flux rates between the sites and over time within a site. Overall, our results

  4. Flux Leakage Measurements for Defect Characterization Using a High Precision 3-AXIAL Gmr Magnetic Sensor

    NASA Astrophysics Data System (ADS)

    Pelkner, M.; Blome, M.; Reimund, V.; Thomas, H.-M.; Kreutzbruck, M.

    2011-06-01

    High-precision magnetic field sensors are of increasing interest in non destructive testing (NDT). In particular GMR-sensors (giant magneto resistance) are qualified because of their high sensitivity, high signal-to-noise ratio and high spatial resolution. With a GMR-gradiometer and a 3D-GMR-magnetometer we performed magnetic flux leakage measurements of artificial cracks and cracks of a depth of ≤50 μm still could be dissolved with a sufficient high signal-to-noise ratio. A semi-analytic magnetic dipole model that allows realistic GMR sensor characteristics to be incorporated is used for swiftly predicting magnetic stray fields. The reliable reconstruction based on measurements of artificial rectangular-shaped defects is demonstrated.

  5. Modeling and output tracking of transverse flux permanent magnet machines using high gain observer and RBF neural network.

    PubMed

    Karimi, H R; Babazadeh, A

    2005-10-01

    This paper deals with modeling and adaptive output tracking of a transverse flux permanent magnet machine as a nonlinear system with unknown nonlinearities by utilizing high gain observer and radial basis function networks. The proposed model is developed based on computing the permeance between rotor and stator using quasiflux tubes. Based on this model, the techniques of feedback linearization and Hinfinity control are used to design an adaptive control law for compensating the unknown nonlinear parts, such as the effect of cogging torque, as a disturbance is decreased onto the rotor angle and angular velocity tracking performances. Finally, the capability of the proposed method in tracking both the angle and the angular velocity is shown in the simulation results.

  6. Investigation of a new flux-modulated permanent magnet brushless motor for EVs.

    PubMed

    Fan, Ying; Gu, Lingling; Luo, Yong; Han, Xuedong; Cheng, Ming

    2014-01-01

    This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation. PMID:24883405

  7. Investigation of a New Flux-Modulated Permanent Magnet Brushless Motor for EVs

    PubMed Central

    Gu, Lingling; Luo, Yong; Han, Xuedong

    2014-01-01

    This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation. PMID:24883405

  8. Investigation of a new flux-modulated permanent magnet brushless motor for EVs.

    PubMed

    Fan, Ying; Gu, Lingling; Luo, Yong; Han, Xuedong; Cheng, Ming

    2014-01-01

    This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation.

  9. Phase II CRADA ORNL99-0568 Report : Developing Transmission-Less Inverter Drive Systems for Axial-Gap Permanent magnet Accessory and Traction Motors and Generators

    SciTech Connect

    McKeever, J.W.

    2001-08-06

    Researchers of the Oak Ridge National Laboratory's (ORNLs) Power Electronics and Electric Machine Research Center (PEEMRC) collaborated with Visual Computing Systems (VCS) to develop an electric axial-gap permanent magnet (PM) motor controlled by a self-sensing inverter for driving vehicle accessories such as power steering, air conditioning, and brakes. VCS designed an 8 kW motor based on their Segmented Electromagnetic Array (SEMA) technology. ORNL designed a 10 kW inverter to fit within the volume of a housing, which had been integrated with the motor. This modular design was pursued so that multiple modules could be used for higher power applications. ORNL built the first inverter under the cooperative research and development agreement (CRADA) ORNL 98-0514 and drove a refurbished Delta motor with no load during the Merit Review at ORNL on Monday, May 17, 1999. Inverter circuitry and instructions for assembling the inverters were sent to VCS. A report was prepared and delivered during the Future Car Congress in April 2000, at Arlington, Virginia. Collaboration continued under CRADA ORNL 99-0568 as VCS designed and built a SEMA motor with a dual coil platter to be the traction motor for an electric truck. VCS and ORNL assembled two 45 kW inverters. Each inverter drove one coil, which was designed to deliver 15 kW continuous power and 45 kW peak power for 90 s. The vehicle was road tested as part of the Future Truck Competition. A report was prepared and delivered during the PCIM in October 2000, at Boston, Massachusetts.

  10. Design and application of permanent magnet flux sources for mechanical testing of magnetoactive elastomers at variable field directions

    NASA Astrophysics Data System (ADS)

    Hiptmair, F.; Major, Z.; Haßlacher, R.; Hild, S.

    2015-08-01

    Magnetoactive elastomers (MAEs) are a class of smart materials whose mechanical properties can be rapidly and reversibly changed by an external magnetic field. Due to this tunability, they are useable for actuators or in active vibration control applications. An extensive magnetomechanical characterization is necessary for MAE material development and requires experiments under cyclic loading in uniform but variable magnetic fields. MAE testing apparatus typically rely on fields of adjustable strength, but fixed (transverse) direction, often provided by electromagnets. In this work, two permanent magnet flux sources were developed as an add-on for a modular test stand, to allow for mechanical testing in uniform fields of variable direction. MAE specimens, based on a silicone matrix with isotropic and anisotropic carbonyl iron particle distributions, were subjected to dynamic mechanical analysis under different field and loading configurations. The magneto-induced increase of stiffness and energy dissipation was determined by the change of the hysteresis loop area and dynamic modulus values. A distinct influence of the composite microstructure and the loading state was observed. Due to the very soft and flexible matrix used for preparing the MAE samples, the material stiffness and damping behavior could be varied over a wide range via the applied field direction and intensity.

  11. Design and application of permanent magnet flux sources for mechanical testing of magnetoactive elastomers at variable field directions.

    PubMed

    Hiptmair, F; Major, Z; Haßlacher, R; Hild, S

    2015-08-01

    Magnetoactive elastomers (MAEs) are a class of smart materials whose mechanical properties can be rapidly and reversibly changed by an external magnetic field. Due to this tunability, they are useable for actuators or in active vibration control applications. An extensive magnetomechanical characterization is necessary for MAE material development and requires experiments under cyclic loading in uniform but variable magnetic fields. MAE testing apparatus typically rely on fields of adjustable strength, but fixed (transverse) direction, often provided by electromagnets. In this work, two permanent magnet flux sources were developed as an add-on for a modular test stand, to allow for mechanical testing in uniform fields of variable direction. MAE specimens, based on a silicone matrix with isotropic and anisotropic carbonyl iron particle distributions, were subjected to dynamic mechanical analysis under different field and loading configurations. The magneto-induced increase of stiffness and energy dissipation was determined by the change of the hysteresis loop area and dynamic modulus values. A distinct influence of the composite microstructure and the loading state was observed. Due to the very soft and flexible matrix used for preparing the MAE samples, the material stiffness and damping behavior could be varied over a wide range via the applied field direction and intensity. PMID:26329233

  12. Improvement of the propulsion force for HTSC-permanent magnet hybrid magnetically levitated carrying system by using the pinned flux of HTSC

    NASA Astrophysics Data System (ADS)

    Ikeda, M.; Sasaki, R.; Ueno, T.; Ohashi, S.

    Magnetically levitated carrying system has been developed. In this system, pinning force of high temperature bulk superconductor (HTSC) is used for the levitation and guidance. The magnetic rail is set on the ground, and flux from the magnetic rail is pinned by HTSCs. To increase levitation force, repulsive force of the permanent magnet is used. For the propulsion system, electromagnets are installed on the surface of the magnetic rail. Improvement of the propulsion force is studied. In the previous system, only flux of the permanent magnet of the carrier is used for propulsion. To increase propulsion force, that of the HTSC of the carrier is also used. Using this excitation method, the propulsion force is improved even though total number of the excited coil is the same.

  13. Investigation of a tubular dual-stator flux-switching permanent-magnet linear generator for free-piston energy converter

    NASA Astrophysics Data System (ADS)

    Sui, Yi; Zheng, Ping; Tong, Chengde; Yu, Bin; Zhu, Shaohong; Zhu, Jianguo

    2015-05-01

    This paper describes a tubular dual-stator flux-switching permanent-magnet (PM) linear generator for free-piston energy converter. The operating principle, topology, and design considerations of the machine are investigated. Combining the motion characteristic of free-piston Stirling engine, a tubular dual-stator PM linear generator is designed by finite element method. Some major structural parameters, such as the outer and inner radii of the mover, PM thickness, mover tooth width, tooth width of the outer and inner stators, etc., are optimized to improve the machine performances like thrust capability and power density. In comparison with conventional single-stator PM machines like moving-magnet linear machine and flux-switching linear machine, the proposed dual-stator flux-switching PM machine shows advantages in higher mass power density, higher volume power density, and lighter mover.

  14. Enforcement of Levitation Force by Capturing Magnetic Flux between YBa2Cu3O7-x Superconductor Bulk and Permanent Magnet

    NASA Astrophysics Data System (ADS)

    Song, Daniel; Jang, Hyungkwan; Kim, Se Bin; Han, Young Hee; Park, Byung Jun; Sung, Tae Hyun

    2012-09-01

    An iron block was placed on a permanent magnet (PM) as a path to capture the magnetic flux between a high-temperature superconductor (HTS) bulk and a PM. The effects of the magnetic flux for different iron block thicknesses (0, 2, 4, and 6 mm), configurations, and dimensions were experimentally determined. The optimal conditions for increasing the levitation force, which increased with decreasing air gap between the iron block and the PM, and with increasing iron block thickness, were determined. As the area of the iron block decreased, the levitation force increased, reaching a saturation point. Some iron block configurations acted as a path to capture the magnetic flux, and a higher levitation force was observed for a certain gap distance. Software simulation results support the obtained experimental results.

  15. Design of a transverse-flux permanent-magnet linear generator and controller for use with a free-piston stirling engine

    NASA Astrophysics Data System (ADS)

    Zheng, Jigui; Huang, Yuping; Wu, Hongxing; Zheng, Ping

    2016-06-01

    Transverse-flux with high efficiency has been applied in Stirling engine and permanent magnet synchronous linear generator system, however it is restricted for large application because of low and complex process. A novel type of cylindrical, non-overlapping, transverse-flux, and permanent-magnet linear motor(TFPLM) is investigated, furthermore, a high power factor and less process complexity structure research is developed. The impact of magnetic leakage factor on power factor is discussed, by using the Finite Element Analysis(FEA) model of stirling engine and TFPLM, an optimization method for electro-magnetic design of TFPLM is proposed based on magnetic leakage factor. The relation between power factor and structure parameter is investigated, and a structure parameter optimization method is proposed taking power factor maximum as a goal. At last, the test bench is founded, starting experimental and generating experimental are performed, and a good agreement of simulation and experimental is achieved. The power factor is improved and the process complexity is decreased. This research provides the instruction to design high-power factor permanent-magnet linear generator.

  16. Design of a transverse-flux permanent-magnet linear generator and controller for use with a free-piston stirling engine

    NASA Astrophysics Data System (ADS)

    Zheng, Jigui; Huang, Yuping; Wu, Hongxing; Zheng, Ping

    2016-07-01

    Transverse-flux with high efficiency has been applied in Stirling engine and permanent magnet synchronous linear generator system, however it is restricted for large application because of low and complex process. A novel type of cylindrical, non-overlapping, transverse-flux, and permanent-magnet linear motor(TFPLM) is investigated, furthermore, a high power factor and less process complexity structure research is developed. The impact of magnetic leakage factor on power factor is discussed, by using the Finite Element Analysis(FEA) model of stirling engine and TFPLM, an optimization method for electro-magnetic design of TFPLM is proposed based on magnetic leakage factor. The relation between power factor and structure parameter is investigated, and a structure parameter optimization method is proposed taking power factor maximum as a goal. At last, the test bench is founded, starting experimental and generating experimental are performed, and a good agreement of simulation and experimental is achieved. The power factor is improved and the process complexity is decreased. This research provides the instruction to design high-power factor permanent-magnet linear generator.

  17. Permanent-magnet-less machine having an enclosed air gap

    DOEpatents

    Hsu, John S.

    2013-03-05

    A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current. An uncluttered rotor disposed within the magnetic rotating field is spaced apart from the stator to form an air gap relative to an axis of rotation. A stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap substantially encloses the stationary excitation core. Some permanent magnet-less, brushless synchronous systems include stator core gaps to reduce axial flux flow. Some permanent magnet-less, brushless synchronous systems include an uncluttered rotor coupled to outer laminations. The quadrature-axis inductance may be increased in some synchronous systems. Some synchronous systems convert energy such as mechanical energy into electrical energy (e.g., a generator); other synchronous systems may convert any form of energy into mechanical energy (e.g., a motor).

  18. Permanent-magnet-less machine having an enclosed air gap

    DOEpatents

    Hsu, John S.

    2012-02-07

    A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current. An uncluttered rotor disposed within the magnetic rotating field is spaced apart from the stator to form an air gap relative to an axis of rotation. A stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap substantially encloses the stationary excitation core. Some permanent magnet-less, brushless synchronous systems include stator core gaps to reduce axial flux flow. Some permanent magnet-less, brushless synchronous systems include an uncluttered rotor coupled to outer laminations. The quadrature-axis inductance may be increased in some synchronous systems. Some synchronous systems convert energy such as mechanical energy into electrical energy (e.g., a generator); other synchronous systems may convert any form of energy into mechanical energy (e.g., a motor).

  19. SO2 flux monitoring at Stromboli with the new permanent INGV SO2 camera system: A comparison with the FLAME network and seismological data

    NASA Astrophysics Data System (ADS)

    Burton, M. R.; Salerno, G. G.; D'Auria, L.; Caltabiano, T.; Murè, F.; Maugeri, R.

    2015-07-01

    We installed a permanent SO2 camera system on Stromboli, Italy, in May 2013, in order to improve our capacity to monitor the SO2 emissions from this volcano. The camera collects images of SO2 concentrations with a period of ~ 10 s, allowing quantification of short-term processes, such as the gas released during the frequent explosions which are synonymous with Stromboli. It also allows quantification of the quiescent gas flux, and therefore comparison with the FLAME network of scanning ultraviolet spectrometers previously installed on the island. Analysis of results from the SO2 camera demonstrated a good agreement with the FLAME network when the plume was blown fully into the field of view of the camera. Permanent volcano monitoring with SO2 cameras is still very much in its infancy, and therefore this finding is a significant step in the use of such cameras for monitoring, whilst also highlighting the requirement of a favourable wind direction and strength. We found that the explosion gas emissions are correlated with seismic events which have a very long period component. There is a variable time lag between event onset time and the increase in gas flux observed by the camera as the explosion gas advects into the field of view of the camera. This variable lag is related to the plume direction, as shown by comparison with the plume location detected with the FLAME network. The correlation between explosion gas emissions and seismic signal amplitude show is consistent with a gas slug-driven mechanism for seismic event production. Comparison of the SO2 camera measurements of the quiescent gas flux shows a fair quantitative agreement with the SO2 flux measured with the FLAME network. Overall, the SO2 camera complements the FLAME network well, as it allows frequent quantification of the explosion gas flux produced by Stromboli, whose signal is in general too brief to be measured with the FLAME network. Further work is required, however, to fully automate the

  20. Validation of absolute axial neutron flux distribution calculations with MCNP with 197Au(n,γ)198Au reaction rate distribution measurements at the JSI TRIGA Mark II reactor.

    PubMed

    Radulović, Vladimir; Štancar, Žiga; Snoj, Luka; Trkov, Andrej

    2014-02-01

    The calculation of axial neutron flux distributions with the MCNP code at the JSI TRIGA Mark II reactor has been validated with experimental measurements of the (197)Au(n,γ)(198)Au reaction rate. The calculated absolute reaction rate values, scaled according to the reactor power and corrected for the flux redistribution effect, are in good agreement with the experimental results. The effect of different cross-section libraries on the calculations has been investigated and shown to be minor. PMID:24316530

  1. Permanent-Magnet Meissner Bearing

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    1994-01-01

    Permanent-magnet meissner bearing features inherently stable, self-centering conical configuration. Bearing made stiffer or less stiff by selection of magnets, springs, and spring adjustments. Cylindrical permanent magnets with axial magnetization stacked coaxially on rotor with alternating polarity. Typically, rare-earth magnets used. Magnets machined and fitted together to form conical outer surface.

  2. Research on a novel high stiffness axial passive magnetic bearing for DGMSCMG

    NASA Astrophysics Data System (ADS)

    Sun, Jinji; Wang, Chun'e.; Le, Yun

    2016-08-01

    To increase the displacement stiffness and decrease power loss of double gimbals magnetically suspended control momentum gyro (DGMSCMG), this paper researches a new structure of axial passive magnetic bearing (APMB). Different from the existing APMB, the proposed APMB is composed of segmented permanent magnets and magnetic rings. The displacement stiffness and angular stiffness expressions are derived by equivalent magnetic circuit method and infinitesimal method based on the end magnetic flux. The relationships are analyzed between stiffness and structure parameters such as length of air gap, length of permanent magnet, height of permanent magnet and end length of magnetic ring. Besides, the axial displacement stiffness measurement method of the APMB is proposed, and it verified the correctness of proposed theoretical method. The DGMSCMG prototype is manufactured and the slow-down characteristic experiment is carried out, and the experimental result reflects the low power loss feature of the APMB.

  3. Microstructure, Physical Properties, and Magnetic Flux Density Analysis of Permanent Magnet BaFe12O19 using Milling and Sintering Preparation Methods

    NASA Astrophysics Data System (ADS)

    Sardjono, Priyo; Suprapedi; Muljadi; Rusnaeni Djauhari, Nenen

    2016-08-01

    The purpose of this experiment is to analyze the influence of sintering temperature to the microstructure, physical, and magnetic properties of BaFe12O19 materials. The permanent magnet BaFe12O19 was made by using milling and sintering method, BaFe12O19 commercial powder was used as the raw material in this experiment. The raw material was pulverized by using ball mill for 15 hours and compacted at 400 MPa pressure to obtain a 16mm diameter and 4mm thick pellet. The pellet was sintered with 10oC/minute heating rate at various temperature ranges of 1050, 1100, 1150, and 1200oC for 1 hour. The microstructure and particle size of the pellet was investigated using XRD, SEM, and Particle Size Analyzer (PSA). The result shows that the milled powder has hexagonal BaFe12O19 crystal structure as the dominant phase, inhomogeneous size and shape of the grains, and average particle size is 19.60 pm. The bulk density measurement, shrinkage, and magnetic properties of the sintered samples were being observed and analyzed. It was found through this experiment that the optimum sintering temperature is 1150oC to obtain optimum bulk density (4.71 g/cm3), constant shrinkage (12.07%), 550 Gauss magnetic flux density, 1.79 kGauss remanence Br, and 1.75 kOe coercivity.

  4. Self-Centering Reciprocating-Permanent-Magnet Machine

    NASA Technical Reports Server (NTRS)

    Bhate, Suresh; Vitale, Nick

    1988-01-01

    New design for monocoil reciprocating-permanent-magnet electric machine provides self-centering force. Linear permanent-magnet electrical motor includes outer stator, inner stator, and permanent-magnet plunger oscillateing axially between extreme left and right positions. Magnets arranged to produce centering force and allows use of only one coil of arbitrary axial length. Axial length of coil chosen to provide required efficiency and power output.

  5. Axial Skeleton

    MedlinePlus

    ... Site-specific Modules Resources Archived Modules Updates Axial Skeleton (80 bones) Skull (28) Cranial Bones Parietal (2) ... Sternum (1) Ribs (24) « Previous (Divisions of the Skeleton) Next (Appendicular Skeleton (126 bones)) » Contact Us | Privacy ...

  6. Axial Pump

    NASA Technical Reports Server (NTRS)

    Bozeman, Richard J., Jr. (Inventor); Akkerman, James W. (Inventor); Aber, Gregory S. (Inventor); VanDamm, George Arthur (Inventor); Bacak, James W. (Inventor); Svejkovsky, Paul A. (Inventor); Benkowski, Robert J. (Inventor)

    1997-01-01

    A rotary blood pump includes a pump housing for receiving a flow straightener, a rotor mounted on rotor bearings and having an inducer portion and an impeller portion, and a diffuser. The entrance angle, outlet angle, axial and radial clearances of blades associated with the flow straightener, inducer portion, impeller portion and diffuser are optimized to minimize hemolysis while maintaining pump efficiency. The rotor bearing includes a bearing chamber that is filled with cross-linked blood or other bio-compatible material. A back emf integrated circuit regulates rotor operation and a microcomputer may be used to control one or more back emf integrated circuits. A plurality of magnets are disposed in each of a plurality of impeller blades with a small air gap. A stator may be axially adjusted on the pump housing to absorb bearing load and maximize pump efficiency.

  7. Axial superchargers

    NASA Technical Reports Server (NTRS)

    Betz, A

    1944-01-01

    Improvements, however, have been attained which permit a shortening of the structure without any impairment of the efficiency. The axial supercharger has a better efficiency and a simpler design than the radial supercharger. The relatively narrow range in which it operates satisfactorily should not be a very disturbing factor for practical flight problems. The length of this type of supercharger may be reduced considerably if some impairment in the efficiency is permitted.

  8. Permanent Magnetic Bearing for Spacecraft Applications

    NASA Technical Reports Server (NTRS)

    Morales, Winfredo; Fusaro, Robert; Kascak, Albert

    2008-01-01

    A permanent, totally passive magnetic bearing rig was designed, constructed, and tested. The suspension of the rotor was provided by two sets of radial permanent magnetic bearings operating in the repulsive mode. The axial support was provided by jewel bearings on both ends of the rotor. The rig was successfully operated to speeds of 5500 rpm using an air impeller. Radial and axial stiffnesses of the permanent magnetic bearings were experimentally measured and then compared to finite element results. The natural damping of the rotor was measured and a damping coefficient was calculated.

  9. Novel Integrated Radial and Axial Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A.; Brown, Gary L.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    Typically, fully active magnetically suspended systems require one axial and two radial magnetic bearings. Combining radial and axial functions into a single device allows for more compact and elegant packaging. Furthermore, in the case of high-speed devices such as energy storage flywheels, it is beneficial to minimize shaft length to keep rotor mode frequencies as high as possible. Attempts have been made to combine radial and axial functionality, but with certain drawbacks. One approach requires magnetic control flux to flow through a bias magnet reducing control effectiveness, thus resulting in increased resistive losses. This approach also requires axial force producing magnetic flux to flow in a direction into the rotor laminate that is undesirable for minimizing eddy-current losses resulting in rotational losses. Another approach applies a conical rotor shape to what otherwise would be a radial heteropolar magnetic bearing configuration. However, positional non-linear effects are introduced with this scheme and the same windings are used for bias, radial, and axial control adding complexity to the controller and electronics. For this approach, the amount of axial capability must be limited. It would be desirable for an integrated radial and axial magnetic bearing to have the following characteristics, separate inputs for radial and axial control for electronics and control simplicity, all magnetic control fluxes should only flow through their respective air gaps and should not flow through any bias magnets for minimal resistive losses, be of a homopolar design to minimize rotational losses, position related non-linear effects should be minimized, and dependent upon the design parameters, be able to achieve any radial/axial force or power ratio as desired. The integrated radial and axial magnetic bearing described in this paper exhibits all these characteristics. Magnetic circuit design, design equations, and analysis results will be presented.

  10. Magnetic bearing. [for supplying magnetic fluxes

    NASA Technical Reports Server (NTRS)

    Studer, P. A. (Inventor)

    1975-01-01

    A magnetic bearing is described which includes a pair of coaxial, toroidal, and permanent magnets having axially directed poles. Like poles of the permanent magnets are adjacent to each other, whereby the permanent magnets have a tendency to be urged apart along the common axis. An electromagnet is wound coaxially with the permanent magnets in such a manner that the poles are axially directed. Between the poles of each permanent magnet there is a low magnetic reluctance circuit including two series air gaps. Between the poles of the electromagnet a low reluctance path including only one air gap of each of the low magnetic reluctance circuits is provided. The low reluctance path for the electromagnet includes a ring axially translatable relative to the permanent magnets. The ring forms opposite faces of the air gaps in the magnetic circuits for each permanent magnet.

  11. Permanent magnet energy conversion machine with magnet mounting arrangement

    SciTech Connect

    Hsu, John S.; Adams, Donald J.

    1999-01-01

    A hybrid permanent magnet dc motor includes three sets of permanent magnets supported by the rotor and three sets of corresponding stators fastened to the surrounding frame. One set of magnets operates across a radial gap with a surrounding radial gap stator, and the other two sets of magnets operate off the respective ends of the rotor across respective axial gaps.

  12. Effective step-skew method for cogging torque reduction in surface-mounted permanent magnet synchronous motor

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Woo; Chang, Jung-Hwan

    2013-08-01

    This paper suggests an effective step-skew method to reduce the cogging torque of a surface-mounted permanent magnet synchronous motor (SPMSM). The main concept of the proposed method is to adjust each step length by considering the non-uniform air gap flux density distribution in the axial direction. The results show that the proposed step-skew method reduces the net cogging torque compared with the conventional step-skew method and is more effective for smaller stacking lengths and larger skew steps.

  13. Development of a compact permanent magnet helicon plasma source for ion beam bioengineering

    SciTech Connect

    Kerdtongmee, P.; Srinoum, D.; Nisoa, M.

    2011-10-15

    A compact helicon plasma source was developed as a millimeter-sized ion source for ion beam bioengineering. By employing a stacked arrangement of annular-shaped permanent magnets, a uniform axial magnetic flux density up to 2.8 kG was obtained. A cost effective 118 MHz RF generator was built for adjusting forward output power from 0 to 40 W. The load impedance and matching network were then analyzed. A single loop antenna and circuit matching elements were placed on a compact printed circuit board for 50 {Omega} impedance matching. A plasma density up to 1.1 x 10{sup 12} cm{sup -3} in the 10 mm diameter tube under the magnetic flux density was achieved with 35 W applied RF power.

  14. Development of a compact permanent magnet helicon plasma source for ion beam bioengineering.

    PubMed

    Kerdtongmee, P; Srinoum, D; Nisoa, M

    2011-10-01

    A compact helicon plasma source was developed as a millimeter-sized ion source for ion beam bioengineering. By employing a stacked arrangement of annular-shaped permanent magnets, a uniform axial magnetic flux density up to 2.8 kG was obtained. A cost effective 118 MHz RF generator was built for adjusting forward output power from 0 to 40 W. The load impedance and matching network were then analyzed. A single loop antenna and circuit matching elements were placed on a compact printed circuit board for 50 Ω impedance matching. A plasma density up to 1.1 × 10(12) cm(-3) in the 10 mm diameter tube under the magnetic flux density was achieved with 35 W applied RF power. PMID:22047290

  15. Essure Permanent Birth Control

    MedlinePlus

    ... Implants and Prosthetics Essure Permanent Birth Control Essure Permanent Birth Control Share Tweet Linkedin Pin it More sharing options ... evaluation of the Essure System Essure is a permanent birth control method for women (female sterilization). Implantation of Essure ...

  16. Axial-field permanent magnet motors for electric vehicles

    NASA Technical Reports Server (NTRS)

    Campbell, P.

    1981-01-01

    The modelling of an anisotropic alnico magnet for the purpose of field computation involves assigning a value for the material's permeability in the transverse direction. This is generally based upon the preferred direction properties, being all that are easily available. By analyzing the rotation of intrinsic magnetization due to the self demagnetizing field, it is shown that the common assumptions relating the transverse to the preferred direction are not accurate. Transverse magnetization characteristics are needed, and these are given for Alnico 5, 5-7, and 8 magnets, yielding appropriate permeability values.

  17. Permanent-magnet multipole with adjustable strength

    DOEpatents

    Halbach, K.

    1982-09-20

    Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling there between. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

  18. Permanent magnet multipole with adjustable strength

    DOEpatents

    Halbach, Klaus

    1985-01-01

    Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling therebetween. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

  19. BWR AXIAL PROFILE

    SciTech Connect

    J. Huffer

    2004-09-28

    The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips. Thus, accounting for axially varying burnup in criticality analyses is also referred to as accounting for the ''end effect'' reactivity. The magnitude of the reactivity change due to ''end effect'' is dependent on the initial assembly enrichment, the assembly average burnup, and the particular axial profile characterizing the burnup distribution. The set of bounding axial profiles should incorporate multiple BWR core designs and provide statistical confidence (95 percent confidence that 95 percent of the population is bound by the profile) that end nodes are conservatively represented. The profiles should also conserve the overall burnup of the fuel assembly. More background on BWR axial profiles is provided in Attachment I.

  20. Measuring axial pump thrust

    DOEpatents

    Suchoza, B.P.; Becse, I.

    1988-11-08

    An apparatus for measuring the hydraulic axial thrust of a pump under operation conditions is disclosed. The axial thrust is determined by forcing the rotating impeller off of an associated thrust bearing by use of an elongate rod extending coaxially with the pump shaft. The elongate rod contacts an impeller retainer bolt where a bearing is provided. Suitable measuring devices measure when the rod moves to force the impeller off of the associated thrust bearing and the axial force exerted on the rod at that time. The elongate rod is preferably provided in a housing with a heat dissipation mechanism whereby the hot fluid does not affect the measuring devices. 1 fig.

  1. Measuring axial pump thrust

    DOEpatents

    Suchoza, Bernard P.; Becse, Imre

    1988-01-01

    An apparatus for measuring the hydraulic axial thrust of a pump under operation conditions is disclosed. The axial thrust is determined by forcing the rotating impeller off of an associated thrust bearing by use of an elongate rod extending coaxially with the pump shaft. The elongate rod contacts an impeller retainer bolt where a bearing is provided. Suitable measuring devices measure when the rod moves to force the impeller off of the associated thrust bearing and the axial force exerted on the rod at that time. The elongate rod is preferably provided in a housing with a heat dissipation mechanism whereby the hot fluid does not affect the measuring devices.

  2. High temperature superconducting axial field magnetic coupler: realization and test

    NASA Astrophysics Data System (ADS)

    Belguerras, L.; Mezani, S.; Lubin, T.; Lévêque, J.; Rezzoug, A.

    2015-09-01

    Contactless torque transmission through a large airgap is required in some industrial applications in which hermetic isolation is necessary. This torque transmission usually uses magnetic couplers, whose dimension strongly depends on the airgap flux density. The use of high temperature superconducting (HTS) coils to create a strong magnetic field may constitute a solution to reduce the size of the coupler. It is also possible to use this coupler to replace a torque tube in transmitting the torque produced by a HTS motor to its load. This paper presents the detailed construction and tests of an axial field HTS magnetic coupler. Pancake coils have been manufactured from BSCCO tape and used in one rotor of the coupler. The second rotor is mainly composed of NdFeB permanent magnets. Several tests have been carried out showing that the constructed coupler is working properly. A 3D finite element (FE) model of the studied coupler has been developed. Airgap magnetic field and torque measurements have been carried out and compared to the FE results. It has been shown that the measured and the computed quantities are in satisfactory agreement.

  3. Rare earth permanent magnets

    SciTech Connect

    Major-Sosias, M.A.

    1993-10-01

    Permanent magnets were discovered centuries ago from what was known as {open_quotes}lodestone{close_quotes}, a rock containing large quantities of the iron-bearing mineral magnetite (Fe{sub 3}O{sub 4}). The compass was the first technological use for permanent magnetic materials; it was used extensively for navigational purposes by the fifteenth century. During the twentieth century, as new applications for permanent magnets were developed, interest and research in permanent magnetic materials soared. Four major types of permanent magnets have been developed since the turn of the century.

  4. Axial Halbach Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2008-01-01

    Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

  5. Axial static mixer

    DOEpatents

    Sandrock, H.E.

    1982-05-06

    Static axial mixing apparatus includes a plurality of channels, forming flow paths of different dimensions. The axial mixer includes a flow adjusting device for adjustable selective control of flow resistance of various flow paths in order to provide substantially identical flows through the various channels, thereby reducing nonuniform coating of interior surfaces of the channels. The flow adjusting device may include diaphragm valves, and may further include a pressure regulating system therefor.

  6. Performance of a Permanent-Magnet Cylindrical Hall-Effect Thruster

    NASA Technical Reports Server (NTRS)

    Polzin, K. A.; Sooby, E. S.; Kimberlin, A. C.; Raites, Y.; Merino, E.; Fisch, N. J.

    2009-01-01

    The performance of a low-power cylindrical Hall thruster, which more readily lends itself to miniaturization and low-power operation than a conventional (annular) Hall thruster, was measured using a planar plasma probe and a thrust stand. The field in the cylindrical thruster was produced using permanent magnets, promising a power reduction over previous cylindrical thruster iterations that employed electromagnets to generate the required magnetic field topology. Two sets of ring-shaped permanent magnets are used, and two different field configurations can be produced by reorienting the poles of one magnet relative to the other. A plasma probe measuring ion flux in the plume is used to estimate the current utilization for the two magnetic topologies. The measurements indicate that electron transport is impeded much more effectively in one configuration, implying higher thrust efficiency. Thruster performance measurements on this configuration were obtained over a power range of 70-350 W and with the cathode orifice located at three different axial positions relative to the thruster exit plane. The thrust levels over this power range were 1.25-6.5 mN, with anode efficiencies and specific impulses spanning 4-21% and 400-1950 s, respectively. The anode efficiency of the permanent-magnet thruster compares favorable with the efficiency of the electromagnet thruster when the power consumed by the electromagnets is taken into account.

  7. Permanent contraception for women.

    PubMed

    Micks, Elizabeth A; Jensen, Jeffrey T

    2015-11-01

    Permanent methods of contraception are used by an estimated 220 million couples worldwide, and are often selected due to convenience, ease of use and lack of side effects. A variety of tubal occlusion techniques are available for female permanent contraception, and procedures can be performed using a transcervical or transabdominal approach. This article reviews currently available techniques for female permanent contraception and discusses considerations when helping patients choose a contraceptive method and tubal occlusion technique.

  8. Effect of Side Permanent Magnets for Reluctance Interior Permanent Magnet Reluctance Machines

    SciTech Connect

    Hsu, John S; Lee, Seong T; Wiles, Randy H; Coomer, Chester; Lowe, Kirk T

    2007-01-01

    A traditional electric machine uses two dimensional magnetic flux paths in its rotor. This paper presents the development work on the utilization of the third dimension of a rotor. As an example, the air gap flux of a radial gap interior permanent magnet motor can be significantly enhanced by additional permanent magnets (PM) mounted at the sides of the rotor. A prototype motor built with this concept provided higher efficiency and required a shorter stator core length for the same power output as the Toyota/Prius traction drive motor.

  9. Cylindrical Hall Thrusters with Permanent Magnets

    SciTech Connect

    Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.

    2010-10-18

    The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT. __________________________________________________

  10. Force prediction in permanent magnet flat linear motors (abstract)

    NASA Astrophysics Data System (ADS)

    Eastham, J. F.; Akmese, R.

    1991-11-01

    The advent of neodymium iron boron rare-earth permanent magnet material has afforded the opportunity to construct linear machines of high force to weight ratio. The paper describes the design and construction of an axial flux machine and rotating drum test rig. The machine occupies an arc of 45° on a drum 1.22 m in diameter. The excitation is provided by blocks of NdFeB material which are skewed in order to minimize the force variations due to slotting. The stator carries a three-phase short-chorded double-layer winding of four poles. The machine is supplied by a PWM inverter the fundamental component of which is phase locked to the rotor position so that a ``dc brushless'' drive system is produced. Electromagnetic forces including ripple forces are measured at supply frequencies up to 100 Hz. They are compared with finite-element analysis which calculates the force variation over the time period. The paper then considers some of the causes of ripple torque. In particular, the force production due solely to the permanent magnet excitation is considered. This has two important components each acting along the line of motion of the machine, one is due to slotting and the other is due to the finite length of the primary. In the practical machine the excitation poles are skewed to minimize the slotting force and the effectiveness of this is confirmed by both results from the experiments and the finite-element analysis. The end effect force is shown to have a space period of twice that of the excitation. The amplitude of this force and its period are again confirmed by practical results.

  11. Characterization of superconducting magnetic bearings (dynamic stiffness and damping coefficient in axial direction)

    NASA Technical Reports Server (NTRS)

    Takahata, Ryoichi; Ueyama, Hirochika; Yotsuya, Tsutom

    1992-01-01

    High T(sub c) superconductor as a stator and permanent magnets for a rotor were assembled into a superconducting magnetic bearing. The dynamic stiffness and the damping coefficient of the superconducting magnetic bearing in axial direction were measured. The dynamic stiffness depended on an axial gap between superconductor and permanent magnet. The superconducting magnetic bearings are advantageous for a passive bearing, because they have a vibration damping effect that a permanent magnet bearing does not have. The tendency of its vibration damping coefficient indicated an increase as the resonant frequency increased.

  12. Altered Axial Skeletal Development

    EPA Science Inventory

    The axial skeleton is routinely examined in standard developmental toxicity bioassays and has proven to be sensitive to a wide variety of chemical agents. Dysmorphogenesis in the skull, vertebral column and ribs has been described in both human populations and in laboratory anima...

  13. Permanent magnet assembly

    DOEpatents

    Chell, Jeremy; Zimm, Carl B.

    2006-12-12

    A permanent magnet assembly is disclosed that is adapted to provide a magnetic field across an arc-shaped gap. Such a permanent magnet assembly can be used, for example, to provide a time-varying magnetic field to an annular region for use in a magnetic refrigerator.

  14. A Model for Axial Magnetic Bearings Including Eddy Currents

    NASA Technical Reports Server (NTRS)

    Kucera, Ladislav; Ahrens, Markus

    1996-01-01

    This paper presents an analytical method of modelling eddy currents inside axial bearings. The problem is solved by dividing an axial bearing into elementary geometric forms, solving the Maxwell equations for these simplified geometries, defining boundary conditions and combining the geometries. The final result is an analytical solution for the flux, from which the impedance and the force of an axial bearing can be derived. Several impedance measurements have shown that the analytical solution can fit the measured data with a precision of approximately 5%.

  15. Sedimentation at the permanently ice-covered Greenland continental shelf (74°57.7‧N/12°58.7‧W): significance of biogenic and lithogenic particles in particulate matter flux

    NASA Astrophysics Data System (ADS)

    Bauerfeind, Eduard; Leipe, Thomas; Ramseier, Rene O.

    2005-05-01

    Particle flux was recorded at the Greenland continental shelf at a water depth of 245 m from July 1994 to August 1995. The annual total matter flux amounted to 51.8 g m -2. Of this total flux, 14.4 g m -2 could be ascribed to carbonate (CaCO 3) and 3.05 and 2.06 g m -2 to refractory particulate organic carbon (rPOC) and biological silica (bPSI), respectively. About the same contribution of biogenic (48%) and lithogenic (52%) matter to total flux was measured during the mooring period. However, when split up into seasons, biogenic matter predominated during the summer (May-September) (58%) and particles of lithogenic origin prevailed in winter (October-April) 73%. Within the recognizable biogenic fraction, diatoms ( Fragilaropsis sp., Chaetoceros sp.) predominated. Ice-related material certainly also contributed to vertical particle flux in July-September, as indicated by the occurrence of ice-associated algae, i.e. Melosira arctica, in the samples. The δ15N signature of the particulate matter indicated a substantial contribution of freshly produced organic matter to the sedimented particle pool during the times of elevated bPSi and diatom flux. Clay minerals dominated within the lithogenic fraction year round (66%), with illite being the most prominent mineral (50%) followed by chlorite (27%), smectite (12%) and kaolinite (7%). Significantly larger (71%) contributions of clay minerals on lithogenic matter flux were noticed during summer than in winter (53%). No clear distinction of the possible origin of the lithogenic matter (<20 μm) in the trap samples can be made as the ice-transported lithogenic matter and composition of the surface sediments at the shelf show a similar composition. However, from the concomitant increase of biogenic matter, ice-associated algae and clay minerals in the trap samples during summer, we also deduce a substantial supply of ice-released lithogenic matter during this period. We conclude that the simultaneous occurrence of biogenic

  16. On the Motion of the Field of a Permanent Magnet

    ERIC Educational Resources Information Center

    Leus, Vladimir; Taylor, Stephen

    2011-01-01

    A description is given of a series of recent experiments using a rotating magnetic circuit comprising a permanent magnet ring and yoke, and a stationary conductor in the air gap between the ring and yoke. The EMF induced in this case cannot be described by a simple application of Faraday's flux law. This is because the magnetic flux in the air gap…

  17. Surface nanoscale axial photonics.

    PubMed

    Sumetsky, M; Fini, J M

    2011-12-19

    Dense photonic integration promises to revolutionize optical computing and communications. However, efforts towards this goal face unacceptable attenuation of light caused by surface roughness in microscopic devices. Here we address this problem by introducing Surface Nanoscale Axial Photonics (SNAP). The SNAP platform is based on whispering gallery modes circulating around the optical fiber surface and undergoing slow axial propagation readily described by the one-dimensional Schrödinger equation. These modes can be steered with dramatically small nanoscale variation of the fiber radius, which is quite simple to introduce in practice. Extremely low loss of SNAP devices is achieved due to the low surface roughness inherent in a drawn fiber surface. In excellent agreement with the developed theory, we experimentally demonstrate localization of light in quantum wells, halting light by a point source, tunneling through potential barriers, dark states, etc. This demonstration has intriguing potential applications in filtering, switching, slowing light, and sensing.

  18. Magnetic flux leakage inspection of gas pipelines: The effects of remanent magnetization. Topical report, 1992-1994

    SciTech Connect

    Nestleroth, J.B.; Davis, R.J.

    1995-04-01

    The Magnetic Flux Leakage (MFL) Technique is the most commonly used technique to inspect large diameter transmission pipelines. A typical MFL inspection system uses permanent magnets to apply an axially oriented magnetic field to the ferromagnetic pipe material. Remanent magnetization affects the applied-magnetization because pipleline steels have sufficient retentivity to influence the magnetization of subsequent inspections. The remanent magnetization affects detection and characterization of pipeline corrosion in two ways. First, remanent magnetization changes the strength of the applied field level for subsequent inspection runs. Second, the remanent magnetization changes the flux leakage from corrosion defects, which affects defect detection and characterization of the defect geometry. Experimental data obtained from the GRI Pipeline Simulation Facility are used to illustrate the effect of remanent magnetization on flux leakage inspections.

  19. Axial Plane Optical Microscopy

    PubMed Central

    Li, Tongcang; Ota, Sadao; Kim, Jeongmin; Wong, Zi Jing; Wang, Yuan; Yin, Xiaobo; Zhang, Xiang

    2014-01-01

    We present axial plane optical microscopy (APOM) that can, in contrast to conventional microscopy, directly image a sample's cross-section parallel to the optical axis of an objective lens without scanning. APOM combined with conventional microscopy simultaneously provides two orthogonal images of a 3D sample. More importantly, APOM uses only a single lens near the sample to achieve selective-plane illumination microscopy, as we demonstrated by three-dimensional (3D) imaging of fluorescent pollens and brain slices. This technique allows fast, high-contrast, and convenient 3D imaging of structures that are hundreds of microns beneath the surfaces of large biological tissues. PMID:25434770

  20. Axial Plane Optical Microscopy

    NASA Astrophysics Data System (ADS)

    Li, Tongcang; Ota, Sadao; Kim, Jeongmin; Wong, Zi Jing; Wang, Yuan; Yin, Xiaobo; Zhang, Xiang

    2014-12-01

    We present axial plane optical microscopy (APOM) that can, in contrast to conventional microscopy, directly image a sample's cross-section parallel to the optical axis of an objective lens without scanning. APOM combined with conventional microscopy simultaneously provides two orthogonal images of a 3D sample. More importantly, APOM uses only a single lens near the sample to achieve selective-plane illumination microscopy, as we demonstrated by three-dimensional (3D) imaging of fluorescent pollens and brain slices. This technique allows fast, high-contrast, and convenient 3D imaging of structures that are hundreds of microns beneath the surfaces of large biological tissues.

  1. Highest permanent human habitation.

    PubMed

    West, John B

    2002-01-01

    The aim of this analysis was to determine the altitude of the highest permanent human habitation in the hope that this will throw some light on what determines the highest altitude that a community can tolerate indefinitely. A number of places where people have lived at very high altitudes for long periods of time are reviewed. Individuals have lived for as long as 2 yr at an altitude of 5950 m, and there was a miner's camp at 5300 m for several years. The highest permanently inhabited town in the world at the present time appears to be La Rinconada, a mining village of over 7000 people in southern Peru at an altitude of up to 5100 m, which has been in existence for over 40 yr. The altitude of the highest permanent human habitation is determined partly by economic factors, rather than solely by human tolerance to hypoxia. PMID:12631426

  2. GEOS axial booms

    NASA Technical Reports Server (NTRS)

    Schmidt, G. K.

    1979-01-01

    A booms and mechanisms subsystem was designed, developed, and qualified for the geostationary scientific satellite GEOS. Part of this subsystem consist of four axial booms consisting of one pair of 1 m booms and one pair of 2.5 m booms. Each of these booms is carrying one bird cage electric field sensor. Alignment accuracy requirements led to a telescopic type solution. Deployment is performed by pressurized nitrogen. At deployment in orbit two of these booms showed some anomalies and one of these two deployed only about 80%. Following this malfunction a detailed failure investigation was performed resulting in a design modification of some critical components as release mechanism, guide sleeves of the telescopic elements, and pressure system.

  3. Alkaline "Permanent" Paper.

    ERIC Educational Resources Information Center

    Pacey, Antony

    1991-01-01

    Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and recyclability is…

  4. Axial movements in ideomotor apraxia

    PubMed Central

    Poeck, K; Lehmkuhl, G; Willmes, K

    1982-01-01

    Non-symbolic axial movements were examined and compared to oral and limb movements in a group of 60 aphasic patients (15 of each major subgroup) with exclusively left-sided brain damage. The contention in the literature that axial movements are preserved in patients with ideomotor limb apraxia was not confirmed. PMID:6186771

  5. Variable Permanent Magnet Quadrupole

    SciTech Connect

    Mihara, T.; Iwashita, Y.; Kumada, M.; Spencer, C.M.; /SLAC

    2007-05-23

    A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.

  6. Permanent Peripheral Neuropathy

    PubMed Central

    Higgins, Elizabeth

    2014-01-01

    The health risks and side effects of fluoroquinolone use include the risk of tendon rupture and myasthenia gravis exacerbation, and on August 15, 2013, the Food and Drug Administration updated its warning to include the risk of permanent peripheral neuropathy. We present a case of fluoroquinolone-induced peripheral neuropathy in a patient treated for clinically diagnosed urinary tract infection with ciprofloxacin antibiotic. PMID:26425618

  7. Permanent magnet design methodology

    NASA Technical Reports Server (NTRS)

    Leupold, Herbert A.

    1991-01-01

    Design techniques developed for the exploitation of high energy magnetically rigid materials such as Sm-Co and Nd-Fe-B have resulted in a revolution in kind rather than in degree in the design of a variety of electron guidance structures for ballistic and aerospace applications. Salient examples are listed. Several prototype models were developed. These structures are discussed in some detail: permanent magnet solenoids, transverse field sources, periodic structures, and very high field structures.

  8. Monocoil reciprocating permanent magnet electric machine with self-centering force

    NASA Technical Reports Server (NTRS)

    Bhate, Suresh K. (Inventor); Vitale, Nicholas G. (Inventor)

    1989-01-01

    A linear reciprocating machine has a tubular outer stator housing a coil, a plunger and an inner stator. The plunger has four axially spaced rings of radially magnetized permanent magnets which cooperate two at a time with the stator to complete first or second opposite magnetic paths. The four rings of magnets and the stators are arranged so that the stroke of the plunger is independent of the axial length of the coil.

