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Sample records for coil suspension system

  1. Change in the coil distribution of electrodynamic suspension system

    NASA Technical Reports Server (NTRS)

    Tanaka, Hisashi

    1992-01-01

    At the Miyazaki Maglev Test Center, the initial test runs were completed using a system design that required the superconducting coils to be parallel with the ground levitation coils. Recently, the coil distribution was changed to a system such that the two types of coils were perpendicular to each other. Further system changes will lead to the construction of a side wall levitation system. It is hoped that the development will culminate in a system whereby a superconducting coil will maintain all the functions: levitation, propulsion, and guidance.

  2. Magnetic damping forces in figure-eight-shaped null-flux coil suspension systems

    SciTech Connect

    He, Jianliang; Coffey, H.

    1997-08-01

    This paper discusses magnetic damping forces in figure-eight-shaped null-flux coil suspension systems, focusing on the Holloman maglev rocket system. The paper also discusses simulating the damping plate, which is attached to the superconducting magnet by two short-circuited loop coils in the guideway. Closed-form formulas for the magnetic damping coefficient as functions of heave-and-sway displacements are derived by using a dynamic circuit model. These formulas are useful for dynamic stability studies.

  3. Electrodynamic forces of the cross-connected figure-eight null-flux coil suspension system

    SciTech Connect

    He, J.L.; Rote, D.M.; Coffey, H.T.

    1993-01-01

    This paper analyzes the cross-connected figure-eight null-flux coil suspension system for maglev vehicles on the basis of dynamic circuit theory. The equivalent circuits and general magnetic force expressions for the system are developed. Simple analytical formulas for the magnetic force partitions on the basis of harmonic approximation are presented, and numerical results are also included.

  4. Electrodynamic forces of the cross-connected figure-eight null-flux coil suspension system

    SciTech Connect

    He, J.L.; Rote, D.M.; Coffey, H.T.

    1993-06-01

    This paper analyzes the cross-connected figure-eight null-flux coil suspension system for maglev vehicles on the basis of dynamic circuit theory. The equivalent circuits and general magnetic force expressions for the system are developed. Simple analytical formulas for the magnetic force partitions on the basis of harmonic approximation are presented, and numerical results are also included.

  5. Study on figure-eight-shaped coil electrodynamic suspension magnetic levitation systems without cross-connection

    SciTech Connect

    Ribani, P.L.; Urbano, N.

    2000-01-01

    Two figure-eight-shaped coils for electrodynamic suspension (EDS) magnetic levitation (MAGLEV) systems without cross-connection are proposed and analyzed. The guideway coils are positioned under the MAGLEV vehicle; they are parallel to the horizontal plane. The interaction of a magnetic module on the vehicle, composed of three or four superconducting (SC) coils, with a guideway module, comprised of two figure-eight coils, is studied by means of the dynamic circuit theory. The currents in the SC coils are supposed to be constant in time while they move as a rigid body, with a constant velocity. Some results are presented and compared with those for a standard side-wall cross-connected system.

  6. Some Aspects of an Air-Core Single-Coil Magnetic Suspension System

    NASA Technical Reports Server (NTRS)

    Hamlet, Irvin L.; Kilgore, Robert A.

    1966-01-01

    This paper presents some of the technical aspects in the development at the Langley Research Center of an air-cove, dual-wound, single-coil, magnetic-suspension system with one-dimensional control. Overall electrical system design features and techniques are discussed in addition to the problems of control and stability. Special treatment is given to the operation of a dual-wound, high-current support coil which provides the bias fields and superimposed modulated field. Other designs features include a six-phase, solid-state power stage for modulation of the relatively large magnitude control current, and an associated six-phase trigger circuit.

  7. Some Aspects of an Air-Core Single-Coil Magnetic Suspension System

    NASA Technical Reports Server (NTRS)

    Hamlet, Irvin L.; Kilgore, Robert A.

    1966-01-01

    This paper presents some of the technical aspects in the development at the Langley Research Center of an air-cove, dual-wound, single-coil, magnetic-suspension system with one-dimensional control. Overall electrical system design features and techniques are discussed in addition to the problems of control and stability. Special treatment is given to the operation of a dual-wound, high-current support coil which provides the bias fields and superimposed modulated field. Other designs features include a six-phase, solid-state power stage for modulation of the relatively large magnitude control current, and an associated six-phase trigger circuit.

  8. Large gap magnetic suspension system

    NASA Technical Reports Server (NTRS)

    Abdelsalam, Moustafa K.; Eyssa, Y. M.

    1991-01-01

    The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system.

  9. Coil system for plasmoid thruster

    NASA Technical Reports Server (NTRS)

    Eskridge, Richard H. (Inventor); Lee, Michael H. (Inventor); Martin, Adam K. (Inventor); Fimognari, Peter J. (Inventor)

    2010-01-01

    A coil system for a plasmoid thruster includes a bias coil, a drive coil and field coils. The bias and drive coils are interleaved with one another as they are helically wound about a conical region. A first field coil defines a first passage at one end of the conical region, and is connected in series with the bias coil. A second field coil defines a second passage at an opposing end of the conical region, and is connected in series with the bias coil.

  10. Study of Japanese electrodynamic-suspension maglev systems

    SciTech Connect

    He, J.L.; Rote, D.M.; Coffey, H.T.

    1994-04-01

    This report presents the results of a study of the Japanese MLU magnetic-levitation (maglev) system. The development of the MLU system is reviewed, and the dynamic circuit model then is introduced and applied to the figure-eight-shaped null-flux coil suspension system. Three different types of figure-eight-shaped null-flux suspension systems are discussed in detail: (1) the figure-eight-shaped null-flux coil suspension system without cross-connection; (2) the combined suspension and guidance system; and (3) the combined propulsion, levitation, and guidance system. The electrodynamic-suspension maglev systems developed in Japan seem to be very promising and could result in a commercial application in the near future.

  11. Magnetic suspension and balance system study

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

    1984-01-01

    A compact design for a superconducting magnetic suspension and balance system is developed for a 8 ft. x 8 ft. transonic wind tunnel. The main features of the design are: a compact superconducting solenoid in the suspended airplane model; permanent magnet wings; one common liquid helium dewar for all superconducting coils; efficient new race track coils for roll torques; use of established 11 kA cryostable AC conductor; acceptable AC losses during 10 Hz control even with all steel structure; and a 560 liter/hour helium liquefier. Considerable design simplicity, reduced magnet weights, and reduced heat leak results from using one common dewar which eliminates most heavy steel structure between coils and the suspended model. Operational availability is thought to approach 100% for such magnet systems. The weight and cost of the magnet system is approximately one-third that of previous less compact designs.

  12. Automobile suspension system

    SciTech Connect

    Kumagai, N.; Tatemoto, M.; Oshima, S.; Maruyama, M.; Wada, S.; Shimomura, S.

    1986-11-25

    A suspension system is described for an automobile comprising a suspension having variable characteristics changeable according to an operating condition of the vehicle, and at least one of a vehicle speed sensor means for detecting the speed of the vehicle. It also comprises a steering wheel sensor means for detecting the steering condition of the vehicle's steering wheel, a vehicle height sensor means for detecting the height of the vehicle body relative to the vehicle wheel or the vehicle wheel axle and corresponding to a plurality of classified height ranges, and an acceleration sensor means for detecting the acceleration of the vehicle. The system further comprises: a first means for detecting commencement of the turning movement of the vehicle on the basis of at least one of the output signals from the vehicle speed sensor means, the steering wheel sensor means, the vehicle height sensor means, and the acceleration sensor means. The first means is also for changing the suspension characteristic to a first value representing a hard condition; and a second means for detecting completion of the turning movement of the vehicle on the basis of at least one of the output signals from the vehicle speed sensor means, the steering wheel sensor means, the vehicle height sensor means, and the acceleration sensor means. The second means is also for changing the suspension characteristic to a second value representing a soft condition.

  13. Magnetic suspension and balance system advanced study

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

    1985-01-01

    An improved compact design for a superconducting magnetic suspension and balance system for an 8 ft. x 8 ft. transonic wind tunnel is developed. The original design of an MSBS in NASA Cr-3802 utilized 14 external superconductive coils and a superconductive solenoid in the airplane test model suspended in a wind tunnel. The improvements are in the following areas: test model solenoid options, dynamic force limits on the model, magnet cooling options, structure and cryogenic designs, power supply specifications, and cost and performance evaluations. The improvements are: MSBS cost reduction of 28%, weight; reduction of 43%, magnet system ampere-meter reduction of 38%, helium liquifier capacity reduction by 33%, magnet system stored energy reduction by 55%, AC loss to liquid helium reduced by 76%, system power supply reduced by 68%, test coil pole strength increased by 19%, wing magnetization increased by 40%, and control frequency limit increased by 200% from 10 Hz to 30 Hz. The improvements are due to: magnetic holmium coil forms in the test model, better rare earth permanent magnets in the wings, fiberglass-epoxy structure replacing stainless steel, better coil configuration, and new saddle roll coil design.

  14. Controls of maglev suspension systems

    SciTech Connect

    Cai, Y.; Zhu, S.; Chen, S.S.; Rote, D.M.

    1993-06-01

    This study investigates alternative control designs of maglev vehicle suspension systems. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. A one-dimensional vehicle with two degrees of freedom, to simulate the German Transrapid Maglev System, is used for suspension control designs. The transient and frequency responses of suspension systems and PSDs of vehicle accelerations are calculated to evaluate different control designs. The results show that active and semi-active control designs indeed improve the response of vehicle and provide an acceptable ride comfort for maglev systems.

  15. Suspension Bridge Structural Systems: Cable Suspension & Anchorage; Warren Stiffening ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Suspension Bridge Structural Systems: Cable Suspension & Anchorage; Warren Stiffening Truss; Upper & Lower Decks; Assembled System - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  16. Tubing suspension system

    SciTech Connect

    Berner, P. C.; Brickman, E. L.

    1985-12-31

    A tubing suspension system for undersea well production operations employs a nonoriented tubing hanger having an inner body for supporting a tubing string and a landing collar for supporting the tubing hanger on a wellhead casing. The tubing hanger includes three co-operating concentric sleeve assemblies which are employed to lock and seal the tubing hanger to the wellhead housing. The outer sleeve assembly includes a locking actuator and a dual seal assembly and is separately retrievable from the remainder of the hanger assmebly. A nonorienting hydraulic set running tool is employed to run the tubing hanger, set the seals, lock the tubing hanger to the wellhead casing, retrieve either the outer sleeve assembly or the entire tubing hanger. The running tool includes a hydraulically controlled actuating sleeve which carries a latch dog assembly which locks with the tubing hanger.

  17. Modular coils: a promising toroidal-reactor-coil system

    SciTech Connect

    Chu, T.K.; Furth, H.P.; Johnson, J.L.; Ludescher, C.; Weimer, K.E.

    1981-04-01

    The concept of modular coils originated from a need to find reactor-relevant stellarator windings, but its usefulness can be extended to provide an externally applied, additional rotational transform in tokamaks. Considerations of (1) basic principles of modular coils, (2) types of coils, (3) types of configurations (general, helically symmetric, helically asymmetric, with magnetic well, with magnetic hill), (4) types of rotational transform profile, and (5) structure and origin of ripples are given. These results show that modular coils can offer a wide range of vacuum magnetic field configurations, some of which cannot be obtained with the classical stellarator or torsatron coil configuration.

  18. Articulated suspension system

    NASA Technical Reports Server (NTRS)

    Bickler, Donald B. (Inventor)

    1989-01-01

    The invention provides a rough terrain vehicle which maintains a substantially constant weight, and therefore traction, on all wheels, despite one wheel moving considerably higher or lower than the others, while avoiding a very soft spring suspension. The vehicle includes a chassis or body to be supported and a pair of side suspensions at either side of the body. In a six wheel vehicle, each side suspension includes a middle wheel, and front and rear linkages respectively coupling the front and rear wheels to the middle wheel. A body link pivotally connects the front and rear linkages together, with the middle of the body link rising or falling by only a fraction of the rise or fall of any of the three wheels. The body link pivotally supports the middle of the length of the body. A transverse suspension for suspending the end of the body on the side suspensions includes a middle part pivotally connected to the body about a longitudinal axis and opposite ends each pivotally connected to one of the side suspensions along at least a longitudinal axis.

  19. Automotive suspension system

    SciTech Connect

    Kanai, S.

    1986-11-11

    This patent describes an automotive suspension system comprising a wheel support for supporting a wheel, and a wheel supporting member for connecting the wheel support to the vehicle body. The wheel supporting member includes front and rear resilient supporting means spaced from each other by a predetermined distance in the longitudinal direction of the vehicle body and the direction of the toe of the wheel is adapted to be changed according to deformation of the front and rear resilient supporting means. The load-deformation characteristics of the front and rear resilient supporting means are selected so that the ratio of the amount of deformation of the front resilient supporting means for a given load to that of the rear resilient supporting means for the same load changes according to the magnitude of external side forces acting on the wheel, thereby changing the steering characteristics according to the magnitude of external force. The deformation is that in right and left or width directions of the vehicle body caused by the side forces.

  20. Superconducting Electromagnetic Suspension (EMS) system for Grumman Maglev concept

    NASA Technical Reports Server (NTRS)

    Kalsi, Swarn S.

    1994-01-01

    The Grumman developed Electromagnetic Suspension (EMS) Maglev system has the following key characteristics: a large operating airgap--40 mm; levitation at all speeds; both high speed and low speed applications; no deleterious effects on SC coils at low vehicle speeds; low magnetic field at the SC coil--less than 0.35 T; no need to use non-magnetic/non-metallic rebar in the guideway structure; low magnetic field in passenger cabin--approximately 1 G; low forces on the SC coil; employs state-of-the-art NbTi wire; no need for an active magnet quench protection system; and lower weight than a magnet system with copper coils. The EMS Maglev described in this paper does not require development of any new technologies. The system could be built with the existing SC magnet technology.

  1. A Mechanical Coil Insertion System for Endovascular Coil Embolization of Intracranial Aneurysms

    PubMed Central

    Haraguchi, K.; Miyachi, S.; Matsubara, N.; Nagano, Y.; Yamada, H.; Marui, N.; Sano, A.; Fujimoto, H.; Izumi, T.; Yamanouchi, T.; Asai, T.; Wakabayashi, T.

    2013-01-01

    Summary Like other fields of medicine, robotics and mechanization might be introduced into endovascular coil embolization of intracranial aneurysms for effective treatment. We have already reported that coil insertion force could be smaller and more stable when the coil delivery wire is driven mechanically at a constant speed. Another background is the difficulty in synchronizing operators' minds and hands when two operators control the microcatheter and the coil respectively. We have therefore developed a mechanical coil insertion system enabling a single operator to insert coils at a fixed speed while controlling the microcatheter. Using our new system, the operator manipulated the microcatheter with both hands and drove the coil using foot switches simultaneously. A delivery wire force sensor previously reported was used concurrently, allowing the operator to detect excessive stress on the wire. In vitro coil embolization was performed using three methods: simple mechanical advance of the coil; simple mechanical advance of the coil with microcatheter control; and driving (forward and backward) of the coil using foot switches in addition to microcatheter control. The system worked without any problems, and did not interfere with any procedures. In experimental coil embolization, delivery wire control using the foot switches as well as microcatheter manipulation helped to achieve successful insertion of coils. This system could offer the possibility of developing safer and more efficient coil embolization. Although we aim at total mechanization and automation of procedures in the future, microcatheter manipulation and synchronized delivery wire control are still indispensable using this system. PMID:23693038

  2. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    DOEpatents

    Rote, Donald M.; He, Jianliang; Johnson, Larry R.

    1994-01-01

    A propulsion and stabilization system comprising a series of FIG. 8 coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the FIG. 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

  3. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    DOEpatents

    Rote, D.M.; He, J.; Johnson, L.R.

    1994-01-04

    A propulsion and stabilization system are described comprising a series of coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance, and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension. 8 figures.

  4. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    DOEpatents

    Rote, D.M.; He, Jianliang; Johnson, L.R.

    1992-01-01

    This report discusses a propulsion and stabilization system comprising a series of figure 8 coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the figure 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

  5. 49 CFR 238.427 - Suspension system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Suspension system. 238.427 Section 238.427... Equipment § 238.427 Suspension system. (a) General requirements. (1) Suspension systems shall be designed to... equipment. (2) Passenger equipment shall meet the safety performance standards for suspension systems...

  6. 49 CFR 238.427 - Suspension system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Suspension system. 238.427 Section 238.427... Equipment § 238.427 Suspension system. (a) General requirements. (1) Suspension systems shall be designed to... equipment. (2) All passenger equipment shall meet the safety performance standards for suspension systems...

  7. Superconducting Coil Winding Machine Control System

    SciTech Connect

    Nogiec, J. M.; Kotelnikov, S.; Makulski, A.; Walbridge, D.; Trombly-Freytag, K.

    2016-10-05

    The Spirex coil winding machine is used at Fermilab to build coils for superconducting magnets. Recently this ma-chine was equipped with a new control system, which al-lows operation from both a computer and a portable remote control unit. This control system is distributed between three layers, implemented on a PC, real-time target, and FPGA, providing respectively HMI, operational logic and direct controls. The system controls motion of all mechan-ical components and regulates the cable tension. Safety is ensured by a failsafe, redundant system.

  8. Stability considerations for magnetic suspension systems using electromagnets mounted in a planar array

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.; Britcher, Colin P.

    1991-01-01

    Mathematical models of a 5, 6, 7, and 8 coil large gap magnetic suspension system (MSDS) are presented. Some of the topics covered include: force and torque equations, reduction of state-space form, natural modes, origins of modes, effect of rotation in azimuth (yaw), future work, and n-coil ring conclusions.

  9. Mathematical Analysis of a Large-Gap Electromagnetic Suspension System

    NASA Astrophysics Data System (ADS)

    Jump, Addison Benjamin

    In a form of controlled electromagnetic suspension, a permanent magnetic is levitated by a magnetic field; the field is produced by electrical currents passing through coils. These currents are the control input. In a Large -Gap system the coils are at some distance from the suspended body; in general, there is no closed form expression relating the currents to the flux at the point of the suspended body. Thus, in the general case, it is not possible to establish control-theoretic results for this kind of Large -Gap suspension system. It is shown, however, that if the coil placement configuration exhibits a particular cylindrically symmetric structure, expressions can be found relating the coil positions to the flux. These expressions are used to show the existence of a unique equilibrium point and controllability, in five dimensions of control, for a generic form of Large-Gap system. The results are shown to remain true if the suspended body is rotated about a particular axis. Closed form expressions are found for the currents required to suspend the body at these variable orientations. An inequality between difference classes of experimental inputs is shown to be a necessary condition for suspension of the body. It is demonstrated that the addition of coils to the system cannot lead to six dimensions of controllability. Let the system be given by the standard control equationdot x=Ax+Bu Closed form expressions are found for the eigenvalues of A. In the course of proving that some coil placement restrictions may be relaxed, B is shown to be related to the Vandermonde matrix.

  10. Design of the coolant system for the Large Coil Test Facility pulse coils

    SciTech Connect

    Bridgman, C.; Ryan, T.L.

    1983-01-01

    The pulse coils will be a part of the Large Coil Test Facility in Oak Ridge, Tennessee, which is designed to test six large tokamak-type superconducting coils. The pulse coil set consists of two resistive coaxial solenoid coils, mounted so that their magnetic axis is perpendicular to the toroidal field lines of the test coil. The pulse coils provide transient vertical fields at test coil locations to simulate the pulsed vertical fields present in tokamak devices. The pulse coils are designed to be pulsed for 30 s every 150 s, which results in a Joule heating of 116 kW per coil. In order to provide this capability, the pulse coil coolant system is required to deliver 6.3 L/s (100 gpm) of subcooled liquid nitrogen at 10-atm absolute pressure. The coolant system can also cool down each pulse coil from room temperature to liquid nitrogen temperature. This paper provides details of the pumping and heat exchange equipment designed for the coolant system and of the associated instrumentation and controls.

  11. Measuring the orthogonality error of coil systems

    USGS Publications Warehouse

    Heilig, B.; Csontos, A.; Pajunpää, K.; White, Tim; St. Louis, B.; Calp, D.

    2012-01-01

    Recently, a simple method was proposed for the determination of pitch angle between two coil axes by means of a total field magnetometer. The method is applicable when the homogeneous volume in the centre of the coil system is large enough to accommodate the total field sensor. Orthogonality of calibration coil systems used for calibrating vector magnetometers can be attained by this procedure. In addition, the method can be easily automated and applied to the calibration of delta inclination–delta declination (dIdD) magnetometers. The method was tested by several independent research groups, having a variety of test equipment, and located at differing geomagnetic observatories, including: Nurmijärvi, Finland; Hermanus, South Africa; Ottawa, Canada; Tihany, Hungary. This paper summarizes the test results, and discusses the advantages and limitations of the method.

  12. 49 CFR 393.207 - Suspension systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... pressure regulator valve shall not allow air into the suspension system until at least 55 psi is in the... pressure. (g) Air suspension exhaust controls. The air suspension exhaust controls must not have the... 49 Transportation 5 2011-10-01 2011-10-01 false Suspension systems. 393.207 Section 393.207...

  13. 49 CFR 570.8 - Suspension systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Suspension systems. 570.8 Section 570.8... Pounds or Less § 570.8 Suspension systems. (a) Suspension condition. Ball joint seals shall not be cut or... out from or missing from suspension joints. Radius rods shall not be missing or damaged....

  14. Airfoil flutter model suspension system

    NASA Technical Reports Server (NTRS)

    Reed, Wilmer H. (Inventor)

    1987-01-01

    A wind tunnel suspension system for testing flutter models under various loads and at various angles of attack is described. The invention comprises a mounting bracket assembly affixing the suspension system to the wind tunnel, a drag-link assembly and a compound spring arrangement comprises a plunge spring working in opposition to a compressive spring so as to provide a high stiffness to trim out steady state loads and simultaneously a low stiffness to dynamic loads. By this arrangement an airfoil may be tested for oscillatory response in both plunge and pitch modes while being held under high lifting loads in a wind tunnel.

  15. Intra-coil interactions in split gradient coils in a hybrid MRI-LINAC system

    NASA Astrophysics Data System (ADS)

    Tang, Fangfang; Freschi, Fabio; Sanchez Lopez, Hector; Repetto, Maurizio; Liu, Feng; Crozier, Stuart

    2016-04-01

    An MRI-LINAC system combines a magnetic resonance imaging (MRI) system with a medical linear accelerator (LINAC) to provide image-guided radiotherapy for targeting tumors in real-time. In an MRI-LINAC system, a set of split gradient coils is employed to produce orthogonal gradient fields for spatial signal encoding. Owing to this unconventional gradient configuration, eddy currents induced by switching gradient coils on and off may be of particular concern. It is expected that strong intra-coil interactions in the set will be present due to the constrained return paths, leading to potential degradation of the gradient field linearity and image distortion. In this study, a series of gradient coils with different track widths have been designed and analyzed to investigate the electromagnetic interactions between coils in a split gradient set. A driving current, with frequencies from 100 Hz to 10 kHz, was applied to study the inductive coupling effects with respect to conductor geometry and operating frequency. It was found that the eddy currents induced in the un-energized coils (hereby-referred to as passive coils) positively correlated with track width and frequency. The magnetic field induced by the eddy currents in the passive coils with wide tracks was several times larger than that induced by eddy currents in the cold shield of cryostat. The power loss in the passive coils increased with the track width. Therefore, intra-coil interactions should be included in the coil design and analysis process.

  16. Designed Coiled-Coil Peptides Inhibit the Type Three Secretion System of Enteropathogenic Escherichia coli

    PubMed Central

    Larzábal, Mariano; Mercado, Elsa C.; Vilte, Daniel A.; Salazar-González, Hector; Cataldi, Angel; Navarro-Garcia, Fernando

    2010-01-01

    Background Enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are two categories of E. coli strains associated with human disease. A major virulence factor of both pathotypes is the expression of a type three secretion system (TTSS), responsible for their ability to adhere to gut mucosa causing a characteristic attaching and effacing lesion (A/E). The TTSS translocates effector proteins directly into the host cell that subvert mammalian cell biochemistry. Methods/Principal Findings We examined synthetic peptides designed to inhibit the TTSS. CoilA and CoilB peptides, both representing coiled-coil regions of the translocator protein EspA, and CoilD peptide, corresponding to a coiled–coil region of the needle protein EscF, were effective in inhibiting the TTSS dependent hemolysis of red blood cells by the EPEC E2348/69 strain. CoilA and CoilB peptides also reduced the formation of actin pedestals by the same strain in HEp-2 cells and impaired the TTSS-mediated protein translocation into the epithelial cell. Interestingly, CoilA and CoilB were able to block EspA assembly, destabilizing the TTSS and thereby Tir translocation. This blockage of EspA polymerization by CoilA or CoilB peptides, also inhibited the correct delivery of EspB and EspD as detected by immunoblotting. Interestingly, electron microscopy of bacteria incubated with the CoilA peptide showed a reduction of the length of EspA filaments. Conclusions Our data indicate that coiled-coil peptides can prevent the assembly and thus the functionality of the TTSS apparatus and suggest that these peptides could provide an attractive tool to block EPEC and EHEC pathogenesis. PMID:20140230

  17. Magnetic suspension and balance system advanced study, phase 2

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Abdelsalam, M. K.; Eyssa, Y. M.; Mcintosh, G. E.

    1990-01-01

    The design improvements for the system encompass 14 or 18 external superconductive coils mounted on a 8 x 8 foot wind tunnel, a superconductive model core magnet on a holmium mandrel to fit an F-16 model, model wings of permanent magnet material Nd2Fe14B, and fiber glass epoxy structure. The Magnetic Suspension and Balance System (MSBS) advanced design is confirmed by the successful construction and test of a full size superconductive model core solenoid with holmium mandrel. The solenoid is 75 cm long and 12.6 cm in diameter and produces 6.1 tesla for a hold time of 47 minutes. An integrated coil system design of a new compact configuration without specific coils for roll or pitch shows promise of simplicity; magnet reductions of 30 percent compared to the most recent 1985 design are possible.

  18. Design description of the Large Coil Test Facility pulse-coil support and transport system

    SciTech Connect

    Queen, C.C.

    1981-01-01

    In order to simulate the transient fields which would be imposed on superconducting toroidal field coils in an operating tokamak reactor, the Large Coil Test Facility (LCTF) test stand includes a set of pulse coils. This set of pulse coils is designed to be moved from one test location to another within the LCTF vacuum vessel while the vessel is operating under vacuum and the test stand and test coils are at an operating temperature of 4.2K. This operating environment and the extremely high magnetic loads have necessitated some unique design features for the pulse coil support and transport system. The support structure for the pulse coil must react high overturning moments and axial loads induced on the pulse coil by the interaction of the pulse field with the field generated by the large test coils. These loads are reacted into the test stand support structure or spider frame by an arrangement of six pedestals and a support beam. In order to move the pulse coil set from one test location to another, the support beam containing the pulse coils must be driven across rollers mounted on the pedestals, then clamped securely to react the loads. Because these operations must be performed in a vacuum environment at cryogenic tmperature, special consideration was given to component design.

  19. Coil system for a mirror-based hybrid reactor

    SciTech Connect

    Hagnestal, A.; Agren, O.; Moiseenko, V. E.

    2012-06-19

    Two different superconducting coil systems for the SFLM Hybrid study - a quadrupolar mirror based fusion-fission reactor study - are presented. One coil system is for a magnetic field with 2 T at the midplane and a mirror ratio of four. This coil set consists of semiplanar coils in two layers. The alternative coil system is for a downscaled magnetic field of 1.25 T at the midplane and a mirror ratio of four, where a higher {beta} is required to achieve sufficient the neutron production. This coil set has one layer of twisted 3D coils. The 3D coils are expected to be considerably cheaper than the semiplanar, since NbTi superconductors can be used for most coils instead of Nb3Sn due to the lower magnetic field.

  20. Improved All-Terrain Suspension System

    NASA Technical Reports Server (NTRS)

    Bickler, Donald B.

    1994-01-01

    Redesigned suspension system for all-terrain vehicle exhibits enhanced ability to negotiate sand and rocks. Improved six-wheel suspension system includes only two links on each side. Bogie tends to pull rear wheels with it as it climbs. Designed for rover vehicle for exploration of Mars, also has potential application in off-road vehicles, military scout vehicles, robotic emergency vehicles, and toys. Predecessors of suspension system described in "Articulated Suspension Without Springs" (NPO-17354), "Four-Wheel Vehicle Suspension System" (NPO-17407), and "High-Clearance Six-Wheel Suspension" (NPO-17821).

  1. A wide linear range Eddy Current Displacement Sensor equipped with dual-coil probe applied in the Magnetic Suspension Flywheel.

    PubMed

    Fang, Jiancheng; Wen, Tong

    2012-01-01

    The Eddy Current Displacement Sensor (ECDS) is widely used in the Magnetic Suspension Flywheel (MSFW) to measure the tiny clearance between the rotor and the magnetic bearings. The linear range of the ECDS is determined by the diameter of its probe coil. Wide clearances must be measured in some new MSFWs recently designed for the different space missions, but the coil diameter is limited by some restrictions. In this paper, a multi-channel ECDS equipped with dual-coil probes is proposed to extend the linear range to satisfy the demands of such MSFWs. In order to determine the best configuration of the dual-coil probe, the quality factors of the potential types of the dual-coil probes, the induced eddy current and the magnetic intensity on the surface of the measuring object are compared with those of the conventional single-coil probe. The linear range of the ECDS equipped with the selected dual-coil probe is extended from 1.1 mm to 2.4 mm under the restrictions without adding any cost for additional compensation circuits or expensive coil materials. The effectiveness of the linear range extension ability and the dynamic response of the designed ECDS are confirmed by the testing and the applications in the MSFW.

  2. A Wide Linear Range Eddy Current Displacement Sensor Equipped with Dual-Coil Probe Applied in the Magnetic Suspension Flywheel

    PubMed Central

    Fang, Jiancheng; Wen, Tong

    2012-01-01

    The Eddy Current Displacement Sensor (ECDS) is widely used in the Magnetic Suspension Flywheel (MSFW) to measure the tiny clearance between the rotor and the magnetic bearings. The linear range of the ECDS is determined by the diameter of its probe coil. Wide clearances must be measured in some new MSFWs recently designed for the different space missions, but the coil diameter is limited by some restrictions. In this paper, a multi-channel ECDS equipped with dual-coil probes is proposed to extend the linear range to satisfy the demands of such MSFWs. In order to determine the best configuration of the dual-coil probe, the quality factors of the potential types of the dual-coil probes, the induced eddy current and the magnetic intensity on the surface of the measuring object are compared with those of the conventional single-coil probe. The linear range of the ECDS equipped with the selected dual-coil probe is extended from 1.1 mm to 2.4 mm under the restrictions without adding any cost for additional compensation circuits or expensive coil materials. The effectiveness of the linear range extension ability and the dynamic response of the designed ECDS are confirmed by the testing and the applications in the MSFW. PMID:23112623

  3. 49 CFR 393.207 - Suspension systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Suspension systems. 393.207 Section 393.207... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393.207 Suspension systems. (a) Axles. No axle positioning part shall be cracked, broken, loose or missing...

  4. Common Coil Magnet System for VLHC

    SciTech Connect

    Gupta, R.

    1999-02-12

    This paper introduces the common coil magnet system for the proposed very large hadron collider (VLHC). In this system, the high energy booster (HEB), the injector to VLHC, is integrated as the iron dominated low field aperture within the coldmass of the common coil magnet design introduced earlier. This 4-in-1 magnet concept for a 2-in-1 machine should provide a major cost reduction in building and operating VLHC. Moreover, the proposed design reduces the field quality problems associated with the large persistent currents in Nb{sub 3}Sn magnets. The paper also shows that the geometric field harmonics can be made small. In this preliminary magnetic design. the current dependence in harmonics is significant but not umnanageable.

  5. Four-Wheel Vehicle Suspension System

    NASA Technical Reports Server (NTRS)

    Bickler, Donald B.

    1990-01-01

    Four-wheel suspension system uses simple system of levers with no compliant components to provide three-point suspension of chassis of vehicle while maintaining four-point contact with uneven terrain. Provides stability against tipping of four-point rectangular base, without rocking contact to which rigid four-wheel frame susceptible. Similar to six-wheel suspension system described in "Articulated Suspension Without Springs" (NPO-17354).

  6. Theoretical and FEM analysis of suspension and propulsion system with HTS hybrid electromagnets in an EMS Maglev model

    NASA Astrophysics Data System (ADS)

    Chung, Y. D.; Lee, C. Y.; Jang, J. Y.; Yoon, Y. S.; Ko, T. K.

    2011-11-01

    We have been constructed a proto-type electromagnetic suspension (EMS) based maglev vehicle system. The maglev concept utilizes magnetic forces for noncontact suspension, guidance and propulsion. The suspension system with high temperature superconducting (HTS) hybrid electromagnet (EM) is composed of HTS coils and normal coils, which consume little power to keep large suspension gap. The magnetic forces realize to guide the vehicle, propel the vehicle along the guide-way and assist in braking action. The proto-type EMS-based Maglev model is designed to keep the suspension gap of 20 mm. This paper presents the theoretical analysis of the maglev vehicle based on the EMS model to obtain the designing parameters for levitation and propulsion forces. The magnetic field distributions of the electromagnetic forces with hybrid EM and propulsion stator coils are analyzed based on three dimension (3D) finite element method (FEM) analysis. From the simulation results, appropriately design parameters of the suspension, guidance and propulsion were obtained.

  7. Acoustic suspension system

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Wang, T. G. (Inventor)

    1983-01-01

    An acoustic levitation system is described, with single acoustic source and a small reflector to stably levitate a small object while the object is processed as by coating or heating it. The system includes a concave acoustic source which has locations on opposite sides of its axis that vibrate towards and away from a focal point to generate a converging acoustic field. A small reflector is located near the focal point, and preferably slightly beyond it, to create an intense acoustic field that stably supports a small object near the reflector. The reflector is located about one-half wavelength from the focal point and is concavely curved to a radius of curvature (L) of about one-half the wavelength, to stably support an object one-quarter wavelength (N) from the reflector.

  8. 49 CFR 570.8 - Suspension systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Suspension systems. 570.8 Section 570.8 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... Pounds or Less § 570.8 Suspension systems. (a) Suspension condition. Ball joint seals shall not be cut or...

  9. 49 CFR 570.61 - Suspension system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Suspension system. 570.61 Section 570.61 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... 10,000 Pounds § 570.61 Suspension system. (a) Suspension condition. Ball joint seals shall not be cut...

  10. 49 CFR 570.61 - Suspension system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Suspension system. 570.61 Section 570.61 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... 10,000 Pounds § 570.61 Suspension system. (a) Suspension condition. Ball joint seals shall not be cut...

  11. 49 CFR 570.8 - Suspension systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Suspension systems. 570.8 Section 570.8 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... Pounds or Less § 570.8 Suspension systems. (a) Suspension condition. Ball joint seals shall not be cut or...

  12. 49 CFR 570.8 - Suspension systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Suspension systems. 570.8 Section 570.8 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... Pounds or Less § 570.8 Suspension systems. (a) Suspension condition. Ball joint seals shall not be cut or...

  13. 49 CFR 570.61 - Suspension system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Suspension system. 570.61 Section 570.61 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... 10,000 Pounds § 570.61 Suspension system. (a) Suspension condition. Ball joint seals shall not be cut...

  14. Computation of magnetic suspension of maglev systems using dynamic circuit theory

    NASA Astrophysics Data System (ADS)

    He, J. L.; Rote, D. M.; Coffey, H. T.

    1992-05-01

    Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper.

  15. An iterative method for coil sensitivity estimation in multi-coil MRI systems.

    PubMed

    Ling, Qiang; Li, Zhaohui; Song, Kaikai; Li, Feng

    2014-12-01

    This paper presents an iterative coil sensitivity estimation method for multi-coil MRI systems. The proposed method works with coil images in the magnitude image domain. It determines a region of support (RoS), a region being composed of the same type of tissues, by a region growing algorithm, which makes use of both intensities and intensity gradients of pixels. By repeating this procedure, it can determine multiple regions of support, which together cover most of the concerned image area. The union of these regions of support provides a rough estimate of the sensitivity of each coil through dividing the intensities of pixels by the average intensity inside every region of support. The obtained rough coil sensitivity estimate is further approached with the product of multiple low-order polynomials, rather than a single one. The product of these polynomials provides a smooth estimate of the sensitivity of each coil. With the obtained sensitivities of coils, it can produce a better reconstructed image, which determines more correct regions of support and yields preciser estimates of the sensitivities of coils. In other words, the method can be iteratively implemented to improve the estimation performance. The proposed method was verified through both simulated data and clinical data from different body parts. The experimental results confirm the superiority of our method to some conventional methods.

  16. Attractive and repulsive magnetic suspension systems overview

    NASA Technical Reports Server (NTRS)

    Cope, David B.; Fontana, Richard R.

    1992-01-01

    Magnetic suspension systems can be used in a wide variety of applications. The decision of whether to use an attractive or repulsive suspension system for a particular application is a fundamental one which must be made during the design process. As an aid to the designer, we compare and contrast attractive and repulsive magnetic suspension systems and indicate whether and under what conditions one or the other system is preferred.

  17. Coupling suspension complex system optimization

    NASA Astrophysics Data System (ADS)

    English, Kenneth William

    The design of a complex product requires multiple analyses, many of which trade information. In some cases, some information is required before it is available, as a result an estimate must be made of that input for the analysis to proceed. Once the input becomes available, additional calculations must be made to ensure that the result of the analysis reflects the changed input. This iteration creates a considerable computational cost in the design process. This iteration may be eliminated through the reordering of the analyses, or through the temporary or permanent removal of the couplings between the system analyses. This elimination of couplings is termed system reduction. Until relatively recently, the trade of accuracy and efficiency that enables system reduction was only carried out in the context of local sensitivities, how much one analysis output impacts another output. Recent developments expanded this capability to include a system level measure of introduced error into the objective function and constraints, allowing the development of a selection subproblem that trades accuracy and efficiency in the system reduction context. The current state of the trade-off between accuracy and efficiency is far form complete. The initial subproblem formulation resulted in potentially destabilizing sets of couplings being selected, which could result in system analysis convergence errors. Additionally, the technique employed to select couplings for suspension is extremely limited in scope. The designer's intuition and experience had been eliminated from the selection process, replaced by a simple selection algorithm. First, the current coupling suspension problem is augmented, incorporating additional constraints to improve performance in system analysis stability, improved convergence characteristics, and more accurate error growth modeling. The second issue this dissertation addresses is the development of a methodology that allows a designer to interactively

  18. [Ultrafast MR sialography: comparison of two coil systems including an alternative surface coil].

    PubMed

    Weber, T F; Cramer, M C; Aldefeld, D; Weiss, F; Petersen, K U; Reitmeier, F; Jaehne, M; Adam, G; Habermann, C R

    2008-11-01

    To compare the visualization of salivary ducts by ultrafast magnetic resonance sialography (MR sialography) using an alternative surface coil and a conventional head-neck coil. In 11 healthy volunteers, ultrafast MR sialography (single shot turbo spin echo; acquisition time, 2.8 s) was performed before and after oral application of a sialogogue. Each subject received examinations with both a bilateral surface coil (SC) and a conventional head-neck coil (HNC). The depiction of parotideal and submandibular duct systems was graded from 1 to 5 (5 = poor) by four independent radiologists. ANOVA served for statistical analysis of duct rankings, and interobserver variability was determined by Intraclass Correlation Coefficient (ICC). With an excellent ICC of 0.96, both coil systems offered symmetric visualization of salivary ducts, and the image quality increased after oral application of sialogogue (p < 0.001). In total, the overall rating was worse for SC than for HNC (2.13 +/- 1.24 vs. 1.45 +/- 0.65, p < 0.001). SC was especially inferior in depiction of submandibular and extraglandular duct components compared to HNC (p < 0.001). Most notably due to the reduced visualization of extraglandular and submandibular ducts, the specific surface coil used in this study was inferior in image quality and does not constitute a reasonable alternative to conventional coil systems.

  19. Magnetic suspension systems for space applications

    NASA Technical Reports Server (NTRS)

    Havenhill, Douglas G.; Wolke, Patrick J.

    1991-01-01

    An overview of techniques is presented used in the described magnetic suspension systems. Also a review is presented of the systems already developed, which demonstrate the usefulness, applicability, and flight readiness of magnetic suspension to a broad range of payloads and environments. The following subject areas are covered: programs overview; key concepts; magnetic suspension as an isolator and as a pointer; pointing and isolation systems; magnetic actuator control techniques; and test data.

  20. 49 CFR 393.207 - Suspension systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... braking system. The vehicle shall be level (not tilting to the left or right). Air leakage shall not be... 49 Transportation 5 2013-10-01 2013-10-01 false Suspension systems. 393.207 Section 393.207... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems §...

  1. 49 CFR 393.207 - Suspension systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... braking system. The vehicle shall be level (not tilting to the left or right). Air leakage shall not be... 49 Transportation 5 2014-10-01 2014-10-01 false Suspension systems. 393.207 Section 393.207... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems §...

  2. 49 CFR 393.207 - Suspension systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... braking system. The vehicle shall be level (not tilting to the left or right). Air leakage shall not be... 49 Transportation 5 2012-10-01 2012-10-01 false Suspension systems. 393.207 Section 393.207... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems §...

  3. 49 CFR 238.227 - Suspension system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Suspension system. 238.227 Section 238.227 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Equipment § 238.227 Suspension system. On or after November 8, 1999— (a) All passenger equipment shall...

  4. 49 CFR 238.227 - Suspension system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Suspension system. 238.227 Section 238.227 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Equipment § 238.227 Suspension system. On or after November 8, 1999— (a) All passenger equipment shall...

  5. 49 CFR 238.227 - Suspension system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Suspension system. 238.227 Section 238.227 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Equipment § 238.227 Suspension system. On or after November 8, 1999— (a) All passenger equipment shall...

  6. Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching

    SciTech Connect

    He, J.; Rote, D.M.

    1994-12-31

    A stabilization and propulsion system comprising a series of loop-coils arranged in parallel rows wherein two rows form a magnetic rail. Levitation and lateral stability is provided when the induced field in the magnetic rails interacts with the superconducting magnets (SCM) mounted on the magnetic levitation vehicle. A multiphase propulsion system interconnects specific coils in a given magnetic rail and interacts with the SCM to produce a propulsion force to the vehicle.

  7. Advances in coiled-tubing operating systems

    SciTech Connect

    Sas-Jaworsky, A. II

    1997-06-01

    The expansion of coiled tubing (CT) applications into spooled flowlines, spooled completions, and CT drilling continues to grow at an accelerated rate. For many users within the oil and gas industry, the CT industry appears to be poised on the threshold of the next logical step in its evolution, the creation of a fully integrated operating system. However, for CT to evolve into such an operating system, the associated services must be robust and sufficiently reliable to support the needs of exploration, development drilling, completion, production management, and wellbore-retirement operations both technically and economically. The most critical hurdle to overcome in creating a CT-based operating system is a fundamental understanding of the operating scope and physical limitations of CT technology. The complete list of mechanisms required to advance CT into an operating system is large and complex. However, a few key issues (such as formal education, training, standardization, and increased levels of experience) can accelerate the transition. These factors are discussed.

  8. Mitigation of Intra-coil Eddy Currents in Split Gradient Coils in a Hybrid MRI-LINAC System.

    PubMed

    Tang, Fangfang; Freschi, Fabio; Repetto, Maurizio; Li, Yu; Liu, Feng; Crozier, Stuart

    2017-03-01

    The aim of this study is to mitigate intra-gradient coil eddy currents in a hybrid MRI-LINAC system. The tracks of the gradient coils are modified by cutting slits along the current flow direction. The electromagnetic model developed was first experimentally validated and then used to study the impacts of the slit conductors on the energized and surrounding coils. In this study, gradient coils were slit with different numbers of sub-tracks and driven by a current with frequencies ranging from 100 Hz to 10 kHz. The proposed configuration was assessed by evaluating a number of system parameters, such as the gradient magnetic field, the power loss generated in the surrounding unenergized coil (hereafter referred to as passive coils), and the performance of the energized coil. It was found that at a typical operating frequency of 1 kHz and compared with a conventional (no cut) split coil structure, the new coil pattern (with four slits) offered improved coil parameters. 1) The average power loss dissipated in the surrounding passive coil was significantly reduced by 85%, 2) the cuts largely reduced the secondary field generated by the eddy currents in the passive coil, which was reduced to about 4% of that produced by the uncut coil and, 3) the performance of the energized coil with slit tracks was significantly improved. Some typical gradient coil parameters, such as the figure of merit, efficiency (η), and η(2)/R (where η is the efficiency and R is the resistance), were improved by 8.0%, 11.9%, and 45.7%, respectively. The new slit coil structure is effective in mitigating intra-coil eddy current effects, which is an important issue in the MRI-LINAC system.

  9. A novel acoustically quiet coil for neonatal MRI system.

    PubMed

    Ireland, Christopher M; Giaquinto, Randy O; Loew, Wolfgang; Tkach, Jean A; Pratt, Ronald G; Kline-Fath, Beth M; Merhar, Stephanie L; Dumoulin, Charles L

    2015-08-01

    MRI acoustic exposure has the potential to elicit physiological distress and impact development in preterm and term infants. To mitigate this risk, a novel acoustically quiet coil was developed to reduce the sound pressure level experienced by neonates during MR procedures. The new coil has a conventional high-pass birdcage RF design, but is built on a framework of sound abating material. We evaluated the acoustic and MR imaging performance of the quiet coil and a conventional body coil on two small footprint NICU MRI systems. Sound pressure level and frequency response measurements were made for six standard clinical MR imaging protocols. The average sound pressure level, reported for all six imaging pulse sequences, was 82.2 dBA for the acoustically quiet coil, and 91.1 dBA for the conventional body coil. The sound pressure level values measured for the acoustically quiet coil were consistently lower, 9 dBA (range 6-10 dBA) quieter on average. The acoustic frequency response of the two coils showed a similar harmonic profile for all imaging sequences. However, the amplitude was lower for the quiet coil, by as much as 20 dBA.

  10. A novel acoustically quiet coil for neonatal MRI system

    PubMed Central

    Ireland, Christopher M.; Giaquinto, Randy O.; Loew, Wolfgang; Tkach, Jean A.; Pratt, Ronald G.; Kline-Fath, Beth M.; Merhar, Stephanie L.; Dumoulin, Charles L.

    2015-01-01

    MRI acoustic exposure has the potential to elicit physiological distress and impact development in preterm and term infants. To mitigate this risk, a novel acoustically quiet coil was developed to reduce the sound pressure level experienced by neonates during MR procedures. The new coil has a conventional high-pass birdcage RF design, but is built on a framework of sound abating material. We evaluated the acoustic and MR imaging performance of the quiet coil and a conventional body coil on two small footprint NICU MRI systems. Sound pressure level and frequency response measurements were made for six standard clinical MR imaging protocols. The average sound pressure level, reported for all six imaging pulse sequences, was 82.2 dBA for the acoustically quiet coil, and 91.1 dBA for the conventional body coil. The sound pressure level values measured for the acoustically quiet coil were consistently lower, 9 dBA (range 6-10 dBA) quieter on average. The acoustic frequency response of the two coils showed a similar harmonic profile for all imaging sequences. However, the amplitude was lower for the quiet coil, by as much as 20 dBA. PMID:26457072

  11. Magnetic suspension and balance systems (MSBSs)

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.; Kilgore, Robert A.

    1987-01-01

    The problems of wind tunnel testing are outlined, with attention given to the problems caused by mechanical support systems, such as support interference, dynamic-testing restrictions, and low productivity. The basic principles of magnetic suspension are highlighted, along with the history of magnetic suspension and balance systems. Roll control, size limitations, high angle of attack, reliability, position sensing, and calibration are discussed among the problems and limitations of the existing magnetic suspension and balance systems. Examples of the existing systems are presented, and design studies for future systems are outlined. Problems specific to large-scale magnetic suspension and balance systems, such as high model loads, requirements for high-power electromagnets, high-capacity power supplies, highly sophisticated control systems and position sensors, and high costs are assessed.

  12. NSTX-U Digital Coil Protection System Software Detailed Design

    SciTech Connect

    2014-06-01

    The National Spherical Torus Experiment (NSTX) currently uses a collection of analog signal processing solutions for coil protection. Part of the NSTX Upgrade (NSTX-U) entails replacing these analog systems with a software solution running on a conventional computing platform. The new Digital Coil Protection System (DCPS) will replace the old systems entirely, while also providing an extensible framework that allows adding new functionality as desired.

  13. Torsional suspension system for testing space structures

    NASA Technical Reports Server (NTRS)

    Reed, Wilmer H., III (Inventor); Gold, Ronald R. (Inventor)

    1991-01-01

    A low frequency torsional suspension system for testing a space structure uses a plurality of suspension stations attached to the space structure along the length thereof in order to suspend the space structure from an overhead support. Each suspension station includes a disk pivotally mounted to the overhead support, and two cables which have upper ends connected to the disk and lower ends connected to the space structure. The two cables define a parallelogram with the center of gravity of the space structure being vertically beneath the pivot axis of the disk. The vertical distance between the points of attachment of the cables to the disk and the pivot axis of the disk is adjusted to lower the frequency of the suspension system to a level which does not interfere with frequency levels of the space structure, thereby enabling accurate measurement.

  14. Pickup coil optimization for polarized 3He system

    NASA Astrophysics Data System (ADS)

    Tu, X. Q.; Zheng, H.; Sun, G. A.; Gong, J.; Ren, Y.; Liu, L. J.; Gao, P. L.; Wang, W. Z.; Yan, H.

    2017-07-01

    Not only can polarized 3He gas work as neutron spin filters (NSF) but also search for spin-dependent new interactions beyond the standard model. For both cases, the relative polarization of the spin polarized noble gas needs to be measured precisely. Various NMR techniques are applied practically to monitor the 3He cell's polarization. In this work, we tried to optimize the pickup coil for the spin exchange optical pump (SEOP) based 3He system. By optimizing the signal-to-noise ratio (SNR), we found that the coil should be wound by thin wire for a higher number of turns. The optimized sizes of the pickup coils depend on the detailed configurations. For a spherical 3He cell with radius a, we found the optimized coil radius is √{5}(a+d), where d is the coil to cell surface distance. For a cylindrical 3He cell with height h, for the configurations where the coils were placed either along or perpendicular to the longitudinal axis of the target cell, we derived the optimized sizes for the specific configurations. We believe these results are practically useful for designing pickup coils of polarized 3He systems.

  15. Investigation of cryosorption vacuum system and operation process for COIL

    NASA Astrophysics Data System (ADS)

    Xia, Liang-zhi; Wang, Jin-qu; Sang, Feng-ting; Zhao, Su-qin; Jin, Yu-qi; Fang, Ben-jie

    2007-05-01

    Cryosorption vacuum system for COIL is researched and developed. Adsorption chiller has been proposed and developed by improving the heat exchanger chiller. Compared with the heat exchanger chiller, the volume and LN II consumption of the new chiller were favourably reduced. In the present work, the new adsorption operation process, cryogenic pressure swing adsorption is adopted. Compared with thermal swing adsorption, regeneration time is shortened and LN II consumption is saved at least 80% in the new operation process. The cryosorption vacuum system was integrated to COIL and tested successfully. The weight of sorbent in adsorption bed is 22Kg, the total gas flowrate is about 0.5mol/s, the COIL's power maintains over 2kW, the total COIL's working time accounts to 100 seconds. It is concluded that the cryosorption vacuum system has the same pressure recovery capability as the large vacuum tank.

  16. Techniques For Microfabricating Coils For Microelectromechanical Systems Applications

    NASA Astrophysics Data System (ADS)

    Woods, R. C.; Powell, A. L.

    2008-01-01

    The advanced technology necessary for building future space exploration vehicles includes microfabricated coils for making possible self-inductances integrated with other passive and active electronic components. Integrated inductances make possible significant improvements in reliability over the traditional arrangement of using external discrete inductances, as well as allowing significant size (volume) reductions (also important in space vehicles). Two possible fabrication techniques (one using proprietary branded "Foturan" glass, the other using silicon wafer substrates) for microscopic coils are proposed, using electroplating into channels. The techniques have been evaluated for fabricating the planar electrical coils needed for typical microelectromechanical systems applications. There remain problems associated with processing using "Foturan" glass, but coil fabrication on silicon wafers was successful. Fabrication methods such as these are expected to play an important part in the development of systems and subsystems for forthcoming space exploration missions.

  17. Techniques For Microfabricating Coils For Microelectromechanical Systems Applications

    SciTech Connect

    Woods, R. C.; Powell, A. L.

    2008-01-21

    The advanced technology necessary for building future space exploration vehicles includes microfabricated coils for making possible self-inductances integrated with other passive and active electronic components. Integrated inductances make possible significant improvements in reliability over the traditional arrangement of using external discrete inductances, as well as allowing significant size (volume) reductions (also important in space vehicles). Two possible fabrication techniques (one using proprietary branded 'Foturan' glass, the other using silicon wafer substrates) for microscopic coils are proposed, using electroplating into channels. The techniques have been evaluated for fabricating the planar electrical coils needed for typical microelectromechanical systems applications. There remain problems associated with processing using 'Foturan' glass, but coil fabrication on silicon wafers was successful. Fabrication methods such as these are expected to play an important part in the development of systems and subsystems for forthcoming space exploration missions.

  18. Very low frequency suspension systems for dynamic testing. [of flexible spacecraft structures

    NASA Technical Reports Server (NTRS)

    Kienholz, David A.; Crawley, Edward F.; Harvey, T. Jeffrey

    1989-01-01

    Specifications for a Space Station suspension system which can provide rigid-body translation frequencies on the order of 0.1-0.2 Hz for a 50-foot payload weighing about 3400 lb and having a number of highly flexible appendages are discussed. Two suspension devices are considered, an all-mechanical passive device based on coil springs and a device using a combination of a passive pneumatic system and an active electromagnetic system. Test results show that both devices meet the initial requirements.