  9. Axial gap rotating electrical machine

    DOEpatents

    None

    2016-02-23

    Direct drive rotating electrical machines with axial air gaps are disclosed. In these machines, a rotor ring and stator ring define an axial air gap between them. Sets of gap-maintaining rolling supports bear between the rotor ring and the stator ring at their peripheries to maintain the axial air gap. Also disclosed are wind turbines using these generators, and structures and methods for mounting direct drive rotating electrical generators to the hubs of wind turbines. In particular, the rotor ring of the generator may be carried directly by the hub of a wind turbine to rotate relative to a shaft without being mounted directly to the shaft.

  10. Intra-axial brain tumors.

    PubMed

    Rapalino, Otto; Batchelor, Tracy; González, R Gilberto

    2016-01-01

    There is a wide variety of intra-axial primary and secondary brain neoplasms. Many of them have characteristic imaging features while other tumors can present in a similar fashion. There are peculiar posttreatment imaging phenomena that can present as intra-axial mass-like lesions (such as pseudoprogression or radiation necrosis), further complicating the diagnosis and clinical follow-up of patients with intracerebral tumors. The purpose of this chapter is to present a general overview of the most common intra-axial brain tumors and peculiar posttreatment changes that are very important in the diagnosis and clinical follow-up of patients with brain tumors. PMID:27432670

  11. Axial Tilt Angles of Active Regions

    NASA Astrophysics Data System (ADS)

    Howard, Robert F.

    1996-12-01

    Separate Mount Wilson plage and sunspot group data sets are analyzed in this review to illustrate several interesting aspects of active region axial tilt angles. (1) The distribution of tilt angles differs between plages and sunspot groups in the sense that plages have slightly higher tilt angles, on average, than do spot groups. (2) The distributions of average plage total magnetic flux, or sunspot group area, with tilt angle show a consistent effect: those groups with tilt angles nearest the average values are larger (or have a greater total flux) on average than those farther from the average values. Moreover, the average tilt angles on which these size or flux distributions are centered differ for the two types of objects, and represent closely the actual different average tilt angles for these two features. (3) The polarity separation distances of plages and sunspot groups show a clear relationship to average tilt angles. In the case of each feature, smaller polarity separations are correlated with smaller tilt angles. (4) The dynamics of regions also show a clear relationship with region tilt angles. The spot groups with tilt angles nearest the average value (or perhaps 0-deg tilt angle) have on average a faster rotation rate than those groups with extreme tilt angles. All of these tilt-angle characteristics may be assumed to be related to the physical forces that affect the magnetic flux loop that forms the region. These aspects are discussed in this brief review within the context of our current view of the formation of active region magnetic flux at the solar surface.

  12. Liquids with permanent porosity.

    PubMed

    Giri, Nicola; Del Pópolo, Mario G; Melaugh, Gavin; Greenaway, Rebecca L; Rätzke, Klaus; Koschine, Tönjes; Pison, Laure; Gomes, Margarida F Costa; Cooper, Andrew I; James, Stuart L

    2015-11-12

    Porous solids such as zeolites and metal-organic frameworks are useful in molecular separation and in catalysis, but their solid nature can impose limitations. For example, liquid solvents, rather than porous solids, are the most mature technology for post-combustion capture of carbon dioxide because liquid circulation systems are more easily retrofitted to existing plants. Solid porous adsorbents offer major benefits, such as lower energy penalties in adsorption-desorption cycles, but they are difficult to implement in conventional flow processes. Materials that combine the properties of fluidity and permanent porosity could therefore offer technological advantages, but permanent porosity is not associated with conventional liquids. Here we report free-flowing liquids whose bulk properties are determined by their permanent porosity. To achieve this, we designed cage molecules that provide a well-defined pore space and that are highly soluble in solvents whose molecules are too large to enter the pores. The concentration of unoccupied cages can thus be around 500 times greater than in other molecular solutions that contain cavities, resulting in a marked change in bulk properties, such as an eightfold increase in the solubility of methane gas. Our results provide the basis for development of a new class of functional porous materials for chemical processes, and we present a one-step, multigram scale-up route for highly soluble 'scrambled' porous cages prepared from a mixture of commercially available reagents. The unifying design principle for these materials is the avoidance of functional groups that can penetrate into the molecular cage cavities. PMID:26560299

  13. Permanent soft tissue fillers.

    PubMed

    Wilson, YuShan L; Ellis, David A F

    2011-12-01

    As our youth-oriented society ages, interest in nonsurgical aesthetic techniques has generated a dramatic rise in the use of filling agents for facial rejuvenation. Backed by multiple published studies documenting safety and efficacy, soft tissue fillers are often viewed as treatments with minimal recovery time and limited risk of complications when compared with traditional surgical interventions. This has led to a genuine demand for fillers with similar safety profiles but ever increasing longevity in their aesthetic corrections. This review addresses many of the permanent soft tissue fillers that are commercially available worldwide as well as important concerns regarding their complications.

  14. High flux reactor

    DOEpatents

    Lake, James A.; Heath, Russell L.; Liebenthal, John L.; DeBoisblanc, Deslonde R.; Leyse, Carl F.; Parsons, Kent; Ryskamp, John M.; Wadkins, Robert P.; Harker, Yale D.; Fillmore, Gary N.; Oh, Chang H.

    1988-01-01

    A high flux reactor is comprised of a core which is divided into two symetric segments housed in a pressure vessel. The core segments include at least one radial fuel plate. The spacing between the plates functions as a coolant flow channel. The core segments are spaced axially apart such that a coolant mixing plenum is formed between them. A channel is provided such that a portion of the coolant bypasses the first core section and goes directly into the mixing plenum. The outlet coolant from the first core segment is mixed with the bypass coolant resulting in a lower inlet temperature to the lower core segment.

  15. Fluorescence axial nanotomography with plasmonics.

    PubMed

    Cade, Nicholas I; Fruhwirth, Gilbert O; Krasavin, Alexey V; Ng, Tony; Richards, David

    2015-01-01

    We present a novel imaging technique with super-resolution axial sensitivity, exploiting the changes in fluorescence lifetime above a plasmonic substrate. Using conventional confocal fluorescence lifetime imaging, we show that it is possible to deliver down to 6 nm axial position sensitivity of fluorophores in whole biological cell imaging. We employ this technique to map the topography of the cellular membrane, and demonstrate its application in an investigation of receptor-mediated endocytosis in carcinoma cells.

  16. Axial anomaly at arbitrary virtualities

    SciTech Connect

    Veretin, O.L.; Teryaev, O.V.

    1995-12-01

    The one-loop analytic expression for the axial-vector triangle diagram involving an anomaly is obtained for arbitrary virtualities of external momenta. The `t Hooft consistency principle is applied to the QCD sum rules for the first moment of the photon spin structure function g{sub l}{sup {gamma}}. It is shown that the contribution of the singlet axial current to the sum rules for g{sub l}{sup {gamma}} vanishes. 19 refs., 1 fig.

  17. Cryogenic Permanent Magnet Undulators

    SciTech Connect

    Chavanne, J.; Lebec, G.; Penel, C.; Revol, F.; Kitegi, C.

    2010-06-23

    For an in-vacuum undulator operated at small gaps the permanent magnet material needs to be highly resistant to possible electron beam exposure. At room temperature, one generally uses Sm{sub 2}Co{sub 17} or high coercivity NdFeB magnets at the expense of a limited field performance. In a cryogenic permanent magnet undulator (CPMU), at a temperature of around 150 K, any NdFeB grade reveals a coercivity large enough to be radiation resistant. In particular, very high remanence NdFeB material can be used to build undulators with enhanced field and X-ray brilliance at high photon energy provided that the pre-baking of the undulator above 100 deg. C can be eliminated. The ESRF has developed a full scale 2 m long CPMU with a period of 18 mm. This prototype has been in operation on the ID6 test beamline since January 2008. A significant effort was put into the characterization of NdFeB material at low temperature, the development of dedicated magnetic measurement systems and cooling methods. The measured heat budget with beam is found to be larger than expected without compromising the smooth operation of the device. Leading on from this first experience, new CPMUs are currently being considered for the upgrade of the ESRF.

  18. Globally Optimal Segmentation of Permanent-Magnet Systems

    NASA Astrophysics Data System (ADS)

    Insinga, A. R.; Bjørk, R.; Smith, A.; Bahl, C. R. H.

    2016-06-01

    Permanent-magnet systems are widely used for generation of magnetic fields with specific properties. The reciprocity theorem, an energy-equivalence principle in magnetostatics, can be employed to calculate the optimal remanent flux density of the permanent-magnet system, given any objective functional that is linear in the magnetic field. This approach, however, yields a continuously varying remanent flux density, while in practical applications, magnetic assemblies are realized by combining uniformly magnetized segments. The problem of determining the optimal shape of each of these segments remains unsolved. We show that the problem of optimal segmentation of a two-dimensional permanent-magnet assembly with respect to a linear objective functional can be reduced to the problem of piecewise linear approximation of a plane curve by perimeter maximization. Once the problem has been cast into this form, the globally optimal solution can be easily computed employing dynamic programming.

  19. Counterrotating brushless dc permanent magnet motor

    SciTech Connect

    Hawsey, R.A.; Bailey, J.M.

    1990-01-01

    An brushless DC permanent magnet motor is provided for driving an autonomous underwater vehicle. In one embodiment, the motor comprises four substantially flat stators disposed in stacked relationship, with pairs of the stators being axially spaced and each of the stators comprising a tape-wound stator coil; and a first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of permanent magnets embedded therein. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore therein in which the first shaft is disposed. Two different sets of bearings support the first and second shAfts. In another embodiment, the motor comprises two ironless stators and pairs and rotors mounted no opposite sides of the stators and driven by counterrotating shafts.

  20. Flux Compression Magnetic Nozzle

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

    2001-01-01

    In pulsed fusion propulsion schemes in which the fusion energy creates a radially expanding plasma, a magnetic nozzle is required to redirect the radially diverging flow of the expanding fusion plasma into a rearward axial flow, thereby producing a forward axial impulse to the vehicle. In a highly electrically conducting plasma, the presence of a magnetic field B in the plasma creates a pressure B(exp 2)/2(mu) in the plasma, the magnetic pressure. A gradient in the magnetic pressure can be used to decelerate the plasma traveling in the direction of increasing magnetic field, or to accelerate a plasma from rest in the direction of decreasing magnetic pressure. In principle, ignoring dissipative processes, it is possible to design magnetic configurations to produce an 'elastic' deflection of a plasma beam. In particular, it is conceivable that, by an appropriate arrangement of a set of coils, a good approximation to a parabolic 'magnetic mirror' may be formed, such that a beam of charged particles emanating from the focal point of the parabolic mirror would be reflected by the mirror to travel axially away from the mirror. The degree to which this may be accomplished depends on the degree of control one has over the flux surface of the magnetic field, which changes as a result of its interaction with a moving plasma.

  1. Achieving permanency for LGBTQ youth.

    PubMed

    Jacobs, Jill; Freundlich, Madelyn

    2006-01-01

    This article brings together two significant efforts in the child welfare field: achieving permanence for youth in out-of-home care and meeting the needs of lesbian, gay, bisexual, transgender and questioning (LGBTQ) youth. During the past several years, a national movement has taken place to assure all children and youth have a permanent family connection before leaving the child welfare system; however, LGBTQ youth are not routinely included in the permanency discussions. At the same time, efforts in addressing the needs of LGBTQ youth have increased, but permanency is rarely mentioned as a need. This article offers models of permanence and practices to facilitate permanence with LGBTQ youth and their families. It also offers a youth-driven, individualized process, using youth development principles to achieve relational, physical, and legal permanence. Reunification efforts are discussed, including services, supports, and education required for youth to return to their family of origin. For those who cannot return home, other family resources are explored. The article also discusses cultural issues as they affect permanence for LGBTQ youth, and, finally, addresses the need for ongoing support services to sustain and support permanency.

  2. Interior Permanent Magnet Reluctance Machine with Brushless Field Excitation

    SciTech Connect

    Wiles, R.H.

    2005-10-07

    In a conventional permanent magnet (PM) machine, the air-gap flux produced by the PM is fixed. It is difficult to enhance the air-gap flux density due to limitations of the PM in a series-magnetic circuit. However, the air-gap flux density can be weakened by using power electronic field weakening to the limit of demagnetization of the PMs. This paper presents the test results of controlling the PM air-gap flux density through the use of a stationary brushless excitation coil in a reluctance interior permanent magnet with brushless field excitation (RIPM-BFE) motor. Through the use of this technology the air-gap flux density can be either enhanced or weakened. There is no concern with demagnetizing the PMs during field weakening. The leakage flux of the excitation coil through the PMs is blocked. The prototype motor built on this principle confirms the concept of flux enhancement and weakening through the use of excitation coils.

  3. Compact Permanent Magnet Microwave-Driven Neutron Generator

    SciTech Connect

    Ji Qing

    2011-06-01

    Permanent magnet microwave-driven neutron generators have been developed at Lawrence Berkeley National Laboratory. The 2.45 GHz microwave signal is directly coupled into the plasma chamber via a microwave window. Plasma is confined in an axial magnetic field produced by the permanent magnets surrounding the plasma chamber. The source chamber is made of aluminum with a diameter of 4 cm and length of 5 cm. A stack of five alumina discs, which are 3 cm in diameter and total length of 3 cm, works as microwave window. Three permanent ring magnets are used to generate the axial magnetic field required for the microwave ion source. Both hydrogen and deuterium plasma have been successfully ignited. With 330W of microwave power, source chamber pressure of 5 mTorr, and an extraction aperture of 2 mm in diameter, the deuterium ion beam measured on the target was approximately 2.5 mA. Over 90% of the ions are atomic. With the ion source at ground potential and titanium target at -40 kV, the analysis of the activated gold foil and calibrated neutron dose monitor both indicated that roughly 10{sup 7} n/s of D-D neutrons have been produced. The D-D neutron yield can be easily scaled up to 10{sup 8} n/s when the titanium target is biased at -100 kV.

  4. Microwave electron cyclotron electron resonance (ECR) ion source with a large, uniformly distributed, axially symmetric, ECR plasma volume

    DOEpatents

    Alton, Gerald D.

    1996-01-01

    An electron cyclotron resonance (ECR) ion source includes a primary mirror coil disposed coaxially around a vacuum vessel in which a plasma is induced and introducing a solenoidal ECR-producing field throughout the length of the vacuum vessel. Radial plasma confinement is provided by a multi-cusp, multi-polar permanent magnet array disposed azimuthally around the vessel and within the primary mirror coil. Axial confinement is provided either by multi-cusp permanent magnets at the opposite axial ends of the vessel, or by secondary mirror coils disposed on opposite sides of the primary coil.

  5. Helical flux ropes in solar prominences

    NASA Technical Reports Server (NTRS)

    Martens, P. C. H.; Van Ballegooijen, A. A.

    1990-01-01

    The present numerical method for the computation of force-free, cancelling magnetic structures shows that flux cancellation at the neutral line in a sheared magnetic arcade generates helical field lines that can support a prominence's plasma. With increasing flux cancellation, the axis of the helical fields moves to greater heights; this is suggestive of a prominence eruption. Two alternative scenarios are proposed for the formation of polar crown prominences which yield the correct axial magnetic field sign. Both models are noted to retain the formation of helical flux tubes through flux cancellation as their key feature.

  6. Axial structure of the nucleon

    SciTech Connect

    Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner

    2002-01-01

    We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.

  7. ) Mold Fluxes

    NASA Astrophysics Data System (ADS)

    Seo, Myung-Duk; Shi, Cheng-Bin; Cho, Jung-Wook; Kim, Seon-Hyo

    2014-10-01

    The effects of basicity (CaO/SiO2), B2O3, and Li2O addition on the crystallization behaviors of lime-silica-based mold fluxes have been investigated by non-isothermal differential scanning calorimetry (DSC), field emission scanning electron microscopy, X-ray diffraction (XRD), and single hot thermocouple technique. It was found that the crystallization temperature of cuspidine increased with increasing the basicity of mold fluxes. The crystallization of wollastonite was suppressed with increasing the mold flux basicity due to the enhancement of cuspidine crystallization. The addition of B2O3 suppresses the crystallization of mold flux. The crystallization temperature of mold flux decreases with Li2O addition. The size of cuspidine increases, while the number of cuspidine decreases with increasing mold flux basicity. The morphology of cuspidine in mold fluxes with lower basicity is largely dendritic. The dendritic cuspidine in mold fluxes is composed of many fine cuspidine crystals. On the contrary, in mold fluxes with higher basicity, the cuspidine crystals are larger in size with mainly faceted morphology. The crystalline phase evolution was also calculated using a thermodynamic database, and compared with the experimental results determined by DSC and XRD. The results of thermodynamic calculation of crystalline phase formation are in accordance with the results determined by DSC and XRD.

  8. Disc rotors with permanent magnets for brushless DC motor

    DOEpatents

    Hawsey, Robert A.; Bailey, J. Milton

    1992-01-01

    A brushless dc permanent magnet motor drives an autonomous underwater vehe. In one embodiment, the motor comprises four substantially flat stators in stacked relationship, with pairs of the stators axially spaced, each of the stators comprising a tape-wound stator coil, and first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of permanent magnets embedded therein. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and a drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs of rotors mounted on opposite sides of the stators and driven by counterrotating shafts.

  9. Periodic permanent magnet focused klystron

    SciTech Connect

    Ferguson, Patrick; Read, Michael; Ives, R Lawrence

    2015-04-21

    A periodic permanent magnet (PPM) klystron has beam transport structures and RF cavity structures, each of which has permanent magnets placed substantially equidistant from a beam tunnel formed about the central axis, and which are also outside the extent of a cooling chamber. The RF cavity sections also have permanent magnets which are placed substantially equidistant from the beam tunnel, but which include an RF cavity coupling to the beam tunnel for enhancement of RF carried by an electron beam in the beam tunnel.

  10. Forced axial segregation in axially inhomogeneous rotating systems.

    PubMed

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

    2015-08-01

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

  11. Forced axial segregation in axially inhomogeneous rotating systems

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  12. Permanent Magnet Ecr Plasma Source With Magnetic Field Optimization

    DOEpatents

    Doughty, Frank C.; Spencer, John E.

    2000-12-19

    In a plasma-producing device, an optimized magnet field for electron cyclotron resonance plasma generation is provided by a shaped pole piece. The shaped pole piece adjusts spacing between the magnet and the resonance zone, creates a convex or concave resonance zone, and decreases stray fields between the resonance zone and the workpiece. For a cylindrical permanent magnet, the pole piece includes a disk adjacent the magnet together with an annular cylindrical sidewall structure axially aligned with the magnet and extending from the base around the permanent magnet. The pole piece directs magnetic field lines into the resonance zone, moving the resonance zone further from the face of the magnet. Additional permanent magnets or magnet arrays may be utilized to control field contours on a local scale. Rather than a permeable material, the sidewall structure may be composed of an annular cylindrical magnetic material having a polarity opposite that of the permanent magnet, creating convex regions in the resonance zone. An annular disk-shaped recurve section at the end of the sidewall structure forms magnetic mirrors keeping the plasma off the pole piece. A recurve section composed of magnetic material having a radial polarity forms convex regions and/or magnetic mirrors within the resonance zone.

  13. DISABILITY—IS IT PERMANENT?

    PubMed Central

    Thurber, Packard

    1957-01-01

    Too often cases of industrial injuries are submitted for permanent disability rating before maximum recovery is attained and the condition is permanent and stationary. This is frequently a situation that is detrimental to the injured working man, since his physical disability might be further reduced by additional treatment, and his future earning power and economic status thus be improved. Also it may be detrimental to the insurance carrier and/or employer, since in some instances it results in increased permanent disability award payments for portions of the condition which are not truly permanent. Inadequate medical reports also are a frequent cause of unfair awards. The necessary factors used to arrive at proper conclusions, the errors that have been observed and the importance of this problem are discussed. PMID:13446753

  14. Hybrid-secondary uncluttered permanent magnet machine and method

    DOEpatents

    Hsu, John S.

    2005-12-20

    An electric machine (40) has a stator (43), a permanent magnet rotor (38) with permanent magnets (39) and a magnetic coupling uncluttered rotor (46) for inducing a slip energy current in secondary coils (47). A dc flux can be produced in the uncluttered rotor when the secondary coils are fed with dc currents. The magnetic coupling uncluttered rotor (46) has magnetic brushes (A, B, C, D) which couple flux in through the rotor (46) to the secondary coils (47c, 47d) without inducing a current in the rotor (46) and without coupling a stator rotational energy component to the secondary coils (47c, 47d). The machine can be operated as a motor or a generator in multi-phase or single-phase embodiments and is applicable to the hybrid electric vehicle. A method of providing a slip energy controller is also disclosed.

  15. Design and Analysis of Tubular Permanent Magnet Linear Wave Generator

    PubMed Central

    Si, Jikai; Feng, Haichao; Su, Peng; Zhang, Lufeng

    2014-01-01

    Due to the lack of mature design program for the tubular permanent magnet linear wave generator (TPMLWG) and poor sinusoidal characteristics of the air gap flux density for the traditional surface-mounted TPMLWG, a design method and a new secondary structure of TPMLWG are proposed. An equivalent mathematical model of TPMLWG is established to adopt the transformation relationship between the linear velocity of permanent magnet rotary generator and the operating speed of TPMLWG, to determine the structure parameters of the TPMLWG. The new secondary structure of the TPMLWG contains surface-mounted permanent magnets and the interior permanent magnets, which form a series-parallel hybrid magnetic circuit, and their reasonable structure parameters are designed to get the optimum pole-arc coefficient. The electromagnetic field and temperature field of TPMLWG are analyzed using finite element method. It can be included that the sinusoidal characteristics of air gap flux density of the new secondary structure TPMLWG are improved, the cogging force as well as mechanical vibration is reduced in the process of operation, and the stable temperature rise of generator meets the design requirements when adopting the new secondary structure of the TPMLWG. PMID:25050388

  16. Design and analysis of tubular permanent magnet linear wave generator.

    PubMed

    Si, Jikai; Feng, Haichao; Su, Peng; Zhang, Lufeng

    2014-01-01

    Due to the lack of mature design program for the tubular permanent magnet linear wave generator (TPMLWG) and poor sinusoidal characteristics of the air gap flux density for the traditional surface-mounted TPMLWG, a design method and a new secondary structure of TPMLWG are proposed. An equivalent mathematical model of TPMLWG is established to adopt the transformation relationship between the linear velocity of permanent magnet rotary generator and the operating speed of TPMLWG, to determine the structure parameters of the TPMLWG. The new secondary structure of the TPMLWG contains surface-mounted permanent magnets and the interior permanent magnets, which form a series-parallel hybrid magnetic circuit, and their reasonable structure parameters are designed to get the optimum pole-arc coefficient. The electromagnetic field and temperature field of TPMLWG are analyzed using finite element method. It can be included that the sinusoidal characteristics of air gap flux density of the new secondary structure TPMLWG are improved, the cogging force as well as mechanical vibration is reduced in the process of operation, and the stable temperature rise of generator meets the design requirements when adopting the new secondary structure of the TPMLWG.

  17. High energy product permanent magnet having improved intrinsic coercivity and method of making same

    DOEpatents

    Ramesh, Ramamoorthy; Thomas, Gareth

    1990-01-01

    A high energy rare earth-ferromagnetic metal permanent magnet is disclosed which is characterized by improved intrinsic coercivity and is made by forming a particulate mixture of a permanent magnet alloy comprising one or more rare earth elements and one or more ferromagnetic metals and forming a second particulate mixture of a sintering alloy consisting essentially of 92-98 wt. % of one or more rare earth elements selected from the class consisting of Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures of two or more of such rare earth elements, and 2-8 wt. % of one or more alloying metals selected from the class consisting of Al, Nb, Zr, V, Ta, Mo, and mixtures of two or more of such metals. The permanent magnet alloy particles and sintering aid alloy are mixed together and magnetically oriented by immersing the mixture in an axially aligned magnetic field while cold pressing the mixture. The compressed mixture is then sintered at a temperature above the melting point of the sintering aid and below the melting point of the permanent magnet alloy to thereby coat the particle surfaces of the permanent magnetic alloy particles with the sintering aid while inhibiting migration of the rare earth element in the sintering aid into the permanent magnet alloy particles to thereby raise the intrinsic coercivity of the permanent magnet alloy without substantially lowering the high energy of the permanent magnet alloy.

  18. Axial Seamount - Under the hood of the volcano machine.

    NASA Astrophysics Data System (ADS)

    Arnulf, A. F.; Harding, A. J.; Kent, G. M.

    2015-12-01

    On the Juan de Fuca ridge, Axial volcano is the most volcanically active site of the northwestern Pacific and it has been continuously monitored through two complete eruption cycles, with an increased number of seafloor instruments, leading in 2014 to the deployment of a permanent, wired-to-shore, seafloor observatory. Accurate imaging of the internal structure of volcanic systems is critical in order to characterize and quantify mass and energy transport mechanisms in such dynamic environments. To produce high-resolution velocity/reflectivity structures of Axial volcano, here, we combined a synthetic ocean bottom experiment (SOBE), 3-D traveltime tomography, 2D elastic full waveform and a reverse time migration (RTM) formalism.We present an updated and more complete outlook of Axial volcano upper crustal structure. We find that the addition of 469,891 traveltime arrivals, from twelve different multichannel seismic lines, to a previous OBSs-based traveltime tomography inversion, greatly improved the resolution of the three-dimensional velocity structure. We observe two elongated crustal magma reservoir beneath the central volcano. We investigate the extent, volume and physical state of those magma reservoirs and provide images of the volcanic plumbing system. We use our 3D velocity structure to relocate several months of seismicity and track magma movements between the caldera and the eruption site. We show that crustal-aging is controlled by pipe-like pattern of focused hydrothermal circulation. We suggest that the subsiding caldera floor at Axial Volcano was initiated ~720kyr +/-100kyr and provides a near perfect trap for the ponding of lava flows.

  19. Golimumab for treatment of axial spondyloarthritis.

    PubMed

    Rios Rodriguez, Valeria; Poddubnyy, Denis

    2016-02-01

    Axial spondyloarthritis comprises two forms: nonradiographic (nonradiographic axial spondyloarthritis) and radiographic (better known as ankylosing spondylitis), which are often considered as two stages of one disease. Historically, all currently available TNF-α inhibitors were first investigated in ankylosing spondylitis and later on in nonradiographic axial spondyloarthritis. This year, EMA has granted golimumab approval for the treatment of active nonradiographic axial spondyloarthritis based on the recently published data from the GO-AHEAD study. This article summarizes recent data on efficacy and safety of golimumab in the treatment of ankylosing spondylitis and nonradiographic axial spondyloarthritis.

  20. Toroidal-Core Microinductors Biased by Permanent Magnets

    NASA Technical Reports Server (NTRS)

    Lieneweg, Udo; Blaes, Brent

    2003-01-01

    The designs of microscopic toroidal-core inductors in integrated circuits of DC-to-DC voltage converters would be modified, according to a proposal, by filling the gaps in the cores with permanent magnets that would apply bias fluxes (see figure). The magnitudes and polarities of the bias fluxes would be tailored to counteract the DC fluxes generated by the DC components of the currents in the inductor windings, such that it would be possible to either reduce the sizes of the cores or increase the AC components of the currents in the cores without incurring adverse effects. Reducing the sizes of the cores could save significant amounts of space on integrated circuits because relative to other integrated-circuit components, microinductors occupy large areas - of the order of a square millimeter each. An important consideration in the design of such an inductor is preventing magnetic saturation of the core at current levels up to the maximum anticipated operating current. The requirement to prevent saturation, as well as other requirements and constraints upon the design of the core are expressed by several equations based on the traditional magnetic-circuit approximation. The equations involve the core and gap dimensions and the magnetic-property parameters of the core and magnet materials. The equations show that, other things remaining equal, as the maximum current is increased, one must increase the size of the core to prevent the flux density from rising to the saturation level. By using a permanent bias flux to oppose the flux generated by the DC component of the current, one would reduce the net DC component of flux in the core, making it possible to reduce the core size needed to prevent the total flux density (sum of DC and AC components) from rising to the saturation level. Alternatively, one could take advantage of the reduction of the net DC component of flux by increasing the allowable AC component of flux and the corresponding AC component of current

  1. A low cost MRI permanent magnet prototype

    NASA Astrophysics Data System (ADS)

    Esparza-Coss, Emilio; Cole, David M.

    1998-08-01

    Here we present the proceedings in designing and constructing a low cost, friendly use, Magnetic Resonance Imaging (MRI) prototype magnet; 55 cm×45 cm×30 cm in size scaleable to full body; with a C-shaped assembly to provide open access to the 10 cm C-gap; operational at 0.22 Tesla where the low field increments the tissue contrast; structured with methodically selected and strategically positioned permanent magnets to reach the required field homogeneity as well as to be practically free of maintenance; and having iron flux return to leave an extremely low fringe field. The magnetic flux is funneled through the iron and focused by carefully designed and finely machined iron pole faces of 8.9 cm radius to create a homogeneity of less than 20 parts per million (PPM), without shimming, in a roughly 1.3 cm by 2 cm main axes oval region. An image of an okra plant was taken to test its performance.

  2. A low cost MRI permanent magnet prototype

    SciTech Connect

    Esparza-Coss, Emilio; Cole, David M.

    1998-08-28

    Here we present the proceedings in designing and constructing a low cost, friendly use, Magnetic Resonance Imaging (MRI) prototype magnet; 55 cmx45 cmx30 cm in size scaleable to full body; with a C-shaped assembly to provide open access to the 10 cm C-gap; operational at 0.22 Tesla where the low field increments the tissue contrast; structured with methodically selected and strategically positioned permanent magnets to reach the required field homogeneity as well as to be practically free of maintenance; and having iron flux return to leave an extremely low fringe field. The magnetic flux is funneled through the iron and focused by carefully designed and finely machined iron pole faces of 8.9 cm radius to create a homogeneity of less than 20 parts per million (PPM), without shimming, in a roughly 1.3 cm by 2 cm main axes oval region. An image of an okra plant was taken to test its performance.

  3. Qualitative permanence of Lotka-Volterra equations.

    PubMed

    Hofbauer, Josef; Kon, Ryusuke; Saito, Yasuhisa

    2008-12-01

    In this paper, we consider permanence of Lotka-Volterra equations. We investigate the sign structure of the interaction matrix that guarantees the permanence of a Lotka-Volterra equation whenever it has a positive equilibrium point. An interaction matrix with this property is said to be qualitatively permanent. Our results provide both necessary and sufficient conditions for qualitative permanence.

  4. Lodestone: Nature's own permanent magnet

    NASA Technical Reports Server (NTRS)

    Wasilewski, P.

    1976-01-01

    Magnetic hysteresis and microstructural details are presented which explain why the class of magnetic iron ores defined as proto-lodestones, can behave as permanent magnets, i.e. lodestones. Certain of these proto-lodestones which are not permanent magnets can be made into permanent magnets by charging in a field greater than 1000 oersted. This fact, other experimental observations, and field evidence from antiquity and the middle ages, which seems to indicate that lodestones are found as localized patches within massive ore bodies, suggests that lightning might be responsible for the charging of lodestones. The large remanent magnetization, high values of coercive force, and good time stability for the remanent magnetization are all characteristics of proto-lodestone iron ores which behave magnetically as fine scale ( 10 micrometer) intergrowths when subjected to magnetic hysteresis analysis. The magnetic results are easily understood by analysis of the complex proto lodestone microstructural patterns observable at the micrometer scale and less.

  5. [Improved design of permanent maglev impeller assist heart].

    PubMed

    Qian, Kunxi; Zeng, Pei; Ru, Weimin; Yuan, Haiyu

    2002-12-01

    Magnetic bearing has no mechanical contact between the rotor and stator. And a rotary pump with magnetic bearing has therefore no mechanical wear and thrombosis due to bearing. The available magnetic bearings, however, are devised with electric magnets, need complicated control and remarkable energy consumption. Resultantly, it is difficult to apply an electric magnetic bearing to rotary pump without disturbing its simplicity, implantability and reliability. The authors have developed a levitated impeller pump merely with permanent magnets. The rotor is supported by permanent magnetic forces radially. On one side of the rotor, the impeller is fixed; and on the other side of the rotor, the driven magnets are mounted. Opposite to this driven magnets, a driving motor coil with iron corn magnets is fastened to the motor axis. Thereafter, the motor drives the rotor via a rotating magnetic field. By laboratory tests with saline, if the rotor stands still or rotates under 4,000 rpm, the rotor has one-point contact axially with the driving motor coil. The contacting point is located in the center of the rotor. As the rotating speed increases gradually to more than 4,000 rpm, the rotor will detache from the stator axially. Then the rotor will be fully levitated. Since the axial levitation is produced by hydraulic force and the driven magnets have a gyro-effect, the rotor rotates very steadly during levitation. As a left ventricular assist device, the pump works in a rotating speed range of 5,000-8,000 rpm, the levitation of the impeller hence is ensured by practical use of the pump.

  6. [Improved design of permanent maglev impeller assist heart].

    PubMed

    Qian, Kunxi; Zeng, Pei; Ru, Weimin; Yuan, Haiyu

    2002-12-01

    Magnetic bearing has no mechanical contact between the rotor and stator. And a rotary pump with magnetic bearing has therefore no mechanical wear and thrombosis due to bearing. The available magnetic bearings, however, are devised with electric magnets, need complicated control and remarkable energy consumption. Resultantly, it is difficult to apply an electric magnetic bearing to rotary pump without disturbing its simplicity, implantability and reliability. The authors have developed a levitated impeller pump merely with permanent magnets. The rotor is supported by permanent magnetic forces radially. On one side of the rotor, the impeller is fixed; and on the other side of the rotor, the driven magnets are mounted. Opposite to this driven magnets, a driving motor coil with iron corn magnets is fastened to the motor axis. Thereafter, the motor drives the rotor via a rotating magnetic field. By laboratory tests with saline, if the rotor stands still or rotates under 4,000 rpm, the rotor has one-point contact axially with the driving motor coil. The contacting point is located in the center of the rotor. As the rotating speed increases gradually to more than 4,000 rpm, the rotor will detache from the stator axially. Then the rotor will be fully levitated. Since the axial levitation is produced by hydraulic force and the driven magnets have a gyro-effect, the rotor rotates very steadly during levitation. As a left ventricular assist device, the pump works in a rotating speed range of 5,000-8,000 rpm, the levitation of the impeller hence is ensured by practical use of the pump. PMID:12561356

  7. How Permanent Is Permanent Placement for Substance-Exposed Infants?

    ERIC Educational Resources Information Center

    Twomey, Jean E.; Lester, Barry M.

    2007-01-01

    The authors describe a study of families in the Family Drug Treatment Court (FTDC), an effort to promote permanent placement for substance-exposed infants within time requirements mandated by the 1997 Adoption and Safe Families Act (ASFA). The purpose of the study was to evaluate parent functioning after FTDC involvement, infant developmental…

  8. Semipermanent and permanent injectable fillers.

    PubMed

    Jones, Derek H

    2009-10-01

    Today, an impressive array of injectable dermal fillers for facial soft-tissue augmentation is available in the United States. These agents, most of which were introduced in the last half decade, represent a variety of semipermanent and permanent fillers across several categories. Physicians can choose between semipermanent fillers, such as hyaluronic acid derivatives (HA), calcium hydroxylapatite (CaHA), and poly-L-lactic acid (PLA), and longer-lasting, so-called "permanent fillers," such as polymethyl methacrylate microspheres (PMMA), highly purified forms of liquid silicone, and hydrogel polymers. PMID:19850193

  9. PWR AXIAL BURNUP PROFILE ANALYSIS

    SciTech Connect

    J.M. Acaglione

    2003-09-17

    The purpose of this activity is to develop a representative ''limiting'' axial burnup profile for pressurized water reactors (PWRs), which would encompass the isotopic axial variations caused by different assembly irradiation histories, and produce conservative isotopics with respect to criticality. The effect that the low burnup regions near the ends of spent fuel have on system reactivity is termed the ''end-effect''. This calculation will quantify the end-effects associated with Pressurized Water Reactor (PWR) fuel assemblies emplaced in a hypothetical 21 PWR waste package. The scope of this calculation covers an initial enrichment range of 3.0 through 5.0 wt% U-235 and a burnup range of 10 through 50 GWd/MTU. This activity supports the validation of the process for ensuring conservative generation of spent fuel isotopics with respect to criticality safety applications, and the use of burnup credit for commercial spent nuclear fuel. The intended use of these results will be in the development of PWR waste package loading curves, and applications involving burnup credit. Limitations of this evaluation are that the limiting profiles are only confirmed for use with the B&W 15 x 15 fuel assembly design. However, this assembly design is considered bounding of all other typical commercial PWR fuel assembly designs. This calculation is subject to the Quality Assurance Requirements and Description (QARD) because this activity supports investigations of items or barriers on the Q-list (YMP 2001).

  10. A direct torque control scheme for permanent magnet synchronous motors based on space vector modulation

    NASA Astrophysics Data System (ADS)

    Su, Xiao-hui; Xu, Shu-Ping

    2013-03-01

    In order to solve the problem of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) related to the flux and the torque ripple and the uncertainty of switching frequency, A novel direct torque control system based on space vector modulation(SVM-DTC) for permanent magnet synchronous motor was proposed. In this method flux and torque are controlled through stator voltage components in stator flux linkage coordinate axes and space vector modulation is used to control inverters. Therefore, the errors of torque and flux linkage could be compensated accurately. The whole system has only one easily adjustable PI adjuster and needs no high for hardware and easy for realize. The simulation results verify the feasibility of this method, reduction of the flux and the torque ripple, and the good performance of DTC.

  11. Experimental investigation on a colloidal damper rendered controllable under the variable magnetic field generated by moving permanent magnets

    NASA Astrophysics Data System (ADS)

    Suciu, B.

    2016-09-01

    In this work, a colloidal damper rendered controllable under variable magnetic fields is proposed and its controllability is experimentally evaluated. This absorber employs a water- based ferrofluid (FERROTEC MSGW10) in association with a liquid-repellent nanoporous solid matrix, consisted of particles of gamma alumina or/and silica gel. Control of the dynamic characteristics is obtained by moving permanent neodymium annular magnets, which are placed either on the piston head (axial magnetic field) or on the external surface of the cylinder (radial magnetic field). In order to properly select these magnets, flow visualizations inside of a transparent model damper were performed, and the quantity of the displaced liquid by the magnets through the damper's filter and through the nanoporous solid matrix was determined. Experimental data concerning variation of the magnetic flux density at the magnet surface versus the height of the magnet, and versus the target distance was collected. Based on such data, the suitable magnet geometry was decided. Then, the 3D structural model of the trial colloidal damper obtained by using Solidworks, and the excitation test rig are presented. From excitation tests on a ball-screw shaker, one confirmed larger damping abilities of the proposed absorber relative to the traditional colloidal damper, and also the possibility to adjust the damping coefficient according to the excitation type.

  12. Quark mass effect on axial charge dynamics

    NASA Astrophysics Data System (ADS)

    Guo, Er-dong; Lin, Shu

    2016-05-01

    We studied the effect of finite quark mass on the dynamics of the axial charge using the D3/D7 model in holography. The mass term in the axial anomaly equation affects both the fluctuation (generation) and dissipation of the axial charge. We studied the dependence of the effect on quark mass and an external magnetic field. For axial charge generation, we calculated the mass diffusion rate, which characterizes the helicity flipping rate. The rate is a nonmonotonous function of mass and can be significantly enhanced by the magnetic field. The diffusive behavior is also related to a divergent susceptibility of the axial charge. For axial charge dissipation, we found that in the long time limit, the mass term dissipates all the charge effectively generated by parallel electric and magnetic fields. The result is consistent with a relaxation time approximation. The rate of dissipation through mass term is a monotonous increasing function of both quark mass and a magnetic field.

  13. Dynamics of Permanent-Magnet Biased Active Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Fukata, Satoru; Yutani, Kazuyuki

    1996-01-01

    Active magnetic radial bearings are constructed with a combination of permanent magnets to provide bias forces and electromagnets to generate control forces for the reduction of cost and the operating energy consumption. Ring-shaped permanent magnets with axial magnetization are attached to a shaft and share their magnet stators with the electromagnets. The magnet cores are made of solid iron for simplicity. A simplified magnetic circuit of the combined magnet system is analyzed with linear circuit theory by approximating the characteristics of permanent magnets with a linear relation. A linearized dynamical model of the control force is presented with the first-order approximation of the effects of eddy currents. Frequency responses of the rotor motion to disturbance inputs and the motion for impulsive forces are tested in the non-rotating state. The frequency responses are compared with numerical results. The decay of rotor speed due to magnetic braking is examined. The experimental results and the presented linearized model are similar to those of the all-electromagnetic design.

  14. Frictionless Bearing Uses Permanent Magnets

    NASA Technical Reports Server (NTRS)

    1965-01-01

    The purpose of this innovation was to develop a frictionless bearing for high speed, light load applications. The device involves the incorporation of permanent magnets in the bearing design. The repulsion of like magnetic poles provides concentric support of the inner member so that no metallic contact occurs between the bearing surfaces.

  15. Magnetic Fields: Visible and Permanent.

    ERIC Educational Resources Information Center

    Winkeljohn, Dorothy R.; Earl, Robert D.

    1983-01-01

    Children will be able to see the concept of a magnetic field translated into a visible reality using the simple method outlined. Standard shelf paper, magnets, iron filings, and paint in a spray can are used to prepare a permanent and well-detailed picture of the magnetic field. (Author/JN)

  16. Microfilm Permanence and Archival Quality

    ERIC Educational Resources Information Center

    Avedon, Don M.

    1972-01-01

    The facts about microfilm permanence and archival quality are presented in simple terms. The major factors, including the film base material, the film emulsion, processing, and storage conditions are reviewed. The designations on the edge of the film are explained and a list of refernces provided. (14 references) (Author)

  17. Effect of the repulsive force in the HTSC-permanent magnet hybrid bearing system

    NASA Astrophysics Data System (ADS)

    Ohashi, S.; Kobayashi, S.

    2009-10-01

    Magnetic levitation using the pinning force of the YBaCuO high- Tc bulk superconductor (HTSC) materials has an advantage to achieve stable levitation without control. To increase levitation force, the HTSC-permanent magnet hybrid magnetic bearing system is introduced. A circular shaped three phase Nd-Fe-B permanent magnet is installed on the rotor, and HTSC bulk superconductor is set on the stator. The additional permanent magnet is installed under the HTSC. Repulsive force of the permanent magnet is used for levitation, and pinning force between the HTSC and permanent magnet is used for guidance force of the bearing. In this system, relationship between permanent magnet and the HTSC is important. When repulsive force of the permanent magnet is large, pinning force of superconductor is used to keep the rotor position. As a result, stability for the lateral direction is decreased with hybrid system. For levitation force, effect of the hybrid system is not observed with column HTSC. Compared with the ring HTSC results, the following thing is considered. Because there is no space that flux of one permanent magnet acts on the other one with the column HTSC configuration, interaction between two permanent magnets becomes small.

  18. Research on Magnetic Model of Low Resistance Permanent Magnet Pipe Belt Conveyor

    NASA Astrophysics Data System (ADS)

    Wang, Shuang; Li, De-yong; Guo, Yong-cun

    2016-09-01

    In view of the feasibility of a new type of low resistance permanent magnet pipe belt conveyor, the magnetic properties of the permanent magnet magnetic pipe conveyor belt system are studied. Based on the molecular current hypothesis, the mathematical model of the three dimensional radial magnetic force of permanent magnet pipe conveyor belt was established. The mathematical model of the radial magnetic force was derived, and the influence factors of the radial magnetic force were derived. The finite element simulation of permanent magnet-magnetic pipe conveyor belt magnetic model was carried out, then the magnetic flux density distribution chart under the conditions of different remanence intensity of different permanent magnet and different lengths of the permanent magnets (along the transport direction) were obtained. The simulation results are consistent with the calculation results, which shows that the permanent magnet pipe belt conveyor is feasible. Under certain conditions, the radial magnetic force has nonlinear increase relations with residual magnetism of permanent magnet and the length of the permanent magnet (along the transport direction).

  19. System Study for Axial Vane Engine Technology

    NASA Technical Reports Server (NTRS)

    Badley, Patrick R.; Smith, Michael R.; Gould, Cedric O.

    2008-01-01

    The purpose of this engine feasibility study was to determine the benefits that can be achieved by incorporating positive displacement axial vane compression and expansion stages into high bypass turbofan engines. These positive-displacement stages would replace some or all of the conventional compressor and turbine stages in the turbine engine, but not the fan. The study considered combustion occurring internal to an axial vane component (i.e., Diesel engine replacing the standard turbine engine combustor, burner, and turbine); and external continuous flow combustion with an axial vane compressor and an axial vane turbine replacing conventional compressor and turbine systems.

  20. Unsteady Flows in Axial Turbomachines

    NASA Technical Reports Server (NTRS)

    Marble, F. E.; Rannie, W. D.

    1957-01-01

    Of the various unsteady flows that occur in axial turbomachines certain asymmetric disturbances, of wave length large in comparison with blade spacing, have become understood to a certain extent. These disturbances divide themselves into two categories: self-induced oscillations and force disturbances. A special type of propagating stall appears as a self-induced disturbance; an asymmetric velocity profile introduced at the compressor inlet constitutes a forced disturbance. Both phenomena have been treated from a unified theoretical point of view in which the asymmetric disturbances are linearized and the blade characteristics are assumed quasi-steady. Experimental results are in essential agreement with this theory wherever the limitations of the theory are satisfied. For the self-induced disturbances and the more interesting examples of the forced disturbances, the dominant blade characteristic is the dependence of total pressure loss, rather than the turning angle, upon the local blade inlet angle.

  1. Axially grooved heat pipe study

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A technology evaluation study on axially grooved heat pipes is presented. The state-of-the-art is reviewed and present and future requirements are identified. Analytical models, the Groove Analysis Program (GAP) and a closed form solution, were developed to facilitate parametric performance evaluations. GAP provides a numerical solution of the differential equations which govern the hydrodynamic flow. The model accounts for liquid recession, liquid/vapor shear interaction, puddle flow as well as laminar and turbulent vapor flow conditions. The closed form solution was developed to reduce computation time and complexity in parametric evaluations. It is applicable to laminar and ideal charge conditions, liquid/vapor shear interaction, and an empirical liquid flow factor which accounts for groove geometry and liquid recession effects. The validity of the closed form solution is verified by comparison with GAP predictions and measured data.

  2. Axial cylinder internal combustion engine

    SciTech Connect

    Gonzalez, C.

    1992-03-10

    This patent describes improvement in a barrel type internal combustion engine including an engine block having axial-positioned cylinders with reciprocating pistons arranged in a circular pattern: a drive shaft concentrically positioned within the cylinder block having an offset portion extending outside the cylinder block; a wobble spider rotatably journaled to the offset portion; connecting rods for each cylinder connecting each piston to the wobble spider. The improvement comprising: a first sleeve bearing means supporting the drive shaft in the engine block in a cantilevered manner for radial loads; a second sleeve bearing means rotatably supporting the wobble spider on the offset portion of the drive shaft for radial loads; a first roller bearing means positioned between the offset portion of the drive shaft and the wobble spider carrying thrust loadings only; a second roller bearing means carrying thrust loads only reacting to the first roller bearing located on the opposite end of the driveshaft between the shaft and the engine block.