  19. Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching

    DOEpatents

    He, Jianliang; Rote, Donald M.

    1996-01-01

    A stabilization and propulsion system comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the super conducting magnets on the vehicle.

  20. Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching

    DOEpatents

    He, J.; Rote, D.M.

    1996-05-21

    A stabilization and propulsion system are disclosed comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the superconducting magnets on the vehicle. 12 figs.

  1. Air-Bearing-Piston Suspension System

    NASA Technical Reports Server (NTRS)

    Mullen, Donald; Bishop, Stephen J.

    1992-01-01

    Suspension system based on air-bearing piston holds up steel ball against gravitation while allowing ball to translate vertically and rotate freely. System designed to simulate effect of microgravity on ball. Applicable to suppression of vibrations and delicate machining processes.

  2. Open-loop characteristics of magnetic suspension systems using electromagnets mounted in a planar array

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.; Britcher, Colin P.

    1992-01-01

    The open-loop characteristics of a Large-Gap Magnetic Suspension System (LGMSS) were studied and numerical results are presented. The LGMSS considered provides five-degree-of-freedom control. The suspended element is a cylinder that contains a core composed of permanent magnet material. The magnetic actuators are air core electromagnets mounted in a planar array. Configurations utilizing five, six, seven, and eight electromagnets were investigated and all configurations were found to be controllable from coil currents and observable from suspended element positions. Results indicate that increasing the number of coils has an insignificant effect on mode shapes and frequencies.

  3. Design Optimization for a Maglev System Employing Flux Eliminating Coils

    NASA Technical Reports Server (NTRS)

    Davey, Kent R.

    1996-01-01

    Flux eliminating coils have received no little attention over the past thirty years as an alternative for realizing lift in a MAGLEV system. When the magnets on board the vehicle are displaced from the equilibrium or null flux point of these coils, they induce current in those coils which act to restore the coil to its null flux or centerline position. The question being addressed in this paper is that of how to choose the best coil for a given system. What appears at first glance to be an innocent question is in fact one that is actually quite involved, encompassing both the global economics and physics of the system. The real key in analyzing that question is to derive an optimization index or functional which represents the cost of the system subject to constraints, the primary constraint being that the vehicle lift itself at a certain threshold speed. Outlined in this paper is one scenario for realizing a total system design which uses sequential quadratic programming techniques.

  4. Electromagnetic free suspension system for space manufacturing. Volume 1: Technology department

    NASA Technical Reports Server (NTRS)

    Buerger, E. H.; Frost, R. T.; Lambert, R. H.; Oconnor, M. F.; Odell, E. L. G.; Napaluch, L. J.; Stockhoff, E. H.; Wouch, G.

    1972-01-01

    The technology developed in defining a facility to be used on the Skylab mission for electromagnetic suspension of small, molten spheres in the weightless space environment is described. The technologies discussed include: four-coil optimization, four-coil versus six-coil configuration comparison, four-coil position servocontrol, four-coil breadboard, position sensing and servosystem, two-color pyrometer, and specimen toration mode analysis.

  5. NSTX Protection And Interlock Systems For Coil And Powers Supply Systems

    SciTech Connect

    X. Zhao, S. Ramakrishnan, J. Lawson, C.Neumeyer, R. Marsala, H. Schneider, Engineering Operations

    2009-09-24

    NSTX at Princeton Plasma Physics Laboratory (PPPL) requires sophisticated plasma positioning control system for stable plasma operation. TF magnetic coils and PF magnetic coils provide electromagnetic fields to position and shape the plasma vertically and horizontally respectively. NSTX utilizes twenty six coil power supplies to establish and initiate electromagnetic fields through the coil system for plasma control. A power protection and interlock system is utilized to detect power system faults and protect the TF coils and PF coils against excessive electromechanical forces, overheating, and over current. Upon detecting any fault condition the power system is restricted, and it is either prevented from initializing or suppressed to de-energize coil power during pulsing. Power fault status is immediately reported to the computer system. This paper describes the design and operation of NSTX's protection and interlocking system and possible future expansion.

  6. Performance of Upgraded Cooling System for Lhd Helical Coils

    NASA Astrophysics Data System (ADS)

    Hamaguchi, S.; Imagawa, S.; Obana, T.; Yanagi, N.; Moriuchi, S.; Sekiguchi, H.; Oba, K.; Mito, T.; Motojima, O.; Okamura, T.; Semba, T.; Yoshinaga, S.; Wakisaka, H.

    2008-03-01

    Helical coils of the Large Helical Device (LHD) are large scale superconducting magnets for heliotron plasma experiments. The helical coils had been cooled by saturated helium at 4.4 K, 120 kPa until 2005. An upgrade of the cooling system was carried out in 2006 in order to improve the cryogenic stability of the helical coils and then it has been possible to supply the coils with subcooled helium at 3.2 K, 120 kPa. A designed mass flow of the supplied subcooled helium is 50 g/s. The subcooled helium is generated at a heat exchanger in a saturated helium bath. A series of two centrifugal cold compressors with gas foil bearing is utilized to lower the helium pressure in the bath. The supplied helium temperature is regulated by rotational speed of the cold compressors and power of a heater in the bath. The mass flow of the supplied helium is also controlled manually by a supply valve and its surplus is evaporated by ten heaters at the outlet above the coils. In the present study, the performance of the cooling system has been investigated and a stable operating method has also developed. As the result, it was confirmed that the performance of the upgraded cooling system satisfies the requirements.

  7. Analysis and experimental study of wireless power transfer with HTS coil and copper coil as the intermediate resonators system

    NASA Astrophysics Data System (ADS)

    Wang, Xiufang; Nie, Xinyi; Liang, Yilang; Lu, Falong; Yan, Zhongming; Wang, Yu

    2017-01-01

    Intermediate resonator (repeater) between transmitter and receiver can significantly increase the distance of wireless power transfer (WPT) and the efficiency of wireless power transfer. The wireless power transfer via strongly coupled magnetic resonances with an high temperature superconducting (HTS) coil and copper coil as intermediate resonators was presented in this paper. The electromagnetic experiment system under different conditions with different repeating coils were simulated by finite element software. The spatial distribution patterns of magnetic induction intensity at different distances were plotted. In this paper, we examined transfer characteristics with HTS repeating coil and copper repeating coil at 77 K and 300 K, respectively. Simulation and experimental results show that HTS and copper repeating coil can effectively enhance the space magnetic induction intensity, which has significant effect on improving the transmission efficiency and lengthening transmission distance. We found that the efficiency and the distance of wireless power transfer system with an HTS coil as repeater is much higher by using of copper coil as repeater.

  8. On the design of efficient multi-coil telemetry system for biomedical implants.

    PubMed

    Ramrakhyani, A K; Lazzi, G

    2013-02-01

    Two-coil based inductive coupling is a commonly used technique for wireless power and data transfer for biomedical implants. Because the source and load resistances are finite, two-coil systems generally achieve a relatively low power transfer efficiency. A novel multi-coil technique (using more than two coils) for wireless power and data transfer is considered to help overcoming this limitation. The proposed multi-coil system is formulated using both network theory and a two-port model. Using three or four coils for the wireless link allows for the source and load resistances to be decoupled from the Q-factor of the coils, resulting in a higher Q -factor and a corresponding improved power transfer efficiency (PTE). Moreover, due to the strong coupling between the driver and the transmitter coil (and/or between the receiver and the load coil), the multi-coil system achieves higher tunable frequency bandwidth as compared to its same sized two-coil equivalent. Because of the wider range of reflected impedance in the multi-coil system case, it is easier to tune the output power to the load and achieve the maximum power transfer condition for given source voltage than in a configuration with two coils. Experimental results showing a three-coil system achieving twice the efficiency and higher gain-bandwidth product compared to its two-coil counterpart are presented. In addition, a figure of merit for telemetry systems is defined to quantify the overall telemetry system performance.

  9. Development of a coiled tubing cable installation system

    SciTech Connect

    Newman, K.R.; Haver, N.A.; Stone, L.R.

    1995-12-31

    A system has been developed which installs and de-installs an electric wireline cable in coiled tubing (CT) while the CT is still on the reel. This cable installation system reduces the cost of a cable installation significantly compared with previous installation methods. This paper discusses the need for such a system, the theory used to develop this system, the various concepts considered, the system that was developed and test installation cases.

  10. Finite element analysis of the TPX toroidal field coil system

    SciTech Connect

    Myatt, R.L.

    1994-07-01

    A structural analysis of the Tokamak Physics Experiment (TPX) toroidal field (TF) coil system is presented. The large-scale structural behavior of the superconducting 16-coil magnet is simulated with a 3-D, cyclically-symmetric, two-coil, ANSYS model. The computer model is used to determine the displacement and stress state of the smeared winding pack and support structure, and to perform various structural evaluations. Approximating the detailed stress in the winding pack constituents based on smeared stress results and analytically derived component stress multipliers is discussed. The effectiveness of friction between wedged TF cases to help restrain out-of-plane electromagnetic forces is also considered. A stress evaluation of the conductor, insulation and structure is presented based on the TPX structural design criteria.

  11. Finite element analysis of the TPX toroidal field coil system

    NASA Astrophysics Data System (ADS)

    Myatt, R. Leonard

    1994-07-01

    A structural analysis of the Tokamak Physics Experiment (TPX) toroidal field (TF) coil system is presented. The large-scale structural behavior of the superconducting 16-coil magnet is simulated with a 3-D, cyclically-symmetric, two-coil, ANSYS (1) model. The computer model is used to determine the displacement and stress state of the smeared winding pack and support structure, and to perform various structural evaluations. Approximating the detailed stresses in the winding pack constituents based on smeared stress results and analytically derived component stress multipliers is discussed. The effectiveness of friction between wedged TF cases to help restrain out-of-plane electromagnetic forces is also considered. A stress evaluation of the conductor, insulation and structure is presented based on the TPX structural design criteria.

  12. Dual inductive link coil design for a neural recording system.

    PubMed

    Rush, Alexander; Troyk, Philip R

    2011-01-01

    This paper reports an approach to the physical design of the coils used in a dual inductive link to provide two-way wireless communication and power for a neural recording system. The design approach makes use of an analytic model of the link performance in terms of the physical parameters of the link, which allows physical parameters to be iterated on a computer rather than on the bench to find the optimal design within the physical restrictions imposed. In particular, this approach was used to choose the optimal implant data coil sizing to maximize the difference between the contributions of the constructive and destructive paths of the reverse telemetry signal.

  13. Structural analysis of compression helical spring used in suspension system

    NASA Astrophysics Data System (ADS)

    Jain, Akshat; Misra, Sheelam; Jindal, Arun; Lakhian, Prateek

    2017-07-01

    The main aim of this work has to develop a helical spring for shock absorber used in suspension system which is designed to reduce shock impulse and liberate kinetic energy. In a vehicle, it increases comfort by decreasing amplitude of disturbances and it improves ride quality by absorbing and dissipating energy. When a vehicle is in motion on a road and strikes a bump, spring comes into action quickly. After compression, spring will attempt to come to its equilibrium state which is on level road. Helical springs can be made lighter with more strength by reducing number of coils and increasing the area. In this research work, a helical spring is modeled and analyzed to substitute the existing steel spring which is used in suspension. By using different materials, stress and deflection of helical spring can be varied. Comparability between existing spring and newly replaced spring is used to verify the results. For finding detailed stress distribution, finite element analysis is used to find stresses and deflection in both the helical springs. Finite element analysis is a method which is used to find proximate solutions of a physical problem defined in a finite domain. In this research work, modeling of spring is accomplished using Solid Works and analysis on Ansys.

  14. The Annular Suspension and Pointing System /ASPS/

    NASA Technical Reports Server (NTRS)

    Anderson, W. W.; Woolley, C. T.

    1978-01-01

    The Annular Suspension and Pointing System (ASPS) may be attached to a carrier vehicle for orientation, mechanical isolation, and fine pointing purposes applicable to space experiments. It has subassemblies for both coarse and vernier pointing. A fourteen-degree-of-freedom simulation of the ASPS mounted on a Space Shuttle has yielded initial performance data. The simulation describes: the magnetic actuators, payload sensors, coarse gimbal assemblies, control algorithms, rigid body dynamic models of the payload and Shuttle, and a control system firing model.

  15. Equilibrium modeling of the TFCX poloidal field coil system

    SciTech Connect

    Strickler, D.J.; Miller, J.B.; Rothe, K.E.; Peng, Y.K.M.

    1984-04-01

    The Toroidal Fusion Core Experiment (TFCX) isproposed to be an ignition device with a low safety factor (q approx. = 2.0), rf or rf-assisted startup, long inductive burn pulse (approx. 300 s), and an elongated plasma cross section (kappa = 1.6) with moderate triangularity (delta = 0.3). System trade studies have been carried out to assist in choosing an appropriate candidate for TFCX conceptual design. This report describes an important element in these system studies - the magnetohydrodynamic (MHD) equilibrium modeling of the TFCX poloidal field (PF) coil system and its impact on the choice of machine size. Reference design points for the all-super-conducting toroidal field (TF) coil (TFCX-S) and hybrid (TFCX-H) options are presented that satisfy given PF system criteria, including volt-second requirements during burn, mechanical configuration constraints, maximum field constraints at the superconducting PF coils, and plasma shape parameters. Poloidal coil current waveforms for the TFCX-S and TFCX-H reference designs consistent with the equilibrium requirements of the plasma startup, heating, and burn phases of a typical discharge scenario are calculated. Finally, a possible option for quasi-steady-state operation is discussed.

  16. GSA-Tuning IPD Control of a Field-Sensed Magnetic Suspension System.

    PubMed

    Li, Jen-Hsing; Chiou, Juing-Shian

    2015-12-16

    The purpose of this paper is to propose a GSA-tuning IPD control technique for magnetic suspension systems. An educational demonstration on a magnetic-field sensed magnetic suspension system is examined for effectiveness. For the magnetic-field sensed magnetic suspension system (FSMSS), the current transducer is employed for measuring the electromagnetic coil current, and a Hall effect device is used for detecting the position of the suspended object. To achieve optimal performance, the gravitational search algorithm (GSA) is adopted for tuning the integral-proportional-derivative (IPD) controller. The IPD control includes the specified PD controller and an integrator. The specified PD control is employed for stabilizing the inherently unstable FSMSS, whereas the integral control is utilized for eliminating the steady-state error. The GSA can tune the IPD control parameters to enable optimal FSMSS performance. We achieved excellent results from the simulations and hands-on experiments for the proposed control strategies and structures.

  17. GSA-Tuning IPD Control of a Field-Sensed Magnetic Suspension System

    PubMed Central

    Li, Jen-Hsing; Chiou, Juing-Shian

    2015-01-01

    The purpose of this paper is to propose a GSA-tuning IPD control technique for magnetic suspension systems. An educational demonstration on a magnetic-field sensed magnetic suspension system is examined for effectiveness. For the magnetic-field sensed magnetic suspension system (FSMSS), the current transducer is employed for measuring the electromagnetic coil current, and a Hall effect device is used for detecting the position of the suspended object. To achieve optimal performance, the gravitational search algorithm (GSA) is adopted for tuning the integral-proportional-derivative (IPD) controller. The IPD control includes the specified PD controller and an integrator. The specified PD control is employed for stabilizing the inherently unstable FSMSS, whereas the integral control is utilized for eliminating the steady-state error. The GSA can tune the IPD control parameters to enable optimal FSMSS performance. We achieved excellent results from the simulations and hands-on experiments for the proposed control strategies and structures. PMID:26694404

  18. 15 CFR 2011.207 - Suspension of the certificate system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... OFFICE OF THE UNITED STATES TRADE REPRESENTATIVE ALLOCATION OF TARIFF-RATE QUOTA ON IMPORTED SUGARS, SYRUPS AND MOLASSES Specialty Sugar § 2011.207 Suspension of the certificate system. (a) Suspension....

  19. 15 CFR 2011.207 - Suspension of the certificate system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... OFFICE OF THE UNITED STATES TRADE REPRESENTATIVE ALLOCATION OF TARIFF-RATE QUOTA ON IMPORTED SUGARS, SYRUPS AND MOLASSES Specialty Sugar § 2011.207 Suspension of the certificate system. (a) Suspension. The...

  20. 15 CFR 2011.207 - Suspension of the certificate system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... OFFICE OF THE UNITED STATES TRADE REPRESENTATIVE ALLOCATION OF TARIFF-RATE QUOTA ON IMPORTED SUGARS, SYRUPS AND MOLASSES Specialty Sugar § 2011.207 Suspension of the certificate system. (a) Suspension. The...

  1. 15 CFR 2011.207 - Suspension of the certificate system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Suspension of the certificate system. 2011.207 Section 2011.207 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements..., SYRUPS AND MOLASSES Specialty Sugar § 2011.207 Suspension of the certificate system. (a) Suspension. The...

  2. 15 CFR 2011.207 - Suspension of the certificate system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Suspension of the certificate system. 2011.207 Section 2011.207 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements..., SYRUPS AND MOLASSES Specialty Sugar § 2011.207 Suspension of the certificate system. (a) Suspension. The...

  3. Database system for analysing and managing coiled tubing drilling data

    NASA Astrophysics Data System (ADS)

    Suh, J.; Choi, Y.; Park, H.; Choe, J.

    2009-05-01

    This study present a prototype of database system for analysing and managing petrophysical data from coiled tubing drilling in the oil and gas industry. The characteristics of coiled tubing drilling data from cores were analyzed and categorized according to the whole drilling process and data modeling including object relation diagram, class diagram was carried out to design the schema of effective database system such as the relationships between tables and key index fields to create the relationships. The database system called DrillerGeoDB consists of 22 tables and those are classified with 4 groups such as project information, stratum information, drilling/logging information and operation evaluate information. DrillerGeoDB provide all sort of results of each process with a spreadsheet such as MS-Excel via application of various algorithm of logging theory and statistics function of cost evaluation. This presentation describes the details of the system development and implementation.

  4. An Introduction to the Virgo Suspension System

    NASA Astrophysics Data System (ADS)

    Frasconi, Franco; Rapagnani, Piero

    Suspending the mirrors is one of the most crucial tasks in gravitational wave interferometer technology. The performance of the suspensions must provide the required attenuation of seismic noise and reduction of thermal noise, two fundamental limits to the sensitivity of any gravitational wave detector. Moreover, the suspension system must be equipped with sensors and actuators which are used to actively control some relevant degrees of freedom, so to be able to keep the interferometer at its working point (i.e., "locked"). In the first part of this chapter, we deal with the basic principles behind the Superattenuator chains developed in Virgo to reduce the seismic noise. In the second part, we illustrate the techniques to reduce the thermal noise in the detection bandwidth, according to the theory illustrated in Chap. 8, 10.1007/978-3-319-03792-9_8.

  5. Prospective randomized trial comparing pushable coil and detachable coil during percutaneous implantation of port-catheter system for hepatic artery infusion chemotherapy.

    PubMed

    Park, Sung Ii; Lee, Shin Jae; Lee, Myungsu; Lee, Mu Sook; Kim, Gyoung Min; Kim, Man Deuk; Won, Jong Yun; Lee, Do Yun

    2015-03-01

    The purpose of this study was to prospectively compare the efficacy and controllability of pushable coil and detachable coil during embolization of gastroduodenal artery (GDA) while performing percutaneous implantation of port-catheter system for hepatic artery infusion chemotherapy. Fifty patients (M:F = 42:8, age: 31-81 years) with advanced hepatocellular carcinoma undergoing port-catheter system implantation were randomized into pushable coil group and detachable coil group. During catheter fixation, GDA was embolized as close to the origin as possible. Success rate, number of coils used, number of coils removed due to malposition after deployment, time to occlusion, uncoiled GDA length, pushability, and complications were compared. Pushability was graded as no tension, slight tension, and difficult to advance. Embolization was successful in 49 patients. One failure resulted from repeated regurgitation of pushable coil into hepatic artery. Number of coils used and removed coils, time to occlusion, and uncoiled GDA length were 1-3 (mean 2.32), 5 coils in 3 patients, 4-20 min (mean 8.00), and 0-15.0 mm (mean 3.36) in pushable coil group, and 1-5 (mean 2.12), 2 coils in 2 patients, 2-15 min (mean 7.40), and 0-10.2 mm (mean 2.92) in detachable coil group, respectively, without significant difference. Pushability was no tension (n = 24) and slight tension (n = 1) in pushable coil group and no tension (n = 16), slight tension (n = 7), and difficult to advance (n = 2) in detachable coil group. One hepatic artery dissection occurred in the failed case during coil removal. Pushable coils and detachable coils had similar efficacy and controllability during GDA embolization, although there was a trend favoring detachable coil.

  6. The fast correction coil feedback control system

    SciTech Connect

    Coffield, F.; Caporaso, G.; Zentler, J.M.

    1989-01-01

    A model-based feedback control system has been developed to correct beam displacement errors in the Advanced Test Accelerator (ATA) electron beam accelerator. The feedback control system drives an X/Y dipole steering system that has a 40-MHz bandwidth and can produce {+-}300-Gauss-cm dipole fields. A simulator was used to develop the control algorithm and to quantify the expected performance in the presence of beam position measurement noise and accelerator timing jitter. The major problem to date has been protecting the amplifiers from the voltage that is inductively coupled to the steering bars by the beam. 3 refs., 8 figs.

  7. Functional specifications of the annular suspension pointing system, appendix A

    NASA Technical Reports Server (NTRS)

    Edwards, B.

    1980-01-01

    The Annular Suspension Pointing System is described. The Design Realization, Evaluation and Modelling (DREAM) system, and its design description technique, the DREAM Design Notation (DDN) is employed.

  8. Feasibility Study: Ductless Hydronic Distribution Systems with Fan Coil Delivery

    SciTech Connect

    Springer, D.; Dakin, B.; Backman, C.

    2012-07-01

    The primary objectives of this study are to estimate potential energy savings relative to conventional ducted air distribution, and to identify equipment requirements, costs, and barriers with a focus on ductless hydronic delivery systems that utilize water-to-air terminal units in each zone. Results indicate that annual heating and cooling energy use can be reduced by up to 27% assuming replacement of the conventional 13 SEER heat pump and coil with a similarly rated air-to-water heat pump.

  9. A novel system of coils for magnetobiology research

    NASA Astrophysics Data System (ADS)

    Makinistian, L.

    2016-11-01

    A novel system of coils for testing in vitro magnetobiological effects was designed, simulated, and built. Opposite to what is usual, the system generates a controlled gradient of magnetic field. This feature is introduced to allow the assessment of multiple values of the field in a single experiment. The apparatus consists of two flattened orthogonal coils, which permit independent control of two of the spatial components of the field. Geometry of design, combined with the use of a standard multi-well microplate for cellular culture, allows for simultaneous testing of 96 different field conditions. The system, intended to increase the efficiency of evaluating biological effects throughout ranges of the field parameters, was fully characterized injecting DC currents to the coils (i.e., generating static magnetic fields) in order to assess the spatial distribution of both the field's and field-gradient's components. Temperature load was carefully evaluated and the maximum values of 350 μT and 9 μT/mm (for the field and its gradient) could be generated without excessive heating of the cellular cultures.

  10. Neural control of magnetic suspension systems

    NASA Technical Reports Server (NTRS)

    Gray, W. Steven

    1993-01-01

    The purpose of this research program is to design, build and test (in cooperation with NASA personnel from the NASA Langley Research Center) neural controllers for two different small air-gap magnetic suspension systems. The general objective of the program is to study neural network architectures for the purpose of control in an experimental setting and to demonstrate the feasibility of the concept. The specific objectives of the research program are: (1) to demonstrate through simulation and experimentation the feasibility of using neural controllers to stabilize a nonlinear magnetic suspension system; (2) to investigate through simulation and experimentation the performance of neural controllers designs under various types of parametric and nonparametric uncertainty; (3) to investigate through simulation and experimentation various types of neural architectures for real-time control with respect to performance and complexity; and (4) to benchmark in an experimental setting the performance of neural controllers against other types of existing linear and nonlinear compensator designs. To date, the first one-dimensional, small air-gap magnetic suspension system has been built, tested and delivered to the NASA Langley Research Center. The device is currently being stabilized with a digital linear phase-lead controller. The neural controller hardware is under construction. Two different neural network paradigms are under consideration, one based on hidden layer feedforward networks trained via back propagation and one based on using Gaussian radial basis functions trained by analytical methods related to stability conditions. Some advanced nonlinear control algorithms using feedback linearization and sliding mode control are in simulation studies.

  11. Inductance and resistance measurement method for vessel detection and coil powering in all-surface inductive heating systems composed of outer squircle coils

    NASA Astrophysics Data System (ADS)

    Kilic, Veli Tayfun; Unal, Emre; Demir, Hilmi Volkan

    2017-05-01

    In this work, we investigate a method proposed for vessel detection and coil powering in an all-surface inductive heating system composed of outer squircle coils. Besides conventional circular coils, coils with different shapes such as outer squircle coils are used for and enable efficient all-surface inductive heating. Validity of the method, which relies on measuring inductance and resistance values of a loaded coil at different frequencies, is experimentally demonstrated for a coil with shape different from conventional circular coil. Simple setup was constructed with a small coil to model an all-surface inductive heating system. Inductance and resistance maps were generated by measuring coil's inductance and resistance values at different frequencies loaded by a plate made of different materials and located at various positions. Results show that in an induction hob for various coil geometries it is possible to detect a vessel's presence, to identify its material type and to specify its position on the hob surface by considering inductance and resistance of the coil measured on at least two different frequencies. The studied method is important in terms of enabling safe, efficient and user flexible heating in an all-surface inductive heating system by automatically detecting the vessel's presence and powering on only the coils that are loaded by the vessel with predetermined current levels.

  12. Recent aerodynamic measurements with Magnetic Suspension Systems

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.

    1989-01-01

    This paper reviews recent aerodynamic tests of a family of slanted-base ogive-cylinders using the NASA Langley 13-inch Magnetic Suspension and Balance System. Results include drag, lift, pitching moment, support interference and base pressure measurements. Mach numbers were in the range 0.04 to 0.2. Drag results are shown to be in satisfactory agreement with previous measurements. Significant support interferences were found at all test conditions. Comparison is made between interference free base pressures, obtained using remote telemetry, and sting cavity pressures. Test results and procedures are briefly discussed in the context of the proposed helium flow facility.

  13. Quantitative and qualitative comparison of a new prosthetic suspension system with two existing suspension systems for lower limb amputees.

    PubMed

    Eshraghi, Arezoo; Abu Osman, Noor Azuan; Karimi, Mohammad Taghi; Gholizadeh, Hossien; Ali, Sadeeq; Wan Abas, Wan Abu Bakar

    2012-12-01

    The objectives of this study were to compare the effects of a newly designed magnetic suspension system with that of two existing suspension methods on pistoning inside the prosthetic socket and to compare satisfaction and perceived problems among transtibial amputees. In this prospective study, three lower limb prostheses with three different suspension systems were fabricated for ten transtibial amputees. The participants used each of the three prostheses for 1 mo in random order. Pistoning inside the prosthetic socket was measured by motion analysis system. The Prosthesis Evaluation Questionnaire was used to evaluate satisfaction and perceived problems with each suspension system. The lowest pistoning motion was found with the suction system compared with the other two suspension systems (P < 0.05). The new suspension system showed peak pistoning values similar to that of the pin lock system (P = 0.086). The results of the questionnaire survey revealed significantly higher satisfaction rates with the new system than with the other two systems in donning and doffing, walking, uneven walking, stair negotiation, and overall satisfaction (P < 0.05). The new suspension system has the potential to be used as an alternative to the available suspension systems. The pistoning motion was comparable to that of the other two systems. The new system showed compatible prosthetic suspension with the other two systems (suction and pin lock). The satisfaction with donning and doffing was high with the magnetic system. Moreover, the subjects reported fewer problems with the new system.

  14. System and technique for ultrasonic characterization of settling suspensions

    DOEpatents

    Greenwood, Margaret S.; Panetta, Paul D.; Bamberger, Judith A.; Pappas, Richard A.

    2006-11-28

    A system for determining properties of settling suspensions includes a settling container, a mixer, and devices for ultrasonic interrogation transverse to the settling direction. A computer system controls operation of the mixer and the interrogation devices and records the response to the interrogating as a function of settling time, which is then used to determine suspension properties. Attenuation versus settling time for dilute suspensions, such as dilute wood pulp suspension, exhibits a peak at different settling times for suspensions having different properties, and the location of this peak is used as one mechanism for characterizing suspensions. Alternatively or in addition, a plurality of ultrasound receivers are arranged at different angles to a common transmitter to receive scattering responses at a variety of angles during particle settling. Angular differences in scattering as a function of settling time are also used to characterize the suspension.

  15. Periprocedural safety of aneurysm embolization with the Medina Coil System: the early human experience.

    PubMed

    Turk, Aquilla S; Maia, Orlando; Ferreira, Christian Candido; Freitas, Diogo; Mocco, J; Hanel, Ricardo

    2016-02-01

    Intracranial saccular aneurysms, if untreated, carry a high risk of morbidity and mortality from intracranial bleeding. Embolization coils are the most common treatment. We describe the periprocedural safety and performance of the initial human experience with the next generation Medina Coil System. The Medina Coil System is a layered three-dimensional coil made from a radiopaque, shape set core wire, and shape memory alloy outer coil filaments. Nine aneurysms in five patients were selected for treatment with the Medina Coil System. Nine aneurysms in five patients, ranging from 5 to 17 mm in size in various locations, were treated with the Medina Coil System. No procedural or periprocedural complications were encountered. Procedure times, number of coils used to treat the aneurysm, and use of adjunctive devices were much less than anticipated if conventional coil technology had been used. The Medina Coil System is a next generation coil that combines all of the familiar and expected procedural safety and technique concepts associated with conventional coils. We found improved circumferential aneurysm filling, which may lead to improved long term outcomes, with fewer devices and faster operating times. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  16. Dual trailing arm vehicle suspension system

    SciTech Connect

    Weitzenhof, D.A.; Sayre, C.F.

    1986-11-18

    This patent describes a vehicle suspension system adapted to be interposed between a vehicle frame and at least two wheels arranged one in advance of the other on a side of the vehicle frame; the suspension system including: (a) at least two axles on a side of the vehicle frame for independently rotatably mounting each of the wheels; (b) at least two trailing arms, each of the arms being attached at one end to a respective axle and extending forwardly from the axle wherein the number of the trailing arms does not exceed the number of axles; (c) at least two pivot means mounted on the vehicle frame and connected to the other end of the trailing arms for pivotally mounting the vehicle frame wherein the number of the pivot means, does not exceed the number of axles; (d) lever means attached to and extending outwardly from each of the pivot means for pivotal movement with the pivot means means in relationship to movement of the trailing arms, with the length of the lever means being independent of the spacing between the axles; and (e) elastomer spring means extending between and pivotally mounted on the lever means for absorbing and balancing the forces exerted on the wheels particularly during braking and when encountering variations in the road surface.

  17. Suspension systems for ground testing large space structures

    NASA Technical Reports Server (NTRS)

    Gold, Ronald R.; Friedman, Inger P.; Reed, Wilmer H., III; Hallauer, W. L.

    1990-01-01

    A research program is documented for the development of improved suspension techniques for ground vibration testing of large, flexible space structures. The suspension system must support the weight of the structure and simultaneously allow simulation of the unconstrained rigid-body movement as in the space environment. Exploratory analytical and experimental studies were conducted for suspension systems designed to provide minimum vertical, horizontal, and rotational degrees of freedom. The effects of active feedback control added to the passive system were also investigated. An experimental suspension apparatus was designed, fabricated, and tested. This test apparatus included a zero spring rate mechanism (ZSRM) designed to support a range of weights from 50 to 300 lbs and provide vertical suspension mode frequencies less than 0.1 Hz. The lateral suspension consisted of a pendulum suspended from a moving cart (linear bearing) which served to increase the effective length of the pendulum. The torsion suspension concept involved dual pendulum cables attached from above to a pivoting support (bicycle wheel). A simple test structure having variable weight and stiffness characteristics was used to simulate the vibration characteristics of a large space structure. The suspension hardware for the individual degrees of freedom was analyzed and tested separately and then combined to achieve a 3 degree of freedom suspension system. Results from the exploratory studies should provide useful guidelines for the development of future suspension systems for ground vibration testing of large space structures.

  18. Rugged telemetry system for coiled-tubing earth drilling

    NASA Astrophysics Data System (ADS)

    Weis, R. Stephen; Beadle, Brad M.

    1997-09-01

    The development of a rugged optical fiber telemetry system for coiled-tubing earth-drilling is described. The transmitter and receiver of the telemetry system are located on the surface. A high temperature fiber cable connects a serial array of downhole modulators with the surface. Each modulator consists of an intrinsic fiber Bragg grating (FBG) fixed to a piezoelectric transducer (PZ). Each modulating signal causes a PZ to stretch its attached FBG, shifting the wavelength of the light reflected by the grating. The wavelength shift of the grating-reflected light is detected at the output using a Mach-Zehnder interferometer.

  19. Advanced Mud System for Microhole Coiled Tubing Drilling

    SciTech Connect

    Kenneth Oglesby

    2008-12-01

    An advanced mud system was designed and key components were built that augment a coiled tubing drilling (CTD) rig that is designed specifically to drill microholes (less than 4-inch diameter) with advanced drilling techniques. The mud system was tailored to the hydraulics of the hole geometries and rig characteristics required for microholes and is capable of mixing and circulating mud and removing solids while being self contained and having zero discharge capability. Key components of this system are two modified triplex mud pumps (High Pressure Slurry Pumps) for advanced Abrasive Slurry Jetting (ASJ) and a modified Gas-Liquid-Solid (GLS) Separator for well control, flow return and initial processing. The system developed also includes an additional component of an advanced version of ASJ which allows cutting through most all materials encountered in oil and gas wells including steel, cement, and all rock types. It includes new fluids and new ASJ nozzles. The jetting mechanism does not require rotation of the bottom hole assembly or drill string, which is essential for use with Coiled Tubing (CT). It also has low reactive forces acting on the CT and generates cuttings small enough to be easily cleaned from the well bore, which is important in horizontal drilling. These cutting and mud processing components and capabilities compliment the concepts put forth by DOE for microhole coiled tubing drilling (MHTCTD) and should help insure the reality of drilling small diameter holes quickly and inexpensively with a minimal environmental footprint and that is efficient, compact and portable. Other components (site liners, sump and transfer pumps, stacked shakers, filter membranes, etc.. ) of the overall mud system were identified as readily available in industry and will not be purchased until we are ready to drill a specific well.

  20. Evaluation of new suspension system for limb prosthetics

    PubMed Central

    2014-01-01

    Background Good prosthetic suspension system secures the residual limb inside the prosthetic socket and enables easy donning and doffing. This study aimed to introduce, evaluate and compare a newly designed prosthetic suspension system (HOLO) with the current suspension systems (suction, pin/lock and magnetic systems). Methods All the suspension systems were tested (tensile testing machine) in terms of the degree of the shear strength and the patient’s comfort. Nine transtibial amputees participated in this study. The patients were asked to use four different suspension systems. Afterwards, each participant completed a questionnaire for each system to evaluate their comfort. Furthermore, the systems were compared in terms of the cost. Results The maximum tensile load that the new system could bear was 490 N (SD, 5.5) before the system failed. Pin/lock, magnetic and suction suspension systems could tolerate loads of580 N (SD, 8.5), 350.9 (SD, 7) and 310 N (SD, 8.4), respectively. Our subjects were satisfied with the new hook and loop system, particularly in terms of easy donning and doffing. Furthermore, the new system is considerably cheaper (35 times) than the current locking systems in the market. Conclusions The new suspension system could successfully retain the prosthesis on the residual limb as a good alternative for lower limb amputees. In addition, the new system addresses some problems of the existing systems and is more cost effective than its counterparts. PMID:24410918

  1. A novel radio frequency coil for veterinary magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Meng, Bin; Huang, Kai-Wen; Wang, Wei-Min

    2010-07-01

    In this article, a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system. Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil. The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation. The size and the shape of the new coil are optimized and validated by simulation through using the finite element method (FEM). Good magnetic resonance (MR) images are achieved on a shepherd dog.

  2. Thermal and mechanical characteristics of loudspeakers using a magnetic gap filled with a magnetorheological suspension

    SciTech Connect

    Shul'man, Z.P.; Kordonskii, V.I.; Khusid, B.M.; Voronovich, G.K.; Demchuk, S.A.; Kuz'min, V.A.

    1988-07-01

    This paper presents some theoretical and experimental results of a study of the heat-transfer characteristics of the voice coil of an electrodynamic loudspeaker and the mechanics of its movable system for a gap filled with a magnetorheological suspension. The heat transfer and motion of the voice coil of a type 4GD-35 electrodynamic loudspeaker were investigated experimentally at the resonance frequency. The coil was heated by a high-frequency signal which was delivered together with the low-frequency signal driving the coil. The motion of the coil under unsteady nonisothermal conditions was modeled under the assumption that the suspension undergoes Couette flow in the gap of the coil.

  3. Efficient optimal design of suspension systems for rotating shafts

    NASA Technical Reports Server (NTRS)

    Pilkey, W. D.; Wang, B. P.; Vannoy, D.

    1975-01-01

    A new technique is proposed for the optimum design of suspension systems for rotating shafts. In this approach the conventional method of trial and error search for optimum parameter values for a prescribed design configuration has been replaced by an efficient two-stage procedure. In the first stage a generic force is substituted for the suspension system to be designed and the absolute optimum (or limiting) performance characteristics of the shaft are computed. In the second stage, using a chosen suspension system configuration, parameter identification techniques are are applied to find the design parameters so that the suspension system will respond as close as possible to the absolute optimal performance. In this approach the repetitive shaft analyses required in the conventional search techniques are avoided. Hence, the new technique is relatively efficient computationally and is suitable for large systems. Both linear and nonlinear suspension systems can be designed. A simple Jeffcott rotor is used to demonstrate the new technique.

  4. Superconducting coil system and methods of assembling the same

    DOEpatents

    Rajput-Ghoshal, Renuka; Rochford, James H.; Ghoshal, Probir K.

    2016-01-19

    A superconducting magnet apparatus is provided. The superconducting magnet apparatus includes a power source configured to generate a current; a first switch coupled in parallel to the power source; a second switch coupled in series to the power source; a coil coupled in parallel to the first switch and the second switch; and a passive quench protection device coupled to the coil and configured to by-pass the current around the coil and to decouple the coil from the power source when the coil experiences a quench.

  5. 15 CFR 2011.110 - Suspension of certificate system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Suspension of certificate system. 2011.110 Section 2011.110 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements..., SYRUPS AND MOLASSES Certificate of Quota Eligibility § 2011.110 Suspension of certificate system. (a...

  6. 15 CFR 2011.110 - Suspension of certificate system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Suspension of certificate system. 2011.110 Section 2011.110 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements..., SYRUPS AND MOLASSES Certificate of Quota Eligibility § 2011.110 Suspension of certificate system. (a...

  7. 15 CFR 2011.110 - Suspension of certificate system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Suspension of certificate system. 2011.110 Section 2011.110 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements..., SYRUPS AND MOLASSES Certificate of Quota Eligibility § 2011.110 Suspension of certificate system. (a...

  8. 15 CFR 2011.110 - Suspension of certificate system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Suspension of certificate system. 2011.110 Section 2011.110 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements..., SYRUPS AND MOLASSES Certificate of Quota Eligibility § 2011.110 Suspension of certificate system. (a...

  9. 15 CFR 2011.110 - Suspension of certificate system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Suspension of certificate system. 2011.110 Section 2011.110 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements..., SYRUPS AND MOLASSES Certificate of Quota Eligibility § 2011.110 Suspension of certificate system. (a...

  10. Suspension System Provides Independent Translation And Rotation

    NASA Technical Reports Server (NTRS)

    Heeg, Jennifer

    1994-01-01

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

  11. Magnetic suspension and balance system (MSBS) advanced study.I - System design

    NASA Technical Reports Server (NTRS)

    Boom, Roger W.; Abdelsalam, Mostafa K.; Eyssa, Yehia M.; Mcintosh, Glen E.

    1987-01-01

    A magnetic suspension and balance system is designed to support models of aircraft or other objects in wind tunnels by means of magnetic forces. Major design improvements have been achieved, resulting in reductions of the system size, weight, and cost. These improvements are due to: (1) the use of holmium in the model core to increase its magnetic moment, (2) the use of a powerful new permanent magnet material in the model wings, (3) a new arrangement for the roll coils, and (4) the use of a nonmetallic structure to eliminate eddy current losses. The conceptual design of the holmium core superconductive solenoid and of the new permanent magnet wing assembly is described in detail. The discussion includes comparisons of the pole strengths for different model core magnets, the design of a superconducting solenoid and cryostat, and the analysis of model wing magnetic requirements.

  12. Magnetic field uniformity of the practical tri-axial Helmholtz coils systems.

    PubMed

    Beiranvand, R

    2014-05-01

    In this paper, effects of the assembly misalignments and the manufacturing mismatches on the magnetic field uniformity of a practical tri-axial Helmholtz coils system have been modeled mathematically. These undesired effects regularly occur in any practical tri-axial Helmholtz coils system. To confirm the mathematical calculations, a tri-axial Helmholtz coils system has been constructed and the uniformity of its magnetic field has been measured under different conditions. The experimental results are in good agreement with the mathematical analyses.

  13. Oval gradient coils for an open magnetic resonance imaging system with a vertical magnetic field

    NASA Astrophysics Data System (ADS)

    Matsuzawa, Koki; Abe, Mitsushi; Kose, Katsumi; Terada, Yasuhiko

    2017-05-01

    Existing open magnetic resonance imaging (MRI) systems use biplanar gradient coils for the spatial encoding of signals. We propose using novel oval gradient coils for an open vertical-field MRI. We designed oval gradients for a 0.3 T open MRI system and showed that such a system could outperform a traditional biplanar gradient system while maintaining adequate gradient homogeneity and subject accessibility. Such oval gradient coils would exhibit high efficiency, low inductance and resistance, and high switching capability. Although the designed oval Y and Z coils showed more heat dissipation and less cooling capability than biplanar coils with the same gap, they showed an efficient heat-dissipation path to the surrounding air, which would alleviate the heat problem. The performance of the designed oval-coil system was demonstrated experimentally by imaging a human hand.

  14. Integrated Design System of Toroidal Field Coil for CFETR

    NASA Astrophysics Data System (ADS)

    Luo, Zhiren; Liu, Xufeng; Du, Shuangsong; Wang, Zhongwei; Song, Yuntao

    2016-09-01

    Integrating engineering software is meaningful but challenging for a system code of a fusion device. This issue is seldom considered by system codes currently. Therefore, to discuss the issue, the Integrated Design System of TF Coil (IDS-TFC) has been worked out, which consists of physical calculation, CAD, and Finite Element Analysis (FEA). Furthermore, an Integrated and Automatically Optimized Method (IAOM) has been created to address the integration and interfaces. The method utilizes a geometry parameter to connect each design submodule and achieve automatic optimization. Double-objectives optimization has been realized, confirming it is feasible to integrate and optimize engineering design and physical calculation. Moreover, IDS-TFC can also serve as a useful reference of integrated design processing for subsequent fusion design. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2014GB110000, 2014GB110002)

  15. Application of a run around coil system to a roof fan house at Michoud Assembly Facility at New Orleans, Louisiana

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Analysis of the proposed run around coil system indicates that it offers a decrease in steam, electricity and water consumptions. The run around coil system consist of two coils, a precooling coil which will be located at up stream and a reheating coil which will be located at down stream of the chilled water spray chamber. This system will provide the necessary reheat in summer, spring and fall. At times, if the run around coil system can not provide the necessary reheat, the existing reheat coil could be utilized.

  16. Suspension system for gimbal supported scanning payloads

    NASA Technical Reports Server (NTRS)

    Polites, Michael E. (Inventor)

    1995-01-01

    Gimballed scanning devices or instruments are the subject of this invention. Scanning is an important aspect of space science. To achieve a scan pattern some means must be provided which impart to the payload an oscillatory motion. Various forms of machines have been employed for controllably conferring on scanning instruments predetermined scan patterns. They include control moment gyroscopes, reaction wheels, torque motors, reaction control systems, and the like. But rotating unbalanced mass (RUM) devices are a new and efficient way to generate scans in gimballed payloads. RUM devices are superior to previous scanning apparatus, but they require power consuming and frequently complex auxiliary control systems to position and reposition the particular scan pattern relative to a target or a number of targets. Herein the control system is simplified. The most frequently employed method for achieving the various scan patterns is to gimbal the scanning device. Gimbals are suspended in such a way that they can be activated to generate the scan pattern. The suspension means described is for payloads supported in gimbals wherein the payload rotation is restricted by a flex pivot so that the payload oscillates, thereby moving in a scan pattern.

  17. Suspension system for gimbal supported scanning payloads

    NASA Astrophysics Data System (ADS)

    Polites, Michael E.

    1995-03-01

    Gimballed scanning devices or instruments are the subject of this invention. Scanning is an important aspect of space science. To achieve a scan pattern some means must be provided which impart to the payload an oscillatory motion. Various forms of machines have been employed for controllably conferring on scanning instruments predetermined scan patterns. They include control moment gyroscopes, reaction wheels, torque motors, reaction control systems, and the like. But rotating unbalanced mass (RUM) devices are a new and efficient way to generate scans in gimballed payloads. RUM devices are superior to previous scanning apparatus, but they require power consuming and frequently complex auxiliary control systems to position and reposition the particular scan pattern relative to a target or a number of targets. Herein the control system is simplified. The most frequently employed method for achieving the various scan patterns is to gimbal the scanning device. Gimbals are suspended in such a way that they can be activated to generate the scan pattern. The suspension means described is for payloads supported in gimbals wherein the payload rotation is restricted by a flex pivot so that the payload oscillates, thereby moving in a scan pattern.

  18. System design of the annular suspension and pointing system /ASPS/

    NASA Technical Reports Server (NTRS)

    Cunningham, D. C.; Gismondi, T. P.; Wilson, G. W.

    1978-01-01

    This paper presents the control system design for the Annular Suspension and Pointing System. Actuator sizing and configuration of the system are explained, and the control laws developed for linearizing and compensating the magnetic bearings, roll induction motor and gimbal torquers are given. Decoupling, feedforward and error compensation for the vernier and gimbal controllers is developed. The algorithm for computing the strapdown attitude reference is derived, and the allowable sampling rates, time delays and quantization of control signals are specified.

  19. Improved Mirnov Magnetic Coils System for the TCABR Tokamak

    NASA Astrophysics Data System (ADS)

    Vannucci, Alvaro; Olschewski, Erich; Kuznetsov, Yuri; Kucinski, Mutsuko; Tadeu Degasperi, Francisco; Araujo, Mauro Sergio; Galvao, Ricardo; Okano, Valdir; Nascimento, Ivan

    2000-10-01

    The Mirnov magnetic coils system for the TCABR was recently reconstructed. The most interesting aspect of this system is that the measured experimental signals already incorporate the influence of the toroidal geometry. This means that the usual fast Fourier transform analysis done on the magnetic experimental data is able to indicate, more precisely and in a straightforward way, the MHD mode contribution to the detected signals during a plasma discharge. The influence of the toroidal geometry on the Fourier analysis of the magnetic signals was investigated by carring a series of simulations, considering the Merezhkin correction expressed only as a function of the inverse of the tokamak aspect ratio (calculated at the position of interest). The results obtained clearly showed the existence of a phase modulation on the Mirnov signals which is not usually considered when the magnetic signals are Fourier analyzed in the frame of cylindrical approximation, that is, by neglecting the existing toroidal effect.

  20. Design of an Inductive Power Transfer System with Flexible Coils for Body-worn Applications

    NASA Astrophysics Data System (ADS)

    Clare, L. R.; Burrow, S. G.; Stark, B. H.; Grabham, N. J.; Beeby, S. P.

    2015-12-01

    This paper describes an IPT (Inductive Power Transfer) system for body worn electronics, and investigates the challenges for an IPT system that arise specifically in this scenario. Principally, these are: highly variable coil coupling through time-varying miss-alignment and coil separation; a requirement that one or both of the coils must be wearable and thus flexible; and proximity to the human body introducing limits on the maximum EM field. The highly variable coupling results in a system that must operate effectively with a large range of received powers, whilst the constraints on the realisation of the coils typically reduce the Q-factor; the human exposure considerations limit both the maximum field strengths that the wearer of a receiver coil might experience, and also the field strengths that a 3rd party might be exposed to, for instance when approaching the transmit coil.

  1. On fault isolation for rail vehicle suspension systems

    NASA Astrophysics Data System (ADS)

    Wei, Xiukun; Jia, Limin; Guo, Kun; Wu, Sheng

    2014-06-01

    Reliability of the railway vehicle suspension system is of critical importance to the safety of the vehicle. It is very desirable to monitor the health condition and the performance degradation of the suspension system online, which offers the important information of the suspension system and is critically important for the condition-based maintenance rather than scheduled maintenance in the future. Advanced fault diagnosis method is one of the most effective means for the health monitoring of the suspension system. In this paper, taking the lateral suspension system as an examcple, the fault isolation issue for different component faults occurring in the suspension system is concerned. The sensor configuration for obtaining the vehicle state information and the mathematical model for the lateral suspension system are presented. Four fault features in the time domain and three fault features in the frequency domain are used for each sensor signal. Three different methods, Dempster-Shafer (D-S) evidence theory, Fisher discrimination analysis (FDA) and support vector machine (SVM) techniques are applied to the fault isolation problem. Simulation study is carried out by means of the professional multi-body simulation tool, SIMPACK. The simulation results show that these methods can isolate the considered component faults effectively with a high accuracy. The D-S evidence-based fault isolation approach outperforms the other two methods.

  2. Study on Dynamic Behaviour of Wishbone Suspension System

    NASA Astrophysics Data System (ADS)

    Kamal, M.; Rahman, M. M.

    2012-09-01

    This paper presents the characteristic model of the wishbone suspension system using the quarter car model approach. Suspension system in an automobile provides vehicle control and passenger comfort by providing isolation from road disturbances. This makes it essential that the detailed behavior of suspension should be known to optimize the performance. A kinetic study is performed using multi body system (MBS) analysis. The dirt road profile is considered as an applied loading. The spring constant, damping coefficient and sprung mass are studied on the performance of the suspension system. It can be observed that the spring constant is inversely related with time required to return to initial position and the amount of deformations. The damping ratio affects the suppression of spring oscillations, beyond a certain limit damping ration has the negligible effect. Sprung mass effected the equilibrium position of the suspension system with a small effect on its oscillation behavior. It is shown that the spring constant, damping ratio and sprung mass are significant parameters to design the suspension system. This study is essential for complete understanding of working of the suspension system and a future study with real geometries.

  3. A Kinematic, Kevlar(registered) Suspension System for an ADR

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.; Jackson, Michael L.; Shirron, Peter J.; Tuttle, James G.

    2003-01-01

    The High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter And Far Infrared Experiment (SAFIRE) will use identical Adiabatic Demagnetization Refrigerators (ADR) to cool their bolometer detectors to 200mK and 100mK, respectively. In order to minimize thermal loads on the salt pill, a Kevlar@ suspension system is used to hold it in place. An innovative, kinematic suspension system is presented. The suspension system is unique in that it consists or two parts that can be assembled and tensioned offline, and later bolted onto the salt pill. The resulting assembly constrains each degree of freedom only once, yielding a kinematic, tensile structure.

  4. Protective link for superconducting coil

    DOEpatents

    Umans, Stephen D.

    2009-12-08

    A superconducting coil system includes a superconducting coil and a protective link of superconducting material coupled to the superconducting coil. A rotating machine includes first and second coils and a protective link of superconducting material. The second coil is operable to rotate with respect to the first coil. One of the first and second coils is a superconducting coil. The protective link is coupled to the superconducting coil.

  5. Automotive suspension control system with self-adjustment feature

    SciTech Connect

    Sugasawa, F.

    1987-06-16

    An automobile vehicle suspension control system is described comprising: a vehicular suspension system with damping characteristics variable at least between a first mode and a second mode, the latter of which provides harder damping characteristics than the first mode, in response to a control signal; a sensor monitoring a preselected suspension control parameter and produces a sensor signal having a value indicative of a vehicular driving condition represented by the preselected suspension control parameter; first means comparing the sensor signal value with a threshold value and producing the control signal ordering the vehicular suspension system from first mode to second mode when the sensor signal value is greater than the threshold value; second means for counting occurrences of the control signal orders the vehicular suspension system from first mode to second mode and produces a counter signal with a value representative of the counted value; and third means detects counter signal when it exceeds a first reference value. In such cases it modifies the threshold value so as to lower the sensitivity of suspension control to the sensor signal.

  6. Anharmonic Oscillations of a Spring-Magnet System inside a Magnetic Coil

    ERIC Educational Resources Information Center

    Ladera, Celso L.; Donoso, Guillermo

    2012-01-01

    We consider the nonlinear oscillations of a simple spring-magnet system that oscillates in the magnetic field of an inductive coil excited with a dc current. Using the relations for the interaction of a coil and a magnet we obtain the motion equation of the system. The relative strengths of the terms of this equation can be adjusted easily by…

  7. Anharmonic Oscillations of a Spring-Magnet System inside a Magnetic Coil

    ERIC Educational Resources Information Center

    Ladera, Celso L.; Donoso, Guillermo

    2012-01-01

    We consider the nonlinear oscillations of a simple spring-magnet system that oscillates in the magnetic field of an inductive coil excited with a dc current. Using the relations for the interaction of a coil and a magnet we obtain the motion equation of the system. The relative strengths of the terms of this equation can be adjusted easily by…

  8. Analysis of Train Suspension System Using MR dampers

    NASA Astrophysics Data System (ADS)

    RamaSastry, DVA; Ramana, K. V.; Mohan Rao, N.; Siva Kumar, SVR; Priyanka, T. G. L.