  3. Spoke permanent magnet machine with reduced torque ripple and method of manufacturing thereof

    DOEpatents

    Reddy, Patel Bhageerath; EL-Refaie, Ayman Mohamed Fawzi; Huh, Kum-Kang; Alexander, James Pellegrino

    2016-03-15

    An internal permanent magnet machine includes a rotor assembly having a shaft comprising a plurality of protrusions extending radially outward from a main shaft body and being formed circumferentially about the main shaft body and along an axial length of the main shaft body. A plurality of stacks of laminations are arranged circumferentially about the shaft to receive the plurality of protrusions therein, with each stack of laminations including a plurality of lamination groups arranged axially along a length of the shaft and with permanent magnets being disposed between the stacks of laminations. Each of the laminations includes a shaft protrusion cut formed therein to receive a respective shaft protrusion and, for each of the stacks of laminations, the shaft protrusion cuts formed in the laminations of a respective lamination group are angularly offset from the shaft protrusion cuts formed in the laminations in an adjacent lamination group.

  4. Diagnostics Systems for Permanent Hall Thrusters Development

    NASA Astrophysics Data System (ADS)

    Ferreira, Jose Leonardo; Soares Ferreira, Ivan; Santos, Jean; Miranda, Rodrigo; Possa, M. Gabriela

    This work describes the development of Permanent Magnet Hall Effect Plasma Thruster (PHALL) and its diagnostic systems at The Plasma Physics Laboratory of University of Brasilia. The project consists on the construction and characterization of plasma propulsion engines based on the Hall Effect. Electric thrusters have been employed in over 220 successful space missions. Two types stand out: the Hall-Effect Thruster (HET) and the Gridded Ion Engine (GIE). The first, which we deal with in this project, has the advantage of greater simplicity of operation, a smaller weight for the propulsion subsystem and a longer shelf life. It can operate in two configurations: magnetic layer and anode layer, the difference between the two lying in the positioning of the anode inside the plasma channel. A Hall-Effect Thruster-HET is a type of plasma thruster in which the propellant gas is ionized and accelerated by a magneto hydrodynamic effect combined with electrostatic ion acceleration. So the essential operating principle of the HET is that it uses a J x B force and an electrostatic potential to accelerate ions up to high speeds. In a HET, the attractive negative charge is provided by electrons at the open end of the Thruster instead of a grid, as in the case of the electrostatic ion thrusters. A strong radial magnetic field is used to hold the electrons in place, with the combination of the magnetic field and the electrostatic potential force generating a fast circulating electron current, the Hall current, around the axis of the Thruster, mainly composed by drifting electrons in an ion plasma background. Only a slow axial drift towards the anode occurs. The main attractive features of the Hall-Effect Thruster are its simple design and operating principles. Most of the Hall-Effect Thrusters use electromagnet coils to produce the main magnetic field responsible for plasma generation and acceleration. In this paper we present a different new concept, a Permanent Magnet Hall

  5. Tip clearance flow interaction with circumferential groove casing treatment in a transonic axial compressor

    NASA Astrophysics Data System (ADS)

    Ross, Mark Hamilton

    Experimental and computational studies were conducted to study the role of the tip leakage flow in axial compressor stall and the relationship between the tip clearance flow flow field and surge margin extension from circumferential groove casing treatment. The CFD results were used to identify the existence of an interface between the approach ow and the tip-leakage flow. The experiments used a surface streaking visualization method to identify the time-averaged location of this interface as a line of zero axial shear stress at the casing. The axial position of this line, denoted xzs, moved upstream with decreasing ow coefficient in both the experiments and computations. The line was consistently located at the rotor leading edge plane at the stalling flow coefficient, regardless of in flow boundary condition. These results were successfully modeled using a control volume approach that balanced the reverse axial momentum ux of the tip-leakage flow with the momentum flux of the approach fluid. Non-uniform tip clearance measurements demonstrated that movement of the interface upstream of the rotor leading edge plane leads to the generation of short length scale rotating disturbances. Therefore, stall was interpreted as a critical point in the momentum flux balance of the approach ow and the reverse axial momentum flux of the tip-leakage flow. Experimental measurements of surge margin extension from seven CGCT configurations with a fixed groove geometry demonstrated that the contribution of individual grooves in a multi-groove casing to surge margin extension is an (a) additive and (b) linear function of the smooth wall tip clearance axial momentum ux at the location of a each groove. Extending the axial momentum model to include the in uence of a CGCT showed that circumferential grooves reduce the tip leakage flow axial momentum through radial transport. The equivalent force due to a circumferential groove was demonstrated to be related to the smooth wall tip

  6. Levitation in the field of a nonsuperconducting coil with magnetic flux stabilization

    NASA Astrophysics Data System (ADS)

    Koshurnikov, E. K.

    2013-09-01

    A method providing the "frozen flux" conditions in a nonsuperconducting coil is suggested and demonstrated with a model. The feasibility of permanent magnet stable levitation in the field of the coil with magnetic flux stabilization and mean current control is shown. The method allows researchers to exploit permanent magnet-superconducting body interaction in physical devices, for example, to reproduce, using nonsuperconducting coils, the frozen magnetic flux conditions required for the stable levitation of the magnet over a superconducting body.

  7. Four Centuries of the Geocentric Axial Dipole Hypothesis

    NASA Astrophysics Data System (ADS)

    Tauxe, L.; Kent, D. V.

    2004-12-01

    William Gilbert first articulated what has come to be known as the geocentric axial dipole hypothesis. The GAD hypothesis is the principle on which paleogeographic reconstructions rely to constrain paleolatitude. For decades there have been calls for permanent non-dipole contributions to the time averaged field. Recently, these have demanded large contributions of the axial octupole, which, if valid, would call into question the general utility of the GAD hypothesis. In the process of geological recording of the geomagnetic field, ``Earth filters'' distort the directions. Many processes, for example, sedimentary inclination error and random tilting lead to a net shallowing of the observed direction. Therefore inclinations that are shallower than expected from GAD can be explained by recording biases, northward transport, or non-dipole geomagnetic fields. Using paleomagnetic data from the last five million years from well constrained lava flow data allows the construction of a statistical geomagnetic field model. Such a model can predict not only the average expected direction for a given latitude, but also the shape of the distribution of directions produced by secular variation. This allows us to differentiate among the possible explanations for shallow bias. We find no compelling reason to abandon the geocentric dipole hypothesis that has served us well for four centuries.

  8. The Effect of Axial Stress on YBCO Coils

    SciTech Connect

    Sampson, W.; Anerella, M.; Cozzolino, J.P.; Gupta, R.C.; Shiroyanagi, Y.; Evangelou, E.

    2011-03-28

    The large aspect ratio of typical YBCO conductors makes them ideal for constructing solenoids from pancake style coils. An advantage of this method is that each subunit can be tested before assembly into the finished magnet. The fact that conductors are available in relatively short lengths is another reason for using such a fabrication technique. The principal drawback is the large number of joints required to connect the coils together. When very high field solenoids such as those contemplated for the muon collider are built in this way the magnetic forces between pancakes can be very large. Extensive measurements have been made on the effect of stress on short lengths of conductor, but there is little or no data on the effect of intercoil loading. The experiment described in this paper was designed to test the ability of YBCO coils to withstand these forces. A spiral wound 'pancake' coil made from YBCO coated conductor has been stressed to a pressure of 100MPa in the axial direction at 77K. In this case axial refers to the coil so that the force is applied to the edge of the conductor. The effect on the critical current was small and completely reversible. Repeatedly cycling the pressure had no measureable permanent effect on the coil. The small current change observed exhibited a slight hysteretic behaviour during the loading cycle.

  9. A model of axial heterostructure formation in III-V semiconductor nanowires

    NASA Astrophysics Data System (ADS)

    Dubrovskii, V. G.

    2016-03-01

    A kinetic model of the formation of axial heterostructures in nanocrystalline wires (nanowires, NWs) of III-V semiconductor compounds growing according to the vapor-liquid-solid (VLS) mechanism is proposed. A general system of nonstationary equations for effective fluxes of two elements of the same group (e.g., group III) is formulated that allows the composition profile of a heterostructure to be calculated as a function of the coordinate and epitaxial growth conditions, including the flux of a group V element. Characteristic times of the composition relaxation, which determine the sharpness of the heteroboundary (heterointerface), are determined in the linear approximation. A temporal interruption (arrest) of fluxes during the switching of elements for a period exceeding these relaxation times must increase sharpness of the heteroboundary. Model calculations of the composition profile in a double GaAs/InAs/GaAs axial heterostructure have been performed for various NW radii.

  10. Study on the Levitation and Restoring Force Characteristics of the Improved HTS-permanent Magnet Hybrid Magnetic Bearing

    NASA Astrophysics Data System (ADS)

    Sugiyama, R.; Oguni, K.; Ohashi, S.

    We have developed the hybrid magnetic bearing using permanent magnets and high temperature bulk super conductor (HTS). In this system, the permanent magnet has ring type structure so that the permanent magnet and the HTS can be set to the stator. The pinning force of the HTS is used for the levitation and the guidance. Repulsive force of the permanent magnets was used in the conventional hybrid system. However the restoring force in the guidance direction of the conventional hybrid system decreases by the side slip force of the permanent magnets. In this research, attractive force of permanent magnets is used for increasing the load weight in the guidance direction. In this paper, influence of the hybrid system on the static characteristics of the rotor is studied. Three-dimensional numerical analysis of the linkage flux (in the levitation and the guidance direction) in the HTS is undertaken. The stator side permanent magnet increases the linkage flux of the levitation direction. Therefore in the hybrid system the linkage flux of the levitation direction increases. The levitation and restoring force of the rotor is measured. The levitation force of the hybrid system becomes smaller than that of the non-hybrid one by attractive force. The rotor in the hybrid system is supported by the pinning force and attractive force. The restoring force of the hybrid system becomes larger than that of the non-hybrid one because of increasing the linkage flux of the levitation direction.

  11. Development of a miniature permanent magnetic circuit for nuclear magnetic resonance chip

    NASA Astrophysics Data System (ADS)

    Lu, Rongsheng; Yi, Hong; Wu, Weiping; Ni, Zhonghua

    2013-07-01

    The existing researches of miniature magnetic circuits focus on the single-sided permanent magnetic circuits and the Halbach permanent magnetic circuits. In the single-sided permanent magnetic circuits, the magnetic flux density is always very low in the work region. In the Halbach permanent magnetic circuits, there are always great difficulties in the manufacturing and assembly process. The static magnetic flux density required for nuclear magnetic resonance(NMR) chip is analyzed based on the signal noise ratio(SNR) calculation model, and then a miniature C-shaped permanent magnetic circuit is designed as the required magnetic flux density. Based on Kirchhoff's law and magnetic flux refraction principle, the concept of a single shimming ring is proposed to improve the performance of the designed magnetic circuit. Using the finite element method, a comparative calculation is conducted. The calculation results demonstrate that the magnetic circuit improved with a single shimming has higher magnetic flux density and better magnetic field homogeneity than the one improved with no shimming ring or double shimming rings. The proposed magnetic circuit is manufactured and its experimental test platform is also built. The magnetic flux density measured in the work region is 0.7 T, which is well coincided with the theoretical design. The spatial variation of the magnetic field is within the range of the instrument error. At last, the temperature dependence of the magnetic flux density produced by the proposed magnetic circuit is investigated through both theoretical analysis and experimental study, and a linear functional model is obtained. The proposed research is crucial for solving the problem in the application of NMR-chip under different environmental temperatures.

  12. Liquid rocket engine axial-flow turbopumps

    NASA Technical Reports Server (NTRS)

    Scheer, D. D.; Huppert, M. C.; Viteri, F.; Farquhar, J.; Keller, R. B., Jr. (Editor)

    1978-01-01

    The axial pump is considered in terms of the total turbopump assembly. Stage hydrodynamic design, pump rotor assembly, pump materials for liquid hydrogen applications, and safety factors as utilized in state of the art pumps are among the topics discussed. Axial pump applications are included.

  13. Thermal Activation in Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Bance, S.; Fischbacher, J.; Kovacs, A.; Oezelt, H.; Reichel, F.; Schrefl, T.

    2015-06-01

    The coercive field of permanent magnets decays with temperature. At non-zero temperatures, the system can overcome a finite energy barrier through thermal fluctuations. Using finite element micromagnetic simulations, we quantify this effect, which reduces coercivity in addition to the decrease of the coercive field associated with the temperature dependence of the anisotropy field, and validate the method through comparison with existing experimental data.

  14. Cytokine profiles in axial spondyloarthritis

    PubMed Central

    Madej, Marta; Nowak, Beata; Sokolik, Renata; Chlebicki, Arkadiusz; Korman, Lucyna; Woytala, Patryk; Lubiński, Łukasz; Wiland, Piotr

    2015-01-01

    Objectives Current studies concentrate on the cytokine network and its role in the pathogenesis of spondyloarthritis (SpA). In this study, we analyzed whether the serum cytokine profile (interleukins: IL-10, IL-11, IL-12, IL-15, IL-17, IL-23 and IL-33) correlates with demographic data, clinical manifestations, disease activity and treatment outcome in a group of patients with axial spondyloarthritis. Material and methods Forty-nine patients with an established diagnosis of axial spondyloarthritis (aSpA) and 19 healthy volunteers as controls were enrolled in the study. Clinical evaluation included patient's medical history, 44 joint count, back pain intensity and global disease activity in the preceding week (VAS), the duration of morning stiffness and blood tests. Disease activity was assessed using BASDAI and ASDAS-CRP. Serum concentration of IL-10, IL-11, IL-12, IL-15, IL-17, IL-23 and IL-33 was determined. Results In patients with aSpA, elevated serum concentration of IL-10, IL-15, IL-17 and IL-23 was detected. In the aSpA group we detected higher values of serum concentration of IL-23 and IL-33 in the subgroup with anterior uveitis (83.1 ±184.0 pg/ml vs. 14.0 ±17.1 pg/ml, p < 0.0001 and 45.5 ±71.9 pg/ml vs. 18.4 ±14.3 pg/ml, p < 0.0001, respectively). Additionally, in the subgroup with peripheral arthritis, elevation of serum concentration of IL-12 (249.3 ±246.9 pg/ml vs. 99.9 ±105.9 pg/ml, p = 0.0001) was detected. Patients with preradiological SpA had higher serum concentration of IL-17 than patients with established diagnosis of AS (6.37 ±8.50 pg/ml vs. 2.04 ±2.98 pg/ml, p = 0.0295). No differences in serum concentration of analyzed cytokines were found between the subgroup with low to moderate disease activity and the subgroup with high to very high disease activity. Conclusions We report that in aSpA patients, compared to controls, elevated serum concentrations of IL-10, IL-15, IL-17 and IL-23 were observed. Some cytokines may predispose to a more

  15. Axial interaction free-electron laser

    DOEpatents

    Carlsten, B.E.

    1997-09-02

    Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies. 5 figs.

  16. Axial interaction free-electron laser

    DOEpatents

    Carlsten, Bruce E.

    1997-01-01

    Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies.

  17. Axial polarizers based on dichroic liquid crystals

    NASA Astrophysics Data System (ADS)

    Nersisyan, Sarik; Tabiryan, Nelson; Steeves, Diane M.; Kimball, Brian R.

    2010-08-01

    Polarizers capable of producing linearly polarized beams with axial (radial and azimuthal) symmetry have been fabricated with the aid of a dichroic liquid crystal. Photoalignment was achieved using a printing technique to reduce the UV exposure time required for production of axially aligning substrates from 1 h, typical for direct writing techniques, to 10 min. The polarizing features of axial polarizers and their pairs are characterized and their differences outlined. We demonstrate that the transmission switching contrast of an axial polarizer/analyzer pair, comprised of an electrically controlled liquid crystal cell, is comparable to conventional systems with linear polarizers. The opportunities for using axial polarizers for polarization imaging, sensor protection, and nonlinear optics are discussed. Particularly, we show that the technology could reduce the fluence of a laser beam on an optical sensor without affecting imaging.

  18. Magnetostatic simulation on a novel design of axially multi-coiled magnetorheological brakes

    NASA Astrophysics Data System (ADS)

    Ubaidillah, Permata, A. N. S.; Wibowo, A.; Budiana, E. P.; Yahya, I.; Mazlan, S. A.

    2016-03-01

    This paper describes the 3D magnetostatic simulation of a novel design axially multi-coiled magnetorheological (MRB). The proposed model is expected to produce a concentrated magnetic flux on the surface of the rotor disk brake. Thus, the braking torque enhancement is expected to be higher than that of conventional big size single-coil-equipped disk-type MRB. The axially multi-coiled MRB design features multiple electromagnetic poles from by several coils placed in the axial direction outside the MRB body. The magnetostatic analysis was developed utilizing finite element software namely ANSOFT-MAXWELL in 3D environment. The distribution of magnetic flux was investigated in a pair of the coil that represents the other pairs of electromagnetic parts. The simulation was done in 0.5 mm gap filled by magnetorheological fluids (MRFs) (MRF-132DG). The simulation was performed in various applied currents i.e. 0.25, 0.5, 0.75, 1, 1.5, and 2 Amperes. The results showed that the axially multi-coiled MRB provides a considerable magnetic flux (maximum of 337 mT/area). The active energizing areas of the MRB are proven to be more intensive than the conventional MRB. The proposed MRB exhibited a compact and robust design for achieving high torque MRB.

  19. Large needle suction aspiration of permanent fillers.

    PubMed

    Wilson, Yushan L; Ellis, David A F

    2011-10-01

    Temporary injectable fillers have become so widely accepted within the cosmetic medical industry that permanent fillers with longer lasting effects are fast gaining popularity. Both patients and physicians alike have eagerly sought a product to minimize the inconvenience and cost of repeated injections. However, the fear is that the use of permanent fillers may lead to permanent problems. We describe here an in-office technique to remove permanent injectable fillers that achieves consistent, natural results with minimal risk of scarring.

  20. Non-axial muscle stress and stiffness.

    PubMed

    Zahalak, G I

    1996-09-01

    A generalization is developed of the classic two-state Huxley cross-bridge model to account for non-axial active stress and stiffness. The main ingredients of the model are: (i) a relation between the general three-dimensional deformation of an element of muscle and the deformations of the cross-bridges, that assumes macroscopic deformation is transmitted to the myofibrils, (ii) radial as well as axial cross-bridge stiffness, and (iii) variations of the attachment and detachment rates with lateral filament spacing. The theory leads to a generalized Huxley rate equation on the bond-distribution function, n(zeta, theta, t), of the form [equation: see text] where the Dij are the components of the relative velocity gradient and rho and ñ are functions of the polar angle, theta, and time that describe, respectively, the deformation of the myofilament lattice and the distribution of accessible actin sites (both of these functions can be calculated from the macroscopic deformation). Explicit expressions, in terms of n, are derived for the nine components of the active stress tensor, and the 21 non-vanishing components of the active stiffness tensor; the active stress tensor is found to be unsymmetric. The theory predicts that in general non-axial deformations will modify active axial stress and stiffness, and also give rise to non-axial (e.g., shearing) components. Under most circumstances the magnitudes of the non-axial stress and stiffness components will be small compared with the axial and, further, the effects of non-axial deformation rates will be small compared with those of the axial rate. Large transverse deformations may, however, greatly reduce the axial force and stiffness. The theory suggests a significant mechanical role for the non-contractile proteins in muscle, namely that of equilibrating the unsymmetric active stresses. Some simple applications of the theory are provided to illustrate its physical content. PMID:8917737

  1. Combustion enhancement by axial vortices

    NASA Astrophysics Data System (ADS)

    Gutmark, E.; Schadow, K. C.; Parr, T. P.; Parr, D. M.; Wilson, K. J.

    1987-06-01

    A tapered slot jet was studied experimentally in nonreacting and reacting tests using hot-wire anemometry, water-tunnel flow visualization, and Planar Laser Induced Fluorescence (PLIF). The tapered slot jet is a modified elliptic jet which has a conical contraction leading to its outlet. The added contraction changes the entire flow field. The jet spread in the major axis plane is larger than in the minor axis plane, which is the opposite behavior of an elliptic jet. Consequently, no axes switching, typical to an elliptic jet, is observed. The turbulence amplification in the jet core is higher than in circular and elliptic jets. The different behavior is attributed to the change in flow direction, inside the nozzle, from the conical section to the slot outlet. During this transition, the flow acquires angular momentum thereby generating axial vorticity. The influence of the contraction angle and the outlet aspect ratio were investigated. The effect of the augmented turbulence on reactive flow was tested in a premixed flame. The combustion rate was augmented in both the core and edges of the flame relative to a circular burner.

  2. 21 CFR 886.4445 - Permanent magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove...

  3. 21 CFR 886.4445 - Permanent magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove...

  4. 21 CFR 886.4445 - Permanent magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove...

  5. 22 CFR 401.3 - Permanent offices.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Permanent offices. 401.3 Section 401.3 Foreign Relations INTERNATIONAL JOINT COMMISSION, UNITED STATES AND CANADA RULES OF PROCEDURE General § 401.3 Permanent offices. The permanent offices of the Commission shall be at Washington, in the District...

  6. Teaching Object Permanence: An Action Research Study

    ERIC Educational Resources Information Center

    Bruce, Susan M.; Vargas, Claudia

    2013-01-01

    "Object permanence," also known as "object concept" in the field of visual impairment, is one of the most important early developmental milestones. The achievement of object permanence is associated with the onset of representational thought and language. Object permanence is important to orientation, including the recognition of landmarks.…

  7. Axial expansion methods for solution of the multi-dimensional neutron diffusion equation

    SciTech Connect

    Beaklini Filho, J.F.

    1984-01-01

    The feasibility and practical implementation of axial expansion methods for the solution of the multi-dimensional multigroup neutron diffusion (MGD) equations is investigated. The theoretical examination which is applicable to the general MGD equations in arbitrary geometry includes the derivation of a new weak (reduced) form of the MGD equations by expanding the axial component of the neutron flux in a series of known trial functions and utilizing the Galerkin weighting. A general two-group albedo boundary condition is included in the weak form as a natural boundary condition. The application of different types of trial functions is presented.

  8. Experimental evidence of the superfocusing effect for axially channeled MeV protons

    NASA Astrophysics Data System (ADS)

    Motapothula, M.; Petrović, S.; Nešković, N.; Breese, M. B. H.

    2016-08-01

    Sub-Ångström focusing of megaelectronvolt (MeV) ions within axial channels was predicted over 10 years ago, but evidence proved elusive. We present experimental angular distributions of axially channeled MeV protons in a 55-nm-thick (001) silicon membrane through which multiple scattering is negligible. Fine angular structure is in excellent agreement with Monte Carlo simulations based on three interaction potentials, providing indirect evidence of the existence of the superfocusing effect with flux enhancement of around 800 within a focused beam width of ˜20 pm .

  9. A compact permanent magnet cyclotrino for accelerator mass spectrometry

    SciTech Connect

    Young, A.T.; Clark, D.J.; Kunkel, W.B.; Leung, K.N.; Li, C.Y.

    1995-02-01

    The authors describe the development of a new instrument for the detection of trace amounts of rare isotopes, a Cyclotron Mass Spectrometer (CMS). A compact low energy cyclotron optimized for high mass resolution has been designed and has been fabricated. The instrument has high sensitivity and is designed to measure carbon-14 at abundances of < 10{sup {minus}12}. A novel feature of the instrument is the use of permanent magnets to energize the iron poles of the cyclotron. The instrument uses axial injection, employing a spiral inflector. The instrument has been assembled and preliminary measurements of the magnetic field show that it has a uniformity on the order of 2 parts in 10{sup 4}.

  10. Flow Split Venturi, Axially-Rotated Valve

    DOEpatents

    Walrath, David E.; Lindberg, William R.; Burgess, Robert K.; LaBelle, James

    2000-02-22

    The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop (characterized by a lower loss coefficient) by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. Similarly, the valve is designed, in some embodiments, to produce streamlined flow within the valve. An axially aligned outlet may also increase the flow efficiency. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal wide radius elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane. A seal separator may increase the useful life of the seal between the fixed and rotatable portions.

  11. Permanent-File-Validation Utility Computer Program

    NASA Technical Reports Server (NTRS)

    Derry, Stephen D.

    1988-01-01

    Errors in files detected and corrected during operation. Permanent File Validation (PFVAL) utility computer program provides CDC CYBER NOS sites with mechanism to verify integrity of permanent file base. Locates and identifies permanent file errors in Mass Storage Table (MST) and Track Reservation Table (TRT), in permanent file catalog entries (PFC's) in permit sectors, and in disk sector linkage. All detected errors written to listing file and system and job day files. Program operates by reading system tables , catalog track, permit sectors, and disk linkage bytes to vaidate expected and actual file linkages. Used extensively to identify and locate errors in permanent files and enable online correction, reducing computer-system downtime.

  12. A clip-on Zeeman slower using toroidal permanent magnets.

    PubMed

    Krzyzewski, S P; Akin, T G; Dahal, Parshuram; Abraham, E R I

    2014-10-01

    We present the design of a zero-crossing Zeeman slower for (85)Rb using rings of flexible permanent magnets. The design is inexpensive, requires no power or cooling, and can be easily attached and removed for vacuum maintenance. We show theoretically that such a design can reproduce a magnetic field profile of a standard zero-crossing Zeeman slower. Experimental measurements of a prototype and comparisons to theoretical simulations demonstrate the feasibility of the design and point toward future improvements. Simulations show an atom flux similar to other Zeeman slowers.

  13. A clip-on Zeeman slower using toroidal permanent magnets

    SciTech Connect

    Krzyzewski, S. P.; Akin, T. G.; Dahal, Parshuram; Abraham, E. R. I.

    2014-10-15

    We present the design of a zero-crossing Zeeman slower for {sup 85}Rb using rings of flexible permanent magnets. The design is inexpensive, requires no power or cooling, and can be easily attached and removed for vacuum maintenance. We show theoretically that such a design can reproduce a magnetic field profile of a standard zero-crossing Zeeman slower. Experimental measurements of a prototype and comparisons to theoretical simulations demonstrate the feasibility of the design and point toward future improvements. Simulations show an atom flux similar to other Zeeman slowers.

  14. Quasi permanent superconducting magnet of very high field

    NASA Technical Reports Server (NTRS)

    Ren, Y.; Liu, J.; Weinstein, R.; Chen, I. G.; Parks, D.; Xu, J.; Obot, V.; Foster, C.

    1993-01-01

    We report on persistent field in a quasi-permanent magnet made of high temperature superconductor. The material has an average of 40 percent molar excess of Y, relative to Y1Ba2Cu3O7 and has been irradiated with high energy light ions at 200 MeV. The magnet, which traps 1.52 T at 77.3 K, traps nearly 4 T at 64.5 K. No evidence of giant flux jump or sample cracking was observed.

  15. A clip-on Zeeman slower using toroidal permanent magnets.

    PubMed

    Krzyzewski, S P; Akin, T G; Dahal, Parshuram; Abraham, E R I

    2014-10-01

    We present the design of a zero-crossing Zeeman slower for (85)Rb using rings of flexible permanent magnets. The design is inexpensive, requires no power or cooling, and can be easily attached and removed for vacuum maintenance. We show theoretically that such a design can reproduce a magnetic field profile of a standard zero-crossing Zeeman slower. Experimental measurements of a prototype and comparisons to theoretical simulations demonstrate the feasibility of the design and point toward future improvements. Simulations show an atom flux similar to other Zeeman slowers. PMID:25362368

  16. Permanent magnet undulator for SPEAR

    SciTech Connect

    Halbach, K.; Chin, J.; Hoyer, E.; Winick, H.; Cronin, R.; Yang, J.; Zambre, Y.

    1981-03-01

    A 30 period permanent magnet (SmCo/sub 5/) undulator has been designed, built and tested. The period is 6.1 cm, overall length is 1.95 m, and the gap is variable from 2.7 cm to 6.0 cm. Magnetic measurements at the midplane with a 2.7 cm gap show that the field is sinusoidal with a peak value of .28 T. Construction details and magnetic measurements are presented along with the spectral distribution of radiation produced by 3.0 GeV electrons traversing the undulator.

  17. Method of making permanent magnets

    DOEpatents

    McCallum, R. William; Dennis, Kevin W.; Lograsso, Barbara K.; Anderson, Iver E.

    1993-09-07

    A method for making an isotropic permanent magnet comprises atomizing a melt of a rare earth-transition metal alloy (e.g., an Nd--Fe--B alloy enriched in Nd and B) under conditions to produce protectively coated, rapidly solidified, generally spherical alloy particles wherein a majority of the particles are produced/size classified within a given size fraction (e.g., 5 to 40 microns diameter) exhibiting optimum as-atomized magnetic properties and subjecting the particles to concurrent elevated temperature and elevated isotropic pressure for a time effective to yield a densified, magnetically isotropic magnet compact having enhanced magnetic properties and mechanical properties.

  18. Method of making permanent magnets

    DOEpatents

    McCallum, R.W.; Dennis, K.W.; Lograsso, B.K.; Anderson, I.E.

    1993-09-07

    A method for making an isotropic permanent magnet comprises atomizing a melt of a rare earth-transition metal alloy (e.g., an Nd--Fe--B alloy enriched in Nd and B) under conditions to produce protectively coated, rapidly solidified, generally spherical alloy particles. Wherein a majority of the particles are produced/size classified within a given size fraction (e.g., 5 to 40 microns diameter) exhibiting optimum as-atomized magnetic properties and subjecting the particles to concurrent elevated temperature and elevated isotropic pressure for a time effective to yield a densified, magnetically isotropic magnet compact having enhanced magnetic properties and mechanical properties. 13 figures.

  19. Investigating the Dynamics of Canonical Flux Tubes

    NASA Astrophysics Data System (ADS)

    von der Linden, Jens; Carroll, Evan; Kamikawa, Yu; Lavine, Eric; Vereen, Keon; You, Setthivoine

    2013-10-01

    Canonical flux tubes are defined by tracing areas of constant magnetic and fluid vorticity flux. This poster will present the theory for canonical flux tubes and current progress in the construction of an experiment designed to observe their evolution. In the zero flow limit, canonical flux tubes are magnetic flux tubes, but in full form, present the distinct advantage of reconciling two-fluid plasma dynamics with familiar concepts of helicity, twists and linkages. The experiment and the DCON code will be used to investigate a new MHD stability criterion for sausage and kink modes in screw pinches that has been generalized to magnetic flux tubes with skin and core currents. Camera images and a 3D array of ˙ B probes will measure tube aspect-ratio and ratio of current-to-magnetic flux, respectively, to trace these flux tube parameters in a stability space. The experiment's triple electrode planar gun is designed to generate azimuthal and axial flows. These diagnostics together with a 3D vector tomographic reconstruction of ion Doppler spectroscopy will be used to verify the theory of canonical helicity transport. This work was sponsored in part by the US DOE Grant DE-SC0010340.

  20. Axial grading of inert matrix fuels

    SciTech Connect

    Recktenwald, G. D.; Deinert, M. R.

    2012-07-01

    Burning actinides in an inert matrix fuel to 750 MWd/kg IHM results in a significant reduction in transuranic isotopes. However, achieving this level of burnup in a standard light water reactor would require residence times that are twice that of uranium dioxide fuels. The reactivity of an inert matrix assembly at the end of life is less than 1/3 of its beginning of life reactivity leading to undesirable radial and axial power peaking in the reactor core. Here we show that axial grading of the inert matrix fuel rods can reduce peaking significantly. Monte Carlo simulations are used to model the assembly level power distributions in both ungraded and graded fuel rods. The results show that an axial grading of uranium dioxide and inert matrix fuels with erbium can reduces power peaking by more than 50% in the axial direction. The reduction in power peaking enables the core to operate at significantly higher power. (authors)

  1. A Compliant Casing for Transonic Axial Compressors

    NASA Technical Reports Server (NTRS)

    Bloch, Gregory S.; Hah, Chunill

    2003-01-01

    A viewgraph presentation on the concept of compliant casing for transonic axial compressors is shown. The topics include: 1) Concept for compliant casing; 2) Rig and facility details; 3) Experimental results; and 4) Numerical results.

  2. Temperature compensation of NdFeB permanent magnets

    SciTech Connect

    Kim, S.H.; Doose, C.

    1997-08-01

    Permanent magnet blocks of NdFeB have a relatively high maximum energy product. Because of its relatively low Curie temperature, however, NdFeB has a large temperature coefficient for its residual induction. The temperature coefficients of the relative magnetic fields ({Delta}B/B)/{Delta}T in the air gap of NdFeB dipole magnets were reduced from {minus}1.1 {times} 10{sup {minus}3}/c to less than 2 {times} 10{sup {minus}5}/{degree}C under operating temperatures of {+-} 6 C. This was achieved passively by using 1.25-mm-thick strips of 30%-Ni-Fe alloy as flux shunts for the NdFeB blocks. The magnets with soft-steel poles and flux-return yokes were assembled and measured in a temperature-controlled environment.

  3. Planned Axial Reorientation Investigation on Sloshsat

    NASA Technical Reports Server (NTRS)

    Chato, David J.

    2000-01-01

    This paper details the design and logic of an experimental investigation to study axial reorientation in low gravity. The Sloshsat free-flyer is described. The planned axial reorientation experiments and test matrixes are presented. Existing analytical tools are discussed. Estimates for settling range from 64 to 1127 seconds. The planned experiments are modelled using computational fluid dynamics. These models show promise in reducing settling estimates and demonstrate the ability of pulsed high thrust settling to emulate lower thrust continuous firing.

  4. High temperature co-axial winding transformers

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.; Novotny, Donald W.

    1993-01-01

    The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

  5. Confronting electron and neutrino-nucleus interactions: Can the axial mass anomaly be resolved?

    NASA Astrophysics Data System (ADS)

    Benhar, Omar

    2014-04-01

    Comparison between electron- and neutrino-nucleus scattering data suggests that the so-called axial mass anomaly — i.e., the large disagreement between the value of the nucleon axial mass extracted from the analysis of neutrino interactions with carbon and oxygen and that obtained from deuteron data — is a manifestation of the difficulties in the interpretation of the flux averaged neutrino cross-sections. In this short review, I discuss the role of reaction mechanisms leading to the excitation of two particle-two hole final states of the target nucleus, which are believed to be responsible for the observed excess of quasielastic events, and argue that taking into account their effect may help to reconcile the sizeably different values of the axial mass reported by the MiniBooNe and NOMAD Collaborations.

  6. Zonal spherical aberration correction utilizing axial electrodes

    NASA Astrophysics Data System (ADS)

    Chao, Liang C.

    2005-01-01

    Spherical aberration is important in focused ion beam applications where large aperture angles are needed to obtain high beam currents because it results in large tails on the current density distribution. Merwe has shown that for coaxial lenses, negative spherical aberration can be found for rays pass through zonal regions. Merwe"s calculation is valid only for periodic or quasi-periodic lenses and requires a constant axial potential distribution. We have calculated zonal focusing properties of lenses with axial electrodes using nine-point finite difference method and direct ray tracing. Our calculation results indicate that an axial electrode protruding partially into the lens can correct the spherical aberration. When a three-element electrostatic lens is operated at deceleration mode, the introduction of an axial electrode creates zonal regions where the spherical aberration is negative. At deceleration mode, the induced surface charges on the axial electrode have an opposite sign relative to the primary beam. This is in agreement with our previous findings on the study of the correction of spherical aberration utilizing space charges. Same phenomenon was found when an axial electrode is used in conjunction with a cathode lens.

  7. Split Venturi, Axially-Rotated Valve

    DOEpatents

    Walrath, David E.; Lindberg, William R.; Burgess, Robert K.

    2000-08-29

    The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop (characterized by a lower loss coefficient) by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. Similarly, the valve is designed, in some embodiments, to produce streamlined flow within the valve. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal wide radius elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane.

  8. Prospects for Non-Rare Earth Permanent Magnets for Traction Motors and Generators

    NASA Astrophysics Data System (ADS)

    Kramer, M. J.; McCallum, R. W.; Anderson, I. A.; Constantinides, S.

    2012-07-01

    With the advent of high-flux density permanent magnets based on rare earth elements such as neodymium (Nd) in the 1980s, permanent magnet-based electric machines had a clear performance and cost advantage over induction machines when weight and size were factors such as in hybrid electric vehicles and wind turbines. However, the advantages of the permanent magnet-based electric machines may be overshadowed by supply constraints and high prices of their key constituents, rare earth elements, which have seen nearly a 10-fold increase in price in the last 5 years and the imposition of export limits by the major producing country, China, since 2010. We outline the challenges, prospects, and pitfalls for several potential alloys that could replace Nd-based permanent magnets with more abundant and less strategically important elements.

  9. Prospects for Non-Rare Earth Permanent Magnets for Traction Motors and Generators

    SciTech Connect

    Kramer, Matthew; McCallum, Kendall; Anderson, Iver; Constantinides, Steven

    2012-06-29

    With the advent of high-flux density permanent magnets based on rare earth elements such as neodymium (Nd) in the 1980s, permanent magnet-based electric machines had a clear performance and cost advantage over induction machines when weight and size were factors such as in hybrid electric vehicles and wind turbines. However, the advantages of the permanent magnet-based electric machines may be overshadowed by supply constraints and high prices of their key constituents, rare earth elements, which have seen nearly a 10-fold increase in price in the last 5 years and the imposition of export limits by the major producing country, China, since 2010. We outline the challenges, prospects, and pitfalls for several potential alloys that could replace Nd-based permanent magnets with more abundant and less strategically important elements.

  10. Determining if an axially rotated solenoid will induce a radial EMF

    NASA Astrophysics Data System (ADS)

    MacDermott, Dustin R.

    The nature of the electromagnetic field of an axially rotated solenoid or magnet is investigated. The investigations reviewed suggest the possibility of a radially emitted electric field by either: axially rotated magnetic field lines, or a relativistic change in charge of the electron. For a very long solenoid a relativistic change in charge leaves no electric field inside while leaving an electric field outside. The concept of axially rotating magnetic field lines gives an opposite prediction. They both seem to be in contradiction to the standard model of induction, which gives no change in the electric field for a rotated solenoid or magnet. An experiment by Joseph B. Tate [48], [49] conducted in 1968 seemed to have measured a change in charge outside of a rotated solenoid. Another experiment by Barnett [3] in 1912 reported measuring no electric field inside of a rotated solenoid. Further experimentation was decided necessary and the method decided upon to attempt detection of the radial E or EMF induced by an axially rotating B field or change in charge is two concentric capacitor plates, one inside and the other outside an axially rotated solenoid. The solenoid was rotated on a lathe for the test. A concentric capacitor around an axially rotated permanent neodymium magnet was also used as a test. These experiments proved very challenging because of the small magnitude of the predicted effect. Nevertheless, the bulk of the evidence obtained indicates that no induced E arises when a magnetic source is rotated about its magnetic axis, thus supporting the standard field model of electromagnetic induction, and casting doubt on the alternative theories of magnetic field line rotation or relativistic charge enhancement.

  11. Production of low axial energy spread ion beams with multicusp sources

    SciTech Connect

    Lee, Y.H.Y.

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.

  12. Methane flux time series for tundra environments

    SciTech Connect

    Whalen, S.C.; Reeburgh, W.E. )

    1988-12-01

    Seasonal measurements of net methane flux were made at permanent sites representing important components of arctic tundra. The sites include Eriophorum tussocks, intertussock depressions, moss-covered areas, and Carex stands. Methane fluxes showed high diel, seasonal, intra site, and between site variability. Eriophorum tussocks and Carex dominated methane release to the atmosphere, with mean annual net methane fluxes of 8.05 + or{minus}2.50 g CH{sub 4}/sq m and 4.88 + or{minus}0.73 g CH{sub 4}/sq m, respectively. Methane fluxes form the moss sites and intertussock depressions were much lower. Over 90% of the mean annual methane flux from the Eriophorum, intertussock depressions, and Carex sites occurred between thaw and freeze-up. Some 40% of the mean annual methane flux from the moss sites occurred during winter. Composite methane fluxes for tussock tundra and Carex-dominated wet meadow tundra environments were produced by weighting measured component fluxes according to areal coverage. Tussock and wet meadow tundra account for an estimated global methane emission of 19-33 Tg/yr. 39 refs., 7 figs., 2 tabs.

  13. Axially symmetric dissipative fluids in the quasi-static approximation

    NASA Astrophysics Data System (ADS)

    Herrera, L.; di Prisco, A.; Ospino, J.; Carot, J.

    2016-01-01

    Using a framework based on the 1 + 3 formalism, we carry out a study on axially and reflection symmetric dissipative fluids, in the quasi-static regime. We first derive a set of invariantly defined “velocities”, which allow for an inambiguous definition of the quasi-static approximation. Next, we rewrite all the relevant equations in this approximation and extract all the possible, physically relevant, consequences ensuing the adoption of such an approximation. In particular, we show how the vorticity, the shear and the dissipative flux, may lead to situations where different kind of “velocities” change their sign within the fluid distribution with respect to their sign on the boundary surface. It is shown that states of gravitational radiation are not a priori incompatible with the quasi-static regime. However, any such state must last for an infinite period of time, thereby diminishing its physical relevance.

  14. Thermoacoustic mixture separation with an axial temperature gradient

    SciTech Connect

    Geller, Drew W; Swift, Gregory A

    2008-01-01

    The theory of thermoacoustic mixture separation is extended to include the effect of a nonzero axial temperature gradient. The analysis yields a new term in the second-order mole flux that is proportional to the temperature gradient and to the square of the volumetric velocity and is independent of the phasing of the wave. Because of this new term, thermoacoustic separation stops at a critical temperature gradient and changes direction above that gradient. For a traveling wave, this gradient is somewhat higher than that predicted by a simple four-step model. An experiment tests the theory for temperature gradients from 0 to 416 K/m in 50-50 He-Ar mixtures.

  15. Diagnostics Systems for Permanent Hall Thrusters Development

    NASA Astrophysics Data System (ADS)

    Ferreira, Jose Leonardo; Soares Ferreira, Ivan; Santos, Jean; Miranda, Rodrigo; Possa, M. Gabriela

    This work describes the development of Permanent Magnet Hall Effect Plasma Thruster (PHALL) and its diagnostic systems at The Plasma Physics Laboratory of University of Brasilia. The project consists on the construction and characterization of plasma propulsion engines based on the Hall Effect. Electric thrusters have been employed in over 220 successful space missions. Two types stand out: the Hall-Effect Thruster (HET) and the Gridded Ion Engine (GIE). The first, which we deal with in this project, has the advantage of greater simplicity of operation, a smaller weight for the propulsion subsystem and a longer shelf life. It can operate in two configurations: magnetic layer and anode layer, the difference between the two lying in the positioning of the anode inside the plasma channel. A Hall-Effect Thruster-HET is a type of plasma thruster in which the propellant gas is ionized and accelerated by a magneto hydrodynamic effect combined with electrostatic ion acceleration. So the essential operating principle of the HET is that it uses a J x B force and an electrostatic potential to accelerate ions up to high speeds. In a HET, the attractive negative charge is provided by electrons at the open end of the Thruster instead of a grid, as in the case of the electrostatic ion thrusters. A strong radial magnetic field is used to hold the electrons in place, with the combination of the magnetic field and the electrostatic potential force generating a fast circulating electron current, the Hall current, around the axis of the Thruster, mainly composed by drifting electrons in an ion plasma background. Only a slow axial drift towards the anode occurs. The main attractive features of the Hall-Effect Thruster are its simple design and operating principles. Most of the Hall-Effect Thrusters use electromagnet coils to produce the main magnetic field responsible for plasma generation and acceleration. In this paper we present a different new concept, a Permanent Magnet Hall

  16. New permanent magnets; manganese compounds.

    PubMed

    Coey, J M D

    2014-02-12

    The exponential growth of maximum energy product that prevailed in the 20th century has stalled, leaving a market dominated by two permanent magnet materials, Nd2Fe14B and Ba(Sr)Fe12O19, for which the maximum theoretical energy products differ by an order of magnitude (515 kJ m(-3) and 45 kJ m(-3), respectively). Rather than seeking to improve on optimized Nd-Fe-B, it is suggested that some research efforts should be devoted to developing appropriately priced alternatives with energy products in the range 100-300 kJ m(-3). The prospects for Mn-based hard magnetic materials are discussed, based on known Mn-based compounds with the tetragonal L10 or D022 structure or the hexagonal B81 structure.

  17. Permanent deformation of flexible pavements

    NASA Astrophysics Data System (ADS)

    Brown, S. F.; Broderick, B. V.; Pappin, J. W.

    1980-06-01

    Seven pairs of pavements with granular bases were tested under controlled conditions. One pavement in each pair contained fabric inclusions. An improved testing facility was developed, including: (1) servo-hydraulic system for the loading carriage; (2) amplification and read-out system for pressure cells; (3) linearizing unit for strain coils; (4) transducers for measuring vertical and resilient deflection; (5) techniques for measuring in situ strain on fabric inclusions; (6) extensive use of nuclear density meter to monitor pavement and foundation materials. The following conclusions are drawn: (1) No improvement in performance resulted from fabric inclusions. (2) No consistent reduction in in-situ stresses, resilient strains, or permanent strains was observed as a result of fabric inclusion. (3) No consistent improvement in densities resulted from fabric inclusions. (4) Some slip apparently occurred between fabric and soil on those pavements which involved large deformations. The slip occurred between fabric and crushed limestone base rather than between fabric and silty-clay subgrade.

  18. Is CO2 ice permanent?

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1992-01-01

    Carbon dioxide ice has been inferred to exist at the south pole in summertime, but Earth based measurements in 1969 of water vapor in the Martian atmosphere suggest that all CO2 ice sublined from the southern polar cap and exposed underlying water ice. This implies that the observed summertime CO2 ice is of recent origin. It appears possible to construct an energy balance model that maintains seasonal CO2 ice at the south pole year round and still reasonably simulates the polar cap regression and atmospheric pressure data. This implies that the CO2 ice observed in the summertime south polar cap could be seasonal in origin, and that minor changes in climate could cause CO2 ice to completely vanish, as would appear to have happened in 1969. However, further research remains before it is certain whether the CO2 ice observed in the summertime south polar cap is seasonal or is part of a permanent reservoir.

  19. Active H ∞ control of the vibration of an axially moving cantilever beam by magnetic force

    NASA Astrophysics Data System (ADS)

    Wang, Liang; Chen, Huai-hai; He, Xu-dong

    2011-11-01

    An H ∞ method for the vibration control of an iron cantilever beam with axial velocity using the noncontact force by permanent magnets is proposed in the paper. The transverse vibration equation of the axially moving cantilever beam with a tip mass is derived by D'Alembert's principle and then updated by experiments. An experimental platform and a magnetic control system are introduced. The properties of the force between the magnet and the beam have been determined by theoretic analysis and tests. The H ∞ control strategy for the suppression of the beam transverse vibration by initial deformation excitations is put forward. The control method can be used for the beam with constant length or varying length. Numerical simulation and actual experiments are implemented. The results show that the control method is effective and the simulations fit well with the experiments.