    2016-09-01

    This paper deals with introducing MR dampers to the Train Suspension System for improving the ride comfort of the passengers. This type of suspension system comes under Semi-active suspension system which utilizes the properties of MR fluid to damp the vibrations. In case of high speed trains, the coach body is subjected to vibrations due to vertical displacement, yaw and pitch movements. When the body receives these disturbances from the ground,the transmission of vibrations to the passenger increases which affect the ride comfort. In this work, the equations of motion of suspension system are developed for both conventional passive system and semi-active system and are modelled in Matlab/Simulink and analysis has been carried out. The passive suspension system analysis shows that it is taking more time to damp the vibrations and at the same time the transmissibility of vibrations is more.Introducing MR dampers,vertical and angular displacements of the body are computed and compared. The results show that the introduction of MR dampers into the train suspension system improves ride comfort.

  9. Active seat suspension for a small vehicle: considerations for control system including observer

    NASA Astrophysics Data System (ADS)

    Katsumata, Hiroyuki; Shiino, Hiroshi; Oshinoya, Yasuo; Ishibashi, Kazuhisa; Ozaki, Koichi; Ogino, Hirohiko

    2007-12-01

    We have examined the improvement of ride quality and the reduction of riding fatigue brought about by the active control of the seat suspension of small vehicles such as one-seater electric automobiles. A small active seat suspension, which is easy to install, was designed and manufactured for one-seater electric automobiles. For the actuator, a maintenance-free voice coil motor used as a direct drive was adopted. For fundamental considerations, we designed a one-degree-of-freedom model for the active seat suspension system. Then, we designed a disturbance cancellation control system that includes the observer for a two-degree-of-freedom model. In an actual driving test, a test road, in which the concavity and convexity of an actual road surface were simulated using hard rubber, was prepared and the control performance of vertical vibrations of the seat surface during driving was examined. As a result, in comparison with the one-degree-of-freedom control system, it was confirmed that the control performance was improved by the two-degree-of-freedom control system that includes the observer.

  10. View of Powell Library main reading room ceiling; suspension system ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Powell Library main reading room ceiling; suspension system above ceiling showing close-up connection. - University of California Los Angeles, Powell Library, Westwood, Los Angeles, Los Angeles County, CA

  11. 46. View looking NW towards lower Manhattan showing suspension system ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. View looking NW towards lower Manhattan showing suspension system and superstructure. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  12. A novel and inexpensive digital system for eye movement recordings using magnetic scleral search coils.

    PubMed

    Eibenberger, Karin; Eibenberger, Bernhard; Roberts, Dale C; Haslwanter, Thomas; Carey, John P

    2016-03-01

    After their introduction by Robinson (IEEE Trans Biomed Eng 10:137-145, 1963), magnetic scleral search coils quickly became an accepted standard for precise eye movement recordings. While other techniques such as video-oculography or electro-oculography may be more suitable for routine applications, search coils still provide the best low-noise and low-drift characteristics paired with the highest temporal and spatial resolution. The problem with search coils is that many research laboratories still have their large and expensive coil systems installed and are acquiring eye movement data with old, analog technology. Typically, the number of recording channels is limited and modifications to an existing search coil system can be difficult. We propose a system that allows to retro-fit an existing analog search coil system to become a digital recording system. The system includes digital data acquisition boards and a reference coil as the hardware part, receiver software, and a new calibration method. The circuit design has been kept simple and robust, and the proposed software calibration allows the calibration of a single coil within a few seconds.

  13. The Structures of Coiled-Coil Domains from Type III Secretion System Translocators Reveal Homology to Pore-Forming Toxins

    SciTech Connect

    Barta, Michael L.; Dickenson, Nicholas E.; Patil, Mrinalini; Keightley, Andrew; Wyckoff, Gerald J.; Picking, William D.; Picking, Wendy L.; Geisbrecht, Brian V.

    2012-03-26

    Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. The Shigella type III secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 {angstrom} and 2.8 {angstrom} limiting resolution, respectively. These newly identified domains are composed of extended-length (114 {angstrom} in IpaB and 71 {angstrom} in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably, colicin Ia. This suggests that these mechanistically separate and functionally distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events.

  14. THE STRUCTURES OF COILED-COIL DOMAINS FROM TYPE THREE SECRETION SYSTEM TRANSLOCATORS REVEAL HOMOLOGY TO PORE-FORMING TOXINS

    PubMed Central

    Barta, Michael L.; Dickenson, Nicholas E.; Patil, Mrinalini; Keightley, Andrew; Wyckoff, Gerald J.; Picking, William D.; Picking, Wendy L.; Geisbrecht, Brian V.

    2012-01-01

    Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SS) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) which is responsible for over one million deaths per year. The Shigella type III secretion apparatus (T3SA) is comprised of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 Å and 2.8 Å limiting resolution, respectively. These newly identified domains are comprised of extended length (114 Å in IpaB and 71 Å in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably colicin Ia. This suggests that these mechanistically-separate and functionally-distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events. PMID:22321794

  15. Parametric system studies of candidate TF coil system options for the Tokamak Fusion Core Experiment (TFCX)

    SciTech Connect

    Reiersen, W.T.; Flanagan, C.A.; Miller, J.B.

    1983-01-01

    System studies were performed to determine the sensitivity of hybrid and superconducting toroidal field (TF) coil system options to maximum field at the TF coil and to field enhancement due to resistive insert coils. The studies were performed using Tokamak Fusion Core Experiment (TFCX) design assumptions, guidelines, and criteria and involved iterative execution of the Fusion Engineering Design Center (FEDC) systems code, magnetohydrodynamics (MHD) equilibrium code, and EFFI (a code to evaluate magnetic field strength). The results indicate that for TFCX with no minimum wall loading specified, a design point chosen solely on the basis of cost would likely be in the low-field region of design space where the cost advantage of hybrids is least apparent. However, as the desired neutron wall loading increases, the hybrid option suggests an increasing cost advantage over the all-superconducting option; this cost advantage is countered by increased complexity in design - particularly in assembly and maintenance.

  16. Superconducting electromagnets for large wind tunnel magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.; Scurlock, R. G.; Wu, Y. Y.; Goodyer, M. J.; Balcerek, K.; Eskins, J.; Britcher, C. P.

    1984-01-01

    A superconducting electromagnetic suspension and balance system for an 8 x 8-ft, Mach 0.9 wind tunnel is presented. The system uses a superconducting solenoid as a model core 70 cm long and with a 11.5 cm OD, and a combination of permanent magnet material in the model wings to produce the required roll torque. The design, which uses an integral cold structure rather than separate cryostats for mounting all control magnets, has 14 external magnets, including 4 racetrack-shaped roll coils. Helium capacity of the system is 3.0 to 3.5 l with idling boiloff rate predicted at 0.147 to 0.2 l/h. The improvements yielded a 50-percent reduction in the system size, weight, and cost.

  17. Superconducting electromagnets for large wind tunnel magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.; Scurlock, R. G.; Wu, Y. Y.; Goodyer, M. J.; Balcerek, K.; Eskins, J.; Britcher, C. P.

    1984-01-01

    A superconducting electromagnetic suspension and balance system for an 8 x 8-ft, Mach 0.9 wind tunnel is presented. The system uses a superconducting solenoid as a model core 70 cm long and with a 11.5 cm OD, and a combination of permanent magnet material in the model wings to produce the required roll torque. The design, which uses an integral cold structure rather than separate cryostats for mounting all control magnets, has 14 external magnets, including 4 racetrack-shaped roll coils. Helium capacity of the system is 3.0 to 3.5 l with idling boiloff rate predicted at 0.147 to 0.2 l/h. The improvements yielded a 50-percent reduction in the system size, weight, and cost.

  18. Array high-sensitivity room temperature coil system for SNMR detection in shallow depth

    NASA Astrophysics Data System (ADS)

    Lin, Tingting; Xie, Kunyu; Zhang, Siyuan; Zhao, Jing; Lin, Jun

    2017-01-01

    The noninvasive method of surface nuclear magnetic resonance (SNMR) is a geophysical technique that is directly sensitive to hydrogen protons, besides it can exploit the NMR phenomenon for a quantitative determination of the subsurface groundwater distribution. Traditionally, SNMR utilizes large surface coils for both transmitting excitation pulses and recording the groundwater response. While, in recent research, a low Tc-SQUIDs is taken as a new sensor to replace the large receiving coil (Rx), which performing the best sensitivity for the shallow depth. Nevertheless, SQUID is with the problems of flux trapping and operational difficulties. In this paper, we introduce a room temperature coil system. A Cu coil with diameter of 1 m and a low noise preamplifier was systematically investigated and reached a sensitivity of 0.2fT/Hz1/2.Four preamplifiers are chosen for optimizing the pickup coils. The resolution studies for the array coil systems were performed, and the optimum distance between the adjacent pickup coils to achieve a better experimental results especially for the shallow depth. Our study enable the further use of the room temperature coil for SNMR shallow depth detections.

  19. Optical position measurement for a Large Gap Magnetic Suspension System

    NASA Technical Reports Server (NTRS)

    Welch, Sharon S.; Shelton, Kevin J.; Clemmons, James I.

    1991-01-01

    This paper describes the design of an optical position measurement system which is being built as part of the NASA Langley Large Gap Magnetic Suspension System (LGMSS). The LGMSS is a five degree-of-freedom, large-gap magnetic suspension system which is being built for Langley Research Center as part of the Advanced Controls Test Facility (ACTF). The LGMSS consists of a planar array of electromagnets which levitate and position a cylindrically shaped model containing a permanent magnet core. The optical position measurement system provides information on the location and orientation of the model to the LGMSS control system to stabilize levitation of the model.

  20. Magnetic energy coupling system based on micro-electro-mechanical system coils

    NASA Astrophysics Data System (ADS)

    Li, Xiuhan; Yuan, Quan; Yang, Tianyang; Liu, Jian; Zhang, Haixia

    2012-04-01

    In this paper, a high efficiency wireless energy transfer system based on MEMS coils is first developed. The permanent magnetic core used in the transmitting coil can not only enhance the magnetic flux but also applies a strong and uniform magnetic field distribution around the core. Ansoft hfss is then used to analyze the performance of two coupling coils designed to be resonated at the same frequency. The distribution of magnetic field strength and coupling efficiency is modeled and characterized. High-performance bio-compatible MEMS coils were fabricated on a glass wafer by thick glue photolithography and electroplating technique. We measured a peak value of energy transfer at the resonant frequency of 23 MHz, and the coupling efficiency is higher than 10% within the distance of 10-20 cm by sweeping frequencies from 1 MHz to 200 MHz. Experiments also show that the resonant coupling efficiency is not much affected by the relative position of the two coils in a large range.

  1. A Large Motion Suspension System for Simulation of Orbital Deployment

    NASA Technical Reports Server (NTRS)

    Straube, T. M.; Peterson, L. D.

    1994-01-01

    This paper describes the design and implementation of a vertical degree of freedom suspension system which provides a constant force off-load condition to counter gravity over large displacements. By accommodating motions up to one meter for structures weighing up to 100 pounds, the system is useful for experiments which simulate the on-orbit deployment of spacecraft components. A unique aspect of this system is the combination of a large stroke passive off-load device augmented by electromotive torque actuated force feedback. The active force feedback has the effect of reducing breakaway friction by an order of magnitude over the passive system alone. The paper describes the development of the suspension hardware and the feedback control algorithm. Experiments were performed to verify the suspensions system's ability to provide a gravity off-load as well as its effect on the modal characteristics of a test article.

  2. Development of an air pneumatic suspension system for transtibial prostheses.

    PubMed

    Pirouzi, Gholamhossein; Abu Osman, Noor Azuan; Oshkour, Azim Ataollahi; Ali, Sadeeq; Gholizadeh, Hossein; Abas, Wan A B Wan

    2014-09-09

    The suspension system and socket fitting of artificial limbs have major roles and vital effects on the comfort, mobility, and satisfaction of amputees. This paper introduces a new pneumatic suspension system that overcomes the drawbacks of current suspension systems in donning and doffing, change in volume during daily activities, and pressure distribution in the socket-stump interface. An air pneumatic suspension system (APSS) for total-contact sockets was designed and developed. Pistoning and pressure distribution in the socket-stump interface were tested for the new APSS. More than 95% of the area between each prosthetic socket and liner was measured using a Tekscan F-Scan pressure measurement which has developed matrix-based pressure sensing systems. The variance in pressure around the stump was 8.76 kPa. APSS exhibits less pressure concentration around the stump, improved pressure distribution, easy donning and doffing, adjustability to remain fitted to the socket during daily activities, and more adaptability to the changes in stump volume. The volume changes were adjusted by utility of air pressure sensor. The vertical displacement point and reliability of suspension were assessed using a photographic method. The optimum pressure in every level of loading weight was 55 kPa, and the maximum displacement was 6 mm when 90 N of weight was loaded.

  3. Development of an Air Pneumatic Suspension System for Transtibial Prostheses

    PubMed Central

    Pirouzi, Gholamhossein; Osman, Noor Azuan Abu; Oshkour, Azim Ataollahi; Ali, Sadeeq; Gholizadeh, Hossein; Wan Abas, Wan A. B.

    2014-01-01

    The suspension system and socket fitting of artificial limbs have major roles and vital effects on the comfort, mobility, and satisfaction of amputees. This paper introduces a new pneumatic suspension system that overcomes the drawbacks of current suspension systems in donning and doffing, change in volume during daily activities, and pressure distribution in the socket-stump interface. An air pneumatic suspension system (APSS) for total-contact sockets was designed and developed. Pistoning and pressure distribution in the socket-stump interface were tested for the new APSS. More than 95% of the area between each prosthetic socket and liner was measured using a Tekscan F-Scan pressure measurement which has developed matrix-based pressure sensing systems. The variance in pressure around the stump was 8.76 kPa. APSS exhibits less pressure concentration around the stump, improved pressure distribution, easy donning and doffing, adjustability to remain fitted to the socket during daily activities, and more adaptability to the changes in stump volume. The volume changes were adjusted by utility of air pressure sensor. The vertical displacement point and reliability of suspension were assessed using a photographic method. The optimum pressure in every level of loading weight was 55 kPa, and the maximum displacement was 6 mm when 90 N of weight was loaded. PMID:25207872

  4. A Magnetic Resonance (MR) Microscopy System using a Microfluidically Cryo-Cooled Planar Coil

    PubMed Central

    Koo, Chiwan; Godley, Richard F.; Park, Jaewon; McDougall, Mary P.; Wright, Steven M.; Han, Arum

    2011-01-01

    We present the development of a microfluidically cryo-cooled planar coil for magnetic resonance (MR) microscopy. Cryogenically cooling radiofrequency (RF) coils for magnetic resonance imaging (MRI) can improve the signal to noise ratio (SNR) of the experiment. Conventional cryostats typically use a vacuum gap to keep samples to be imaged, especially biological samples, at or near room temperature during cryo-cooling. This limits how close a cryo-cooled coil can be placed to the sample. At the same time, a small coil-to-sample distance significantly improves the MR imaging capability due to the limited imaging depth of planar MR microcoils. These two conflicting requirements pose challenges to the use of cryo-cooling in MR microcoils. The use of a microfluidic based cryostat for localized cryo-cooling of MR microcoils is a step towards eliminating these constraints. The system presented here consists of planar receive-only coils with integrated cryo-cooling microfluidic channels underneath, and an imaging surface on top of the planar coils separated by a thin nitrogen gas gap. Polymer microfluidic channel structures fabricated through soft lithography processes were used to flow liquid nitrogen under the coils in order to cryo-cool the planar coils to liquid nitrogen temperature (−196°C). Two unique features of the cryo-cooling system minimize the distance between the coil and the sample: 1) The small dimension of the polymer microfluidic channel enables localized cooling of the planar coils, while minimizing thermal effects on the nearby imaging surface. 2) The imaging surface is separated from the cryo-cooled planar coil by a thin gap through which nitrogen gas flows to thermally insulate the imaging surface, keeping it above 0°C and preventing potential damage to biological samples. The localized cooling effect was validated by simulations, bench testing, and MR imaging experiments. Using this cryo-cooled planar coil system inside a 4.7 Tesla MR system

  5. A magnetic resonance (MR) microscopy system using a microfluidically cryo-cooled planar coil.

    PubMed

    Koo, Chiwan; Godley, Richard F; Park, Jaewon; McDougall, Mary P; Wright, Steven M; Han, Arum

    2011-07-07

    We present the development of a microfluidically cryo-cooled planar coil for magnetic resonance (MR) microscopy. Cryogenically cooling radiofrequency (RF) coils for magnetic resonance imaging (MRI) can improve the signal to noise ratio (SNR) of the experiment. Conventional cryostats typically use a vacuum gap to keep samples to be imaged, especially biological samples, at or near room temperature during cryo-cooling. This limits how close a cryo-cooled coil can be placed to the sample. At the same time, a small coil-to-sample distance significantly improves the MR imaging capability due to the limited imaging depth of planar MR microcoils. These two conflicting requirements pose challenges to the use of cryo-cooling in MR microcoils. The use of a microfluidic based cryostat for localized cryo-cooling of MR microcoils is a step towards eliminating these constraints. The system presented here consists of planar receive-only coils with integrated cryo-cooling microfluidic channels underneath, and an imaging surface on top of the planar coils separated by a thin nitrogen gas gap. Polymer microfluidic channel structures fabricated through soft lithography processes were used to flow liquid nitrogen under the coils in order to cryo-cool the planar coils to liquid nitrogen temperature (-196 °C). Two unique features of the cryo-cooling system minimize the distance between the coil and the sample: (1) the small dimension of the polymer microfluidic channel enables localized cooling of the planar coils, while minimizing thermal effects on the nearby imaging surface. (2) The imaging surface is separated from the cryo-cooled planar coil by a thin gap through which nitrogen gas flows to thermally insulate the imaging surface, keeping it above 0 °C and preventing potential damage to biological samples. The localized cooling effect was validated by simulations, bench testing, and MR imaging experiments. Using this cryo-cooled planar coil system inside a 4.7 Tesla MR system

  6. Optimal Design of Litz Wire Coils With Sandwich Structure Wirelessly Powering an Artificial Anal Sphincter System.

    PubMed

    Ke, Lei; Yan, Guozheng; Yan, Sheng; Wang, Zhiwu; Li, Xiaoyang

    2015-07-01

    Transcutaneous energy transfer system (TETS) is widely used to energize implantable biomedical devices. As a key part of the TETS, a pair of applicable coils with low losses, high unloaded Q factor, and strong coupling is required to realize an efficient TETS. This article presents an optimal design methodology of planar litz wire coils sandwiched between two ferrite substrates wirelessly powering a novel mechanical artificial anal sphincter system for treating severe fecal incontinence, with focus on the main parameters of the coils such as the wire diameter, number of turns, geometry, and the properties of the ferrite substrate. The theoretical basis of optimal power transfer efficiency in an inductive link was analyzed. A set of analytical expressions are outlined to calculate the winding resistance of a litz wire coil on ferrite substrate, taking into account eddy-current losses, including conduction losses and induction losses. Expressions that describe the geometrical dimension dependence of self- and mutual inductance are derived. The influence of ferrite substrate relative permeability and dimensions is also considered. We have used this foundation to devise an applicable coil design method that starts with a set of realistic constraints and ends with the optimal coil pair geometries. All theoretical predictions are verified with measurements using different types of fabricated coils. The results indicate that the analysis is useful for optimizing the geometry design of windings and the ferrite substrate in a sandwich structure as part of which, in addition to providing design insight, allows speeding up the system efficiency-optimizing design process.

  7. Feasibility study of a novel pressure recovery system for CO2-COIL based on chemical absorption

    NASA Astrophysics Data System (ADS)

    Li, Qingwei; Jin, Yuqi; Geng, Zicai; Li, Yongzhao; Zhang, Yuelong; Sang, Fengting

    2015-02-01

    A chemical oxygen-iodine laser (COIL) is an electronic transition, low pressure, high throughput system. The use of this laser demands a suitable pressure recovery system. This paper proposed a novel pressure recovery system based on chemical absorption and the feasibility for COIL with CO2 as buffer gas (CO2-COIL) was investigated. The novel pressure recovery system works by chemisorbing the CO2-COIL effluents into two fixed-beds maintained at initial temperature of around 293-323K. Compared with the cryosorption system for N2-COIL based on physical absorption, the novel chemisorptions based pressure recovery system has a simpler logistics and a shorter run-to-run preparation time. Two kinds of solid chemo-sorbents were designed and synthesized. One was used for chemisorbing the oxidizing gases such as O2 ,Cl2 and I2, another was used for chemisorbing the acidic gas such as CO2. The capacities of the two sorbents were measured to be 3.12 mmol(O2)/g and 3.84 mmol (CO2) /g, respectively. It indicated that the synthesized sorbents could effectively chemosorb the CO2-COIL effluents. Secondly, analog test equipment was set up and used to study the feasibility of the novel pressure recovery system used for CO2-COIL. The test results showed that the novel pressure recovery system could maintain the pressure under 6 Torr for tens seconds under the continuous gas flow. It showed that the novel pressure recovery system for CO2-COIL based on chemical absorption is feasible.

  8. Transfemoral prosthesis suspension systems: a systematic review of the literature.

    PubMed

    Gholizadeh, Hossein; Abu Osman, Noor Azuan; Eshraghi, Arezoo; Ali, Sadeeq

    2014-09-01

    The purpose of this study was to find the scientific evidence pertaining to various transfemoral suspension systems to provide selection criteria for clinicians. To this end, databases of PubMed, Web of Science, and ScienceDirect were explored. The following key words, as well as their combinations and synonyms, were used for the search: transfemoral prosthesis, prosthetic suspension, lower limb prosthesis, above-knee prosthesis, prosthetic liner, transfemoral, and prosthetic socket. The study design, research instrument, sampling method, outcome measures, and protocols of articles were reviewed. On the basis of the selection criteria, 16 articles (11 prospective studies and 5 surveys) were reviewed. The main causes of reluctance to prosthesis, aside from energy expenditure, were socket-related problems such as discomfort, perspiration, and skin problems. Osseointegration was a suspension option, yet it is rarely applied because of several drawbacks, such as extended rehabilitation process, risk for fracture, and infection along with excessive cost. In conclusion, no clinical evidence was found as a "standard" system of suspension and socket design for all transfemoral amputees. However, among various suspension systems for transfemoral amputees, the soft insert or double socket was favored by most users in terms of function and comfort.

  9. Novel design for suspension array detection system

    NASA Astrophysics Data System (ADS)

    Xu, Guoxiong; Shi, Yan; Ni, Xuxiang; Lu, Zukang

    2005-01-01

    This paper presents a novel method for establishing a two-dimensional laminar fluidic suspension array which is analyzed by using time delay integration (TDI) CCD imaging technology in parallel. The method will make suspension array technology (SAT) bear high throughput as well as its flexibility. Basically, bioassays are conducted on the surface of fluorescent-dyed beads. With each bead set (i.e., multiple beads with the same fluorescent signature) having a slightly different fluorescent signature, probes are first attached to a particular bead set and then hybridized with labeled samples or targets. Two different kinds of encoding dyes are excited by red laser (635 nm, 20mw), their emission wave length are 660nm, 720nm, respectively. Fluorescent dye of reporter molecules was excited by green laser (532nm, 20mw), emitted at 580 nm. The liquid sample was pumped into micro-reservoir by a linear motor. As the velocity of liquid sample is so slow (10mm/s) it is easy to form a laminar fluidic field in the middle of the micro-reservoir. In the direction of laser propagation the size of reservoir is 0.1mm so the laminar liquid can be treated as a two-dimensional fluidic plane. The size of detection area depends on size of micro-sphere and CCD imaging area. The three kinds of fluorescence signals were focused by a lens and then split by mirrors. Fluorescence pass through three band-pass filters (+/-20nm) before collected by three TDI-CCDs respectively. With these high-quality filters the cross-talk between signals was diminished significantly. The analysis speed is about 2x103 micro-spheres per second, which is much higher than that obtained from currently cytometry method (about 102 micro-spheres to the same size micro-spheres).

  10. High performance 3-coil wireless power transfer system for the 512-electrode epiretinal prosthesis.

    PubMed

    Zhao, Yu; Nandra, Mandheerej; Yu, Chia-Chen; Tai, Yu-chong

    2012-01-01

    The next-generation retinal prostheses feature high image resolution and chronic implantation. These features demand the delivery of power as high as 100 mW to be wireless and efficient. A common solution is the 2-coil inductive power link, used by current retinal prostheses. This power link tends to include a larger-size extraocular receiver coil coupled to the external transmitter coil, and the receiver coil is connected to the intraocular electrodes through a trans-sclera trans-choroid cable. In the long-term implantation of the device, the cable may cause hypotony (low intraocular pressure) and infection. However, when a 2-coil system is constructed from a small-size intraocular receiver coil, the efficiency drops drastically which may induce over heat dissipation and electromagnetic field exposure. Our previous 2-coil system achieved only 7% power transfer. This paper presents a fully intraocular and highly efficient wireless power transfer system, by introducing another inductive coupling link to bypass the trans-sclera trans-choroid cable. With the specific equivalent load of our customized 512-electrode stimulator, the current 3-coil inductive link was measured to have the overall power transfer efficiency around 36%, with 1-inch separation in saline. The high efficiency will favorably reduce the heat dissipation and electromagnetic field exposure to surrounding human tissues. The effect of the eyeball rotation on the power transfer efficiency was investigated as well. The efficiency can still maintain 14.7% with left and right deflection of 30 degree during normal use. The surgical procedure for the coils' implantation into the porcine eye was also demonstrated.

  11. 54. INTERIOR OF APRON SUSPENSION STRUCTURE SHOWING APRON COUNTERWEIGHT SYSTEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    54. INTERIOR OF APRON SUSPENSION STRUCTURE SHOWING APRON COUNTERWEIGHT SYSTEM OF CABLES AND PULLEYS ABOVE BRIDGE NOS. 12 AND 11. LOOKING NORTH. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

  12. Asymptotic behavior of coupled linear systems modeling suspension bridges

    NASA Astrophysics Data System (ADS)

    Dell'Oro, Filippo; Giorgi, Claudio; Pata, Vittorino

    2015-06-01

    We consider the coupled linear system describing the vibrations of a string-beam system related to the well-known Lazer-McKenna suspension bridge model. For ɛ > 0 and k > 0, the decay properties of the solution semigroup are discussed in dependence of the nonnegative parameters γ and h, which are responsible for the damping effects.

  13. Disturbance observer based sliding mode control of active suspension systems

    NASA Astrophysics Data System (ADS)

    Deshpande, Vaijayanti S.; Mohan, B.; Shendge, P. D.; Phadke, S. B.

    2014-05-01

    In this paper, a novel scheme to reduce the acceleration of the sprung mass, used in combination with sliding mode control, is proposed. The proposed scheme estimates the effects of the uncertain, nonlinear spring and damper, load variation and the unknown road disturbance. The controller needs the states of sprung mass only, obviating the need to measure the states of the unsprung mass. The ultimate boundedness of the overall suspension system is proved. The efficacy of the method is verified through simulations for three different types of road profiles and load variation and the scheme is validated on an experimental setup. The results are compared with passive suspension system.

  14. A Magnetic Suspension and Excitation System for Spin Vibration Testing of Turbomachinery Blades

    NASA Technical Reports Server (NTRS)

    Johnson, Dexter; Brown, Gerald V.; Mehmed, Oral

    1998-01-01

    The Dynamic Spin Rig (DSR) is used to perform vibration tests of turbomachinery blades and components under spinning conditions in a vacuum. A heteropolar radial active magnetic bearing was integrated into the DSR to provide non-contact magnetic suspension and mechanical excitation of the rotor to induce turbomachinery blade vibrations. The magnetic bearing replaces one of the two existing conventional radial ball bearings. Prior operation of the DSR used two voice-coil type linear electromagnetic shakers which provided axial excitation of the rotor. The new magnetic suspension and excitation system has provided enhanced testing capabilities. Tests were performed at high rotational speeds for longer duration and higher vibration amplitudes. Some characteristics of the system include magnetic bearing stiffness values up to 60,000 lb./in., closed loop control bandwidth around 500 Hz, and multi-directional radial excitation of the rotor. This paper reports on the implementation and operation of this system and presents some test results using this system.

  15. Apparatus and method for reducing inductive coupling between levitation and drive coils within a magnetic propulsion system

    DOEpatents

    Post, Richard F.

    2001-01-01

    An apparatus and method is disclosed for reducing inductive coupling between levitation and drive coils within a magnetic levitation system. A pole array has a magnetic field. A levitation coil is positioned so that in response to motion of the magnetic field of the pole array a current is induced in the levitation coil. A first drive coil having a magnetic field coupled to drive the pole array also has a magnetic flux which induces a parasitic current in the levitation coil. A second drive coil having a magnetic field is positioned to attenuate the parasitic current in the levitation coil by canceling the magnetic flux of the first drive coil which induces the parasitic current. Steps in the method include generating a magnetic field with a pole array for levitating an object; inducing current in a levitation coil in response to motion of the magnetic field of the pole array; generating a magnetic field with a first drive coil for propelling the object; and generating a magnetic field with a second drive coil for attenuating effects of the magnetic field of the first drive coil on the current in the levitation coil.

  16. Enhancing the design of a superconducting coil for magnetic energy storage systems

    NASA Astrophysics Data System (ADS)

    Indira, Gomathinayagam; UmaMaheswaraRao, Theru; Chandramohan, Sankaralingam

    2015-01-01

    Study and analysis of a coil for Superconducting Magnetic Energy Storage (SMES) system is presented in this paper. Generally, high magnetic flux density is adapted in the design of superconducting coil of SMES to reduce the size of the coil and to increase its energy density. With high magnetic flux density, critical current density of the coil is degraded and so the coil is wound with High Temperature Superconductors (HTS) made of different materials. A comparative study is made to emphasize the relationship between the energy storage and length of the coil wound by Bi2223, SF12100, SCS12100 and YBCO tapes. Recently for the construction of HTS magnets, YBCO tapes have been used. Simulation models for various designs have been developed to analyze the magnetic field distribution for the optimum design of energy storage. The design which gives the maximum stored energy in the coil has been used with a certain length of second-generation HTS. The performance analysis and the results of comparative study are done.

  17. An Overview Of The ITER In-Vessel Coil Systems

    SciTech Connect

    Heitzenroeder, P J; Chrzanowski, J H; Dahlgren, F; Hawryluk, R J; Loesser, G D; Neumeyer, C; Mansfield, C; Smith, J P; Schaffer, M; Humphreys, D; Cordier, J J; Campbell, D; Johnson, G A; Martin, A; Rebut, P H; Tao, J O; Fogarty, P J; Nelson, B E; Reed, R P

    2009-09-24

    ELM mitigation is of particular importance in ITER in order to prevent rapid erosion or melting of the divertor surface, with the consequent risk of water leaks, increased plasma impurity content and disruptivity. Exploitable "natural" small or no ELM regimes might yet be found which extrapolate to ITER but this cannot be depended upon. Resonant Magnetic Perturbation has been added to pellet pacing as a tool for ITER to mitigate ELMs. Both are required, since neither method is fully developed and much work remains to be done. In addition, in-vessel coils enable vertical stabilization and RWM control. For these reasons, in-vessel coils (IVCs) are being designed for ITER to provide control of Edge Localized Modes (ELMs) in addition to providing control of moderately unstable resistive wall modes (RWMs) and the vertical stability (VS) of the plasma.

  18. Process analytical approaches for the coil-to-globule transition of poly(N-isopropylacrylamide) in a concentrated aqueous suspension.

    PubMed

    Werner, Peter; Münzberg, Marvin; Hass, Roland; Reich, Oliver

    2017-01-01

    The coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM) microgel particles suspended in water has been investigated in situ as a function of heating and cooling rate with four optical process analytical technologies (PAT), sensitive to structural changes of the polymer. Photon Density Wave (PDW) spectroscopy, Focused Beam Reflectance Measurements (FBRM), turbidity measurements, and Particle Vision Microscope (PVM) measurements are found to be powerful tools for the monitoring of the temperature-dependent transition of such thermo-responsive polymers. These in-line technologies allow for monitoring of either the reduced scattering coefficient and the absorption coefficient, the chord length distribution, the reflected intensities, or the relative backscatter index via in-process imaging, respectively. Varying heating and cooling rates result in rate-dependent lower critical solution temperatures (LCST), with different impact of cooling and heating. Particularly, the data obtained by PDW spectroscopy can be used to estimate the thermodynamic transition temperature of PNIPAM for infinitesimal heating or cooling rates. In addition, an inverse hysteresis and a reversible building of micrometer-sized agglomerates are observed for the PNIPAM transition process.

  19. US Marine Corps assault amphibious vehicle suspension system analysis

    SciTech Connect

    Hammonds, C.J.; Jones, J.K.; Mayhall, J.A.; Williamson, D.E.

    1988-11-01

    In response to a request from the US Marine Corps (USMC), the Oak Ridge National Laboratory investigated a problem with the suspension system of the assault amphibious vehicle (AAV), Personnel Model 7A1. In the course of the investigation, drawings of the AAV and field survey data on bearing failures provided by VSE Corporation were used. The analysis approach taken was to model the suspension system and the vehicle hull and support structure using finite element techniques. This provided stress and deflection information for the system. To determine the loads imparted to the system as the AAV traversed terrain features, a dynamics model was developed to provide loads to the finite element analysis (FEA). Because the primary indication of a problem was frequent suspension-system bearing failure, an analysis of the suspension-system bearings was conducted. Finally, to check the accuracy of the models and to provide actual load data for bearing analysis, an instrumented AAV was tested over a surveyed course at Camp Pendleton, California. Initially the dynamics model assumed the interface between the hull and the suspension system to be fixed. Later improvements incorporating the flexibility of the vehicle hull into the analysis by linking the two models resulted in improved accuracy. Actual measurements of the front road-arm displacement and vertical acceleration of the chassis are compared with predictions from the model. The correlation is quite good and indicates that the model can accurately predict the dynamic load on each road wheel for input into finite element analyses. The dynamics model can be expanded to study the effects of adding weight to the vehicle, traversing other terrains, or evaluating inputs such as weapons firing or drop tests. 7 refs., 75 figs., 10 tabs.

  20. A 32-channel coil system for MR vessel wall imaging of intracranial and extracranial arteries at 3T.

    PubMed

    Hu, Xiaoqing; Li, Ye; Zhang, Lei; Zhang, Xiaoliang; Liu, Xin; Chung, Yiu-Cho

    2017-02-01

    To develop a RF coil system for joint imaging of intracranial and extracranial arterial vessel wall at 3T. The coil system consists of a 24-channel head coil combined with an 8-channel carotid coil. It is compared with a standard coil configuration (12-channel head coil+4-channel neck coil+8-channel carotid coil) for SNR and g-factors in phantoms and healthy volunteers. The clinical relevance of the proposed coil system is also evaluated in patients. In phantom experiments, the SNR of the proposed coil system is 53% higher than the maximum SNR of the standard coil configuration at the center of the phantom which usually corresponds to the intracranial region of the head. The g-factors of the proposed coil system in the sagittal plane are lower than the standard coil configuration (by 10.8% and 26.6% for R=2 and 4 respectively) in the same experiment. In healthy volunteer experiments, 55% of the pixels have SNR above 100 for the proposed coil system, which is 33% more than that of the standard coil configuration. The maximum g-factors in the standard configuration are higher than those from the new coil design by 12% at R=2 and up to 36% at R=4 in the sagittal plane. In patients, in-vivo intracranial and extracranial arterial wall images at an isotropic spatial resolution of 0.6mm can be acquired using the proposed coil system. Plaques are well depicted from the images. The performance of the proposed coil set is superior to the standard coil configuration, providing high SNR, low g-factor and good spatial coverage needed for simultaneous high resolution imaging of intracranial and extracranial arterial walls. Images acquired in 7.6min using the proposed coil system can achieve an isotropic spatial resolution of 0.6mm and can be used to depict plaques on the intracranial and extracranial arterial walls in patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. The design and performance of a geothermal heat pump system using horizontal sub-slab ground coils

    SciTech Connect

    Jensen, J.; Den Braven, K.

    1999-07-01

    The most significant disadvantage of geothermal or ground-coupled heat pumps (GHPs or GCHPs) is the relatively high cost of installing the ground coil. Installation costs can be reduced by effectively utilizing the soil under slab floors in residential installations, taking advantage of the excavation required for the house foundation and other features. A GHP system with six ground coils was installed in a residence on Lake Coeur d'Alene in northern Idaho. Four horizontal sub-slab ground coils were installed beneath the slab floor of the house and garage. Another ground coil was wrapped around the residential septic tank. A sixth coil was placed in a trench outside the basement wall in a spiral-coiled configuration. The primary purpose of this research was to design and install a geothermal heat pump system using different designs of horizontal sub-slab coils, and to compare the performance of the different types of coil placement. Coils that are placed deeper and/or contacting a greater volume of soil tend to have better performance than those which have shallow placement or are in contact with a smaller amount of soil. The below grade basement sub-slab coils and foundation spiral-coil loop consistently absorbed more energy during the heating season and rejected more heat during the cooling season compared to the garage and septic coils.

  2. Digital controller design: Analysis of the annular suspension pointing system

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The annular suspension and pointing system (ASPS) a payload auxiliary pointing device of the space shuttle is briefly described along with the function of the digital controller. The equations of motion of a simplified plan planar model of the ASPS are derived. Results of computer simulations are discussed.

  3. Clinical Application of Insertion Force Sensor System for Coil Embolization of Intracranial Aneurysms.

    PubMed

    Matsubara, Noriaki; Miyachi, Shigeru; Izumi, Takashi; Yamada, Hiroyuki; Marui, Naoki; Ota, Keisuke; Tajima, Hayato; Shintai, Kazunori; Ito, Masashi; Imai, Tasuku; Nishihori, Masahiro; Wakabayashi, Toshihiko

    2017-09-01

    In endovascular embolization for intracranial aneurysms, it is important to properly control the coil insertion force. However, the force can only be subjectively detected by the subtle feedback experienced by neurointerventionists at their fingertips. The authors envisioned a system that would objectively sense and quantify that force. In this article, coil insertion force was measured in cases of intracranial aneurysm using this sensor, and its actual clinical application was investigated. The sensor consists of a hemostatic valve (Y-connector). A little flexure was intentionally added in the device, and it creates a bend in the delivery wire. The sensor measures the change in the position of the bent wire depending on the insertion force and translates it into a force value. Using this, embolization was performed for 10 unruptured intracranial aneurysms. The sensor adequately recorded the force, and it reflected the operators' usual clinical experience. The presence of the sensor did not affect the procedures. The sensor enabled the operators to objectively note and evaluate the insertion force and better cooperative handling was possible. Additionally, other members of the intervention team shared the information. Force records demonstrated the characteristic patterns according to every stage of coiling (framing, filling, and finishing). The force sensor system adequately measured coil insertion force in intracranial aneurysm coil embolization procedures. The safety of this sensor was demonstrated in clinical application for the limited number of patients. This system is useful adjunct for assisting during coil embolization for an intracranial aneurysm. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. System for maintaining sediment suspensions during larval fish studies

    USGS Publications Warehouse

    Chilton, E.W.

    1991-01-01

    A new system was developed for maintaining suspensions of inorganic solids during laboratory studies on early life stages of fish. Microfine bentonite was successfully held in suspension in specially constructed units during a 21-d fishless test, a 28-d experiment with juvenile green sunfish (lepomis cyanellus), and four shorter experiments (5-9 d) with four species of larval fishes, white sucker (catostomus commersoni), northern pike (esox lucius), channel catfish (ictalurus punctatus), and walleye (stizostedion vitreum). Each experiment on larval fish was conducted until the yolk-sac had been absorbed. Concentrations of bentonite ranged from 0 to 728 mg/l. Each unit consisted of a holding chamber set in a stainless steel bowl and two submersible pumps that recirculated the suspension. Turbidity readings remained nearly constant throughout each experiment. Because the turbidity of suspensions was well correlated with bentonite concentration (r2 = 0.989) And easy to measure, turbidity was used as an indicator of concentration. The system is inexpensive, easy to assemble, and does not require a diluter system to maintain constant concentrations of suspended material.

  5. Design of a Superconducting Magnetic Suspension System for a Liquid Helium Flow Experiment

    NASA Technical Reports Server (NTRS)

    Smith, Michael R.; Eyssa, Yehia M.; VanSciver, Steven W.

    1996-01-01

    We discuss a preliminary design for a superconducting magnetic suspension system for measurement of drag on rotationally symmetric bodies in liquid helium. Superconducting materials are a natural choice for liquid helium studies, since temperatures are well below most critical temperatures, so that the resulting heat load is negligible. Also, due to its diamagnetic properties, a superconducting model (for example made or coated with Nb) is inherently stable against disturbances. Issues which we consider include model placement during initial cool-down, maintaining placement during anticipated drag and lift forces, and force measurement. This later can be achieved by a passive technique, where the body is allowed to deflect under the influence of drag from its neutral position. The resulting shift in flux is detected via a superconducting pickup coil. The pickup coil may be connected either to a SQUID, or a secondary loop wound around a Hall probe. Both options are discussed. The objective of this work is to gain a better understanding of the nature of turbulent fields in normal and superfluid helium for potential application to problems in classical high Reynolds number turbulence.

  6. Static Measurements on HTS Coils of Fully Superconducting AC Electric Machines for Aircraft Electric Propulsion System

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin B.; Hunker, Keith R.; Hartwig, Jason; Brown, Gerald V.

    2017-01-01

    The NASA Glenn Research Center (GRC) has been developing the high efficiency and high-power density superconducting (SC) electric machines in full support of electrified aircraft propulsion (EAP) systems for a future electric aircraft. A SC coil test rig has been designed and built to perform static and AC measurements on BSCCO, (RE)BCO, and YBCO high temperature superconducting (HTS) wire and coils at liquid nitrogen (LN2) temperature. In this paper, DC measurements on five SC coil configurations of various geometry in zero external magnetic field are measured to develop good measurement technique and to determine the critical current (Ic) and the sharpness (n value) of the super-to-normal transition. Also, standard procedures for coil design, fabrication, coil mounting, micro-volt measurement, cryogenic testing, current control, and data acquisition technique were established. Experimentally measured critical currents are compared with theoretical predicted values based on an electric-field criterion (Ec). Data here are essential to quantify the SC electric machine operation limits where the SC begins to exhibit non-zero resistance. All test data will be utilized to assess the feasibility of using HTS coils for the fully superconducting AC electric machine development for an aircraft electric propulsion system.

  7. A hybrid electromagnetic shock absorber for active vehicle suspension systems

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Babak; Bolandhemmat, Hamidreza; Behrad Khamesee, Mir; Golnaraghi, Farid

    2011-02-01

    The use of electromagnetic dampers (ED) in vehicle active suspension systems has drawn considerable attention in the past few years, attributed to the fact that active suspension systems have shown superior performance in improving ride comfort and road handling of terrain vehicles, compared with their passive and semi-active counterparts. Although demonstrating superb performance, active suspensions still have some shortcomings that must be overcome. They have high energy consumption, weight, and cost and are not fail-safe in case of a power breakdown. The novel hybrid ED, which is proposed in this paper, is a potential solution to the above-mentioned drawbacks of conventional active suspension systems. The proposed hybrid ED is designed to inherit the high-performance characteristics of an active ED with the reliability of a passive damper in a single package. The eddy current damping effect is utilised as a source of the passive damping. First, a prototype ED is designed and fabricated. The prototype ED is then utilised to experimentally establish the design requirements for a real-size active ED. This is accomplished by comparing its vibration isolation performance in a 1-DOF quarter-car test rig with that of a same-class semi-active damper. Then, after a real-size active ED is designed, the concept of hybrid damper is introduced to the damper design to address the drawbacks of the active ED. Finally, the finite-element method is used to accurately model and analyse the designed hybrid damper. It is demonstrated that by introducing the eddy current damping effect to the active part, a passive damping of approximately 1570 Ns/m is achieved. This amount of passive damping guarantees that the damper is fail-safe and reduces the power consumption more than 70%, compared with an active ED in an automotive active suspension system.

  8. Design of Range Adaptive Wireless Power Transfer System Using Non-coaxial Coils

    NASA Astrophysics Data System (ADS)

    Yang, Dongsheng; Won, Sokhui; Hong, Huan

    2017-05-01

    Wireless Power Transfer (WPT) is a remarkable technology because of its convenience and applicability in harsh environment. Particularly, Magnetic Coupling WPT (MC-WPT) is a proper method to midrange power transfer, but the frequency splitting at over-coupling range, which is related with transfer distance, is challenge of transmission efficiency. In order to overcome this phenomenon, recently the range adaptive WPT is proposed. In this paper, we aim to the type with a set of non-coaxial driving coils, so that this may remove the connection wires from PA (Power Amplifier) to driving coil. And, when the radius of driving coil is changed, on the different gaps between driving and TX coils, coupling coefficient between these is computed in both cases of coaxial and non-coaxial configurations. In addition, the designing steps for 4-coil WPT system using non-coaxial coils are described with the example. Finally, the reliability of this topology has been proved and simulated with PSPICE.

  9. Impact of the Digital Coil Protection System and Plasma Shutdown Handler on NSTX-U Operations

    NASA Astrophysics Data System (ADS)

    Gerhardt, Stefan; Battaglia, D.; Boyer, M.; Erickson, K.; Mueller, D.; Myers, C.; Mueller, D.; Sabbagh, S. A.

    2016-10-01

    In order to prevent excessive forces on the NSTX-U vessel and coils, a digital coil protection system (DCPS) has been implemented. This system computes approximately 400 different forces/torques/stresses, and terminates the discharge if limits on those quantities are exceeded. It is desirable, however, to prevent these coil system trips from ever happening. Given that many of these limits would be reached during transients associated with disruptions, as ``discharge shutdown handler'' was coded in the plasma control system to automatically control the plasma shutdown. This is a state machine with five states, and a set of rules for transitioning between states. The first use of these systems during plasma operations on NSTX-U will be described, with a focus on operational experiences and directions for future improvements. Work Supported by U.S.D.O.E. Contract No. DE-AC02-09CH11466.

  10. Annular suspension and pointing system with controlled DC electromagnets

    NASA Technical Reports Server (NTRS)

    Vu, Josephine Lynn; Tam, Kwok Hung

    1993-01-01

    The Annular Suspension and Pointing System (ASPS) developed by the Flight System division of Sperry Corporation is a six-degree of freedom payload pointing system designed for use with the space shuttle. This magnetic suspension and pointing system provides precise controlled pointing in six-degrees of freedom, isolation of payload-carrier disturbances, and end mount controlled pointing. Those are great advantages over the traditional mechanical joints for space applications. In this design, we first analyzed the assumed model of the single degree ASPS bearing actuator and obtained the plant dynamics equations. By linearizing the plant dynamics equations, we designed the cascade and feedback compensators such that a stable and satisfied result was obtained. The specified feedback compensator was computer simulated with the nonlinearized plant dynamics equations. The results indicated that an unstable output occurred. In other words, the designed feedback compensator failed. The failure of the design is due to the Taylor's series expansion not converging.

  11. Guidance and Actuation Systems for an Adaptive-Suspension Vehicle

    DTIC Science & Technology

    1984-03-14

    FORM 1. REPORT NUMBER 2. GOVT ACCESSION NO. 3 . RECIPIENT’S CATALOG NUMBER G8186-685-84 ’D Ji 4. TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED...Adaptive-Suspension Vehicle ..... ........ 2 2.2.2 The Terrain-Sensing System ...... .......... 3 2.3 Guidance System Algorithms... 3 2.3.1 Overview ............. ................... 3 2.3.2 Elevation Map Algorithms ...... ........... 3 2.3.3 Vehicle Guidance Algorithms

  12. A superconducting large-angle magnetic suspension

    NASA Technical Reports Server (NTRS)

    Downer, James R.; Anastas, George V., Jr.; Bushko, Dariusz A.; Flynn, Frederick J.; Goldie, James H.; Gondhalekar, Vijay; Hawkey, Timothy J.; Hockney, Richard L.; Torti, Richard P.

    1992-01-01

    SatCon Technology Corporation has completed a Small Business Innovation Research (SBIR) Phase 2 program to develop a Superconducting Large-Angle Magnetic Suspension (LAMS) for the NASA Langley Research Center. The Superconducting LAMS was a hardware demonstration of the control technology required to develop an advanced momentum exchange effector. The Phase 2 research was directed toward the demonstration for the key technology required for the advanced concept CMG, the controller. The Phase 2 hardware consists of a superconducting solenoid ('source coils') suspended within an array of nonsuperconducting coils ('control coils'), a five-degree-of-freedom positioning sensing system, switching power amplifiers, and a digital control system. The results demonstrated the feasibility of suspending the source coil. Gimballing (pointing the axis of the source coil) was demonstrated over a limited range. With further development of the rotation sensing system, enhanced angular freedom should be possible.

  13. A novel functional magnetic resonance imaging compatible search-coil eye-tracking system.

    PubMed

    Oeltermann, Axel; Ku, Shih-Pi; Logothetis, Nikos K

    2007-07-01

    Measuring eye movements (EMs) using the search-coil eye-tracking technique is superior to video-based infrared methods [Collewijn H, van der Mark F, Jansen TC. Precise recording of human eye movements. Vision Res 1975;15(3):447-50], which suffer from the instability of pupil size, blinking behavior and lower temporal resolution. However, no conventional functional magnetic resonance imaging (fMRI)-compatible search-coil eye tracker exists. The main problems for such a technique are the interaction between the transmitter coils and the magnetic gradients used for imaging as well as the limited amount of space in a scanner. Here we present an approach to overcome these problems and we demonstrate a method to record EMs in an MRI scanner using a search coil. The system described has a spatial resolution of 0.07 degrees (visual angle) and a high temporal resolution (22 kHz). The transmitter coils are integrated into the visual presentation system and the control/analysis unit is portable, which enables us to integrate the eye tracker with an MRI scanner. Our tests demonstrate low noise in the recorded eye traces and scanning with minimal artifact. Furthermore, the induced current in the search coil caused by the RF pulses does not lead to measurable heating. Altogether, this MR-compatible search-coil eye tracker can be used to precisely monitor EMs with high spatial and temporal resolution during fMRI. It can therefore be of great importance for studies requiring accurate fixation of a target, or measurement and study of the subject's oculomotor system.

  14. Condition Monitoring System Designing of GIS Based on Trip/close Coil Current

    NASA Astrophysics Data System (ADS)

    Wei, Dongliang; Wang, Zhi; Xue, Feng; Li, Haitao

    2017-05-01

    In this article, the types and characteristics of the faults from GIS were analyzed that the major failures were caused by its operating mechanism and auxiliary control circuits. While a useful parameter to effectively diagnose the mechanical failures of GIS is the trip/close coil current which is accessible and easy-to-measure. A portable system has been design to monitor the condition of GIS by detecting the coil current. This system was fulfilled with functions like signal sampling, processing, transmitting and performing. DSP and ARM11 carrying WINCE 6.0 have been used to construct the system. The feasibility and reliability were validated through several repeated experiments.

  15. Design and analysis of an intelligent controller for active geometry suspension systems

    NASA Astrophysics Data System (ADS)

    Goodarzi, Avesta; Oloomi, Ehsan; Esmailzadeh, Ebrahim

    2011-02-01

    An active geometry suspension (AGS) system is a device to optimise suspension-related factors such as toe angle and roll centre height by controlling vehicle's suspension geometry. The suspension geometry could be changed through control of suspension mounting point's position. In this paper, analysis and control of an AGS system is addressed. First, the effects of suspension geometry change on roll centre height and toe angle are studied. Then, based on an analytical approach, the improvement of the vehicle's stability and handling due to the control of suspension geometry is investigated. In the next section, an eight-degree-of-freedom handling model of a sport utility vehicle equipped with an AGS system is introduced. Finally, a self-tuning proportional-integral controller has been designed, using the fuzzy control theory, to control the actuator that changes the geometry of the suspension system. The simulation results show that an AGS system can improve the handling and stability of the vehicle.

  16. An efficient calibration method for SQUID measurement system using three orthogonal Helmholtz coils

    NASA Astrophysics Data System (ADS)

    Hua, Li; Shu-Lin, Zhang; Chao-Xiang, Zhang; Xiang-Yan, Kong; Xiao-Ming, Xie

    2016-06-01

    For a practical superconducting quantum interference device (SQUID) based measurement system, the Tesla/volt coefficient must be accurately calibrated. In this paper, we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils. The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil. By applying magnetic fields through a three-dimensional Helmholtz coil, the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields. Calibration with alternating current (AC) field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current (DC) calibration to avoid possible effects due to eddy current. In our experiment, a calibration relative error of about 6.89 × 10-4 is obtained, and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils. The method does not need precise alignment of the magnetometer inside the Helmholtz coil. It can be used for the multichannel magnetometer system calibration effectively and accurately. Project supported by the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB04020200) and the Shanghai Municipal Science and Technology Commission Project, China (Grant No. 15DZ1940902).

  17. Dynamically stable magnetic suspension/bearing system

    DOEpatents

    Post, R.F.

    1996-02-27

    A magnetic bearing system contains magnetic subsystems which act together to support a rotating element in a state of dynamic equilibrium. However, owing to the limitations imposed by Earnshaw`s Theorem, the magnetic bearing systems to be described do not possess a stable equilibrium at zero rotational speed. Therefore, mechanical stabilizers are provided, in each case, to hold the suspended system in equilibrium until its speed has exceeded a low critical speed where dynamic effects take over, permitting the achievement of a stable equilibrium for the rotating object. A state of stable equilibrium is achieved above a critical speed by use of a collection of passive elements using permanent magnets to provide their magnetomotive excitation. The magnetic forces exerted by these elements, when taken together, levitate the rotating object in equilibrium against external forces, such as the force of gravity or forces arising from accelerations. At the same time, this equilibrium is made stable against displacements of the rotating object from its equilibrium position by using combinations of elements that possess force derivatives of such magnitudes and signs that they can satisfy the conditions required for a rotating body to be stably supported by a magnetic bearing system over a finite range of those displacements. 32 figs.

  18. Dynamically stable magnetic suspension/bearing system

    DOEpatents

    Post, Richard F.

    1996-01-01

    A magnetic bearing system contains magnetic subsystems which act together to support a rotating element in a state of dynamic equilibrium. However, owing to the limitations imposed by Earnshaw's Theorem, the magnetic bearing systems to be described do not possess a stable equilibrium at zero rotational speed. Therefore, mechanical stabilizers are provided, in each case, to hold the suspended system in equilibrium until its speed has exceeded a low critical speed where dynamic effects take over, permitting the achievement of a stable equilibrium for the rotating object. A state of stable equilibrium is achieved above a critical speed by use of a collection of passive elements using permanent magnets to provide their magnetomotive excitation. The magnetic forces exerted by these elements, when taken together, levitate the rotating object in equilibrium against external forces, such as the force of gravity or forces arising from accelerations. At the same time, this equilibrium is made stable against displacements of the rotating object from its equilibrium position by using combinations of elements that possess force derivatives of such magnitudes and signs that they can satisfy the conditions required for a rotating body to be stably supported by a magnetic bearing system over a finite range of those displacements.

  19. Modeling and control of the magnetic suspension system.

    PubMed

    Golob, Marjan; Tovornik, Boris

    2003-01-01

    A fuzzy logic based controller applied to a simple magnetic suspension is presented in this paper. The simple electromagnet-ball system and the contactless optical position measurement system are developed as a physical model of the magnetic suspension. A nonlinear mathematical model is presented and linearized. This model has been used to design a discrete linear PID controller with optimal parameters. The physical real-time model was constructed in order to compare the performance of the linear discrete PID controller and the proposed fuzzy logic based PID controller. The decomposed fuzzy PID controller has proportional, integral, and derivative separate parts which are tuned independently. When testing it becomes clear that the decomposed fuzzy PID controller gives better performance over a typical operational range than a traditional linear PID controller.

  20. Experimental studies on semi active suspension systems with various dampers

    NASA Astrophysics Data System (ADS)

    Kumar, B. Anil; Bharath Raj, Ch; Rajendar, K.

    2015-12-01

    Some results of an experimental probe on semi Active suspension systems with various Dampers have been studied in the present paper. Dampers with different configurations were studied by using Magneto Rheological gel Damper. A comparison have been done for different configurations of Dampers viz.MR gel Damper with Magnetic field, MR gel Damper without magnetic field, Damper with conventional oil, Natural vibration without damper.

  1. The 13-inch magnetic suspension and balance system wind tunnel

    NASA Technical Reports Server (NTRS)

    Johnson, William G., Jr.; Dress, David A.

    1989-01-01

    NASA Langley has a small, subsonic wind tunnel in use with the 13-inch Magnetic Suspension and Balance System (MSBS). The tunnel is capable of speeds up to Mach 0.5. This report presents tunnel design and construction details. It includes flow uniformity, angularity, and velocity fluctuation data. It also compares experimental Mach number distribution data with computed results for the General Electric Streamtube Curvature Program.

  2. 5 CFR 919.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... debarment and suspension system? 919.110 Section 919.110 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General § 919.110 What is the purpose of the nonprocurement debarment and suspension system?...

  3. Force Measurements in Magnetic Suspension and Balance System

    NASA Technical Reports Server (NTRS)

    Kuzin, Alexander; Shapovalov, George; Prohorov, Nikolay

    1996-01-01

    The description of an infrared telemetry system for measurement of drag forces in Magnetic Suspension and Balance Systems (MSBS) is presented. This system includes a drag force sensor, electronic pack and transmitter placed in the model which is of special construction, and receiver with a microprocessor-based measuring device, placed outside of the test section. Piezosensitive resonators as sensitive elements and non-magnetic steel as the material for the force sensor are used. The main features of the proposed system for load measurements are discussed and the main characteristics are presented.

  4. On the analysis of using 3-coil wireless power transfer system in retinal prosthesis.

    PubMed

    Bai, Shun; Skafidas, Stan

    2014-01-01

    Designing a wireless power transmission system(WPTS) using inductive coupling has been investigated extensively in the last decade. Depending on the different configurations of the coupling system, there have been various designing methods to optimise the power transmission efficiency based on the tuning circuitry, quality factor optimisation and geometrical configuration. Recently, a 3-coil WPTS was introduced in retinal prosthesis to overcome the low power transferring efficiency due to low coupling coefficient. Here we present a method to analyse this 3-coil WPTS using the S-parameters to directly obtain maximum achievable power transferring efficiency. Through electromagnetic simulation, we brought a question on the condition of improvement using 3-coil WPTS in powering retinal prosthesis.

  5. A magnetic suspension system with a large angular range

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.; Ghofrani, Mehran

    1993-01-01

    The paper describes a small-scale laboratory system, called the Large-Angle Magnetic Suspension Test Fixture (LAMSTF), constructed at NASA Langley Research Center in order to explore and develop technology required for the magnetic suspension of objects over large ranges of orientation. The LAMSTF hardware comprises five electromagnets in a circular arrangement, each driven from a separate bipolar power amplifier. The suspended element is a cylindrical axially magnetized permanent magnet core, within an aluminum tube. The element, which is 'levitated' by repulsive forces, is stabilized in five degrees-of-freedom, with rotation about the cylinder axis not controlled. The controller accommodates the changes in magnetic coupling between the electromagnets and the suspended element by real-time adaptation of a decoupling matrix. The paper presents performance measurements demonstrating that the major design objective of the 360 deg rotation was accomplished.

  6. High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range

    SciTech Connect

    Lin, Tingting; Zhao, Jing; Zhang, Yi; Krause, Hans-Joachim; Lee, Yong-Ho; Lin, Jun

    2014-11-15

    In several low-field Nuclear Magnetic Resonance (LF-NMR) and surface nuclear magnetic resonance applications, i.e., in the frequency range of kHz, high sensitivity magnetic field detectors are needed. Usually, low-T{sub c} superconducting quantum interference devices (SQUIDs) with a high field sensitivity of about 1 fT/Hz{sup 1/2} are employed as detectors. Considering the flux trapping and operational difficulties associated with low-T{sub c} SQUIDs, we designed and fabricated liquid-nitrogen-cooled Cu coils for NMR detection in the kHz range. A cooled coil system consisting of a 9-cm diameter Cu coil and a low noise preamplifier was systematically investigated and reached a sensitivity of 2 fT/Hz{sup 1/2} at 77 K, which is 3 times better compared to the sensitivity at 300 K. A Q-switch circuit as an essential element for damping the ringing effects of the pickup coil was developed to acquire free induction decay signals of a water sample with minimum loss of signal. Our studies demonstrate that cooled Cu coils, if designed properly, can provide a comparable sensitivity to low-T{sub c} SQUIDs.

  7. The superconducting coil system of the advanced modular stellarator Wendelstein 7-X

    SciTech Connect

    Maurer, W.

    1994-11-01

    Wendelstein 7-X (W 7-X) is the largest stellarator experiment envisaged worldwide. It is prepared in the Max-Planck-Institute for Plasma Physics in Garching near Munich, Germany. The main goal of the experiment is demonstration of the optimized stellarator concept as an appropriate route for a fusion reactor. Essential physics and technical goals of this experiment are: demonstration of stationary operation, achievement of plasma parameters which allow a reliable prediction of the properties of a future stellarator reactor plasma without striving for ignition, and generation of the magnetic confinement with superconducting modular coils in a stellarator for the first time. The optimization criteria of the coil system are described and the status of the engineering development programme for the coils which is a common task of IPP and the nuclear research center KfK in Karlsruhe are reported.

  8. Wireless powering of single-chip systems with integrated coil and external wire-loop resonator

    NASA Astrophysics Data System (ADS)

    Segura-Quijano, Fredy; García-Cantón, Jesús; Sacristán, Jordi; Osés, Teresa; Baldi, Antonio

    2008-02-01

    A procedure for inductive wireless powering of single-chip systems is presented. An integrated spiral coil is used as the power receiving component. An external resonator formed by a wire-loop inductor connected to a capacitor is placed in close proximity to the chip. The sinusoidal magnetic field generated at a distant transmitting loop is amplified by the resonator. The present approach enables delivering power in the order of tens of microwatts to a few milliwatts at distances longer than 10cm using a frequency of 13.5MHz. The integrated coil used here can be fabricated with any integrated circuit fabrication technology.

  9. Annular Suspension and Pointing System (ASPS) magnetic rotary joint

    NASA Technical Reports Server (NTRS)

    Smith, W. E.; Quach, W.; Thomas, W.

    1993-01-01

    The Annular Suspension and Pointing System (ASPS) is a prototype of flight hardware for a high-accuracy space payload pointing mount. The long term project objective is to perform modifications and implement improvements to the existing ASPS in hopes of recommission. Also, new applications will be investigated for this technology. This report will focus on the first aspect of this overall goal, to establish operation of a single bearing station. Presented is an overview of the system history and bearing operation followed by the processes, results, and status of the single bearing study.

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

    NASA Technical Reports Server (NTRS)

    Provenza, Andy J.

    2000-01-01

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

  11. A magnetic induction heating system with multi-cascaded coils and adjustable magnetic circuit for hyperthermia.

    PubMed

    Huang, Chi-Fang; Chao, Hsuan-Yi; Chang, Hsun-Hao; Lin, Xi-Zhang

    2016-01-01

    Based on the characteristics of cancer cells that cannot survive in an environment with temperature over 42 °C, a magnetic induction heating system for cancer treatment is developed in this work. First, the methods and analyses for designing the multi-cascaded coils magnetic induction hyperthermia system are proposed, such as internal impedance measurement of power generator, impedance matching of coils, and analysis of the system. Besides, characteristics of the system are simulated by a full-wave package for engineering optimization. Furthermore, by considering the safety factor of patients, a two-sectional needle is designed for hyperthermia. Finally, this system is employed to test the liver of swine in ex-vivo experiments, and through Hematoxylin and Eosin (H&E) stain and NADPH oxidase activity assay, the feasibility of this system is verified.

  12. Smart suspension systems for bridge-friendly vehicles

    NASA Astrophysics Data System (ADS)

    Chen, Yonghong; Tan, Chin An; Bergman, Larry A.; Tsao, T. C.

    2002-06-01

    In this paper, the effects of using semi-active control strategy (such as MR dampers) in vehicle suspensions on the coupled vibrations of a vehicle traversing a bridge are examined in order to develop various designs of smart suspension systems for bridge-friendly vehicles. The bridge-vehicle coupled system is modeled as a simply supported beam traversed by a two-degree-of-freedom quarter-car model. The surface unevenness on the bridge deck is modeled as a deterministic profile of a sinusoidal wave. As the vehicle travels along the bridge, the system is excited as a result of the surface unevenness and this excitation is characterized by a frequency defined by the speed of travel and the wavelength of the profile. The dynamic interactions between the bridge and the vehicle due to surface deck irregularities are obtained by solving the coupled equations of motion. Numerical results of a passive control strategy show that, when the lower natural frequency of the vehicle matches with a natural frequency (usually the first frequency) of the bridge and the excitation frequency, the maximum response of the bridge is large while the response of the vehicle is relatively smaller, meaning that the bridge behaves like a vibration absorber. This is undesirable from a bridge design viewpoint. Comparative studies of passive and semi-active controls for the vehicle suspension are performed. It is demonstrated that skyhook control can significantly mitigate the response of the bridge, while ground-hook control reduces the tire force impacted onto the bridge.

  13. An Actively Decoupled Dual Transceiver Coil System for Continuous ASL at 7 T

    PubMed Central

    Stafford, Randall B.; Woo, Myung-Kyun; Oh, Se-Hong; Dolui, Sudipto; Zhao, Tiejun; Kim, Young-Bo; Detre, John A.; Cho, Zang-Hee; Lee, Jongho

    2016-01-01

    7 T arterial spin labeling (ASL) faces major challenges including the increased specific absorption rate (SAR) and increased B0 and B1 inhomogeneity. This work describes the design and implementation of a dual-coil system that allows for continuous ASL (CASL) at 7 T. This system consisted of an actively detunable eight-channel transceiver head coil, and a three-channel transceiver labeling coil. Four experiments were performed in 5 healthy subjects: (i) to demonstrate that active detuning during ASL labeling reduces magnetization transfer; (ii) to measure the B1 profile at the labeling plane; (iii) to quantify B0 off-resonance at the labeling plane; and (iv) to collect in vivo CASL data. The magnetization transfer ratio in the head coil was reduced to 0.0 ± 0.2% by active detuning during labeling. The measured B1 profiles in all 5 subjects were sufficient to satisfy the flow-driven adiabatic inversion necessary for CASL, however the actual labeling efficiency was significantly impacted by B0 off-resonance at the labeling plane. The measured CASL percent signal change in gray matter (0.94% ± 0.10%) corresponds with the low labeling efficiency predicted by the B0 off-resonance. This work demonstrates progress in the technical implementation of 7 T CASL, and reinforces the need for improved B0 homogeneity at the labeling plane. PMID:27695192

  14. Magnetic Suspension and Balance Systems: A Selected, Annotated Bibliography

    NASA Technical Reports Server (NTRS)

    Tuttle Marie H.; Kilgore, Robert A.; Boyden, Richmond P.

    1983-01-01

    This publication, containing 206 entries, supersedes an earlier bibliography, NASA TM-80225 (April 1980). Citations for 18 documents have been added in this updated version. Most of the additions report results of recent studies aimed at increasing the research capabilities of magnetic suspension and balance systems, e.g., increasing force and torque capability, increasing angle of attack capability, and increasing overall system reliability. Some of the additions address the problem of scaling from the relatively small size of existing systems to much larger sizes. The purpose of this bibliography is to provide an up-to-date list of publications that might be helpful to persons interested in magnetic suspension and balance systems for use in wind tunnels. The arrangement is generally chronological by date of publication. However, papers presented at conferences or meetings are placed under dates of presentation. The numbers assigned to many of the citations have been changed from those used in the previous bibliography. This has been done in order to allow outdated citations to be removed and some recently discovered older works to be included in their proper chronological order.

  15. Molecular basis of coiled-coil oligomerization-state specificity.

    PubMed

    Ciani, Barbara; Bjelic, Saša; Honnappa, Srinivas; Jawhari, Hatim; Jaussi, Rolf; Payapilly, Aishwarya; Jowitt, Thomas; Steinmetz, Michel O; Kammerer, Richard A

    2010-11-16

    Coiled coils are extensively and successfully used nowadays to rationally design multistranded structures for applications, including basic research, biotechnology, nanotechnology, materials science, and medicine. The wide range of applications as well as the important functions these structures play in almost all biological processes highlight the need for a detailed understanding of the factors that control coiled-coil folding and oligomerization. Here, we address the important and unresolved question why the presence of particular oligomerization-state determinants within a coiled coil does frequently not correlate with its topology. We found an unexpected, general link between coiled-coil oligomerization-state specificity and trigger sequences, elements that are indispensable for coiled-coil formation. By using the archetype coiled-coil domain of the yeast transcriptional activator GCN4 as a model system, we show that well-established trimer-specific oligomerization-state determinants switch the peptide's topology from a dimer to a trimer only when inserted into the trigger sequence. We successfully confirmed our results in two other, unrelated coiled-coil dimers, ATF1 and cortexillin-1. We furthermore show that multiple topology determinants can coexist in the same trigger sequence, revealing a delicate balance of the resulting oligomerization state by position-dependent forces. Our experimental results should significantly improve the prediction of the oligomerization state of coiled coils. They therefore should have major implications for the rational design of coiled coils and consequently many applications using these popular oligomerization domains.

  16. Low cost optical tweezers systems using double coil driving stepping motor to controlling sample stage

    NASA Astrophysics Data System (ADS)

    Laowattanatham, N.; Cheamanunkul, N.; Plaipichit, S.; Buranasiri, P.; Nuansri, R.

    2013-06-01

    In this research, the low cost optical tweezers systems using X-Y stage has been developed by using 5-phase stepping motor. By using sequential double coil driving, we can obtain the driving torque larger than using the single coil driving. The moving scale is fine resolution at 0.2 micrometer. The overall systems based on microcontroller PIC18F458 and joystick controller with LabView® graphical user interface (GUI). The mechanical damping has been included in the system for decreasing the vibrational noise. By using this method, our optical tweezers system is cheaper than the other commercial system that has been used the piezoelectric driving, and still has the same efficiency.

  17. Plate coil thermal test bench for the Daniel K. Inouye Solar Telescope (DKIST) carousel cooling system

    NASA Astrophysics Data System (ADS)

    Phelps, LeEllen; Murga, Gaizka; Montijo, Guillermo; Hauth, David

    2014-08-01

    Analyses have shown that even a white-painted enclosure requires active exterior skin-cooling systems to mitigate dome seeing which is driven by thermal nonuniformities that change the refractive index of the air. For the Daniel K. Inouye Solar Telescope (DKIST) Enclosure, this active surface temperature control will take the form of a system of water cooled plate coils integrated into the enclosure cladding system. The main objective of this system is to maintain the surface temperature of the enclosure as close as possible to, but always below, local ambient temperature in order to mitigate this effect. The results of analyses using a multi-layer cladding temperature model were applied to predict the behavior of the plate coil cladding system and ultimately, with safety margins incorporated into the resulting design thermal loads, the detailed designs. Construction drawings and specifications have been produced. Based on these designs and prior to procurement of the system components, a test system was constructed in order to measure actual system behavior. The data collected during seasonal test runs at the DKIST construction site on Haleakalā are used to validate and/or refine the design models and construction documents as appropriate. The test fixture was also used to compare competing hardware, software, components, control strategies, and configurations. This paper outlines the design, construction, test protocols, and results obtained of the plate coil thermal test bench for the DKIST carousel cooling system.

  18. Dynamic stability of repulsive-force maglev suspension systems

    SciTech Connect

    Cai, Y.; Rote, D.M.; Mulcahy, T.M.; Wang, Z.

    1996-11-01

    This report summarizes the research performed on maglev vehicle dynamic stability at Argonne National Laboratory during the past few years. It also documents both measured and calculated magnetic-force data. Because dynamic instability is not acceptable for any commercial maglev system, it is important to consider this phenomenon in the development of all maglev systems. This report presents dynamic stability experiments on maglev systems and compares the results with predictions calculated by a nonlinear-dynamics computer code. Instabilities of an electrodynamic-suspension system type vehicle model were obtained by experimental observation and computer simulation of a five-degree-of-freedom maglev vehicle moving on a guideway that consists of a pair of L-shaped aluminum conductors attached to a rotating wheel. The experimental and theoretical analyses developed in this study identify basic stability characteristics and future research needs of maglev systems.

  19. Fault detection in electromagnetic suspension systems with state estimation methods

    SciTech Connect

    Sinha, P.K.; Zhou, F.B.; Kutiyal, R.S. . Dept. of Engineering)

    1993-11-01

    High-speed maglev vehicles need a high level of safety that depends on the whole vehicle system's reliability. There are many ways of attaining high reliability for the system. Conventional method uses redundant hardware with majority vote logic circuits. Hardware redundancy costs more, weigh more and occupy more space than that of analytically redundant methods. Analytically redundant systems use parameter identification and state estimation methods based on the system models to detect and isolate the fault of instruments (sensors), actuator and components. In this paper the authors use the Luenberger observer to estimate three state variables of the electromagnetic suspension system: position (airgap), vehicle velocity, and vertical acceleration. These estimates are compared with the corresponding sensor outputs for fault detection. In this paper, they consider FDI of the accelerometer, the sensor which provides the ride quality.

  20. Research on automatic non-destructive testing system of oil coiled tubing

    NASA Astrophysics Data System (ADS)

    Guo, Rong; Qiu, Wenbin; Wang, Yuhui; Ren, Jianguang

    2010-10-01

    A method using ultrasonic devices for on-line measurement of oil coiled tubing was proposed. The principle of ultrasonic testing was analyzed. Then, the structure of the system consisting of mechanical system, coupling system, measuring system, control system and system software was determinated. Based on the analysis of technology requirement, measuring technique in which the coiled tubing did not rotate and the probe was static was chosen. The ultrasonic testing probes were triggered in turn. After signal sampling, digital filtering and A / D conversion signal processing, the received echo signals were sent to computer. Through analyzing and accounting, the test results were obtained. Based on VC++.net, A-type ultrasonic and C-type ultrasonic display software and the inspection data processing software were developed. Using Windows programming technology, the software structure and function library were totally open. Therefore, secondary development can be carried out conveniently. Based on the experimental studies, coiled tubing's ultrasonic testing system is developed. The testing results show that the system has specific advantages such as high-adaptation, highefficiency, high- stability, high reliability and can meet the need of the users. The ultrasonic testing technologies proposed in this paper can be applied extensively to other tubes.

  1. DSP based lunar sampling control system for the coiling-type sampler

    NASA Astrophysics Data System (ADS)

    Ling, Yun; Song, Aiguo; Lu, Wei

    2011-12-01

    The paper develops a control system based on DSP28334 for lunar sampling, and provides the main structure of it. The critical hardware and software design of the system are introduced in detail. The emphasis is placed on the design and realization of the vibration control of the coiling-type sampler in the process of lunar sampling. A control strategy which combines manual-control and local autonomous control is applied for the lunar sampling control. And the sampling mechanism being controlled can realizes multi-motor units working at time-sharing, which reduces the power comsumption and increases the stability of the sampling system greatly. The practical application of the control strategy used for the coiling-type sampler is verified by the finite element analysis. The experiments results show that the system works with low power consumption and high efficiency, and the proposed strategy enables greater depth and better efficiency during sampling.

  2. Gait Biomechanics of Individuals with Transtibial Amputation: Effect of Suspension System

    PubMed Central

    Eshraghi, Arezoo; Abu Osman, Noor Azuan; Karimi, Mohammad; Gholizadeh, Hossein; Soodmand, Ehsan; Abas, Wan Abu Bakar Wan

    2014-01-01

    Prosthetic suspension system is an important component of lower limb prostheses. Suspension efficiency can be best evaluated during one of the vital activities of daily living, i.e. walking. A new magnetic prosthetic suspension system has been developed, but its effects on gait biomechanics have not been studied. This study aimed to explore the effect of suspension type on kinetic and kinematic gait parameters during level walking with the new suspension system as well as two other commonly used systems (the Seal-In and pin/lock). Thirteen persons with transtibial amputation participated in this study. A Vicon motion system (six cameras, two force platforms) was utilized to obtain gait kinetic and kinematic variables, as well as pistoning within the prosthetic socket. The gait deviation index was also calculated based on the kinematic data. The findings indicated significant difference in the pistoning values among the three suspension systems. The Seal-In system resulted in the least pistoning compared with the other two systems. Several kinetic and kinematic variables were also affected by the suspension type. The ground reaction force data showed that lower load was applied to the limb joints with the magnetic suspension system compared with the pin/lock suspension. The gait deviation index showed significant deviation from the normal with all the systems, but the systems did not differ significantly. Main significant effects of the suspension type were seen in the GRF (vertical and fore-aft), knee and ankle angles. The new magnetic suspension system showed comparable effects in the remaining kinetic and kinematic gait parameters to the other studied systems. This study may have implications on the selection of suspension systems for transtibial prostheses. Trial Registration Iranian Registry of Clinical Trials IRCT2013061813706N1. PMID:24865351

  3. Digital control analysis and design of a field-sensed magnetic suspension system.

    PubMed

    Li, Jen-Hsing; Chiou, Juing-Shian

    2015-03-13

    Magnetic suspension systems are mechatronic systems and crucial in several engineering applications, such as the levitation of high-speed trains, frictionless bearings, and wind tunnels. Magnetic suspension systems are nonlinear and unstable systems; therefore, they are suitable educational benchmarks for testing various modeling and control methods. This paper presents the digital modeling and control of magnetic suspension systems. First, the magnetic suspension system is stabilized using a digital proportional-derivative controller. Subsequently, the digital model is identified using recursive algorithms. Finally, a digital mixed linear quadratic regulator (LQR)/H∞ control is adopted to stabilize the magnetic suspension system robustly. Simulation examples and a real-world example are provided to demonstrate the practicality of the study results. In this study, a digital magnetic suspension system model was developed and reviewed. In addition, equivalent state and output feedback controls for magnetic suspension systems were developed. Using this method, the controller design for magnetic suspension systems was simplified, which is the novel contribution of this study. In addition, this paper proposes a complete digital controller design procedure for magnetic suspension systems.

  4. Digital Control Analysis and Design of a Field-Sensed Magnetic Suspension System

    PubMed Central

    Li, Jen-Hsing; Chiou, Juing-Shian

    2015-01-01

    Magnetic suspension systems are mechatronic systems and crucial in several engineering applications, such as the levitation of high-speed trains, frictionless bearings, and wind tunnels. Magnetic suspension systems are nonlinear and unstable systems; therefore, they are suitable educational benchmarks for testing various modeling and control methods. This paper presents the digital modeling and control of magnetic suspension systems. First, the magnetic suspension system is stabilized using a digital proportional-derivative controller. Subsequently, the digital model is identified using recursive algorithms. Finally, a digital mixed linear quadratic regulator (LQR)/H∞ control is adopted to stabilize the magnetic suspension system robustly. Simulation examples and a real-world example are provided to demonstrate the practicality of the study results. In this study, a digital magnetic suspension system model was developed and reviewed. In addition, equivalent state and output feedback controls for magnetic suspension systems were developed. Using this method, the controller design for magnetic suspension systems was simplified, which is the novel contribution of this study. In addition, this paper proposes a complete digital controller design procedure for magnetic suspension systems. PMID:25781508

  5. Variable-Tension-Cord Suspension/Vibration-Isolation System

    NASA Technical Reports Server (NTRS)

    Villemarette, Mark L.; Boston, Joshua; RInks, Judith; Felice, Pat; Stein, Tim; Payne, Patrick

    2006-01-01

    A system for mechanical suspension and vibration isolation of a machine or instrument is based on the use of Kevlar (or equivalent aromatic polyamide) cord held in variable tension between the machine or instrument and a surrounding frame. The basic concept of such a tensioned-cord suspension system (including one in which the cords are made of aromatic polyamide fibers) is not new by itself; what is new here is the additional provision for adjusting the tension during operation to optimize vibration- isolation properties. In the original application for which this system was conceived, the objective is to suspend a reciprocating cryocooler aboard a space shuttle and to prevent both (1) transmission of launch vibrations to the cryocooler and (2) transmission of vibrations from the cryocooler to samples in a chamber cooled by the cryocooler. The basic mechanical principle of this system can also be expected to be applicable to a variety of other systems in which there are requirements for cord suspension and vibration isolation. The reciprocating cryocooler of the original application is a generally axisymmetric object, and the surrounding frame is a generally axisymmetric object with windows (see figure). Two cords are threaded into a spoke-like pattern between attachment rings on the cryocooler, holes in the cage, and cord-tension- adjusting assemblies. Initially, the cord tensions are adjusted to at least the level necessary to suspend the cryocooler against gravitation. Accelerometers for measuring vibrations are mounted (1) on the cold tip of the cryocooler and (2) adjacent to the cage, on a structure that supports the cage. During operation, a technician observes the accelerometer outputs on an oscilloscope while manually adjusting the cord tensions in an effort to minimize the amount of vibration transmitted to and/or from the cryocooler. A contemplated future version of the system would include a microprocessor-based control subsystem that would include cord

  6. Modeling and Identification of a Large Gap Magnetic Suspension System

    NASA Technical Reports Server (NTRS)

    Cox, David E. (Editor); Groom, Nelson J. (Editor); Hsiao, Min-Hung; Huang, Jen-Kuang

    1996-01-01

    This paper presents the results of modeling and system identification efforts on the NASA Large-Angle Magnetic Suspension Test Fixture (LAMSTF). The LAMSTF consists of a cylindrical permanent magnet which is levitated above a planar array of five electromagnets mounted in a circular configuration. The analytical model is first developed and open-loop characteristics are described. The system is shown to be highly unstable and requires feedback control in order to apply system identification. Limitations on modeling accuracy due to the effect of eddy-currents on the system are discussed. An algorithm is derived to identify a state-space model for the system from input/output data acquired during closed-loop operation. The algorithm is tested on both the baseline system and a perturbed system which has an increased presence of eddy currents. It is found that for the baseline system the analytic model adequately captures the dynamics, although the identified model improves the simulation accuracy. For the system perturbed by additional unmodeled eddy-currents the analytic model is no longer adequate and a higher-order model, determined through system identification, is required to accurately predict the system's time response.

  7. A modified percutaneous outpatient bladder neck suspension system.

    PubMed

    Benderev, T V

    1994-12-01

    During the last 8 years the original percutaneous needle suspension of Pereyra has been enhanced with the goal to reestablish safely and simply support of the pubocervical fascia in a reproducible and secure manner. Refinements include changes in points of suture attachment, limitation of suture tension and devices to perform the procedure simply and anchor the suspending suture in bone. A path along 2 planes of landmarks is used to guide the needle in capturing a maximum amount of mobile pubocervical fascia with a minimum risk of injury to the bladder or ureter. In 3 years over 150 patients have undergone this procedure. Early problems included suture breakage and inaccurate anchor placement. There have been no cases of chronic urinary retention. During the last 2 years the procedure has been performed on an outpatient basis. When suprapubic infection has been suspected, symptoms and signs have resolved with antibiotics. No sutures have been removed and osteitis pubis has not been noted. Any improvement in long-term durability has not yet been determined due to the history of ongoing refinements and the need for subsequent long-term followup. The specifics of this suspension system are described.

  8. Gradiometer pick-up coil design for a low field SQUID-MRI system.

    PubMed

    Seton, H C; Hutchison, J M; Bussell, D M

    1999-05-01

    We describe the use of liquid helium-cooled (4.2 K) gradiometer coils and a DC superconducting quantum interference device (SQUID) preamplifier to improve the SNR of magnetic resonance imaging (MRI) at 0.01 T. Gradiometer windings are used both to reduce lossy interactions with the MRI system's room temperature magnet and gradient coils and also to reject interference from more distant sources, which reduces the need for RF shielding. We have tested both axial and planar (figure-of-eight) gradiometer configurations. The figure-of-eight gradiometer has a more rapid fall-off in sensitivity with increasing distance from its windings than the axial gradiometer, but this is compensated for by reduced lossy interactions and improved interference rejection. We have used the system to image the human arm.

  9. Comparison of the APS and UGIMAG Helmholtz coil systems

    SciTech Connect

    Carnegie, D.W.

    1994-05-09

    UGIMAG is manufacturing the NdFeB permanent magnet blocks to be used in undulator A now being assembled by STI Optronics. The authors would like to be able to compare measurements made at the plant with those made at ANL and potentially with those made at the STI facility. Since there are no permanent magnet standard samples, measurement systems are compared by trading sets of magnets set aside as standards. APS has ten NdFeB permanent magnet blocks supplied by Sumitomo that they use to make these comparisons. These magnet samples have been extensively measured on the APS system. The data include the three vector components of the total magnetic dipole moment of the blocks as well as the spherical coordinates of the vector.

  10. Digital controller design: Analysis of the annular suspension pointing system

    NASA Technical Reports Server (NTRS)

    Kuo, B. C.

    1979-01-01

    The Annular Suspension and Pointing System (ASPS) is a payload auxiliary pointing device of the Space Shuttle. The ASPS is comprised of two major subassemblies, a vernier and a coarse pointing subsystem. The experiment is attached to a mounting plate/rim combination which is suspended on magnetic bearing/actuators (MBA) strategically located about the rim. Fine pointing is achieved by gimballing the plate/rim within the MBA gaps. Control about the experiment line-of-sight is obtained through the use of a non-contacting rim drive and positioning torquer. All sensors used to close the servo loops on the vernier system are noncontacting elements. Therefore, the experiment is a free-flyer constrained only by the magnetic forces generated by the control loops.

  11. A nonlinear kinematic and dynamic modeling of Macpherson suspension systems with a magneto-rheological damper

    NASA Astrophysics Data System (ADS)

    Dutta, Saikat; Choi, Seung-Bok

    2016-03-01

    It is well known that Macpherson strut suspension systems are widely used in light and medium weight vehicles. The performance of these suspension systems can be enriched by incorporating magneto-rheological (MR) dampers and an appropriate dynamic model is required in order to find out the ride comfort and other performances properly in the sense of practical environment conditions. Therefore, in this work the kinematic and dynamic modeling of Macpherson strut suspension system with MR damper is presented and its responses are evaluated. The governing equations are formulated using the kinematic properties of the suspension system and adopting Lagrange’s equation. In the formulation of the model, both the rotation of the wheel assembly and the lateral stiffness of the tire are considered to represent the nonlinear characteristic of Macpherson type suspension system. The formulated mathematical model is then compared with equivalent conventional quarter car suspension model and the different dynamic responses such as the displacement of the sprung mass are compared to emphasize the effectiveness of the proposed model. Additionally, in this work the important kinematic properties of suspension system such as camber angle, king-pin angle and track width alteration, which cannot be obtained from conventional quarter car suspension model, are evaluated in time and frequency domains. Finally, vibration control responses of the proposed suspension system are presented in time and frequency domains which are achieved from the semi-active sky-hook controller.

  12. A Feasibility Study. Ductless Hydronic Distribution Systems with Fan Coil Delivery

    SciTech Connect

    Springer, D.; Dakin, B.; Backman, C.

    2012-07-01

    The primary objectives of this study are to estimate potential energy savings relative to conventional ducted air distribution, and to identify equipment requirements, costs, and barriers with a focus on ductless hydronic delivery systems that utilize water-to-air terminal units in each zone. Results indicate that annual heating and cooling energy use can be reduced by up to 27% assuming replacement of the conventional 13 SEER heat pump and coil with a similarly rated air-to-water heat pump.

  13. Guidance of the divertor channel outside the main coil system for heliotron/torsatron devices

    NASA Astrophysics Data System (ADS)

    Takase, H.; Ohyabu, N.

    1995-02-01

    A divertor magnetic configuration is proposed that significantly reduces heat load on the divertor plates in heliotron/torsatron devices. The proposed configuration utilizes an octupole field for guiding the divertor channels to a remote area outside the main coil system, where the magnetic field is weak. This allows a significant reduction of the heat load due to expansion of the divertor channels as well as substantially easier access to the divertor plates for maintenance, the key requirements for toroidal fusion reactor designs

  14. A Digital Control Algorithm for Magnetic Suspension Systems

    NASA Technical Reports Server (NTRS)

    Britton, Thomas C.

    1996-01-01

    An ongoing program exists to investigate and develop magnetic suspension technologies and modelling techniques at NASA Langley Research Center. Presently, there is a laboratory-scale large air-gap suspension system capable of five degree-of-freedom (DOF) control that is operational and a six DOF system that is under development. Those systems levitate a cylindrical element containing a permanent magnet core above a planar array of electromagnets, which are used for levitation and control purposes. In order to evaluate various control approaches with those systems, the Generic Real-Time State-Space Controller (GRTSSC) software package was developed. That control software package allows the user to implement multiple control methods and allows for varied input/output commands. The development of the control algorithm is presented. The desired functionality of the software is discussed, including the ability to inject noise on sensor inputs and/or actuator outputs. Various limitations, common issues, and trade-offs are discussed including data format precision; the drawbacks of using either Direct Memory Access (DMA), interrupts, or program control techniques for data acquisition; and platform dependent concerns related to the portability of the software, such as memory addressing formats. Efforts to minimize overall controller loop-rate and a comparison of achievable controller sample rates are discussed. The implementation of a modular code structure is presented. The format for the controller input data file and the noise information file is presented. Controller input vector information is available for post-processing by mathematical analysis software such as MATLAB1.

  15. A new transcutaneous energy transmission system with hybrid energy coils for driving an implantable biventricular assist device.

    PubMed

    Okamoto, Eiji; Yamamoto, Yoshiro; Akasaka, Yuhta; Motomura, Tadashi; Mitamura, Yoshinori; Nosé, Yukihiko

    2009-08-01

    We have developed a new transcutaneous energy transmission (TET) system for a totally implantable biventricular assist device (BVAD) system in the New Energy and Industrial Development Organization (NEDO) artificial heart project. The TET system mainly consists of an energy transmitter, a hybrid energy coil unit, an energy receiver, an internal battery system, and an optical telemetry system. The hybrid energy coil unit consists of an air-core energy transmission coil and an energy-receiving coil having a ferrite core. Internal units of the TET system are encapsulated in a titanium alloy casing, which has a size of 111 mm in width, 73 mm in length, and 25 mm in height. In in vitro experiments, the TET system can transmit a maximum electric energy of 60 Watts, and it has a maximum transmission efficiency of 87.3%. A maximum surface temperature of 46.1 degrees C was measured at the ferrite core of the energy-receiving coil during an energy transmission of 20 Watts in air. The long-term performance test shows that the TET system has been able to operate stably for over 4 years with a decrease of energy-transmission efficiency from 85% to 80%. In conclusion, the TET system with the hybrid energy coil can overcome the drawback of previously reported TET systems, and it promises to be the highest performance TET system in the world.

  16. Progress of magnetic suspension systems and magnetic bearings in the USSR

    NASA Technical Reports Server (NTRS)

    Kuzin, A. V.

    1992-01-01

    This paper traces the development and progress of magnetic suspension systems and magnetic bearings in the USSR. The paper describes magnetic bearings for turbomachines, magnetic suspension systems for vibration isolation, some special measuring devices, wind tunnels, and other applications. The design, principles of operation, and dynamic characteristics of the system are presented.

  17. Heat pump systems with direct expansion ground coils

    NASA Astrophysics Data System (ADS)

    Svec, O. J.; Baxter, V. D.

    This paper is a summary of an International research project organized within the framework of the International Energy Agency (IEA), Implementing Agreement on Heat Pumps. This cooperative project, based on a task sharing principle, was proposed by the Canadian team and joined by the national teams of the United States of America, Japan and Austria. The Institute for Research in Construction (IRC) of the National Research Council of Canada (NRCC), has been acting as the Operating Agent for this project, known as Annex XV. The need for this research work is based on the recognition of the state-of-the-art of Ground Source Heat Pump (GSHP) technology, which can simply be described by the following two statements: (1) GSHP technology is the most successful among all renewable technologies in North American and northern European countries; and (2) installation cost of GSHP systems is currently too high for a meaningful worldwide penetration into the heating/cooling market.

  18. NCSX Toroidal Field Coil Design

    SciTech Connect

    Kalish, M.; Rushinski, J.; Myatt, L.; Brooks, A.; Dahlgren, F.; Chrzanowski, J.; Reiersen, W.; Freudenberg, K.

    2005-10-07

    The National Compact Stellarator Experiment (NCSX) is an experimental device whose design and construction is underway at the Department of Energy's Princeton Plasma Physics Laboratory (PPPL). The primary coil systems for the NCSX device consist of the twisted plasma-shaping Modular Coils, the Poloidal Field Coils, and the Toroidal Field (TF) Coils. The TF Coils are D-shaped coils wound from hollow copper conductor, and vacuum impregnated with a glass-epoxy resin system. There are 18 identical, equally spaced TF coils providing 1/R field at the plasma. They operate within a cryostat, and are cooled by LN2, nominally, to 80K. Wedge shaped castings are assembled to the inboard face of these coils, so that inward radial loads are reacted via the nesting of each of the coils against their adjacent partners. This paper outlines the TF Coil design methodology, reviews the analysis results, and summarizes how the design and analysis support the design requirements.

  19. A practical, low-noise coil system for magnetotellurics

    USGS Publications Warehouse

    Stanley, William D.; Tinkler, Richard D.

    1983-01-01

    Magnetotellurics is a geophysical technique which was developed by Cagnaird (1953) and Tikhonov (1950) and later refined by other scientists worldwide. The technique is a method of electromagnetic sounding of the Earth and is based upon the skin depth effect in conductive media. The electric and magnetic fields arising from natural sources are measured at the surface of the earth over broad frequency bands. An excellent review of the technique is provided in the paper by Vozoff (1972). The sources of the natural fields are found in two basic mechanisms. At frequencies above a few hertz, most of the energy arises from lightning in thunderstorm belts around the equatorial regions. This energy is propagated in a wave-guide formed by the earthionospheric cavity. Energy levels are higher at fundamental modes for this cavity, but sufficient energy exists over most of the audio range to be useful for sounding at these frequencies, in which case the technique is generally referred to as audio-magnetotellurics or AMT. At frequencies lower than audio, and in general below 1 Hz, the source of naturally occuring electromagnetic energy is found in ionospheric currents. Current systems flowing in the ionosphere generate EM waves which can be used in sounding of the earth. These fields generate a relatively complete spectrum of electromagnetic energy that extends from around 1 Hz to periods of one day. Figure 1 shows an amplitude spectrum characteristic of both the ionospheric and lightning sources, covering a frequency range from 0.0001 Hz to 1000 Hz. It can be seen that there is a minimum in signal levels that occurs at about 1 Hz, in the gap between the two sources, and that signal level increases with a decrease in frequency.

  20. Modeling and Control for an Asymmetric Hydraulic Active Suspension System

    NASA Astrophysics Data System (ADS)

    Kim, Wanil; Won, Sangchul

    In this paper we present a model for an automotive active suspension system which includes the dynamics of an asymmetric hydraulic actuator. In this model the force exerted by a single-rod cylinder is regarded as an internal state, and the sum of the oil flow rates through the orifice of a servo valve as the control input. We obtain a linear time-invariant (LTI) state state equation and propose a force-tracking-free one-step control method which can accept various linear control techniques. An optimal state-feedback control is applied as an example. Quarter car test rig experiment results show the effectiveness of the proposed approach in modeling and control.

  1. Development of rotating magnetic field coil system in the HIST spherical torus device

    NASA Astrophysics Data System (ADS)

    Yoshikawa, T.; Kikuchi, Y.; Yamada, S.; Hashimoto, S.; Nishioka, T.; Fukumoto, N.; Nagata, M.

    2007-11-01

    Coaxial Helicity Injection (CHI) is one of most attractive methods to achieve non-inductive current drive in spherical torus devices. The current drive mechanism of CHI relies on MHD relaxation process of rotating kink behavior [1], so that there is a possibility to control the CHI by using an externally applied rotating magnetic field (RMF). We have recently started to develop a RMF coil system in the HIST spherical torus device. Eight coils are located above and below the midplane at four toroidal locations so that the RMF is resonant with n = 1 rotating kink mode driven by the CHI. In addition, the RMF coil set is installed inside a flux conserver of 5 mm thickness (cut-off frequency ˜ 170 Hz) so that the RMF penetrates into the plasma. The coil winding is made of 20 turns of enameled copper circular wires (1.5 mm^2 conductor cross section), covered with a thin stainless steal case of 0.5 mm thickness (cut-off frequency ˜ 710 kHz). The RMF system is driven by an IGBT inverter power supply (nominal current: 1 kA, nominal voltage: 1 kV) with an operating frequency band from 10 kHz to 30 kHz. The estimated amplitude of RMF neglecting effects of image current at the flux conserver is a few tens Gauss at around the magnetic axis. A preliminary experimental result will be shown in the conference. [1] M. Nagata, et al., Physics of Plasmas 10, 2932 (2003).

  2. Energy expenditure estimate by heart-rate monitor and a portable electromagnetic coils system.

    PubMed

    Gastinger, Steven; Nicolas, Guillaume; Sorel, Anthony; Sefati, Hamid; Prioux, Jacques

    2012-04-01

    The aim of this article was to compare 2 portable devices (a heart-rate monitor and an electromagnetic-coil system) that evaluate 2 different physiological parameters--heart rate (HR) and ventilation (VE)--with the objective of estimating energy expenditure (EE). The authors set out to prove that VE is a more pertinent setting than HR to estimate EE during light to moderate activities (sitting and standing at rest and walking at 4, 5, and 6 km/hr). Eleven healthy men were recruited to take part in this study (27.6 ± 5.4 yr, 73.7 ± 9.7 kg). The authors determined the relationships between HR and EE and between VE and EE during light to moderate activities. They compared EE measured by indirect calorimetry (EEREF) with EE estimated by HR monitor (EEHR) and EE estimated by electromagnetic coils (EEMAG) in upright sitting and standing positions and during walking exercises. They compared EEREF with EEHR and EEMAG. The results showed no significant difference between the values of EEREF and EEMAG. However, they showed several significant differences between the values of EEREF and EEHR (for standing at rest and walking at 5 and 6 km/hr). These results showed that the electromagnetic-coil system seems to be more accurate than the HR monitor to estimate EE at rest and during exercise. Taking into consideration these results, it would be interesting to associate the parameters VE and HR to estimate EE. Furthermore, a new version of the electromagnetic-coil device was recently developed and provides the possibility to perform measurement under daily life conditions.

  3. MRI compatibility study of an integrated PET/RF-coil prototype system at 3T.

    PubMed

    Akram, Md Shahadat Hossain; Obata, Takayuki; Suga, Mikio; Nishikido, Fumihiko; Yoshida, Eiji; Saito, Kazuyuki; Yamaya, Taiga

    2017-10-01

    We have been working on the development of a PET insert for existing magnetic resonance imaging (MRI) systems for simultaneous PET/MR imaging, which integrates radiofrequency (RF)-shielded PET detector modules with an RF head coil. In order to avoid interferences between the PET detector circuits and the different MRI-generated electromagnetic fields, PET detector circuits were installed inside eight Cu-shielded fiber-reinforced plastic boxes, and these eight shielded PET modules were integrated in between the eight elements of a 270-mm-diameter and 280-mm-axial-length cylindrical birdcage RF coil, which was designed to be used with a 3-T clinical MRI system. The diameter of the PET scintillators with a 12-mm axial field-of-view became 255mm, which was very close to the imaging region. In this study, we have investigated the effects of this PET/RF-coil integrated system on the performance of MRI, which include the evaluation of static field (Bo) inhomogeneity, RF field (B1) distribution, local specific absorption rate (SAR) distribution, average SAR, and signal-to-noise ratio (SNR). For the central 170-mm-diameter and 80-mm-axial-length of a homogenous cylindrical phantom (with the total diameter of 200mm and axial-length of 100mm), an increase of about a maximum of 3μT in the Bo inhomogeneity was found, both in the central and 40-mm off-centered transverse planes, and a 5 percentage point increase of B1 field inhomogeneity was observed in the central transverse plane (from 84% without PET to 79% with PET), while B1 homogeneity along the coronal plane was almost unchanged (77%) following the integration of PET with the RF head coil. The average SAR and maximum local SAR were increased by 1.21 and 1.62 times, respectively. However, the SNR study for both spin-echo and gradient-echo sequences showed a reduction of about 70% and 60%, respectively, because of the shielded PET modules. The overall results prove the feasibility of this integrated PET/RF-coil system for

  4. [Establishment of a cell suspension culture system of endangered Aquilaria sinensis (Lour.) Gilg].

    PubMed

    Liu, Juan; Han, Xiao-Min; Liang, Liang; Liu, Qing-Chang; Xu, Yan-Hong; Yang, Cheng-Min; Zhang, Zheng; Sun, Jing; Wei, Jian-He

    2014-08-01

    Aquilaria sinensis callus induced by stem tips were used to establish the suspension cell system. The results showed that the most suitable medium for callus induction and subculture is MS + 2.0 mg x L(-1) NAA + 1.0 mg x L(-1) 6-BA. After 12 times of subculture, the energetic and loose callus, which were appropriate for cell suspension culture, were cultured and shook in liquid medium MS + 2.0 mg x L(-1) NAA + 1.0 mg x L(-1) 6-BA + 500.0 mg x L(-1) casein hydrolysate (CH) to establish the suspension cell system. The growth curve of suspension cells showed a "S" type. At the beginning of the culture, cell density increased slowly; during 4 to 6 days, suspension cells reached logarithmic growth period; during 7 to 12 days, suspension cells were in the platform period; but after 12 days, cell density and activity went down obviously. Agarwood sesquiterpenes were not detected in the suspension cells during the growth period, however, they could be detected in MeJA treated suspension cells. In this study, a stable and active growing suspension cell system was established, which was a proper system to study the mechanism of agarwood sesquiterpene formation, and additionally provided a potential way to generate agarwood sesquiterpenes through application of cell culture.

  5. A voice coil actuator driven active vibration isolation system with the consideration of flexible modes

    NASA Astrophysics Data System (ADS)

    Park, Kyihwan; Choi, Dongyoub; Ozer, Abdullah; Kim, Sangyoo; Lee, Yongkwan; Joo, Dongik

    2008-06-01

    We develop a four-mount active vibration isolation system (AVIS) using voice coil actuators. The flexible body modes in the upper plate of the AVIS can cause an instability problem due to control signal whose frequency is close to the resonant frequency of the flexible modes. The loop shaping technique is applied to reduce the amplitude of the control signal. We investigate the performances of the active vibration isolation system proposed in the word in the time domain and frequency domain by comparing to the passive isolation system.

  6. A voice coil actuator driven active vibration isolation system with the consideration of flexible modes.

    PubMed

    Park, Kyihwan; Choi, Dongyoub; Ozer, Abdullah; Kim, Sangyoo; Lee, Yongkwan; Joo, Dongik

    2008-06-01

    We develop a four-mount active vibration isolation system (AVIS) using voice coil actuators. The flexible body modes in the upper plate of the AVIS can cause an instability problem due to control signal whose frequency is close to the resonant frequency of the flexible modes. The loop shaping technique is applied to reduce the amplitude of the control signal. We investigate the performances of the active vibration isolation system proposed in the word in the time domain and frequency domain by comparing to the passive isolation system.

  7. Performance of large-size superconducting coil in 0.21T MRI system.

    PubMed

    Lee, K H; Cheng, M C; Chan, K C; Wong, K K; Yeung, Simon S M; Lee, K C; Ma, Q Y; Yang, Edward S

    2004-11-01

    A high-temperature superconductor (HTS) was used on magnetic resonance imaging (MRI) receiver coils to improve image quality because of its intrinsic low electrical resistivity. Typical HTS coils are surface coils made of HTS thin-film wafers. Their applications are severely limited by the field of view (FOV) of the surface coil configuration, and the improvement in image quality by HTS coil is also reduced as the ratio of sample noise to coil noise increases. Therefore, previous HTS coils are usually used to image small in vitro samples, small animals, or peripheral human anatomies. We used large-size HTS coils (2.5-, 3.5-, and 5.5-in mean diameter) to enhance the FOV and we evaluated their performance through phantom and human MR images. Comparisons were made among HTS surface coils, copper surface coils, and cool copper surface coils in terms of the signal-to-noise ratio (SNR) and sensitivity profile of the images. A theoretical model prediction was also used to compare against the experimental result. We then selected several human body parts, including the wrist, feet, and head, to illustrate the advantage of HTS coil over copper coil when used in human imaging. The results show an SNR gain of 200% for 5.5-in HTS coil versus same size copper coils, while for 2.5- and 3.5-in coils it is 250%. We also address the various factors that affect the performance of large size HTS coils, including the coil-to-sample spacing due to cryogenic probe and the coil-loading effect.

  8. Mountain Plains Learning Experience Guide: Automotive Repair. Course: Suspension Systems.

    ERIC Educational Resources Information Center

    Schramm, C.; Osland, Walt

    One of twelve individualized courses included in an automotive repair curriculum, this course covers the theory, maintenance, and repair of front-end suspension and steering mechanisms. The course is comprised of five units: (1) Tire Balancing, (2) Manual Steering Gears, (3) Power Steering, (4) Fundamentals of Suspension, and (5) Front-End…

  9. A review of Magnetic Suspension and Balance Systems

    NASA Technical Reports Server (NTRS)

    Boyden, Richmond P.

    1988-01-01

    This paper traces the development of Magnetic Suspension and Balance Systems (MSBSs) for use in wind tunnels. The expression MSBS implies a system that can both suspend a model and also measure the forces and moments acting on the model. This avoids the need for any mechanical support of the model. An MSBS uses electromagnets located outside the test section walls to create magnetic fields inside the test section. Measurement of the electrical current flowing in each of the electromagnets can be used to determine the forces and moments acting on the suspended model. An MSBS is capable of supporting a model with an internal magnetized core subject to gravity, aerodynamic, and inertial loads. The model must have a core made of either a permanent magnet, magnetized soft iron, or a solenoid. The position of the suspended body is inherently unstable. A closed-loop control system which includes a position sensing system has to control the position of the body by controlling the applied magnetic fields. This paper includes a discussion of all the known MSBSs and the outlook for larger systems.

  10. Optimal secondary coil design for inductive powering of the Artificial Accommodation System.

    PubMed

    Nagel, J A; Krug, M; Gengenbach, U; Guth, H; Bretthauer, G; Guthoff, R F

    2011-01-01

    Age-related ailments like presbyopia and cataract are increasing concerns in the aging society. Both go along with a loss of ability to accommodate. A new approach to restore the patients' ability to accommodate is the Artificial Accommodation System. This micro mechatronic system will be implanted into the capsular bag to replace the human crystalline lens. Depending on the patients' actual need for accommodation, the Artificial Accommodation System autonomously adapts the refractive power of its integrated optical element in a way that the projection on the patients' retina results in a sharp image. As the Artificial Accommodation System is an active implant, its subsystems have to be supplied with electrical energy. Evolving technologies, like energy harvesting, which can potentially be used to power an implant like the Artificial Accommodation System are at the current state of art not sufficient to power the Artificial Accommodation System autonomously [1]. In the near future, therefore an inductive power supply system will be developed which includes an energy storage to power the Artificial Accommodation System autonomously over a period of 24 h and can be recharged wirelessly. This Paper describes a new possibility to optimize the secondary coil design in a solely analytical way, based on a new figure of merit. Within this paper the developed figure of merit is applied to optimize the secondary coil design for the Artificial Accommodation System.