  20. Atlanto Axial Rotatory Dislocation in Adults: A Rare Complication of an Epileptic Seizure—Case Report

    PubMed Central

    TARANTINO, Roberto; DONNARUMMA, Pasquale; MAROTTA, Nicola; MISSORI, Paolo; VIOZZI, Ilaria; LANDI, Alessandro; DELFINI, Roberto

    2014-01-01

    Atlanto Axial Rotatory Dislocations (AARDs) are a heterogeneous group of post-traumatic pathologies typical of the pediatric age, and rare in adults. We describe the case of a 34-year-old woman, developing Atlanto Axial Rotatory Fixation (AARF) after a generalized tonic-clonic epileptic seizure, an extremely rare traumatic cause never described in literature. AARF was detected only 1 month after the accident and nonsurgical treatment was attempted at the beginning. The patient underwent surgery only 2 months after the accident. The best treatment should be conservative reduction within 1 month; when it is not possible, it is advisable to perform surgery as soon as possible. C1–C2 fixation with Harm's technique is the gold standard for fixed luxations. Delay of treatment makes intraoperative reduction more difficult and increase the establishment of the chronic permanent change of neck muscles and ligaments. PMID:24201098

  1. Atlanto axial rotatory dislocation in adults: a rare complication of an epileptic seizure--case report.

    PubMed

    Tarantino, Roberto; Donnarumma, Pasquale; Marotta, Nicola; Missori, Paolo; Viozzi, Ilaria; Landi, Alessandro; Delfini, Roberto

    2014-01-01

    Atlanto Axial Rotatory Dislocations (AARDs) are a heterogeneous group of post-traumatic pathologies typical of the pediatric age, and rare in adults. We describe the case of a 34-year-old woman, developing Atlanto Axial Rotatory Fixation (AARF) after a generalized tonic-clonic epileptic seizure, an extremely rare traumatic cause never described in literature. AARF was detected only 1 month after the accident and nonsurgical treatment was attempted at the beginning. The patient underwent surgery only 2 months after the accident. The best treatment should be conservative reduction within 1 month; when it is not possible, it is advisable to perform surgery as soon as possible. C1-C2 fixation with Harm's technique is the gold standard for fixed luxations. Delay of treatment makes intraoperative reduction more difficult and increase the establishment of the chronic permanent change of neck muscles and ligaments.

  2. Alternatives to Rare Earth Permanent Magnets for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Khazdozian, Helena; Hadimani, Ravi; Jiles, David

    Direct-drive permanent magnet generators (DDPMGs) offer increased reliability and efficiency over the more commonly used geared doubly-fed induction generator, yet are only employed in less than 1 percent of utility scale wind turbines in the U.S. One major barrier to increased deployment of DDPMGs in the U.S. wind industry is NdFeB permanent magnets (PMs), which contain critical rare earth elements Nd and Dy. To allow for the use of rare earth free PMs, the magnetic loading, defined as the average magnetic flux density over the rotor surface, must be maintained. Halbach cylinders are employed in 3.5kW Halbach PMGs (HPMGs) of varying slot-to-pole ratio to concentrate the magnetic flux output by a lower energy density PM over the rotor surface. We found that for high pole and slot number, the increase in magnetic loading is sufficient to allow for the use of strontium iron oxide hard ferrite PMs and achieved rated performance. Joule losses in the stator windings were found to increase for the hard ferrite PMs due to increased inductance in the stator windings. However, for scaling of the HPMG designs to 3MW, rated performance and high efficiency were achieved, demonstrating the potential for elimination for rare earth PMs in commercial scale wind turbines. This work was supported by the National Science Foundation under Grant No. 1069283 and a Barbara and James Palmer Endowment at Iowa State University.

  3. A comparative study between axial and radial fluxfocusing magnetic gear topologies and mechanical gearboxes

    NASA Astrophysics Data System (ADS)

    Calvin, Matthew

    A variety of magnetic gear topologies have been investigated in recent years as alternatives to traditional mechanical gearboxes. In general these magnetic gears offer advantages in the non-contact transmission of torque including inherent overload protection, reduced acoustic emissions, and a reduction in the number of contacting components subject to wear. The earliest magnetic gear designs however suffered from low volumetric torque densities, which limited their utility for industrial applications. Research into flux focusing magnetic gearbox topologies has resulted in increased volumetric torque densities by actively engaging all of the magnets in the transmission of torque throughout the process. This research compared the volumetric torque density of axial and radial flux focusing magnetic gearbox designs and prototypes to planetary, cycloidal, and harmonic mechanical gearboxes. The rare earth scaled up radial and axial flux focusing topologies were found to have consistently higher volumetric torque densities than planetary gearboxes of comparable diameter. The cycloidal and harmonic gearboxes had comparable volumetric torque densities, with greater volumetric torque densities for some models and lesser volumetric torque densities for others. The expectation is that further improvements in volumetric torque density are possible for flux focusing magnetic gears with additional refinement and optimization of the designs. The current study does show that flux focusing magnetic gear topologies are a plausible future alternative to mechanical gearboxes in applications where their unique torque transmission mechanism would be advantageous.

  4. Melt-growth bulk superconductors and application to an axial-gap-type rotating machine

    NASA Astrophysics Data System (ADS)

    Zhang, Yufeng; Zhou, Difan; Ida, Tetsuya; Miki, Motohiro; Izumi, Mitsuru

    2016-04-01

    The present manuscript addresses key issues in the course of our study of materials processing of bulk high-temperature superconductors, trapped flux and its application to a prototype axial-gap-type rotating machine. The TUMSAT group has conducted a series of studies since 2003 on the growth of GdBa2Cu3O7-δ bulk material and its application in a compact low-speed high-torque rotating machine. In the stage of material growth, gaining the advantage of a large motive torque density requires large integrated flux in the motor/generators. A large grain surface might be required with sophisticated techniques for the melt-growth texture in the bulk with optimal flux pinning. In the second stage, the in situ magnetization procedure for bulk superconductors in the applied machine is a crucial part of the technology. Pulsed current excitation by using an armature copper winding has magnetized field pole bulks on the rotor. The axial-gap flux synchronous machine studied in the past decade is a condensed technology and indicates that further scientific development is required for a future compact machine to be superior to conventional ones in accordance with the cryogenic periphery and flux stabilization.

  5. Optimization of residual heat removal pump axial thrust and axial bearing

    SciTech Connect

    Schubert, F.

    1996-12-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.

  6. Normal glow discharge in axial magnetic field

    NASA Astrophysics Data System (ADS)

    Surzhikov, S.; Shang, J.

    2014-10-01

    Theory and results of mathematical modeling of a glow discharge in a parallel-plate configuration with axial magnetic field is presented. The model consists of continuity equations for electron and ion fluids, the Poisson equation for the self-consistent electric field. Numerical simulation results are presented for two-dimensional glow discharge at various initial conditions. The results are obtained for molecular nitrogen at pressure 1-5 Torr, emf of power supply 1-2 kV, and magnetic field induction B = 0-0.5 T. It is shown that in the presence of the axial magnetic field the glow discharge is rotated around its axis of symmetry. Nevertheless it is shown that in the investigated range of discharge parameters in an axial magnetic field the law of the normal current density is retained.

  7. Axial flow positive displacement worm gas generator

    NASA Technical Reports Server (NTRS)

    Murrow, Kurt David (Inventor); Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor)

    2010-01-01

    An axial flow positive displacement engine has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first, second, and third sections of a core assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first, second, and third twist slopes in the first, second, and third sections respectively. The first twist slopes are less than the second twist slopes and the third twist slopes are less than the second twist slopes. A combustor section extends axially downstream through at least a portion of the second section.

  8. The magnetic field of a permanent hollow cylindrical magnet

    NASA Astrophysics Data System (ADS)

    Reich, Felix A.; Stahn, Oliver; Müller, Wolfgang H.

    2016-09-01

    Based on the rational version of M AXWELL's equations according to T RUESDELL and T OUPIN or KOVETZ, cf. (Kovetz in Electromagnetic theory, Oxford University Press, Oxford, 2000; Truesdell and Toupin in Handbuch der Physik, Bd. III/1, Springer, Berlin, pp 226-793; appendix, pp 794-858, 2000), we present, for stationary processes, a closed-form solution for the magnetic flux density of a hollow cylindrical magnet. Its magnetization is constant in axial direction. We consider M AXWELL's equations in regular and singular points that are obtained by rational electrodynamics, adapted to stationary processes. The magnetic flux density is calculated analytically by means of a vector potential. We obtain a solution in terms of complete elliptic integrals. Therefore, numerical evaluation can be performed in a computationally efficient manner. The solution is written in dimensionless form and can easily be applied to cylinders of arbitrary shape. The relation between the magnetic flux density and the magnetic field is linear, and an explicit relation for the field is presented. With a slight modification the result can be used to obtain the field of a solid cylindrical magnet. The mathematical structure of the solution and, in particular, singularities are discussed.

  9. Rotor self-lubricating axial stop

    NASA Technical Reports Server (NTRS)

    Blount, Dale H.

    1988-01-01

    A series of lubricating plugs is located in the stationary backup face adjacent to the axial stop face of a rotating impeller mounted in a turbopump for pumping liquid oxygen or liquid hydrogen. The stop face and the backup face are those surfaces which engage when the axial load on the impeller exceeds the load balancing capability. The plugs have a truncated conical configuration so as to be trapped in the backup face, and are placed at varying radii on the face to provide complete surface lubrication. The plugs may be formed from Teflon, Kel-F or bronze filled Teflon.

  10. Rotor self-lubricating axial stop

    NASA Technical Reports Server (NTRS)

    Blount, Dale H. (Inventor)

    1989-01-01

    A plurality of lubricating plugs are disposed in the stationary backup face adjacent to the axial stop face of a rotating impeller mounted in a turbopump for pumping liquid oxygen or liquid hydrogen. The stop face and the backup face are those surfaces which engage when the axial load on the impeller exceeds the load balancing capability. The plugs have a truncated conical configuration so as to be trapped in the backup face, and are disposed at varying radii on the face to provide complete surface lubrication. The plugs may be formed from Teflon, Kel-F or bronze filled Teflon.

  11. Theoretical Determination of Axial Fan Performance

    NASA Technical Reports Server (NTRS)

    Struve, E.

    1943-01-01

    The report presents a method for the computation of axial fan characteristics. The method is based on the assumption that the law of constancy of the circulation along the blade holds, approximately, for all fan conditions for which the blade elements operate at normal angles of attack (up to the stalling angles). Pressure head coefficient K(sub a) and power coefficient K(sub u) for the force components in the axial and tangential directions, respectively, and analogous to the lift and drag coefficients C(sub y) and C(sub x) are conveniently introduced.

  12. High axial load termination for TLP tendons

    SciTech Connect

    Salama, M.M.

    1992-03-03

    This patent describes a hollow high axial load termination for a composite tubular tendon. It comprises: a curved hollow termination body open at one end wit a circular opening and connected at the opposite curved end with an elongated hollow member of lesser diameter than the diameter of the circular opening of the termination body, a composite tubular tendon containing axial fibers and helical fibers laid on an inner hollow liner; fibers of the composite tubular tendon extending over and covering the termination body from the abutment with the composite tubular tendon to the elongated member of lesser diameter than the termination body.

  13. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  14. Fast flux locked loop

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-09-10

    A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.

  15. A theory of rotating stall of multistage axial compressors

    NASA Technical Reports Server (NTRS)

    Moore, F. K.

    1983-01-01

    A theoretical analysis was made of rotating stall in axial compressors of many stages, finding conditions for a permanent, straight-through traveling disturbance, with the steady compressor characteristic assumed known, and with simple lag processes ascribed to the flows in the inlet, blade passages, and exit regions. For weak disturbances, predicted stall propagation speeds agree well with experimental results. For a locally-parabolic compressor characteristic, an exact nonlinear solution is found and discussed. For deep stall, the stall-zone boundary is most abrupt at the trailing edge, as expected. When a complete characteristic having unstalling and reverse-flow features is adopted, limit cycles governed by a Lienard's equation are found. Analysis of these cycles yields predictions of recovery from rotating stall; a relaxation oscillation is found at some limiting flow coefficient, above which no solution exists. Recovery is apparently independent of lag processes in the blade passages, but instead depends on the lags originating in the inlet and exit flows, and also on the shape of the given characteristic diagram. Small external lags and tall diagrams favor early recovery. Implications for future research are discussed.

  16. Enhancing the force capability of permanent magnet latching actuators for electromechanical valve actuation systems

    NASA Astrophysics Data System (ADS)

    Rens, J.; Clark, R. E.; Jewell, G. W.; Howe, D.

    2005-05-01

    This article introduces a topology of parallel-polarized permanent magnet latching actuator for use in electromagnetic valve actuation systems for internal combustion engines. The actuator has a number of advantages over reluctance actuators, commonly employed in such systems, in terms of reduced starting currents and fail-safe capability. The influence of a number of design features on actuator performance, such as tooth tapering, additional magnets to improve the main magnet flux path and prevent the onset of saturation, and mechanical clearances required to protect the permanent magnet from shock loads are investigated. The design study findings are verified by measurements on a prototype actuator.

  17. Permanent magnetic-levitation of rotating impeller: a decisive breakthrough in the centrifugal pump.

    PubMed

    Qian, K X; Zeng, P; Ru, W M; Yuan, H Y; Feng, Z G; Li, L

    2002-01-01

    Magnetic bearings have no mechanical contact between the rotor and stator, and a rotary pump with magnetic bearings therefore has no mechanical wear and thrombosis. The magnetic bearings available, however, contain electromagnets, are complicated to control and have high energy consumption. Therefore, it is difficult to apply an electromagnetic bearing to a rotary pump without disturbing its simplicity, reliability and ability to be implanted. The authors have developed a levitated impeller pump using only permanent magnets. The rotor is supported by permanent radial magnetic forces. The impeller is fixed on one side of the rotor; on the other side the rotor magnets are mounted. Opposite these rotor magents, a driving magnet is fastened to the motor axis. Thereafter, the motor drives the rotor via magnetic coupling. In laboratory tests with saline, where the rotor is still or rotates at under 4,000 rpm, the rotor magnets have one point in contact axially with a spacer between the rotor magnets and the driving magnets. The contacting point is located in the center of the rotor. As the rotating speed increases gradually to more than 4000 rpm, the rotor will disaffiliate from the stator axially, and become fully levitated. Since the axial levitation is produced by hydraulic force and the rotor magnets have a giro-effect, the rotor rotates very stably during levitation. As a left ventricular assist device, the pump works in a rotating speed range of 5,000-8,000 rpm, and the levitation of the impeller is assured by use of the pump. The permanent maglev impeller pump retains the advantages of the rotary pump but overcomes the disadvantages of the leviated pump with electromagnetic-bearing, and has met with most requirements of artificial heart blood pumps, thus promising to have more applications than previously. PMID:11924845

  18. Validation of neutron flux redistribution factors in JSI TRIGA reactor due to control rod movements.

    PubMed

    Kaiba, Tanja; Žerovnik, Gašper; Jazbec, Anže; Štancar, Žiga; Barbot, Loïc; Fourmentel, Damien; Snoj, Luka

    2015-10-01

    For efficient utilization of research reactors, such as TRIGA Mark II reactor in Ljubljana, it is important to know neutron flux distribution in the reactor as accurately as possible. The focus of this study is on the neutron flux redistributions due to control rod movements. For analyzing neutron flux redistributions, Monte Carlo calculations of fission rate distributions with the JSI TRIGA reactor model at different control rod configurations have been performed. Sensitivity of the detector response due to control rod movement have been studied. Optimal radial and axial positions of the detector have been determined. Measurements of the axial neutron flux distribution using the CEA manufactured fission chambers have been performed. The experiments at different control rod positions were conducted and compared with the MCNP calculations for a fixed detector axial position. In the future, simultaneous on-line measurements with multiple fission chambers will be performed inside the reactor core for a more accurate on-line power monitoring system. PMID:26141293

  19. Co-axial, high energy gamma generator

    DOEpatents

    Reijonen, Jani Petteri; Gicquel, Frederic

    2011-08-16

    A gamma ray generator includes an ion source in a first chamber. A second chamber is configured co-axially around the first chamber at a lower second pressure. Co-axially arranged plasma apertures separate the two chambers and provide for restricted passage of ions and gas from the first to the second chamber. The second chamber is formed by a puller electrode having at least one long channel aperture to draw ions from the first chamber when the puller electrode is subject to an appropriate applied potential. A plurality of electrodes rings in the third chamber in third pressure co-axially surround the puller electrode and have at least one channel corresponding to the at least one puller electrode aperture and plasma aperture. The electrode rings increase the energy of the ions to a selected energy in stages in passing between successive pairs of the electrodes by application of an accelerating voltage to the successive pairs of accelerator electrodes. A target disposed co-axially around the plurality of electrodes receives the beam of accelerated ions, producing gamma rays.

  20. Aerodynamic Design of Axial Flow Compressors

    NASA Technical Reports Server (NTRS)

    Bullock, R. O. (Editor); Johnsen, I. A.

    1965-01-01

    An overview of 'Aerodynamic systems design of axial flow compressors' is presented. Numerous chapters cover topics such as compressor design, ptotential and viscous flow in two dimensional cascades, compressor stall and blade vibration, and compressor flow theory. Theoretical aspects of flow are also covered.

  1. Stability of structural members under axial load

    NASA Technical Reports Server (NTRS)

    Lundquist, Eugene E

    1937-01-01

    The principles of the cross method of moment distribution are used to check the stability of structural members under axial load. A brief theoretical treatment of the subject, together with an illustrative problem, is included as well as a discussion of the reduced modulus at high stresses and a set of tables to aid in the solution of practical problems.

  2. On gravitational radiation with axial symmetry

    NASA Astrophysics Data System (ADS)

    Robinson, Ivor

    1989-12-01

    General results are obtained for Robinson-Trautman metrics which satisfy reasonable conditions for radiation from a bounded source. For the axially symmetrical case, the degree of the one field equation is reduced from 5 to 2; a simplified proof is given of the Lukacs-Perjes-Porter-Sebestyen theorem and a systematic procedure is developed for formal solution in series.

  3. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: AXIAL RESOLUTION

    EPA Science Inventory

    Abstract

    Confocal Microscopy System Performance: Axial resolution.
    Robert M. Zucker, PhD

    Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Re...

  4. Hybrid permanent magnet quadrupoles for the Recycler Ring at Fermilab

    SciTech Connect

    Brown, B.C.; Pruss, S.M.; Foster, G.W.; Glass, H.D.; Harding, D.J.; Jackson, G.R.; May, M.R.; Nicol, T.H.; Ostiguy, J.-F.; Schlabach, R.; Volk, J.T.

    1997-10-01

    Hybrid Permanent Magnet Quadrupoles are used in several applications for the Fermilab Recycler Ring and associated beam transfer lines. Most of these magnets use a 0.6096 m long iron shell and provide integrated gradients up to 1.4 T-m/m with an iron pole tip radius of 41.6 mm. A 58.4 mm pole radius design is also required. Bricks of 25. 4 mm thick strontium ferrite supply the flux to the back of the pole to produce the desired gradients (0.6 to 2.75 T/m). For temperature compensation, Ni-Fe alloy strips are interspersed between ferrite bricks to subtract flux in a temperature dependent fashion. Adjustments of the permeance of each pole using iron between the pole and the flux return shell permits the matching of pole potentials. Magnetic potentials of the poles are adjusted to the desired value to achieve the prescribed strength and field uniformity based on rotating coil harmonic measurements. Procurement, fabrication, pole potential adjustment, and measured fields will be reported.

  5. Permanency and the Foster Care System.

    PubMed

    Lockwood, Katie K; Friedman, Susan; Christian, Cindy W

    2015-10-01

    Each year over 20,000 youth age out of the child welfare system without reaching a permanent placement in a family. Certain children, such as those spending extended time in foster care, with a diagnosed disability, or adolescents, are at the highest risk for aging out. As young adults, this population is at and increased risk of incarceration; food, housing, and income insecurity; unemployment; educational deficits; receipt of public assistance; and mental health disorders. We reviewed the literature on foster care legislation, permanency, outcomes, and interventions. The outcomes of children who age out of the child welfare system are poor. Interventions to increase permanency include training programs for youth and foster parents, age extension for foster care and insurance coverage, an adoption tax credit, and specialized services and programs that support youth preparing for their transition to adulthood. Future ideas include expanding mentoring, educational support, mental health services, and post-permanency services to foster stability in foster care placements and encourage permanency planning. Children in the child welfare system are at a high risk for physical, mental, and emotional health problems that can lead to placement instability and create barriers to achieving permanency. Failure to reach the permanency of a family leads to poor outcomes, which have negative effects on the individual and society. Supporting youth in foster care throughout transitions may mediate the negative outcomes that have historically followed placement in out-of-home care. PMID:26403649

  6. Permanency and the Foster Care System.

    PubMed

    Lockwood, Katie K; Friedman, Susan; Christian, Cindy W

    2015-10-01

    Each year over 20,000 youth age out of the child welfare system without reaching a permanent placement in a family. Certain children, such as those spending extended time in foster care, with a diagnosed disability, or adolescents, are at the highest risk for aging out. As young adults, this population is at and increased risk of incarceration; food, housing, and income insecurity; unemployment; educational deficits; receipt of public assistance; and mental health disorders. We reviewed the literature on foster care legislation, permanency, outcomes, and interventions. The outcomes of children who age out of the child welfare system are poor. Interventions to increase permanency include training programs for youth and foster parents, age extension for foster care and insurance coverage, an adoption tax credit, and specialized services and programs that support youth preparing for their transition to adulthood. Future ideas include expanding mentoring, educational support, mental health services, and post-permanency services to foster stability in foster care placements and encourage permanency planning. Children in the child welfare system are at a high risk for physical, mental, and emotional health problems that can lead to placement instability and create barriers to achieving permanency. Failure to reach the permanency of a family leads to poor outcomes, which have negative effects on the individual and society. Supporting youth in foster care throughout transitions may mediate the negative outcomes that have historically followed placement in out-of-home care.

  7. Design of high-perveance confined-flow guns for periodic-permanent-magnet-focused tubes

    NASA Technical Reports Server (NTRS)

    Stankiewicz, N.

    1979-01-01

    An approach to the design of high perveance, low compression guns is described in which confinement is used to stabilize the beam for subsequent periodic-permanent-magnet focusing. The computed results for two cases are presented. A magnetic boundary value problem was solved for the scalar potential from which the axial magnetic field was computed. A solution was found by iterating between Poisson's equation and the electron trajectory calculations. Magnetic field values were varied in magnitude until a laminar beam with minimum scalloping was produced.

  8. Evaluation of Axially Modulations in Plasma Channels

    NASA Astrophysics Data System (ADS)

    Cooley, James; Antonsen, Thomas; Milchberg, Howard; Fan, Jay; Parra, Enrique

    2000-10-01

    Plasma waveguides for guiding intense laser pulses have applications in particle acceleration and x-ray generation schemes. Waveguides can be formed using a variety of methods. One method [1] is to create a plasma channel by breaking down a gas with a laser pulse focused through an axicon. Ideally, the plasma channel will be axially symmetric and allow for guided single mode propagation of short laser pulses. However, for certain experimental conditions the channel develops periodic axial modulations. The onset of these modulations appears to correlate with the conditions for self trapping and resonant absorption of the axicon pulse by the plasma waveguide. Resonant absorption occurs under the following scenario [2]. As the channel is expanding the axial wave numbers of the modes of the leaky waveguide defined by the channel evolve as well. At certain times one of these axial wave numbers will correspond to that of the formation pulse, which is defined by the axicon. At this time the formation pulse couples linearly to the confined mode of the channel and is strongly absorbed. According to our model the modulations are due to a nonlinear coupling of the axicon field to the confined modes of the channel. Small axial modulations in the expansion rate of the channel can scatter the incident axicon field into the guided mode of the waveguide. The beating of the guided mode and the axicon field leads to modulations in the heating rate and ponderomotive force which reinforce the modulations in the expansion rate, in other words, there is a parametric instability. A simple model of this process will be presented. [1] C.G. Durfee III and H.M. Milchberg, Phys. Rev. Lett. 71, 2409 (1993) [2] J. Fan, E. Parra, and H.M. Milchberg, Phys. Rev. Lett. 84, 3085 (2000)

  9. Permanent magnet Hall Thrusters development and applications on future brazilian space missions

    NASA Astrophysics Data System (ADS)

    Ferreira, Jose Leonardo; Martins, Alexandre A.; Miranda, Rodrigo; Schelling, Adriane; de Souza Alves, Lais; Gonçalves Costa, Ernesto; de Oliveira Coelho Junior, Helbert; Castelo Branco, Artur; de Oliveira Lopes, Felipe Nathan

    2015-10-01

    The Plasma Physics Laboratory (PPLUnB) has been developing a Permanent Magnet Hall Thruster (PHALL) for the Space Research Program for Universities (UNIESPAÇO), part of the Brazilian Space Activities Program (PNAE) since 2004. The PHALL project consists on a plasma source design, construction and characterization of the Hall type that will function as a plasma propulsion engine and characterized by several plasma diagnostics sensors. PHALL is based on a plasma source in which a Hall current is generated inside a cylindrical annular channel with an axial electric field produced by a ring anode and a radial magnetic field produced by permanent magnets. In this work it is shown a brief description of the plasma propulsion engine, its diagnostics instrumentation and possible applications of PHALL on orbit transfer maneuvering for future Brazilian geostationary satellite space missions.

  10. Leaf hydraulic conductance for a tank bromeliad: axial and radial pathways for moving and conserving water.

    PubMed

    North, Gretchen B; Lynch, Frank H; Maharaj, Franklin D R; Phillips, Carly A; Woodside, Walter T

    2013-01-01

    Epiphytic plants in the Bromeliaceae known as tank bromeliads essentially lack stems and absorptive roots and instead take up water from reservoirs formed by their overlapping leaf bases. For such plants, leaf hydraulic conductance is plant hydraulic conductance. Their simple strap-shaped leaves and parallel venation make them suitable for modeling leaf hydraulic conductance based on vasculature and other anatomical and morphological traits. Plants of the tank bromeliad Guzmania lingulata were investigated in a lowland tropical forest in Costa Rica and a shaded glasshouse in Los Angeles, CA, USA. Stomatal conductance to water vapor and leaf anatomical variables related to hydraulic conductance were measured for both groups. Tracheid diameters and numbers of vascular bundles (veins) were used with the Hagen-Poiseuille equation to calculate axial hydraulic conductance. Measurements of leaf hydraulic conductance using the evaporative flux method were also made for glasshouse plants. Values for axial conductance and leaf hydraulic conductance were used in a model based on leaky cable theory to estimate the conductance of the radial pathway from the vein to the leaf surface and to assess the relative contributions of both axial and radial pathways. In keeping with low stomatal conductance, low stomatal density, low vein density, and narrow tracheid diameters, leaf hydraulic conductance for G. lingulata was quite low in comparison with most other angiosperms. Using the predicted axial conductance in the leaky cable model, the radial resistance across the leaf mesophyll was predicted to predominate; lower, more realistic values of axial conductance resulted in predicted radial resistances that were closer to axial resistance in their impact on total leaf resistance. Tracer dyes suggested that water uptake through the tank region of the leaf was not limiting. Both dye movement and the leaky cable model indicated that the leaf blade of G. lingulata was structurally and

  11. Leaf hydraulic conductance for a tank bromeliad: axial and radial pathways for moving and conserving water.

    PubMed

    North, Gretchen B; Lynch, Frank H; Maharaj, Franklin D R; Phillips, Carly A; Woodside, Walter T

    2013-01-01

    Epiphytic plants in the Bromeliaceae known as tank bromeliads essentially lack stems and absorptive roots and instead take up water from reservoirs formed by their overlapping leaf bases. For such plants, leaf hydraulic conductance is plant hydraulic conductance. Their simple strap-shaped leaves and parallel venation make them suitable for modeling leaf hydraulic conductance based on vasculature and other anatomical and morphological traits. Plants of the tank bromeliad Guzmania lingulata were investigated in a lowland tropical forest in Costa Rica and a shaded glasshouse in Los Angeles, CA, USA. Stomatal conductance to water vapor and leaf anatomical variables related to hydraulic conductance were measured for both groups. Tracheid diameters and numbers of vascular bundles (veins) were used with the Hagen-Poiseuille equation to calculate axial hydraulic conductance. Measurements of leaf hydraulic conductance using the evaporative flux method were also made for glasshouse plants. Values for axial conductance and leaf hydraulic conductance were used in a model based on leaky cable theory to estimate the conductance of the radial pathway from the vein to the leaf surface and to assess the relative contributions of both axial and radial pathways. In keeping with low stomatal conductance, low stomatal density, low vein density, and narrow tracheid diameters, leaf hydraulic conductance for G. lingulata was quite low in comparison with most other angiosperms. Using the predicted axial conductance in the leaky cable model, the radial resistance across the leaf mesophyll was predicted to predominate; lower, more realistic values of axial conductance resulted in predicted radial resistances that were closer to axial resistance in their impact on total leaf resistance. Tracer dyes suggested that water uptake through the tank region of the leaf was not limiting. Both dye movement and the leaky cable model indicated that the leaf blade of G. lingulata was structurally and

  12. Leaf Hydraulic Conductance for a Tank Bromeliad: Axial and Radial Pathways for Moving and Conserving Water

    PubMed Central

    North, Gretchen B.; Lynch, Frank H.; Maharaj, Franklin D. R.; Phillips, Carly A.; Woodside, Walter T.

    2013-01-01

    Epiphytic plants in the Bromeliaceae known as tank bromeliads essentially lack stems and absorptive roots and instead take up water from reservoirs formed by their overlapping leaf bases. For such plants, leaf hydraulic conductance is plant hydraulic conductance. Their simple strap-shaped leaves and parallel venation make them suitable for modeling leaf hydraulic conductance based on vasculature and other anatomical and morphological traits. Plants of the tank bromeliad Guzmania lingulata were investigated in a lowland tropical forest in Costa Rica and a shaded glasshouse in Los Angeles, CA, USA. Stomatal conductance to water vapor and leaf anatomical variables related to hydraulic conductance were measured for both groups. Tracheid diameters and numbers of vascular bundles (veins) were used with the Hagen–Poiseuille equation to calculate axial hydraulic conductance. Measurements of leaf hydraulic conductance using the evaporative flux method were also made for glasshouse plants. Values for axial conductance and leaf hydraulic conductance were used in a model based on leaky cable theory to estimate the conductance of the radial pathway from the vein to the leaf surface and to assess the relative contributions of both axial and radial pathways. In keeping with low stomatal conductance, low stomatal density, low vein density, and narrow tracheid diameters, leaf hydraulic conductance for G. lingulata was quite low in comparison with most other angiosperms. Using the predicted axial conductance in the leaky cable model, the radial resistance across the leaf mesophyll was predicted to predominate; lower, more realistic values of axial conductance resulted in predicted radial resistances that were closer to axial resistance in their impact on total leaf resistance. Tracer dyes suggested that water uptake through the tank region of the leaf was not limiting. Both dye movement and the leaky cable model indicated that the leaf blade of G. lingulata was structurally and

  13. Permanent multipole magnets with adjustable strength

    SciTech Connect

    Halbach, K.

    1983-03-01

    Preceded by a short discussion of the motives for using permanent magnets in accelerators, a new type of permanent magnet for use in accelerators is presented. The basic design and most important properties of a quadrupole will be described that uses both steel and permanent magnet material. The field gradient produced by this magnet can be adjusted without changing any other aspect of the field produced by this quadrupole. The generalization of this concept to produce other multipole fields, or combination of multipole fields, will also be presented.

  14. Magnetic-flux pump

    NASA Technical Reports Server (NTRS)

    Hildebrandt, A. F.; Elleman, D. D.; Whitmore, F. C. (Inventor)

    1966-01-01

    A magnetic flux pump is described for increasing the intensity of a magnetic field by transferring flux from one location to the magnetic field. The device includes a pair of communicating cavities formed in a block of superconducting material, and a piston for displacing the trapped magnetic flux into the secondary cavity producing a field having an intense flux density.

  15. Axial type self-bearing motor for axial flow blood pump.

    PubMed

    Okada, Yohji; Masuzawa, Toru; Matsuda, Ken-Ichi; Ohmori, Kunihiro; Yamane, Takashi; Konishi, Yoshiaki; Fukahori, Shinya; Ueno, Satoshi; Kim, Seung-Jong

    2003-10-01

    An axial self-bearing motor is proposed which can drive an axial blood pump without physical contact. It is a functional combination of the bi-directional disc motor and the axial active magnetic bearing, where it actively controls single degree-of-freedom motion, while other motions such as lateral vibration are passively stable. For application to a blood pump, the proposed self-bearing motor has the advantages of simple structure and small size. Through the finite element method (FEM) analysis and the experimental test, its good feasibility is verified. Finally, the axial flow pump is fabricated using the developed magnetically suspended motor. The pump test is carried out and the results are discussed in detail. PMID:14616531

  16. Characterizing hydrologic permanence in headwater streams

    EPA Science Inventory

    The presentation will be an overview of research to inform jurisdictional determinations for the Clean Water Act, in particular research that hydrographic comparisons of the extent and hydrologic permanence of headwater streams, indicator development, and an evaluation of a rapid...

  17. Nonuniform radiation damage in permanent magnet quadrupoles

    SciTech Connect

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.

    2014-08-15

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  18. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, R.O.

    1997-01-21

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis. 10 figs.

  19. Sporadic hemiplegic migraine with permanent neurological deficits.

    PubMed

    Schwedt, Todd J; Zhou, Jiying; Dodick, David W

    2014-01-01

    By definition, the neurologic impairments of hemiplegic migraine are reversible. However, a few cases of permanent neurologic deficits associated with hemiplegic migraine have been reported. Herein, we present the case of a patient with permanent impairments because of hemiplegic migraine despite normalization of associated brain magnetic resonance imaging abnormalities. Cases like these suggest the need to consider aggressive prophylactic therapy for patients with recurrent hemiplegic migraine attacks.

  20. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, Roman O.

    1997-01-01

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.

  1. Permanent education in health: a review

    PubMed Central

    Miccas, Fernanda Luppino; Batista, Sylvia Helena Souza da Silva

    2014-01-01

    OBJECTIVE To undertake a meta-synthesis of the literature on the main concepts and practices related to permanent education in health. METHODS A bibliographical search was conducted for original articles in the PubMed, Web of Science, LILACS, IBECS and SciELO databases, using the following search terms: “public health professional education”, “permanent education”, “continuing education”, “permanent education health”. Of the 590 articles identified, after applying inclusion and exclusion criteria, 48 were selected for further analysis, grouped according to the criteria of key elements, and then underwent meta-synthesis. RESULTS The 48 original publications were classified according to four thematic units of key elements: 1) concepts, 2) strategies and difficulties, 3) public policies and 4) educational institutions. Three main conceptions of permanent education in health were found: problem-focused and team work, directly related to continuing education and education that takes place throughout life. The main strategies for executing permanent education in health are discussion, maintaining an open space for permanent education, and permanent education clusters. The most limiting factor is mainly related to directly or indirect management. Another highlight is the requirement for implementation and maintenance of public policies, and the availability of financial and human resources. The educational institutions need to combine education and service aiming to form critical-reflexive graduates. CONCLUSIONS The coordination between health and education is based as much on the actions of health services as on management and educational institutions. Thus, it becomes a challenge to implement the teaching-learning processes that are supported by critical-reflexive actions. It is necessary to carry out proposals for permanent education in health involving the participation of health professionals, teachers and educational institutions. PMID:24789649

  2. Quantum Permanents and Hafnians via Pfaffians

    NASA Astrophysics Data System (ADS)

    Jing, Naihuan; Zhang, Jian

    2016-10-01

    Quantum determinants and Pfaffians or permanents and Hafnians are introduced on the two-parameter quantum general linear group. Fundamental identities among quantum Pf, Hf, and det are proved in the general setting. We show that there are two special quantum algebras among the quantum groups, where the quantum Pfaffians have integral Laurent polynomials as coefficients. As a consequence, the quantum Hafnian is computed by a closely related quantum permanent and identical to the quantum Pfaffian on this special quantum algebra.

  3. Three-Dimensional Field Solutions for Multi-Pole Cylindrical Halbach Arrays in an Axial Orientation

    NASA Technical Reports Server (NTRS)

    Thompson, William K.

    2006-01-01

    This article presents three-dimensional B field solutions for the cylindrical Halbach array in an axial orientation. This arrangement has applications in the design of axial motors and passive axial magnetic bearings and couplers. The analytical model described here assumes ideal magnets with fixed and uniform magnetization. The field component functions are expressed as sums of 2-D definite integrals that are easily computed by a number of mathematical analysis software packages. The analysis is verified with sample calculations and the results are compared to equivalent results from traditional finite-element analysis (FEA). The field solutions are then approximated for use in flux linkage and induced EMF calculations in nearby stator windings by expressing the field variance with angular displacement as pure sinusoidal function whose amplitude depends on radial and axial position. The primary advantage of numerical implementation of the analytical approach presented in the article is that it lends itself more readily to parametric analysis and design tradeoffs than traditional FEA models.

  4. A double-sided linear primary permanent magnet vernier machine.

    PubMed

    Du, Yi; Zou, Chunhua; Liu, Xianxing

    2015-01-01

    The purpose of this paper is to present a new double-sided linear primary permanent magnet (PM) vernier (DSLPPMV) machine, which can offer high thrust force, low detent force, and improved power factor. Both PMs and windings of the proposed machine are on the short translator, while the long stator is designed as a double-sided simple iron core with salient teeth so that it is very robust to transmit high thrust force. The key of this new machine is the introduction of double stator and the elimination of translator yoke, so that the inductance and the volume of the machine can be reduced. Hence, the proposed machine offers improved power factor and thrust force density. The electromagnetic performances of the proposed machine are analyzed including flux, no-load EMF, thrust force density, and inductance. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed.

  5. A double-sided linear primary permanent magnet vernier machine.

    PubMed

    Du, Yi; Zou, Chunhua; Liu, Xianxing

    2015-01-01

    The purpose of this paper is to present a new double-sided linear primary permanent magnet (PM) vernier (DSLPPMV) machine, which can offer high thrust force, low detent force, and improved power factor. Both PMs and windings of the proposed machine are on the short translator, while the long stator is designed as a double-sided simple iron core with salient teeth so that it is very robust to transmit high thrust force. The key of this new machine is the introduction of double stator and the elimination of translator yoke, so that the inductance and the volume of the machine can be reduced. Hence, the proposed machine offers improved power factor and thrust force density. The electromagnetic performances of the proposed machine are analyzed including flux, no-load EMF, thrust force density, and inductance. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed. PMID:25874250

  6. Zeeman slowers for strontium based on permanent magnets

    NASA Astrophysics Data System (ADS)

    Hill, Ian R.; Ovchinnikov, Yuri B.; Bridge, Elizabeth M.; Curtis, E. Anne; Gill, Patrick

    2014-04-01

    We present the design, construction, and characterization of longitudinal- and transverse-field Zeeman slowers, based on arrays of permanent magnets, for slowing thermal beams of atomic Sr. The slowers are optimized for operation with deceleration related to the local laser intensity (by the parameter ɛ), which uses more effectively the available laser power, in contrast to the usual constant deceleration mode. Slowing efficiencies of up to ≈18% are realized and compared to those predicted by modelling. We highlight the transverse-field slower, which is compact, highly tunable, light-weight, and requires no electrical power, as a simple solution to slowing Sr, well-suited to space-borne application. For 88Sr we achieve a slow-atom flux of around 6 × 109 atoms s-1 at 30 ms-1, loading approximately 5 × 108 atoms in to a magneto-optical-trap, and capture all isotopes in approximate relative natural abundances.

  7. A Double-Sided Linear Primary Permanent Magnet Vernier Machine

    PubMed Central

    2015-01-01

    The purpose of this paper is to present a new double-sided linear primary permanent magnet (PM) vernier (DSLPPMV) machine, which can offer high thrust force, low detent force, and improved power factor. Both PMs and windings of the proposed machine are on the short translator, while the long stator is designed as a double-sided simple iron core with salient teeth so that it is very robust to transmit high thrust force. The key of this new machine is the introduction of double stator and the elimination of translator yoke, so that the inductance and the volume of the machine can be reduced. Hence, the proposed machine offers improved power factor and thrust force density. The electromagnetic performances of the proposed machine are analyzed including flux, no-load EMF, thrust force density, and inductance. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed. PMID:25874250

  8. Validation of an axial flow blood pump: computational fluid dynamics results using particle image velocimetry.

    PubMed

    Su, Boyang; Chua, Leok Poh; Wang, Xikun

    2012-04-01

    A magnetically suspended axial flow blood pump is studied experimentally in this article. The pump casing enclosed a three-blade straightener, a two-blade impeller shrouded by a permanent magnet-embedded cylinder, and a three-blade diffuser. The internal flow fields were simulated earlier using computational fluid dynamics (CFD), and the pump characteristic curves were determined. The simulation results showed that the internal flow field was basically streamlined, except the diffuser region. Particle image velocimetry (PIV) measurement of the 1:1 pump model was conducted to validate the CFD result. In order to ensure the optical access, an acrylic prototype was fabricated with the impeller driven by a servomotor instead, as the magnet is opaque. In addition to the transparent model, the blood analog fluid with the refractive index close to that of acrylic was used to avoid refraction. According to the CFD results, the axial flow blood pump could generate adequate pressure head at the rotating speed of 9500rpm and flow rate of 5L/min, and the same flow condition was applied during the PIV measurement. Through the comparisons, it was found that the experimental results were close to those obtained by CFD and had thus validated the CFD model, which could complement the limitation of the measurement in assessing the more detailed flow fields of the axial flow pump.

  9. EDITORIAL: Permanent revolution - or evolution?

    NASA Astrophysics Data System (ADS)

    Dobson, Ken

    1998-03-01

    Honorary Editor It was that temporary Bolshevik Leon Trotsky who developed the principle of `permanent revolution', a principle that perhaps characterizes the recent history of education in (south) Britain more than does, say, principles traditionally associated with the Conservative or Labour parties. As this editorial is being written, changes are being made to primary school education, and the long-awaited details of the post-Dearing reorganizing of post-16 education are yet to hit the overful bookshelves and filing cabinets of school heads and examination board officials. But something unique has happened recently which might have surprised even Trotsky. The Secretary of State for Education has set up targets for primary school pupils' attainment and threatened (or promised) to resign if they are not met within the lifetime of our newly elected parliament. Of course, if Mr Blunkett is still in a position to resign at that stage he will have been the longest serving Secretary of State since time immemorial. But we should not carp: this is truly a revolutionary idea. Not the promise to resign - although this idea is not so fashionable now as it once was. The revolutionary idea is that a major change to an educational process is actually being made that carries with it a predicted and testable outcome. By contrast, when school physics was refreshed a generation ago by the introduction of Nuffield courses at both pre- and post-16 stages, no `targets' were set. I and many other physics teachers certainly preferred teaching these to teaching their predecessor syllabuses, and might even dare to assert that the pupils liked them too. But we still don't really know whether or not they learned more - or even better - physics. Very little happened as far as the outside world was concerned: the usual fraction of students gave up physics at the usual ages, and those who were examined didn't really get a better reward for their more up-to-date and more enjoyably learned

  10. Review of Axial Burnup Distribution Considerations for Burnup Credit Calculations

    SciTech Connect

    Wagner, J.C.; DeHart, M.D.

    2000-03-01

    This report attempts to summarize and consolidate the existing knowledge on axial burnup distribution issues that are important to burnup credit criticality safety calculations. Recently released Nuclear Regulatory Commission (NRC) staff guidance permits limited burnup credit, and thus, has prompted resolution of the axial burnup distribution issue. The reactivity difference between the neutron multiplication factor (keff) calculated with explicit representation of the axial burnup distribution and keff calculated assuming a uniform axial burnup is referred to as the ``end effect.'' This end effect is shown to be dependent on many factors, including the axial-burnup profile, total accumulated burnup, cooling time, initial enrichment, assembly design, and the isotopics considered (i.e., actinide-only or actinides plus fission products). Axial modeling studies, efforts related to the development of axial-profile databases, and the determination of bounding axial profiles are also discussed. Finally, areas that could benefit from further efforts are identified.

  11. Method for providing slip energy control in permanent magnet electrical machines

    DOEpatents

    Hsu, John S.

    2006-11-14

    An electric machine (40) has a stator (43), a permanent magnet rotor (38) with permanent magnets (39) and a magnetic coupling uncluttered rotor (46) for inducing a slip energy current in secondary coils (47). A dc flux can be produced in the uncluttered rotor when the secondary coils are fed with dc currents. The magnetic coupling uncluttered rotor (46) has magnetic brushes (A, B, C, D) which couple flux in through the rotor (46) to the secondary coils (47c, 47d) without inducing a current in the rotor (46) and without coupling a stator rotational energy component to the secondary coils (47c, 47d). The machine can be operated as a motor or a generator in multi-phase or single-phase embodiments and is applicable to the hybrid electric vehicle. A method of providing a slip energy controller is also disclosed.

  12. Study of internal permanent magnet rotor made of 0.6C-13Cr-Fe dual state magnetic material

    NASA Astrophysics Data System (ADS)

    Mita, Masahiro; Masuzawa, Masahiro; Hirao, Noriyoshi; Kimura, Fumio

    2003-05-01

    We have successfully developed an internal permanent magnet (IPM) rotor using dual state bulk magnetic material to increase usable magnetic flux dramatically. The most significant benefit of the IPM rotor is its mechanical reliability, because permanent magnets are inserted in slots of soft magnetic material. On the other hand, there is significant leakage flux between adjoining permanent magnets in the soft magnetic rotor core, reducing the usable magnetic flux flowing into the stator core. To solve this problem, we used a dual state magnetic material, 0.6C-13Cr-Fe alloy. This soft magnetic material could locally be changed into nonmagnetic material by localized heat treatment. By changing the material at leakage flux path into nonmagnetic, we can reduce the leakage flux, while keeping the rotor mechanically sound. By applying the dual state magnetic material to an experimental eight pole IPM rotor, the useful flux flowing in the stator core differs by 8% when compared to an all soft magnetic rotor core.

  13. Microwave axial dielectric properties of carbon fiber.

    PubMed

    Hong, Wen; Xiao, Peng; Luo, Heng; Li, Zhuan

    2015-01-01

    Randomly distributed carbon fibers (CFs) reinforced epoxy resin composites are prepared by the pouring method, the dielectric properties of CF composites with different fiber content and length have been performed in the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the composite increases with the fiber length, which is attributed to the decrease of depolarization field, and increases with the volume fraction, which is attributed to the increase of polarization. A formula, based on the theory of Reynolds-Hugh, is proposed to calculate the effective permittivity of CF composites, and validated by the experiments. The proposed formula is further applied to derive the axial permittivity of CF and analyze the effect of fiber length on the axial permittivity. PMID:26477579

  14. Microwave axial dielectric properties of carbon fiber

    PubMed Central

    Hong, Wen; Xiao, Peng; Luo, Heng; Li, Zhuan

    2015-01-01

    Randomly distributed carbon fibers (CFs) reinforced epoxy resin composites are prepared by the pouring method, the dielectric properties of CF composites with different fiber content and length have been performed in the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the composite increases with the fiber length, which is attributed to the decrease of depolarization field, and increases with the volume fraction, which is attributed to the increase of polarization. A formula, based on the theory of Reynolds-Hugh, is proposed to calculate the effective permittivity of CF composites, and validated by the experiments. The proposed formula is further applied to derive the axial permittivity of CF and analyze the effect of fiber length on the axial permittivity. PMID:26477579

  15. Piping inspection carriage having axially displaceable sensor

    DOEpatents

    Zollinger, W.T.; Treanor, R.C.