  11. Active control of an innovative seat suspension system with acceleration measurement based friction estimation

    NASA Astrophysics Data System (ADS)

    Ning, Donghong; Sun, Shuaishuai; Li, Hongyi; Du, Haiping; Li, Weihua

    2016-12-01

    In this paper, an innovative active seat suspension system for vehicles is presented. This seat suspension prototype is built with two low cost actuators each of which has one rotary motor and one gear reducer. A H∞ controller with friction compensation is designed for the seat suspension control system where the friction is estimated and compensated based on the measurement of seat acceleration. This principal aim of this research was to control the low frequency vibration transferred or amplified by the vehicle (chassis) suspension, and to maintain the passivity of the seat suspension at high frequency (isolation vibration) while taking into consideration the trade-off between the active seat suspension cost and its high frequency performance. Sinusoidal excitations of 1-4.5 Hz were applied to test the active seat suspension both when controlled and when uncontrolled and this is compared with a well-tuned passive heavy duty vehicle seat suspension. The results indicate the effectiveness of the proposed control algorithm within the tested frequencies. Further tests were conducted using the excitations generated from a quarter-car model under bump and random road profiles. The bump road tests indicate the controlled active seat suspension has good transient response performance. The Power Spectral Density (PSD) method and ISO 2631-1 standards were applied to analyse the seat suspension's acceleration under random road conditions. Although some low magnitude and high frequency noise will inevitably be introduced by the active system, the weighted-frequency Root Mean Square (RMS) acceleration shows that this may not have a large effect on ride comfort. In fact, the ride comfort is improved from being an 'a little uncomfortable' to a 'not uncomfortable' level when compared with the well-tuned passive seat suspension. This low cost active seat suspension design and the proposed controller with the easily measured feedback signals are very practical for real

  12. The Stiffness Characteristics Study on an Interconnected Anti-Rolling Suspension System

    NASA Astrophysics Data System (ADS)

    Hou, Youshan; Song, Huixin; Ma, Ming; Xiao, Jie; Zhao, Ning

    The heavy-duty special vehicles easily roll during steering, anti-rolling technology becomes a critical technology to the heavy-duty vehicles. Aiming at the rolling problem of a full load heavy vehicle in the process of steering, an interconnected anti-rolling suspension system with adjustable damping was designed, the nonlinear stiffness mathematical model of interconnected anti-rolling suspension system was established. The stiffness characteristic was studied through digital simulation method, discussing the system parameter changes' affection on the stiffness performance of interconnected anti-rolling suspension system. The study results indicate that the interconnected anti-rolling suspension system betterly improves vehicles rolling resistance in contrast to the oil-gas mixed independent suspension, the study results provide theoretical basis for the anti-rolling's design of heavy-duty vehicles.

  13. Multiple frequency MR implantable coil system for in vivo studies of bioartificial pancreas at 11.1 T

    NASA Astrophysics Data System (ADS)

    Volland, N. A.; Taylor, C. A.; Mareci, T. H.; Constantinidis, I.

    2005-11-01

    Bioartificial pancreatic macroconstructs may deliver insulin secreting cells for blood glucose regulation. Non-invasively monitoring in vivo is key to understanding its function and efficacy. Initial NMR imaging & spectroscopy showed great promise with surface coils at 4.7 T. Sensitivity limitations restrict measurements so we developed an inductively-coupled multiple-frequency coil system for 11.1 T. This system contains an implantable loop-gap resonator, inductively coupled to an external coil, resonating at 471 MHz for ^1H and optimized for ^31P at 191 MHz. This system has a sensitivity gain of ˜5.2 (±2.3) over a surface coil. Images were acquired for both frequencies. Ongoing work focuses on: 1) a receive-only coil system, 2) adding a third resonance (443 MHz for ^19F), and 3) developing coating material and embedding the implantable coil in the macroconstruct. This system will be characterized in vitro prior to its use in vivo.

  14. Tests of insulation systems for Nb3Sn wind and react coils

    SciTech Connect

    Bossert, R.; Ambrosio, G; Andreev, N.; Whitson, G.; Zlobin, A.; /Fermilab

    2007-07-01

    Tests were performed to assess the viability of several cable insulation systems for use in Nb{sub 3}Sn accelerator magnets. Insulated stacks of cables were subjected to reaction cycles commonly used for Nb{sub 3}Sn coils. After reaction and epoxy impregnation, current leakage between turns was measured at pressures up to 180 MPa and turn-to-turn potentials up to 500V. Systems consisting of S-2 glass, ceramic fiber, and E-glass were tested. Several methods of applying the insulation were incorporated, including sleeves and various spiral wrapped configurations. Methods of sample preparation and testing are described and results are reported.

  15. Tests of Insulation Systems for Nb3SN Wind and React Coils

    NASA Astrophysics Data System (ADS)

    Bossert, R.; Ambrosio, G.; Andreev, N.; Whitson, G.; Zlobin, A.

    2008-03-01

    Tests were performed to assess the viability of several cable insulation systems for use in Nb3Sn accelerator magnets. Insulated stacks of cables were subjected to reaction cycles commonly used for Nb3Sn coils. After reaction and epoxy impregnation, current leakage between turns was measured at pressures up to 180 MPa and turn-to-turn potentials up to 500 V. Systems consisting of S-2 glass, ceramic fiber, and E-glass were tested. Several methods of applying the insulation were incorporated, including sleeves and various spiral wrapped configurations. Methods of sample preparation and testing are described and results are reported.

  16. Development of superconducting magnetic bearing with superconducting coil and bulk superconductor for flywheel energy storage system

    NASA Astrophysics Data System (ADS)

    Arai, Y.; Seino, H.; Yoshizawa, K.; Nagashima, K.

    2013-11-01

    We have been developing superconducting magnetic bearing for flywheel energy storage system to be applied to the railway system. The bearing consists of a superconducting coil as a stator and bulk superconductors as a rotor. A flywheel disk connected to the bulk superconductors is suspended contactless by superconducting magnetic bearings (SMBs). We have manufactured a small scale device equipped with the SMB. The flywheel was rotated contactless over 2000 rpm which was a frequency between its rigid body mode and elastic mode. The feasibility of this SMB structure was demonstrated.

  17. Human Factors Assessment of U.S. Marine Lightweight Helmet Suspension Systems: Standard A Pad System vs. a Proposed Suspension System B HeadGard

    DTIC Science & Technology

    2011-09-01

    Other devices used to measure the body are calipers and linen tapes (figure 6). Calipers are used to measure dimensions of the head and hands. Linen ... linen tape. 9 4. Procedures Twenty-four U.S. Marines participated in the helmet suspension system assessment during which they carried an inert M4

  18. Gold enrichment in active geothermal systems by accumulating colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Hannington, Mark; Harðardóttir, Vigdis; Garbe-Schönberg, Dieter; Brown, Kevin L.

    2016-04-01

    The origins of high-grade hydrothermal ore deposits are debated, but active geothermal systems provide important clues to their formation. The highest concentrations of gold are found in geothermal systems with direct links to island arc magmatism. Yet, similar concentrations have also been found in the absence of any input from arc magmas, for example, in the Reykjanes geothermal field, Iceland. Here we analyse brine samples taken from deep wells at Reykjanes and find that gold concentrations in the reservoir zone have increased over the past seven years from an average of 3 ppb to 14 ppb. The metal concentrations greatly exceed the maximum solubility of gold in the reservoir under saturated conditions and are now nearly two orders of magnitude higher than in mid-ocean ridge black smoker fluids--the direct analogues of Reykjanes deep liquids. We suggest that ongoing extraction of brine, the resulting pressure drop, and increased boiling have caused gold to drop out of solution and become trapped in the reservoir as a colloidal suspension. This process may explain how the stock of metal in the reservoirs of fossil geothermal systems could have increased over time and thus become available for the formation of gold-rich ore deposits.

  19. An accurate online calibration system based on combined clamp-shape coil for high voltage electronic current transformers

    SciTech Connect

    Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi

    2013-07-15

    Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.

  20. An accurate online calibration system based on combined clamp-shape coil for high voltage electronic current transformers

    NASA Astrophysics Data System (ADS)

    Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi

    2013-07-01

    Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.

  1. An accurate online calibration system based on combined clamp-shape coil for high voltage electronic current transformers.

    PubMed

    Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi

    2013-07-01

    Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.

  2. Characterising nuclear simulant suspensions in situ with an acoustic backscatter system

    SciTech Connect

    Bux, Jaiyana; Hunter, Timothy N.; Paul, Neepa; Biggs, Simon R.; Dodds, Jonathan M.; Peakall, Jeffrey

    2013-07-01

    In situ characterisation of radio-toxic sludges and slurries is critical to numerous operations including those involving their transport and retrieval. An inexpensive, flexible acoustic backscatter system has been employed for the first time here to a 4/10. scale active storage tank comprising of a nuclear simulant suspension, to verify its application. Intricate suspension characteristics and tank operation features emerged. (authors)

  3. 21 CFR 1404.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 9 2014-04-01 2014-04-01 false What is the purpose of the nonprocurement debarment and suspension system? 1404.110 Section 1404.110 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General § 1404.110 What is the purpose...

  4. 21 CFR 1404.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false What is the purpose of the nonprocurement debarment and suspension system? 1404.110 Section 1404.110 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General § 1404.110 What is the purpose...

  5. 21 CFR 1404.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false What is the purpose of the nonprocurement debarment and suspension system? 1404.110 Section 1404.110 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General § 1404.110 What is the purpose...

  6. 21 CFR 1404.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false What is the purpose of the nonprocurement debarment and suspension system? 1404.110 Section 1404.110 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General § 1404.110 What is the purpose...

  7. 21 CFR 1404.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false What is the purpose of the nonprocurement debarment and suspension system? 1404.110 Section 1404.110 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General § 1404.110 What is the purpose...

  8. Analysis of Semi-Active and Passive Suspensions System for Off-Road Vehicles

    NASA Astrophysics Data System (ADS)

    BenLahcene, Zohir; Faris, Waleed F.; Khan, M. D. Raisuddin

    2009-03-01

    The speed of off-road vehicles over rough terrain is generally determined by the ride quality not by the engine power. For this reason, researches are currently being undertaking to improve the ride dynamics of these vehicles using an advanced suspension system. This study intends to provide a preliminary evaluation of whether semi-active suspensions are beneficial to improving ride and handling in off-road vehicles. One of the greatest challenges in designing off-road vehicle suspension system is maintaining a good balance between vehicle ride and handling. Three configurations of these vehicles; 2-axle, 3-xle and 4-axles have been studied and their performances are compared. The application of several control policies of semi-active suspension system, namely skyhook; ground-hook and hybrid controls have been analyzed and compared with passive systems. The results show that the hybrid control policy yields better comfort than a passive suspension, without reducing the road-holding quality or increasing the suspension displacement. The hybrid control policy is also shown to be a better compromise between comfort, road-holding and suspension displacement than the skyhook and ground-hook control policies. Results show an improvement in ride comfort and vehicle handling using 4-axle over 3-axle and 2-axle when emphasis is placed on the response of the vehicle body acceleration, suspension and tyre deflection.

  9. 22 CFR 1508.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true What is the purpose of the nonprocurement debarment and suspension system? 1508.110 Section 1508.110 Foreign Relations AFRICAN DEVELOPMENT FOUNDATION GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) General § 1508.110 What is the purpose of the...

  10. Nonlinear compensation techniques for magnetic suspension systems. Ph.D. Thesis - MIT

    NASA Technical Reports Server (NTRS)

    Trumper, David L.

    1991-01-01

    In aerospace applications, magnetic suspension systems may be required to operate over large variations in air-gap. Thus the nonlinearities inherent in most types of suspensions have a significant effect. Specifically, large variations in operating point may make it difficult to design a linear controller which gives satisfactory stability and performance over a large range of operating points. One way to address this problem is through the use of nonlinear compensation techniques such as feedback linearization. Nonlinear compensators have received limited attention in the magnetic suspension literature. In recent years, progress has been made in the theory of nonlinear control systems, and in the sub-area of feedback linearization. The idea is demonstrated of feedback linearization using a second order suspension system. In the context of the second order suspension, sampling rate issues in the implementation of feedback linearization are examined through simulation.

  11. Electromechanical design and construction of a rotating radio-frequency coil system for applications in magnetic resonance.

    PubMed

    Trakic, Adnan; Weber, Ewald; Li, Bing Keong; Wang, Hua; Liu, Feng; Engstrom, Craig; Crozier, Stuart

    2012-04-01

    While recent studies have shown that rotating a single radio-frequency (RF) coil during the acquisition of magnetic resonance (MR) images provides a number of hardware advantages (i.e., requires only one RF channel, avoids coil-coil coupling and facilitates large-scale multinuclear imaging), they did not describe in detail how to build a rotating RF coil system. This paper presents detailed engineering information on the electromechanical design and construction of a MR-compatible RRFC system for human head imaging at 2 T. A custom-made (bladeless) pneumatic Tesla turbine was used to rotate the RF coil at a constant velocity, while an infrared optical encoder measured the selected frequency of rotation. Once the rotating structure was mechanically balanced and the compressed air supply suitably regulated, the maximum frequency of rotation measured ~14.5 Hz with a 2.4% frequency variation over time. MR images of a water phantom and human head were obtained using the rotating RF head coil system.

  12. A Flexible Integrated System Containing a Microsupercapacitor, a Photodetector, and a Wireless Charging Coil.

    PubMed

    Yue, Yang; Yang, Zhichun; Liu, Nishuang; Liu, Weijie; Zhang, Hui; Ma, Yanan; Yang, Congxing; Su, Jun; Li, Luying; Long, Fei; Zou, Zhengguang; Gao, Yihua

    2016-12-27

    Nowadays, the integrated systems on a plane substrate containing energy harvesting, energy storing, and working units are strongly desired with the fast development of wearable and portable devices. Here, a simple, low cost, and scalable strategy involving ink printing and electrochemical deposition is proposed to fabricate a flexible integrated system on a plane substrate containing an all-solid-state asymmetric microsupercapacitor (MSC), a photoconduct-type photodetector of perovskite nanowires (NWs), and a wireless charging coil. In the asymmetric MSCs, MnO2-PPy and V2O5-PANI composites are used as positive and negative electrodes, respectively. Typical values of energy density in the range of 15-20 mWh cm(-3) at power densities of 0.3-2.5 W cm(-3) with an operation potential window of 1.6 V are achieved. In the system, the wireless charging coil receives energy from a wireless power transmitter, which then can be stored in the MSC to drive the photoconductive detector of perovskite NWs in sequence. The designed integrated system exhibits a stable photocurrent response comparable with the detector driven by an external power source. This research provides an important routine to fabricate integrated systems.

  13. A new metal detection method based on balanced coil for mobile phone wireless charging system

    NASA Astrophysics Data System (ADS)

    Zhou, B.; Liu, Z. Z.; Chen, H. X.; Zeng, H.; Hei, T.

    2016-08-01

    The wireless charging time of mobile phone will increase greatly if the metal objects mix in the magnetic field coupling area. In addition, the fire may be caused as for the high temperature of metal objects. The paper proposed an improved detecting method based on balance coil for mobile phone wireless charging system according to comparing the advantages and disadvantages of traditional metal detection methods. The circuit model was established, and hardware and software were optimized. At last, experimental results verified the theoretical analysis.

  14. Interchangeable neck shape-specific coils for a clinically realizable anterior neck phased array system.

    PubMed

    Beck, Michael J; Parker, Dennis L; Bolster, Bradley D; Kim, Seong-Eun; McNally, J Scott; Treiman, Gerald S; Hadley, J Rock

    2017-02-10

    To demonstrate the interchangeable neck shape-specific (NSS) coil concept that supplements standard commercial spine and head/neck coils to provide simultaneous high-resolution (hi-res) head/neck imaging with high signal-to-noise ratio (SNR). Two NSS coils were constructed on formers designed to fit two different neck shapes. A 7-channel (7ch) ladder array was constructed on a medium neck former, and a 9-channel (9ch) ladder array was constructed on large neck former. Both coils were interchangeable with the same preamp housing. The 7ch and 9ch coils demonstrate SNR gains of approximately 4 times and 3 times over the Siemens 20-channel head/neck coil in the carotid arteries of our volunteers, respectively. Coupling between the Siemens 32-channel spine coil, Siemens 20-channel head/neck coil, and the NSS coils was negligible, allowing for simultaneous hi-res head/neck imaging with high SNR. This study demonstrates that supplementing existing commercial spine and head/neck coils with an NSS coil allows uniform simultaneous hi-res imaging with high SNR in the anterior neck, while maintaining SNR of the commercial coil in the head and posterior neck. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  15. Heterotrimeric Coiled Coils with Core Residue Urea Side Chains

    PubMed Central

    Diss, Maria L.; Kennan, Alan J.

    2009-01-01

    We report several coiled coil heterotrimers with varying core residue buried polar groups, all with Tm values > 43° C. Introduction of new synthetic side chain structures, including some terminating in mono-substituted ureas, diversifies the pool of viable core residue candidates. A study of core charge pairings demonstrates that, unlike dimeric systems, trimeric coiled coils do not tolerate guanidine-guanidine contacts, even in the presence of a compensating carboxylate. Overall, the roster of feasible coiled coil designs is significantly expanded. PMID:19032043

  16. Comparison of digital controllers used in magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Kilgore, William A.

    1990-01-01

    Dynamic systems that were once controlled by analog circuits are now controlled by digital computers. Presented is a comparison of the digital controllers presently used with magnetic suspension and balance systems. The overall responses of the systems are compared using a computer simulation of the magnetic suspension and balance system and the digital controllers. The comparisons include responses to both simulated force and position inputs. A preferred digital controller is determined from the simulated responses.

  17. Potential benefits of magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Lawing, Pierce L.; Dress, David A.; Kilgore, Robert A.

    1987-01-01

    The potential of Magnetic Suspension and Balance Systems (MSBS) to improve conventional wind tunnel testing techniques is discussed. Topics include: elimination of model geometry distortion and support interference to improve the measurement accuracy of aerodynamic coefficients; removal of testing restrictions due to supports; improved dynamic stability data; and stores separation testing. Substantial increases in wind tunnel productivity are anticipated due to the coalescence of these improvements. Specific improvements in testing methods for missiles, helicopters, fighter aircraft, twin fuselage transports and bombers, state separation, water tunnels, and automobiles are also forecast. In a more speculative vein, new wind tunnel test techniques are envisioned as a result of applying MSBS, including free-flight computer trajectories in the test section, pilot-in-the-loop and designer-in-the-loop testing, shipboard missile launch simulation, and optimization of hybrid hypersonic configurations. Also addressed are potential applications of MSBS to such diverse technologies as medical research and practice, industrial robotics, space weaponry, and ore processing in space.

  18. Robust SMES controller design for stabilization of inter-area oscillation considering coil size and system uncertainties

    NASA Astrophysics Data System (ADS)

    Ngamroo, Issarachai

    2010-12-01

    It is well known that the superconducting magnetic energy storage (SMES) is able to quickly exchange active and reactive power with the power system. The SMES is expected to be the smart storage device for power system stabilization. Although the stabilizing effect of SMES is significant, the SMES is quite costly. Particularly, the superconducting magnetic coil size which is the essence of the SMES, must be carefully selected. On the other hand, various generation and load changes, unpredictable network structure, etc., cause system uncertainties. The power controller of SMES which is designed without considering such uncertainties, may not tolerate and loses stabilizing effect. To overcome these problems, this paper proposes the new design of robust SMES controller taking coil size and system uncertainties into account. The structure of the active and reactive power controllers is the 1st-order lead-lag compensator. No need for the exact mathematical representation, system uncertainties are modeled by the inverse input multiplicative perturbation. Without the difficulty of the trade-off of damping performance and robustness, the optimization problem of control parameters is formulated. The particle swarm optimization is used for solving the optimal parameters at each coil size automatically. Based on the normalized integral square error index and the consideration of coil current constraint, the robust SMES with the smallest coil size which still provides the satisfactory stabilizing effect, can be achieved. Simulation studies in the two-area four-machine interconnected power system show the superior robustness of the proposed robust SMES with the smallest coil size under various operating conditions over the non-robust SMES with large coil size.

  19. Suspension and Debarment Regulations

    EPA Pesticide Factsheets

    Governmentwide Nonprocurement Suspension and Debarment Guidelines and EPA Implementation. Executive Order 12549 provides for a governmentwide system of nonprocurment (grants and cooperative agreements) debarment and suspension.

  20. Integrated analysis of quench propagation in a system of magnetically coupled superconducting coils

    NASA Astrophysics Data System (ADS)

    Marinucci, Claudio; Bottura, Luca; Calvi, Marco

    2013-01-01

    We demonstrate in this paper how to use direct modeling of heat transfer and circuital equations based on "packaged" simulation tools to produce a model suitable for the study of quench propagation in a system of magnetically coupled solenoids protected without an external dump resistor. Our application example is a system of three, layer-wound and bath-cooled coils, all using a NbTi conductor. The same model can be easily adapted to study coils with different topologies, geometry and conductors. We demonstrate the use of the model by parametric analysis of physical parameters in the system, showing under which conditions a quench-back due to inductive coupling is triggered. The results, and in particular longitudinal and transverse propagation velocities, are consistent with expected analytical scalings. The advantage of the model is that it provides self-consistent results, i.e. based on first principles rather than assumptions on quench propagation, and it gives access to local details that are not intuitive, nor easily measurable.

  1. Structural and biochemical characterizations of an intramolecular tandem coiled coil protein.

    PubMed

    Shin, Donghyuk; Kim, Gwanho; Kim, Gyuhee; Zheng, Xu; Kim, Yang-Gyun; Lee, Sangho

    2014-12-12

    Coiled coil has served as an excellent model system for studying protein folding and developing protein-based biomaterials. Most designed coiled coils function as oligomers, namely intermolecular coiled coils. However, less is known about structural and biochemical behavior of intramolecular coiled coils where coiled coil domains are covalently linked in one polypeptide. Here we prepare a protein which harbors three coiled coil domains with two short linkers, termed intramolecular tandem coiled coil (ITCC) and characterize its structural and biochemical behavior in solution. ITCC consists of three coiled coil domains whose sequences are derived from Coil-Ser and its domain swapped dimer. Modifications include positioning E (Glu) residue at "e" and K (Lys) at "g" positions throughout heptad repeats to enhance ionic interaction among its constituent coiled coil domains. Molecular modeling of ITCC suggests a compact triple helical bundle structure with the second and the third coiled coil domains forming a canonical coiled coil. ITCC exists as a mixture of monomeric and dimeric species in solution. Small-angle X-ray scattering reveals ellipsoidal molecular envelopes for both dimeric and monomeric ITCC in solution. The theoretically modeled structures of ITCC dock well into the envelopes of both species. Higher ionic strength shifts the equilibrium into monomer with apparently more compact structure while secondary structure remains unchanged. Taken together, our results suggest that our designed ITCC is predominantly monomeric structure through the enhanced ionic interactions, and its conformation is affected by the concentration of ionic species in the buffer.

  2. Kinematic Kevlar suspension system for the HAWC and SAFIRE ADR salt pills

    NASA Astrophysics Data System (ADS)

    Voellmer, George M.; Jackson, Michael; Shirron, Peter J.; Tuttle, James G.

    2003-03-01

    The High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter And Far Infrared Experiment (SAFIRE) will use identical Adiabatic Demagnetization Refrigerators (ADR) to cool their detectors to 200mK and 100mK, respectively. In order to minimize thermal loads on the salt pill, a Kevlar® suspension system is used to hold it in place. An innovative, kinematic suspension system is presented. The suspension system is unique in that it consists of two parts that can be assembled and tensioned offline, and later bolted onto the salt pill.

  3. A superconducting large-angle magnetic suspension

    NASA Technical Reports Server (NTRS)

    Downer, James; Goldie, James; Torti, Richard

    1991-01-01

    The component technologies were developed required for an advanced control moment gyro (CMG) type of slewing actuator for large payloads. The key component of the CMG is a large-angle magnetic suspension (LAMS). The LAMS combines the functions of the gimbal structure, torque motors, and rotor bearings of a CMG. The LAMS uses a single superconducting source coil and an array of cryoresistive control coils to produce a specific output torque more than an order of magnitude greater than conventional devices. The designed and tested LAMS system is based around an available superconducting solenoid, an array of twelve room-temperature normal control coils, and a multi-input, multi-output control system. The control laws were demonstrated for stabilizing and controlling the LAMS system.

  4. Functional Based Adaptive and Fuzzy Sliding Controller for Non-Autonomous Active Suspension System

    NASA Astrophysics Data System (ADS)

    Huang, Shiuh-Jer; Chen, Hung-Yi

    In this paper, an adaptive sliding controller is developed for controlling a vehicle active suspension system. The functional approximation technique is employed to substitute the unknown non-autonomous functions of the suspension system and release the model-based requirement of sliding mode control algorithm. In order to improve the control performance and reduce the implementation problem, a fuzzy strategy with online learning ability is added to compensate the functional approximation error. The update laws of the functional approximation coefficients and the fuzzy tuning parameters are derived from the Lyapunov theorem to guarantee the system stability. The proposed controller is implemented on a quarter-car hydraulic actuating active suspension system test-rig. The experimental results show that the proposed controller suppresses the oscillation amplitude of the suspension system effectively.

  5. Effects of flexibility on AGS performance. [Annular suspension pointing system Gimbal System aboard Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Shelton, H. L.; Cunningham, D. C.; Worley, H. E.; Seltzer, S. M.

    1982-01-01

    The Marshall Space Flight Center has had under development the Annular Suspension Pointing System Gimbal System (AGS) since early 1979. The AGS is an Orbiter cargo bay mounted subarcsecond 3 axis inertial pointer that can accommodate a wide range of payloads which require more stringent pointing than the Orbiter can provide. This paper will describe the AGS, state performance requirements and the control law configuration. Then an approach to investigating the flexible body effects on control system design will be discussed.

  6. Design of ground test suspension systems for verification of flexible space structures

    NASA Technical Reports Server (NTRS)

    Cooley, V. M.; Juang, J. N.; Ghaemmaghami, P.

    1988-01-01

    A simple model demonstrates the frequency-increasing effects of a simple cable suspension on flexible test article/suspension systems. Two passive suspension designs, namely a negative spring mechanism and a rolling cart mechanism, are presented to alleviate the undesirable frequency-increasing effects. Analysis methods are provided for systems in which the augmentations are applied to both discrete and continuous representations of test articles. The damping analyses are based on friction equivalent viscous damping. Numerical examples are given for comparing the two augmentations with respect to minimizing frequency and damping increases.

  7. Rethinking Suspensions

    ERIC Educational Resources Information Center

    Stetson, Frank H.; Collins, Betty J.

    2010-01-01

    The overrepresentation of the Black and Hispanic subgroups in suspension data is a national problem and a troubling issue for schools and school systems across the United States. In Maryland, an analysis of student suspensions by school districts for the 2006-2007 school year revealed disproportionality issues. In 23 of the 24 jurisdictions,…

  8. Rethinking Suspensions

    ERIC Educational Resources Information Center

    Stetson, Frank H.; Collins, Betty J.

    2010-01-01

    The overrepresentation of the Black and Hispanic subgroups in suspension data is a national problem and a troubling issue for schools and school systems across the United States. In Maryland, an analysis of student suspensions by school districts for the 2006-2007 school year revealed disproportionality issues. In 23 of the 24 jurisdictions,…

  9. Expert diagnostic system for moving-coil loudspeakers using nonlinear modeling.

    PubMed

    Bai, Mingsian R; Huang, Chau-Min

    2009-02-01

    This work aims at the development of an expert diagnostic system for moving-coil loudspeakers. Special emphasis is placed on the defects resulting from loudspeaker nonlinearities. As a loudspeaker operates in the large signal domain, nonlinear distortions may arise and impair sound quality. Analysis of nonlinear responses can shed light on potential design faults of a loudspeaker. By exploiting this fact, this expert diagnostic system enables classification of design faults using a defect database alongside an intelligent fault inference module. Six types of defects are investigated in this paper. A large signal model based on electromechanical analogous circuits is employed for generating the defect database, through which a neural-fuzzy network is utilized for inferring the defect types. Numerical simulations and experimental investigations were undertaken for validating the loudspeaker diagnostic system.

  10. Adaptive tracking control for active suspension systems with non-ideal actuators

    NASA Astrophysics Data System (ADS)

    Pan, Huihui; Sun, Weichao; Jing, Xingjian; Gao, Huijun; Yao, Jianyong

    2017-07-01

    As a critical component of transportation vehicles, active suspension systems are instrumental in the improvement of ride comfort and maneuverability. However, practical active suspensions commonly suffer from parameter uncertainties (e.g., the variations of payload mass and suspension component parameters), external disturbances and especially the unknown non-ideal actuators (i.e., dead-zone and hysteresis nonlinearities), which always significantly deteriorate the control performance in practice. To overcome these issues, this paper synthesizes an adaptive tracking control strategy for vehicle suspension systems to achieve suspension performance improvements. The proposed control algorithm is formulated by developing a unified framework of non-ideal actuators rather than a separate way, which is a simple yet effective approach to remove the unexpected nonlinear effects. From the perspective of practical implementation, the advantages of the presented controller for active suspensions include that the assumptions on the measurable actuator outputs, the prior knowledge of nonlinear actuator parameters and the uncertain parameters within a known compact set are not required. Furthermore, the stability of the closed-loop suspension system is theoretically guaranteed by rigorous mathematical analysis. Finally, the effectiveness of the presented adaptive control scheme is confirmed using comparative numerical simulation validations.

  11. Developments of high- Tc superconducting current feeders for a large-scale superconducting coil system

    NASA Astrophysics Data System (ADS)

    Mito, T.; Maehata, K.; Mizokami, M.; Ishibashi, K.; Takeo, M.; Iwamoto, A.; Hirano, N.; Shintomi, T.; Kimura, K.; Sawamura, M.; Yamada, S.; Satoh, S.; Motojima, O.

    1998-10-01

    A large-scale superconducting coil system, which is an essential technology for a fusion reactor, requires large capacity and high performance current feeders from the power supplies at the room temperature to the superconducting coils at the operating temperature, which is usually liquid helium temperature at present. The superconducting current feeders are being considered as a promising application of a high temperature superconductor (HTS), which can satisfy the requirements of a large current capacity and a low heat in-leak, simultaneously. To study the feasibility of the HTS current feeders, a melt-textured YBCO bulk superconductor was selected as a candidate material because of its high current transport characteristics. The YBCO disk fabricated by quench and melt growth process was cut into a short sample with the cross section of 7 mm × 7 mm and the length of 40 mm and was mounted on the copper bars to perform the actual large current transport tests. The sample could be successfully excited up to 20 kA at 4.2 K and 10 kA at 77 K. These performance test results and the further R&D items for the HTS current feeders are discussed.

  12. Clinical implication of interface pressure for a new prosthetic suspension system

    PubMed Central

    2014-01-01

    Background Prosthesis suspension systems can alter the distribution of pressure within the prosthetic socket. This study evaluates a new suspension system for lower limb prostheses, and aims to compare the interface pressure and amputees’ satisfaction with the new system compared with a common prosthetic suspension system (pin/lock). Methods Ten transtibial amputees walked at a self-selected speed on a level ground with two different suspension systems, namely the pin/lock and HOLO system. The interface pressure was measured using the F-socket transducers at the proximal, middle and distal sites of residual limb. Furthermore, subjective feedback was logged to compare two systems. Results The pressure was significantly higher at the proximal and distal areas with the pin/lock suspension system during the swing phase of gait (P < 0.05). Subjective feedback also showed traction at the stump with the pin/lock system. There were no significant differences in the pressure applied to the mid-anterior and mid posterior stump for both suspension systems. However, the lateral and medial sides exhibited higher pressure with the new system during stance phase. Conclusions The intention of this study was to deepen understanding on the effect of suspension system on the load distribution over the residual limb. The new coupling system was proved compatible with the pin/lock system in terms of suspending the leg and amputee’s satisfaction. On the other hand, the HOLO system could distribute the pressure more uniformly over the residual limb. PMID:24981801

  13. Analysis of semi-active vehicle suspension system using airspring and MR damper

    NASA Astrophysics Data System (ADS)

    Tesfay, A. H.; Goel, V. K.

    2015-12-01

    With the new advancements in vibration control strategies and controllable actuator manufacturing, semi-active actuators and dampers are finding their way as an essential part of vibration isolators, particularly in vehicle suspension systems. This is attributed to the fact that in a semi-active system, the damping coefficients can be adjusted to improve ride comfort and road handling performances. The currently available semi-active damper technology uses MR fluid to control the damping characteristics of the suspension system. In addition to MR dampers, combining air springs in a semi-active suspension system leads to better handling and ride performance in vehicles. Furthermore, the use of air spring in semi-active suspension system helps to ease design of variable spring stiffness. This easy design opportunity leads to independent control of stiffness and ride height of the vehicle. This paper deals with the design and modelling of variable stiffness air spring for semi-active suspension system, modelling of semi-active suspension systems with variable stiffness and MR damper, and study their

  14. Performance analysis of a semiactive suspension system with particle swarm optimization and fuzzy logic control.

    PubMed

    Qazi, Abroon Jamal; de Silva, Clarence W; Khan, Afzal; Khan, Muhammad Tahir

    2014-01-01

    This paper uses a quarter model of an automobile having passive and semiactive suspension systems to develop a scheme for an optimal suspension controller. Semi-active suspension is preferred over passive and active suspensions with regard to optimum performance within the constraints of weight and operational cost. A fuzzy logic controller is incorporated into the semi-active suspension system. It is able to handle nonlinearities through the use of heuristic rules. Particle swarm optimization (PSO) is applied to determine the optimal gain parameters for the fuzzy logic controller, while maintaining within the normalized ranges of the controller inputs and output. The performance of resulting optimized system is compared with different systems that use various control algorithms, including a conventional passive system, choice options of feedback signals, and damping coefficient limits. Also, the optimized semi-active suspension system is evaluated for its performance in relation to variation in payload. Furthermore, the systems are compared with respect to the attributes of road handling and ride comfort. In all the simulation studies it is found that the optimized fuzzy logic controller surpasses the other types of control.

  15. Performance Analysis of a Semiactive Suspension System with Particle Swarm Optimization and Fuzzy Logic Control

    PubMed Central

    Qazi, Abroon Jamal; de Silva, Clarence W.

    2014-01-01

    This paper uses a quarter model of an automobile having passive and semiactive suspension systems to develop a scheme for an optimal suspension controller. Semi-active suspension is preferred over passive and active suspensions with regard to optimum performance within the constraints of weight and operational cost. A fuzzy logic controller is incorporated into the semi-active suspension system. It is able to handle nonlinearities through the use of heuristic rules. Particle swarm optimization (PSO) is applied to determine the optimal gain parameters for the fuzzy logic controller, while maintaining within the normalized ranges of the controller inputs and output. The performance of resulting optimized system is compared with different systems that use various control algorithms, including a conventional passive system, choice options of feedback signals, and damping coefficient limits. Also, the optimized semi-active suspension system is evaluated for its performance in relation to variation in payload. Furthermore, the systems are compared with respect to the attributes of road handling and ride comfort. In all the simulation studies it is found that the optimized fuzzy logic controller surpasses the other types of control. PMID:24574868

  16. Development of Non-destructive Evaluation System Using an HTS-SQUID Gradiometer with an External Pickup Coil

    NASA Astrophysics Data System (ADS)

    Kawano, J.; Kawauchi, S.; Ishikawa, F.; Tanabe, K.

    We are developing a new eddy-current non-destructive evaluation (NDE) system using a high-temperature superconducting quantum interference device (HTS-SQUID) gradiometer with the aim of applying it to power plants. Electric power facilities such as ducts and vessels are generally untransportable because of their size, and thus it is difficult to apply a conventional SQUID NDE system. The new NDE system employs an external Cu pickup coil which is supposed to be driven flexibly by a robot arm at room temperature and an HTS-SQUID chip which is placed in a magnetically shielded vessel. In the present research, we investigated the performance of an HTS-SQUID sensor connected with external pickup coils before mounting them to a robot arm. By varying the Cu coil conditions such as their sizes, the number of turns, and the diameter of wire, we qualitatively evaluated the frequency dependence of the effective area and the cutoff frequency.

  17. Development of an inductively-coupled MR coil system for imaging and spectroscopic analysis of an implantable bioartificial construct at 11.1T

    PubMed Central

    Volland, Nelly A.; Mareci, Thomas H.; Constantinidis, Ioannis; Simpson, Nicholas E.

    2010-01-01

    Developing a method to non-invasively monitor tissue engineered constructs is critical for the optimization of construct design and for assessing therapeutic efficacy. For this purpose, NMR is a powerful technique that can be used to obtain both images and spectroscopic data. But the inherent sensitivity of NMR limits the observation of a bioartificial construct with current NMR surface coil technology. In this study, we address this limitation through the development of an inductively-coupled, implantable coil system, demonstrate its use at high field (11.1T), and investigate the use of this coil system for monitoring a bioartificial construct in vitro and in vivo. The results establish that large gains in signal-to-noise can be obtained with this coil system over that obtainable with a surface coil. This coil system provides a means to quantitatively analyze the structure and function of implanted bioartificial organs. PMID:20373400

  18. Simplified Analytical Model of a Six-Degree-of-Freedom Large-Gap Magnetic Suspension System

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.

    1997-01-01

    A simplified analytical model of a six-degree-of-freedom large-gap magnetic suspension system is presented. The suspended element is a cylindrical permanent magnet that is magnetized in a direction which is perpendicular to its axis of symmetry. The actuators are air core electromagnets mounted in a planar array. The analytical model consists of an open-loop representation of the magnetic suspension system with electromagnet currents as inputs.

  19. Random vibrations of quadratic damping systems. [optimum damping analysis for automobile suspension system

    NASA Technical Reports Server (NTRS)

    Sireteanu, T.

    1974-01-01

    An oscillating system with quadratic damping subjected to white noise excitation is replaced by a nonlinear, statistically equivalent system for which the associated Fokker-Planck equation can be exactly solved. The mean square responses are calculated and the optimum damping coefficient is determined with respect to the minimum mean square acceleration criteria. An application of these results to the optimization of automobile suspension damping is given.

  20. Random vibrations of quadratic damping systems. [optimum damping analysis for automobile suspension system

    NASA Technical Reports Server (NTRS)

    Sireteanu, T.

    1974-01-01

    An oscillating system with quadratic damping subjected to white noise excitation is replaced by a nonlinear, statistically equivalent system for which the associated Fokker-Planck equation can be exactly solved. The mean square responses are calculated and the optimum damping coefficient is determined with respect to the minimum mean square acceleration criteria. An application of these results to the optimization of automobile suspension damping is given.

  1. Computer-based data acquisition system in the Large Coil Test Facility

    SciTech Connect

    Gould, S.S.; Layman, L.R.; Million, D.L.

    1983-01-01

    The utilization of computers for data acquisition and control is of paramount importance on large-scale fusion experiments because they feature the ability to acquire data from a large number of sensors at various sample rates and provide for flexible data interpretation, presentation, reduction, and analysis. In the Large Coil Test Facility (LCTF) a Digital Equipment Corporation (DEC) PDP-11/60 host computer with the DEC RSX-11M operating system coordinates the activities of five DEC LSI-11/23 front-end processors (FEPs) via direct memory access (DMA) communication links. This provides host control of scheduled data acquisition and FEP event-triggered data collection tasks. Four of the five FEPs have no operating system.

  2. Double pancake superconducting coil design for maximum magnetic energy storage in small scale SMES systems

    NASA Astrophysics Data System (ADS)

    Hekmati, Arsalan; Hekmati, Rasoul

    2016-12-01

    Electrical power quality and stability is an important issue nowadays and technology of Superconducting Magnetic Energy Storage systems, SMES, has brought real power storage capability to power systems. Therefore, optimum SMES design to achieve maximum energy with the least length of tape has been quite a matter of concern. This paper provides an approach to design optimization of solenoid and toroid types of SMES, ensuring maximum possible energy storage. The optimization process, based on Genetic Algorithm, calculates the operating current of superconducting tapes through intersection of a load line with the surface indicating the critical current variation versus the parallel and perpendicular components of magnetic flux density. FLUX3D simulations of SMES have been utilized for energy calculations. Through numerical analysis of obtained data, formulations have been obtained for the optimum dimensions of superconductor coil and maximum stored energy for a given length and cross sectional area of superconductor tape.

  3. An improved saddle coil for MR imaging in resistive magnet systems.

    PubMed

    Doornbos, J; Booijen, P E; Grimbergen, H A; Falke, T H

    1985-10-01

    The design of a two-turn radiofrequency coil for MR imaging at 0.15 T is presented. The use of well-isolated copper tube (instead of the usual wire) as conductor material resulted in an open, patient friendly construction. Furthermore, the Q value and signal-to-noise ratio of the tube-type coil were increased as compared to the corresponding values in the case of a geometrically similar wire-type coil.

  4. Independent wheel suspension system using thrust bearing constant velocity universal drive joints as suspension members to minimize wheel chamber

    SciTech Connect

    Krude, W.

    1986-12-30

    An independent wheel suspension system is described for a vehicle having an engine adapted to provide a driving torque, a chassis, vehicle support means for resiliently supporting the chassis for displacement relative to a driving surface, and a wheel assembly for each wheel having a vertical center plane through the center thereof and a wheel axis substantially perpendicular to the vertical center plane. The wheel assembly has a chamber angle relative to the vertical center plane adapted to undergo a change of chamber as the wheel assembly undergoes movement relative to the vertical center plane. The independent wheel suspension system comprises: differential means comprising a differential housing, a differential input at an engine end of the differential housing adapted to be coupled to the engine so as to receive the driving torque therefrom about a differential input axis. The differential housing has a pair of lateral sides on opposite sides of the differential input axis, each lateral side having a differential output axis therethrough. The differential means is adapted to redirect the driving torque from the differential input axis to the differential output axis and is supported by the vehicle support means to position the differential input axis substantially perpendicular to the wheel axis.

  5. Uniform magnetic fields and double-wrapped coil systems: improved techniques for the design of bioelectromagnetic experiments.

    PubMed

    Kirschvink, J L

    1992-01-01

    A common mistake in biomagnetic experimentation is the assumption that Helmholtz coils provide uniform magnetic fields; this is true only for a limited volume at their center. Substantial improvements on this design have been made during the past 140 years with systems of three, four, and five coils. Numerical comparisons of the field uniformity generated by these designs are made here, along with a table of construction details and recommendations for their use in experiments in which large volumes of uniform intensity magnetic exposures are needed. Double-wrapping, or systems of bifilar windings, can also help control for the non-magnetic effects of the electric coils used in many experiments. In this design, each coil is wrapped in parallel with two separate, adjacent strands of copper wire, rather than the single strand used normally. If currents are flowing in antiparallel directions, the magnetic fields generated by each strand will cancel and yield virtually no external magnetic field, whereas parallel currents will yield an external field. Both cases will produce similar non-magnetic effects of ohmic heating, and simple measures can reduce the small vibration and electric field differences. Control experiments can then be designed such that the only major difference between treated and untreated groups is the presence or absence of the magnetic field. Double-wrapped coils also facilitate the use of truly double-blind protocol, as the same apparatus can be used either for experimental or control groups.

  6. Design, simulation and evaluation of uniform magnetic field systems for head-free eye movement recordings with scleral search coils.

    PubMed

    Eibenberger, Karin; Eibenberger, Bernhard; Rucci, Michele

    2016-08-01

    The precise measurement of eye movements is important for investigating vision, oculomotor control and vestibular function. The magnetic scleral search coil technique is one of the most precise measurement techniques for recording eye movements with very high spatial (≈ 1 arcmin) and temporal (>kHz) resolution. The technique is based on measuring voltage induced in a search coil through a large magnetic field. This search coil is embedded in a contact lens worn by a human subject. The measured voltage is in direct relationship to the orientation of the eye in space. This requires a magnetic field with a high homogeneity in the center, since otherwise the field inhomogeneity would give the false impression of a rotation of the eye due to a translational movement of the head. To circumvent this problem, a bite bar typically restricts head movement to a minimum. However, the need often emerges to precisely record eye movements under natural viewing conditions. To this end, one needs a uniform magnetic field that is uniform over a large area. In this paper, we present the numerical and finite element simulations of the magnetic flux density of different coil geometries that could be used for search coil recordings. Based on the results, we built a 2.2 × 2.2 × 2.2 meter coil frame with a set of 3 × 4 coils to generate a 3D magnetic field and compared the measured flux density with our simulation results. In agreement with simulation results, the system yields a highly uniform field enabling high-resolution recordings of eye movements.

  7. Ride performance of a high speed rail vehicle using controlled semi active suspension system

    NASA Astrophysics Data System (ADS)

    Sharma, Sunil Kumar; Kumar, Anil

    2017-05-01

    The rail-wheel interaction in a rail vehicle running at high speed results in large amplitude vibration of carbody that deteriorates the ride comfort of travellers. The role of suspension system is crucial to provide an acceptable level of ride performance. In this context, an existing rail vehicle is modelled in vertical, pitch and roll motions of carbody and bogies. Additionally, nonlinear stiffness and damping parameters of passive suspension system are defined based on experimental data. In the secondary vertical suspension system, a magneto-rheological (MR) damper is included to improve the ride quality and comfort. The parameters of MR damper depend on the current, amplitude and frequency of excitations. At different running speeds, three semi-active suspension strategies with MR damper are analysed for periodic track irregularity and the resulting performance indices are juxtaposed with the nonlinear passive suspension system. The disturbance rejection and force tracking damper controller algorithms are applied to control the desired force of MR damper. This study reveals that the vertical vibrations of a vehicle can be reduced significantly by using the proposed semi-active suspension strategies. Moreover, it naturally results in improved ride quality and passenger’s comfort in comparison to the existing passive system.

  8. Optimization of damping in the passive automotive suspension system with using two quarter-car models

    NASA Astrophysics Data System (ADS)

    Lozia, Z.; Zdanowicz, P.

    2016-09-01

    The paper presents the optimization of damping in the passive suspension system of a motor vehicle moving rectilinearly with a constant speed on a road with rough surface of random irregularities, described according to the ISO classification. Two quarter-car 2DoF models, linear and non-linear, were used; in the latter, nonlinearities of spring characteristics of the suspension system and pneumatic tyres, sliding friction in the suspension system, and wheel lift-off were taken into account. The smoothing properties of vehicle tyres were represented in both models. The calculations were carried out for three roads of different quality, with simulating four vehicle speeds. Statistical measures of vertical vehicle body vibrations and of changes in the vertical tyre/road contact force were used as the criteria of system optimization and model comparison. The design suspension displacement limit was also taken into account. The optimum suspension damping coefficient was determined and the impact of undesirable sliding friction in the suspension system on the calculation results was estimated. The results obtained make it possible to evaluate the impact of the structure and complexity of the model used on the results of the optimization.

  9. Posttreatment PET-CT-confirmed intrahepatic radioembolization performed without coil embolization, by using the antireflux Surefire Infusion System.

    PubMed

    van den Hoven, Andor F; Prince, Jip F; Samim, Morsal; Arepally, Aravind; Zonnenberg, Bernard A; Zonneberg, Bernard A; Lam, Marnix G E H; van den Bosch, Maurice A A J

    2014-04-01

    Intra-arterial radioembolization with yttrium-90 microspheres is a safe and effective treatment option for patients with unresectable liver tumors. Pretreatment coil embolization of extrahepatic vessels is recommended to avoid extrahepatic deposition of radioactive microspheres. A novel infusion system with an expandable tip, the Surefire Infusion System (SIS), has recently been developed to minimize reflux. We report three cases of radioembolization with the use of the SIS. In all cases, yttrium-90 radioembolization was performed successfully without coil embolization of extrahepatic vessels. In all patients, positron emission tomography-computed tomography confirmed intrahepatic biodistribution of the microspheres in all targeted liver segments, and no extrahepatic deposition. With the use of the SIS, the need for coil embolization of extrahepatic vessels might be eliminated, and treatment may be extended to patients who were previously deemed unfit.

  10. Time response analysis in suspension system design of a high-speed car

    NASA Astrophysics Data System (ADS)

    Pagwiwoko, Cosmas Pandit

    2010-03-01

    A land speed record vehicle is designed to run on a flat surface like salt lake where the wheels are normally made from solid metal with a special suspension system. The suspension is designed to provide a stable platform to keep the wheel treads on tract, to insulate the car and the driver from the surface irregularities and to take part of good handling properties. The surface condition of the lake beds is basically flat without undulations but with inconsistent surface textures and ridges. Spring with nonlinear rate is used with the reason that the resistance builds up roughly proportional to the aerodynamic download for keeping the height more nearly constant. The objective of the work is to produce an efficient method for assisting the design of suspension system. At the initial step, the stiffness and the damping constants are determined based on RMS optimization by following the optimization strategy i.e. to minimize the absolute acceleration respect to the relative displacement of the suspension. Power bond graph technique is then used to model the nonlinearity of the components i.e. spring and dashpot of the suspension system. This technique also enables to incorporate the interactions of dynamic response of the vehicle's body with aerodynamic flow as a result of the base excitation of the ground to the wheels. The simulation is conducted on the platform of Simulink-MATLAB and the interactions amongst the components within the system are observed in time domain to evaluate the effectiveness of the suspension.

  11. Time response analysis in suspension system design of a high-speed car

    NASA Astrophysics Data System (ADS)

    Pagwiwoko, Cosmas Pandit

    2009-12-01

    A land speed record vehicle is designed to run on a flat surface like salt lake where the wheels are normally made from solid metal with a special suspension system. The suspension is designed to provide a stable platform to keep the wheel treads on tract, to insulate the car and the driver from the surface irregularities and to take part of good handling properties. The surface condition of the lake beds is basically flat without undulations but with inconsistent surface textures and ridges. Spring with nonlinear rate is used with the reason that the resistance builds up roughly proportional to the aerodynamic download for keeping the height more nearly constant. The objective of the work is to produce an efficient method for assisting the design of suspension system. At the initial step, the stiffness and the damping constants are determined based on RMS optimization by following the optimization strategy i.e. to minimize the absolute acceleration respect to the relative displacement of the suspension. Power bond graph technique is then used to model the nonlinearity of the components i.e. spring and dashpot of the suspension system. This technique also enables to incorporate the interactions of dynamic response of the vehicle's body with aerodynamic flow as a result of the base excitation of the ground to the wheels. The simulation is conducted on the platform of Simulink-MATLAB and the interactions amongst the components within the system are observed in time domain to evaluate the effectiveness of the suspension.

  12. A decoupled control approach for magnetic suspension systems using electromagnets mounted in a planar array

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.

    1993-01-01

    A decoupled control approach for a Large Gap Magnetic Suspension System (LGMSS) is presented. The control approach is developed for an LGMSS which provides five degree-of-freedom control of a cylindrical suspended element that contains a core composed of permanent magnet material. The suspended element is levitated above five electromagnets mounted in a planar array. Numerical results are obtained by using the parameters of the Large Angle Magnetic Suspension Test Fixture (LAMSTF) which is a small scale laboratory model LGMSS.

  13. Implementation and operation of VAX-based data acquisition system for the large coil task

    SciTech Connect

    Baylor, L.R.; Blair, E.T.; Greenwood, D.E.; Munro, J.K.

    1985-01-01

    The VAX-based data acquisition system for the International Fusion Superconducting Magnet Test Facility (IFSMTF) at Oak Ridge National Laboratory (ORNL) is a second generation system that evolved from a PDP-11/60-based system used in the two-coil test and facility shakedown. The VAX 11/780 processor has been interfaced through a CAMAC fiber-optic byte serial highway to five existing LSI-11/23 frontend processors through dataway access port (DAP) modules. The VAX CAMAC interface has permitted the addition of analog input channels for the refrigeration system and analog and digital outputs to drive display devices. Software utilities are provided to operate the data acquisition hardware, maintain data base files, and display data. Graphical display of data is accomplished through the use of VAX IDL (Interactive Data Language), which provides device-independent data presentation. Output from IDL is available for Tektronix displays and has been extended to generate TKF and Versaplot graphics metafiles for hardcopy output to Versatec printer/plotters. In addition, a Sension display system is available for graphical display of real-time data in the form of strip chart and tabular displays. This paper describes the hardware and software design of the system and the operation of the system during the full-array testing sequence.

  14. Analysis of relay based valley coil system of K-130 Cyclotron and an approach to computer controlled system

    NASA Astrophysics Data System (ADS)

    Shoor, B.

    2016-09-01

    To overcome the first harmonic field imperfection in sector focused cyclotron, a set of coils placed in valleys are used to produce an opposite first harmonic effect. Usually, at the time of beam tuning the phase of the first harmonic is varied using a relay system. It can be shown analytically that magnitude of it changes simultaneously, when phase is changed. This is not desirable at the time of beam tuning. Moreover phase changes in long steps, which hampers accuracy of beam tuning. To overcome this, a computer controlled system is suggested where amplitude remains constant at the time of phase change. Moreover, phase can be changed continuously which gives better tuning accuracy.

  15. Lateral Vibration Attenuation by the Dynamic Adjustment of Bias Currents in Magnetic Suspension System

    NASA Astrophysics Data System (ADS)

    Mizuno, Takeshi; Takasaki, Masaya; Ishino, Yuji

    2016-09-01

    Switching stiffness control is applied to attenuate vibration in the lateral directions in an active magnetic suspension system with electromagnets operated in differential mode. The magnetic suspension system using the attractive force between magnetized bodies is inherently unstable in the normal direction so that feedback control is necessary to achieve stable suspension. In contrast, it can be stable in the lateral directions due to the edge effects in the magnetic circuits. In several applications, such passive suspension is used in combination with the active one to reduce cost and space. However, damping in the lateral directions is generally small. As a result, induced vibrations in these directions are hardly attenuated. To suppress such vibration without any additional actuator (electromagnet), switching stiffness control is applied to an magnetic suspension system operated in the differential mode. The stiffness in the lateral direction is adjusted by varying the bias currents of an opposed pair of electromagnets located in the normal direction simultaneously according to the motion of the suspended object. When the varied bias currents are adjusted for the additive normal forces cancel each other, such control does not affect the suspension in the normal direction. The effectiveness of the proposed control methods is confirmed experimentally.

  16. 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.

  17. Coiled tubing: Early warning system to detect flaws in flat sheet prior to rolling and welding

    SciTech Connect

    Edens, C.W. )

    1994-05-01

    Through experimentation and dynamic evaluation of skelp at a coiled tubing mill, the use of leakage flux solid state sensing devices shows clearly that the requirement for nondestructively testing skelp can be met. As coiled tubing for drilling purposes gains wider usage, its skelp can take advantage of upstream inspection prior to forming the tubes. A reliable coiled tubing product is one in which every aspect of its manufacturing was considered, from raw material through final inspection. In no other way can the concept of total quality management be satisfied providing reliability of product use. A guarantee of fitness for purpose falls directly on the coiled tubing manufacturer. Purveyors of jointed electronic resistance weld tubulars may also take advantage of this inspection method. The American Petroleum Institute (API) has recently established a committee to study and formulate recommended practices for coiled tubing operations.

  18. EMAT weld inspection and weld machine diagnostic system for continuous coil processing lines

    NASA Astrophysics Data System (ADS)

    Latham, Wayne M.; MacLauchlan, Daniel T.; Geier, Dan P.; Lang, Dennis D.

    1996-11-01

    Weld breaks of steel coil during cold rolling and continuous pickling operations are a significant source of lost productivity and product yield. Babcock and Wilcox Innerspec Technologies has developed a weld process control system which monitors the key variables of the welding process and determines the quality of the welds generated by flash butt welding equipment. This system is known as the Temate 2000 Automated Flash Butt Weld Inspection and Weld Machine Diagnostic System. The Temate 2000 system utilizes electro- magnetic acoustic transducer (EMAT) technology as the basis for performing on-line, real-time, nondestructive weld quality evaluation. This technique accurately detects voids, laps, misalignment and over/under trim conditions in the weld. Results of the EMAT weld inspection are immediately presented to the weld machine operator for disposition. Welding process variables such as voltage, current, platen movements and upset pressures are monitored and collected with the high speed data acquisition system. This data is processed and presented in real-time display to indicate useful welding process information such as platen crabbing, upset force, peak upset current, and many others. Alarming for each variable is provided and allows detailed maintenance reports and summary information to be generated. All weld quality and process parameter data are stored, traceable to each unique weld, and available for post process evaluation. Installation of the Temate 2000 system in a major flat rolled steel mill has contributed to near elimination of weld breakage and increased productivity at this facility.

  19. Further developments relating to the NASA Langley Research Center 13-inch magnetic suspension and balance system

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.

    1991-01-01

    A few specific developments that were undertaken recently to the magnetic suspension and balance system (MSBS) are detailed. The improvements are as follows: modifications to the digital control system to accommodate a modified position sensing system; development of pressure telemetry systems; and revisions to the wind tunnel test section.

  20. Identification of the technical state of suspension elements in railway systems

    NASA Astrophysics Data System (ADS)

    Martinod, Ronald Mauricio; René Betancur, German; Francisco Castañeda Heredia, Leonel

    2012-07-01

    The running safety and passenger comfort levels in a vehicle are tightly related to the technical state of the suspension elements. The technical state of the suspension depends of the service life time as its components become old and wear out. In this paper, a study on the dynamic behaviour of a railway vehicle is established in relation to the damping elements in one of its suspension stages. An experimental measurement model is developed, obtaining a set of useful signals for the identification of the dynamic parameters of the vehicle and developing a test through the application of the operational modal analysis technique, using least-squares complex exponential method as a basis to validate the numerical model of the multi-body system. Then, the study focuses on developing numerical simulations for the identification of the technical state of the dampers by the registration of dynamic variables under commercial service conditions and on estimating the state of the suspension elements.

  1. Optical position measurement for a large gap magnetic suspension system: Design and performance analysis

    NASA Technical Reports Server (NTRS)

    Welch, Sharon S.; Clemmons, James I., Jr.; Shelton, Kevin J.; Duncan, Walter C.

    1994-01-01

    An optical measurement system (OMS) has been designed and tested for a large gap magnetic suspension system (LGMSS). The LGMSS will be used to study control laws for magnetic suspension systems for vibration isolation and pointing applications. The LGMSS features six degrees of freedom and consists of a planar array of electromagnets that levitate and position a cylindrical element containing a permanent magnet core. The OMS provides information on the location and orientation of the element to the LGMSS control system to stabilize suspension. The hardware design of this optical sensing system and the tracking algorithms are presented. The results of analyses and experiments are presented that define the accuracy limits of the optical sensing system and that quantify the errors in position estimation.

  2. Equilibrium field coil concepts for INTOR

    SciTech Connect

    Strickler, D.J.; Peng, Y.K.M.; Brown, T.G.

    1981-08-01

    Methods are presented for reducing ampere-turn requirements in the EF coil system. It is shown that coil currents in an EF coil system external to the toroidal field coils can be substantially reduced by relaxing the triangularity of a D-shaped plasma. Further reductions are realized through a hybrid EF coil system using both internal and external coils. Equilibrium field coils for a poloidally asymmetric, single-null INTOR configuration are presented. It is shown that the shape of field lines in the plasma scrapeoff region and divertor channel improves as triangularity is reduced, but it does so at the possible expense of achievable stable beta values.

  3. Electromagnetic thermotherapy for deep organ ablation by using a needle array under a synchronized-coil system.

    PubMed

    Huang, Sheng-Chieh; Kang, Jui-Wen; Tsai, Hung-Wen; Shan, Yan-Shen; Lin, Xi-Zhang; Lee, Gwo-Bin

    2014-11-01

    Thermal ablation by using electromagnetic thermotherapy (EMT) has been a promising cancer modality in recent years. It has relatively few side effects and has therefore been extensively investigated for a variety of medical applications in internal medicine and surgery. The EMT system applies a high-frequency alternating electromagnetic field to heat up the needles which are inserted into the target tumor to cause tumor ablation. In this study, a new synchronized-coil EMT system was demonstrated, which was equipped with two synchronized coils and magnetic field generators to provide a long-range, penetrated electromagnetic field to effectively heat up the needles. The heating effect of the needles at the center of the two coils was first explored. The newly designed two-section needle array combined with the synchronized-coil EMT system was thus demonstrated in the in vitro and in vivo animal experiments. Experimental data showed that the developed system is promising for minimally invasive surgery since it might provide superior performance for thermotherapy in cancer treatment.

  4. Analyzing the uniformity of the generated magnetic field by a practical one-dimensional Helmholtz coils system.

    PubMed

    Beiranvand, R

    2013-07-01

    Using the Helmholtz coils system is one of the most suitable approaches which have been introduced for generating uniform magnetic fields. In this paper, uniformity of the generated magnetic field by a practical one-dimensional (1D) Helmholtz coils system has been analyzed, mathematically. For this purpose, relationships between the magnetic field uniformity and different practical unavoidable mismatches have been extracted. The theoretical analysis clearly demonstrates the effect of assembly misalignments and manufacturing mismatches on the magnetic field achieved by a practical 1D Helmholtz coils system. The given analyses have been confirmed by the experimental results which are in good agreement with the calculated values. This analysis and the experimental results illustrate that to achieve a very high uniform magnetic field, practical assembly misalignments, and manufacturing mismatches must be as small as possible, and the background magnetic field distortion must be avoided, too. The results of this work are important in the design of instruments and systems where Helmholtz coils are used.

  5. Coil spring venting arrangement

    DOEpatents

    McCugh, R.M.

    1975-10-21

    A simple venting device for trapped gas pockets in hydraulic systems is inserted through a small access passages, operated remotely, and removed completely. The device comprises a small diameter, closely wound coil spring which is pushed through a guide temporarily inserted in the access passage. The guide has a central passageway which directs the coil spring radially upward into the pocket, so that, with the guide properly positioned for depth and properly oriented, the coil spring can be pushed up into the top of the pocket to vent it. By positioning a seal around the free end of the guide, the spring and guide are removed and the passage is sealed.

  6. Effects of the Truck Suspension System on Animal Welfare, Carcass and Meat Quality Traits in Pigs

    PubMed Central

    Dalla Costa, Filipe Antônio; Lopes, Letícia S.; Dalla Costa, Osmar Antônio

    2017-01-01

    Simple Summary Transportation is a complex stressor in which animals are exposed to a series negatively stimuli, such as vibration, new environmental conditions, variation in temperature and humidity, social mixing, noises among other poor factors, which can result in welfare problems and economic losses such as increased skin lesions, poorer pork quality traits. Transport stress may be reduced through a vehicle suspension system that provides a much smoother ride during transport, and consequently is less aversive to pigs. However, air suspension systems are more expensive and have bigger maintenance costs. This increase in transportation cost must be supported by the benefits from improvements in quality of freight transport; otherwise, the truckers will be paying unnecessarily for a similar or equivalent ride quality. Thus, finishing pigs were assessed after transport to slaughter by the same two double-decked trucks using two types of commercial vehicle suspension, leaf-spring and air suspension, to compare effects on blood cortisol and lactate at exsanguination, behaviour during lairage, and carcass (skin lesions) and pork quality traits. The use of leaf-spring suspension system negatively affects the welfare of pigs due to the increased carcass damage and resulted in poorer pork quality traits. Abstract The objective of this study was to assess the effects of two types of commercial suspension (leaf-spring (LS) vs. air suspension (AS)) installed on two similar double-decked trucks on blood cortisol and lactate concentration, lairage behavior, carcass skin lesions and pork quality traits of 120 crossbred pigs. The suspension type neither influenced pig behaviour in lairage nor blood cortisol and lactate concentrations (p > 0.10). However, when compared with the AS suspension system, the use of LS increased the number of skin lesions in the back and thigh (p = 0.03 and p = 0.01, respectively) and produced thigh with lower pHu (p < 0.001) and yellower colour

  7. An isotropic suspension system for a biaxial accelerometer using electroplated thick metal with a HAR SU-8 mold

    NASA Astrophysics Data System (ADS)

    Lee, Jin Seung; Lee, Seung S.

    2008-02-01

    In this paper, a novel approach is developed to design an isotropic suspension system using thick metal freestanding micro-structures combining bulk micro-machining with electroplating based on a HAR SU-8 mold. An omega-shape isotropic suspension system composed of circular curved beams that have free switching of imaginary boundary conditions is proposed. This novel isotropic suspension design is not affected by geometric dimensional parameters and always achieves matching stiffness along the principle axes of elasticity. Using the finite element method, the isotropic suspension system was compared with an S-shaped meandering suspension system. In order to realize the suggested isotropic suspension system, a cost-effective fabrication process using electroplating with the SU-8 mold was developed to avoid expensive equipment and materials such as deep reactive-ion etching (DRIE) or a silicon-on-insulator (SOI) wafer. The fabricated isotropic suspension system was verified by electromagnetic actuation experiments. Finally, a biaxial accelerometer with isotropic suspension system was realized and tested using a vibration generator system. The proposed isotropic suspension system and the modified surface micro-machining technique based on electroplating with an SU-8 mold can contribute towards minimizing the system size, simplifying the system configuration, reducing the system price of and facilitating mass production of various types of low-cost sensors and actuators.

  8. A semi-active control suspension system for railway vehicles with magnetorheological fluid dampers

    NASA Astrophysics Data System (ADS)

    Wei, Xiukun; Zhu, Ming; Jia, Limin

    2016-07-01

    The high-speed train has achieved great progress in the last decades. It is one of the most important modes of transportation between cities. With the rapid development of the high-speed train, its safety issue is paid much more attention than ever before. To improve the stability of the vehicle with high speed, extra dampers (i.e. anti-hunting damper) are used in the traditional bogies with passive suspension system. However, the curving performance of the vehicle is undermined due to the extra lateral force generated by the dampers. The active suspension systems proposed in the last decades attempt to solve the vehicle steering issue. However, the active suspension systems need extra actuators driven by electrical power or hydraulic power. There are some implementation and even safety issues which are not easy to be overcome. In this paper, an innovative semi-active controlled lateral suspension system for railway vehicles is proposed. Four magnetorheological fluid dampers are fixed to the primary suspension system of each bogie. They are controlled by online controllers for enhancing the running stability on the straight track line on the one hand and further improving the curving performance by controlling the damper force on the other hand. Two control strategies are proposed in the light of the pure rolling concept. The effectiveness of the proposed strategies is demonstrated by SIMPACK and Matlab co-simulation for a full railway vehicle with two conventional bogies.

  9. Borehole induction coil transmitter

    DOEpatents

    Holladay, Gale; Wilt, Michael J.

    2002-01-01

    A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

  10. A compact spin-exchange optical pumping system for 3He polarization based on a solenoid coil, a VBG laser diode, and a cosine theta RF coil

    NASA Astrophysics Data System (ADS)

    Lee, Sungman; Kim, Jongyul; Moon, Myung Kook; Lee, Kye Hong; Lee, Seung Wook; Ino, Takashi; Skoy, Vadim R.; Lee, Manwoo; Kim, Guinyun

    2013-02-01

    For use as a neutron spin polarizer or analyzer in the neutron beam lines of the HANARO (High-flux Advanced Neutron Application ReactOr) nuclear research reactor, a 3He polarizer was designed based on both a compact solenoid coil and a VBG (volume Bragg grating) diode laser with a narrow spectral linewidth of 25 GHz. The nuclear magnetic resonance (NMR) signal was measured and analyzed using both a built-in cosine radio-frequency (RF) coil and a pick-up coil. Using a neutron transmission measurement, we estimated the polarization ratio of the 3He cell as 18% for an optical pumping time of 8 hours.

  11. 78 FR 58376 - Home System Group, Order of Suspension of Trading

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Home System Group, Order of Suspension of Trading September 19, 2013. It appears to the Securities... securities of Home System Group because Home System Group has not filed any periodic reports for any...

  12. Computer program for investigating effects of nonlinear suspension-system elastic properties on parachute inflation loads and motions

    NASA Technical Reports Server (NTRS)

    Poole, L. R.

    1972-01-01

    A computer program is presented by which the effects of nonlinear suspension-system elastic characteristics on parachute inflation loads and motions can be investigated. A mathematical elastic model of suspension-system geometry is coupled to the planar equations of motion of a general vehicle and canopy. Canopy geometry and aerodynamic drag characteristics and suspension-system elastic properties are tabular inputs. The equations of motion are numerically integrated by use of an equivalent fifth-order Runge-Kutta technique.

  13. H ∞ robust control of semi-active Macpherson suspension system: new applied design

    NASA Astrophysics Data System (ADS)

    Saber Fallah, Mohammad; Bhat, Rama; Xie, Wen-Fang

    2010-03-01

    In this paper, the performance of a robust control scheme for a Macpherson suspension system is investigated using new dynamic and kinematic models. While the new dynamic model incorporates the kinematics of the suspension in order to have a superior description of the plant dynamics, the three-dimensional kinematic model is used to evaluate the wheel motion subject to controlled force variation. A new definition of the measurement of the wheel-road contact is proposed based on the real function of the control arm. In addition, it is recommended to integrate the vertical displacement of the chassis in the formulation of the control design in order to improve wheel motions. It is shown that the robust semi-active suspension system has superior performance compared with those of a modified skyhook controller system and a passive system.

  14. Vibrational response of a moving suspension-slider loading system exciting a rotating flexible disk

    NASA Astrophysics Data System (ADS)

    Pei, Yong-Chen; Tan, Qing-Chang; Yang, Xin; Chatwin, Chris

    2012-07-01

    To investigate the vibrational response of the magnetic read/write head in hard disk drives this paper models a rotating flexible disk excited by a moving suspension-slider system which is considered to be a mass-dashpot-spring loading system, with the initial unstressed transverse runout integrated into the rotating disk dynamic model. The slider motion on the disk surface is driven by the suspension rotating at a constant speed. By subtracting the steady-state deflection component from the instantaneous deflection response of the rotating disk system, the relative vibration transverse deflection of the slider caused by the motion of the suspension-slider loading system is obtained. The effects of the slider initial and final positions, speed of movement, the disk rotational speed, and the disk mode of the initial transverse runout on the maximum amplitude of the relative vibration deflection are analyzed.

  15. Butt weld inspection and weld machine diagnostic system for continuous coil processing lines

    SciTech Connect

    Lang, D.D.; Geier, D.; Shultz, B.L.

    1995-07-01

    Weld breaks of steel coil during cold rolling and continuous pickling operations are a significant source of lost productivity and product yield. Babcock and Wilcox Innerspec Technologies has developed and installed a weld process control system which monitors the key variables of the welding process and determines the quality of welds generated by flash-butt welding equipment. The TEMATE 2000 System utilizes Electro-Magnetic Acoustic Transducer (EMAT) technology as the basis for performing on-line, real-time, nondestructive weld quality evaluation. This technique accurately detects voids, laps, misalignment and over/under trim conditions in the weld. Results of the EMAT weld inspection are immediately presented to the weld machine operator for disposition. All weld quality and process parameter data are stored, traceable to each unique weld, and available for post process evaluation. Installation of the TEMATE 2000 system in a major flat rolled steel mill has contributed to near elimination of weld breakage and increased productivity at this facility.

  16. Adaptive Super-Twisting Observer for Estimation of Random Road Excitation Profile in Automotive Suspension Systems

    PubMed Central

    Rath, J. J.; Veluvolu, K. C.; Defoort, M.

    2014-01-01

    The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive supertwisting observer for state and unknown road profile estimation. Under Lipschitz conditions for the nonlinear functions, the convergence of the estimation error is proven. Simulation results with Ford Fiesta MK2 demonstrate the effectiveness of the proposed observer for state and unknown input estimation for nonlinear active suspension system. PMID:24683321

  17. Adaptive super-twisting observer for estimation of random road excitation profile in automotive suspension systems.

    PubMed

    Rath, J J; Veluvolu, K C; Defoort, M

    2014-01-01

    The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive supertwisting observer for state and unknown road profile estimation. Under Lipschitz conditions for the nonlinear functions, the convergence of the estimation error is proven. Simulation results with Ford Fiesta MK2 demonstrate the effectiveness of the proposed observer for state and unknown input estimation for nonlinear active suspension system.

  18. Single-molecule observation of helix staggering, sliding, and coiled coil misfolding

    PubMed Central

    Xi, Zhiqun; Gao, Ying; Sirinakis, George; Guo, Honglian; Zhang, Yongli

    2012-01-01

    The biological functions of coiled coils generally depend on efficient folding and perfect pairing of their α-helices. Dynamic changes in the helical registry that lead to staggered helices have only been proposed for a few special systems and not found in generic coiled coils. Here, we report our observations of multiple staggered helical structures of two canonical coiled coils. The partially folded structures are formed predominantly by coiled coil misfolding and occasionally by helix sliding. Using high-resolution optical tweezers, we characterized their energies and transition kinetics at a single-molecule level. The staggered states occur less than 2% of the time and about 0.1% of the time at zero force. We conclude that dynamic changes in helical registry may be a general property of coiled coils. Our findings should have broad and unique implications in functions and dysfunctions of proteins containing coiled coils. PMID:22451899

  19. Thermoeconomic Optimization of a Combined Heating and Humidification Coil for HVAC Systems

    NASA Astrophysics Data System (ADS)

    Teodoros, Liliana; Andresen, Bjarne

    2016-07-01

    The total cost of ownership is calculated for a combined heating and humidification coil of an air-handling unit taking into account investment and operation costs simultaneously. This total cost represents the optimization function for which the minimum is sought. The parameters for the cost dependencies are the physical dimensions of the coil: length, width and height. The term "coil" is used generically since in this setup it generates heating as well as humidification in a single unit. The first part of the paper deals with the constructive optimization and finds the relationship between the dimensions for a minimum cost. The second part of the paper takes the results of the constructive optimization further and, based on the data derived in our previous papers, analyzes the minimum total cost for the humidification coil while balancing the amount of water used to humidify the air and modify its temperature.

  20. Simple and efficient plastid transformation system for the liverwort Marchantia polymorpha L. suspension-culture cells.

    PubMed

    Chiyoda, Shota; Linley, Philip J; Yamato, Katsuyuki T; Fukuzawa, Hideya; Yokota, Akiho; Kohchi, Takayuki

    2007-02-01

    We have established a simple and efficient plastid transformation system for liverwort, Marchantia polymorpha L., suspension-culture cells, which are homogenous, chloroplast-rich and rapidly growing. Plasmid pCS31 was constructed to integrate an aadA expression cassette for spectinomycin-resistance into the trnI-trnA intergenic region of the liverwort plastid DNA by homologous recombination. Liverwort suspension-culture cells were bombarded with pCS31-coated gold projectiles and selected on a medium containing spectinomycin. Plastid transformants were reproducibly isolated from the obtained spectinomycin-resistant calli. Selection on a sucrose-free medium greatly improved the efficiency of selection of plastid transformants. Homoplasmic plastid transformant lines were established by successive subculturing for 14 weeks or longer on the spectinomycin-containing medium. The plastid transformation system of liverwort suspension-culture cells should facilitate the investigation of the fundamental genetic systems of plastid DNA, such as replication.

  1. Pressure-Based Liquid Feed System for Suspension Plasma Spray Coatings

    NASA Astrophysics Data System (ADS)

    Cotler, Elliot M.; Chen, Dianying; Molz, Ronald J.

    2011-06-01

    Thermal spraying with liquid-based feedstocks demonstrated a potential to produce coatings with new and enhanced characteristics. A liquid delivery system prototype was developed and tested in this study. The feeder is based on the 5MPE platform and uses a pressure setup to optimally inject and atomize liquid feedstock into a plasma plume. A novel self-cleaning apparatus is incorporated into the system to greatly reduce problems associated with clogging and agglomeration of liquid suspensions. This approach also allows the liquid feedstock line to the gun to remain charged for quick on-off operation. Experiments on aqueous and ethanol-based suspensions of titania, alumina, and YSZ were performed through this liquid delivery system using a 9MB plasma gun. Coatings with ultrafine splat microstructures were obtained by plasma spraying of those suspensions. Phase composition and microstructure of the as-sprayed coatings were investigated.

  2. Robust finite-time tracking control for nonlinear suspension systems via disturbance compensation

    NASA Astrophysics Data System (ADS)

    Pan, Huihui; Jing, Xingjian; Sun, Weichao

    2017-05-01

    This paper focuses on the finite-time tracking control with external disturbance for active suspension systems. In order to compensate unknown disturbance efficiently, a disturbance compensator with finite-time convergence property is studied. By analyzing the discontinuous phenomenon of classical disturbance compensation techniques, this study presents a simple approach to construct a continuous compensator satisfying the finite-time disturbance rejection performance. According to the finite-time separation principle, the design procedures of the nominal controller for the suspension system without disturbance and the disturbance compensator can be implemented in a completely independent manner. Therefore, the overall control law for the closed-loop system is continuous, which offers some distinct advantages over the existing discontinuous ones. From the perspective of practical implementation, the continuous controller can avoid effectively the unexpected chattering in active suspension control. Comparative experimental results are presented and discussed to illustrate the advantage and effectiveness of the proposed control strategy.

  3. Application of metallic nanoparticle suspensions in advanced cooling systems

    SciTech Connect

    Lee, S.; Choi, S.U.S.

    1996-12-31

    In the development of energy-efficient heat transfer fluids that are required in many cooling applications, low thermal conductivity is a primary limitation. However, it is well known that at room temperature, metals in solid form have orders-of-magnitude higher thermal conductivities than those of fluids. Therefore, the thermal conductivities of fluids that contain suspended solid metallic particles are expected to be significantly enhanced over those of conventional heat transfer fluids. In fact, numerous theoretical and experimental studies of the effective thermal conductivity of dispersions that contain solid particles have been conducted since Maxwell`s theoretical was published more than 100 years ago. However, all of the studies on thermal conductivity of suspensions have been confined to millimeter- or micrometer-sized particles.

  4. Formation and stabilisation of triclosan colloidal suspensions using supersaturated systems.

    PubMed

    Raghavan, S L; Schuessel, K; Davis, A; Hadgraft, J

    2003-08-11

    The aim of this paper is to prepare and stabilise, in situ, colloidal microsuspensions of triclosan using the polymer, hydroxypropyl methylcellulose (HPMC). The suspensions were prepared from supersaturated solutions of triclosan. The cosolvent technique was used to create supersaturation. Propylene glycol and water were used as the cosolvents. The triclosan particles had a large needle-shaped morphology, when grown in the absence of the polymer. Moreover, the particles grew rapidly to sizes greater than 5 micrometer over a period of 7h. When HPMC was added, the particle sizes were in the range 90-250 nm depending on the amount of polymer present in the solutions. The stability of the solutions was evaluated over a period of 40 days during which the particle sizes did not vary. The results were consistent with the mechanism proposed by Raghavan et al. [Int. J. Pharm. 212 (2001b) 213].

  5. An Optimized Air-Core Coil Sensor with a Magnetic Flux Compensation Structure Suitable to the Helicopter TEM System

    PubMed Central

    Chen, Chen; Liu, Fei; Lin, Jun; Zhu, Kaiguang; Wang, Yanzhang

    2016-01-01

    The air-core coil sensor (ACS) is widely used as a transducer to measure the variation in magnetic fields of a helicopter transient electromagnetic (TEM) system. A high periodic emitting current induces the magnetic field signal of the underground medium. However, such current also generates a high primary field signal that can affect the received signal of the ACS and even damage the receiver. To increase the dynamic range of the received signal and to protect the receiver when emitting current rises/falls, the combination of ACS with magnetic flux compensation structure (bucking coil) is necessary. Moreover, the optimized ACS, which is composed of an air-core coil and a differential pre-amplifier circuit, must be investigated to meet the requirements of the helicopter TEM system suited to rapid surveying for shallow buried metal mine in rough topography. Accordingly, two ACSs are fabricated in this study, and their performance is verified and compared inside a magnetic shielding room. Using the designed ACSs, field experiments are conducted in Baoqing County. The field experimental data show that the primary field response can be compensated when the bucking coil is placed at an appropriate point in the range of allowed shift distance beyond the center of the transmitting coil and that the damage to the receiver induced by the over-statured signal can be solved. In conclusion, a more suitable ACS is adopted and is shown to have better performance, with a mass of 2.5 kg, resultant effective area of 11.6 m2 (i.e., diameter of 0.496 m), 3 dB bandwidth of 66 kHz, signal-to-noise ratio of 4 (i.e., varying magnetic field strength of 0.2 nT/s), and normalized equivalent input noise of 3.62 nV/m2. PMID:27077862

  6. An Optimized Air-Core Coil Sensor with a Magnetic Flux Compensation Structure Suitable to the Helicopter TEM System.

    PubMed

    Chen, Chen; Liu, Fei; Lin, Jun; Zhu, Kaiguang; Wang, Yanzhang

    2016-04-12

    The air-core coil sensor (ACS) is widely used as a transducer to measure the variation in magnetic fields of a helicopter transient electromagnetic (TEM) system. A high periodic emitting current induces the magnetic field signal of the underground medium. However, such current also generates a high primary field signal that can affect the received signal of the ACS and even damage the receiver. To increase the dynamic range of the received signal and to protect the receiver when emitting current rises/falls, the combination of ACS with magnetic flux compensation structure (bucking coil) is necessary. Moreover, the optimized ACS, which is composed of an air-core coil and a differential pre-amplifier circuit, must be investigated to meet the requirements of the helicopter TEM system suited to rapid surveying for shallow buried metal mine in rough topography. Accordingly, two ACSs are fabricated in this study, and their performance is verified and compared inside a magnetic shielding room. Using the designed ACSs, field experiments are conducted in Baoqing County. The field experimental data show that the primary field response can be compensated when the bucking coil is placed at an appropriate point in the range of allowed shift distance beyond the center of the transmitting coil and that the damage to the receiver induced by the over-statured signal can be solved. In conclusion, a more suitable ACS is adopted and is shown to have better performance, with a mass of 2.5 kg, resultant effective area of 11.6 m² (i.e., diameter of 0.496 m), 3 dB bandwidth of 66 kHz, signal-to-noise ratio of 4 (i.e., varying magnetic field strength of 0.2 nT/s), and normalized equivalent input noise of 3.62 nV/m².

  7. Linear Rogowski coil.

    PubMed

    Nassisi, V; Delle Side, D

    2017-02-01

    Nowadays, the employment and development of fast current pulses require sophisticated systems to perform measurements. Rogowski coils are used to diagnose cylindrical shaped beams; therefore, they are designed and built with a toroidal structure. Recently, to perform experiments of radiofrequency biophysical stresses, flat transmission lines have been developed. Therefore, in this work we developed a linear Rogowski coil to detect current pulses inside flat conductors. The system is first approached by means of transmission line theory. We found that, if the pulse width to be diagnosed is comparable with the propagation time of the signal in the detector, it is necessary to impose a uniform current as input pulse, or to use short coils. We further analysed the effect of the resistance of the coil and the influence of its magnetic properties. As a result, the device we developed is able to record pulses lasting for some hundreds of nanoseconds, depending on the inductance, load impedance, and resistance of the coil. Furthermore, its response is characterized by a sub-nanosecond rise time (∼100 ps). The attenuation coefficient depends mainly on the turn number of the coil, while the fidelity of the response depends both on the magnetic core characteristics and on the current distribution along the plane conductors.

  8. Linear Rogowski coil

    NASA Astrophysics Data System (ADS)

    Nassisi, V.; Delle Side, D.

    2017-02-01

    Nowadays, the employment and development of fast current pulses require sophisticated systems to perform measurements. Rogowski coils are used to diagnose cylindrical shaped beams; therefore, they are designed and built with a toroidal structure. Recently, to perform experiments of radiofrequency biophysical stresses, flat transmission lines have been developed. Therefore, in this work we developed a linear Rogowski coil to detect current pulses inside flat conductors. The system is first approached by means of transmission line theory. We found that, if the pulse width to be diagnosed is comparable with the propagation time of the signal in the detector, it is necessary to impose a uniform current as input pulse, or to use short coils. We further analysed the effect of the resistance of the coil and the influence of its magnetic properties. As a result, the device we developed is able to record pulses lasting for some hundreds of nanoseconds, depending on the inductance, load impedance, and resistance of the coil. Furthermore, its response is characterized by a sub-nanosecond rise time (˜100 ps). The attenuation coefficient depends mainly on the turn number of the coil, while the fidelity of the response depends both on the magnetic core characteristics and on the current distribution along the plane conductors.

  9. Design of the Annular Suspension and Pointing System (ASPS) (including design addendum)

    NASA Technical Reports Server (NTRS)

    Cunningham, D.; Gismondi, T.; Hamilton, B.; Kendig, J.; Kiedrowski, J.; Vroman, A.; Wilson, G.

    1980-01-01

    The Annular Suspension and Pointing System is an experiment pointing mount designed for extremely precise 3 axis orientation of shuttle experiments. It utilizes actively controlled magnetic bearing to provide noncontacting vernier pointing and translational isolation of the experiment. The design of the system is presented and analyzed.

  10. Analysis of a suspension system for a wheel rolling on a flat track

    NASA Technical Reports Server (NTRS)

    Mcginness, H.

    1978-01-01

    A flexure strut wheel suspension system is described which keeps a wheel flat against the track and maintains a small interface moment. Equations are presented for the evaluation of this moment. A comparison of the flexure strut system is made with a rigid link design containing pivot bearings.

  11. Design approaches and parameters for magnetically levitated transport systems. [Null flux suspension (Maglev)

    SciTech Connect

    Danby, G.T.; Powell, J.R.

    1988-01-01

    Mechanically levitated transport system approaches are assessed with regard to thrust power needs, track cost, suspension stability, and safety. The null flux suspension appears as the favored approach, having the least thrust power requirements, highest stability, and lowest amount of track material. Various null flux configurations are described together with their operating parameters. The Linear Synchronous Motor (LSM) propulsion system is also described for propelling the suspended vehicles. Cryogenics and superconductivity aspects are discussed and the effect of high T/sub c/ superconductors evaluated. 13 refs., 16 figs., 2 tabs.

  12. Analytical model of a five degree of freedom magnetic suspension and positioning system

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.

    1989-01-01

    An analytical model of a five degree of freedom magnetic suspension and positioning system is presented. The suspended element is a cylinder which is composed of permanent magnet material and the magnetic actuators are air core electromagnets mounted in a planar array. The analytical model consists of an open loop representation of the suspension and positioning system with electromagnet currents as inputs and displacements and rates in inertial coordinates as outputs. The uncontrolled degree of freedom is rotation about the long axis of the suspended cylinder.

  13. Effects of the Truck Suspension System on Animal Welfare, Carcass and Meat Quality Traits in Pigs.

    PubMed

    Dalla Costa, Filipe Antônio; Lopes, Letícia S; Dalla Costa, Osmar Antônio

    2017-01-18

    The objective of this study was to assess the effects of two types of commercial suspension (leaf-spring (LS) vs. air suspension (AS)) installed on two similar double-decked trucks on blood cortisol and lactate concentration, lairage behavior, carcass skin lesions and pork quality traits of 120 crossbred pigs. The suspension type neither influenced pig behaviour in lairage nor blood cortisol and lactate concentrations (p > 0.10). However, when compared with the AS suspension system, the use of LS increased the number of skin lesions in the back and thigh (p = 0.03 and p = 0.01, respectively) and produced thigh with lower pHu (p < 0.001) and yellower colour (higher b* value; p = 0.03), and paler back muscles (subjective colour; p < 0.05), with a tendency to lower pH (p = 0.06). Therefore, the use air suspension system can improve carcass and meat quality traits of pigs transported to slaughter.

  14. Note: low temperature superconductor superconducting quantum interference device system with wide pickup coil for detecting small metallic particles.

    PubMed

    Kandori, Akihiko; Ogata, Kuniomi; Kawabata, Ryuzo; Tanimoto, Sayaka; Seki, Yusuke

    2012-07-01

    A one-channel low temperature superconductor superconducting quantum interference device system comprising a second-order axial gradiometer with a sensing area of 10 mm × 190 mm was developed. The gradiometer was mounted in a liquid-helium dewar (450-mm diameter; 975-mm length), with a gap of 12 mm between the pickup coil and the dewar-tail surface. The magnetic field sensitivity was measured to be 16 fT/Hz(1/2) in the white noise regime above 2 Hz. The system was used to measure stainless steel particles of different sizes passing through the sensing area. A 100-μm diameter SUS304 particle was readily detected passing at different positions underneath the large pickup coil by measuring its 1.3-pT magnetic field. Thus, the system was shown to be applicable to quality control of lamination sheet products such as lithium ion batteries.

  15. Design and implementation of a novel rotary micropositioning system driven by linear voice coil motor.

    PubMed

    Xu, Qingsong

    2013-05-01

    Limited-angle rotary micropositioning stages are required in precision engineering applications where an ultrahigh-precision rotational motion within a restricted range is needed. This paper presents the design, fabrication, and control of a compliant rotary micropositioning stage dedicated to the said applications. To tackle the challenge of achieving both a large rotational range and a compact size, a new idea of multi-stage compound radial flexure is proposed. A compact rotary stage is devised to deliver an over 10° rotational range while possessing a negligible magnitude of center shift. The stage is driven by a linear voice coil motor and its output motion is measured by laser displacement sensors. Analytical models are derived to facilitate the parametric design, which is validated by conducting finite element analysis. The actuation and sensing issues are addressed to guarantee the stage performance. A prototype is fabricated and a proportional-integral-derivative control is implemented to achieve a precise positioning. Experimental results demonstrate a resolution of 2 μrad over 10° rotational range as well as a low level of center shift of the rotary micropositioning system.

  16. Design and experiment study of a semi-active energy-regenerative suspension system

    NASA Astrophysics Data System (ADS)

    Shi, Dehua; Chen, Long; Wang, Ruochen; Jiang, Haobin; Shen, Yujie

    2015-01-01

    A new kind of semi-active energy-regenerative suspension system is proposed to recover suspension vibration energy, as well as to reduce the suspension cost and demands for the motor-rated capacity. The system consists of an energy-regenerative damper and a DC-DC converter-based energy-regenerative circuit. The energy-regenerative damper is composed of an electromagnetic linear motor and an adjustable shock absorber with three regulating levels. The linear motor just works as the generator to harvest the suspension vibration energy. The circuit can be used to improve the system’s energy-regenerative performance and to continuously regulate the motor’s electromagnetic damping force. Therefore, although the motor works as a generator and damps the isolation without an external power source, the motor damping force is controllable. The damping characteristics of the system are studied based on a two degrees of freedom vehicle vibration model. By further analyzing the circuit operation characteristics under different working modes, the double-loop controller is designed to track the desired damping force. The external-loop is a fuzzy controller that offers the desired equivalent damping. The inner-loop controller, on one hand, is used to generate the pulse number and the frequency to control the angle and the rotational speed of the step motor; on the other hand, the inner-loop is used to offer the duty cycle of the energy-regenerative circuit. Simulations and experiments are conducted to validate such a new suspension system. The results show that the semi-active energy-regenerative suspension can improve vehicle ride comfort with the controllable damping characteristics of the linear motor. Meanwhile, it also ensures energy regeneration.

  17. A 20-Channel Receive-Only Mouse Array Coil for a 3T Clinical MRI System

    PubMed Central

    Keil, Boris; Wiggins, Graham C.; Triantafyllou, Christina; Wald, Lawrence L.; Meise, Florian M.; Schreiber, Laura M.; Klose, Klaus J.; Heverhagen, Johannes T.

    2010-01-01

    A 20-channel phased-array coil for Magnetic Resonance Imaging (MRI) of mice has been designed, constructed and validated with bench measurements and high resolution accelerated imaging. The technical challenges of designing a small, high density array have been overcome using individual small-diameter coil elements arranged on a cylinder in a hexagonal overlapping design with adjacent low impedance preamplifiers to further decouple the array elements. Signal-to-noise ratio (SNR) and noise amplification in accelerated imaging were simulated and quantitatively evaluated in phantoms and in vivo mouse images. Comparison between the 20-channel mouse array and a length-matched quadrature driven small animal birdcage coil showed an SNR increase at the periphery and in the center of the phantom of 3-fold and 1.3-fold, respectively. Comparison to a shorter but SNR-optimized birdcage coil (aspect ratio 1:1 and only half mouse coverage) showed an SNR gain of 2-fold at the edge of the phantom and similar SNR in the center. G-factor measurements indicate that the coil is well suited to acquire highly accelerated images. PMID:21433066

  18. A 20-channel receive-only mouse array coil for a 3 T clinical MRI system.

    PubMed

    Keil, Boris; Wiggins, Graham C; Triantafyllou, Christina; Wald, Lawrence L; Meise, Florian M; Schreiber, Laura M; Klose, Klaus J; Heverhagen, Johannes T

    2011-08-01

    A 20-channel phased-array coil for MRI of mice has been designed, constructed, and validated with bench measurements and high-resolution accelerated imaging. The technical challenges of designing a small, high density array have been overcome using individual small-diameter coil elements arranged on a cylinder in a hexagonal overlapping design with adjacent low impedance preamplifiers to further decouple the array elements. Signal-to-noise ratio (SNR) and noise amplification in accelerated imaging were simulated and quantitatively evaluated in phantoms and in vivo mouse images. Comparison between the 20-channel mouse array and a length-matched quadrature driven small animal birdcage coil showed an SNR increase at the periphery and in the center of the phantom of 3- and 1.3-fold, respectively. Comparison with a shorter but SNR-optimized birdcage coil (aspect ratio 1:1 and only half mouse coverage) showed an SNR gain of twofold at the edge of the phantom and similar SNR in the center. G-factor measurements indicate that the coil is well suited to acquire highly accelerated images. Copyright © 2011 Wiley-Liss, Inc.

  19. Coiled-coil protein composition of 22 proteomes – differences and common themes in subcellular infrastructure and traffic control

    PubMed Central

    Rose, Annkatrin; Schraegle, Shannon J; Stahlberg, Eric A; Meier, Iris

    2005-01-01

    Background Long alpha-helical coiled-coil proteins are involved in diverse organizational and regulatory processes in eukaryotic cells. They provide cables and networks in the cyto- and nucleoskeleton, molecular scaffolds that organize membrane systems and tissues, motors, levers, rotating arms, and possibly springs. Mutations in long coiled-coil proteins have been implemented in a growing number of human diseases. Using the coiled-coil prediction program MultiCoil, we have previously identified all long coiled-coil proteins from the model plant Arabidopsis thaliana and have established a searchable Arabidopsis coiled-coil protein database. Results Here, we have identified all proteins with long coiled-coil domains from 21 additional fully sequenced genomes. Because regions predicted to form coiled-coils interfere with sequence homology determination, we have developed a sequence comparison and clustering strategy based on masking predicted coiled-coil domains. Comparing and grouping all long coiled-coil proteins from 22 genomes, the kingdom-specificity of coiled-coil protein families was determined. At the same time, a number of proteins with unknown function could be grouped with already characterized proteins from other organisms. Conclusion MultiCoil predicts proteins with extended coiled-coil domains (more than 250 amino acids) to be largely absent from bacterial genomes, but present in archaea and eukaryotes. The structural maintenance of chromosomes proteins and their relatives are the only long coiled-coil protein family clearly conserved throughout all kingdoms, indicating their ancient nature. Motor proteins, membrane tethering and vesicle transport proteins are the dominant eukaryote-specific long coiled-coil proteins, suggesting that coiled-coil proteins have gained functions in the increasingly complex processes of subcellular infrastructure maintenance and trafficking control of the eukaryotic cell. PMID:16288662

  20. Operational Loopwheel Suspension System for Mars Rover Demonstration Model

    NASA Technical Reports Server (NTRS)

    Trautwein, W.; Robinson, G. D.

    1978-01-01

    The loopwheel (or elastic loop) mobility concept, appears to be uniquely qualified to provide a high degree of mobility at low weight and stowage requirements for the next Mars mission now in the early planning stage. Traction elements compatible with sterilization and Mars surface environmental constraints were designed and are compatible with the rover mass, range and stowage requirements of JPL's point design Mars rover. In order to save cost, the loopwheel suspensions for the demonstration model were made of S-glass/epoxy instead of titanium, alloy specified for flight units. The load carrying fiberglass loop core is covered by a rubber tread on the outside. Reinforced rubber gear belts bonded along the inside edges provide positive engagement and transmission drive torques. A 12 Vdc drive motor with a 167:1 gear head is installed in the payload section of the hull. A chain drive transmits the motor power to the rear sprocket in the demonstration model, whereas future flight units would be directly driven by brushless hub motors within each sprocket and independent four-leg height control.

  1. Eddy Current Influences on the Dynamic Behaviour of Magnetic Suspension Systems

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.; Bloodgood, Dale V.

    1998-01-01

    This report will summarize some results from a multi-year research effort at NASA Langley Research Center aimed at the development of an improved capability for practical modelling of eddy current effects in magnetic suspension systems. Particular attention is paid to large-gap systems, although generic results applicable to both large-gap and small-gap systems are presented. It is shown that eddy currents can significantly affect the dynamic behavior of magnetic suspension systems, but that these effects can be amenable to modelling and measurement. Theoretical frameworks are presented, together with comparisons of computed and experimental data particularly related to the Large Angle Magnetic Suspension Test Fixture at NASA Langley Research Center, and the Annular Suspension and Pointing System at Old Dominion University. In both cases, practical computations are capable of providing reasonable estimates of important performance-related parameters. The most difficult case is seen to be that of eddy currents in highly permeable material, due to the low skin depths. Problems associated with specification of material properties and areas for future research are discussed.

  2. Designing with null flux coils

    SciTech Connect

    Davey, K.R.

    1997-09-01

    Null flux were suggested by Danby and Powell in the late 1960`s as a useful means for realizing induced lift with little drag. As an array of alternating magnets is translated past a set of null flux coils, the currents induced in these coils act to vertically center the magnets on those coils. At present, one Japanese MAGLEV system company and two American-based companies are employing either null flux or flux eliminating coils in their design for high speed magnetically levitated transportation. The principle question addressed in paper is: what is the proper choice of coil length to magnet length in a null flux system? A generic analysis in the time and frequency domain is laid out with the intent of showing the optimal design specification in terms of coil parameters.

  3. Design concepts and cost studies for magnetic suspension and balance systems. [wind tunnel apparatus

    NASA Technical Reports Server (NTRS)

    Bloom, H. L.

    1982-01-01

    The application of superconducting magnets for suspension and balance of wind tunnel models was studied. Conceptual designs are presented for magnetic suspension and balance system (MSBS) configurations compatible with three high Reynolds number cases representing specified combinations of test conditions and model sizes. Concepts in general met initially specified performance requirements such as duty cycle, force and moment levels, model angular displacement and positioning accuracy with nominal design requirements for support subsystems. Other performance requirements, such as forced model sinusoidal oscillations, and control force magnitude and frequency, were modified so as to alleviate the magnitude of magnet, power, and cryogenic design requirements.

  4. A forecast of new test capabilities using Magnetic Suspension and Balance Systems

    NASA Technical Reports Server (NTRS)

    Lawing, Pierce L.; Johnson, William G., Jr.

    1988-01-01

    This paper outlines the potential of Magnetic Suspension and Balance System (MSBS) technology to solve existing problems related to support interference in wind tunnels. Improvement of existing test techniques and exciting new techniques are envisioned as a result of applying MSBS. These include improved data accuracy, dynamic stability testing, two-body/stores release testing, and pilot/designer-in-the-loop tests. It also discusses the use of MSBS for testing exotic configurations such as hybrid hypersonic vehicles. A new facility concept that combines features of ballistic tubes, magnetic suspension, and cryogenic tunnels is described.

  5. Fallback options for airgap sensor fault of an electromagnetic suspension system

    NASA Astrophysics Data System (ADS)

    Michail, Konstantinos; Zolotas, Argyrios; Goodall, Roger

    2013-06-01

    The paper presents a method to recover the performance of an electromagnetic suspension under faulty airgap sensor. The proposed control scheme is a combination of classical control loops, a Kalman Estimator and analytical redundancy (for the airgap signal). In this way redundant airgap sensors are not essential for reliable operation of this system. When the airgap sensor fails the required signal is recovered using a combination of a Kalman estimator and analytical redundancy. The performance of the suspension is optimised using genetic algorithms and some preliminary robustness issues to load and operating airgap variations are discussed. Simulations on a realistic model of such type of suspension illustrate the efficacy of the proposed sensor tolerant control method.

  6. 76 FR 41855 - Columbus Geographic Systems (GIS) Ltd.; Order of Suspension of Trading

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Columbus Geographic Systems (GIS) Ltd.; Order of Suspension of Trading July 13, 2011. It appears to the Securities and Exchange Commission that there is a lack of current and accurate information concerning the securities of Columbus...

  7. Application of Magnetic Suspension and Balance Systems to Ultra-High Reynolds Number Facilities

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.

    1996-01-01

    The current status of wind tunnel magnetic suspension and balance system development is briefly reviewed. Technical work currently underway at NASA Langley Research Center is detailed, where it relates to the ultra-high Reynolds number application. The application itself is addressed, concluded to be quite feasible, and broad design recommendations given.

  8. Wheeled Vehicle Drive Lines, Axles, and Suspension Systems. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Army Ordnance Center and School, Aberdeen Proving Ground, MD.

    This course is one of several subcourses that make up the entire Army correspondence course on wheeled vehicle maintenance. The subcourse is designed to provide the student with information about the operation, malfunction diagnosis, maintenance, and repair of wheeled vehicle drive lines, axles, and suspension systems. It provides the basic…

  9. 78 FR 37269 - Order of Suspension of Trading; iTrackr Systems, Inc.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ... COMMISSION Order of Suspension of Trading; iTrackr Systems, Inc. June 18, 2013. It appears to the Securities... trading in the securities of iTrackr. Therefore, it is ordered, pursuant to Section 12(k) of the Securities Exchange Act of 1934, that trading in the securities of iTrackr is suspended for the period from...

  10. V-TECS Guide for Auto Mechanics: Suspension Systems, Brakes and Steering.

    ERIC Educational Resources Information Center

    Moore, Charles G.; And Others

    The materials in this document are an extension of a catalog of occupational duties, tasks, and performance objectives relevant to maintaining automotive suspension systems, brakes, and steering mechanisms. This document provides the following for each occupational task within each duty: (1) a standard of performance; (2) the conditions under…

  11. Designing an Acoustic Suspension Speaker System in the General Physics Laboratory: A Divergent experiment

    ERIC Educational Resources Information Center

    Horton, Philip B.

    1969-01-01

    Describes a student laboratory project involving the design of an "acoustic suspension speaker system. The characteristics of the loudspeaker used are measured as an extension of the inertia-balance experiment. The experiment may be extended to a study of Stelmholtz resonators, coupled oscillators, electromagnetic forces, thermodynamics and…

  12. 2 CFR 180.125 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2 Grants and Agreements 1 2010-01-01 2010-01-01 false What is the purpose of the nonprocurement debarment and suspension system? 180.125 Section 180.125 Grants and Agreements OFFICE OF MANAGEMENT AND BUDGET GOVERNMENTWIDE GUIDANCE FOR GRANTS AND AGREEMENTS Reserved OMB GUIDELINES TO AGENCIES ON...

  13. V-TECS Guide for Auto Mechanics: Suspension Systems, Brakes and Steering.

    ERIC Educational Resources Information Center

    Moore, Charles G.; And Others

    The materials in this document are an extension of a catalog of occupational duties, tasks, and performance objectives relevant to maintaining automotive suspension systems, brakes, and steering mechanisms. This document provides the following for each occupational task within each duty: (1) a standard of performance; (2) the conditions under…

  14. Designing an Acoustic Suspension Speaker System in the General Physics Laboratory: A Divergent experiment

    ERIC Educational Resources Information Center

    Horton, Philip B.

    1969-01-01

    Describes a student laboratory project involving the design of an "acoustic suspension speaker system. The characteristics of the loudspeaker used are measured as an extension of the inertia-balance experiment. The experiment may be extended to a study of Stelmholtz resonators, coupled oscillators, electromagnetic forces, thermodynamics and…

  15. Experimental Validation of a Multibody Dynamics Model of the Suspension System of a Tracked Vehicle

    DTIC Science & Technology

    2011-08-09

    of the suspension system rotational deflections are experimentally measured for the various input motion excitations. The experimental measurements...including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson...large rotations and large deflections (of the flexible track). A review of flexible multibody dynamics modeling techniques including deformation

  16. 22 CFR 208.110 - What is the purpose of the nonprocurement debarment and suspension system?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false What is the purpose of the nonprocurement debarment and suspension system? 208.110 Section 208.110 Foreign Relations AGENCY FOR INTERNATIONAL... Government ensures the integrity of Federal programs by conducting business only with responsible persons....

  17. 93. 22'X34' original blueprint, VariableAngle Launcher, 'OVERHEAD CAMERA SUSPENSION SYSTEM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    93. 22'X34' original blueprint, Variable-Angle Launcher, 'OVERHEAD CAMERA SUSPENSION SYSTEM, TOWER STAY CABLES' drawn at 3/4'=1'-0'. (BUORD Sketch # 208783). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  18. Pulse Coil Tester

    NASA Technical Reports Server (NTRS)

    Simon, Richard A.

    1988-01-01

    Set of relays tested easily and repeatedly. Pulse coil tester causes coil under test to generate transient voltage; waveform indicates condition of coil. Tester accommodates assembly of up to four coils at a time.

  19. An efficient recursive least square-based condition monitoring approach for a rail vehicle suspension system

    NASA Astrophysics Data System (ADS)

    Liu, X. Y.; Alfi, S.; Bruni, S.

    2016-06-01

    A model-based condition monitoring strategy for the railway vehicle suspension is proposed in this paper. This approach is based on recursive least square (RLS) algorithm focusing on the deterministic 'input-output' model. RLS has Kalman filtering feature and is able to identify the unknown parameters from a noisy dynamic system by memorising the correlation properties of variables. The identification of suspension parameter is achieved by machine learning of the relationship between excitation and response in a vehicle dynamic system. A fault detection method for the vertical primary suspension is illustrated as an instance of this condition monitoring scheme. Simulation results from the rail vehicle dynamics software 'ADTreS' are utilised as 'virtual measurements' considering a trailer car of Italian ETR500 high-speed train. The field test data from an E464 locomotive are also employed to validate the feasibility of this strategy for the real application. Results of the parameter identification performed indicate that estimated suspension parameters are consistent or approximate with the reference values. These results provide the supporting evidence that this fault diagnosis technique is capable of paving the way for the future vehicle condition monitoring system.

  20. Multiobjective Robust Design of the Double Wishbone Suspension System Based on Particle Swarm Optimization

    PubMed Central

    Lin, Yuqun

    2014-01-01

    The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system. PMID:24683334

  1. Multiobjective robust design of the double wishbone suspension system based on particle swarm optimization.

    PubMed

    Cheng, Xianfu; Lin, Yuqun

    2014-01-01

    The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system.

  2. A review of dynamic stability of repulsive-force maglev suspension systems

    SciTech Connect

    Cai, Y.; Rote, D.M.

    1998-07-01

    Vehicle dynamics and the need to satisfy ride quality requirements have long been recognized as crucial to the commercial success of passenger-carrying transportation systems. Design concepts for maglev systems are no exception. Early maglev investigators and designers were well aware of the importance of ride quality and took care to ensure that their designs would meet acceptable ride quality standards. In contrast, the dynamic stability of electrodynamic suspension (EDS) systems, which has obvious implications for system safety and cost as well as for ride quality, has not received nearly as much attention. Because of the well-known under-damped nature of EDS suspension systems and the observation of instabilities in laboratory-scale model systems, it is prudent to develop a better understanding of vehicle stability characteristics. The work reported in this was undertaken with the intention of summarizing information that has been accumulated worldwide and that is relevant to dynamic stability of repulsive-force maglev suspension systems, assimilating that information, and gaining an understanding of the factors that influence that stability. Included in the paper is a discussion and comparison of results acquired from some representative tests of large-scale vehicles on linear test tracks, together with analytical and laboratory-scale investigations of stability and dynamics of EDS systems. This paper will also summarize the R and D activities at Argonne National Laboratory (ANL) since 1991 to study the nature of the forces that are operative in an EDS system and the dynamic stability of such systems.

  3. Research on high acceleration high precision air suspension control system performance evaluation algorithm

    NASA Astrophysics Data System (ADS)

    Ling, Xiang; Zhang, Yu

    2017-07-01

    The motion performance of the high acceleration high precision air suspension platform is affected by the electromechanical characteristics of the drive system, the fluid characteristics of the air suspension guide rail and the load disturbance. The mathematical model of the system is established, and the controller performance is designed based on the optimal objective function value. The ideal controller performance is proposed as the evaluation benchmark. The performance of the system is evaluated by the ratio of the optimal objective value and the evaluation benchmark. Based on the established evaluation index, the influence of noise disturbance and estimation vector on the stability and robustness of the system is evaluated, and the system performance is further optimized.