    1994-12-06

    A pipe inspection instrument carriage is described for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a Y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure. 4 figures.

  16. Piping inspection carriage having axially displaceable sensor

    DOEpatents

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe inspection instrument carriage for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

  17. Induced axial oscillations in superconducting dipole windings

    SciTech Connect

    Sampson, W.B.; Ghosh, A.K.

    1994-12-31

    When superconducting accelerator magnets wound from multi-stranded conductor are energized a periodic variation appears in the magnetic field along the axis. This oscillation is present in al components of the field and has a period that is equal to the transposition pitch of the superconducting cable. Such axial variations have been observed even in windings which are not carrying any transport current. A magnetic field was applied to a portion of a dipole winding using a second magnet. Axial oscillations were induced along the total length of the windings including the portion not in the applied field. The amplitude of these oscillations varied with the amount of inert winding inside the energizing magnet and with t;he angle of the applied field. These field variations could be completely applied field. These field variations could be completely eliminated in the external portion of the coil by heating a small section of the winding above the transition temperature.

  18. Axial flow positive displacement worm compressor

    NASA Technical Reports Server (NTRS)

    Murrow, Kurt David (Inventor); Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor)

    2010-01-01

    An axial flow positive displacement compressor has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first and second sections of a compressor assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first and second twist slopes in the first and second sections respectively. The first twist slopes are less than the second twist slopes. An engine including the compressor has in downstream serial flow relationship from the compressor a combustor and a high pressure turbine drivingly connected to the compressor by a high pressure shaft.

  19. Microwave axial dielectric properties of carbon fiber

    NASA Astrophysics Data System (ADS)

    Hong, Wen; Xiao, Peng; Luo, Heng; Li, Zhuan

    2015-10-01

    Randomly distributed carbon fibers (CFs) reinforced epoxy resin composites are prepared by the pouring method, the dielectric properties of CF composites with different fiber content and length have been performed in the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the composite increases with the fiber length, which is attributed to the decrease of depolarization field, and increases with the volume fraction, which is attributed to the increase of polarization. A formula, based on the theory of Reynolds-Hugh, is proposed to calculate the effective permittivity of CF composites, and validated by the experiments. The proposed formula is further applied to derive the axial permittivity of CF and analyze the effect of fiber length on the axial permittivity.

  20. Inclination flattening and the geocentric axial dipole hypothesis [rapid communication

    NASA Astrophysics Data System (ADS)

    Tauxe, Lisa

    2005-05-01

    William Gilbert first articulated what has come to be known as the geocentric axial dipole hypothesis. The GAD hypothesis is the principle on which paleogeographic reconstructions rely to constrain paleolatitude. For decades, there have been calls for permanent non-dipole contributions to the time-averaged field. Recently, these have demanded large contributions of the axial octupole, which, if valid, would call into question the general utility of the GAD hypothesis. In the process of geological recording of the geomagnetic field, "Earth filters" distort the directions. Many processes, for example, sedimentary inclination flattening and random tilting, can lead to a net shallowing of the observed direction. Therefore, inclinations that are shallower than expected from GAD can be explained by recording biases, northward transport, or non-dipole geomagnetic fields. Using paleomagnetic data from the last 5 million years from well-constrained lava flow data allows the construction of a statistical geomagnetic field model. Such a model can predict not only the average expected direction for a given latitude, but also the shape of the distribution of directions produced by secular variation. The elongation of predicted directions varies as a function of latitude (from significantly elongate in the up/down direction at the equator to circularly symmetric at the poles). Sedimentary inclination flattening also works in a predictable manner producing elongations that are stretched side to side and the degree of flattening depending on the inclination of the applied field and a "flattening factor" f. The twin tools of the predicted elongation/inclination relationship characteristic of the geomagnetic field for the past 5 million years and the distortion of the directions predicted from sedimentary inclination flattening allows us to find the flattening factor that yields corrected directions with an elongation and average inclination consistent with the statistical field

  1. Cyclotron axial ion-beam-buncher system

    SciTech Connect

    Hamm, R.W.; Swenson, D.A.; Wangler, T.P.

    1982-02-11

    Adiabatic ion bunching is achieved in a cyclotron axial ion injection system through the incorporation of a radio frequency quadrupole system, which receives ions from an external ion source via an accelerate-decelerate system and a focusing einzel lens system, and which adiabatically bunches and then injects the ions into the median plane of a cyclotron via an electrostatic quadrupole system and an inflection mirror.

  2. Atlanto-axial subluxation: a case report

    PubMed Central

    Thurlow, Robert D

    1988-01-01

    One of the causes of death in rheumatoid patients is cord compression following atlanto-axial subluxation. Dislocations in the cervical spine are common with patients who have rheumatoid arthritis. Anterior subluxation occurs in up to 35%, followed by vertical subluxation in 22.2%, lateral subluxation in 20.6% and rarely posterior subluxation. A case report is presented to illustrate such a complication. ImagesFigure 1Figure 2Figure 3Figure 4

  3. Flux-p: automating metabolic flux analysis.

    PubMed

    Ebert, Birgitta E; Lamprecht, Anna-Lena; Steffen, Bernhard; Blank, Lars M

    2012-11-12

    Quantitative knowledge of intracellular fluxes in metabolic networks is invaluable for inferring metabolic system behavior and the design principles of biological systems. However, intracellular reaction rates can not often be calculated directly but have to be estimated; for instance, via 13C-based metabolic flux analysis, a model-based interpretation of stable carbon isotope patterns in intermediates of metabolism. Existing software such as FiatFlux, OpenFLUX or 13CFLUX supports experts in this complex analysis, but requires several steps that have to be carried out manually, hence restricting the use of this software for data interpretation to a rather small number of experiments. In this paper, we present Flux-P as an approach to automate and standardize 13C-based metabolic flux analysis, using the Bio-jETI workflow framework. Exemplarily based on the FiatFlux software, it demonstrates how services can be created that carry out the different analysis steps autonomously and how these can subsequently be assembled into software workflows that perform automated, high-throughput intracellular flux analysis of high quality and reproducibility. Besides significant acceleration and standardization of the data analysis, the agile workflow-based realization supports flexible changes of the analysis workflows on the user level, making it easy to perform custom analyses.

  4. Vibration of axially loaded circular arches

    SciTech Connect

    Sabir, A.B.; Djoudi, M.S.

    1996-11-01

    The work in the present paper is devoted to the determination of the buckling loads and natural frequencies of axially loaded arch structures. The finite element method is employed using a strain based arch element. The element is based on the conventional Euler curved beam type of strain displacement relationship and satisfies the exact representation of rigid body modes. The sub-space iteration technique is used to determine the eigenvalues and corresponding eigenvectors of the governing transcendental equation. The buckling of a pinned arch subjected to a uniform lateral pressure is first considered. The work is then extended to produce a comprehensive set of results for the vibration of axially loaded arches which are either pinned or fixed at both ends. The first symmetric and anti symmetric modes of vibration are determined and the effect of the axial load on these frequencies is investigated. The practical problem of an arch with a backfill is then considered and the effect of the elastic packing due to this backfill on the natural frequencies is determined.

  5. Golimumab for the treatment of axial spondyloarthritis.

    PubMed

    Gelfer, Gita; Perry, Lisa; Deodhar, Atul

    2016-01-01

    Axial spondyloarthritis (axSpA) is a chronic, immune-mediated inflammatory disease of the axial skeleton that includes ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA). Patients with AS experience chronic pain due to sacroiliac joint and spinal inflammation, and may develop spinal ankylosing with syndesmophyte formation. Tumor necrosis factor α inhibitors (TNFi) have shown promise in the management of AS and axSpA by targeting the underlying inflammatory process, and providing symptomatic relief. Whether they alter the progression of the disease is uncertain. Golimumab is a fully human IgG1 monoclonal antibody that targets and downregulates the pro-inflammatory cytokine TNF-α. The use of golimumab has been shown to reduce the signs and symptoms of axSpA as well as improve patient function and quality reported outcomes. This review focuses on the biological rationale and the results of clinical trials with golimumab for the treatment of axSpA.

  6. Bessel beam CARS of axially structured samples

    PubMed Central

    Heuke, Sandro; Zheng, Juanjuan; Akimov, Denis; Heintzmann, Rainer; Schmitt, Michael; Popp, Jürgen

    2015-01-01

    We report about a Bessel beam CARS approach for axial profiling of multi-layer structures. This study presents an experimental implementation for the generation of CARS by Bessel beam excitation using only passive optical elements. Furthermore, an analytical expression is provided describing the generated anti-Stokes field by a homogeneous sample. Based on the concept of coherent transfer functions, the underling resolving power of axially structured geometries is investigated. It is found that through the non-linearity of the CARS process in combination with the folded illumination geometry continuous phase-matching is achieved starting from homogeneous samples up to spatial sample frequencies at twice of the pumping electric field wave. The experimental and analytical findings are modeled by the implementation of the Debye Integral and scalar Green function approach. Finally, the goal of reconstructing an axially layered sample is demonstrated on the basis of the numerically simulated modulus and phase of the anti-Stokes far-field radiation pattern. PMID:26046671

  7. Bessel beam CARS of axially structured samples

    NASA Astrophysics Data System (ADS)

    Heuke, Sandro; Zheng, Juanjuan; Akimov, Denis; Heintzmann, Rainer; Schmitt, Michael; Popp, Jürgen

    2015-06-01

    We report about a Bessel beam CARS approach for axial profiling of multi-layer structures. This study presents an experimental implementation for the generation of CARS by Bessel beam excitation using only passive optical elements. Furthermore, an analytical expression is provided describing the generated anti-Stokes field by a homogeneous sample. Based on the concept of coherent transfer functions, the underling resolving power of axially structured geometries is investigated. It is found that through the non-linearity of the CARS process in combination with the folded illumination geometry continuous phase-matching is achieved starting from homogeneous samples up to spatial sample frequencies at twice of the pumping electric field wave. The experimental and analytical findings are modeled by the implementation of the Debye Integral and scalar Green function approach. Finally, the goal of reconstructing an axially layered sample is demonstrated on the basis of the numerically simulated modulus and phase of the anti-Stokes far-field radiation pattern.

  8. Turbulence Effects of Axial Flow Hydrokinetic Turbines

    NASA Astrophysics Data System (ADS)

    Hill, C.; Chamorro, L. P.; Neary, V. S.; Morton, S.; Sotiropoulos, F.

    2011-12-01

    Axial flow hydrokinetic turbines provide a method for extracting the kinetic energy available in unidirectional (river), bidirectional (tidal) and marine currents; however, a deep understanding of the wake dynamics, momentum recovery, geomorphologic effects, and ecological interaction with these hydrokinetic turbines is required to guarantee their economical and environmental viability. The St. Anthony Falls Laboratory (SAFL) at the University of Minnesota (UMN) has performed physical modeling experiments using a 1:10 scale axial flow tidal turbine in the SAFL Main Channel, a 2.75m x 1.8m x 80m open channel test facility. A sophisticated control system allows synchronous measurements of turbine torque and rotational speed along with high resolution 3-D velocity measurements within the channel. Using acoustic Doppler velocimeters (ADVs), high resolution 3-D velocity profile data were collected up to 15 turbine diameters downstream of the turbine location. These data provide valuable information on the wake characteristics (turbulence, Reynolds stresses, etc.) resulting from a rotating axial flow hydrokinetic machine. Regions of high turbulence and shear zones that persist in the near wake regions are delineated along with the velocity deficit and momentum recovery within the wake downstream of the device. Synchronous ADV data shed light on the rotational and meandering characteristics of the wake and its potential impacts on the local geomorphology and hydrodynamic environment. This dataset on single hydrokinetic turbine flow characteristics is the basis for further work on the optimal arrangement and performance environment for arrays of similar hydrokinetic devices.

  9. Axial Dispersion during Hanford Saltcake Washing

    SciTech Connect

    Josephson, Gary B.; Geeting, John GH; Lessor, Delbert L.; Barton, William B.

    2006-08-01

    Clean up of Hanford salt cake wastes begins with dissolution retrieval of the sodium rich salts that make up the dominant majority of mass in the tanks. Water moving through the porous salt cake dissolves the soluble components and also displaces the soluble radionuclides (e.g. 137Cs and 99TcO4- ). The separation that occurs from this displacement, known as Selective dissolution, is an important component in Hanford’s pretreatment of low activity wastes for subsequent Supplemental treatment. This paper describes lab scale testing conducted to evaluate Selective dissolution of cesium from non-radioactive Hanford tank 241-S-112 salt cake simulant containing the primary chemicals found the the actual tank. An modified axial dispersion model with increasing axial dispersion was developed to predict cesium removal. The model recognizes that water dissolves the salt cake during washing, which causes an increase in the axial dispersion during the wash. This model was subsequently compared with on-line cesium measurements from the retrieval of tank 241-S-112. The model had remarkably good agreement with both the lab scale and full scale data.

  10. Characterization of Active Hydrothermal Fluid Discharge and Recharge Zones in the Endeavour Axial Valley, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Salmi, M.; Hutnak, M.; Hearn, C.; Tivey, M.; Bjorklund, T.; Johnson, H. P.

    2012-12-01

    Sites where warm hydrothermal fluid vents at mid-ocean spreading centers are important for understanding a wide range of critical oceanic processes, but discharge zones represent a very limited portion of crustal fluid circulation pathways. Mapping the distribution of both fluid recharge and discharge sites within the axial valley provides wider insight into the larger scale features of hydrothermal circulation. Our 2011 survey consisted of 180 conductive heat flow stations within the Endeavour axial valley in roughly a 400 m by 1000 m grid, extending across the entire axial valley from the outer flank of the western boundary ridge to the eastern wall. Data acquisition used thermal blankets which measured conductive heat flow without requiring substantial sediment cover. A surprising result from this survey was zones of high heat flow extending across-strike, from the summit of the west valley wall across the entire axial valley floor. This trend was correlated with anomalously low seafloor magnetization from a near-bottom survey with the ROV JASON. Unexpectedly, over half of the axial valley floor was anomalously low at <50 mW m-2, while a small portion of the sites within the 'warm zone' had heat flow values >1 W m-2. The areas of extremely low heat flow values are interpreted as being directly influenced by recharge zones. Based on MCS estimates of partial melt depth below the axial valley and the assumption of no fluid advection, the purely conductive heat flow for this region should be on the order of 1 W m-2.The observation that conductive heat flux is suppressed over large portions of the axial valley floor suggests that heat transfer within the crustal sub-surface fluid reservoir is widespread, and impacts a large portion of our survey area. The largely bi-modal distribution of high and low conductive heat flow, coupled with geophysical and video observations, suggest current Endeavour axial valley crustal fluid circulation models need to be re-evaluated.

  11. Wide gap, permanent magnet biased magnetic bearing system

    NASA Technical Reports Server (NTRS)

    Boden, Karl

    1992-01-01

    The unique features and applications of the presented electrical permanent magnetic bearing system essentially result from three facts: (1) the only bearing rotor components are nonlaminated ferromagnetic steel collars or cylinders; (2) all radial and axial forces are transmitted via radial gaps; and (3) large radial bearing gaps can be provided with minimum electric power consumption. The large gaps allow for effective encapsulation and shielding of the rotors at elevated or low temperatures, corrosive or ultra clean atmosphere or vacuum or high pressure environment. Two significant applications are described: (1) a magnetically suspended x ray rotary anode was operated under high vacuum conditions at 100 KV anode potential, 600 C temperature at the rotor collars and speed 18000 rpm with 13 mm radial bearing gap; and (2) an improved Czochralski type crystal growth apparatus using the hot wall method for pulling GaAs single crystals of low dislocation density. Both crystal and crucible are carried and transported by magnetically suspended shafts inside a hermetically sealed housing at 800 C shaft and wall temperature. The radial magnetic bearing gap measures 24 mm.

  12. Simulating Idealized Flux Ropes with the Flux Rope Insertion Method: A Parameter Space Exploration of Currents and Topology

    NASA Astrophysics Data System (ADS)

    Savcheva, Antonia; Tassev, Svetlin; DeLuca, Edward E.; Gibson, Sarah; Fan, Yuhong

    2016-05-01

    Knowledge of the 3D magnetic filed structure at the time of major solar eruptions is vital to the understanding of the space weather effects of these eruptions. Multiple data-constrained techniques that reconstruct the 3D coronal field based on photospheric magnetograms have been used to achieve this goal. In particular, we have used the flux rope insertion method to obtain the coronal magnetic field of multiple regions containing flux ropes or sheared arcades based on line-of-sight magnetograms and X-ray and EUV observations of coronal loops. For the purpose of developing statistical measures of the goodness of fit of these models to the observations, here we present our modeling of flux ropes based on synthetic magnetograms obtained from aFan & Gibson emerging flux rope simulation. The goal is to study the effect of of different input flux rope parameters on the geometry of currents, field line connectivity, and topology, in a controled setting. For this purpose we create a large grid of models with the flux rope insertion method with different combinations of axial and poloidal flux, which give us different morphology of the flux rope. We create synthetic images of these flux ropes in AIA passbands with the FORWARD forward-fitting code. The present parametric study will later be used to get a better handle on the initial condition for magnetofrictional and MHD simulations of observed regions containing flux ropes, such as sigmoids and polar-crown filaments.

  13. Might axial myofascial properties and biomechanical mechanisms be relevant to ankylosing spondylitis and axial spondyloarthritis?

    PubMed

    Masi, Alfonse T

    2014-01-01

    Ankylosing spondylitis and axial spondyloarthropathy have characteristic age- and sex-specific onset patterns, typical entheseal lesions, and marked heritability, but the integrative mechanisms causing the pathophysiological and structural alterations remain largely undefined. Myofascial tissues are integrated in the body into webs and networks which permit transmission of passive and active tensional forces that provide stabilizing support and help to control movements. Axial myofascial hypertonicity was hypothesized as a potential excessive polymorphic trait which could contribute to chronic biomechanical overloading and exaggerated stresses at entheseal sites. Such a mechanism may help to integrate many of the characteristic host, pathological, and structural features of ankylosing spondylitis and axial spondyloarthritis. Biomechanical stress and strain were recently documented to correlate with peripheral entheseal inflammation and new bone formation in a murine model of spondyloarthritis. Ankylosing spondylitis has traditionally been classified by the modified New York criteria, which require the presence of definite radiographic sacroiliac joint lesions. New classification criteria for axial spondyloarthritis now include patients who do not fulfill the modified New York criteria. The male-to-female sex ratios clearly differed between the two patient categories - 2:1 or 3:1 in ankylosing spondylitis and 1:1 in non-radiographic axial spondyloarthritis - and this suggests a spectral concept of disease and, among females, milder structural alterations. Magnetic resonance imaging of active and chronic lesions in ankylosing spondylitis and axial spondyloarthritis reveals complex patterns, usually interpreted as inflammatory reactions, but shows similarities to acute degenerative disc disease, which attributed to edema formation following mechanical stresses and micro-damage. A basic question is whether mechanically induced microinjury and immunologically mediated

  14. Might axial myofascial properties and biomechanical mechanisms be relevant to ankylosing spondylitis and axial spondyloarthritis?

    PubMed Central

    2014-01-01

    Ankylosing spondylitis and axial spondyloarthropathy have characteristic age- and sex-specific onset patterns, typical entheseal lesions, and marked heritability, but the integrative mechanisms causing the pathophysiological and structural alterations remain largely undefined. Myofascial tissues are integrated in the body into webs and networks which permit transmission of passive and active tensional forces that provide stabilizing support and help to control movements. Axial myofascial hypertonicity was hypothesized as a potential excessive polymorphic trait which could contribute to chronic biomechanical overloading and exaggerated stresses at entheseal sites. Such a mechanism may help to integrate many of the characteristic host, pathological, and structural features of ankylosing spondylitis and axial spondyloarthritis. Biomechanical stress and strain were recently documented to correlate with peripheral entheseal inflammation and new bone formation in a murine model of spondyloarthritis. Ankylosing spondylitis has traditionally been classified by the modified New York criteria, which require the presence of definite radiographic sacroiliac joint lesions. New classification criteria for axial spondyloarthritis now include patients who do not fulfill the modified New York criteria. The male-to-female sex ratios clearly differed between the two patient categories - 2:1 or 3:1 in ankylosing spondylitis and 1:1 in non-radiographic axial spondyloarthritis - and this suggests a spectral concept of disease and, among females, milder structural alterations. Magnetic resonance imaging of active and chronic lesions in ankylosing spondylitis and axial spondyloarthritis reveals complex patterns, usually interpreted as inflammatory reactions, but shows similarities to acute degenerative disc disease, which attributed to edema formation following mechanical stresses and micro-damage. A basic question is whether mechanically induced microinjury and immunologically mediated

  15. Fe XII STALKS AND THE ORIGIN OF THE AXIAL FIELD IN FILAMENT CHANNELS

    SciTech Connect

    Wang, Y.-M.; Sheeley, N. R. Jr.; Stenborg, G. E-mail: neil.sheeley@nrl.navy.mil

    2013-06-10

    Employing Fe XII images and line-of-sight magnetograms, we deduce the direction of the axial field in high-latitude filament channels from the orientation of the adjacent stalklike structures. Throughout the rising phase of the current solar cycle 24, filament channels poleward of latitude 30 Degree-Sign overwhelmingly obeyed the hemispheric chirality rule, being dextral (sinistral) in the northern (southern) hemisphere, corresponding to negative (positive) helicity. During the deep minimum of 2007-2009, the orientation of the Fe XII stalks was often difficult to determine, but no obvious violations of the rule were found. Although the hemispheric trend was still present during the maximum and early declining phase of cycle 23 (2000-2003), several high-latitude exceptions were identified at that time. From the observation that dextral (sinistral) filament channels form through the decay of active regions whose Fe XII features show a counterclockwise (clockwise) whorl, we conclude that the axial field direction is determined by the intrinsic helicity of the active regions. In contrast, generation of the axial field component by the photospheric differential rotation is difficult to reconcile with the observed chirality of polar crown and circular filament channels, and with the presence of filament channels along the equator. The main role of differential rotation in filament channel formation is to expedite the cancellation of flux and thus the removal of the transverse field component. We propose further that, rather than being ejected into the heliosphere, the axial field is eventually resubmerged by flux cancellation as the adjacent unipolar regions become increasingly mixed.

  16. Parameter estimation and actuator characteristics of hybrid magnetic bearings for axial flow blood pump applications.

    PubMed

    Lim, Tau Meng; Cheng, Shanbao; Chua, Leok Poh

    2009-07-01

    Axial flow blood pumps are generally smaller as compared to centrifugal pumps. This is very beneficial because they can provide better anatomical fit in the chest cavity, as well as lower the risk of infection. This article discusses the design, levitated responses, and parameter estimation of the dynamic characteristics of a compact hybrid magnetic bearing (HMB) system for axial flow blood pump applications. The rotor/impeller of the pump is driven by a three-phase permanent magnet brushless and sensorless motor. It is levitated by two HMBs at both ends in five degree of freedom with proportional-integral-derivative controllers, among which four radial directions are actively controlled and one axial direction is passively controlled. The frequency domain parameter estimation technique with statistical analysis is adopted to validate the stiffness and damping coefficients of the HMB system. A specially designed test rig facilitated the estimation of the bearing's coefficients in air-in both the radial and axial directions. Experimental estimation showed that the dynamic characteristics of the HMB system are dominated by the frequency-dependent stiffness coefficients. By injecting a multifrequency excitation force signal onto the rotor through the HMBs, it is noticed in the experimental results the maximum displacement linear operating range is 20% of the static eccentricity with respect to the rotor and stator gap clearance. The actuator gain was also successfully calibrated and may potentially extend the parameter estimation technique developed in the study of identification and monitoring of the pump's dynamic properties under normal operating conditions with fluid. PMID:19566728

  17. Parameter estimation and actuator characteristics of hybrid magnetic bearings for axial flow blood pump applications.

    PubMed

    Lim, Tau Meng; Cheng, Shanbao; Chua, Leok Poh

    2009-07-01

    Axial flow blood pumps are generally smaller as compared to centrifugal pumps. This is very beneficial because they can provide better anatomical fit in the chest cavity, as well as lower the risk of infection. This article discusses the design, levitated responses, and parameter estimation of the dynamic characteristics of a compact hybrid magnetic bearing (HMB) system for axial flow blood pump applications. The rotor/impeller of the pump is driven by a three-phase permanent magnet brushless and sensorless motor. It is levitated by two HMBs at both ends in five degree of freedom with proportional-integral-derivative controllers, among which four radial directions are actively controlled and one axial direction is passively controlled. The frequency domain parameter estimation technique with statistical analysis is adopted to validate the stiffness and damping coefficients of the HMB system. A specially designed test rig facilitated the estimation of the bearing's coefficients in air-in both the radial and axial directions. Experimental estimation showed that the dynamic characteristics of the HMB system are dominated by the frequency-dependent stiffness coefficients. By injecting a multifrequency excitation force signal onto the rotor through the HMBs, it is noticed in the experimental results the maximum displacement linear operating range is 20% of the static eccentricity with respect to the rotor and stator gap clearance. The actuator gain was also successfully calibrated and may potentially extend the parameter estimation technique developed in the study of identification and monitoring of the pump's dynamic properties under normal operating conditions with fluid.

  18. Electrostatic mirror objective with eliminated spherical and axial chromatic aberrations.

    PubMed

    Bimurzaev, Seitkerim B; Serikbaeva, Gulnur S; Yakushev, Evgeniy M

    2003-01-01

    Computational formulae for the coefficients of the third-order spherical aberration and the second-order axial chromatic aberration are presented for an axially symmetric electrostatic electron mirror. A technique for eliminating the high-order derivatives of the potential axial distribution in mirror systems from the integrands is described. Conditions for elimination of spherical and axial chromatic aberrations, either separately or simultaneously, are found for a three-electrode axially symmetric mirror composed of coaxial cylinders of the same diameter. A principal scheme of the transmission electron microscope, where an electrostatic electron mirror serves as its objective, is presented. PMID:14599097

  19. Permanent GPS and crustal deformation in Greenland

    NASA Astrophysics Data System (ADS)

    Khan, S. A.

    2003-12-01

    The National Survey and Cadastre - Denmark (KMS) is responsible for the geodetic definition of the reference network in Greenland. Permanent GPS plays an important role in the monitoring and maintenance of the geodetic network. Furthermore, KMS supports the international GPS infrastructure and research by supporting IGS. In October 1998 KMS has established a permanent GPS station THU2 at Thule Airbase. Besides THU2 the old permanent station THU1 is also running. The Thule stations are important because they are two of the few northernmost stations in the IGS network. THU2 has been operating since March 1999, and it is now a high quality and high performance station contributing to the IGS Low-Earth Orbiters (LEO) network. Besides the GPS stations in Thule, KMS is also running a permanent GPS station SCOB in Scoresbysund, which was established in August 1997, and in October 2001 a permanent station QAQ1 was established in Qaqortoq. This station is registered at IGS. Furthermore, University of Colorado operates the IGS station Kellyville near Kangerlussuaq and a station in Kulusuk. Using the BERNESE software, we have calculated daily baseline solutions between the GPS sites. The time series of the 3D crustal movements are analyzed due to post glacial rebound, plate tectonic and seasonal deformations (e.g. atmosphere loading). In addition, we have used the GIPSY OASIS II software to obtain similar time series. The results are compared with modeled estimates of the glacial rebound.

  20. Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

    DOEpatents

    Koplow, Jeffrey P.

    2016-02-16

    Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.

  1. CFD Simulation of Casing Treatment of Axial Flow Compressors

    NASA Technical Reports Server (NTRS)

    DeWitt, Kenneth

    2005-01-01

    A computational study is carried out to understand the physical mechanism responsible for the improvement in stall margin of an axial flow rotor due to the circumferential casing grooves. It is shown that the computational tool used predicts an increase in operating range of the rotor when casing grooves are present. A budget of the axial momentum equation is carried out at the rotor casing in the tip gap in order to uncover the physical process behind this stall margin improvement. It is shown that for the smooth casing the net axial pressure force . However in the presence of casing grooves the net axial shear stress force acting at the casing is augmented by the axial force due to the radial transport of axial momentum, which occurs across the grooves and power stream interface. This additional force adds to the net axial viscous sheer force and thus leads to an increase in the stall margin of the rotor.

  2. 13 CFR 120.900 - Sources of permanent financing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Sources of permanent financing... Development Company Loan Program (504) Permanent Financing § 120.900 Sources of permanent financing. Permanent financing for each Project must come from three sources: the Borrower's contribution, Third-Party Loans,...

  3. Permanence and global attractivity for Lotka-Volterra difference systems.

    PubMed

    Lu, Z; Wang, W

    1999-09-01

    The permanence and global attractivity for two-species difference systems of Lotka-Volterra type are considered. It is proved that a cooperative system cannot be permanent. For a permanent competitive system, the explicit expression of the permanent set E is obtained and sufficient conditions are given to guarantee the global attractivity of the positive equilibrium of the system.

  4. 31 CFR 515.335 - Permanent resident alien.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States....

  5. 31 CFR 515.335 - Permanent resident alien.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States....

  6. 31 CFR 515.335 - Permanent resident alien.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States....

  7. 31 CFR 515.335 - Permanent resident alien.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States....

  8. 31 CFR 515.335 - Permanent resident alien.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States....

  9. Linear magnetic motor/generator. [to generate electric energy using magnetic flux for spacecraft power supply

    NASA Technical Reports Server (NTRS)

    Studer, P. A. (Inventor)

    1982-01-01

    A linear magnetic motor/generator is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator includes an axially movable actuator mechanism. A permament magnet mechanism defines a first magnetic flux path which passes through a first end portion of the actuator mechanism. Another permament magnet mechanism defines a second magnetic flux path which passes through a second end portion of the actuator mechanism. A drive coil defines a third magnetic flux path passing through a third central portion of the actuator mechanism. A drive coil selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux path.

  10. Flow Driven by an Archimedean Helical Permanent Magnetic Field. Part II: Transient and Modulated Flow Behaviors

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Wang, Xiaodong; Fautrelle, Yves; Etay, Jacqueline; Na, Xianzhao; Baltaretu, Florin

    2016-08-01

    The present study considers the transient and modulated flow behaviors of liquid metal driven by a helical permanent magnetic field. The transient process, in which the fluid at rest experiences an increase in the angular velocity, is observed both in secondary and global axial flow with duration time less than 1 second. The flow fields are measured quantitatively to reveal the evolution of the transient flow, and the transient process is due to the variation of the electromagnetic force. Besides, the modulated flow behaviors of global axial flow, which is significantly different from that of secondary flow, is expected to avoid flow-induced macrosegregation in solidification process if the modulated time is suitable because its direction reversed periodically with the modulated helical stirrer. In addition, an optimal modulation frequency, under which the magnetic field could efficiently stir the solute at the solidification front, exists both in secondary and global axial flow (0.1 Hz and 0.625 Hz, respectively). Future investigations will focus on additional metallic alloy solidification experiments.

  11. Flow field visualization about external axial corners

    NASA Technical Reports Server (NTRS)

    Talcott, N. A., Jr.

    1978-01-01

    An experimental investigation was conducted to visualize the flow field about external axial corners. The investigation was initiated to provide answers to questions about the inviscid flow pattern for continuing numerical investigations. Symmetrical and asymmetrical corner models were tested at a Reynolds number per meter of 60,700,000. Oil-flow and vapor-screen photographs were taken for both models at angle of attack and yaw. The paper presents the results of the investigation in the form of oil-flow photographs and the surrounding shock wave location obtained from the vapor screens.

  12. G-A and Octet Axial Charges

    SciTech Connect

    Huey-Wen Lin

    2009-12-01

    We review recent progress on lattice calculations of nucleon axial coupling constants, as well as couplings of other octet members. With a combined SU(3) fit to all octet baryons, we find a better determination of g_A = 1.18(4)_stat(6)_syst. Our predictions for g_SS = 0.450(21)_stat(27)_syst and g_XX = -0.277(15)_stat(19)_syst are better determined than previous theoretical estimations. Finally, we describe a preliminary first full-QCD calculation of semileptonic decay quantity (g1(0)= f1(0))S->n = -0.348(37).

  13. Water ingestion into jet engine axial compressors

    NASA Technical Reports Server (NTRS)

    Tsuchiya, T.; Murthy, S. N. B.

    1982-01-01

    An axial flow compressor has been tested with water droplet ingestion under a variety of conditions. The results illustrate the manner in which the compressor pressure ratio, efficiency and surging characteristics are affected. A model for estimating the performance of a compressor during water ingestion has been developed and the predictions obtained compare favorably with the test results. It is then shown that with respect to five droplet-associated nonlinearly-interacting processes (namely, droplet-blade interactions, blade performance changes, centrifugal action, heat and mass transfer processes and droplet break-up), the initial water content and centrifugal action play the most dominant roles.

  14. Digital enhancement of computerized axial tomograms

    NASA Technical Reports Server (NTRS)

    Roberts, E., Jr.

    1978-01-01

    A systematic evaluation was conducted of certain digital image enhancement techniques performed in image space. Three types of images were used, computer generated phantoms, tomograms of a synthetic phantom, and axial tomograms of human anatomy containing images of lesions, artificially introduced into the tomograms. Several types of smoothing, sharpening, and histogram modification were explored. It was concluded that the most useful enhancement techniques are a selective smoothing of singular picture elements, combined with contrast manipulation. The most useful tool in applying these techniques is the gray-scale histogram.

  15. Axial Tomography from Digitized Real Time Radiography

    DOE R&D Accomplishments Database

    Zolnay, A. S.; McDonald, W. M.; Doupont, P. A.; McKinney, R. L.; Lee, M. M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  16. Ultrasound velocities for axial eye length measurement.

    PubMed

    Hoffer, K J

    1994-09-01

    Since 1974, I have used individual sound velocities for each eye condition encountered for axial length measurement. The calculation results in 1,555 M/sec for the average phakic eye. A slower speed of 1,549 M/sec was found for an extremely long (30 mm) eye and a higher speed of 1,561 M/sec was noted for an extremely short (20 mm) eye. This inversely proportional velocity change can best be adjusted for by measuring the phakic eye at 1,532 M/sec and correcting the result by dividing the square of the measured axial length (AL1,532)2 by the difference of the measured axial length (AL1,532) minus 0.35 mm. A velocity of 1,534 M/sec was found for all aphakic eyes regardless of their length, and correction is clinically significant. The velocity of an eye containing a poly(methyl methacrylate) intraocular lens is not different from an average phakic eye but it does magnify the effect of axial length change. I recommend measuring the pseudophakic eye at 1,532 M/sec and adding to the result (AL1,532), + 0.04 + 44% of the IOL thickness. The speed for an eye with a silicone IOL was found to be 1,476 M/sec (or AL1,532 + 0.04 - 56% of IOL thickness) and for glass, 1,549 M/sec (or AL1,532 + 0.04 + 75% of IOL thickness). A speed of 1,139 M/sec was found for a phakic eye with silicone oil filling most of the vitreous cavity and 1,052 M/sec for an aphakic eye filled with oil. For varying volumes of oil, each eye should be calculated individually. The speed was 534 M/sec for phakic eyes filled with gas. Eyes containing a silicone IOL or oil or gas will create clinically significant errors (3 to 10 diopters) if the sound velocity is not corrected. PMID:7996413

  17. Shaped charge with an axial channel

    NASA Astrophysics Data System (ADS)

    Malygin, A. V.; Proskuryakov, E. V.; Sorokin, M. V.; Fomin, V. M.

    2011-05-01

    A shaped charge with an axial channel is considered. The charge is initiated by an impact of an annular plate. As a result, the shaped charge is initiated at all points of the domain shaped as a ring. The impact plate material and parameters (velocity, thickness, width, and distance covered by the plate) that ensure stable penetration of the shaped charge are determined. The results obtained can be used to develop a composite (e.g., "tandem") shaped charge of the "base-head" type (the charge located farther from the target is first initiated, followed by initiation of the charge located closer to the target).

  18. Flow visualization around axial flow fan blades

    NASA Astrophysics Data System (ADS)

    Kawaguchi, K.; Matsui, K.

    1986-02-01

    The flow around the blades of an axial flow fan was visualized by using a drum camera. The distribution of the flow velocity about the blades was determined by combining the spark tracing method with the smoke wire method, making it possible to determine the blade element efficiency. The efficiencies and noise levels of radiator cooling fans can be determined using this technique. The method was applied to two types of fans with different performances, and the flow around the wing was correlated with the wing tip efficiency. The effect of tip vortex on the total fan noise was quantified.

  19. Permanent isolation surface barrier: Functional performance

    SciTech Connect

    Wing, N.R.

    1993-10-01

    This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release.

  20. Electronic and optical properties of silicene under uni-axial and bi-axial mechanical strains: A first principle study

    NASA Astrophysics Data System (ADS)

    Mohan, Brij; Kumar, Ashok; Ahluwalia, P. K.

    2014-07-01

    The uni-axial and bi-axial mechanical strain mediated electronic band structures and dielectric properties of silicene have been investigated. It is found that on applying uni- and bi-axial strains, the band gap opens for smaller strain in silicene. However, on further increase of strain beyond 8% silicene changed into metal. The ultimate tensile strength estimated is 3.4 GPa. Imaginary part of dielectric function shows that the inter-band transitions are red-shifted for uni- and bi-axial tensile strains and are blue shifted for uni- and bi-axial compressive strains. Electron energy loss (EEL) function shows that the π+σ plasmon energies are red-shifted for uni- and bi-axial strains and blue-shifted for compressive strains. The π plasmons disappears for tensile and asymmetric strains. Bi-axial asymmetric strain is found to have no influence on inter-band transitions and π+σ plasmon energies.

  1. Patterns of Flux Emergence

    NASA Astrophysics Data System (ADS)

    Title, A.; Cheung, M.

    2008-05-01

    The high spatial resolution and high cadence of the Solar Optical Telescope on the JAXA Hinode spacecraft have allowed capturing many examples of magnetic flux emergence from the scale of granulation to active regions. The observed patterns of emergence are quite similar. Flux emerges as a array of small bipoles on scales from 1 to 5 arc seconds throughout the region that the flux eventually condenses. Because the fields emerging from the underlying flux rope my appear many in small segments and the total flux (absolute sum) is not a conserved quantity the amount of total flux on the surface may vary significantly during the emergence process. Numerical simulations of flux emergence exhibit patterns similar to observations. Movies of both observations and numerical simulations will be presented.

  2. Modified axial lead system in children.

    PubMed Central

    Macfarlane, P W; Coleman, E N; Simpson, A

    1977-01-01

    Preliminary studies have been made on the use of the modified axial lead system in infancy and childhood. A highly significant correlation between internipple distance and height suggested that internipple distance be used as an index for the selection of a template to facilitate placement of the chest electrodes (Z and X). A series of 4 triangular templates was designed. The use of a template one size too large or too small was shown not to lead to any significant error in waveform measurement. A further study showed that the reference level for the application of the praecordial electrodes should be the 5th intercostal space as for adults, but that no serious diagnostic error was likely to arise if the 4th or 6th intercostal space was chosen by mistake. A study of the Frank lead system suggested that the use of the 5th intercostal space as a reference level was more appropriate than the 4th intercostal space, which is generally adopted by users of that system. The conclusion reached was that the axial lead system is the preferred orthogonal lead system for children, with templates for 4 ranges of internipple distance (less than 10 cm; 15 to 20 cm; and less than 20 cm--adult build) being proposed to simplify electrode placement. Images PMID:911562

  3. The Supersonic Axial-Flow Compressor

    NASA Technical Reports Server (NTRS)

    Kantrowitz, Arthur

    1950-01-01

    An investigation has been made to explore the possibilities of axial-flow compressors operating with supersonic velocities into the blade rows. Preliminary calculations showed that very high pressure ratios across a stage, together with somewhat increased mass flows, were apparently possible with compressors which decelerated air through the speed of sound in their blading. The first phase of the investigation was the development of efficient supersonic diffusers to decelerate air through the speed of sound. The present report is largely a general discussion of some of the essential aerodynamics of single-stage supersonic axial-flow compressors. As an approach to the study of supersonic compressors, three possible velocity diagrams are discussed briefly. Because of the encouraging results of this study, an experimental single-stage supersonic compressor has been constructed and tested in Freon-12. In this compressor, air decelerates through the speed of sound in the rotor blading and enters the stators at subsonic speeds. A pressure ratio of about 1.8 at an efficiency of about 80 percent has been obtained.

  4. Late Pleistocene river migrations in response to thrust belt advance and sediment-flux steering - The Kura River (southern Caucasus)

    NASA Astrophysics Data System (ADS)

    von Suchodoletz, Hans; Gärtner, Andreas; Hoth, Silvan; Umlauft, Josefine; Sukhishvili, Lasha; Faust, Dominik

    2016-08-01

    One reaction of rivers toward allogenic triggers is the large-scale river channel migration in the form of avulsions or progressive lateral migrations (combing) that are widespread phenomena around the world during the late Quaternary. Because they potentially cause significant human and economic losses and significantly change geomorphic processes in the affected regions, a deeper knowledge about causes and rates is essential and furthermore helps to identify the dominant drivers of regional landscape evolution during different periods. One possible cause for river channel migrations is sediment-flux steering, i.e. the shift of rivers in sedimentary basins against a tectonically driven trend caused by transverse sediment discharge. During the last 30 years, sediment-flux steering has been investigated by field and experimental studies in extensional half-grabens with generally small-sized transverse catchments and/or volcaniclastic sedimentation. This study presents geomorphologic, geochronologic, and heavy mineral analyses together with complementary tectonomorphometric and earthquake data to investigate late Quaternary channel migrations of the Kura River in the southern foreland basin of the Greater Caucasus, a region where the late Quaternary landscape evolution is rather fragmentarily understood so far. Special emphasis of this study is given to the interplay between axial river flow and transverse sediment supply leading to sediment-flux steering. Large-scale migrations of the course of the Kura River during the late Quaternary reflect the interplay between tectonic processes leading to the southwestward advance of the Kura Fold-and-Thrust-Belt and climatically-triggered sediment-flux steering caused by aggradation phases of transverse rivers with comparatively large catchment areas in the Lesser Caucasus. During generally warmer periods such as the Holocene with fluvial incision and low sediment supply from the transverse rivers, the main Kura River could

  5. Realization of a permanent implantable pulsatile impeller heart with magnetically suspended motor.

    PubMed

    Qian, K X; Zheng, M

    1997-07-01

    A permanent impeller heart that could work for years was once an idea. However, now this idea is turning into reality through the use of the magnetically suspended motor. Recently, with our implantable pulsatile impeller pump, 3 left ventricular assisted calves survived for about 2 months (62, 54, and 46 days, respectively). The termination of the experiments was related to wear of the mechanical bearing, which resulted in vibration of the rotor and pump failure. All the experimental animals were in good condition prior to pump failure. It seemed as if the experiments could have lasted indefinitely if the bearing had not failed. All the hematological and biochemical data of the calves remained in normal or acceptable ranges; neither blood damage nor organ dysfunction of any animal was detected. During autopsy, no severe thrombus formation was found in the pump or vessels although a low dose of heparin (0.5-0.8 g/h) was given to increase the activated coagulation time (ACT) to 1.5-2.0 times its normal value. To solve the problem of bearing wear, a magnetically suspended motor was investigated and applied to the impeller pump. On the opposite sides of a disc connected to the rotor, 2 permanent magnet rings were embedded, one for driving and the other for axial suspension. Because both the driving and suspending coils with iron cores attract the disc, no radial bearing was needed. This newly devised impeller heart promises to have long-term and permanent applications. PMID:9212937

  6. Dovetail spoke internal permanent magnet machine

    DOEpatents

    Alexander, James Pellegrino; EL-Refaie, Ayman Mohamed Fawzi; Lokhandwalla, Murtuza; Shah, Manoj Ramprasad; VanDam, Jeremy Daniel

    2011-08-23

    An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque. The multiple pair of permanent magnets are disposed between the stacks. The rotor assembly also includes multiple middle wedges mounted between each pair of the multiple permanent magnets.

  7. Sexism and Permanent Exclusion from School

    ERIC Educational Resources Information Center

    Carlile, Anna

    2009-01-01

    Focussing on narratives collected during a two year participant observation research project in the children's services department of an urban local authority, this article addresses the intersection between incidents of permanent exclusion from school and assumptions made on the basis of a young person's gender. The article considers gendered…

  8. PROCEDURE FOR ESTIMATING PERMANENT TOTAL ENCLOSURE COSTS

    EPA Science Inventory

    The paper discusses a procedure for estimating permanent total enclosure (PTE) costs. (NOTE: Industries that use add-on control devices must adequately capture emissions before delivering them to the control device. One way to capture emissions is to use PTEs, enclosures that mee...

  9. Lowering the Permanent Rate of Unemployment.

    ERIC Educational Resources Information Center

    Feldstein, Martin S.

    The first section of the study on lowering the permanent rate of unemployment discusses the effects and limitations of increasing aggregate demand through fiscal and monetary policy and indicates the inability to achieve the desired level of unemployment simply by stimulating demand. Section 2 analyzes the characteristics and structure of our…

  10. [Pets as permanent excretors of zoonoses pathogens].

    PubMed

    Mayr, B

    1993-02-01

    When scrutinizing zoonoses with regard to risks for human beings, the spectrum of pathogens with dogs, cats and birds leading to persistent infections and consequently to the fact that the animals become carriers and permanent excretors is relatively small. Most of the zoonoses cause clinical symptoms and will be taken care of correspondingly. With regard to dogs there is a multitude of persistent infections that are transferred from the pet to the human being and vice versa. In reality, however, the importance of the dog as permanent excretor of zoonosis pathogens endangering human health is minimal, except for some parasitoses. As far as cats are concerned, the situation is totally different. Cats are carriers and permanent excretors of pasteurella, the pathogens of the so-called cat-scratch disease, trichophyton and microsporum species, toxoplasmosis and orthopox viruses. The new zoonosis feline pox serves as an example of the necessity of a permanent observation of persistently infected pets. Healthy, but persistently infected birds form a source of infection not to be underestimated. Through the beat of their wings they constantly stir up dried infectious excrements and dust and thus favour the airborn infection of human beings. Chlamydia psittaci, the Newcastle disease virus and Mycobacterium avium are of major importance in this context. The risk of transferring zoonosis pathogens from persistently infected pets to human beings can be minimized through prophylactic diagnosis, strict measures of hygiene, observation of the schedule of vaccinations for the respective species and regular use of anthelmintica.

  11. 27 CFR 18.38 - Permanent discontinuance.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Permanent discontinuance. 18.38 Section 18.38 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS PRODUCTION OF VOLATILE FRUIT-FLAVOR CONCENTRATE Qualification...

  12. 27 CFR 18.38 - Permanent discontinuance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Permanent discontinuance. 18.38 Section 18.38 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS PRODUCTION OF VOLATILE FRUIT-FLAVOR CONCENTRATE Qualification...