  4. The gyroscope testbed: A verification of the gravity probe B suspension system

    NASA Astrophysics Data System (ADS)

    Brumley, Robert Willard

    The verification of precision control systems for use in space-based applications can be extremely challenging. Often, the presence of the 1-g field substantively changes the control problem, making it impossible to test directly on the Earth. This talk discusses a new approach to testing and verification of the gyroscope suspension system for the Gravity Probe B (GP-B) experimental test of General Relativity. The verification approach involves the creation of a new testbed that has the same input-output characteristics and dynamics as a GP-B gyroscope. This involves real physical hardware that moves like a real gyroscope, allowing the suspension system's performance to be measured directly without the need to break any internal connections or bypass internal subsystems. The user free to define any set of disturbances from a 1-g ground levitation to a 10-8 g science mission. The testbed has two main subsystems. The mechanical subsystem is comprised of six parallel plate capacitors whose spacing is controlled by precision actuators. These actuators are the physical interface to the suspension system and create the electrode-rotor capacitances present in a real gyroscope. The closed-loop positioning noise of the system is approximately 10 pm/√Hz, enabling the commanding of position variations a fraction the size of a single atom of Silicon. The control subsystem has a DSP-based high-speed nonlinear controller that forces the actuators to follow the dynamics of a gyroscope. The device has been shown to faithfully represent a gyroscope in 1-g levitation, and a robustness analysis has been performed to prove that it correctly tests the stability of the on-orbit system. The testbed is then used to measure directly suspension system performance in a variety of on-orbit scenarios. Gyroscope levitation in 10-8 g conditions is demonstrated. The robustness of gyroscope levitation to transient disturbances such as micrometeorite impacts on the space vehicle and transitions

  5. Dynamic response of a vehicle with planar suspension system (PSS) under differential braking

    NASA Astrophysics Data System (ADS)

    Zhu, Jian Jun; Khajepour, Amir; Esmailzadeh, Ebrahim

    2012-01-01

    To absorb the vibrations and shocks caused by road obstacles effectively in any direction within the wheel rotation plane, a planar suspension system (PSS), in which there are spring-damper struts in both the vertical and longitudinal directions, is proposed to improve the ride quality of a vehicle with such novel suspension systems. The longitudinal spring-damper strut in a PSS is considerably soft compared with the longitudinal connection in a conventional suspension. Consequently, the wheels in a vehicle with PSS can move forth and back with respect to the body. The dynamic behaviours of a PSS vehicle under some special conditions, such as a differential braking in which the braking torque applied to the wheels at two sides of an axle are uneven, may exhibit special characteristics. The directional stability of the PSS vehicle in such a case may be one of the major concerns. The dynamic performance of the PSS vehicle in the differential braking condition is thus necessary to be investigated. This paper presents the investigation results of the transient response of a vehicle with the PSS in such a case. The simulation results are also compared with those of a similar vehicle with conventional suspensions. The study demonstrates that the PSS vehicle is directionally stable in differential braking conditions. The dynamic behaviour of the PSS vehicle is generally comparable with that of a conventional vehicle.

  6. 45 CFR 307.40 - Suspension of approval of advance planning documents for computerized support enforcement systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Suspension of approval of advance planning...), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES COMPUTERIZED SUPPORT ENFORCEMENT SYSTEMS § 307.40 Suspension of approval of advance planning documents for computerized support...

  7. An airfoil flutter model suspension system to accommodate large static transonic airloads

    NASA Technical Reports Server (NTRS)

    Reed, W. H., III

    1985-01-01

    A pitch/plunge flutter model suspension system and associated two-dimensional MBB-A3 airfoil models is described. The system is designed for installation in the Langley 6-by-19-inch and 6-by-18-inch transonic blowdown wind tunnels to enable systematic study of the transonic flutter characteristics and static pressure distributions of supercritical airfoils at transonic Mach numbers. A compound spring suspension concept is introduced which simultaneously meets requirements for low plunge-mode stiffness, lightweight suspended model, and large steady lift due to angle of attack without the need for excessive static deflections of the plunge spring. The system features variable pitch and plunge frequencies, changeable airfoil rotation axes, and a self aligning control system to maintain a constant mean position of the model with changing airload.

  8. Modeling and simulation on temperature performance in fiber optic gyroscope fiber coil of shipborne strapdown inertial navigation system

    NASA Astrophysics Data System (ADS)

    Wang, Yueze; Ma, Lin; Yu, Hao; Gao, Hongyu; Yuan, Yujie

    2016-10-01

    Compared with the traditional gyros, Fiber optic gyroscope (FOG) based on sagnac effect has the significant features, such as, long life, low cost, wide dynamic range, etc. These features have developed new applications of the gyroscope not only in industrial application area but also in aerospace application area. Now, the FOG has played a very important role in shipborne Strapdown Inertial Navigation System (SINS). The fiber coil, as one of the most critical components in FOG, is extremely sensitive to changes in temperature. Here, by study the environment temperature in shipborne SINS, the temperature performance of the FOG was analyzed. Firstly, on the base of the research about the theory of Shupe non-reciprocal errors caused by temperature, the discrete mathematics formula of the temperature error in FOG of SINS was built .Then the element model of the fiber coil in SINS was built based on the discrete model of the fiber coil in temperature error in FOG. A turn-by-turn quantization temperature bias error model is establish. Finally, based on the temperature models mentioned above, the temperature performance of FOG in shipborne SINS was analyzed. With finite element analysis, numerical simulations were carried out to quantitatively analyze the angular error induced by temperature excitation in SINS. The model was validated by comparing numerical and experimental results.

  9. Eddy Current Loss Induced in Aluminum Thermal Conduction Strips for ASPCS Coils Indirectly Cooled by Liquid Hydrogen through Thermo-siphon System

    NASA Astrophysics Data System (ADS)

    Ota, Narumi; Katsura, Masashi; Ando, Kennosuke; Takao, Tomoaki; Shintomi, Takakazu; Makida, Yasuhiro; Hamajima, Takataro; Tsuda, Makoto; Miyagi, Daisuke; Tsujigami, Hiroshi; Fujikawa, Shizuichi; Semba, Toshiaki; Iwaki, Katsuya

    To promote renewable energy sources, we proposed a new system called the Advanced Superconducting Power Conditioning System (ASPCS), which consists of Superconducting Magnetic Energy Storage-system (SMES), Electrolyzer, and Fuel Cell, and is also combined with a liquid hydrogen station for vehicles. The SMES plays a role to compensate the fast fluctuations generated by the renewable energies. In case of the ASPCS with a capacity of 5 MW, we designed the 50 MJ-class SMES composed of 4 solenoid coils. The winding of the solenoid coils is double pancake and a basic coil is 2 m in diameter and 0.5 m in height. Each SMES coil is wound with MgB2 conductor and indirectly cooled at 20 K by liquid hydrogen flowing through a thermo-siphon cooling system. Pure aluminum strips are inserted between the double-pancake coils and the pure aluminum plates gathering the strips lead to liquid hydrogen pipes. This scheme enables the strips and the plates to transfer the heat load in the coils to the cooling pipes and keep the coils at low temperature. On the other hand, we must consider that the strips generate eddy current loss which is strongly affected by a width of the strips. At the same time as the primary study of the SMES coils, we experimented on the thermo-siphon cooling system and investigated the relationship between the heat load and the heat extraction ability of the cooling system. The experiments showed that the cooling system could proficiently function. The estimation of eddy current loss from the particular cooling aluminum strips for the SMES in the ASPCS is reported with the results of the thermo-siphon driving experiment.

  10. Magnetic Coiling

    NASA Image and Video Library

    2016-07-18

    One broad active region sported a wonderful example of coiled magnetic field lines over almost a four-day period (July 15-18, 2016). The magnetic lines are easily visible in this 171 Angstrom wavelength of extreme ultraviolet light be cause charged particles are spiraling along the lines. The active region is a hotbed of struggling magnetic forces that were pushing out above the sun's surface. http://photojournal.jpl.nasa.gov/catalog/PIA17911

  11. A square-loop Helmholtz coil system for the evaluation of a single-layer second-order high- Tc SQUID gradiometer

    NASA Astrophysics Data System (ADS)

    Lee, Soon-Gul; Kang, Chan Seok; Chang, Jung Won

    2007-09-01

    We have designed and fabricated a square-loop Helmholtz coil system to balance and calibrate a second-order SQUID gradiometer, and measured the field distribution in the midplane. It consists of two pairs of identical square loops, one for generating uniform fields, which is a Helmholtz coil pair, and the other for generating the second-order field gradient by subtracting the Helmholtz coils’ field with equal magnitude at the center. We obtained analytical expressions in power series up to the fourth-order of the fields in the midplane and along the coil axis, and measured the field distributions for both Helmholtz and second-order gradient modes.

  12. Preliminary investigations of design philosophies and features applicable to large magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Britcher, C. P.; Fortescue, P. W.; Allcock, G. A.; Goodyer, M. J.

    1979-01-01

    The technology which is required to allow the principles of magnetic suspension and balance systems (MSBS) to be applied to the high Reynolds number transonic testing of aircraft models is examined. A test facility is presented as comprising a pressurized transonic cryogenic wind tunnel, with the MSBS providing full six degree of freedom control. The electro-magnets which are superconducting and fed from quiet, bipolar power supplies are examined. A model control system having some self adaptive characteristics is discussed.

  13. Dynamic stability of rotating flexible disk perturbed by the reciprocating angular movement of suspension-slider system

    NASA Astrophysics Data System (ADS)

    Pei, Yong-Chen; Tan, Qing-Chang; Zheng, Fu-Sheng; Zhang, Yong-Qi

    2010-12-01

    To simulate the dynamic process of a magnetic head reading/writing data in a hard disk drive, a rotating flexible thin disk perturbed by the reciprocating angular movement of a suspension-slider system is modelled, where the suspension-slider system is considered as a mass-damping-spring loading system. A system dynamic model is formulated as a parametrically excited system, and its dynamic stability is studied by Hill's method involving harmonic balance. The reciprocating angular movement of the suspension-slider system causes system parametric instability at some angular movement frequencies. The large-amplitude angular movement is especially dangerous, and angular movement frequency must be reduced when the slider works at large radii of the disk. The parametric instability can be avoided or suppressed by operating at: low-frequency and small-amplitude reciprocating angular movement, small mass, large natural frequency and damping of the suspension-slider system, and low-speed rotation of the disk.

  14. Microbial spoilage, instability risk of antacid suspension in the presence of commonly used preservative system.

    PubMed

    Khan, Jamshaid Ali; Khan, Imran Ullah; Iqbal, Zafar; Nasir, Fazli; Muhammad, Salar; Hannan, Peer Abdul; Ullah, Irfan

    2015-09-01

    Manifestation of microbial spoilage of any product by bacteria and to assess the effectiveness of the anti-microbial preservatives (parabens) used for the prevention and stability purpose. The aim of the present work is to study the effectiveness of preservatives used in the antacid suspensions and to analyze the effect of microbial growth on the quality of respective antacid suspensions. Samples of various antacid suspensions were randomly collected from local market and Government hospital pharmacies. Three different antacid formulations were prepared in the laboratory. All the formulations were preliminarily evaluated on the basis of organoleptic characteristics, pH, viscosity and assay. Efficacy of the preservative system in suspension formulation was determined by inoculating the samples in its final container, with specific strains of bacteria i.e. Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538, taking samples from the inoculated preparation at specified intervals of time i.e. 0 time, 07 days, 14 days and 28 days, growing it on nutrient agar medium and colony forming units (CFUs) were scored by plate count. At the same time the samples were also subjected to qualitative and quantitative testing. The decrease in CFU and alteration in assay, pH and viscosity was observed in all the formulations except formulation M2 and F3 that showed stability throughout the study period.

  15. The effects of wheelset driving system suspension parameters on the re-adhesion performance of locomotives

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Zhao, Shiyin; Xiao, Feixiong; Liu, Jianxin

    2015-12-01

    In this study, in order to examine the effects of a wheelset driving system suspension parameters on the re-adhesion performance of locomotives, the stick-slip vibration was analysed according to theoretical and simulation analysis. The decrease of the slip rate vibration amplitude improved the stability of the stick-slip vibration and the re-adhesion performance of locomotives. Increasing the longitudinal guide stiffness of the wheelset and the motor suspension stiffness were proposed as effective measures to improve the re-adhesion performance of locomotives. These results showed that the dynamic slip rate was inversely proportional to the series result of the square root of the longitudinal guide and motor suspension stiffness. The larger the motor suspension stiffness was, the smaller the required longitudinal guidance stiffness was at the same re-adhesion time once the wheel slip occurred, and vice versa. The simulation results proved that the re-adhesion time of the locomotive was approximately proportional to amplitude of the dynamic slip rate. When the stick-slip vibration occurred, the rotary and the longitudinal vibrations of the wheelset were coupled, which was confirmed by train's field tests.

  16. COIL technology development at Boeing

    NASA Astrophysics Data System (ADS)

    Hurlock, Steve C.

    2002-05-01

    The historical COIL contributions at the McDonnell Douglas Research Laboratory, the Rocketdyne Division of Rockwell International and Boeing's Laser and Electro-Optic Systems organization are briefly described. The latter organization now contains the capabilities of the two heritage organizations. Boeing's new high pressure sealed COIL is also described.

  17. Magnetic suspension system for an Annular Momentum Control Device (AMCD)

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A technique to control a rim suspended in a magnetic field was developed. A complete system was developed, incorporating a support structure, magnetic actuators, a rim drive mechanism, an emergency fail-safe system, servo control system, and control electronics. Open loop and closed loop response of the system at zero speed and at 500 revolutions per minute (r/min) of the rim was obtained and analyzed. The rim was then dynamically balanced and a rim speed of 725 r/min was achieved. An analog simulation of the hardware was developed and tested with the actual control electronics connected to the analog computer. The system under development is stable at rim speeds below 700 r/min. Test results indicate that the rim under test is not rigid. The rim has a warp and a number of binding modes which prevented achievement of higher speeds. Further development efforts are required to achieve higher rim speeds.

  18. Vehicle height and posture control of the electronic air suspension system using the hybrid system approach

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoqiang; Cai, Yingfeng; Chen, Long; Liu, Yanling; Wang, Shaohua

    2016-03-01

    The electronic air suspension (EAS) system can improve ride comfort, fuel economy and handling safety of vehicles by adjusting vehicle height. This paper describes the development of a novel controller using the hybrid system approach to adjust the vehicle height (height control) and to regulate the roll and pitch angles of the vehicle body during the height adjustment process (posture control). The vehicle height adjustment system of EAS poses challenging hybrid control problems, since it features different discrete modes of operation, where each mode has an associated linear continuous-time dynamic. In this paper, we propose a novel approach to the modelling and controller design problem for the vehicle height adjustment system of EAS. The system model is described firstly in the hybrid system description language (HYSDEL) to obtain a mixed logical dynamical (MLD) hybrid model. For the resulting model, a hybrid model predictive controller is tuned to improve the vehicle height and posture tracking accuracy and to achieve the on-off statuses direct control of solenoid valves. The effectiveness and performance of the proposed approach are demonstrated by simulations and actual vehicle tests.

  19. [Study of building up a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy].

    PubMed

    Zhang, Hongqiang; Tian, Sujing; Yang, Guoqing; Li, Xiaoming

    2015-08-01

    To build up a simple and effective comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. One hundred and twenty cases of laryngeal tubor were selected. Using Logistic regression method to analyse relative factors, including weight, height, BMI, neck girth, neck upward degree, upper-lower incisor teeth distance, thyroid-mentum distance, thyroid-sternum distance, Mallampati test, Yamamoto test and Upper lip bite test. Build data-base to construct a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. The relative factors of difficult laryngeal exposure were BMI, neck girth, upper-lower incisor teeth distance, neck upward degree, thyroid-mentum distance, Mallampati test and Yamamoto test (P < 0.05). To build up a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. The predicting standards included the seven relative factors, each factor has 1 score, 2 score, 3 score. Higher score means more risk. Eight score was designed as minimum, under the premise,the sensibility, misdiagnosis rate, missed misdiagnosis rate, specificity of the experiment were 95.5%, 5.3%, 4.5%, 94.7%. The comprehesive system is an effective method for predicting difficult intubation. It can help to identify difficult cases according to the results of this predicting system.

  20. The effects of the levonorgestrel intrauterine system (Mirena coil) on endometrial morphology

    PubMed Central

    Phillips, V; Graham, C T; Manek, S; McCluggage, W G

    2003-01-01

    Aims: The Mirena coil is a levonorgestrel releasing intrauterine device that is in widespread use. This study aims to document the endometrial morphology associated with this device. Methods: Endometrial specimens from 75 women with the Mirena coil were reviewed and the histological features detailed. Results: Morphological features found in most of the endometria were decidualisation of stroma (72 of 75 cases), atrophy of endometrial glands (65 of 75 cases), a surface papillary pattern (38 of 75 cases), and a stromal inflammatory cell infiltrate (59 of 75 cases). Additional common histological features were the presence of foci of stromal myxoid change (29 of 75 cases) and stromal haemosiderin pigment (24 of 75 cases). Reactive atypia of surface glands, glandular metaplastic changes, stromal necrosis, and stromal calcifications were found in small numbers of cases. Conclusion: The endometrial features are characteristic and relatively constant and are in keeping with the effects of both a progestogenic compound and a mechanical device. Pathologists should be aware of these histological features because the Mirena coil is in widespread use. PMID:12663645

  1. A coil system for real-time magnetic fluid hyperthermia microscopy studies.

    PubMed

    Subramanian, Mahendran; Miaskowski, Arkadiusz; Pearce, Gillian; Dobson, Jon

    2016-01-01

    We describe the design and application of a new apparatus for applying Radiofrequency (RF) electromagnetic fields to cells in culture on a microscope stage. This new design enables real-time studies of the actuation of magnetic nanoparticles bound to membrane receptors or internalised within cells together with the study of magnetic fluid hyperthermia (MFH)-associated effects. RF coils were fabricated and electromagnetic simulations were performed along with compatibility evaluations and calorimetric experiments using this apparatus at discreet frequencies between 100 kHz and 1 MHz. Cell killing via MFH was investigated in a neuroblastoma tumour cell line. Simulations and evaluations showed that the field intensity and homogeneity experienced by the cells within the chamber is best with a planar coil configuration. The incubation chamber was suitable for cell culture and the design was compatible with mountings on different makes of microscopes as it mimics a standard 96/24/6 tissue-culture well plate. Successful calorimetric and MFH cytotoxicity proof-of-principle experiments were performed and are presented. We conclude from these experiments that alternating magnetic field (AMF)-mediated activation and magnetic fluid hyperthermia (MFH) research will benefit from this RF coil that fits inside an incubation chamber, mounted onto a microscope. This new design could be used to assist real-time MFH studies in vitro.

  2. A self-adjustable four-point probing system using polymeric three dimensional coils and non-toxic liquid metal

    SciTech Connect

    Oyunbaatar, Nomin-Erdene; Choi, Young Soo; Lee, Dong-Weon

    2015-12-15

    This paper describes a self-adjustable four-point probe (S4PP) system with a square configuration. The S4PP system consists of 3D polymer coil springs for the independent operation of each tungsten (W) probe, microfluidic channels filled with a nontoxic liquid metal, and a LabView-based control system. The 3D coil springs made by PMMA are fabricated with a 3D printer and are positioned in a small container filled with the non-toxic liquid metal. This unique configuration allows independent self-adjustment of the probe heights for precise measurements of the electrical properties of both flexible and large-step-height microsamples. The feasibility of the fabricated S4PP system is evaluated by measuring the specific resistance of Cr and Au thin films deposited on silicon wafers. The system is then employed to evaluate the electrical properties of a Au thin film deposited onto a flexible and easily breakable silicon diaphragm (spring constant: ∼3.6 × 10{sup −5} N/m). The resistance of the Cr thin films (thickness: 450 nm) with step heights of 60 and 90 μm is also successfully characterized. These experimental results indicate that the proposed S4PP system can be applied to common metals and semiconductors as well as flexible and large-step-height samples.

  3. A self-adjustable four-point probing system using polymeric three dimensional coils and non-toxic liquid metal

    NASA Astrophysics Data System (ADS)

    Oyunbaatar, Nomin-Erdene; Choi, Young Soo; Lee, Dong-Weon

    2015-12-01

    This paper describes a self-adjustable four-point probe (S4PP) system with a square configuration. The S4PP system consists of 3D polymer coil springs for the independent operation of each tungsten (W) probe, microfluidic channels filled with a nontoxic liquid metal, and a LabView-based control system. The 3D coil springs made by PMMA are fabricated with a 3D printer and are positioned in a small container filled with the non-toxic liquid metal. This unique configuration allows independent self-adjustment of the probe heights for precise measurements of the electrical properties of both flexible and large-step-height microsamples. The feasibility of the fabricated S4PP system is evaluated by measuring the specific resistance of Cr and Au thin films deposited on silicon wafers. The system is then employed to evaluate the electrical properties of a Au thin film deposited onto a flexible and easily breakable silicon diaphragm (spring constant: ˜3.6 × 10-5 N/m). The resistance of the Cr thin films (thickness: 450 nm) with step heights of 60 and 90 μm is also successfully characterized. These experimental results indicate that the proposed S4PP system can be applied to common metals and semiconductors as well as flexible and large-step-height samples.

  4. Digital controller design: Analysis of the annular suspension pointing system. [analog controllers with feedback

    NASA Technical Reports Server (NTRS)

    Kuo, B. C.

    1978-01-01

    The analog controllers of the annular suspension pointing system are designed for control of the chi, phi sub 1, and phi sub 2 bandwidth dynamics through decoupling and pole placement. Since it is virtually impossible to find an equivalent bandwidth of the overall system and establish a general eigenvalue requirement for the system, the subsystem dynamics are decoupled through state feedback and the poles are placed simultaneously to realize the desired bandwidths for the three system components. Decoupling and pole placement are also used to design the closed-loop digital system through approximation.

  5. The Annular Suspension and Pointing (ASP) system for space experiments and predicted pointing accuracies

    NASA Technical Reports Server (NTRS)

    Anderson, W. W.; Joshi, S. M.

    1975-01-01

    An annular suspension and pointing system consisting of pointing assemblies for coarse and vernier pointing is described. The first assembly is attached to a carrier spacecraft (e.g., the space shuttle) and consists of an azimuth gimbal and an elevation gimbal which provide 'coarse' pointing. The second or vernier pointing assembly is made up of magnetic actuators of suspension and fine pointing, roll motor segments, and an instrument or experiment mounting plate around which is attached a continuous annular rim similar to that used in the annular momentum control device. The rim provides appropriate magnetic circuits for the actuators and the roll motor segments for any instrument roll position. The results of a study to determine the pointing accuracy of the system in the presence of crew motion disturbances are presented. Typical 3 sigma worst-case errors are found to be of the order of 0.001 arc-second.

  6. Study on needs for a magnetic suspension system operating with a transonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Martindale, W. R.; Butler, R. W.; Starr, R. F.

    1985-01-01

    The U.S. aeronautical industry was surveyed to determine if current and future transonic testing requirements are sufficient to justify continued development work on magnetic suspension and balance systems (MSBS) by NASA. The effort involved preparation of a brief technical description of magnetic suspension and balance systems, design of a survey form asking specific questions about the role of the MSBS in satisfying future testing requirements, selecting nine major aeronautics companies to which the description and survey forms were sent, and visiting the companies and discussing the survey to obtain greater insight to their response to the survey. Evaluation and documentation of the survey responses and recommendations which evolved from the study are presented.

  7. Ride quality evaluation of a vehicle with a planar suspension system

    NASA Astrophysics Data System (ADS)

    Zhu, Jian Jun; Khajepour, Amir; Esmailzadeh, Ebrahim; Kasaiezadeh, Alireza

    2012-03-01

    The longitudinal connection between a chassis and a wheel in a conventional vehicle suspension system is commonly very stiff than the vertical connection. Such a mechanism can efficiently isolate vibrations and absorb shocks in the vertical direction but cannot sufficiently attenuate the impact in the longitudinal direction. In order to overcome such a limitation, a planar suspension system (PSS) with spring-damper struts in both the longitudinal and vertical directions is proposed so that the vibration along any direction in the wheel rotation plane can be isolated. In this paper, the dynamic responses of a vehicle with PSS due to a single bump and random road unevenness are investigated. The ride quality of the vehicle with PSS is evaluated in accordance with ISO 2631. A comparison with that of a similar conventional vehicle is conducted to demonstrate the promising potentials of the PSS in improving the vehicle ride quality.

  8. Alternative Suspension System for Space Shuttle Avionics Shelf

    NASA Technical Reports Server (NTRS)

    Biele, Frank H., III

    2010-01-01

    Engineers working in the Aerospace field under deadlines and strict budgets often miss the opportunity to design something that is considered new or innovative, favoring instead to use the tried-and-true design over those that may, in fact, be more efficient. This thesis examines an electronic equipment stowage shelf suspended from a frame in the cargo bay (mid fuselage) of the United States Space Transportation System (STS), the Space Shuttle, and 3 alternative designs. Four different designs are examined and evaluated. The first design is a conventional truss, representing the tried and true approach. The second is a cable dome type structure consisting of struts and pre-stressed wiring. The third and fourth are double layer tensegrity systems consisting of contiguous struts of the order k=1 and k=2 respectively.

  9. Alternate suspension system for space shuttle avionics shelf

    NASA Astrophysics Data System (ADS)

    Biele, Frank H., III

    This thesis examines an equipment stowage shelf suspended from a frame in the cargo bay (mid fuselage) of the U.S. Space Shuttle, and three alternative designs. The first design is a conventional truss, representing the "tried and true" approach. The second is a cable dome type structure consisting of struts and pre-stressed cables. The third and fourth are double layer tensegrity systems consisting of contiguous struts of the order k=1 and k=2 respectively. The four options are compared to each other with an emphasis placed on weight, size, and approximate cost of each option. Results indicate the 4-Way Double Layer Tensegrity grid utilizing carbon fiber composite cables is the most efficient (lightest weight) tensegrity system, however for this particular application the most cost effective design was proven to be the optimized conventional truss. It was determined that the scale of the structure would have to increase substantially or tensegrity structures complexity must decrease for these alternative systems to compete with conventional designs.

  10. An LQR controller design approach for a Large Gap Magnetic Suspension System (LGMSS)

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.; Schaffner, Philip R.

    1990-01-01

    Two control approaches for a Large Gap Magnetic Suspension System (LGMSS) are investigated and numerical results are presented. The approaches are based on Linear Quadratic Regulator (LQR) control theory and include a nonzero set point regulator with constant disturbance input and an integral feedback regulator. The LGMSS provides five degree of freedom control of a cylindrical suspended element which is composed of permanent magnet material. The magnetic actuators are air core electromagnets mounted in a planar way.

  11. Ion pairs significantly stabilize coiled-coils in the absence of electrolyte.

    PubMed

    Yu, Y; Monera, O D; Hodges, R S; Privalov, P L

    1996-01-26

    We have used a synthetic coiled-coil peptide model system to address the long perplexing issue as to why coiled-coils are in general more stable at acidic pH than at neutral pH. Contrary to the above expectation, our results show that at low ionic strength (10 mM) the coiled-coil was much more stable at neutral pH than at acidic pH against both thermal and urea unfolding, indicating that the Lys(+)-Glu- ions pairs present around the coiled-coil interface at neutral pH contribute significantly to the stability of the coiled-coil. However, while the addition of NaCl had no significant effect on the coiled-coil stability at neutral pH, its stability at acidic pH increased dramatically. The cross-over point between the stability at acidic pH and neutral pH occurred at around 100 mM salt, above which the coiled-coil became more stable at acidic pH, in agreement with published results. Therefore, salt effect, rather than intrinsic property, such as carboxyl-carboxyl hydrogen bonding, causes this coiled-coil to become more stable at acidic pH. The preferential stabilizing effect of salt on the coiled-coil at acidic pH can be best explained in terms of the condensation of anions to the positively charged groups on the coiled-coil, the net density of which increases as glutamic acid residues become protonated in acidic pH.

  12. Final Report: Model interacting particle systems for simulation and macroscopic description of particulate suspensions

    SciTech Connect

    Peter J. Mucha

    2007-08-30

    Suspensions of solid particles in liquids appear in numerous applications, from environmental settings like river silt, to industrial systems of solids transport and water treatment, and biological flows such as blood flow. Despite their importance, much remains unexplained about these complicated systems. Mucha's research aims to improve understanding of basic properties of suspensions through a program of simulating model interacting particle systems with critical evaluation of proposed continuum equations, in close collaboration with experimentalists. Natural to this approach, the original proposal centered around collaboration with studies already conducted in various experimental groups. However, as was detailed in the 2004 progress report, following the first year of this award, a number of the questions from the original proposal were necessarily redirected towards other specific goals because of changes in the research programs of the proposed experimental collaborators. Nevertheless, the modified project goals and the results that followed from those goals maintain close alignment with the main themes of the original proposal, improving efficient simulation and macroscopic modeling of sedimenting and colloidal suspensions. In particular, the main investigations covered under this award have included: (1) Sedimentation instabilities, including the sedimentation analogue of the Rayleigh-Taylor instability (for heavy, particle-laden fluid over lighter, clear fluid). (2) Ageing dynamics of colloidal suspensions at concentrations above the glass transition, using simplified interactions. (3) Stochastic reconstruction of velocity-field dependence for particle image velocimetry (PIV). (4) Stochastic modeling of the near-wall bias in 'nano-PIV'. (5) Distributed Lagrange multiplier simulation of the 'internal splash' of a particle falling through a stable stratified interface. (6) Fundamental study of velocity fluctuations in sedimentation. (7) Parallelization of

  13. Coiled-Coil Design: Updated and Upgraded.

    PubMed

    Woolfson, Derek N

    2017-01-01

    α-Helical coiled coils are ubiquitous protein-folding and protein-interaction domains in which two or more α-helical chains come together to form bundles. Through a combination of bioinformatics analysis of many thousands of natural coiled-coil sequences and structures, plus empirical protein engineering and design studies, there is now a deep understanding of the sequence-to-structure relationships for this class of protein architecture. This has led to considerable success in rational design and what might be termed in biro de novo design of simple coiled coils, which include homo- and hetero-meric parallel dimers, trimers and tetramers. In turn, these provide a toolkit for directing the assembly of both natural proteins and more complex designs in protein engineering, materials science and synthetic biology. Moving on, the increased and improved use of computational design is allowing access to coiled-coil structures that are rare or even not observed in nature, for example α-helical barrels, which comprise five or more α-helices and have central channels into which different functions may be ported. This chapter reviews all of these advances, outlining improvements in our knowledge of the fundamentals of coiled-coil folding and assembly, and highlighting new coiled coil-based materials and applications that this new understanding is opening up. Despite considerable progress, however, challenges remain in coiled-coil design, and the next decade promises to be as productive and exciting as the last.

  14. TEM Systems Design: Using Full Maxwell FDTD Modelling to Study the Transient Response of Custom-madeTx and Rx Coils.

    NASA Astrophysics Data System (ADS)

    Chevalier, A.; Rejiba, F.; Schamper, C.; Thiesson, J.; Hovhannissian, G.

    2016-12-01

    From airborne applications to field scale measurements of Transient Electromagnetic Methods(TEM), an accurate knowledge of the sensitivity of the inductive coil sensors (system response) is aprerequisite to interpret the measured transient magnetic flux density into a subsurface distributionof conductivity. The system response is a term that refers to the cumulative effect of inductive andcapacitive couplings (cross-talks) between each component constituting a TEM apparatus and thenearby conductive structures. As a result, the frequency sensitivity of the voltage coil sensor (Rx)along with the emitted current waveform in the current emitting coil (Tx) are controlled by thegeometry and electronic characteristic of the set-up as well as the near surface electromagneticproperties. During the early development of an innovative airborne TEM solutions (French nationalTEMas project), determining the coil geometries and the impedance matching between all parts ofthe transmission link (electronic parts and coils) for various environmental set-ups, has been a majorissue. In this study, we review the required theoretical framework and propose a versatile numericalmethodology to ease the coil design and impedance matching process while extending ourunderstanding of short-time transient that operates from DC to moderately high frequencies (0 to 20Mhz). We used a full Maxwell equations FDTD model along with a semi-analytical 1D modeler to infercoils emitting and receiving properties, for various coil geometries and site-dependent conditions.Results highlight the influence of the environment on the emitting and sensing properties. Theincreasing effects of cross-talks between the Tx and the Rx coils depending on their size is shown.Strategies regarding the impedance adaptation between the electronical components and the coilsensors are then discussed for different geophysical specifications.

  15. High-lateral-tension abdominoplasty with superficial fascial system suspension.

    PubMed

    Lockwood, T

    1995-09-01

    Modern abdominoplasty techniques were developed in the 1960s. The advent of liposuction has reduced the need for classic abdominoplasty and allowed more aesthetic sculpting of the entire trunk. However, the combination of significant truncal liposuction and classic abdominoplasty is not recommended due to the increased risk of complications. Although the surgical principles of classic abdominoplasty certainly have stood the test of time, they are based on two theoretical assumptions that may be proved to be inaccurate. The first assumption is that wide direct undermining to costal margins is essential for abdominal flap advancement. In fact, discontinuous undermining allows effective loosening of the abdominal flap while preserving vascular perforators. The second inaccurate assumption is that with aging and weight fluctuations (including pregnancy), abdominal skin relaxation occurs primarily in the vertical direction from the xiphoid to the pubis. This is true in the lower abdomen, but in most patients a strong superficial fascial system adherence to the linea alba in the epigastrium limits vertical descent. Epigastric laxity frequently results from a progressive horizontal loosening due to relaxation of the tissue along the lateral trunk. Experience with the lower-body lift procedure has shown that significant lateral truncal skin resection results in epigastric tightening. In these patients, the ideal abdominoplasty pattern would resect as much or more laterally than centrally, leading to more natural abdominal contours. Fifty patients who underwent high-lateral-tension abdominoplasty with and without significant truncal liposuction and other aesthetic procedures were followed for 4 to 16 months. The primary indication for surgery was moderate to severe laxity of abdominal skin and muscle with or without truncal fat deposits. Complication rates were equal to or less than those of historical controls and did not increase with significant adjunctive liposuction

  16. Regenerative magnetorheological dampers for vehicle suspensions

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Zou, Li; Liao, Wei-Hsin

    2015-04-01

    Magnetorheological (MR) dampers are promising for vehicle suspensions, by virtue of their adaptive properties. During the everyday use of vehicles, a lot of energy is wasted due to the energy dissipation by dampers under the road irregularities. On the other hand, extra batteries are required for the current MR damper systems. To reduce the energy waste and get rid of the dependence on extra batteries, in this paper, regenerative MR dampers are proposed for vehicle suspensions, which integrate energy harvesting and controllable damping functions. The wasted vibration energy can be converted into electrical energy and power the MR damper coil. A regenerative MR damper for vehicle suspensions is developed. Damping force and power generation characteristics of the regenerative MR damper were modeled and analyzed. Then the damper is applied to a 2 DOF suspension system for system simulation under various road conditions. Simulation results show that riding comfort can be significantly improved, while harvesting energy for other use in addition to supply power for the controlled MR damper.

  17. Robust fault-tolerant H∞ control of active suspension systems with finite-frequency constraint

    NASA Astrophysics Data System (ADS)

    Wang, Rongrong; Jing, Hui; Karimi, Hamid Reza; Chen, Nan

    2015-10-01

    In this paper, the robust fault-tolerant (FT) H∞ control problem of active suspension systems with finite-frequency constraint is investigated. A full-car model is employed in the controller design such that the heave, pitch and roll motions can be simultaneously controlled. Both the actuator faults and external disturbances are considered in the controller synthesis. As the human body is more sensitive to the vertical vibration in 4-8 Hz, robust H∞ control with this finite-frequency constraint is designed. Other performances such as suspension deflection and actuator saturation are also considered. As some of the states such as the sprung mass pitch and roll angles are hard to measure, a robust H∞ dynamic output-feedback controller with fault tolerant ability is proposed. Simulation results show the performance of the proposed controller.

  18. Soft-coupling suspension system for an intradural spinal cord stimulator: Biophysical performance characteristics

    NASA Astrophysics Data System (ADS)

    Oya, H.; Safayi, S.; Jeffery, N. D.; Viljoen, S.; Reddy, C. G.; Dalm, B. D.; Kanwal, J. K.; Gillies, G. T.; Howard, M. A.

    2013-10-01

    We have characterized the mechanical compliance of an improved version of the suspension system used to position the electrode-bearing membrane of an intradural neuromodulator on the dorsal pial surface of the spinal cord. Over the compression span of 5 mm, it exhibited a restoring force of 2.4 μN μm-1 and a mean pressure of 0.5 mm Hg (=66 Pa) on the surface below it, well within the range of normal intrathecal pressures. We have implanted prototype devices employing this suspension and a novel device fixation technique in a chronic ovine model of spinal cord stimulation and found that it maintains stable contact at the electrode-pia interface without lead fracture, as determined by measurement of the inter-contact impedances.

  19. Magnet Coil Shorted Turn Detector

    SciTech Connect

    Dinkel, J.A.; Biggs, J.E.

    1994-03-01

    The Magnet Coil Shorted Turn Detector has been developed to facilitate the location of shorted turns in magnet coils. Finding these shorted turns is necessary to determine failure modes that are a necessary step in developing future production techniques. Up to this point, coils with shorted turns had the insulation burned off without the fault having been located. This disassembly process destroyed any chance of being able to find the fault. In order to maintain a flux balance in a coupled system such as a magnet coil, the current in a shorted turn must be opposed to the incident current. If the direction of the current in each conductor can be measured relative to the incident current, then the exact location of the short can be determined. In this device, an AC voltage is applied to the magnet under test. A small hand held B-dot pickup coil monitors the magnetic field produced by current in the individual magnet conductors. The relative phase of this pickup coil voltage is compared to a reference signal derived from the input current to detect a current reversal as the B-dot pickup coil is swept over the conductors of the coil under test. This technique however, is limited to only those conductors that are accessible to the hand held probe.

  20. PARTITION EFFICIENCY OF NEWLY DESIGNED LOCULAR MULTILAYER COIL FOR COUNTERCURRENT CHROMATOGRAPHIC SEPARATION OF PROTEINS USING SMALL-SCALE CROSS-AXIS COIL PLANET CENTRIFUGE WITH AQUEOUS-AQUEOUS POLYMER PHASE SYSTEMS.

    PubMed

    Shinomiya, Kazufusa; Ito, Yoichiro

    2009-01-01

    Countercurrent chromatographic performance of the locular multilayer coil separation column newly designed in our laboratory was evaluated in terms of theoretical plate number, peak resolution and retention of the stationary phase in protein separation with an aqueous polymer phase system using the small-scale cross-axis coil planet centrifuge (X-axis CPC) fabricated in our laboratory. The locular column was made from 1.0 mm I.D., 2.0 mm O.D. or 1.5 mm I.D., 2.5 mm O.D. PTFE tubing compressed with a pair of hemostat at 2 or 4 cm intervals. The protein separation was performed using a set of stable proteins including cytochrome C, myoglobin and lysozyme with the 12.5% (w/w) polyethylene glycol 1000 and 12.5% (w/w) dibasic potassium phosphate system under 1000 rpm of column revolution. The 1.5 mm I.D., 2.5 mm O.D. locular tubing compressed at 2 cm intervals yielded better partition efficiencies than the non-clamped tubing using both lower and upper mobile phases with satisfactory retention of the stationary phase. The overall results suggest that the newly designed locular multilayer coil is useful to the preparative separation of proteins with aqueous-aqueous polymer phase system using our small-scale X-axis CPC.

  1. Drag measurements on a body of revolution in Langley's 13-inch Magnetic Suspension and Balance System

    NASA Technical Reports Server (NTRS)

    Dress, David A.

    1988-01-01

    NASA Langley's 13-inch Magnetic Suspension and Balance System (MSBS) has been used to conduct low-speed wind tunnel drag force measurements on a laminar-flow body-of-revolution free of support system interference, in order to verify the drag force measurement capabilities of the MSBS. The drag force calibrations and wind-on repeatability data obtained have verified the design capabilities for this system. A drag-prediction code has been used to assess the MSBS's usefulness in body drag estimation.

  2. Nonlinear analysis and performance evaluation of the Annular Suspension and Pointing System (ASPS)

    NASA Technical Reports Server (NTRS)

    Joshi, S. M.

    1978-01-01

    The Annular Suspension and Pointing System (ASPS) can provide high accurate fine pointing for a variety of solar-, stellar-, and Earth-viewing scientific instruments during space shuttle orbital missions. In this report, a detailed nonlinear mathematical model is developed for the ASPS/Space Shuttle system. The equations are augmented with nonlinear models of components such as magnetic actuators and gimbal torquers. Control systems and payload attitude state estimators are designed in order to obtain satisfactory pointing performance, and statistical pointing performance is predicted in the presence of measurement noise and disturbances.

  3. Drag measurements on a body of revolution in Langley's 13-inch Magnetic Suspension and Balance System

    NASA Technical Reports Server (NTRS)

    Dress, David A.

    1988-01-01

    NASA Langley's 13-inch Magnetic Suspension and Balance System (MSBS) has been used to conduct low-speed wind tunnel drag force measurements on a laminar-flow body-of-revolution free of support system interference, in order to verify the drag force measurement capabilities of the MSBS. The drag force calibrations and wind-on repeatability data obtained have verified the design capabilities for this system. A drag-prediction code has been used to assess the MSBS's usefulness in body drag estimation.

  4. Implementation of a decoupled controller for a magnetic suspension system using electromagnets mounted in a planar array

    NASA Technical Reports Server (NTRS)

    Cox, D. E.; Groom, N. J.

    1994-01-01

    An implementation of a decoupled, single-input/single-output control approach for a large angle magnetic suspension test fixture is described. Numerical and experimental results are presented. The experimental system is a laboratory model large gap magnetic suspension system which provides five degree-of-freedom control of a cylindrical suspended element. The suspended element contains a core composed of permanent magnet material and is levitated above five electromagnets mounted in a planar array.

  5. A preparative suspension culture system permitting quantitation of anchorage-independent growth by direct radiolabeling of cellular DNA.

    PubMed

    Assoian, R K; Boardman, L A; Drosinos, S

    1989-02-15

    We have developed a hybrid methylcellulose/agar suspension culture system which permits long-term colony formation of transformed mesenchymal cells. In contrast to traditional agar suspensions, our system allows for recovery of cells and direct biochemical analysis of anchorage-independent growth. The ability to readily radiolabel cellular macromolecules in these preparative cultures permits a quantitative and objective analysis of colony formation by incorporation of [3H]thymidine into newly synthesized DNA.

  6. Analytical determination of space station response to crew motion and design of suspension system for microgravity experiments

    NASA Technical Reports Server (NTRS)

    Liu, Frank C.

    1987-01-01

    The objective of this investigation is to make analytical determination of the acceleration produced by crew motion in an orbiting space station and define design parameters for the suspension system of microgravity experiments. A simple structural model for simulation of the IOC space station is proposed. Mathematical formulation of this model provides the engineers a simple and direct tool for designing an effective suspension system.

  7. Analytical determination of space station response to crew motion and design of suspension system for microgravity experiments

    NASA Technical Reports Server (NTRS)

    Liu, F. C.

    1986-01-01

    The objective of this investigation is to make analytical determination of the acceleration produced by crew motion in an orbiting space station and define design parameters for the suspension system of microgravity experiments. A simple structural model for simulation of the IOC space station is proposed. Mathematical formulation of this model provides the engineers a simple and direct tool for designing an effective suspension system.

  8. The Effects of Suction and Pin/Lock Suspension Systems on Transtibial Amputees’ Gait Performance

    PubMed Central

    Gholizadeh, Hossein; Abu Osman, Noor Azuan; Eshraghi, Arezoo; Ali, Sadeeq

    2014-01-01

    Background The suction sockets that are commonly prescribed for transtibial amputees are believed to provide a better suspension than the pin/lock systems. Nevertheless, their effect on amputees’ gait performance has not yet been fully investigated. The main intention of this study was to understand the potential effects of the Seal-in (suction) and the Dermo (pin/lock) suspension systems on amputees’ gait performance. Methodology/Principal Findings Ten unilateral transtibial amputees participated in this prospective study, and two prostheses were fabricated for each of them. A three-dimensional motion analysis system was used to evaluate the temporal-spatial, kinematics and kinetics variables during normal walking. We also asked the participants to complete some part of Prosthesis Evaluation Questionnaire (PEQ) regarding their satisfaction and problems with both systems. The results revealed that there was more symmetry in temporal-spatial parameters between the prosthetic and sound limbs using the suction system. However, the difference between two systems was not significant (p<0.05). Evaluation of kinetic data and the subjects’ feedback showed that the participants had more confidence using the suction socket and the sockets were more fit for walking. Nevertheless, the participants had more complaints with this system due to the difficulty in donning and doffing. Conclusion It can be concluded that even though the suction socket could create better suspension, fit, and gait performance, overall satisfaction was higher with the pin/lock system due to easy donning and doffing of the prosthesis. Trial Registration irct.ir IRCT2014012816395N1 PMID:24827560

  9. A Parallel Coiled-Coil Tetramer with Offset Helices

    SciTech Connect

    Liu,J.; Deng, Y.; Zheng, Q.; Cheng, C.; Kallenbach, N.; Lu, M.

    2006-01-01

    Specific helix-helix interactions are fundamental in assembling the native state of proteins and in protein-protein interfaces. Coiled coils afford a unique model system for elucidating principles of molecular recognition between {alpha} helices. The coiled-coil fold is specified by a characteristic seven amino acid repeat containing hydrophobic residues at the first (a) and fourth (d) positions. Nonpolar side chains spaced three and four residues apart are referred to as the 3-4 hydrophobic repeat. The presence of apolar amino acids at the e or g positions (corresponding to a 3-3-1 hydrophobic repeat) can provide new possibilities for close-packing of {alpha}-helices that includes examples such as the lac repressor tetramerization domain. Here we demonstrate that an unprecedented coiled-coil interface results from replacement of three charged residues at the e positions in the dimeric GCN4 leucine zipper by nonpolar valine side chains. Equilibrium circular dichroism and analytical ultracentrifugation studies indicate that the valine-containing mutant forms a discrete {alpha}-helical tetramer with a significantly higher stability than the parent leucine-zipper molecule. The 1.35 {angstrom} resolution crystal structure of the tetramer reveals a parallel four-stranded coiled coil with a three-residue interhelical offset. The local packing geometry of the three hydrophobic positions in the tetramer conformation is completely different from that seen in classical tetrameric structures yet bears resemblance to that in three-stranded coiled coils. These studies demonstrate that distinct van der Waals interactions beyond the a and d side chains can generate a diverse set of helix-helix interfaces and three-dimensional supercoil structures.

  10. Suppressing local hot spots due to eddy currents in magnetic coil systems

    NASA Astrophysics Data System (ADS)

    Yao, Zhen; Shojinaga, Aaron; Wu, Yong; Shvartsman, Shmaryu; Eagan, Timothy; Chmielewski, Thomas; Brown, Robert

    2011-03-01

    A particular goal in magnetic field applications is to avoid eddy current heating in coils and shields. It is important, in MRI, for example, to avoid hot spots near the patient to be imaged as well as in the vicinity of soldering joints. We develop effective analytical formulas for the eddy current behavior of sources close to surrounding conductors, we verify these via numerical simulations, and we make successful comparisons to corresponding experimental temperature distributions. Optimized patterns of incisions made in the conductors are discovered for addressing particularly troublesome heating locations. The criteria include the need to minimize the number and length of the cuts. Theory and experiment are in agreement on the efficacy of this method for reducing steady-state temperatures. An example of results in the practical design of commercial coils and shields is that a single cut parallel to the long edge of rectangular conductors reduces the temperatures much more than making multiple cuts parallel to the short edge. Supported by Ohio Third Frontier Program

  11. System identification of the Large-Angle Magnetic Suspension Test Fixture (LAMSTF)

    NASA Technical Reports Server (NTRS)

    Huang, Jen-Kuang

    1994-01-01

    The Large-Angle Magnetic Suspension Test Fixture (LAMSTF), a laboratory-scale research project to demonstrate the magnetic suspension of objects over wide ranges of attitudes, has been developed. This system represents a scaled model of a planned Large-Gap Magnetic Suspension System (LGMSS). The LAMSTF consists of a small cylindrical permanent magnet suspended element which is levitated above a planar array of five electromagnets mounted in a circular configuration. The cylinder is a rigid body and can be controlled to move in five independent degrees of freedom. Six position variables are sensed indirectly by using infrared light-emitting diodes and light-receiving phototransistors. The motion of the suspended cylinder is in general nonlinear and hence only the linear, time-invariant perturbed motion about an equilibrium state is considered. One of the main challenges in this project is the control of the suspended element over a wide range of orientations. An accurate dynamic model plays an essential role in controller design. The analytical model is first derived and open-loop characteristics discussed. The system is shown to be highly unstable and requires feedback control for system identification. Projection filters are first proposed to identify the state space model from closed-loop input/output test data in the time domain. This method is then extended to identify linear systems from the frequency test data. A canonical transformation matrix is also derived to transform the identified state space model into the physical coordinate. The LAMSTF system is stabilized by using a linear quadratic regulator (LQR) feedback controller for closed-loop identification. The rate information is obtained by calculating the back difference of the sensed position signals. Only the closed-loop random input/output data are recorded. Preliminary results from numerical simulations demonstrate that the identified system model is fairly accurate from either time domain or

  12. RF Head Coil Design with Improved RF Magnetic Near-Fields Uniformity for Magnetic Resonance Imaging (MRI) Systems.

    PubMed

    Sohn, Sung-Min; DelaBarre, Lance; Gopinath, Anand; Vaughan, John Thomas

    2014-08-01

    Higher magnetic field strength in magnetic resonance imaging (MRI) systems offers higher signal-to-noise ratio (SNR), contrast, and spatial resolution in MR images. However, the wavelength in ultra-high fields (7 tesla and beyond) becomes shorter than the human body at the Larmor frequency with increasing static magnetic field (B0) of MRI system. At short wavelengths, interference effect appears resulting in non- uniformity of the RF magnetic near-field (B1) over the subject and MR images may have spatially anomalous contrast. The B1 near-field generated by the transverse electromagnetic (TEM) RF coil's microstrip line element has a maximum near the center of its length and falls off towards both ends. In this study, a double trapezoidal shaped microstrip transmission line element is proposed to obtain uniform B1 field distribution by gradual impedance variation. Two multi-channel RF head coils with uniform and trapezoidal shape elements were built and tested with a phantom at 7T MRI scanner for comparison. The simulation and experimental results show stronger and more uniform B1(+) near-field with the trapezoidal shape.

  13. Protein detection by Western blot via coiled-coil interactions.

    PubMed

    Boucher, Cyril; St-Laurent, Gilles; Jolicoeur, Mario; Crescenzo, Gregory De; Durocher, Yves

    2010-04-01

    We propose an approach for the detection of proteins by Western blot that takes advantage of the high-affinity interaction occurring between two de novo designed peptides, the E and K coils. As a model system, K coil-tagged epidermal growth factor (EGF) was revealed with secreted alkaline phosphatase (SeAP) tagged with E coil (SeAP-Ecoil) as well as with biotinylated E coil. In that respect, we first produced purified SeAP-Ecoil and verified its ability to interact with K coil peptides by surface plasmon resonance biosensing. We demonstrated that protein detection with Ecoil-biotin was more specific than with SeAP-Ecoil. We then showed that our approach is as sensitive as conventional detection strategies relying on nickel-nitrilotriacetic acid-horseradish peroxidase (Ni-NTA-HRP), anti-His-HRP, or anti-EGF. Altogether, our results indicate that the E/K coiled-coil system is a good alternative for protein detection by Western blot. Crown Copyright 2009. Published by Elsevier Inc. All rights reserved.

  14. Coiled tubing - Operations and services

    SciTech Connect

    Gronseth, J.M. )

    1993-04-01

    Drilling with a continuous (rather than jointed) drill string is an old concept that is gaining new attention as a result of recent advances made in coiled tubing and drilling technology. The development of larger diameter, reliable, high-strength coiled tubing and smaller diameter, positive displacement motors, orienting tools, surveying systems and fixed cutting drill bits have given drilling with a continuous drill string a capability that was previously unattainable. Like its many other uses, (e.g., squeeze cementing, wellbore cleanouts, flow initiation, logging) the continuity of coiled tubing gives it several advantages over conventional drill strings. These include: drilling underbalanced safely, significantly reduced trip time, continuous circulation, smaller surface requirements. Coiled tubing drilling operations have smaller surface lease requirements than most conventional rigs due to the smaller footprint of the coiled tubing unit and associated equipment. Current coiled tubing drilling operations have the following limitations: conventional rig assistance is required for well preparation; conventional rigs must assist in running long protective and production casing strings or liners; hole sizes are smaller; working depth capabilities are shallower, coiled tubing life is less. This paper goes on to discuss the history of continuous drill strings and includes information on tubing units, circulating systems, drilling fluids, well control systems, downhole tools, orientation tools, and bottomhole assemblies. It then gives a cost comparison and an application of this type of drilling.

  15. Extensions of suspension systems to measure effects of hypokinesia/hypodynamia and antiorthostasis in rats

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, J. M.

    1984-01-01

    Suspension systems are used to simulate hypokinetic/hypodynamic (H/H) and anitorthostatic (AO) responses seen under conditions of weightlessness. Growing rats in H/H suspension with unloaded hindlimbs for one and two weeks respond with muscle atrophy and increased excretion of nitrogenous end products such as urea, NH3 and 3 methyl histidine. Since muscle is in a dynamic state of synthesis and breakdown of protein, relationships between protein, RNA and DNA contents in the four muscles which reflect weight bearing and non-weight bearing functions were assessed. Protein and RNA progressively decreased over a one and two week period of H/H suspension: soleus gastrocnemius=plantaris EDL. Concommitant analysis of DNA contents showed there were no changes. The interpretation was that protein synthesis was slowed during H/H. As with muscle mass, protein and RNA levels recovered rapidly after removal from H/H. The AO rats (which are also H/H) respond with diuresis, natriuresis and kaliuresis in a manner comparable to responses seen when thoracic blood vessels are volume loaded.