  13. Pupil Dilation and Object Permanence in Infants

    ERIC Educational Resources Information Center

    Sirois, Sylvain; Jackson, Iain R.

    2012-01-01

    This paper examines the relative merits of looking time and pupil diameter measures in the study of early cognitive abilities of infants. Ten-month-old infants took part in a modified version of the classic drawbridge experiment used to study object permanence (Baillargeon, Spelke, & Wasserman, 1985). The study involved a factorial design where…

  14. Considerations on the Development of Permanent Education.

    ERIC Educational Resources Information Center

    Ogunsbiye, Ayo

    This document presents possible ways in which Permanent Education in France could develop, based on experiments and research carried out at the Centre Universitaire de Cooperation Economique et Sociale (CUCES) and at the Institut National pour la Formation des Adults (INFA). Part one includes the following: the good to be had from continuing…

  15. PHELIX for flux compression studies

    SciTech Connect

    Turchi, Peter J; Rousculp, Christopher L; Reinovsky, Robert E; Reass, William A; Griego, Jeffrey R; Oro, David M; Merrill, Frank E

    2010-06-28

    PHELIX (Precision High Energy-density Liner Implosion eXperiment) is a concept for studying electromagnetic implosions using proton radiography. This approach requires a portable pulsed power and liner implosion apparatus that can be operated in conjunction with an 800 MeV proton beam at the Los Alamos Neutron Science Center. The high resolution (< 100 micron) provided by proton radiography combined with similar precision of liner implosions driven electromagnetically can permit close comparisons of multi-frame experimental data and numerical simulations within a single dynamic event. To achieve a portable implosion system for use at high energy-density in a proton laboratory area requires sub-megajoule energies applied to implosions only a few cms in radial and axial dimension. The associated inductance changes are therefore relatively modest, so a current step-up transformer arrangement is employed to avoid excessive loss to parasitic inductances that are relatively large for low-energy banks comprising only several capacitors and switches. We describe the design, construction and operation of the PHELIX system and discuss application to liner-driven, magnetic flux compression experiments. For the latter, the ability of strong magnetic fields to deflect the proton beam may offer a novel technique for measurement of field distributions near perturbed surfaces.

  16. Gas Flux and Density Surrounding a Cylindrical Aperture in the Free Molecular Flow Regime

    NASA Technical Reports Server (NTRS)

    Soulas, George C.

    2011-01-01

    The equations for rigorously calculating the particle flux and density surrounding a cylindrical aperture in the free molecular flow regime are developed and presented. The fundamental equations for particle flux and density from a reservoir and a diffusely reflecting surface will initially be developed. Assumptions will include a Maxwell-Boltzmann speed distribution, equal particle and wall temperatures, and a linear flux distribution along the cylindrical aperture walls. With this information, the equations for axial flux and density surrounding a cylindrical aperture will be developed. The cylindrical aperture will be divided into multiple volumes and regions to rigorously determine the surrounding axial flux and density, and appropriate limits of integration will be determined. The results of these equations will then be evaluated. The linear wall flux distribution assumption will be assessed. The axial flux and density surrounding a cylindrical aperture with a thickness-to-radius ratio of 1.25 will be presented. Finally, the equations determined in this study will be verified using multiple methods.

  17. Design and fabrication of direct-feedback gradiometer: Axial gradiometer made of superconductive films and SQUIDs

    NASA Astrophysics Data System (ADS)

    Yokosawa, Koichi; Kuriki, Shinya

    1994-12-01

    A new type of SQUID gradiometer, a direct-feedback gradiometer, is introduced in this paper. It is an axial gradiometer made of thin superconductive films. It consists of two magnetometers: a ``cancellation magnetometer'' and a ``sensing magnetometer.'' The feedback flux of the cancellation magnetometer is applied to both pickup coils of these magnetometers by connecting their feedback coils in a series. Environmental magnetic noise applied to the sensing magnetometer is cancelled by the magnetic flux measured by the cancellation magnetometer, when the two magnetometers are connected with normal conductive wires. The gradiometer has been fabricated and operated in a moderate magnetically shielded room. The capability to reduce environmental noise and thus to measure auditory evoked fields from the human brain has been confirmed.

  18. Improvement of the rotational characteristics in the HTSC-permanent magnet hybrid bearing using ring shaped magnet

    NASA Astrophysics Data System (ADS)

    Emoto, Kozo; Sugiyama, Ryo; Takagi, Shogo; Ohashi, Shunsuke

    2013-11-01

    We have developed the hybrid magnetic bearing using permanent magnets and the high-Tc bulk superconductor (HTSC). Pinning force of the HTSC is used for the levitation and the guidance. Repulsive force of the permanent magnets is introduced to increase the load weight of the magnetic bearing. In this system, the stator side permanent magnet has the ring type structure so that both pinning force and repulsive force are used effectively. In this paper, influence of the hybrid system on dynamic characteristics of the rotor is studied. The rotor which is supported by the hybrid magnetic bearing is rotated. Then, vibration and the gradient angle of the rotor are measured until the rotor reaches to the end of the resonance state. Three dimensional numerical analysis of the flux which penetrates on the surface of the HTSC is undertaken. The relation between the dynamic characteristics and the flux is considered, and that of the hybrid system is compared with the non-hybrid one. In the hybrid system, the flux is changed by the influences of the stator side permanent magnet. Vibration and the gradient angle of the hybrid system are shown to be smaller than that of the non-hybrid one.

  19. Magnetoresistive Flux Focusing Eddy Current Flaw Detection

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell A. (Inventor); Namkung, Min (Inventor); Simpson, John W. (Inventor)

    2005-01-01

    A giant magnetoresistive flux focusing eddy current device effectively detects deep flaws in thick multilayer conductive materials. The probe uses an excitation coil to induce eddy currents in conducting material perpendicularly oriented to the coil s longitudinal axis. A giant magnetoresistive (GMR) sensor, surrounded by the excitation coil, is used to detect generated fields. Between the excitation coil and GMR sensor is a highly permeable flux focusing lens which magnetically separates the GMR sensor and excitation coil and produces high flux density at the outer edge of the GMR sensor. The use of feedback inside the flux focusing lens enables complete cancellation of the leakage fields at the GMR sensor location and biasing of the GMR sensor to a location of high magnetic field sensitivity. In an alternate embodiment, a permanent magnet is positioned adjacent to the GMR sensor to accomplish the biasing. Experimental results have demonstrated identification of flaws up to 1 cm deep in aluminum alloy structures. To detect deep flaws about circular fasteners or inhomogeneities in thick multi-layer conductive materials, the device is mounted in a hand-held rotating probe assembly that is connected to a computer for system control, data acquisition, processing and storage.

  20. Magnetoresistive flux focusing eddy current flaw detection

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell A. (Inventor); Namkung, Min (Inventor); Simpson, John W. (Inventor)

    2005-01-01

    A giant magnetoresistive flux focusing eddy current device effectively detects deep flaws in thick multilayer conductive materials. The probe uses an excitation coil to induce eddy currents in conducting material perpendicularly oriented to the coil's longitudinal axis. A giant magnetoresistive (GMR) sensor, surrounded by the excitation coil, is used to detect generated fields. Between the excitation coil and GMR sensor is a highly permeable flux focusing lens which magnetically separates the GMR sensor and excitation coil and produces high flux density at the outer edge of the GMR sensor. The use of feedback inside the flux focusing lens enables complete cancellation of the leakage fields at the GMR sensor location and biasing of the GMR sensor to a location of high magnetic field sensitivity. In an alternate embodiment, a permanent magnet is positioned adjacent to the GMR sensor to accomplish the biasing. Experimental results have demonstrated identification of flaws up to 1 cm deep in aluminum alloy structures. To detect deep flaws about circular fasteners or inhomogeneities in thick multilayer conductive materials, the device is mounted in a hand-held rotating probe assembly that is connected to a computer for system control, data acquisition, processing and storage.

  1. Return flux experiment

    NASA Technical Reports Server (NTRS)

    Tveekrem, June L.

    1992-01-01

    All spacecraft emit molecules via outgassing, thruster plumes, vents, etc. The return flux is the portion of those molecules that scatter from the ambient atmosphere and return to the spacecraft. Return flux allows critical spacecraft surfaces to become contaminated even when there is no direct line of sight between the contamination source and the critical surface. Data from the Long Duration Exposure Facility (LDEF) show that contamination of LDEF surfaces could not have come entirely from direct flux. The data suggest significant return flux. Several computer models have been developed to simulate return flux, but the predictions have never been verified in orbit. Large uncertainties in predictions lead to overly conservative spacecraft designs. The purpose of the REturn FLux EXperiment (REFLEX) is to fly a controlled experiment that can be directly compared with predictions from several models.

  2. Return flux experiment

    NASA Astrophysics Data System (ADS)

    Tveekrem, June L.

    All spacecraft emit molecules via outgassing, thruster plumes, vents, etc. The return flux is the portion of those molecules that scatter from the ambient atmosphere and return to the spacecraft. Return flux allows critical spacecraft surfaces to become contaminated even when there is no direct line of sight between the contamination source and the critical surface. Data from the Long Duration Exposure Facility (LDEF) show that contamination of LDEF surfaces could not have come entirely from direct flux. The data suggest significant return flux. Several computer models have been developed to simulate return flux, but the predictions have never been verified in orbit. Large uncertainties in predictions lead to overly conservative spacecraft designs. The purpose of the REturn FLux EXperiment (REFLEX) is to fly a controlled experiment that can be directly compared with predictions from several models.

  3. Elastic Buckling of Orthotropic Plates Under Varying Axial Stresses

    NASA Technical Reports Server (NTRS)

    Badir, Ashraf; Hu, Hurang; Diallo, Abdouramane

    1997-01-01

    The elastic buckling load of simply supported rectangular orthotropic plates subjected to a second degree parabolic variation of axial stresses in the longitudinal direction is calculated using analytical methods. The variation of axial stresses is equilibrated by nonuniform shear stresses along the plate edges and transverse normal stresses. The influence of the aspect ratio is examined, and the results are compared with plates subjected to uniform axial stresses.

  4. First Simultaneous Views of the Axial and Lateral Perspectives of a Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Cabello, I.; Cremades, H.; Balmaceda, L.; Dohmen, I.

    2016-08-01

    The different appearances exhibited by coronal mass ejections (CMEs) are believed to be in part the result of different orientations of their main axis of symmetry, consistent with a flux-rope configuration. There are observational reports of CMEs seen along their main axis (axial perspective) and perpendicular to it (lateral perspective), but no simultaneous observations of both perspectives from the same CME have been reported to date. The stereoscopic views of the telescopes onboard the Solar-Terrestrial Relations Observatory (STEREO) twin spacecraft, in combination with the views from the Solar and Heliospheric Observatory (SOHO) and the Solar Dynamics Observatory (SDO), allow us to study the axial and lateral perspectives of a CME simultaneously for the first time. In addition, this study shows that the lateral angular extent ( L) increases linearly with time, while the angular extent of the axial perspective ( D) presents this behavior only from the low corona to {≈} 5 R_{⊙}, where it slows down. The ratio L/D ≈ 1.6 obtained here as the average over several points in time is consistent with measurements of L and D previously performed on events exhibiting only one of the perspectives from the single vantage point provided by SOHO.

  5. Heterogeneity of CH4 and net CO2 Fluxes Using Nested Chamber, Tower, Aircraft, Remote Sensing, and Modeling Approaches in Arctic Alaska for Regional Flux Estimation

    NASA Astrophysics Data System (ADS)

    Oechel, W. C.; Moreaux, V.; Kalhori, A. A. M.; Murphy, P.; Wilkman, E.; Sturtevant, C. S.; Zhuang, Q.; Miller, C. E.; Dinardo, S. J.; Fisher, J. B.; Gioli, B.; Zona, D.

    2014-12-01

    The topographic, environmental, biotic, and metabolic heterogeneity of terrestrial ecosystems and landscapes can be large even despite a seemingly homogeneous landscape. The error of estimating and simulating fluxes due to extant heterogeneity is commonly overlooked in regional and global estimates. Here we evaluate the pattern and controls on spatial heterogeneity on CH4 and CO2 fluxes over varying spatial scales. Data from the north slope of Alaska from chambers, up to a 16 year CO2 flux record from up to 7 permanent towers, over 20 portable tower locations, eddy covariance CH4 fluxes over several years and sites, new year-around CO2 and CH4 flux installations, hundreds of hours of aircraft concentration and fluxes, and terrestrial biosphere and flux inverse modeling, are used to evaluate the spatial variability of fluxes and to better estimate regional fluxes. Significant heterogeneity of fluxes is identified at varying scales from sub-meter scale to >100km. A careful consideration of the effect that heterogeneity causes when estimating ecosystem fluxes is critical to reliable regional and global estimates. The combination of eddy covariance tower flux, aircraft, remote sensing, and modeling can be used to provide reliable, accurate, regional assessments of CH4 and CO2 fluxes from large areas of heterogeneous landscape.

  6. Heat flux measurements

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Weikle, Donald H.

    1989-01-01

    A new automated, computer controlled heat flux measurement facility is described. Continuous transient and steady-state surface heat flux values varying from about 0.3 to 6 MW/sq m over a temperature range of 100 to 1200 K can be obtained in the facility. An application of this facility is the development of heat flux gauges for continuous fast transient surface heat flux measurement on turbine blades operating in space shuttle main engine turbopumps. The facility is useful for durability testing at fast temperature transients.

  7. Aspects of flux compactification

    NASA Astrophysics Data System (ADS)

    Liu, Tao

    In this thesis, we study three main aspects of flux compactifications: (1) classify supergravity solutions from flux compactification; (2) construct flux-deformed geometry and 4D low-energy theory to describe these flux vacua; and (3) study 4D particle phenomenology and cosmology of flux vacua. In the first part, we review G-structure, the basic tool to study supersymmetric flux solutions, and some typical solutions obtained in heterotic, type IIA and type IIB string theories. Then we present a comprehensive classification of supersymmetric vacua of M-theory compactification on 7D manifolds with general four-form fluxes. We analyze the cases where the resulting four-dimensional vacua have N = 1, 2, 3, 4 supersymmetry and the internal space allows for SU(2)-, SU(3)- or G 2-structures. In particular, we find for N = 2 supersymmetry, that the external space-time is Minkowski and the base manifold of the internal space is conformally Kahler for SU(2) structures, while for SU(3) structures the internal space has to be Einstein-Sasaki and no internal fluxes are allowed. Moreover, we provide a new vacuum with N = 1 supersymmetry and SU(3) structure, where all fluxes are non-zero and the first order differential equations are solved. In the second part, we simply review the methods used to construct one subclass of fluxed-deformed geometry or the so-called "twisted manifold", and the associated 4D effective theory describing these flux vacua. Then by employing (generalized) Scherk-Schwarz reduction, we construct the geometric twisting for Calabi-Yau manifolds of Voisin-Borcea type (K 3 x T2)/ Z2 and study the superpotential in a type IIA orientifold based on this geometry. The twists modify the direct product by fibering the K 3 over T2 while preserving the Z2 involution. As an important application, the Voisin-Borcea class contains T6/( Z2 x Z2 ), the usual setting for intersecting D6 brane model building. Past work in this context considered only those twists inherited

  8. Nuclear axial currents in chiral effective field theory

    DOE PAGES

    Baroni, Alessandro; Girlanda, Luca; Pastore, Saori; Schiavilla, Rocco; Viviani, Michele

    2016-01-11

    Two-nucleon axial charge and current operators are derived in chiral effective field theory up to one loop. The derivation is based on time-ordered perturbation theory and accounts for cancellations between the contributions of irreducible diagrams and the contributions owing to nonstatic corrections from energy denominators of reducible diagrams. Ultraviolet divergencies associated with the loop corrections are isolated in dimensional regularization. The resulting axial current is finite and conserved in the chiral limit, while the axial charge requires renormalization. As a result, a complete set of contact terms for the axial charge up to the relevant order in the power countingmore » is constructed.« less

  9. Modular functional organisation of the axial locomotor system in salamanders.

    PubMed

    Cabelguen, Jean-Marie; Charrier, Vanessa; Mathou, Alexia

    2014-02-01

    Most investigations on tetrapod locomotion have been concerned with limb movements. However, there is compelling evidence that the axial musculoskeletal system contributes to important functions during locomotion. Adult salamanders offer a remarkable opportunity to examine these functions because these amphibians use axial undulations to propel themselves in both aquatic and terrestrial environments. In this article, we review the currently available biological data on axial functions during various locomotor modes in salamanders. We also present data showing the modular organisation of the neural networks that generate axial synergies during locomotion. The functional implication of this modular organisation is discussed.

  10. Axial myopathy: an overlooked feature of muscle diseases.

    PubMed

    Witting, Nanna; Andersen, Linda K; Vissing, John

    2016-01-01

    Classically, myopathies are categorized according to limb or cranial nerve muscle affection, but with the growing use of magnetic resonance imaging it has become evident that many well-known myopathies have significant involvement of the axial musculature. New disease entities with selective axial muscle involvement have also been described recently, but overall the axial myopathy is unexplored. We performed a PubMed search using the search terms 'myopathy', 'paraspinal', 'axial' and 'erector'. Axial myopathy was defined as involvement of paraspinal musculature. We found evidence of axial musculature involvement in the majority of myopathies in which paraspinal musculature was examined. Even in diseases named after a certain pattern of non-axial muscle affection, such as facioscapulohumeral and limb girdle muscular dystrophies, affection of the axial musculature was often severe and early, compared to other muscle groups. Very sparse literature evaluating the validity of clinical assessment methods, electromyography, muscle biopsy and magnetic resonance imaging was identified and reference material is generally missing. This article provides an overview of the present knowledge on axial myopathy with the aim to increase awareness and spur interest among clinicians and researchers in the field.

  11. Aerodynamics of advanced axial-flow turbomachinery

    NASA Technical Reports Server (NTRS)

    Serovy, G. K.; Kavanagh, P.; Kiishi, T. H.

    1980-01-01

    A multi-task research program on aerodynamic problems in advanced axial-flow turbomachine configurations was carried out at Iowa State University. The elements of this program were intended to contribute directly to the improvement of compressor, fan, and turbine design methods. Experimental efforts in intra-passage flow pattern measurements, unsteady blade row interaction, and control of secondary flow are included, along with computational work on inviscid-viscous interaction blade passage flow techniques. This final report summarizes the results of this program and indicates directions which might be taken in following up these results in future work. In a separate task a study was made of existing turbomachinery research programs and facilities in universities located in the United States. Some potentially significant research topics are discussed which might be successfully attacked in the university atmosphere.

  12. Axial superresolution by synthetic aperture generation

    NASA Astrophysics Data System (ADS)

    Micó, V.; García, J.; Zalevsky, Z.

    2008-12-01

    The use of tilted illumination onto the input object in combination with time multiplexing is a useful technique to overcome the Abbe diffraction limit in imaging systems. It is based on the generation of an expanded synthetic aperture that improves the cutoff frequency (and thus the resolution limit) of the imaging system. In this paper we present an experimental validation of the fact that the generation of a synthetic aperture improves not only the lateral resolution but also the axial one. Thus, it is possible to achieve higher optical sectioning of three-dimensional (3D) objects than that defined by the theoretical resolution limit imposed by diffraction. Experimental results are provided for two different cases: a synthetic object (micrometer slide) imaged by a 0.14 numerical aperture (NA) microscope lens, and a biosample (swine sperm cells) imaged by a 0.42 NA objective.

  13. Axial and Radial Oxylipin Transport1[OPEN

    PubMed Central

    Gasperini, Debora; Chauvin, Adeline; Acosta, Ivan F.; Kurenda, Andrzej; Stolz, Stéphanie; Chételat, Aurore; Wolfender, Jean-Luc; Farmer, Edward E.

    2015-01-01

    Jasmonates are oxygenated lipids (oxylipins) that control defense gene expression in response to cell damage in plants. How mobile are these potent mediators within tissues? Exploiting a series of 13-lipoxygenase (13-lox) mutants in Arabidopsis (Arabidopsis thaliana) that displays impaired jasmonic acid (JA) synthesis in specific cell types and using JA-inducible reporters, we mapped the extent of the transport of endogenous jasmonates across the plant vegetative growth phase. In seedlings, we found that jasmonate (or JA precursors) could translocate axially from wounded shoots to unwounded roots in a LOX2-dependent manner. Grafting experiments with the wild type and JA-deficient mutants confirmed shoot-to-root oxylipin transport. Next, we used rosettes to investigate radial cell-to-cell transport of jasmonates. After finding that the LOX6 protein localized to xylem contact cells was not wound inducible, we used the lox234 triple mutant to genetically isolate LOX6 as the only JA precursor-producing LOX in the plant. When a leaf of this mutant was wounded, the JA reporter gene was expressed in distal leaves. Leaf sectioning showed that JA reporter expression extended from contact cells throughout the vascular bundle and into extravascular cells, revealing a radial movement of jasmonates. Our results add a crucial element to a growing picture of how the distal wound response is regulated in rosettes, showing that both axial (shoot-to-root) and radial (cell-to-cell) transport of oxylipins plays a major role in the wound response. The strategies developed herein provide unique tools with which to identify intercellular jasmonate transport routes. PMID:26338953

  14. Psychosocial factors and work related sickness absence among permanent and non-permanent employees

    PubMed Central

    Gimeno, D.; Benavides, F.; Amick, B.; Benach, J.; Martinez, J. M.

    2004-01-01

    Study objective: To examine the association between psychosocial work factors and work related sickness absence among permanent and non-permanent employees by sex. Design: A cross sectional survey conducted in 2000 of a representative sample of the European Union total active population, aged 15 years and older. The independent variables were psychological job demands and job control as measures of psychosocial work environment, and work related sickness absence as the main outcome. Poisson regression models were used to compute sickness absence days' rate ratios. Setting: 15 countries of the European Union. Participants: A sample of permanent (n = 12 875) and non-permanent (n = 1203) workers from the Third European Survey on Working Conditions. Results: High psychological job demands, low job control, and high strain and passive work were associated with higher work related sickness absence. The risks were more pronounced in non-permanent compared with permanent employees and men compared with women. Conclusions: This work extends previous research on employment contracts and sickness absence, suggesting different effects depending on psychosocial working conditions and sex. PMID:15365115

  15. A Novel Transverse Flux Machine for Vehicle Traction Applications

    SciTech Connect

    Wan, Zhao; Ahmed, Adeeb; Husain, Iqbal; Muljadi, Eduard

    2015-10-05

    A novel transverse flux machine topology for electric vehicle traction application using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to Halbach-array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from Finite Element Analysis (FEA) show the motor achieved comparable torque density to conventional rare-earth permanent magnet machines. This machine is a viable candidate for direct drive applications with low cost and high torque density.

  16. Novel Transverse Flux Machine for Vehicle Traction Applications: Preprint

    SciTech Connect

    Wan, Z.; Ahmed, A.; Husain, I.; Muljadi, E.

    2015-04-02

    A novel transverse flux machine topology for electric vehicle traction applications using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to the Halbach array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite-element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from finite element analysis (FEA) show that the motor achieved comparable torque density to conventional rare-earth permanent magnet (PM) machines. This machine is a viable candidate for direct-drive applications with low cost and high torque density.

  17. Video Meteor Fluxes

    NASA Technical Reports Server (NTRS)

    Campbell-Brown, M. D.; Braid, D.

    2011-01-01

    The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given set of observations, and to correct for observing biases and the sensitivity of the system. Previous measurements of sporadic fluxes are summarized in Figure 1; the values are given as a total number of meteoroids striking the earth in one year to a given limiting mass. The Gr n et al. (1985) flux model is included in the figure for reference. Fluxes for sporadic meteoroids impacting the Earth have been calculated for objects in the centimeter size range using Super-Schmidt observations (Hawkins & Upton, 1958); this study used about 300 meteors, and used only the physical area of overlap of the cameras at 90 km to calculate the flux, corrected for angular speed of meteors, since a large angular speed reduces the maximum brightness of the meteor on the film, and radiant elevation, which takes into account the geometric reduction in flux when the meteors are not perpendicular to the horizontal. They bring up corrections for both partial trails (which tends to increase the collecting area) and incomplete overlap at heights other than 90 km (which tends to decrease it) as effects that will affect the flux, but estimated that the two effects cancelled one another. Halliday et al. (1984) calculated the flux of meteorite-dropping fireballs with fragment masses greater than 50 g, over the physical area of sky accessible to the MORP fireball cameras, counting only observations in clear weather. In the micron size range, LDEF measurements of small craters on spacecraft have been used to

  18. Advanced axial field D.C. motor development for electric passenger vehicle

    NASA Technical Reports Server (NTRS)

    Jones, W. J.

    1982-01-01

    A wound-field axial-flux dc motor was developed for an electric vehicle drive system. The motor is essentially an axial-flux version of the classical Gramme-ring winding motor, but the active conductors are recessed into slots cut into the two opposite faces of the laminated tape-wound core ring. Three motors were built and tested in the program. The second (functional) model was a six-pole machine which weighed 88.5 kg. It developed 16.9 km (33.0 hp), and a max speed of 4800 rpm. Full load efficiency was 92% and predicted SAE D-cycle efficiency was 88%. The last engineering) model was a 4-pole machine with compoles, allowing a weight reduction to 45 kg (100 lbs.) while addressing some manufacturability problems. The engineering model was rated at 13.2 kw (17.6 hp) at 3000 rpm, with a peak power of 19.8 km (26.4 hp) and a max speed of 7200 rpm. Initial test results on this motor showed poor commutation and efficiency; the program was terminated without resolution of these problems.

  19. Advanced axial field D.C. motor development for electric passenger vehicle

    NASA Astrophysics Data System (ADS)

    Jones, W. J.

    1982-12-01

    A wound-field axial-flux dc motor was developed for an electric vehicle drive system. The motor is essentially an axial-flux version of the classical Gramme-ring winding motor, but the active conductors are recessed into slots cut into the two opposite faces of the laminated tape-wound core ring. Three motors were built and tested in the program. The second (functional) model was a six-pole machine which weighed 88.5 kg. It developed 16.9 km (33.0 hp), and a max speed of 4800 rpm. Full load efficiency was 92% and predicted SAE D-cycle efficiency was 88%. The last engineering) model was a 4-pole machine with compoles, allowing a weight reduction to 45 kg (100 lbs.) while addressing some manufacturability problems. The engineering model was rated at 13.2 kw (17.6 hp) at 3000 rpm, with a peak power of 19.8 km (26.4 hp) and a max speed of 7200 rpm. Initial test results on this motor showed poor commutation and efficiency; the program was terminated without resolution of these problems.

  20. Permanent genetic memory with >1 byte capacity

    PubMed Central

    Yang, Lei; Nielsen, Alec A.K.; Fernandez-Rodriguez, Jesus; McClune, Conor J.; Laub, Michael T.; Lu, Timothy K.; Voigt, Christopher A.

    2014-01-01

    Genetic memory enables the recording of information in the DNA of living cells. Memory can record a transient environmental signal or cell state that is then recalled at a later time. Permanent memory is implemented using irreversible recombinases that invert the orientation of a unit of DNA, corresponding to the [0,1] state of a bit. To expand the memory capacity, we have applied bioinformatics to identify 34 phage integrases (and their cognate attB and attP recognition sites), from which we build 11 memory switches that are perfectly orthogonal to each other and the FimE and HbiF bacterial invertases. Using these switches, a memory array is constructed in Escherichia coli that can record 1.375 bytes of information. It is demonstrated that the recombinases can be layered and used to permanently record the transient state of a transcriptional logic gate. PMID:25344638

  1. Towards Reliable Velocities of Permanent GNSS Stations

    NASA Astrophysics Data System (ADS)

    Bogusz, Janusz; Klos, Anna; Gruszczynska, Marta; Gruszczynski, Maciej

    2016-06-01

    In the modern geodesy the role of the permanent station is growing constantly. The proper treatment of the time series from such station lead to the determination of the reliable velocities. In this paper we focused on some pre-analysis as well as analysis issues, which have to be performed upon the time series of the North, East and Up components and showed the best, in our opinion, methods of determination of periodicities (by means of Singular Spectrum Analysis) and spatio-temporal correlations (Principal Component Analysis), that still exist in the time series despite modelling. Finally, the velocities of the selected European permanent stations with the associated errors determined following power-law assumption in the stochastic part is presented.

  2. The effect of axial and transverse loading on the transport properties of ITER Nb3Sn strands

    NASA Astrophysics Data System (ADS)

    Nijhuis, A.; Pompe van Meerdervoort, R. P.; Krooshoop, H. J. G.; Wessel, W. A. J.; Zhou, C.; Rolando, G.; Sanabria, C.; Lee, P. J.; Larbalestier, D. C.; Devred, A.; Vostner, A.; Mitchell, N.; Takahashi, Y.; Nabara, Y.; Boutboul, T.; Tronza, V.; Park, S.-H.; Yu, W.

    2013-08-01

    The differences in thermal contraction of the composite materials in a cable in conduit conductor (CICC) for the International Thermonuclear Experimental Reactor (ITER), in combination with electromagnetic charging, cause axial, transverse contact and bending strains in the Nb3Sn filaments. These local loads cause distributed strain alterations, reducing the superconducting transport properties. The sensitivity of ITER strands to different strain loads is experimentally explored with dedicated probes. The starting point of the characterization is measurement of the critical current under axial compressive and tensile strain, determining the strain sensitivity and the irreversibility limit corresponding to the initiation of cracks in the Nb3Sn filaments for axial strain. The influence of spatial periodic bending and contact load is evaluated by using a wavelength of 5 mm. The strand axial tensile stress-strain characteristic is measured for comparison of the axial stiffness of the strands. Cyclic loading is applied for transverse loads following the evolution of the critical current, n-value and deformation. This involves a component representing a permanent (plastic) change and as well as a factor revealing reversible (elastic) behavior as a function of the applied load. The experimental results enable discrimination in performance reduction per specific load type and per strand type, which is in general different for each manufacturer involved. Metallographic filament fracture studies are compared to electromagnetic and mechanical load test results. A detailed multifilament strand model is applied to analyze the quantitative impact of strain sensitivity, intrastrand resistances and filament crack density on the performance reduction of strands and full-size ITER CICCs. Although a full-size conductor test is used for qualification of a strand manufacturer, the results presented here are part of the ITER strand verification program. In this paper, we present an

  3. "Permanence" - An Adaptationist Solution to Fermi's Paradox?

    NASA Astrophysics Data System (ADS)

    Cirkovic, Milan M.

    A new solution of Fermi's paradox sketched by SF writer Karl Schroeder in his 2002. novel Permanence is investigated. It is argued that this solution is tightly connected with adaptationism - a widely discussed working hypothesis in evolutionary biology. Schroeder's hypothesis has important ramifications for astrobiology, SETI projects, and future studies. Its weaknesses should be explored without succumbing to the emotional reactions often accompanying adaptationist explanations.

  4. An overview of permanent and semipermanent fillers.

    PubMed

    Broder, Kevin W; Cohen, Steven R

    2006-09-01

    The demand for safe, effective, long-lasting, biocompatible dermal filler materials is increasing. Many products that include synthetic polymers and autologous tissue have emerged that attempt to meet these criteria. An overview of injectable permanent fillers, including ArteFill, Aquamid, and silicone, and semipermanent fillers, including Radiesse, Sculptra, and autologous fat, is presented. A discussion of their composition, histologic characteristics, antigenicity, U.S. Food and Drug Administration approval status, indications for use, efficacy, injection technique, and adverse effects is provided.

  5. Care of patients with permanent tracheostomy.

    PubMed

    Everitt, Erica

    The third article in our series on tracheostomy care discusses the care of patients with a permanent tracheostomy. While these patients make up a small proportion of all patients who have a tracheostomy inserted, they have complex needs. This means they require practitioners in both acute and community settings, who have time, support and competent tracheostomy-care skills, to achieve a successful discharge and ongoing management of their tracheostomy. PMID:27396099

  6. LCLS Spectral Flux Viewer

    2005-10-25

    This application (FluxViewer) is a tool for displaying spectral flux data for the Linac Coherent Light Source (LCLS). This tool allows the user to view sliced spatial and energy distributions of the photons selected for specific energies and positions transverse to the beam axis.

  7. Physical indicators of hydrologic permanence in forested headwater streams

    EPA Science Inventory

    Recent court cases have brought headwater streams and their hydrologic permanence into the forefront for regulatory agencies, so rapid field-based indicators of hydrologic permanence in streams are critically needed. Our study objectives were to 1) identify environmental charact...

  8. ARE SALAMANDERS USEFUL INDICATORS OF HYDROLOGIC PERMANENCE IN HEADWATER STREAMS?

    EPA Science Inventory

    Regulatory agencies need appropriate indicators of stream permanence to aid in jurisdictional determinations for headwater streams. We evaluated salamanders as permanence indicators because they are often abundant in fishless headwaters. Salamander and habitat data were collect...

  9. The Overheating Cause Analysis of Permanent Magnet Governor and Countermeasures

    NASA Astrophysics Data System (ADS)

    Hou, Xiang-Ni; Zhou, San-Ping; Wang, Yan-Jie

    2016-05-01

    The problem of overheating is the main factor to limit the serviceable range of permanent magnet governor, in order to find out the reason of overheating and its influencing factors, the numerical simulation of the cylindrical permanent magnet governor is carried out by using the computational fluid dynamics method. Results show that the internal high temperature fluid in the rotor of the Permanent magnet governor cannot flow is the main factor causing the overheating of the permanent magnet governor, opened air convection holes, and equipped with cooling fins in conductor rotor and permanent magnet rotor's outer circumference direction of the permanent magnet governor. The results of the study show that the internal air flow of the optimized permanent magnet governor is effective and the air flow rate is increased, the heat transfer effect is enhanced, the maximum temperature of the permanent magnet governor is decreased from 120.2 to 72.6, so the cooling effect is obvious.

  10. A Novel Integrated Structure with a Radial Displacement Sensor and a Permanent Magnet Biased Radial Magnetic Bearing

    PubMed Central

    Sun, Jinji; Zhang, Yin

    2014-01-01

    In this paper, a novel integrated structure is proposed in order to reduce the axial length of the high speed of a magnetically suspended motor (HSMSM) to ensure the maximum speed, which combines radial displacement sensor probes and the permanent magnet biased radial magnetic bearing in HSMSM. The sensor probes are integrated in the magnetic bearing, and the sensor preamplifiers are placed in the control system of the HSMSM, separate from the sensor probes. The proposed integrated structure can save space in HSMSMs, improve the working frequency, reduce the influence of temperature on the sensor circuit, and improve the stability of HSMSMs. PMID:24469351

  11. A novel integrated structure with a radial displacement sensor and a permanent magnet biased radial magnetic bearing.

    PubMed

    Sun, Jinji; Zhang, Yin

    2014-01-01

    In this paper, a novel integrated structure is proposed in order to reduce the axial length of the high speed of a magnetically suspended motor (HSMSM) to ensure the maximum speed, which combines radial displacement sensor probes and the permanent magnet biased radial magnetic bearing in HSMSM. The sensor probes are integrated in the magnetic bearing, and the sensor preamplifiers are placed in the control system of the HSMSM, separate from the sensor probes. The proposed integrated structure can save space in HSMSMs, improve the working frequency, reduce the influence of temperature on the sensor circuit, and improve the stability of HSMSMs. PMID:24469351

  12. A novel integrated structure with a radial displacement sensor and a permanent magnet biased radial magnetic bearing.

    PubMed

    Sun, Jinji; Zhang, Yin

    2014-01-24

    In this paper, a novel integrated structure is proposed in order to reduce the axial length of the high speed of a magnetically suspended motor (HSMSM) to ensure the maximum speed, which combines radial displacement sensor probes and the permanent magnet biased radial magnetic bearing in HSMSM. The sensor probes are integrated in the magnetic bearing, and the sensor preamplifiers are placed in the control system of the HSMSM, separate from the sensor probes. The proposed integrated structure can save space in HSMSMs, improve the working frequency, reduce the influence of temperature on the sensor circuit, and improve the stability of HSMSMs.

  13. AmeriFlux US-Tw1 Twitchell Wetland West Pond

    SciTech Connect

    Baldocchi, Dennis

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Tw1 Twitchell Wetland West Pond. Site Description - The Twitchell Wetland site is a 7.4-acre restored wetland on Twitchell Island, that is managed by the California Department of Water Resources (DWR) and the U.S. Geological Survey (USGS). In the fall of 1997, the site was permanently flooded to a depth of approximately 25 cm. The wetland was almost completely covered by cattails and tules by the third growing season. A flux tower equipped to analyze energy, H2O, CO2, and CH4 fluxes was installed on May 17, 2012.

  14. An Unbroken Axial-Vector Current Conservation Law

    NASA Astrophysics Data System (ADS)

    Sharafiddinov, Rasulkhozha S.

    2016-03-01

    The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space in which a neutrino is characterized by left as well as by right space-time coordinates. Therefore, it is not surprising that whatever the main purposes experiments about a quasielastic axial-vector mass say in favor of an axial-vector mirror Minkowski space-time.

  15. An Unbroken Axial-Vector Current Conservation Law

    NASA Astrophysics Data System (ADS)

    Sharafiddinov, Rasulkhozha S.

    2016-04-01

    The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space in which a neutrino is characterized by left as well as by right space-time coordinates. Therefore, it is not surprising that whatever the main purposes experiments about a quasielastic axial-vector mass say in favor of an axial-vector mirror Minkowski space-time.

  16. Through flow analysis within axial flow turbomachinery blade rows

    NASA Astrophysics Data System (ADS)

    Girigoswami, H.

    1986-09-01

    Using Katsanis' Through Flow Code, inviscid flow through an axial flow compressor rotor blade as well as flow through inlet guide vanes are analyzed and the computed parameters such as meridional velocity distribution, axial velocity distribution along radial lines, and velocity distribution over blade surfaces are presented.

  17. Study of a new airfoil used in reversible axial fans

    NASA Technical Reports Server (NTRS)

    Li, Chaojun; Wei, Baosuo; Gu, Chuangang

    1991-01-01

    The characteristics of the reverse ventilation of axial flow are analyzed. An s shaped airfoil with a double circular arc was tested in a wind tunnel. The experimental results showed that the characteristics of this new airfoil in reverse ventilation are the same as those in normal ventilation, and that this airfoil is better than the existing airfoils used on reversible axial fans.

  18. Axial viewing of an ICP with a graphite torch injector

    SciTech Connect

    Houk, R.L.; Winge, R.K.; Praphairaksit, N.

    1996-09-01

    A hollow graphite torch injector constricts the analyte emission zone and prevents the production of off-axis emission from the upstream reaches of the axial channel. These properties should both improve signal, reduce background and alleviate matrix effects during axial viewing of the ICP through a metal sampling orifice thrust into the plasma. Recent results along these lines will be presented.

  19. Superposition of nonparaxial vectorial complex-source spherically focused beams: Axial Poynting singularity and reverse propagation

    NASA Astrophysics Data System (ADS)

    Mitri, F. G.

    2016-08-01

    In this work, counterintuitive effects such as the generation of an axial (i.e., long the direction of wave motion) zero-energy flux density (i.e., axial Poynting singularity) and reverse (i.e., negative) propagation of nonparaxial quasi-Gaussian electromagnetic (EM) beams are examined. Generalized analytical expressions for the EM field's components of a coherent superposition of two high-order quasi-Gaussian vortex beams of opposite handedness and different amplitudes are derived based on the complex-source-point method, stemming from Maxwell's vector equations and the Lorenz gauge condition. The general solutions exhibiting unusual effects satisfy the Helmholtz and Maxwell's equations. The EM beam components are characterized by nonzero integer degree and order (n ,m ) , respectively, an arbitrary waist w0, a diffraction convergence length known as the Rayleigh range zR, and a weighting (real) factor 0 ≤α ≤1 that describes the transition of the beam from a purely vortex (α =0 ) to a nonvortex (α =1 ) type. An attractive feature for this superposition is the description of strongly focused (or strongly divergent) wave fields. Computations of the EM power density as well as the linear and angular momentum density fluxes illustrate the analysis with particular emphasis on the polarization states of the vector potentials forming the beams and the weight of the coherent beam superposition causing the transition from the vortex to the nonvortex type. Should some conditions determined by the polarization state of the vector potentials and the beam parameters be met, an axial zero-energy flux density is predicted in addition to a negative retrograde propagation effect. Moreover, rotation reversal of the angular momentum flux density with respect to the beam handedness is anticipated, suggesting the possible generation of negative (left-handed) torques. The results are particularly useful in applications involving the design of strongly focused optical laser

  20. 12 CFR 615.5206 - Permanent capital ratio computation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Capital Adequacy § 615.5206 Permanent capital ratio computation. (a) The institution's permanent capital ratio is determined on the basis of the... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Permanent capital ratio computation....

  1. 12 CFR 615.5205 - Minimum permanent capital standards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Capital Adequacy § 615.5205 Minimum permanent capital standards. Each institution shall at all times maintain permanent capital at a level of at... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Minimum permanent capital standards....

  2. 6 CFR 7.29 - Documents of permanent historical value.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 6 Domestic Security 1 2012-01-01 2012-01-01 false Documents of permanent historical value. 7.29... NATIONAL SECURITY INFORMATION Classified Information § 7.29 Documents of permanent historical value. The... contained in records determined to have permanent historical value under 44 U.S.C. 2107 before they...

  3. 6 CFR 7.29 - Documents of permanent historical value.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 6 Domestic Security 1 2014-01-01 2014-01-01 false Documents of permanent historical value. 7.29... NATIONAL SECURITY INFORMATION Classified Information § 7.29 Documents of permanent historical value. The... contained in records determined to have permanent historical value under 44 U.S.C. 2107 before they...

  4. 6 CFR 7.29 - Documents of permanent historical value.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 6 Domestic Security 1 2013-01-01 2013-01-01 false Documents of permanent historical value. 7.29... NATIONAL SECURITY INFORMATION Classified Information § 7.29 Documents of permanent historical value. The... contained in records determined to have permanent historical value under 44 U.S.C. 2107 before they...

  5. 6 CFR 7.29 - Documents of permanent historical value.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 6 Domestic Security 1 2011-01-01 2011-01-01 false Documents of permanent historical value. 7.29... NATIONAL SECURITY INFORMATION Classified Information § 7.29 Documents of permanent historical value. The... contained in records determined to have permanent historical value under 44 U.S.C. 2107 before they...

  6. 30 CFR 77.602 - Permanent splicing of trailing cables.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Permanent splicing of trailing cables. 77.602... COAL MINES Trailing Cables § 77.602 Permanent splicing of trailing cables. When permanent splices in trailing cables are made, they shall be: (a) Mechanically strong with adequate electrical conductivity;...

  7. 30 CFR 75.604 - Permanent splicing of trailing cables.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Permanent splicing of trailing cables. 75.604... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Trailing Cables § 75.604 Permanent splicing of trailing cables. When permanent splices in trailing cables are made, they shall be:...

  8. 8 CFR 1235.11 - Admission of conditional permanent residents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Admission of conditional permanent residents. (a) General—(1) Conditional residence based on family... unmarried minor child of an alien entrepreneur shall be admitted conditionally for a period of 2 years. At...) Expired conditional permanent resident status. The lawful permanent resident alien status of a...

  9. 13 CFR 120.900 - Sources of permanent financing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Sources of permanent financing. 120.900 Section 120.900 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Development Company Loan Program (504) Permanent Financing § 120.900 Sources of permanent financing....

  10. 77 FR 55895 - Permanent Closure of Cincinnati Blue Ash Airport

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... Federal Aviation Administration Permanent Closure of Cincinnati Blue Ash Airport AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of permanent closure of Cincinnati Blue Ash Airport (ISZ). SUMMARY: The... Cincinnati advising that on August 29, 2012, it was permanently closing Cincinnati Blue Ash Airport...

  11. Permanent magnet design for high-speed superconducting bearings

    DOEpatents

    Hull, John R.; Uherka, Kenneth L.; Abdoud, Robert G.

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing.

  12. Permanent magnet design for high-speed superconducting bearings

    DOEpatents

    Hull, J.R.; Uherka, K.L.; Abdoud, R.G.

    1996-09-10

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure is disclosed. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing. 9 figs.

  13. Condensed matter realization of the axial magnetic effect

    NASA Astrophysics Data System (ADS)

    Chernodub, Maxim N.; Cortijo, Alberto; Grushin, Adolfo G.; Landsteiner, Karl; Vozmediano, María A. H.

    2014-02-01

    The axial magneticeffect, i.e., the generation of an energy current parallel to an axial magnetic field coupling with opposite signs to left- and right-handed fermions, is a nondissipative transport phenomenon intimately related to the gravitational contribution to the axial anomaly. An axial magnetic field emerges naturally in condensed matter in so-called Weyl semimetals. We present a measurable implementation of the axial magnetic effect. We show that the edge states of a Weyl semimetal at finite temperature possess a temperature dependent angular momentum in the direction of the vector potential intrinsic to the system. Such a realization provides a plausible context for the experimental confirmation of the elusive gravitational anomaly.

  14. Off-center magnetic resonance imaging with permanent magnets

    NASA Astrophysics Data System (ADS)

    Abele, Manlio G.; Rusinek, Henry

    2008-04-01

    Magnets for magnetic resonance imaging are currently designed as structures that are symmetric with respect to the geometric center O of the magnet cavity. This symmetry results in a symmetric field configuration, where point O coincides with the imaging center S defined as the point where the field gradient is zero. However, in many clinical applications such as breast or spine imaging, the region of interest is displaced from the geometric center. We present a design method for yokeless permanent magnets, where the position of point S is dictated by the imaging requirements. The magnet is composed of uniformly magnetized triangular prisms and it does not require a ferromagnetic yoke to channel the magnetic flux. Given an arbitrary polygonal cavity, the design depends on the position of point F, where the magnetostatic potential is assumed to be equal to the magnetostatic potential of the external medium. For a long magnet, the position of the imaging center S coincides with point F. As an example of the off-center design, we analyze a three-dimensional yokeless magnet with cavity of width=length=80cm and height=45cm. The magnet generates a field above 0.5T when constructed using the NdFeB alloy of remanence larger than 1.3T. The off-center configuration offers flexibility in magnet design that makes it possible to focus on a particular region of the human body, without increasing magnet cavity, magnet size, or its weight

  15. Analysis of Vibration and Acoustic Noise in Permanent Magnet Motors.

    NASA Astrophysics Data System (ADS)

    Hwang, Sangmoon

    The drive motor is a frequent source of vibration and acoustic noise in many precision spindle motors. One of the electromagnetic sources of vibration in permanent magnet motors is the torque ripple, consisting of the reluctance torque and electromagnetic torque fluctuation. This type of vibration is becoming more serious with the advent of new high-grade magnets with increased flux density. Acoustic noise of electromagnetic origin is difficult to predict and its exact mechanism is unclear. The mechanism of noise generation should be revealed to design a quieter motor which is the modern customer's demand. For motor operation at low speeds and loads, torque ripple due to the reluctance torque is often a source of vibration and control difficulty. The reluctance torque in a motor was calculated from the flux density by a finite element method and the Maxwell stress method. Effects of design parameters, such as stator slot width, permanent slot width, airgap length and magnetization direction, were investigated. Magnet pole shaping, by gradually decreasing the magnet thickness toward edges, yields a sinusoidal shape of the reluctance torque with reduced harmonics, thus reducing the vibration. This dissertation also presents two motor design techniques: stator tooth notching and rotor pole skewing with magnet pole shaping, and the effect of each method on the output torque. The analysis shows that the reluctance torque can be nearly eliminated by the suggested designs, with minimal sacrifice of the output torque. In permanent magnet DC motors, the most popular design type is the trapezoidal back electro-motive force (BEMF), for switched DC controllers. It is demonstrated that the output torque profile of one phase energized is qualitatively equivalent to the BEMF profile for motors with reduced reluctance torque. It implies that design of BEMF profile is possible by magnetic modeling of a motor, without expensive and time-consuming experiments for different designs

  16. Investigation of a 7-pole/6-slot Halbach-magnetized permanent-magnet linear alternator used for free-piston stirling engines

    NASA Astrophysics Data System (ADS)

    Zheng, Ping; Tong, Chengde; Zhao, Jing; Yu, Bin; Li, Lin; Bai, Jingang; Zhang, Lu

    2012-04-01

    This paper investigates a 7-pole/6-slot Halbach-magnetized permanent-magnet linear alternator used for free piston Stirling engines (FPSEs). Taking the advantages of Halbach array, a 1 kW prototype alternator is designed. Considering the rms value of electromotive force (EMF) and harmonic distortion, the optimal length ratio of the axial- and radial-magnetized permanent magnets and thicknesses of the permanent magnets are optimized by 2D finite element method. The alternator detent force, which is an important factor for smooth operation of FPSEs, is studied by optimizing slot tip and end tooth. The load and thermal performances of the final design are simulated. A prototype alternator was designed, built and tested. Experimental data indicated satisfactory design.

  17. Critical Heat Flux Phenomena at HighPressure & Low Mass Fluxes: NEUP Final Report Part I: Experiments

    SciTech Connect

    Corradini, Michael; Wu, Qiao

    2015-04-30

    This report is a preliminary document presenting an overview of the Critical Heat Flux (CHF) phenomenon, the High Pressure Critical Heat Flux facility (HPCHF), preliminary CHF data acquired, and the future direction of the research. The HPCHF facility has been designed and built to study CHF at high pressure and low mass flux ranges in a rod bundle prototypical of conceptual Small Modular Reactor (SMR) designs. The rod bundle is comprised of four electrically heated rods in a 2x2 square rod bundle with a prototypic chopped-cosine axial power profile and equipped with thermocouples at various axial and circumferential positions embedded in each rod for CHF detection. Experimental test parameters for CHF detection range from pressures of ~80 – 160 bar, mass fluxes of ~400 – 1500 kg/m2s, and inlet water subcooling from ~30 – 70°C. The preliminary data base established will be further extended in the future along with comparisons to existing CHF correlations, models, etc. whose application ranges may be applicable to the conditions of SMRs.

  18. Intramolecular Nuclear Flux Densities

    NASA Astrophysics Data System (ADS)

    Barth, I.; Daniel, C.; Gindensperger, E.; Manz, J.; PéRez-Torres, J. F.; Schild, A.; Stemmle, C.; Sulzer, D.; Yang, Y.

    The topic of this survey article has seen a renaissance during the past couple of years. Here we present and extend the results for various phenomena which we have published from 2012-2014, with gratitude to our coauthors. The new phenomena include (a) the first reduced nuclear flux densities in vibrating diatomic molecules or ions which have been deduced from experimental pump-probe spectra; these "experimental" nuclear flux densities reveal several quantum effects including (b) the "quantum accordion", i.e., during the turn from bond stretch to bond compression, the diatomic system never stands still — instead, various parts of it with different bond lengths flow into opposite directions. (c) Wavepacket interferometry has been extended from nuclear densities to flux densities, again revealing new phenomena: For example, (d) a vibrating nuclear wave function with compact initial shape may split into two partial waves which run into opposite directions, thus causing interfering flux densities. (e) Tunneling in symmetric 1-dimensional double-well systems yields maximum values of the associated nuclear flux density just below the potential barrier; this is in marked contrast with negligible values of the nuclear density just below the barrier. (f) Nuclear flux densities of pseudorotating nuclei may induce huge magnetic fields. A common methodologic theme of all topics is the continuity equation which connects the time derivative of the nuclear density to the divergence of the flux density, subject to the proper boundary conditions. (g) Nearly identical nuclear densities with different boundary conditions may be related to entirely different flux densities, e.g., during tunneling in cyclic versus non-cyclic systems. The original continuity equation, density and flux density of all nuclei, or of all nuclear degrees of freedom, may be reduced to the corresponding quantities for just a single nucleus, or just a single degree of freedom.

  19. Vector and Axial Vector Pion Form Factors

    NASA Astrophysics Data System (ADS)

    Vitz, Michael; PEN Collaboration

    2015-04-01

    Radiative pion decay π+ -->e+ νγ (RPD) provides critical input to chiral perturbation theory (χPT). Aside from the uninteresting ``inner bremsstrahlung'' contribution from QED, the RPD rate contains ``structure dependent'' terms given by FV and FA, the vector and axial-vector pion form factors, respectively. The two appear in the decay rate in combinations FV -FA and FV +FA , i.e., in the so-called SD- and SD+ terms, respectively. The latter has been measured to high precision by the PIBETA collaboration. We report on the analysis of new data, measured by the PEN collaboration in runs between 2008 and 2010 at the Paul Scherrer Institute, Switzerland. We particularly focus on the possibility of improvement in the determination of the SD- term. Precise determinations of FV and FA test the validity of the CVC hypothesis, provide numerical input for the l9 +l10 terms in the χPT lagrangian, and constrain potential non-(V - A) terms, such as a possible tensor term FT. NSF grants PHY-0970013, 1307328, and others.

  20. Axial residual stresses in boron fibers

    NASA Technical Reports Server (NTRS)

    Behrendt, D. R.

    1978-01-01

    The axial residual stress distribution as a function of radius was determined from the fiber surface to the core including the average residual stress in the core. Such measurements on boron on tungsten (B/W) fibers show that the residual stresses for 102, 142, 203, and 366 micron diameter fibers were similar, being compressive at the surface and changing monotonically to a region of tensile within the boron. At approximately 25 percent of the original radius, the stress reaches a maximum tensile stress of about 860 mn/sq.m and then decreases to a compressive stress near the tungsten boride core. Data were presented for 203 micron diameter B/W fibers that show annealing above 900 C reduces the residual stresses. A comparison between 102 micron diameter B/W and boron on carbon (b/C) shows that the residual stresses were similar in the outer regions of the fibers, but that large differences near and in the core were observed. The effects of these residual stresses on the fracture of boron fibers were discussed.

  1. Axially localized states in Taylor Couette flows

    NASA Astrophysics Data System (ADS)

    Lopez, Jose M.; Marques, Francisco

    2014-11-01

    We present numerical simulations of the flow in a Taylor Couette system with the inner cylinder rotating and aspect ratio Γ restricted to 0 . 86 <Γ/N < 0 . 95 , being N the number of Taylor vortices. For these values a complex experimental bifurcation scenario has been reported. The transition from wavy vortex flow (WVF) to a very low frequency mode VLF happens via an axisymmetric eigenfunction. The VLF plays an essential role in the dynamics, leading to chaos through a two-tori period-doubling route. This chaotic regime vanishes with further increase in Re and gives rise to a new flow regime ALS characterized by the existence of large jet oscillations localized in some pairs of vortices. The aim of this numerical study is to extend the available information on ALS by means of a detailed exploration of the parameter space in which it occurs. Frequency analysis from time series simultaneously recorded at several points of the domain has been applied to identify the different transitions taking place. The VLF occurs in a wide range of control parameters and its interaction with the axially localized states is crucial is most transitions, either between different ALS or to the chaotic regime. Spanish Ministry of Education and Science Grants (with FEDER funds) FIS2013-40880 and BES-2010-041542.

  2. Computerized axial tomography in clinical pediatrics.

    PubMed

    McCullough, D C; Kufta, C; Axelbaum, S P; Schellinger, D

    1977-02-01

    Computerized axial tomography (CAT), a noninvasive radiologie method, provides a new dimension in screening and diagnosis of intracranial pathology. Evaluation of 725 scans in infants and children demonstrates that CAT may be performed with negligible risk, although sedation and restraint are essential to the successful performance of studies in children under 6 years of age. CAT is the preferred initial diagnostic method in suspected hydrocephalls and is accurate in the detection and precise localization of brain tumors. The management of hydrocephalus and brain tumors has been significantly altered by the availability of CAT. Few invasive neuroradiologic procedures are required and pneumography is especially curtailed. Serial scanning is the best available method of monitoring ventricular alterations in hydrocephalus, tumor size during radiotherapy or chemotherapy, and postoperative recurrence of benign neoplasms. Complex intracranial anomalies are detectable with computerized tomography, but complete definition of pathology often requires angiography and air studies. Limited clinical experience in detecting neonatal intraventricular hemorrhage suggests that CAT will be a valuable tool for futlre investigations of that problem.

  3. Axial compressor middle stage secondary flow study

    NASA Technical Reports Server (NTRS)

    Wagner, J. H.; Dring, R. P.; Joslyn, H. D.

    1983-01-01

    This report describes an experimental investigation of the secondary flow within and aft of an axial compressor model with thick endwall boundary layers. The objective of the study was to obtain detailed aerodynamic and trace gas concentration traverse data aft of a well documented isolated rotor for the ultimate purpose of improving the design phases of compressor development based on an improved physical understanding of secondary flow. It was determined from the flow visualization, aerodynamic, and trace gas concentration results that the relative unloading of the midspan region of the airfoil inhibitied a fullspan separation at high loading preventing the massive radial displacement of the hub corner stall to the tip. Radial distribution of high and low total pressure fluid influenced the magnitude of the spanwise distribution of loss, such that, there was a general decreases in loss near the hub to the extent that for the least loaded case a negative loss (increase in total pressure) was observed. The ability to determine the spanwise distribution of blockage was demonstrated. Large blockage was present in the endwall regions due to the corner stall and tip leakage with little blockage in the core flow region. Hub blockage was found to increase rapidly with loading.

  4. Hypothetical silicon nanotubes under axial compression

    NASA Astrophysics Data System (ADS)

    Kang, Jeong Won; Hwang, Ho Jung

    2003-03-01

    This study shows the response of silicon nanotubes (SiNTs) under axial compression using an atomistic simulation based on the Tersoff potential. The application of pressure, proportional to the deformation within Hook's law, eventually led to a collapse of the SiNT and an abrupt change in structure. Using the sum of the cross sections of the atoms on the SiNT cross section and the SiNT pressure, we determined Young's modulus for the SiNTs that was constant irrespective of the SiNTs' diameter. As the SiNTs' diameter increased, the collapse pressure, that is the critical stress, linearly decreased. However, the net forces on the SiNTs at their collapse were almost constant irrespective of the SiNTs' diameter. We calculated the variations in the unit cell volume as a function of pressure, which were not dealt with in previous works considering carbon nanotubes under compression. Using properly chosen parameters for the SiNTs (Young's modulus, effective spring constant, diameter, lattice constant and cylindrical volume modulus), the critical strain, the collapse pressure, the elastic energy and the critical volume at which the SiNT buckling occurs can be estimated by equations given in this work.

  5. Small axial turbine stator technology program

    NASA Technical Reports Server (NTRS)

    Brockett, W.; Kozak, A.

    1982-01-01

    An experimental investigation was conducted to determine the effects of surface finish, fillet radius, inlet boundary layer thickness, and free-stream inlet turbulence level on the aerodynamic performance of a small axial flow turbine stator. The principal objective of this program was to help understand why large turbine efficiency is not maintained when a large turbine is scaled to a smaller size. The stator used in this program as a one-sixth scale of a 762 mm (30 in.) diameter stator design with 50 vanes having a vane height of 17 mm (0.666 in.) and an aspect ratio of 1.77. A comprehensive overall test matrix was used to provide a complete engineering understanding of the effects of each variable over the full range of all the other variables. The range of each variable investigated was as follows: surface finish 0.1 micro (4 micro in.) to 2.4 micro (95 micro in.); boundary layer thickness 2 to 25 percent of channel height at each wall; fillet radius 0 mm (0 in.) to 1.0 mm (.040 in.) and turbulence 2 to 12 percent.

  6. High Power Co-Axial SRF Coupler

    SciTech Connect

    M.L. Neubauer, R.A. Rimmer

    2009-05-01

    There are over 35 coupler designs for SRF cavities ranging in frequency from 325 to 1500 MHz. Two-thirds of these designs are coaxial couplers using disk or cylindrical ceramics in various combinations and configurations. While it is well known that dielectric losses go down by several orders of magnitude at cryogenic temperatures, it not well known that the thermal conductivity also goes down, and it is the ratio of thermal conductivity to loss tangent (SRF ceramic Quality Factor) and ceramic volume which will determine the heat load of any given design. We describe a novel robust co-axial SRF coupler design which uses compressed window technology. This technology will allow the use of highly thermally conductive materials for cryogenic windows. The mechanical designs will fit into standard-sized ConFlat® flanges for ease of assembly. Two windows will be used in a coaxial line. The distance between the windows is adjusted to cancel their reflections so that the same window can be used in many different applications at various frequencies.

  7. A Longitudinal Mode Electromagnetic Acoustic Transducer (EMAT) Based on a Permanent Magnet Chain for Pipe Inspection.

    PubMed

    Cong, Ming; Wu, Xinjun; Qian, Chunqiao

    2016-01-01

    A new electromagnetic acoustic transducer (EMAT) design, employing a special structure of the permanent magnet chain, is proposed to generate and receive longitudinal guided waves for pipe inspection based on the magnetostriction mechanism. Firstly, a quantitative analysis of the excitation forces shows the influence of the radial component can be ignored. Furthermore, as the axial component of the static magnetic field is dominant, a method of solenoid testing coils connected in series is adopted to increase the signal amplitude. Then, two EMAT configurations are developed to generate and receive the L(0,2) guided wave mode. The experimental results show the circumferential notch can be identified and located successfully. Finally, a detailed investigation of the performance of the proposed EMATs is given. Compared to the conventional EMAT configuration, the proposed configurations have the advantages of small volume, light weight, easy installation and portability, which is helpful to improve inspection efficiency. PMID:27213400

  8. A Longitudinal Mode Electromagnetic Acoustic Transducer (EMAT) Based on a Permanent Magnet Chain for Pipe Inspection

    PubMed Central

    Cong, Ming; Wu, Xinjun; Qian, Chunqiao

    2016-01-01

    A new electromagnetic acoustic transducer (EMAT) design, employing a special structure of the permanent magnet chain, is proposed to generate and receive longitudinal guided waves for pipe inspection based on the magnetostriction mechanism. Firstly, a quantitative analysis of the excitation forces shows the influence of the radial component can be ignored. Furthermore, as the axial component of the static magnetic field is dominant, a method of solenoid testing coils connected in series is adopted to increase the signal amplitude. Then, two EMAT configurations are developed to generate and receive the L(0,2) guided wave mode. The experimental results show the circumferential notch can be identified and located successfully. Finally, a detailed investigation of the performance of the proposed EMATs is given. Compared to the conventional EMAT configuration, the proposed configurations have the advantages of small volume, light weight, easy installation and portability, which is helpful to improve inspection efficiency. PMID:27213400

  9. Design and analysis of permanent magnet moving coil type generator used in a micro-CHP generation system

    NASA Astrophysics Data System (ADS)

    Oros Pop, Susana Teodora; Berinde, Ioan; Vadan, Ioan

    2015-12-01

    This paper presents the design and analysis of a permanent magnet moving coil type generator driven by a free piston Stirling engine. This assemble free piston Stirling engine - permanent magnet moving coil type generator will be used in a combined heat and power (CHP) system for producing heat and power in residential area. The design procedure for moving coil type linear generator starts from the rated power imposed and finally uses the Faraday law of induction. The magneto-static magnetic field generated by permanent magnets is analyzed by means of Reluctance method and Finite Element Method in order to evaluate the magnetic flux density in the air gap, which is a design data imposed in the design stage, and the results are compared.

  10. Directed flux motor

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A directed flux motor described utilizes the directed magnetic flux of at least one magnet through ferrous material to drive different planetary gear sets to achieve capabilities in six actuated shafts that are grouped three to a side of the motor. The flux motor also utilizes an interwoven magnet configuration which reduces the overall size of the motor. The motor allows for simple changes to modify the torque to speed ratio of the gearing contained within the motor as well as simple configurations for any number of output shafts up to six. The changes allow for improved manufacturability and reliability within the design.

  11. Heat Flux Sensor

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A heat flux microsensor developed under a NASP Small Business Innovation Research (SBIR) has a wide range of potential commercial applications. Vatell Corporation originally designed microsensors for use in very high temperatures. The company then used the technology to develop heat flux sensors to measure the rate of heat energy flowing in and out of a surface as well as readings on the surface temperature. Additional major advantages include response to heat flux in less than 10 microseconds and the ability to withstand temperatures up to 1,200 degrees centigrade. Commercial applications are used in high speed aerodynamics, supersonic combustion, blade cooling, and mass flow measurements, etc.

  12. New Generalized D-State-Observers for Sensorless Drive of Permanent-Magnet Synchronous Motors

    NASA Astrophysics Data System (ADS)

    Shinnaka, Shinji

    This paper proposes new generalized D-state-observers as new minimum-order flux state-observers for sensorless drive of permanent-magnet synchronous motors. The proposed generalized D-state-observers, which are established by a new approach using filters in the D-module, contain the conventional D-state-observer as a special case, and the associated observer gain also contains the conventional one for the conventional D-state-observer as a special case. Consequently, The proposed generalized D-state-observers provide designers with higher degree of design flexibility. In addition, for the generalized D-state-observers, this paper presents a new analysis about estimation error of rotor flux fundamental component due to rotor flux harmonics originating from non-sinusoidal magnetization, which has been remaining as an unsolved problem so far. It is analytically shown and verified by numerical experiments that harmonics appear on the flux estimate in a similar manner to the original rotor flux harmonics from viewpoints of rotor phase error.

  13. Technological and economical analysis of salient pole and permanent magnet synchronous machines designed for wind turbines

    NASA Astrophysics Data System (ADS)

    Gündoğdu, Tayfun; Kömürgöz, Güven

    2012-08-01

    Chinese export restrictions already reduced the planning reliability for investments in permanent magnet wind turbines. Today the production of permanent magnets consumes the largest proportion of rare earth elements, with 40% of the rare earth-based magnets used for generators and other electrical machines. The cost and availability of NdFeB magnets will likely determine the production rate of permanent magnet generators. The high volatility of rare earth metals makes it very difficult to quote a price. Prices may also vary from supplier to supplier to an extent of up to 50% for the same size, shape and quantity with a minor difference in quality. The paper presents the analysis and the comparison of salient pole with field winding and of peripheral winding synchronous electrical machines, presenting important advantages. A neodymium alloy magnet rotor structure has been considered and compared to the salient rotor case. The Salient Pole Synchronous Machine and the Permanent Magnet Synchronous Machine were designed so that the plate values remain constant. The Eddy current effect on the windings is taken into account during the design, and the efficiency, output power and the air-gap flux density obtained after the simulation were compared. The analysis results clearly indicate that Salient Pole Synchronous Machine designs would be attractive to wind power companies. Furthermore, the importance of the design of electrical machines and the determination of criteria are emphasized. This paper will be a helpful resource in terms of examination and comparison of the basic structure and magnetic features of the Salient Pole Synchronous Machine and Permanent Magnet Synchronous Machine. Furthermore, an economic analysis of the designed machines was conducted.

  14. Online Fault Detection of Permanent Magnet Demagnetization for IPMSMs by Nonsingular Fast Terminal-Sliding-Mode Observer

    PubMed Central

    Zhao, Kai-Hui; Chen, Te-Fang; Zhang, Chang-Fan; He, Jing; Huang, Gang

    2014-01-01

    To prevent irreversible demagnetization of a permanent magnet (PM) for interior permanent magnet synchronous motors (IPMSMs) by flux-weakening control, a robust PM flux-linkage nonsingular fast terminal-sliding-mode observer (NFTSMO) is proposed to detect demagnetization faults. First, the IPMSM mathematical model of demagnetization is presented. Second, the construction of the NFTSMO to estimate PM demagnetization faults in IPMSM is described, and a proof of observer stability is given. The fault decision criteria and fault-processing method are also presented. Finally, the proposed scheme was simulated using MATLAB/Simulink and implemented on the RT-LAB platform. A number of robustness tests have been carried out. The scheme shows good performance in spite of speed fluctuations, torque ripples and the uncertainties of stator resistance. PMID:25490582

  15. Online fault detection of permanent magnet demagnetization for IPMSMs by nonsingular fast terminal-sliding-mode observer.

    PubMed

    Zhao, Kai-Hui; Chen, Te-Fang; Zhang, Chang-Fan; He, Jing; Huang, Gang

    2014-12-05

    To prevent irreversible demagnetization of a permanent magnet (PM) for interior permanent magnet synchronous motors (IPMSMs) by flux-weakening control, a robust PM flux-linkage nonsingular fast terminal-sliding-mode observer (NFTSMO) is proposed to detect demagnetization faults. First, the IPMSM mathematical model of demagnetization is presented. Second, the construction of the NFTSMO to estimate PM demagnetization faults in IPMSM is described, and a proof of observer stability is given. The fault decision criteria and fault-processing method are also presented. Finally, the proposed scheme was simulated using MATLAB/Simulink and implemented on the RT-LAB platform. A number of robustness tests have been carried out. The scheme shows good performance in spite of speed fluctuations, torque ripples and the uncertainties of stator resistance.

  16. Prediction of iron losses in doubly salient permanent magnet machine with rectangular current waveform

    NASA Astrophysics Data System (ADS)

    Zhang, Jianzhong; Wang, Minxi; Cheng, Ming

    2012-04-01

    Iron losses in doubly salient permanent magnet (DSPM) machine are difficult to predict, as the flux waveforms are complex and dc bias existed. This paper measures iron losses at no load for different rotor speeds and these measured loss data are used to calibrate the iron loss model of the DSPM machine. Then the iron losses at rated load are predicted under three phase rectangular currents exerting on the armature windings. The result shows that small increment of iron losses is in the rotor at rated load which do benefit to the rotor thermal dissipation design.

  17. Permanent ground anchors: Nicholson design criteria

    NASA Astrophysics Data System (ADS)

    Nicholson, P. J.; Uranowski, D. D.; Wycliffe-Jones, P. T.

    1982-09-01

    The methods used by Nicholson Construction Company in the design of permanent ground anchors specifically as related to retaining walls are discussed. Basic soil parameters, design concepts, drilling and grouting methods for ground anchors are discussed. Particular emphasis is placed on anchors founded in soil rather than rock formations. Also, soil properties necessary for the proper design of anchored retaining walls are detailed. The second chapter of the report is devoted to a general discussion of retaining wall and anchor design. In addition, a design example of an anchored retaining wall is presented in a step by step manner.

  18. Gating of Permanent Molds for Aluminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    This report summarizes a two-year project, DE-FC07-011D13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was to determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings. Equipment and procedure for real time X-Ray radiography of molten aluminum flow into permanent molds have been developed. Other studies have been conducted using water flow and behavior of liquid aluminum in sand mold using real time photography. This investigation utilizes graphite molds transparent to X-Rays making it possible to observe the flow pattern through a number of vertically oriented grating systems. These have included systems that are choked at the base of a rounded vertical sprue and vertical gating systems with a variety of different ingates into the bottom of a mold cavity. These systems have also been changed to include gating systems with vertical and horizontal gate configurations. Several conclusions can be derived from this study. A sprue-well, as designed in these experiments, does not eliminate the vena contracta. Because of the swirling at the sprue-base, the circulating metal begins to push the entering metal stream toward the open runner mitigating the intended effect of the sprue-well. Improved designs of

  19. [THE VITAL PULP THERAPY IN PERMANENT TEETH].

    PubMed

    Makowiecki, Piotr; Trusewicz, Matylda; Tyszler, Lukasz; Buczkowska-Radlińska, Jadwiga

    2014-01-01

    The vitality of dental pulp is essential for long-term tooth survival. The aim of vital pulp therapy is to preserve vital, healthy pulp tissue. This therapy's foundation is the elimination of bacteria from the dentin-pulp complex. The treatment option depends on the cause and extent of mineralised tooth tissue destruction. The outcome of such treatment is determined by accurate assessment of the pulp's status and the dentist's ability to predict the success of the therapy. The aim of this review is to facilitate the dentist in making a proper decision referring to vital pulp therapy in permanent teeth, and to provide an overview of new approaches in such treatment.

  20. Permanent-magnet-less synchronous reluctance system

    DOEpatents

    Hsu, John S

    2012-09-11

    A permanent magnet-less synchronous system includes a stator that generates a magnetic revolving field when sourced by an alternating current. An uncluttered rotor is disposed within the magnetic revolving field and spaced apart from the stator to form an air gap relative to an axis of rotation. The rotor includes a plurality of rotor pole stacks having an inner periphery biased by single polarity of a north-pole field and a south-pole field, respectively. The outer periphery of each of the rotor pole stacks are biased by an alternating polarity.

  1. Permanent tooth sizes in 46,XY females.

    PubMed Central

    Alvesalo, L; Varrela, J

    1980-01-01

    The teeth of seven Finnish patients with complete testicular-feminization syndrome (46,XY females) were studied to obtain further information about their growth and possible somatic determinants on the Y chromosome. The sizes of the permanent teeth of the 46,XY females were found to be as large as those of control males and definitely larger than those of control females. Testicular feminization is caused by androgen insensitivity, and persons affected are phenotypically females. Hence, these results also indicate the influence of the Y chromosome on dental determination. PMID:7424913

  2. Batch fabrication of precision miniature permanent magnets

    DOEpatents

    Christenson, Todd R.; Garino, Terry J.; Venturini, Eugene L.

    2002-01-01

    A new class of processes for fabrication of precision miniature rare earth permanent magnets is disclosed. Such magnets typically have sizes in the range 0.1 to 10 millimeters, and dimensional tolerances as small as one micron. Very large magnetic fields can be produced by such magnets, lending to their potential application in MEMS and related electromechanical applications, and in miniature millimeter-wave vacuum tubes. This abstract contains simplifications, and is supplied only for purposes of searching, not to limit or alter the scope or meaning of any claims herein.

  3. Cutaneous complications related to permanent decorative tattooing.

    PubMed

    Kluger, Nicolas

    2010-05-01

    Decorative tattooing involves the introduction of exogenous pigments and/or dyes into the dermis to produce a permanent design. Practiced for thousands of years, it has gained tremendous popularity during the past 20 years, especially among the young. Tattoo-associated cutaneous complications have only been reported since the end of the 19th Century. With the increased prevalence of tattooed individuals, dermatologists have witnessed increasing numbers of patients presenting with complaints about their tattoos. Complications primarily include infections, hypersensitivity reaction to tattoo pigments, benign and sometimes malignant tumors arising on tattoos, and the localization of various dermatoses to tattoos. PMID:20441423

  4. Advances in nanostructured permanent magnets research

    SciTech Connect

    Poudyal, N; Liu, JP

    2012-12-14

    This paper reviews recent developments in research in nanostructured permanent magnets ( hard magnetic materials) with emphasis on bottom-up approaches to fabrication of hard/soft nanocomposite bulk magnets. Theoretical and experimental findings on the effects of soft phase and interface conditions on interphase exchange interactions are given. Synthesis techniques for hard magnetic nanoparticles, including chemical solution methods, surfactant-assisted ball milling and other physical deposition methods are reviewed. Processing and magnetic properties of warm compacted and plastically deformed bulk magnets with nanocrystalline morphology are discussed. Prospects of producing bulk anisotropic hard/soft nanocomposite magnets are presented.

  5. An overview of permanent and semipermanent fillers.

    PubMed

    Broder, Kevin W; Cohen, Steven R

    2006-09-01

    The demand for safe, effective, long-lasting, biocompatible dermal filler materials is increasing. Many products that include synthetic polymers and autologous tissue have emerged that attempt to meet these criteria. An overview of injectable permanent fillers, including ArteFill, Aquamid, and silicone, and semipermanent fillers, including Radiesse, Sculptra, and autologous fat, is presented. A discussion of their composition, histologic characteristics, antigenicity, U.S. Food and Drug Administration approval status, indications for use, efficacy, injection technique, and adverse effects is provided. PMID:16936539

  6. Strong permanent magnet-assisted electromagnetic undulator

    DOEpatents

    Halbach, Klaus

    1988-01-01

    This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles.

  7. Perlite for permanent confinement of cesium

    NASA Astrophysics Data System (ADS)

    Balencie, J.; Burger, D.; Rehspringer, J.-L.; Estournès, C.; Vilminot, S.; Richard-Plouet, M.; Boos, A.

    2006-06-01

    We present the potential use of expanded perlite, a metastable amorphous hydrated aluminium silicate, as a permanent medium for the long-term confinement of cesium. The method requires simply a loading by mixing an aqueous cesium nitrate solution and expanded perlite at 300 K followed by densification by sintering. The formation of pollucite, CsAlSi2O6, a naturally occurring mineral phase, upon careful heat treatment is demonstrated by X-ray diffraction. Leaching tests on the resulting glass-ceramics reveal a very low Cs departure of 0.5 mg m-2 d-1.

  8. In-core flux sensor evaluations at the ATR critical facility

    SciTech Connect

    Troy Unruh; Benjamin Chase; Joy Rempe; David Nigg; George Imel; Jason Harris; Todd Sherman; Jean-Francois Villard

    2014-09-01

    Flux detector evaluations were completed as part of a joint Idaho State University (ISU) / Idaho National Laboratory (INL) / French Atomic Energy commission (CEA) ATR National Scientific User Facility (ATR NSUF) project to compare the accuracy, response time, and long duration performance of several flux detectors. Special fixturing developed by INL allows real-time flux detectors to be inserted into various ATRC core positions and perform lobe power measurements, axial flux profile measurements, and detector cross-calibrations. Detectors initially evaluated in this program include the French Atomic Energy Commission (CEA)-developed miniature fission chambers; specialized self-powered neutron detectors (SPNDs) developed by the Argentinean National Energy Commission (CNEA); specially developed commercial SPNDs from Argonne National Laboratory. As shown in this article, data obtained from this program provides important insights related to flux detector accuracy and resolution for subsequent ATR and CEA experiments and flux data required for bench-marking models in the ATR V&V Upgrade Initiative.

  9. Conservative axial burnup distributions for actinide-only burnup credit

    SciTech Connect

    Kang, C.; Lancaster, D.

    1997-11-01

    Unlike the fresh fuel approach, which assumes the initial isotopic compositions for criticality analyses, any burnup credit methodology must address the proper treatment of axial burnup distributions. A straightforward way of treating a given axial burnup distribution is to segment the fuel assembly into multiple meshes and to model each burnup mesh with the corresponding isotopic compositions. Although this approach represents a significant increase in modeling efforts compared to the uniform average burnup approach, it can adequately determine the reactivity effect of the axial burnup distribution. A major consideration is what axial burnup distributions are appropriate for use in light of many possible distributions depending on core operating conditions and histories. This paper summarizes criticality analyses performed to determine conservative axial burnup distributions. The conservative axial burnup distributions presented in this paper are included in the Topical Report on Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel Packages, Revision 1 submitted in May 1997 by the US Department of Energy (DOE) to the US Nuclear Regulatory Commission (NRC). When approved by NRC, the conservative axial burnup distributions may be used to model PWR spent nuclear fuel for the purpose of gaining actinide only burnup credit.

  10. Axial transport of bidisperse granular mixtures in a rotating drum

    NASA Astrophysics Data System (ADS)

    Khan, Zeina

    2005-03-01

    Bidisperse granular mixtures rapidly size segregate when tumbled in a partially filled, horizontal drum. The smaller component moves radially toward the axis of rotation and forms a buried core. On a longer time scale, axial modulations of the core may develop and grow into a series of bands along the drum, which become visible upon breaking the surface. Using a narrow pulse of the smaller component as the intitial condition, we observe that the axial transport of the radial core is a subdiffusive front advancement process. The front motion is subdiffusive in the sense that the radially integrated concentration forms a self-similar, compact axial pulse whose width grows as t^α, with α˜1/3 < 1/2, and hence it spreads much more slowly than by diffusion in a mixture which does not exhibit axial banding. By coloring some of the larger grains, we find that the mixing and axial transport of the larger grains is similarly subdiffusive. We report on the effects of changing relative grain size and drum diameter on the axial transport of grains. We find that mixing occurs in the radial core, and axial band formation is enhaced in these cases.

  11. Large scale, regional, CH4 and net CO2 fluxes using nested chamber, tower, aircraft flux, remote sensing, and modeling approaches in Arctic Alaska

    NASA Astrophysics Data System (ADS)

    Oechel, Walter; Moreaux, Virginie; Kalhori, Aram; Losacco, Salvatore; Murphy, Patrick; Wilkman, Eric; Zona, Donatella

    2014-05-01

    The topographic, environmental, biotic, and metabolic heterogeneity of terrestrial ecosystems and landscapes can be large even despite a seemingly homogeneous landscape. The error of estimating and simulating fluxes due to extant heterogeneity is commonly overlooked in regional and global estimates. We evaluate the pattern and controls on spatial heterogeneity on GHG fluxes over varying spatial scales and compare to standard estimates of NEE and other greenhouse gas fluxes. Data from the north slope of Alaska from up to a 16 year flux record from up to 7 permanent towers, over 20 portable tower locations, and hundreds of hours of aircraft fluxes, are used to evaluate the spatial variability of fluxes and to better estimate regional fluxes. Significant heterogeneity of fluxes is identified at varying scales from sub-meter scale to >100km. A careful consideration of the effect that heterogeneity causes when estimating ecosystem fluxes is critical to reliable regional and global estimates. The combination of tower, flux aircraft, remote sensing, and modeling can be used to provide reliable, accurate, regional assessments of CH4and CO2 fluxes or large areas of heterogeneous landscape.

  12. Modeling Magnetic Flux Ropes

    NASA Astrophysics Data System (ADS)

    Xia, Chun; Keppens, Rony

    2014-01-01

    The magnetic configuration hosting prominences can be a large-scale helical magnetic flux rope. As a necessary step towards future prominence formation studies, we report on a stepwise approach to study flux rope formation. We start with summarizing our recent three-dimensional (3D) isothermal magnetohydrodynamic (MHD) simulation where a flux rope is formed, including gas pressure and gravity. This starts from a static corona with a linear force-free bipolar magnetic field, altered by lower boundary vortex flows around the main polarities and converging flows towards the polarity inversion. The latter flows induce magnetic reconnection and this forms successive new helical loops so that a complete flux rope grows and ascends. After stopping the driving flows, the system relaxes to a stable helical magnetic flux rope configuration embedded in an overlying arcade. Starting from this relaxed isothermal endstate, we next perform a thermodynamic MHD simulation with a chromospheric layer inserted at the bottom. As a result of a properly parametrized coronal heating, and due to radiative cooling and anisotropic thermal conduction, the system further relaxes to an equilibrium where the flux rope and the arcade develop a fully realistic thermal structure. This paves the way to future simulations for 3D prominence formation.

  13. High Power Co-Axial Coupler

    SciTech Connect

    Johnson, Rolland; Neubauer, Michael

    2013-08-14

    A superconducting RF (SRF) power coupler capable of handling 500 kW CW RF power at 750 MHz is required for present and future storage rings and linacs. There are over 35 coupler designs for SRF cavities ranging in frequency from 325 to 1500 MHz. Coupler windows vary from cylinders to cones to disks and RF power couplers will always be limited by the ability of ceramic windows and their matching systems to withstand the stresses due to non-uniform heating from dielectric and wall losses, multipactor, and mechanical flexure. In the Phase II project, we built a double window coaxial system with materials that would not otherwise be useable due to individual VSWRs. Double window systems can be operated such that one is cold (LN2) and one is warm. They can have different materials and still have a good match without using matching elements that create problematic multipactor bands. The match of the two windows will always result from the cancellation of the two window’s reflections when they are located approximately a quarter wavelength apart or multiples of a quarter wavelength. The window assemblies were carefully constructed to put the window material and its braze joint in compression at all times. This was done using explosion bonding techniques which allow for inexpensive fabrication of the vacuum / compression ring out of stainless steel with copper plating applied to the inner surface. The EIA 3-1/8” double window assembly was then successfully baked out and tested to 12 kW in a 3-1/8” co-axial system. The thermal gradient across the window was measured to be 90 C which represents about 15 ksi tensile stress in an uncompressed window. In our design the compression was calculated to be about 25 ksi, so the net compressive force was 5 ksi at full power.

  14. Axial field spectrometer at the CERN ISR

    SciTech Connect

    Gordon, H.; Hogue, R.; Killian, T.

    1981-01-01

    The Axial Field Spectrometer (AFS) was recently brought into operation at the CERN ISR. It is being exploited in a wide-ranging program to study different aspects of those proton-proton or proton-antiproton collisions which are characterized by a large transverse momentum (p/sub T/). Examples include the measurement of inclusive distributions of identified high p/sub T/ hadrons, and the study of event structures characterized by a large transverse energy (E/sub T/) or the production of one or several high-p/sub T/ electrons or photons. The experimental approach to this program emphasizes integration of advanced magnetic spectroscopy with state-of-the-art calorimetry. These techniques are fully exploited to provide maximal information on all particles produced. In addition, information from these detectors is used in new ways for on-line event triggering and filtering; this allows even very rare events to be selected with high efficiency, an essential prerequisite for studies at a high-luminosity hadron collider, such as the ISR. Considerable modularity of the detectors was sought. Apart from clear advantages of construction, debugging, running, and servicing of such components, modularity provides ease for addition or reconfiguration of the system to emphasize the study of specific final states. At present, for example, a 1 sr Cerenkov detector system allows hadron identification up to p approx. = 12 GeV/c; liquid-argon electromagnetic calorimeters and a uranium-scintillator calorimeter (Hexagon) are used for a study of events containing direct photons.

  15. Flux, coupling, and selectivity in ionic channels of one conformation.

    PubMed Central

    Chen, D P; Eisenberg, R S

    1993-01-01

    Ions crossing biological membranes are described as a concentration of charge flowing through a selective open channel of one conformation and analyzed by a combination of Poisson and Nernst-Planck equations and boundary conditions, called the PNP theory for short. The ion fluxes in this theory interact much as ion fluxes interact in biological channels and mediated transporters, provided the theoretical channel contains permanent charge and has selectivity created by (electro-chemical) resistance at its ends. Interaction occurs because the flux of different ionic species depends on the same electric field. That electric field is a variable, changing with experimental conditions because the screening (i.e., shielding) of the permanent charge within the channel changes with experimental conditions. For example, the screening of charge and the shape of the electric field depend on the concentration of all ionic species on both sides of the channel. As experimental interventions vary the screening, the electric field varies, and thus the flux of each ionic species varies conjointly, and is, in that sense, coupled. Interdependence and interaction are the rule, independence is the exception, in this channel. PMID:7693003

  16. A non-integral, axial-force measuring element

    NASA Astrophysics Data System (ADS)

    Ringel, M.; Levin, D.; Seginer, A.

    1989-10-01

    A new approach to the measurement of the axial force is presented. A nonintegral axial-force measuring element, housed within the wind-tunnel model, avoids the interactions that are caused by nonlinear elastic phenomena characteristic of integral balances. The new design overcomes other problems, such as friction, misalignment and relative motion between metric elements, that plagued previous attempts at separate measurement of the axial force. Calibration and test results prove the ability of the new approach to duplicate and even surpass the results of much more complicated and expensive integral balances. The advantages of the new design make it the best known solution for particular measurement problems.

  17. Fluorescence Axial Localization with Nanometer Accuracy and Precision

    SciTech Connect

    Li, Hui; Yen, Chi-Fu; Sivasankar, Sanjeevi

    2012-06-15

    We describe a new technique, standing wave axial nanometry (SWAN), to image the axial location of a single nanoscale fluorescent object with sub-nanometer accuracy and 3.7 nm precision. A standing wave, generated by positioning an atomic force microscope tip over a focused laser beam, is used to excite fluorescence; axial position is determined from the phase of the emission intensity. We use SWAN to measure the orientation of single DNA molecules of different lengths, grafted on surfaces with different functionalities.

  18. Innovative Sensors for Pipeline Crawlers: Rotating Permanent Magnet Inspection

    SciTech Connect

    J. Bruce Nestleroth; Richard J. Davis; Stephanie Flamberg

    2006-09-30

    Internal inspection of pipelines is an important tool for ensuring safe and reliable delivery of fossil energy products. Current inspection systems that are propelled through the pipeline by the product flow cannot be used to inspect all pipelines because of the various physical barriers they may encounter. To facilitate inspection of these ''unpiggable'' pipelines, recent inspection development efforts have focused on a new generation of powered inspection platforms that are able to crawl slowly inside a pipeline and can maneuver past the physical barriers that limit internal inspection applicability, such as bore restrictions, low product flow rate, and low pressure. The first step in this research was to review existing inspection technologies for applicability and compatibility with crawler systems. Most existing inspection technologies, including magnetic flux leakage and ultrasonic methods, had significant implementation limitations including mass, physical size, inspection energy coupling requirements and technology maturity. The remote field technique was the most promising but power consumption was high and anomaly signals were low requiring sensitive detectors and electronics. After reviewing each inspection technology, it was decided to investigate the potential for a new inspection method. The new inspection method takes advantage of advances in permanent magnet strength, along with their wide availability and low cost. Called rotating permanent magnet inspection (RPMI), this patent pending technology employs pairs of permanent magnets rotating around the central axis of a cylinder to induce high current densities in the material under inspection. Anomalies and wall thickness variations are detected with an array of sensors that measure local changes in the magnetic field produced by the induced current flowing in the material. This inspection method is an alternative to the common concentric coil remote field technique that induces low-frequency eddy

  19. Interferometric smart material for measuring permanent deformations

    SciTech Connect

    Li, K.

    1996-05-01

    This paper has presented a novel interferometric smart material using closely spaced micro-indentations as sensors for recording permanent deformations. The information can be retrieved from the interference fringe patterns of laser light reflected and diffracted from the ISM indentations. Practically, the interference fringes are monitored with linear photodiode arrays in conjunction with a microcomputer based digital data acquisition system. The measurement can be conducted at any convenient time and needs not conflict with in-situ operations. Validity and accuracy of the method have been confirmed by the comparison with standard measurements. The ISM acts like a smart material to memorize permanent deformations. Different from the ISG and ISR real-time measuring techniques, the ISM measurement may be performed at any convenient time, and large deformations can be measured. The ISM method competes with other optical methods for its extremely compact sensors and applicability to production environments. It measures the indentation separations through analyzing the interference fringe patterns and has a better accuracy than a microscope. It is applicable to curved surfaces and notched regions in large structures.

  20. Influence of relief on permanent preservation areas.

    PubMed

    dos Santos, Alexandre Rosa; Chimalli, Tessa; Peluzio, João Batista Esteves; da Silva, Aderbal Gomes; dos Santos, Gleissy Mary Amaral Dino Alves; Lorenzon, Alexandre Simões; Teixeira, Thaisa Ribeiro; de Castro, Nero Lemos Martins; Soares Ribeiro, Carlos Antonio Alvares

    2016-01-15

    Many countries have environmental legislation to protecting natural resources on private property. In Brazil, the Brazilian Forestry Code determines specific areas to maintain with natural vegetation cover, known as areas of permanent preservation (APP). Currently, there are few studies that relate topographic variables on APP. In this context, we sought to evaluate the influence of relief on the conservation of areas of permanent preservation (APP) in the areas surrounding Caparaó National Park, Brazil. By using the chi-squared statistical test, we verified that the presence of forest cover is closely associated with altitude. The classes of APP in better conservation status are slopes in addition to hilltops and mountains, whereas APP streams and springs are among the areas most affected by human activities. The most deforested areas are located at altitudes below 1100.00 m and on slopes less than 45°. All orientations of the sides were significant for APP conservation status, with the southern, southeastern, and southwestern sides showing the lower degrees of impact. The methodology can be adjusted to environmental legislation to other countries. PMID:26476068

  1. Trading permanent and temporary carbon emissions credits

    SciTech Connect

    Marland, Gregg; Marland, Eric

    2009-08-01

    In this issue of Climatic Change, Van Kooten (2009) addresses an issue that has bedeviled negotiators since the drafting stage of the Kyoto Protocol. If we accept that increasing withdrawals of carbon dioxide from the atmpshere has the same net impact on the climate system as reducing emissions of carbon dioxide to the atmosphere, how do we design a system that allows trading of one for the other? As van Kooten expresses the challenge: 'The problem is that emissions reduction and carbon sequestration, while opposite sides of the same coin in some sense, are not directly comparable, thereby inhibiting their trade in carbon markets.' He explains: 'The difficulty centers on the length of time that mitigation strategies without CO{sub 2} from entering the atmosphere - the duration problem.' While reducing emissions of CO{sub 2} represents an essentially permanent benefit for the atmosphere, capturing CO{sub 2} that has been produced (whether capture is from the atmosphere or directly from, for example, the exhaust from power plants) there is the challenge of storing the carbon adn the risk that it will yet escape to the atmosphere. Permanent benefit to the atmosphere is often not assured for carbon sequestration activities. This is especially true if the carbon is taken up and stored in the biosphere - e.g. in forest trees or agricultural soils.

  2. Real Time Flux Control in PM Motors

    SciTech Connect

    Otaduy, P.J.

    2005-09-27

    Significant research at the Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) is being conducted to develop ways to increase (1) torque, (2) speed range, and (3) efficiency of traction electric motors for hybrid electric vehicles (HEV) within existing current and voltage bounds. Current is limited by the inverter semiconductor devices' capability and voltage is limited by the stator wire insulation's ability to withstand the maximum back-electromotive force (emf), which occurs at the upper end of the speed range. One research track has been to explore ways to control the path and magnitude of magnetic flux while the motor is operating. The phrase, real time flux control (RTFC), refers to this mode of operation in which system parameters are changed while the motor is operating to improve its performance and speed range. RTFC has potential to meet an increased torque demand by introducing additional flux through the main air gap from an external source. It can augment the speed range by diverting flux away from the main air gap to reduce back-emf at high speeds. Conventional RTFC technology is known as vector control [1]. Vector control decomposes the stator current into two components; one that produces torque and a second that opposes (weakens) the magnetic field generated by the rotor, thereby requiring more overall stator current and reducing the efficiency. Efficiency can be improved by selecting a RTFC method that reduces the back-emf without increasing the average current. This favors methods that use pulse currents or very low currents to achieve field weakening. Foremost in ORNL's effort to develop flux control is the work of J. S. Hsu. Early research [2,3] introduced direct control of air-gap flux in permanent magnet (PM) machines and demonstrated it with a flux-controlled generator. The configuration eliminates the problem of demagnetization because it diverts all the flux from the magnets instead of

  3. Hybrid permanent magnet gradient dipoles for the recycler ring at Fermilab

    SciTech Connect

    Brown, B.C.; Dimarco, J.; Foster, G.W.; Glass, H.D.; Haggard, J.E.; Harding, D.J.; Jackson, G.R.; May, M.R. Nicol, T.H.; Ostiguy, J.-F.; Schlabach, R.; Volk, J.T.

    1997-11-01

    Hybrid permanent magnets provide the magnetic fields for an anti- proton storage ring which is under construction at Fermilab. Using a combined function lattice, gradient magnets provide the bending, focusing and sextupole correction for the regular cells. Shorter magnets without sextupole are used in dispersion suppressor cells. These magnets use a 4.7 m ( 3 m) long iron shell for flux return, bricks of 25.4 mm thick strontium ferrite supply the flux and transversely tapered iron poles separated by aluminum spacers set the shape of the magnetic field. Central fields of 0.14 T with gradients of {approx}6%/inch ({approx}13%/inch) are required. Field errors are expected to be less than 10{sup -4} of the bend field over an aperture of {+-}40 mm (horizontal) {times} {+-}20 mm (vertical). Design, procurement, fabrication, pole potential adjustment, field shape trimming and measured fields will be reported.

  4. Heat flux characteristics in an atmospheric double arc argon plasma jet

    SciTech Connect

    Tu Xin; Yu Liang; Yan Jianhua; Cen Kefa; Cheron, Bruno

    2008-10-13

    In this study, the axial evolution of heat flux excited by a double arc argon plasma jet impinging on a flat plate is determined, while the nonstationary behavior of the heat flux is investigated by combined means of the fast Fourier transform, Wigner distribution, and short-time Fourier transform. Two frequency groups (<1 and 2-10 kHz) are identified in both the Fourier spectrum and the time-frequency distributions, which suggest that the nature of fluctuations in the heat flux is strongly associated with the dynamic behavior of the plasma arc and the engulfment of ambient air into different plasma jet regions.

  5. Initial assessment of the performance of an 0.3 T permanent magnet in whole body NMR imaging.

    PubMed

    Keeler, E K; Giambalvo, A; Smith, S D; Negendank, W

    1983-01-01

    An 0.3 Tesla permanent magnet was constructed and incorporated into a complete whole body NMR imager. Axial, sagittal and coronal images from human subjects were obtained using a two-dimensional Fourier Transform analysis of selected planes 8 mm thick, combined with an efficient multislice technique that produces sections centered 12 mm apart. Images were obtained based on inversion recovery and spin echo modes. The permanent magnetic field is uniform to 10 ppm over 38 cm. The magnet requires no special maintenance and has an extremely small fringe field. The magnet design, with its field vertical to the long axis of the subject, permits use of a solenoidal radiofrequency receiving coil for optimal signal-to-noise ratio. Images were shown that are of high quality and produced under conditions simulating those necessary for efficient patient throughout in a clinical setting. Many of the unique features of NMR imaging, such as ability to directly obtain axial, sagittal and coronal projections, the variety of imaging modes, the natural sources of contrast, and the ability to visualize clearly medium and large blood vessels, were demonstrated.

  6. Numerical analysis of cocurrent conical and cylindrical axial cyclone separators

    NASA Astrophysics Data System (ADS)

    Nor, M. A. M.; Al-Kayiem, H. H.; Lemma, T. A.

    2015-12-01

    Axial concurrent liquid-liquid separator is seen as an alternative unit to the traditional tangential counter current cyclone due to lower droplet break ups, turbulence and pressure drop. This paper presents the numerical analysis of a new conical axial cocurrent design along with a comparison to the cylindrical axial cocurrent type. The simulation was carried out using CFD technique in ANSYS-FLUENT software. The simulation results were validated by comparison with experimental data from literature, and mesh independency and quality were performed. The analysis indicates that the conical version achieves better separation performance compared to the cylindrical type. Simulation results indicate tangential velocity with 8% higher and axial velocity with 80% lower recirculation compared to the cylindrical type. Also, the flow visualization counters shows smaller recirculation region relative to the cylindrical unit. The proposed conical design seems more efficient and suits the crude/water separation in O&G industry.

  7. 22. Axial view along north cell corridor, cells at right; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. Axial view along north cell corridor, cells at right; view to southwest, 65mm lens with electronic flash illumination. - Tule Lake Project Jail, Post Mile 44.85, State Route 139, Newell, Modoc County, CA

  8. 20. INTERIOR AXIAL VIEW OF THE THEATER IN BUILDING 746, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. INTERIOR AXIAL VIEW OF THE THEATER IN BUILDING 746, LOOKING SOUTHWEST. - Oakland Naval Supply Center, Gymnasium-Cafeteria-Theater, East K Street between Eleventh & Twelfth Streets, Oakland, Alameda County, CA

  9. 22. INTERIOR AXIAL VIEW OF THE THEATER LOOKING TOWARD THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. INTERIOR AXIAL VIEW OF THE THEATER LOOKING TOWARD THE BALCONY, BUILDING 746, LOOKING NORTH. - Oakland Naval Supply Center, Gymnasium-Cafeteria-Theater, East K Street between Eleventh & Twelfth Streets, Oakland, Alameda County, CA

  10. Axial symmetry, anti-BRST invariance, and modified anomalies

    NASA Astrophysics Data System (ADS)

    Varshovi, Amir Abbass

    2016-07-01

    It is shown that, anti-BRST symmetry is the quantized counterpart of local axial symmetry in gauge theories. An extended form of descent equations is worked out, which yields a set of modified consistent anomalies.

  11. Nonparallel stability of the flow in an axially rotating pipe

    NASA Astrophysics Data System (ADS)

    del Pino, C.; Ortega-Casanova, J.; Fernandez-Feria, R.

    2003-08-01

    The linear stability of the developing flow in an axially rotating pipe is analyzed using parabolized stability equations (PSE). The results are compared with those obtained from a near-parallel stability approximation that only takes into account the axial variation of the basic flow. Though the PSE results obviously coincide with the near-parallel ones far downstream, when the flow has reached a Hagen-Poiseuille axial velocity profile with superimposed solid-body rotation, they differ significantly in the developing region. Therefore, the onset of instability strongly depends on the axial evolution of the perturbations. The PSE results are also compared with experimental data from Imao et al. [Exp. Fluids 12 (1992) 277], showing a good agreement in the frequencies and wavelengths of the unstable disturbances, that take the form of spiral waves. Finally, a simple method for detecting one of the conditions to characterize the onset of absolute instability using PSE is given.

  12. Nonparallel stability of the flow in an axially rotating pipe

    NASA Astrophysics Data System (ADS)

    del Pino, Carlos; Ortega-Casanova, Joaquin; Fernandez-Feria, Ramon

    2002-11-01

    The linear stability of the developing flow in an axially rotating pipe is analyzed using parabolized stability equations (PSE). The results are compared with those obtained from a near-parallel stability approximation that only takes into account the axial variation of the basic flow. Though the PSE results obviously coincide with the near-parallel ones far downstream, when the flow has reached a Hagen-Poiseuille axial velocity profile with superimposed solid body rotation, they differ significantly in the developing region. Therefore, the onset of instability strongly depends on the axial evolution of the perturbations. The PSE results are also compared with experimental data from Imao et al. [Exp. Fluids 12, 277-285 (1992)], showing a good agreement in the frequencies and wavelengths of the unstable disturbances, that take the form of spiral waves. Finally, a simple method to characterize the onset of absolute instability using PSE is given.

  13. PRELIMINARY DESIGN ANALYSIS OF AXIAL FLOW TURBINES

    NASA Technical Reports Server (NTRS)

    Glassman, A. J.

    1994-01-01

    A computer program has been developed for the preliminary design analysis of axial-flow turbines. Rapid approximate generalized procedures requiring minimum input are used to provide turbine overall geometry and performance adequate for screening studies. The computations are based on mean-diameter flow properties and a stage-average velocity diagram. Gas properties are assumed constant throughout the turbine. For any given turbine, all stages, except the first, are specified to have the same shape velocity diagram. The first stage differs only in the value of inlet flow angle. The velocity diagram shape depends upon the stage work factor value and the specified type of velocity diagram. Velocity diagrams can be specified as symmetrical, zero exit swirl, or impulse; or by inputting stage swirl split. Exit turning vanes can be included in the design. The 1991 update includes a generalized velocity diagram, a more flexible meanline path, a reheat model, a radial component of velocity, and a computation of free-vortex hub and tip velocity diagrams. Also, a loss-coefficient calibration was performed to provide recommended values for airbreathing engine turbines. Input design requirements include power or pressure ratio, mass flow rate, inlet temperature and pressure, and rotative speed. The design variables include inlet and exit diameters, stator angle or exit radius ratio, and number of stages. Gas properties are input as gas constant, specific heat ratio, and viscosity. The program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, flow angles, blading angles, and last stage absolute and relative Mach numbers. This program is written in FORTRAN 77 and can be ported to any computer with a standard FORTRAN compiler which supports NAMELIST. It was originally developed on an IBM 7000 series computer running VM and has been implemented on IBM PC computers and compatibles running MS-DOS under Lahey FORTRAN, and

  14. Aerodynamics and combustion of axial swirlers

    NASA Astrophysics Data System (ADS)

    Fu, Yongqiang

    A multipoint lean direct injection (LDI) concept was introduced recently in non-premixed combustion to obtain both low NOx emissions and good combustion stability. In this concept, a key feature is the injection of finely atomized fuel into the high-swirling airflow at the combustor dome that provides a homogenous, lean fuel-air mixture. In order to achieve the fine atomization and mixing of the fuel and air quickly and uniformly, a good swirler design should be studied. The focus of this dissertation is to investigate the aerodynamics and combustion of the swirling flow field in a multipoint Lean Direct Injector combustor. A helical axial-vaned swirler with a short internal convergent-divergent venturi was used. Swirlers with various vane angles and fuel nozzle insertion lengths have been designed. Three non-dimensional parameter effects on non-reacting, swirling flow field were studied: swirler number, confinement ratio and Reynolds number. Spray and combustion characteristics on the single swirler were studied to understand the mechanism of fuel-air mixing in this special configuration. Multi-swirler interactions were studied by measuring the confined flow field of a multipoint swirler array with different configurations. Two different swirler arrangements were investigated experimentally, which include a co-swirling array and a counter-swirling array. In order to increase the range of stability of multipoint LDI combustors, an improved design were also conducted. The results show that the degree of swirl and the level of confinement have a clear impact on the mean and turbulent flow fields. The swirling flow fields may also change significantly with the addition of a variety of simulated fuel nozzle insertion lengths. The swirler with short insertion has the stronger swirling flow as compared with the long insertion swirler. Reynolds numbers, with range of current study, will not alter mean and turbulent properties of generated flows. The reaction of the spray

  15. Light-front view of the axial anomaly

    SciTech Connect

    Ji, Chueng-Ryong |; Rey, Soo-Jong

    1995-07-01

    Motivated by an apparent puzzle of the light-front vacua incompatible with the axial anomaly, we have considered the two-dimensional massless Schwinger model for an arbitrary interpolating angle of the quantization surface. By examining spectral deformation of the Dirac sea under an external electric field semiclassically, we have found that the axial anomaly is quantization angle independent. This indicates an intricate nontrivial vacuum structure present even in the light-front limit.

  16. Axially astigmatic surfaces: different types and their properties

    NASA Astrophysics Data System (ADS)

    Malacara-Doblado, Daniel; Malacara-Hernandez, Daniel; Garcia-Marquez, Jorge L.

    1996-12-01

    Axially astigmatic surfaces have different curvatures in orthogonal diameters. Toroidal and spherocylindrical optical surfaces are two mathematically different special cases of axially astigmatic surfaces as noted by Menchaca and Malacara (1986), but they are almost identical in the vicinity of the optical axis. The different between these two surfaces increases when the distance to the optical axis increases. We study the general properties of astigmatic surfaces and some special interesting cases.

  17. Mapping AUV Survey of Axial Seamount

    NASA Astrophysics Data System (ADS)

    Thomas, H.; Caress, D.; Conlin, D.; Clague, D.; Paduan, J.; Butterfield, D.; Chadwick, W.; Tucker, P.

    2006-12-01

    In late August and early September 2006, the MBARI Mapping Autonomous Underwater Vehicle (AUV) was deployed for 5 missions on Axial Seamount during a NOAA NeMO cruise on the R/V Thompson. The objective of the survey was to determine the geologic history of the summit of Axial Seamount using high resolution multibeam, sidescan, and sub-bottom profiler data. The Mapping AUV is a torpedo-shaped, 6000 m rated vehicle designed and constructed by MBARI. The vehicle is equipped with a 200 kHz multibeam sonar, 110 kHz and 410 kHz chirp sidescan sonar, and a 2-16 kHz sweep chirp sub-bottom profiler. The multibeam provides a 120-degree swath with 0.94 degree by 0.94 degree beam resolution. The endurance of the AUV is eight hours at 3 knots. Navigation derives from an inertial navigation system (INS) incorporating a ring laser gyro aided by GPS at the surface and by velocity-over- ground observations from a Doppler velocity log (DVL) when within 130 m of the seafloor. A navigational precision of 0.05 percent of distance traveled is achieved with continuous DVL bottom lock. An acoustic modem allows surface aiding of navigation during deep descents. The AUV ran two types of missions: those on the rim of the caldera were run at 90 m altitude with a line spacing of 250 m and those on the caldera floor were run at 50 m altitude with a line spacing of 150 or 175 m. The surveys covered most of 1998 lava flow on the south rim of the caldera and northern part of the south rift zone, the southern region of the caldera floor where hydrothermal vents are common, the northeast rim of the caldera where volcaniclastic deposits related to caldera collapse drape the surface, the north rift zone, and the northern portion of the caldera floor. The low-altitude maps have a resolution of 1 m, so large individual lava pillars and hydrothermal chimneys can be seen, fissures stand out clearly, and the regions of collapsed lobate flows and lava channels are prominent. Many of the flows, including the

  18. Superradiance and flux conservation

    NASA Astrophysics Data System (ADS)

    Boonserm, Petarpa; Ngampitipan, Tritos; Visser, Matt

    2014-09-01

    The theoretical foundations of the phenomenon known as superradiance still continue to attract considerable attention. Despite many valiant attempts at pedagogically clear presentations, the effect nevertheless still continues to generate some significant confusion. Part of the confusion arises from the fact that superradiance in a quantum field theory context is not the same as superradiance (superfluorescence) in some condensed matter contexts; part of the confusion arises from traditional but sometimes awkward normalization conventions, and part is due to sometimes unnecessary confusion between fluxes and probabilities. We shall argue that the key point underlying the effect is flux conservation (and, in the presence of dissipation, a controlled amount of flux nonconservation), and that attempting to phrase things in terms of reflection and transmission probabilities only works in the absence of superradiance. To help clarify the situation we present a simple exactly solvable toy model exhibiting both superradiance and damping.

  19. Flux amplification in SSPX

    NASA Astrophysics Data System (ADS)

    Lodestro, Lynda; Hooper, E. B.; Jayakumar, R. J.; Pearlstein, L. D.; Wood, R. D.; McLean, H. S.

    2007-11-01

    Flux amplification---the ratio of poloidal flux enclosed between the magnetic and geometric axes to that between the separatrix and the geometric axis---is a key measure of efficiency for edge-current-driven spheromaks. With the new, modular capacitor bank, permitting flexible programming of the gun current, studies of flux amplification under various drive scenarios can be performed. Analysis of recent results of pulsed operation with the new bank finds an efficiency ˜ 0.2, in selected shots, of the conversion of gun energy to confined magnetic energy during the pulses, and suggests a route toward sustained efficiency at 0.2. Results of experiments, a model calculation of field build-up, and NIMROD simulations exploring this newly suggested scenario will be presented.

  20. Interaction between propulsion and levitation system in the HTSC-permanent magnet conveyance system

    NASA Astrophysics Data System (ADS)

    Ohashi, S.; Nishio, R.; Hashikawa, T.

    2010-11-01

    The magnetically levitated conveyance system has been developed. Pinning force of high temperature bulk superconductors (HTSC) are used for the levitation and the guidance of the carrier. The magnetic rail is set on the ground, and flux from the magnetic rail is pinned by HTSCs on the carrier body. To increase the load weight, the repulsive force of the permanent magnet is introduced. The hybrid levitation system is composed. The repulsive force by the permanent magnet between the load stage on the carrier and the magnetic rail on the ground is used to support the load weight. As the load stage is connected to the carrier body by the linear sliders, the mass of the load weight does not act on the carrier body. The interaction between the electromagnet and the permanent magnet under the load stage generates the propulsion force. The electromagnet is constructed by the air core coils, and excited only when the load stage passes. The interaction between the propulsion and the levitation system is investigated. Disturbance of the propulsion system on the levitation and the guidance force is measured. The results show the influence of the propulsion electromagnet on the pinning force is little, and this propulsion system works effectively.

  1. Reduction of Cogging Torque in Dual Rotor Permanent Magnet Generator for Direct Coupled Wind Energy Systems

    PubMed Central

    Paulsamy, Sivachandran

    2014-01-01

    In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions. PMID:25202746

  2. Impact of permanent inundation on methane emissions from a Spartina alterniflora coastal salt marsh

    NASA Astrophysics Data System (ADS)

    Ding, Weixin; Zhang, Yaohong; Cai, Zucong

    2010-10-01

    To understand the effect of water level on CH 4 emissions from an invasive Spartina alterniflora coastal brackish marsh, we measured CH 4 emissions from intermittently and permanently (5 cm water depth) inundated mesocosms with or without N fertilizer added at a rate of 2.7 g N m -2. Dissolved CH 4 concentrations in porewater and vertically-profiled sediment redox potential were measured, as were aboveground biomass and stem density of S. alterniflora. Mean CH 4 fluxes during the growing season in permanently inundated mesocosms without and with N fertilizer were 1.03 and 1.73 mg CH 4 m -2 h -1, respectively, which were significantly higher than in the intermittently inundated mesocosms. This response indicates that prolonged submergence of sediment, up to a water depth of 5 cm, stimulated CH 4 release. Inundation did not greatly affect aboveground biomass and stem density, but did significantly reduce redox potential in sediment, which in turn stimulated CH 4 production and increased the CH 4 concentration of porewater, resulting in higher CH 4 emission in the mesocosm. Our data showed that the stimulatory effect of shallow, permanent inundation on CH 4 emission in S. alterniflora marsh sediment was due primarily to an improved methanogenic environment rather than an increase in plant-derived substrates and/or the number of gas emission pathways through the plant's aerenchymal system.

  3. Reduction of cogging torque in dual rotor permanent magnet generator for direct coupled wind energy systems.

    PubMed

    Paulsamy, Sivachandran

    2014-01-01

    In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

  4. Reactive control of subsonic axial fan noise in a duct.

    PubMed

    Liu, Y; Choy, Y S; Huang, L; Cheng, L

    2014-10-01

    Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical.

  5. Research on axial support technology of large aperture primary mirror

    NASA Astrophysics Data System (ADS)

    Yao, Hui

    2010-05-01

    In ground-based optical detection system, when large aperture primary mirror in a different pitch angle detection, the surface shape error of primary mirror is affected by its weight deformation, and the surface shape error of primary mirror is one of the key factors affecting imaging quality. The primary mirror support system, including axial support and radial support, and the axial support is main factor affecting the surface shape error of primary mirror, the position and number of axial support is very important for surface shape error of primary mirror. The support technology of Φ1.2m primary mirror was studied detailedly in this paper, the parameterized model of primary mirror was built based on ANSYS, the relationship between the surface shape error of primary mirror and the ratio of its diameter to thickness was analyzed, the axial support was optimized, and the support-ring number, support-ring radius and support point position of axial support were optimum designed. The result of analysis showed that the Root-Mean-Square (RMS) value of the surface shape error of primary mirror was 1.8 nm, when the primary mirror pointed to zenith, met to the design need of the optical system, and the axial support system was verified.

  6. Reactive control of subsonic axial fan noise in a duct.

    PubMed

    Liu, Y; Choy, Y S; Huang, L; Cheng, L

    2014-10-01

    Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical. PMID:25324066

  7. Permanent junctional reciprocating tachycardia in a dog.

    PubMed

    Santilli, Roberto A; Santos, Luis F N; Perego, Manuela

    2013-09-01

    A 5-year-old male English Bulldog was presented with a 1-year history of paroxysmal supraventricular tachycardia (SVT) partially responsive to amiodarone. At admission the surface ECG showed sustained runs of a narrow QRS complex tachycardia, with a ventricular cycle length (R-R interval) of 260 ms, alternating with periods of sinus rhythm. Endocardial mapping identified the electrogenic mechanism of the SVT as a circus movement tachycardia with retrograde and decremental conduction along a concealed postero-septal atrioventricular pathway (AP) and anterograde conduction along the atrioventricular node. These characteristics were indicative of a permanent junctional reciprocating tachycardia (PJRT). Radiofrequency catheter ablation of the AP successfully terminated the PJRT, with no recurrence of tachycardia on Holter monitoring at 12 months follow-up.

  8. Permanent electric dipole moment of molybdenum carbide

    NASA Astrophysics Data System (ADS)

    Wang, Hailing; Virgo, Wilton L.; Chen, Jinhai; Steimle, Timothy C.

    2007-09-01

    High resolution optical spectroscopy has been used to study a molecular beam of molybdenum monocarbide (MoC). The Stark effect of the Re(0) and Qfe(1) branch features of the [18.6]Π13-XΣ-3(0,0) band system of Mo98C were analyzed to determine the permanent electric dipole moments μe of 2.68(2) and 6.07(18)D for the [18.6]Π13(ν =0) and XΣ-3(ν =0) states, respectively. The dipole moments are compared with the experimental value for ruthenium monocarbide [T. C. Steimle et al., J. Chem. Phys. 118, 2620 (2003)] and with theoretical predictions. A molecular orbital correlation diagram is used to interpret the observed and predicted trends of ground state μe values for the 4d-metal monocarbides series.

  9. Object permanence in common marmosets (Callithrix jacchus).

    PubMed

    Mendes, Natacha; Huber, Ludwig

    2004-03-01

    A series of 9 search tasks corresponding to the Piagetian Stages 3-6 of object permanence were administered to 11 common marmosets (Callithrix jacchus). Success rates varied strongly among tasks and marmosets, but the performances of most subjects were above chance level on the majority of tasks of visible and invisible displacements. Although up to 24 trials were administered in the tests, subjects did not improve their performance across trials. Errors were due to preferences for specific locations or boxes, simple search strategies, and attentional deficits. The performances of at least 2 subjects that achieved very high scores up to the successive invisible displacement task suggest that this species is able to represent the existence and the movements of unperceived objects.

  10. Permanent cardiac pacing in Malaysia. An update.

    PubMed

    Saw, H S; Chong, K T; Singham, A M

    1981-10-01

    Updated data on permanent cardiac pacing in Malaysia is presented. Over the past 3 1/2 years (1976-1980), 75 patients underwent insertion of pacemakers giving an annual incidence of about 20 cases as compared with a total of 21 cases in the previous 8 years (1968-1977). Many of the features reported in an earlier paper in 1977 viz mode of presentation, age and sex distribution and indications for pacing remain unchanged. Over this period only 4 patients required lead replacement. Since concentrating mainly on the use of epicardial leads implanted via a subxiphoid approach, complications have been remarkably low. The problem of availability of pacemakers has been averted. Cost remains a major consideration when recommending one pacemaker in preference over another. The details concerning clinical features, indications for pacing, complications and other problems encountered in the management of these patients are discussed.

  11. Permanent Cortical Blindness After Bronchial Artery Embolization

    SciTech Connect

    Doorn, Colette S. van De Boo, Diederick W.; Weersink, Els J. M.; Delden, Otto M. van Reekers, Jim A. Lienden, Krijn P. van

    2013-12-15

    A 35-year-old female with a known medical history of cystic fibrosis was admitted to our institution for massive hemoptysis. CTA depicted a hypertrophied bronchial artery to the right upper lobe and showed signs of recent bleeding at that location. Bronchial artery embolization (BAE) was performed with gelfoam slurry, because pronounced shunting to the pulmonary artery was present. Immediately after BAE, the patient developed bilateral cortical blindness. Control angiography showed an initially not opacified anastomosis between the embolized bronchial artery and the right subclavian artery, near to the origin of the right vertebral artery. Cessation of outflow in the bronchial circulation reversed the flow through the anastomosis and allowed for spill of embolization material into the posterior circulation. Unfortunately the cortical blindness presented was permanent.

  12. Levitation forces in bearingless permanent magnet motors

    SciTech Connect

    Amrhein, W.; Silber, S.; Nenninger, K.

    1999-09-01

    Bearingless motors combine brushless AC-motors with active magnetic bearings by the integration of two separate winding systems (torque and radial levitation force windings with different pole pairs) in one housing. This paper gives an insight into the influences of the motor design on the levitation force and torque generation. It is shown that especially for machines with small air gaps it can be very important to choose the right design parameters. Increasing the permanent magnet height in order to increase the motor torque can result in a remarkable reduction of radial forces. The interrelationships are discussed on the basis of Maxwell and Lorentz forces acting upon the stator surface. The investigations are presented for a bearingless low cost motor, suited for pump, fan or blower applications. The presented motor needs only four coils for operation.

  13. Experience with the SLC permanent magnet multipoles

    SciTech Connect

    Gross, G.; Spencer, J.

    1994-06-01

    Permanent magnets have been used in the SLC Damping Rings and their injection and extraction lines since 1985. Recent upgrades of the DR vacuum chambers provided an opportunity to check DR magnets prior to higher beam current operation. Several PM sextupoles downstream of the injection kickers in the electron ring had exceeded their thermal stabilization values of 80{degrees}C and some showed serious mechanical deformations and radiation >1 R at contact. We discuss our observations, measurements and a few inexpensive modifications that should improve these magnets under such conditions. A new, block matching algorithm allowed us to use magnet blocks that had been considered unusable because of very different remament field strengths and easy axis errors.

  14. Variable-field permanent magnet dipole

    SciTech Connect

    Barlow, D.B.; Kraus, R.H. Jr.; Meyer, R.E.

    1993-10-01

    A new concept for a variable-field permanent-magnet dipole (VFPMD) has been designed, fabricated, and tested at Los Alamos. The VFPMD is a C-shaped sector magnet with iron poles separated by a large block of magnet material (SmCo). The central field can be continuously varied from 0.07 T to 0.3 T by moving an iron shunt closer or further away from the back of the magnet. The shunt is specially shaped to make the dependence of the dipole field strength on the shunt position as linear as possible. The dipole has a 2.8 cm high by 8 cm wide aperture with {approximately}10 cm long poles.

  15. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MaCarthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  16. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MacArthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator wherein each thermographic layer comprises a plurality of respective thermographic phosphors. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  17. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MacArthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator, wherein each thermographic layer comprises a plurality of respective thermographic sensors in a juxtaposed relationship with respect to each other. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  18. Angular momentum flux of nonparaxial acoustic vortex beams and torques on axisymmetric objects.

    PubMed

    Zhang, Likun; Marston, Philip L

    2011-12-01

    An acoustic vortex in an inviscid fluid and its radiation torque on an axisymmetric absorbing object are analyzed beyond the paraxial approximation to clarify an analogy with an optical vortex. The angular momentum flux density tensor from the conservation of angular momentum is used as an efficient description of the transport of angular momentum. Analysis of a monochromatic nonparaxial acoustic vortex beam indicates that the local ratio of the axial (or radial) flux density of axial angular momentum to the axial (or radial) flux density of energy is exactly equal to the ratio of the beam's topological charge l to the acoustic frequency ω. The axial radiation torque exerted by the beam on an axisymmetric object centered on the beam's axis due to the transfer of angular momentum is proportional to the power absorbed by the object with a factor l/ω, which can be understood as a result of phonon absorption from the beam. Depending on the vortex's helicity, the torque is parallel or antiparallel to the beam's axis.

  19. First results from the permanent SO2 Camera system at Stromboli

    NASA Astrophysics Data System (ADS)

    Salerno, Giuseppe G.; Burton, Mike; Caltabiano, Tommaso; D'Auria, Luca; Maugeri, Roberto; Mure, Filippo

    2015-04-01

    Since the 1980's volcano monitoring has undergone stunning changes, evolving from descriptive and sparse observations to a systematic-quantitative approach of science and technology. Surveillance of chemical gas composition and their emission rate is a vital part of efforts in interpreting volcanic activity of observatories since their changes are closely linked with seismicity and deformation swings. In this unruly technology progression, volcanic gas sensing observations have also undergone a profound revolution, for example by increasing observation frequency of SO2 flux from a few samples per day to Hz. In May 2013, a permanent-robotic SO2 dual-camera system was installed by the Istituto Nazionale di Geofisica e Vulcanologia at Stromboli as a part of the ultraviolet scanning spectrometers network FLAME, with the intent to underpin the geochemical surveillance and shed light on degassing and volcanic processes. Here, we present the first results of SO2 flux observed by the permanent SO2 camera system in the period between May 2013 and April 2015. Results are corroborated with the well established FLAME ultraviolet scanning network and also compared with VLP signals from the seismic network.

  20. Dynamic model tracking design for low inertia, high speed permanent magnet ac motors.

    PubMed

    Stewart, P; Kadirkamanathan, V

    2004-01-01

    Permanent magnet ac (PMAC) motors have existed in various configurations for many years. The advent of rare-earth magnets and their associated highly elevated levels of magnetic flux makes the permanent magnet motor attractive for many high performance applications from computer disk drives to all electric racing cars. The use of batteries as a prime storage element carries a cost penalty in terms of the unladen weight of the vehicle. Minimizing this cost function requires the minimum electric motor size and weight to be specified, while still retaining acceptable levels of output torque. This tradeoff can be achieved by applying a technique known as flux weakening which will be investigated in this paper. The technique allows the speed range of a PMAC motor to be greatly increased, giving a constant power range of more than 4:1. A dynamic model reference controller is presented which has advantages in ease of implementation, and is particularly suited to dynamic low inertia applications such as clutchless gear changing in high performance electric vehicles. The benefits of this approach are to maximize the torque speed envelope of the motor, particularly advantageous when considering low inertia operation. The controller is examined experimentally, confirming the predicted performance.

  1. [Research advances in ecosystem flux].

    PubMed

    Zhang, Xudong; Peng, Zhenhua; Qi, Lianghua; Zhou, Jinxing

    2005-10-01

    To develop the long-term localized observation and investigation on ecosystem flux is of great importance. On the basis of generalizing the concepts and connotations of ecosystem flux, this paper introduced the construction and development histories of Global Flux Networks, Regional Flux Networks (Ameri-Flux, Euro-Flux and Asia-Flux) and China-Flux, as well as the main methodologies, including micrometeorological methods (such as eddy correlation method, mass balance method, energy balance method and air dynamic method)and chamber methods (static and dynamic chamber methods), and their basic operation principles. The research achievements, approaches and advances of CO2, N2O, CH4, and heat fluxes in forest ecosystem, farmland ecosystem, grassland ecosystem and water ecosystem were also summarized. In accordance with the realities and necessities of ecosystem flux research in China, some suggestions and prospects were put forward.

  2. Earliest stages of the nonequilibrium in axially symmetric, self-gravitating, dissipative fluids

    NASA Astrophysics Data System (ADS)

    Herrera, L.; Di Prisco, A.; Ospino, J.; Carot, J.

    2016-09-01

    We report a study on axially and reflection symmetric dissipative fluids, just after its departure from hydrostatic and thermal equilibrium, at the smallest time scale at which the first signs of dynamic evolution appear. Such a time scale is smaller than the thermal relaxation time, the thermal adjustment time, and the hydrostatic time. It is obtained that the onset of nonequilibrium will critically depend on a single function directly related to the time derivative of the vorticity. Among all fluid variables (at the time scale under consideration), only the tetrad component of the anisotropic tensor in the subspace orthogonal to the four-velocity and the Killing vector of axial symmetry, shows signs of dynamic evolution. Also, the first step toward a dissipative regime begins with a nonvanishing time derivative of the heat flux component along the meridional direction. The magnetic part of the Weyl tensor vanishes (not so its time derivative), indicating that the emission of gravitational radiation will occur at later times. Finally, the decreasing of the effective inertial mass density, associated to thermal effects, is clearly illustrated.

  3. Axial and diffusion models of the laser pulse propagation in a highly-scattering medium

    SciTech Connect

    Tereshchenko, Sergei A; Danilov, Arsenii A; Podgaetskii, Vitalii M; Vorob'ev, Nikolai S

    2004-06-30

    The propagation of laser radiation through a layer of a highly-scattering medium (HSM) is considered on the basis of two theoretical models: a nonstationary axial (two-flux) model and a nonstationary diffusion model. Analytic expressions for the temporal distributions of the photons of an ultrashort laser pulse transmitted through the HSM are presented. Experimental temporal distributions are used to obtain the parameters of models corresponding to an HSM, to determine the theoretical temporal distributions, and to compare them with the experimental curves. These two theoretical models are compared quantitatively for the first time. Their advantages and drawbacks that must be considered in the development of HSM transmission optical tomography are pointed out. (light scattering)

  4. Magnetospheric environments of outer planet rings - influence of Saturn's axially symmetric magnetic field

    SciTech Connect

    Hood, L.L.

    1987-07-01

    Saturn's main rings exist within a zone of negligible magnetospheric losses and surface alteration effects, substantially due to the solid-body absorption of inwardly diffusing magnetospheric particles. This process is presently shown to be especially efficient in the inner magnetosphere of Saturn, due to the near-axial symmetry of the planetary magnetic field relative to the equatorial rotation plane; under the assumption of comparable diffusion rates, the inward magnetospheric particle transport is far more inhibited in the inner Saturnian magnetosphere than in the same regions of Jupiter and Uranus, even when only rings of comparable widths and depths are considered. In light of this, ring particle surface exposure to the ion fluxes of the radiation belt remains a prepossessing rationale for low Uranian ring albedos. 86 references.

  5. Combined correlation estimation of axial displacement in optical coherence elastography: assessment of axial displacement sensitivity performance relative to existing methods

    NASA Astrophysics Data System (ADS)

    Grimwood, A.; Messa, A.; Bamber, J. C.

    2015-03-01

    A combined correlation method is introduced to optical coherence elastography for axial displacement estimation. Its performance is compared with that of amplitude correlation tracking and phase shift estimation. Relative sensitivities to small (sub-micron), and large (pixel-scale) axial displacements are analysed for a Perspex test object and gelatine phantom. The combined correlation method exhibited good overall performance, with a larger dynamic range than phase shift estimation and higher sensitivity than amplitude correlation tracking.

  6. 15 CFR 1180.10 - NTIS permanent repository.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) TECHNOLOGY ADMINISTRATION, DEPARTMENT OF COMMERCE TRANSFER BY FEDERAL AGENCIES OF SCIENTIFIC, TECHNICAL AND ENGINEERING INFORMATION TO THE NATIONAL TECHNICAL INFORMATION SERVICE § 1180.10 NTIS permanent repository....

  7. 15 CFR 1180.10 - NTIS permanent repository.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) TECHNOLOGY ADMINISTRATION, DEPARTMENT OF COMMERCE TRANSFER BY FEDERAL AGENCIES OF SCIENTIFIC, TECHNICAL AND ENGINEERING INFORMATION TO THE NATIONAL TECHNICAL INFORMATION SERVICE § 1180.10 NTIS permanent repository....

  8. 15 CFR 1180.10 - NTIS permanent repository.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) TECHNOLOGY ADMINISTRATION, DEPARTMENT OF COMMERCE TRANSFER BY FEDERAL AGENCIES OF SCIENTIFIC, TECHNICAL AND ENGINEERING INFORMATION TO THE NATIONAL TECHNICAL INFORMATION SERVICE § 1180.10 NTIS permanent repository....

  9. Simultaneous axial conduction in the fluid and the pipe wall for forced convective laminar flow with blowing and suction at the wall

    NASA Technical Reports Server (NTRS)

    Faghri, Amir; Chen, Ming-Ming; Mahefkey, E. T.

    1989-01-01

    Numerical solutions are reported for conjugate heat transfer in a porous pipe having an internal flow with blowing or suction at the inner surface of the pipe and constant heat flux at the outer surface. The effect of the simultaneous axial conduction through the wall and the fluid has been studied for the combined hydrodynamic and thermal entry lengths. The results show that the ratio of the thermal conductivities of the pipe wall to the fluid and the thickness of the pipe wall may become significant factors on the heat transfer when the Peclet number is small, especially for the case when fluid is injected into the pipe. It is also shown that the effect of axial wall conduction for the case of constant heat flux at the outer wall surface can be neglected when the wall thickness is small and the ratio of the conductivities of the wall to the fluid approaches unity.

  10. High flux heat exchanger

    NASA Astrophysics Data System (ADS)

    Flynn, Edward M.; Mackowski, Michael J.

    1993-01-01

    This interim report documents the results of the first two phases of a four-phase program to develop a high flux heat exchanger for cooling future high performance aircraft electronics. Phase 1 defines future needs for high flux heat removal in advanced military electronics systems. The results are sorted by broad application categories: (1) commercial digital systems, (2) military data processors, (3) power processors, and (4) radar and optical systems. For applications expected to be fielded in five to ten years, the outlook is for steady state flux levels of 30-50 W/sq cm for digital processors and several hundred W/sq cm for power control applications. In Phase 1, a trade study was conducted on emerging cooling technologies which could remove a steady state chip heat flux of 100 W/sq cm while holding chip junction temperature to 90 C. Constraints imposed on heat exchanger design, in order to reflect operation in a fighter aircraft environment, included a practical lower limit on coolant supply temperature, the preference for a nontoxic, nonflammable, and nonfreezing coolant, the need to minimize weight and volume, and operation in an accelerating environment. The trade study recommended the Compact High Intensity Cooler (CHIC) for design, fabrication, and test in the final two phases of this program.

  11. Radiative Flux Analysis

    DOE Data Explorer

    Long, Chuck [NOAA

    2008-05-14

    The Radiative Flux Analysis is a technique for using surface broadband radiation measurements for detecting periods of clear (i.e. cloudless) skies, and using the detected clear-sky data to fit functions which are then used to produce continuous clear-sky estimates. The clear-sky estimates and measurements are then used in various ways to infer cloud macrophysical properties.

  12. Muon and neutrino fluxes

    NASA Technical Reports Server (NTRS)

    Edwards, P. G.; Protheroe, R. J.

    1985-01-01

    The result of a new calculation of the atmospheric muon and neutrino fluxes and the energy spectrum of muon-neutrinos produced in individual extensive air showers (EAS) initiated by proton and gamma-ray primaries is reported. Also explained is the possibility of detecting atmospheric nu sub mu's due to gamma-rays from these sources.

  13. Incident meteoroid flux density

    NASA Technical Reports Server (NTRS)

    Badadjanov, P. B.; Bibarsov, R. SH.; Getman, V. S.; Kolmakov, V. M.

    1987-01-01

    Complex photographic and radar meteor observations were carried out. Using the available observational data, the density of incident flux of meteoroids was estimated over a wide mass range of 0.001 to 100 g. To avoid the influence of apparatus selectivity a special technique was applied. The main characteristics of this technique are given and discussed.

  14. Quantifying the dynamic evolution of individual arched magnetic flux tubes

    NASA Astrophysics Data System (ADS)

    Stenson, E. V.; Bellan, P. M.

    2012-12-01

    Highly dynamic arched ‘loops’ of plasma were created in the laboratory with a magnetized plasma gun. The magnetic structure of the loops was found to be consistent with that of an expanding flux tube subject to a kink instability. High-speed flows were found to transport plasma along the loop axis, from both footpoints toward the apex of the arched loop. Two complementary MHD models were used to explain the expansion and axial flows, both of which scale in proportion to a ‘toroidal Alfven speed’.

  15. Description of heat flux measurement methods used in hydrocarbon and propellant fuel fires at Sandia.

    SciTech Connect

    Nakos, James Thomas

    2010-12-01

    The purpose of this report is to describe the methods commonly used to measure heat flux in fire applications at Sandia National Laboratories in both hydrocarbon (JP-8 jet fuel, diesel fuel, etc.) and propellant fires. Because these environments are very severe, many commercially available heat flux gauges do not survive the test, so alternative methods had to be developed. Specially built sensors include 'calorimeters' that use a temperature measurement to infer heat flux by use of a model (heat balance on the sensing surface) or by using an inverse heat conduction method. These specialty-built sensors are made rugged so they will survive the environment, so are not optimally designed for ease of use or accuracy. Other methods include radiometers, co-axial thermocouples, directional flame thermometers (DFTs), Sandia 'heat flux gauges', transpiration radiometers, and transverse Seebeck coefficient heat flux gauges. Typical applications are described and pros and cons of each method are listed.

  16. IN-CORE FLUX SENSOR EVALUATIONS AT THE ATR CRITICAL FACILITY.

    SciTech Connect

    Troy Unruh; Benjamin Chase; Joy Rempe; David Nigg; George Imel; Jason Harris; Todd Sherman; Jean-Francois VIllard

    2014-12-01

    As part of an Idaho State University (ISU)–led Advanced Test Reactor (ATR) National Scientific User Facility (NSUF) collaborative project that includes Idaho National Laboratory (INL) and the French Alternative Energies and Atomic Energy Commission (CEA), flux detector evaluations were completed to compare their accuracy, response time, and longduration performance. Special fixturing, developed by INL, allows real-time flux detectors to be inserted into various Advanced Test Reactor Critical Facility (ATRC) core positions to perform lobe power measurements, axial flux profile measurements, and detector crosscalibrations. Detectors initially evaluated in this program included miniature fission chambers, specialized self-powered neutron detectors (SPNDs), and specially developed commercial SPNDs. Results from this program provide important insights related to flux detector accuracy and resolution for subsequent ATR and CEA experiments and yield new flux data required for benchmarking models in the ATR Life Extension Program (LEP) Modeling Update Project.

  17. 16,000-rpm Interior Permanent Magnet Reluctance Machine with Brushless Field Excitation

    SciTech Connect

    Hsu, J.S.; Burress, T.A.; Lee, S.T.; Wiles, R.H.; Coomer, C.L.; McKeever, J.W.; Adams, D.J.

    2007-10-31

    The reluctance interior permanent magnet (RIPM) motor is currently used by many leading auto manufacturers for hybrid vehicles. The power density for this type of motor is high compared with that of induction motors and switched reluctance motors. The primary drawback of the RIPM motor is the permanent magnet (PM) because during high-speed operation, the fixed PM produces a huge back electromotive force (emf) that must be reduced before the current will pass through the stator windings. This reduction in back-emf is accomplished with a significant direct-axis (d-axis) demagnetization current, which opposes the PM's flux to reduce the flux seen by the stator wires. This may lower the power factor and efficiency of the motor and raise the requirement on the alternate current (ac) power supply; consequently, bigger inverter switching components, thicker motor winding conductors, and heavier cables are required. The direct current (dc) link capacitor is also affected when it must accommodate heavier harmonic currents. It is commonly agreed that, for synchronous machines, the power factor can be optimized by varying the field excitation to minimize the current. The field produced by the PM is fixed and cannot be adjusted. What can be adjusted is reactive current to the d-axis of the stator winding, which consumes reactive power but does not always help to improve the power factor. The objective of this project is to avoid the primary drawbacks of the RIPM motor by introducing brushless field excitation (BFE). This offers both high torque per ampere (A) per core length at low speed by using flux, which is enhanced by increasing current to a fixed excitation coil, and flux, which is weakened at high speed by reducing current to the excitation coil. If field weakening is used, the dc/dc boost converter used in a conventional RIPM motor may be eliminated to reduce system costs. However, BFE supports a drive system with a dc/dc boost converter, because it can further extend

  18. Design comparison of single phase outer and inner-rotor hybrid excitation flux switching motor for hybrid electric vehicles

    NASA Astrophysics Data System (ADS)

    Mazlan, Mohamed Mubin Aizat; Sulaiman, Erwan; Husin, Zhafir Aizat; Othman, Syed Muhammad Naufal Syed; Khan, Faisal

    2015-05-01

    In hybrid excitation machines (HEMs), there are two main flux sources which are permanent magnet (PM) and field excitation coil (FEC). These HEMs have better features when compared with the interior permanent magnet synchronous machines (IPMSM) used in conventional hybrid electric vehicles (HEVs). Since all flux sources including PM, FEC and armature coils are located on the stator core, the rotor becomes a single piece structure similar with switch reluctance machine (SRM). The combined flux generated by PM and FEC established more excitation fluxes that are required to produce much higher torque of the motor. In addition, variable DC FEC can control the flux capabilities of the motor, thus the machine can be applied for high-speed motor drive system. In this paper, the comparisons of single-phase 8S-4P outer and inner rotor hybrid excitation flux switching machine (HEFSM) are presented. Initially, design procedures of the HEFSM including parts drawing, materials and conditions setting, and properties setting are explained. Flux comparisons analysis is performed to investigate the flux capabilities at various current densities. Then the flux linkages of PM with DC FEC of various DC FEC current densities are examined. Finally torque performances are analyzed at various armature and FEC current densities for both designs. As a result, the outer-rotor HEFSM has higher flux linkage of PM with DC FEC and higher average torque of approximately 10% when compared with inner-rotor HEFSM.

  19. Intense source of cold cesium atoms based on a two-dimensional magneto–optical trap with independent axial cooling and pushing

    NASA Astrophysics Data System (ADS)

    Jia-Qiang, Huang; Xue-Shu, Yan; Chen-Fei, Wu; Jian-Wei, Zhang; Li-Jun, Wang

    2016-06-01

    We report our studies on an intense source of cold cesium atoms based on a two-dimensional (2D) magneto–optical trap (MOT) with independent axial cooling and pushing. The new-designed source, proposed as 2D-HP MOT, uses hollow laser beams for axial cooling and a thin pushing laser beam to extract a cold atomic beam. With the independent pushing beam, the atomic flux can be substantially optimized. The total atomic flux maximum obtained in the 2D-HP MOT is 4.02 × 1010 atoms/s, increased by 60 percent compared to the traditional 2D+ MOT in our experiment. Moreover, with the pushing power 10 μW and detuning 0Γ, the 2D-HP MOT can generate a rather intense atomic beam with the concomitant light shift suppressed by a factor of 20. The axial velocity distribution of the cold cesium beams centers at 6.8 m/s with an FMHW of about 2.8 m/s. The dependences of the atomic flux on the pushing power and detuning are studied in detail. The experimental results are in good agreement with the theoretical model. Project supported by the National Natural Science Foundation of China (Grant No. 11304177).

  20. Intense source of cold cesium atoms based on a two-dimensional magneto-optical trap with independent axial cooling and pushing

    NASA Astrophysics Data System (ADS)

    Jia-Qiang, Huang; Xue-Shu, Yan; Chen-Fei, Wu; Jian-Wei, Zhang; Li-Jun, Wang

    2016-06-01

    We report our studies on an intense source of cold cesium atoms based on a two-dimensional (2D) magneto-optical trap (MOT) with independent axial cooling and pushing. The new-designed source, proposed as 2D-HP MOT, uses hollow laser beams for axial cooling and a thin pushing laser beam to extract a cold atomic beam. With the independent pushing beam, the atomic flux can be substantially optimized. The total atomic flux maximum obtained in the 2D-HP MOT is 4.02 × 1010 atoms/s, increased by 60 percent compared to the traditional 2D+ MOT in our experiment. Moreover, with the pushing power 10 μW and detuning 0Γ, the 2D-HP MOT can generate a rather intense atomic beam with the concomitant light shift suppressed by a factor of 20. The axial velocity distribution of the cold cesium beams centers at 6.8 m/s with an FMHW of about 2.8 m/s. The dependences of the atomic flux on the pushing power and detuning are studied in detail. The experimental results are in good agreement with the theoretical model. Project supported by the National Natural Science Foundation of China (Grant No. 11304177).