  16. [Readaptation processes in the calcitonin-producing system of the rat's thyroid following 30-day suspension].

    PubMed

    Loginov, V I

    2007-01-01

    Immunocytochemical and cytomorphological studies of ca/citonin-producing cells (C-cells) in the thyroid of rats were conducted on days 0, 2, 8, 14, 30 and 60 of readaptation from 30-d tail-suspension. It was shown that suspension reduced the C-cell pool by 35% and size of C-cell nuclei and cytoplasm by 15% and 12%, respectively. On the contrary, the amount of inactive cells within the total pool increased by 33% at the expense of actively secreting cells (17% loss) and secret depot cells (13% loss). The data suggest a dramatic inhibition of the C-cell functional activity due to insufficient loading of the musculoskeletal system. In 48 hrs. after suspension, biosynthesis in the C-cell population was obviously stimulated as indicated by the increase of nuclei size by 11%. The total C-cell population as well as the proportion of C-cell functional varieties regained normal values by day 8 of readaptation; however, nuclear size remained abnormal which could be consequence of elevated biosynthetic activity in that period. Investigations of morphometric indices of the C-cell functional activity fulfilled on days 14 and 30 of readaptation failed to detect any differences between the suspended rats and their controls. Investigations performed on days 30 and 60 of readaptation showed increases in C-cell population resulting from daily and total body mass gain.

  17. Muscle Activation during Push-Ups with Different Suspension Training Systems

    PubMed Central

    Calatayud, Joaquin; Borreani, Sebastien; Colado, Juan C.; Martín, Fernando F; Rogers, Michael E.; Behm, David G.; Andersen, Lars L.

    2014-01-01

    The purpose of this study was to analyze upper extremity and core muscle activation when performing push-ups with different suspension devices. Young fit male university students (n = 29) performed 3 push-ups each with 4 different suspension systems. Push-up speed was controlled using a metronome and testing order was randomized. Average amplitude of the electromyographic root mean square of Triceps Brachii, Upper Trapezius, Anterior Deltoid, Clavicular Pectoralis, Rectus Abdominis, Rectus Femoris, and Lumbar Erector Spinae was recorded. Electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC). Electromyographic data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc. Based upon global arithmetic mean of all muscles analyzed, the suspended push-up with a pulley system provided the greatest activity (37.76% of MVIC; p < 0.001). Individually, the suspended push-up with a pulley system also provided the greatest triceps brachii, upper trapezius, rectus femoris and erector lumbar spinae muscle activation. In contrast, more stable conditions seem more appropriate for pectoralis major and anterior deltoid muscles. Independent of the type of design, all suspension systems were especially effective training tools for reaching high levels of rectus abdominis activation. Key Points Compared with standard push-ups on the floor, suspended push-ups increase core muscle activation. A one-anchor system with a pulley is the best option to increase TRICEP, TRAPS, LUMB and FEM muscle activity. More stable conditions such as the standard push-up or a parallel band system provide greater increases in DELT and PEC muscle activation. A suspended push-up is an effective method to achieve high muscle activity levels in the ABS. PMID:25177174

  18. Muscle Activation during Push-Ups with Different Suspension Training Systems.

    PubMed

    Calatayud, Joaquin; Borreani, Sebastien; Colado, Juan C; Martín, Fernando F; Rogers, Michael E; Behm, David G; Andersen, Lars L

    2014-09-01

    The purpose of this study was to analyze upper extremity and core muscle activation when performing push-ups with different suspension devices. Young fit male university students (n = 29) performed 3 push-ups each with 4 different suspension systems. Push-up speed was controlled using a metronome and testing order was randomized. Average amplitude of the electromyographic root mean square of Triceps Brachii, Upper Trapezius, Anterior Deltoid, Clavicular Pectoralis, Rectus Abdominis, Rectus Femoris, and Lumbar Erector Spinae was recorded. Electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC). Electromyographic data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc. Based upon global arithmetic mean of all muscles analyzed, the suspended push-up with a pulley system provided the greatest activity (37.76% of MVIC; p < 0.001). Individually, the suspended push-up with a pulley system also provided the greatest triceps brachii, upper trapezius, rectus femoris and erector lumbar spinae muscle activation. In contrast, more stable conditions seem more appropriate for pectoralis major and anterior deltoid muscles. Independent of the type of design, all suspension systems were especially effective training tools for reaching high levels of rectus abdominis activation. Key PointsCompared with standard push-ups on the floor, suspended push-ups increase core muscle activation.A one-anchor system with a pulley is the best option to increase TRICEP, TRAPS, LUMB and FEM muscle activity.More stable conditions such as the standard push-up or a parallel band system provide greater increases in DELT and PEC muscle activation.A suspended push-up is an effective method to achieve high muscle activity levels in the ABS.

  19. Non-linear dynamic modeling of an automobile hydraulic active suspension system

    NASA Astrophysics Data System (ADS)

    Mrad, R. Ben; Levitt, J. A.; Fassois, S. D.

    1994-09-01

    Motived by the strong need for realistically describing the dynamical behaviour of automotive systems through adequate mathematical models, a computer-stimulation-suitable non-linear quarter-car model of a hydraulic active suspension system is developed. Unlike previously available linear models characterised by idealised actuator and component behaviour, the developed model accounts for the dynamics of the main system components, including the suspension bushing, pump, accumulator, power and bypass valves, and hydraulic actuator, while also incorporating preliminary versions of the system controllers. Significant system characteristics, such as non-linear pressure-flow relationships, fluid compressibility, pump and valve non-linearities, leakages, as well as Coulomb friction, are also explicitly accounted for, and the underpinning assumptions are discussed. Simulation results obtained by exercising the model provide insight into the system behavior, illustrate the importance of the actuator/component dynamics and their associated non-linearities and reveal the inadequacy of the idealised linear models in capturing the system behaviour, demonstrate specific effects of valve leakage and fluid bulk modulus, are in qualitative agreement with experimental measurements, and stress the need for proper control law design and tuning. The developed model is particularly suitable for analysis, design, control law optimisation, and diagnostic strategies development.

  20. Signal frequency based self-tuning fuzzy controller for semi-active suspension system.

    PubMed

    Sun, Tao; Huang, Zhen-Yu; Chen, Da-Yue; Tang, Lei

    2003-01-01

    A new kind of fuzzy control scheme, based on the identification of the signal's main frequency and the behavior of the ER damper, is proposed to control the semi-active suspension system. This method adjusts the fuzzy controller to achieve the best isolation effect by analyzing the main frequency's characters and inspecting the change of system parameters. The input of the fuzzy controller is the main frequency and the optimal damping ratio is the output. Simulation results indicated that the proposed control method is very effective in isolating the vibration.

  1. Frequency of Morning Ketosis After Overnight Insulin Suspension Using an Automated Nocturnal Predictive Low Glucose Suspend System

    PubMed Central

    Beck, Roy W.; Raghinaru, Dan; Wadwa, R. Paul; Chase, H. Peter; Maahs, David M.; Buckingham, Bruce A.

    2014-01-01

    OBJECTIVE To assess the effect of overnight insulin pump suspension in an automated predictive low glucose suspend system on morning blood glucose and ketone levels in an attempt to determine whether routine measurement of ketone levels is useful when a closed-loop system that suspends insulin delivery overnight is being used. RESEARCH DESIGN AND METHODS Data from an in-home randomized trial of 45 individuals with type 1 diabetes (age range 15–45 years) were analyzed, evaluating an automated predictive low glucose pump suspension system in which blood glucose, blood ketone, and urine ketone levels were measured on 1,954 mornings. RESULTS One or more pump suspensions occurred during 744 of the 977 intervention nights (76%). The morning blood ketone level was ≥0.6 mmol/L after 11 of the 744 nights (1.5%) during which a pump suspension occurred and 2 of the 233 nights (0.9%) during which there was no suspension compared with 11 of 977 control nights (1.1%). The morning blood ketone level was ≥0.6 mmol/L after only 2 of 159 nights (1.3%) with a pump suspension exceeding 2 h. Morning fasting blood glucose level was not a good predictor of the presence of blood ketones. CONCLUSIONS Routine measurement of blood or urine ketones during use of an automated pump suspension system using continuous glucose monitoring, whether threshold based or predictive, is not necessary. Recommendations for checking ketone levels should be no different when a patient is using a system with automated insulin suspension than it is for conventional diabetes self-management. PMID:24757229

  2. Hysteresis-induced bifurcation and chaos in a magneto-rheological suspension system under external excitation

    NASA Astrophysics Data System (ADS)

    Hailong, Zhang; Enrong, Wang; Fuhong, Min; Ning, Zhang

    2016-03-01

    The magneto-rheological damper (MRD) is a promising device used in vehicle semi-active suspension systems, for its continuous adjustable damping output. However, the innate nonlinear hysteresis characteristic of MRD may cause the nonlinear behaviors. In this work, a two-degree-of-freedom (2-DOF) MR suspension system was established first, by employing the modified Bouc-Wen force-velocity (F-v) hysteretic model. The nonlinear dynamic response of the system was investigated under the external excitation of single-frequency harmonic and bandwidth-limited stochastic road surface. The largest Lyapunov exponent (LLE) was used to detect the chaotic area of the frequency and amplitude of harmonic excitation, and the bifurcation diagrams, time histories, phase portraits, and power spectrum density (PSD) diagrams were used to reveal the dynamic evolution process in detail. Moreover, the LLE and Kolmogorov entropy (K entropy) were used to identify whether the system response was random or chaotic under stochastic road surface. The results demonstrated that the complex dynamical behaviors occur under different external excitation conditions. The oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations, and chaotic oscillations was observed in detail. The chaotic regions revealed that chaotic motions may appear in conditions of mid-low frequency and large amplitude, as well as small amplitude and all frequency. The obtained parameter regions where the chaotic motions may appear are useful for design of structural parameters of the vibration isolation, and the optimization of control strategy for MR suspension system. Projects supported by the National Natural Science Foundation of China (Grant Nos. 51475246, 51277098, and 51075215), the Research Innovation Program for College Graduates of Jiangsu Province China (Grant No. KYLX15 0725), and the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20131402).

  3. Design and optimization of voice coil actuator for six degree of freedom active vibration isolation system using Halbach magnet array.

    PubMed

    Kim, MyeongHyeon; Kim, Hyunchang; Gweon, Dae-Gab

    2012-10-01

    This paper describes the design, modeling, optimization, and validation of an active vibration isolation system using a voice coil motor. The active vibration isolating method was constructed with a passive isolator and an active isolator. A spring was used for passive isolating; an actuator was used for active isolating. The proposed active vibration isolation system (AVIS) can isolate disturbances for many kinds of instruments. Until now, developed AVIS were able to isolate a six degree-of-freedom disturbance effectively. This paper proposes the realization of such a six degree-of-freedom active vibration isolation system that can work as a bench top device for precision measuring machines such as atomic force microscope, scanning probe microscope, etc.

  4. Dynamic stabilization of a bistable suspension system attached to a flexible host structure for operational safety enhancement

    NASA Astrophysics Data System (ADS)

    Yang, Kai; Harne, R. L.; Wang, K. W.; Huang, Hai

    2014-12-01

    In engineering applications, a suspension system may be attached to a flexible host structure, e.g. spacecraft truss, to provide vibration isolation for sensitive instrumentation, where the suspension and host structure dynamics are strongly coupled. For linear suspensions, a resonance normally occurs adjacent to the roll-off frequency band, which significantly and detrimentally amplifies vibration transmission. To avoid the adverse resonance for operational safety enhancement, this research proposes a nonlinear bistable suspension and evaluates its performance when attached to a flexible host structure. Dynamic models of the bistable and comparable linear suspensions attached to the host structure are formulated, and steady-state responses are predicted using analytical and numerical methods. Results show that the bistable suspension can eliminate the harmful resonance via a dynamic stabilization phenomenon, and simultaneously retains the favorable isolation performance in the roll-off bandwidth as compared to the linear suspension. Series of experimental investigations support the analytical and numerical findings and help define design guidelines for operational safety improvement.

  5. Fuzzy chaos control for vehicle lateral dynamics based on active suspension system

    NASA Astrophysics Data System (ADS)

    Huang, Chen; Chen, Long; Jiang, Haobin; Yuan, Chaochun; Xia, Tian

    2014-07-01

    The existing research of the active suspension system (ASS) mainly focuses on the different evaluation indexes and control strategies. Among the different components, the nonlinear characteristics of practical systems and control are usually not considered for vehicle lateral dynamics. But the vehicle model has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, the nonlinear dynamic model of lateral system is considered and also the adaptive neural network of tire is introduced. By nonlinear analysis methods, such as the bifurcation diagram and Lyapunov exponent, it has shown that the lateral dynamics exhibits complicated motions with the forward speed. Then, a fuzzy control method is applied to the lateral system aiming to convert chaos into periodic motion using the linear-state feedback of an available lateral force with changing tire load. Finally, the rapid control prototyping is built to conduct the real vehicle test. By comparison of time response diagram, phase portraits and Lyapunov exponents at different work conditions, the results on step input and S-shaped road indicate that the slip angle and yaw velocity of lateral dynamics enter into stable domain and the results of test are consistent to the simulation and verified the correctness of simulation. And the Lyapunov exponents of the closed-loop system are becoming from positive to negative. This research proposes a fuzzy control method which has sufficient suppress chaotic motions as an effective active suspension system.

  6. Compact vibration isolation and suspension for Australian International Gravitational Observatory: local control system.

    PubMed

    Dumas, Jean-Charles; Barriga, Pablo; Zhao, Chunnong; Ju, Li; Blair, David G

    2009-11-01

    High performance vibration isolators are required for ground based gravitational wave detectors. To attain very high performance at low frequencies we have developed multistage isolators for the proposed Australian International Gravitational Observatory detector in Australia. New concepts in vibration isolation including self-damping, Euler springs, LaCoste springs, Roberts linkages, and double preisolation require novel sensors and actuators. Double preisolation enables internal feedback to be used to suppress low frequency seismic noise. Multidegree of freedom control systems are required to attain high performance. Here we describe the control components and control systems used to control all degrees of freedom. Feedback forces are injected at the preisolation stages and at the penultimate suspension stage. There is no direct actuation on test masses. A digital local control system hosted on a digital signal processor maintains alignment and position, corrects drifts, and damps the low frequency linear and torsional modes without exciting the very high Q-factor test mass suspension. The control system maintains an optical cavity locked to a laser with a high duty cycle even in the absence of an autoalignment system. An accompanying paper presents the mechanics of the system, and the optical cavity used to determine isolation performance. A feedback method is presented, which is expected to improve the residual motion at 1 Hz by more than one order of magnitude.

  7. Toroidal field coil design concept and structural support system for CTHR

    SciTech Connect

    Chianese, R. B.; Kelly, J. L.; Ruck, G. W.

    1980-09-01

    The CTHR conceptual design consists of a magnetically confined (tokamak) fusion reactor fitted with a fertile uranium blanket. The fusion driver concept was based on an ignited plasma. All concepts and parameters were selected on the basis that technical feasibility would be achieved by 1995 to assure a viable commercial operation in the early to mid-21st century. The reactor was designed to achieve good fissile fuel production, with electricity production being a second order priority. However, the resulting concepts that evolved were all excellent power producers which significantly improved the economic performance. The subsystems discussed in the following paragraphs provide a background of the application for the TF coil design described in this report.

  8. Inductively coupled wireless RF coil arrays.

    PubMed

    Bulumulla, S B; Fiveland, E; Park, K J; Foo, T K; Hardy, C J

    2015-04-01

    As the number of coils increases in multi-channel MRI receiver-coil arrays, RF cables and connectors become increasingly bulky and heavy, degrading patient comfort and slowing workflow. Inductive coupling of signals provides an attractive "wireless" approach, with the potential to reduce coil weight and cost while simplifying patient setup. In this work, multi-channel inductively coupled anterior arrays were developed and characterized for 1.5T imaging. These comprised MR receiver coils inductively (or "wirelessly") linked to secondary or "sniffer" coils whose outputs were transmitted via preamps to the MR system cabinet. The induced currents in the imaging coils were blocked by passive diode circuits during RF transmit. The imaging arrays were totally passive, obviating the need to deliver power to the coils, and providing lightweight, untethered signal reception with easily positioned coils. Single-shot fast spin echo images were acquired from 5 volunteers using a 7-element inductively coupled coil array and a conventionally cabled 7-element coil array of identical geometry, with the inductively-coupled array showing a relative signal-to-noise ratio of 0.86 +/- 0.07. The concept was extended to a larger 9-element coil array to demonstrate the effect of coil element size on signal transfer and RF-transmit blocking.

  9. N@a and N@d: Oligomer and Partner Specification by Asparagine in Coiled-Coil Interfaces.

    PubMed

    Fletcher, Jordan M; Bartlett, Gail J; Boyle, Aimee L; Danon, Jonathan J; Rush, Laura E; Lupas, Andrei N; Woolfson, Derek N

    2017-02-17

    The α-helical coiled coil is one of the best-studied protein-protein interaction motifs. As a result, sequence-to-structure relationships are available for the prediction of natural coiled-coil sequences and the de novo design of new ones. However, coiled coils adopt a wide range of oligomeric states and topologies, and our understanding of the specification of these and the discrimination between them remains incomplete. Gaps in our knowledge assume more importance as coiled coils are used increasingly to construct biomimetic systems of higher complexity; for this, coiled-coil components need to be robust, orthogonal, and transferable between contexts. Here, we explore how the polar side chain asparagine (Asn, N) is tolerated within otherwise hydrophobic helix-helix interfaces of coiled coils. The long-held view is that Asn placed at certain sites of the coiled-coil sequence repeat selects one oligomer state over others, which is rationalized by the ability of the side chain to make hydrogen bonds, or interactions with chelated ions within the coiled-coil interior of the favored state. We test this with experiments on de novo peptide sequences traditionally considered as directing parallel dimers and trimers, and more widely through bioinformatics analysis of natural coiled-coil sequences and structures. We find that when located centrally, rather than near the termini of such coiled-coil sequences, Asn does exert the anticipated oligomer-specifying influence. However, outside of these bounds, Asn is observed less frequently in the natural sequences, and the synthetic peptides are hyperthermostable and lose oligomer-state specificity. These findings highlight that not all regions of coiled-coil repeat sequences are equivalent, and that care is needed when designing coiled-coil interfaces.

  10. Analysis and simulation of a magnetic bearing suspension system for a laboratory model annular momentum control device

    NASA Technical Reports Server (NTRS)

    Groom, N. J.; Woolley, C. T.; Joshi, S. M.

    1981-01-01

    A linear analysis and the results of a nonlinear simulation of a magnetic bearing suspension system which uses permanent magnet flux biasing are presented. The magnetic bearing suspension is part of a 4068 N-m-s (3000 lb-ft-sec) laboratory model annular momentum control device (AMCD). The simulation includes rigid body rim dynamics, linear and nonlinear axial actuators, linear radial actuators, axial and radial rim warp, and power supply and power driver current limits.

  11. Multiphysics modelling of multibody systems: application to car semi-active suspensions

    NASA Astrophysics Data System (ADS)

    Docquier, N.; Poncelet, A.; Delannoy, M.; Fisette, P.

    2010-12-01

    The goal of the present article is to analyse the performances of a modern vehicle equipped with a novel suspension system linking front, rear, right and left cylinders via a semi-active hydraulic circuit, developed by the Tenneco Automotive company. In addition to improving the vehicle's vertical performances (in terms of comfort), both the stiff roll motion of the carbody and the soft wrap motion of the rear/front wheel-axle units can be obtained and tuned via eight electrovalves. The proposed system avoids the use of classical anti-roll bars, which would be incompatible with the wrap performance. A major problem of the project is to produce a realistic and efficient 3D multibody dynamic model of an Audi A6 coupled, at the equational level, with an hydraulic model of the suspension including cylinders, accumulators, valve characteristics, oil compressibility and pipe dynamics. As regards the hydraulic submodel, a particular attention is paid to assemble resistive components properly without resorting to the use of artificial volumes, as proposed by some software dealing with the dynamics of hydraulic systems. According to Tenneco Automotive requirements, this model must be produced in a Matlab/Simulink form, in particular for control purposes. Thanks to the symbolic approach underlying our multibody program; a unified hybrid model can be obtained as a unique plant dynamic block to be real-time integrated in the Simulink environment on a standard computer. Simulation results highlight the advantages of this new suspension system, in particular regarding the behaviour of the car which can remain stiff in roll for curve negotiation, while maintaining a soft wrap behaviour on uneven surfaces.

  12. Starch gelatinization in coiled heaters.

    PubMed

    Kelder, J D H; Ptasinski, K J; Kerkhof, P J A M

    2004-01-01

    A gelatinizing model food derived from a 5% w/w cross-linked waxy maize starch suspension was simulated in coiled heaters to assess the impact of centrifugal forces on flow and heat transfer. For four coil diameters (D = 0.25, 1, 2.5, and infinity m) and three flow rates (w = 0.5, 1, and 2 m/s), heat transfer, viscous development, and the severity of channeling were evaluated. Increasing curvature proved to suppress channeling as a result of more uniform heating and gelatinization. The maximum attainable viscosity was also higher, implying a lower starch consumption for a target viscosity. Higher flow rates necessitated longer heaters, and the maximum viscosity decreased. Moderate product velocities are therefore recommended.

  13. Design and simulation of printed spiral coil used in wireless power transmission systems for implant medical devices.

    PubMed

    Wu, Wei; Fang, Qiang

    2011-01-01

    Printed Spiral Coil (PSC) is a coil antenna for near-field wireless power transmission to the next generation implant medical devices. PSC for implant medical device should be power efficient and low electromagnetic radiation to human tissues. We utilized a physical model of printed spiral coil and applied our algorithm to design PSC operating at 13.56 MHz. Numerical and electromagnetic simulation of power transfer efficiency of PSC in air medium is 77.5% and 71.1%, respectively. The simulation results show that the printed spiral coil which is optimized for air will keep 15.2% power transfer efficiency in human subcutaneous tissues. In addition, the Specific Absorption Ratio (SAR) for this coil antenna in subcutaneous at 13.56 MHz is below 1.6 W/Kg, which suggests this coil is implantable safe based on IEEE C95.1 safety guideline.

  14. Annoyance rate evaluation method on ride comfort of vehicle suspension system

    NASA Astrophysics Data System (ADS)

    Tang, Chuanyin; Zhang, Yimin; Zhao, Guangyao; Ma, Yan

    2014-03-01

    The existing researches of the evaluation method of ride comfort of vehicle mainly focus on the level of human feelings to vibration. The level of human feelings to vibration is influenced by many factors, however, the ride comfort according to the common principle of probability and statistics and simple binary logic is unable to reflect these uncertainties. The random fuzzy evaluation model from people subjective response to vibration is adopted in the paper, these uncertainties are analyzed from the angle of psychological physics. Discussing the traditional evaluation of ride comfort during vehicle vibration, a fuzzily random evaluation model on the basis of annoyance rate is proposed for the human body's subjective response to vibration, with relevant fuzzy membership function and probability distribution given. A half-car four degrees of freedom suspension vibration model is described, subject to irregular excitations from the road surface, with the aid of software Matlab/Simulink. A new kind of evaluation method for ride comfort of vehicles is proposed in the paper, i.e., the annoyance rate evaluation method. The genetic algorithm and neural network control theory are used to control the system. Simulation results are obtained, such as the comparison of comfort reaction to vibration environments between before and after control, relationship of annoyance rate to vibration frequency and weighted acceleration, based on ISO 2631/1(1982), ISO 2631-1(1997) and annoyance rate evaluation method, respectively. Simulated assessment results indicate that the proposed active suspension systems prove to be effective in the vibration isolation of the suspension system, and the subjective response of human being can be promoted from very uncomfortable to a little uncomfortable. Furthermore, the novel evaluation method based on annoyance rate can further estimate quantitatively the number of passengers who feel discomfort due to vibration. A new analysis method of vehicle

  15. Double integrating sphere system for optical parameter determination of industrial suspensions

    NASA Astrophysics Data System (ADS)

    Keränen, Ville T. J.; Mäkynen, Anssi J.

    2008-06-01

    The main objective of this study was to construct a double integrating sphere system and to verify its performance using Intralipid fat emulsion. The final goal was to be able to determine optical properties of various turbid suspensions with the proposed system. Online measurements even would have been possible as backscattering and forward scattering were measured simultaneously. The measured suspension was injected in a cuvette placed between two integrating spheres and illuminated with a laser through the first sphere. The diameter of the spheres was 8" and the diameter of the sample port could have been varied up to 2.5". The cuvette was made of plastic and optical grade glass and its diameter was sufficient to cover the sample port area. The sample thickness in the measurement cuvette was 5 mm. Optical powers were detected using fiber coupled photodiodes. There was one diode for each sphere and one for the unscattered light at the opposite end of the sphere system facing towards the laser. The measured optical powers were converted to absorption coefficient, scattering coefficient and if possible to anisotropy using an inverse adding-doubling method. The results measured for the Intralipid using the described system corresponded with those documented in published literature. A number of pulp samples with unknown optical properties were measured with encouraging results. However, the differences between different pulps and fillers are so small that, in the future, the focus will be in error source elimination to achieve reasonable accuracy.

  16. Vehicle active suspension system using skyhook adaptive neuro active force control

    NASA Astrophysics Data System (ADS)

    Priyandoko, G.; Mailah, M.; Jamaluddin, H.

    2009-04-01

    This paper aims to highlight the practical viability of a new and novel hybrid control technique applied to a vehicle active suspension system of a quarter car model using skyhook and adaptive neuro active force control (SANAFC). The overall control system essentially comprises four feedback control loops, namely the innermost proportional-integral (PI) control loop for the force tracking of the pneumatic actuator, the intermediate skyhook and active force control (AFC) control loops for the compensation of the disturbances and the outermost proportional-integral-derivative (PID) control loop for the computation of the optimum target/commanded force. A neural network (NN) with a modified adaptive Levenberg-Marquardt learning algorithm was used to approximate the estimated mass and inverse dynamics of the pneumatic actuator in the AFC loop. A number of experiments were carried out on a physical test rig using a hardware-in-the-loop configuration that fully incorporates the theoretical elements. The performance of the proposed control method was evaluated and compared to examine the effectiveness of the system in suppressing the vibration effect on the suspension system. It was found that the simulation and experimental results were in good agreement, particularly for the sprung mass displacement and acceleration behaviours in which the proposed SANAFC scheme is found to outperform the PID and passive counterparts.

  17. ASPS performance with large payloads onboard the Shuttle Orbiter. [Annular Suspension and Pointing System

    NASA Technical Reports Server (NTRS)

    Keckler, C. R.

    1980-01-01

    A high fidelity digital computer simulation was used to establish the viability of the Annular Suspension and Pointing System (ASPS) for satisfying the pointing and stability requirements of facility class payloads, such as the Solar Optical Telescope, when subjected to the Orbiter disturbance environment. The ASPS and its payload were subjected to disturbances resulting from crew motions in the Orbiter aft flight deck and VRCS thruster firings. Worst case pointing errors of 0.005 arc seconds were experienced under the disturbance environment simulated; this is well within the 0.08 arc seconds requirement specified by the payload.

  18. Aneurysm of an Anomalous Systemic Artery Supplying the Normal Basal Segments of the Left Lower Lobe: Endovascular Treatment with the Amplatzer Vascular Plug II and Coils

    SciTech Connect

    Canyigit, Murat Gumus, Mehmet; Kilic, Evrim; Erol, Bekir; Cetin, Huseyin; Hasanoglu, Hatice Canan; Arslan, Halil

    2011-02-15

    An anomalous systemic artery originating from the descending thoracic aorta supplying the normal basal segments of the lower lobe of the left lung without sequestration is a rare congenital anomaly. The published surgical treatments include lobectomy, segmentectomy, anastomosis, and ligation. In addition, endovascular treatment with coils has been reported. A second-generation occluder, the Amplatzer Vascular Plug II (AVP II), has a central plug and two occlusion disks and a finer, more densely woven nitinol wire, thus enabling faster embolization. This published case is the first successful occlusion of an aneurysm of an anomalous systemic artery with the AVP II and fibered coils, with 10 months of follow-up.

  19. Method and apparatus for identifying conductive objects by monitoring the true resistive component of impedance change in a coil system caused by the object

    DOEpatents

    Gregory, William D.; Capots, Larry H.; George, James P.; Janik, Richard

    1981-01-01

    The type of conductor, its property, and if a metal, its type and cross-sectional area can be obtained from measurements made at different frequencies for the amount of unbalance created in a previously balanced stable coil detection system. The true resistive component is accurately measured and thus reflects only the voltage loss attributable to eddy currents caused by introduction of the test sample to the coil system. This voltage divided by corresponding applied frequency gives a curve which peaks at a frequency dependent upon type of conductor. For a metal this peak frequency is proportional to the samples resistivity divided by its cross-sectional area.

  20. Note: Magnetic targeting for enhancement of the activation efficiency of G protein-coupled receptor with a two-pair coil system.

    PubMed

    Cao, Quanliang; Han, Xiaotao; Chun, Lei; Liu, Jianfeng; Li, Liang

    2016-01-01

    Insufficient contact of drug with target cells is a primary reason for limited efficiency of G protein-coupled receptor activation. To overcome this limitation, a simple approach based on magnetic targeting for enhancing drug delivery towards the cell surfaces using magnetic nanoparticles and a two-pair coil system consisting of Helmholtz and Maxwell coils was reported. As a proof of the concept, comparative experiments on G protein-coupled receptor activation process were carried out and results show that the efficiency of G protein-coupled receptor activation can be increased about 6 times in the experiments with the aid of the proposed magnetic targeting system.

  1. High angle of attack position sensing for the Southampton University magnetic suspension and balance system

    NASA Technical Reports Server (NTRS)

    Parker, David H.

    1987-01-01

    An all digital five channel position detection system is to be installed in the Southampton University Magnetic Suspension and Balance System (SUMSBS). The system is intended to monitor a much larger range of model pitch attitudes than has been possible hitherto, up to a maximum of a 90 degree angle of attack. It is based on the use of self-scanning photodiode arrays and illuminating laser light beams, together with purpose built processing electronics. The principles behind the design of the system are discussed, together with the results of testing one channel of the system which was used to control the axial position of a magnetically suspended model in SUMSBS. The removal of optically coupled heave position information from the axial position sensing channel is described.

  2. Optimised configuration of sensors for fault tolerant control of an electro-magnetic suspension system

    NASA Astrophysics Data System (ADS)

    Michail, K.; Zolotas, A. C.; Goodall, R. M.; Whidborne, J. F.

    2012-10-01

    For any given system the number and location of sensors can affect the closed-loop performance as well as the reliability of the system. Hence, one problem in control system design is the selection of the sensors in some optimum sense that considers both the system performance and reliability. Although some methods have been proposed that deal with some of the aforementioned aspects, in this work, a design framework dealing with both control and reliability aspects is presented. The proposed framework is able to identify the best sensor set for which optimum performance is achieved even under single or multiple sensor failures with minimum sensor redundancy. The proposed systematic framework combines linear quadratic Gaussian control, fault tolerant control and multiobjective optimisation. The efficacy of the proposed framework is shown via appropriate simulations on an electro-magnetic suspension system.

  3. Interface stress in socket/residual limb with transtibial prosthetic suspension systems during locomotion on slopes and stairs.

    PubMed

    Eshraghi, Arezoo; Abu Osman, Noor Azuan; Gholizadeh, Hossien; Ali, Sadeeq; Abas, Wan Abu Bakar Wan

    2015-01-01

    This study aimed to compare the effects of different suspension methods on the interface stress inside the prosthetic sockets of transtibial amputees when negotiating ramps and stairs. Three transtibial prostheses, with a pin/lock system, a Seal-In system, and a magnetic suspension system, were created for the participants in a prospective study. Interface stress was measured as the peak pressure by using the F-socket transducers during stairs and ramp negotiation. Twelve individuals with transtibial amputation managed to complete the experiments. During the stair ascent and descent, the greatest peak pressure was observed in the prosthesis with the Seal-In system. The magnetic prosthetic suspension system caused significantly different peak pressure at the anterior proximal region compared with the pin/lock (P = 0.022) and Seal-In (P = 0.001) during the stair ascent. It was also observed during the stair descent and ramp negotiation. The prostheses exhibited varying pressure profiles during the stair and ramp ascent. The prostheses with the pin/lock and magnetic suspension systems exhibited lower peak pressures compared with the Seal-In system. The intrasystem pressure distribution at the anterior and posterior regions of the residual limb was fairly homogenous during the stair and ramp ascent and descent. Nevertheless, the intrasystem pressure mapping revealed a significant difference among the suspension types, particularly at the anterior and posterior sensor sites.

  4. Development of the design concepts for a medium-scale wind tunnel magnetic suspension system

    NASA Technical Reports Server (NTRS)

    Humphris, R. R.; Zapata, R. N.

    1982-01-01

    The magnitude of AC losses from a superconducting coil strongly indicates that the predicted scaling lawa are valid. The stainless steel bands around the test coil were the source of additional helium boiloff due to a transformer action and, hence, caused erroneously high AC loss measurements in the first run. However, removal of these bands for the second run produced data which are consistent with previous results on small scale multifilamentary superconducting coils.

  5. Evolutionary Patterns in Coiled-Coils

    PubMed Central

    Surkont, Jaroslaw; Pereira-Leal, Jose B.

    2015-01-01

    Models of protein evolution are used to describe evolutionary processes, for phylogenetic analyses and homology detection. Widely used general models of protein evolution are biased toward globular domains and lack resolution to describe evolutionary processes for other protein types. As three-dimensional structure is a major constraint to protein evolution, specific models have been proposed for other types of proteins. Here, we consider evolutionary patterns in coiled-coil forming proteins. Coiled-coils are widespread structural domains, formed by a repeated motif of seven amino acids (heptad repeat). Coiled-coil forming proteins are frequently rods and spacers, structuring both the intracellular and the extracellular spaces that often form protein interaction interfaces. We tested the hypothesis that due to their specific structure the associated evolutionary constraints differ from those of globular proteins. We showed that substitution patterns in coiled-coil regions are different than those observed in globular regions, beyond the simple heptad repeat. Based on these substitution patterns we developed a coiled-coil specific (CC) model that in the context of phylogenetic reconstruction outperforms general models in tree likelihood, often leading to different topologies. For multidomain proteins containing both a coiled-coil region and a globular domain, we showed that a combination of the CC model and a general one gives higher likelihoods than a single model. Finally, we showed that the model can be used for homology detection to increase search sensitivity for coiled-coil proteins. The CC model, software, and other supplementary materials are available at http://www.evocell.org/cgl/resources (last accessed January 29, 2015). PMID:25577198

  6. Laser-induced breakdown system for colloid characterization in dilute aqueous suspensions

    SciTech Connect

    Brachman, A; Mihardja, S; Palmer, C A; Wruck, D

    1999-08-11

    Detection and sizing of colloids by acoustic detection of laser-induced breakdown and elemental analysis of colloids by laser-induced breakdown spectroscopy are investigated in dilute aqueous suspensions. Development and testing of the methods are performed with standard polystyrene suspensions and prepared suspensions of defined composition and particle size. Application of the methods to analysis of field and laboratory samples is discussed. Am atomic emission lines are observed by laser-induced breakdown spectroscopy of an Am hydroxycarbonate suspension.

  7. Magnetic propulsion of a magnetic device using three square-Helmholtz coils and a square-Maxwell coil.

    PubMed

    Ha, Yong H; Han, Byung H; Lee, Soo Y

    2010-02-01

    We introduce a square coil system for remote magnetic navigation of a magnetic device without any physical movements of the coils. We used three square-Helmholtz coils and a square-Maxwell coil for magnetic propulsion of a small magnet along the desired path. All the square coils are mountable on a cubic frame that has an opening to accommodate a living subject. The square-Helmholtz coils control the magnetic propulsion direction by generating uniform magnetic field along the desired direction while the square-Maxwell coil controls the propulsion force by generating magnetic gradient field. We performed magnetic propulsion experiments with a down-scaled coil set and a three-channel coil driver. Experimental results demonstrate that we can use the square coil set for magnetic navigation of a magnetic device without any physical movements of the coils.

  8. Partition Efficiency of High-Pitch Locular Multilayer Coil for Countercurrent Chromatographic Separation of Proteins Using Small-Scale Cross-Axis Coil Planet Centrifuge and Application to Purification of Various Collagenases with Aqueous-Aqueous Polymer Phase Systems

    PubMed Central

    Shinomiya, Kazufusa; Kobayashi, Hiroko; Inokuchi, Norio; Nakagomi, Kazuya; Ito, Yoichiro

    2010-01-01

    Partition efficiency of the high-pitch locular multilayer coil was evaluated in countercurrent chromatographic (CCC) separation of proteins with an aqueous-aqueous polymer phase system using the small-scale cross-axis coil planet centrifuge (X-axis CPC) fabricated in our laboratory. The separation column was specially made by high-pitch (ca 5 cm) winding of 1.0 mm I.D., 2.0 mm O.D. locular tubing compressed at 2 cm intervals with a total capacity of 29.5 mL. The protein separation was performed using a set of stable proteins including cytochrome C, myoglobin, and lysozyme with the 12.5% (w/w) polyethylene glycol (PEG) 1000 and 12.5% (w/w) dibasic potassium phosphate system (pH 9.2) under 1000 rpm of column revolution. This high-pitch locular tubing yielded substantially increased stationary phase retention than the normal locular tubing for both lower and upper mobile phases. In order to demonstrate the capability of the high-pitch locular tubing, the purification of collagenase from the crude commercial sample was carried out using an aqueous-aqueous polymer phase system. Using the 16.0% (w/w) PEG 1000 – 6.3% (w/w) dibasic potassium phosphate – 6.3% (w/w) monobasic potassium phosphate system (pH 6.6), collagenase I, II, V and X derived from Clostridium hystolyticum were separated from other proteins and colored small molecular weight compounds present in the crude commercial sample, while collagenase N-2 and S-1 from Streptomyces parvulus subsp. citrinus were eluted with impurities at the solvent front with the upper phase. The collagenase from C. hystolyticum retained its enzymatic activity in the purified fractions. The overall results demonstrated that the high-pitch locular multilayer coil is effectively used for the CCC purification of bioactive compounds without loss of their enzymatic activities. PMID:21869859

  9. Partition Efficiency of High-Pitch Locular Multilayer Coil for Countercurrent Chromatographic Separation of Proteins Using Small-Scale Cross-Axis Coil Planet Centrifuge and Application to Purification of Various Collagenases with Aqueous-Aqueous Polymer Phase Systems.

    PubMed

    Shinomiya, Kazufusa; Kobayashi, Hiroko; Inokuchi, Norio; Nakagomi, Kazuya; Ito, Yoichiro

    2011-01-01

    Partition efficiency of the high-pitch locular multilayer coil was evaluated in countercurrent chromatographic (CCC) separation of proteins with an aqueous-aqueous polymer phase system using the small-scale cross-axis coil planet centrifuge (X-axis CPC) fabricated in our laboratory. The separation column was specially made by high-pitch (ca 5 cm) winding of 1.0 mm I.D., 2.0 mm O.D. locular tubing compressed at 2 cm intervals with a total capacity of 29.5 mL. The protein separation was performed using a set of stable proteins including cytochrome C, myoglobin, and lysozyme with the 12.5% (w/w) polyethylene glycol (PEG) 1000 and 12.5% (w/w) dibasic potassium phosphate system (pH 9.2) under 1000 rpm of column revolution. This high-pitch locular tubing yielded substantially increased stationary phase retention than the normal locular tubing for both lower and upper mobile phases. In order to demonstrate the capability of the high-pitch locular tubing, the purification of collagenase from the crude commercial sample was carried out using an aqueous-aqueous polymer phase system. Using the 16.0% (w/w) PEG 1000 - 6.3% (w/w) dibasic potassium phosphate - 6.3% (w/w) monobasic potassium phosphate system (pH 6.6), collagenase I, II, V and X derived from Clostridium hystolyticum were separated from other proteins and colored small molecular weight compounds present in the crude commercial sample, while collagenase N-2 and S-1 from Streptomyces parvulus subsp. citrinus were eluted with impurities at the solvent front with the upper phase. The collagenase from C. hystolyticum retained its enzymatic activity in the purified fractions. The overall results demonstrated that the high-pitch locular multilayer coil is effectively used for the CCC purification of bioactive compounds without loss of their enzymatic activities.

  10. Coil Welding Aid

    NASA Technical Reports Server (NTRS)

    Wiesenbach, W. T.; Clark, M. C.

    1983-01-01

    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  11. Coil Welding Aid

    NASA Technical Reports Server (NTRS)

    Wiesenbach, W. T.; Clark, M. C.

    1983-01-01

    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  12. Antithrombogenicity of the Gyro permanently implantable pump with the RPM dynamic suspension system for the impeller.

    PubMed

    Ichikawa, Seiji; Nonaka, Kenji; Motomura, Tadashi; Ishitoya, Hiroshi; Watanabe, Kuniyoshi; Ashizawa, Satoshi; Shinohara, Toshiyuki; Sumikura, Hirohito; Ichihashi, Fumiyuki; Oestmann, Daniel; Nosé, Yukihiko

    2003-10-01

    In 1995, a group at Baylor College of Medicine started to develop the NEDO biventricular assist device (BVAD) using two Gyro permanently implantable (PI) centrifugal pumps. This pump consists of a sealless pump housing and an impeller supported with a double pivot bearing. In May 2001, an RPM dynamic suspension system (RPM-DS) for the impeller was developed to improve durability and antithrombogenicity without a complex magnetic suspension system. From March 2000 to March 2002, eight BVAD bovine experimental studies were performed for more than 1 month. Two pumps were implanted in two cases without the RPM-DS (group A) and in six cases with the RPM-DS (group B). In group A, the survival period was 45 and 50 days. The primary reason for termination was an increase in the requiring power, which was related to deposition of white thrombus on the bottom bearing. In group B, the survival period was 37, 48, 51, 60, 80, and 90 days. The reasons for termination were not related to thrombus formation. No thrombus was observed in the pumps except for one right pump. In that experiment, the thrombus formation may have occurred when that pump had a low flow rate at a level of 1 L/min for 6 hr. These studies demonstrate the apparent antithrombogenic effect of RPM-DS. The NEDO BVAD is ready to move into a 3-month preclinical system evaluation.

  13. Robust control of nonlinear MAGLEV suspension system with mismatched uncertainties via DOBC approach.

    PubMed

    Yang, Jun; Zolotas, Argyrios; Chen, Wen-Hua; Michail, Konstantinos; Li, Shihua

    2011-07-01

    Robust control of a class of uncertain systems that have disturbances and uncertainties not satisfying "matching" condition is investigated in this paper via a disturbance observer based control (DOBC) approach. In the context of this paper, "matched" disturbances/uncertainties stand for the disturbances/uncertainties entering the system through the same channels as control inputs. By properly designing a disturbance compensation gain, a novel composite controller is proposed to counteract the "mismatched" lumped disturbances from the output channels. The proposed method significantly extends the applicability of the DOBC methods. Rigorous stability analysis of the closed-loop system with the proposed method is established under mild assumptions. The proposed method is applied to a nonlinear MAGnetic LEViation (MAGLEV) suspension system. Simulation shows that compared to the widely used integral control method, the proposed method provides significantly improved disturbance rejection and robustness against load variation.

  14. Description of the Large Gap Magnetic Suspension System (LGMSS) ground-based experiment

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.

    1991-01-01

    A description of the Large Gap Magnetic Suspension System (LGMSS) ground-based experiment is presented. The LGMSS provides five degrees of freedom control of a cylindrical suspended element which is levitated above a floor-mounted array of air core electromagnets. The uncontrolled degree of freedom is rotation about the long axis of the cylinder (roll). Levitation and control forces are produced on a permanent magnet core which is embedded in the cylinder. The cylinder also contains light emitting diodes (LEDs), assorted electrons, and a power supply. The LEDs provide active targets for an optical position measurement system which is being developed in-house at the Langley Research Center. The optical position measurement system will provide six degrees of freedom position information for the LGMSS control system.

  15. Test equipment for a flywheel energy storage system using a magnetic bearing composed of superconducting coils and superconducting bulks

    NASA Astrophysics Data System (ADS)

    Ogata, M.; Matsue, H.; Yamashita, T.; Hasegawa, H.; Nagashima, K.; Maeda, T.; Matsuoka, T.; Mukoyama, S.; Shimizu, H.; Horiuchi, S.

    2016-05-01

    Energy storage systems are necessary for renewable energy sources such as solar power in order to stabilize their output power, which fluctuates widely depending on the weather. Since ‘flywheel energy storage systems’ (FWSSs) do not use chemical reactions, they do not deteriorate due to charge or discharge. This is an advantage of FWSSs in applications for renewable energy plants. A conventional FWSS has capacity limitation because of the mechanical bearings used to support the flywheel. Therefore, we have designed a superconducting magnetic bearing composed of a superconducting coil stator and a superconducting bulk rotor in order to solve this problem, and have experimentally manufactured a large scale FWSS with a capacity of 100 kWh and an output power of 300 kW. The superconducting magnetic bearing can levitate 4 tons and enables the flywheel to rotate smoothly. A performance confirmation test will be started soon. An overview of the superconducting FWSS is presented in this paper.

  16. Rectangular coils optimization for wireless power transmission

    NASA Astrophysics Data System (ADS)

    Duan, Zhu; Guo, Yong-Xin; Kwong, Dim-Lee

    2012-01-01

    Wirelessly coupled coils are crucial for efficient power transmission in various applications. Previous design methods are only eligible for improving the efficiency of circular or square coils. This paper presents a method of characterizing and optimizing rectangular coils used in inductively coupled systems. After setting up a lumped component model for inductive coils, the efficiency can be expressed in terms of geometrical parameters of the coils. Subsequently, the power efficiency can be plotted versus these parameters in Matlab, thus getting the desired coils for optimum power transfer. With this design procedure from mathematical optimization, we eventually designed two rectangular coils spaced 10 mm apart, which achieves a power transmission efficiency of 46.4% at a frequency of 3 MHz. The design methodology is verified by simulation and measurement.

  17. An experimental study of the flow of LPG as refrigerant inside an adiabatic helical coiled capillary tube in vapour compression refrigeration system

    NASA Astrophysics Data System (ADS)

    Punia, Sanjeev Singh; Singh, Jagdev

    2015-11-01

    This paper presents an experimental investigation for the flow of liquefied petroleum gas (LPG) as a refrigerant inside an adiabatic helically coiled capillary tube in vapour compression refrigeration system. The effect of various geometric parameters and operating conditions like capillary tube inner diameter, length of capillary tube, coil diameter and different inlet subcoolings on the mass flow rate of LPG through the helical coiled capillary tube geometry has been investigated. It has been established that the coil diameter significantly influences the mass flow rate of LPG through the adiabatic helical capillary tube. It has been concluded that the effect of coiling of capillary tube reduces the mass flow rate by 5-12 % as compared to those of the straight capillary tube operating under similar conditions. The data obtained from the experiments are analyzed and a dimensionless correlation has been developed. The proposed correlation predicts that more than 90 % of experimental data which is in agreement with measured data in an error band of ±10 %.

  18. System concept definition of the Grumman superconducting Electromagnetic Suspension (EMS) Maglev design

    NASA Astrophysics Data System (ADS)

    Proise, M.

    1994-05-01

    Grumman, under contract to the Army Corps of Engineers, completed a System Concept Definition (SCD) study to design a high-speed 134 m/s (300 m.p.h.) magnetically levitated (Maglev) transportation system. The primary development goals were to design a Maglev that is safe, reliable, environmentally acceptable, and low-cost. The cost issue was a predominant one, since previous studies have shown that an economically viable Maglev system (one that is attractive to investors for future models of passenger and/or freight transportation) requires a cost that is about $12.4 M/km ($20 Million per mile). The design is based on the electromagnetic suspension (EMS) system using superconducting iron-core magnets mounted along both sides of the vehicle. The EMS system has several advantages compared to the electrodynamic suspension (EDS) Maglev systems such as low stray magnetic fields in the passenger cabin and the surrounding areas, uniform load distribution along the full length of the vehicle, and small pole pitch for smoother propulsion and ride comfort. It is also levitated at all speeds and incorporates a wrap-around design of safer operation. The Grumman design has all the advantages of an EMS system identified above, while eliminating (or significantly improving) drawbacks associated with normal magnet powered EMS systems. Improvements include larger gap clearance, lighter weight, lower number of control servos, and higher off line switching speeds. The design also incorporates vehicle tilt (plus or minus 9 deg) for higher coordinated turn and turn out speed capability.

  19. System concept definition of the Grumman superconducting Electromagnetic Suspension (EMS) Maglev design

    NASA Technical Reports Server (NTRS)

    Proise, M.

    1994-01-01

    Grumman, under contract to the Army Corps of Engineers, completed a System Concept Definition (SCD) study to design a high-speed 134 m/s (300 m.p.h.) magnetically levitated (Maglev) transportation system. The primary development goals were to design a Maglev that is safe, reliable, environmentally acceptable, and low-cost. The cost issue was a predominant one, since previous studies have shown that an economically viable Maglev system (one that is attractive to investors for future models of passenger and/or freight transportation) requires a cost that is about $12.4 M/km ($20 Million per mile). The design is based on the electromagnetic suspension (EMS) system using superconducting iron-core magnets mounted along both sides of the vehicle. The EMS system has several advantages compared to the electrodynamic suspension (EDS) Maglev systems such as low stray magnetic fields in the passenger cabin and the surrounding areas, uniform load distribution along the full length of the vehicle, and small pole pitch for smoother propulsion and ride comfort. It is also levitated at all speeds and incorporates a wrap-around design of safer operation. The Grumman design has all the advantages of an EMS system identified above, while eliminating (or significantly improving) drawbacks associated with normal magnet powered EMS systems. Improvements include larger gap clearance, lighter weight, lower number of control servos, and higher off line switching speeds. The design also incorporates vehicle tilt (plus or minus 9 deg) for higher coordinated turn and turn out speed capability.

  20. High-resolution small field-of-view magnetic resonance image acquisition system using a small planar coil and a pneumatic manipulator in an open MRI scanner.

    PubMed

    Miki, Kohei; Masamune, Ken

    2015-10-01

    Low-field open magnetic resonance imaging (MRI) is frequently used for performing image-guided neurosurgical procedures. Intraoperative magnetic resonance (MR) images are useful for tracking brain shifts and verifying residual tumors. However, it is difficult to precisely determine the boundary of the brain tumors and normal brain tissues because the MR image resolution is low, especially when using a low-field open MRI scanner. To overcome this problem, a high-resolution MR image acquisition system was developed and tested. An MR-compatible manipulator with pneumatic actuators containing an MR signal receiver with a small radiofrequency (RF) coil was developed. The manipulator had five degrees of freedom for position and orientation control of the RF coil. An 8-mm planar RF coil with resistance and inductance of 2.04 [Formula: see text] and 1.00 [Formula: see text] was attached to the MR signal receiver at the distal end of the probe. MR images of phantom test devices were acquired using the MR signal receiver and normal head coil for signal-to-noise ratio (SNR) testing. The SNR of MR images acquired using the MR signal receiver was 8.0 times greater than that of MR images acquired using the normal head coil. The RF coil was moved by the manipulator, and local MR images of a phantom with a 2-mm grid were acquired using the MR signal receiver. A wide field-of-view MR image was generated from a montage of local MR images. A small field-of-view RF system with a pneumatic manipulator was integrated in a low-field MRI scanner to allow acquisition of both wide field-of-view and high-resolution MR images. This system is promising for image-guided neurosurgery as it may allow brain tumors to be observed more clearly and removed precisely.

  1. Long Arc Simulated Lightning Attachment Testing Using a 150 kW Tesla Coil

    DTIC Science & Technology

    1979-06-01

    Coil System L4=Secondary of Tesla Coil System LS=Extra Coil of Tesla Coil System Cl=Primary Circuit Charging Capactor C2=Distributed...The fields outside the coil near the center (half way up) loop outward, with the frequency of the output and the magnetic flux changing, the arc is

  2. Cartilage suspension using a poly (lactic-co-glycolic) acid system.

    PubMed

    Jeong, Jae Hoon; Kim, Byung Hwi; Kim, Dae Hee; Kim, Baek-Kyu; Pak, Chang Sik; Kim, Eun Hee; Heo, Chan Yeong

    2017-07-01

    This study aims to determine whether a bar-like implant made of poly lactic-co-glycolic acid (PLGA) could be used for cartilage suspension and whether the implant would be suitable for rhinoplasty. Three types of in vivo animal experiments were performed. First, the ear cartilage was incised in a full-thickness pattern, and the PLGA system was placed between the upper and lower cartilage to offer support to the tissue. Second, after the ear cartilage was forcibly bent, an implant was placed in the cartilage. For these rabbits, the outer aspect of the ear cartilage was assessed at 2, 4, 8, 10, and 12 weeks postoperatively. In addition, tissue samples were collected for histological evaluation 12 weeks after surgery. Third, the bar-like nasal implant was used for nasal septal suspension. We obtained micro-computed tomography (CT) images and evaluated the inflammatory reaction at 12 weeks postoperatively. The results of both the ear suspension and bending retention tests revealed that the characteristic shapes of the cartilage were well preserved at 12 weeks postoperatively. Moreover, no abnormal inflammatory reaction was present in any site in the experimental group. We successfully implanted the bar-like nasal implant in the rabbit's septum, and no complications occurred. Furthermore, the physical examination and the micro-CT images did not reveal any nasal obstruction or inflammation. We confirmed that an implant made of PLGA can be maintained in the cartilage tissue and believe that this can be applied in rhinoplasty as an alternative to autologous cartilage. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  3. In vivo evaluation of the NEDO biventricular assist device with an RPM dynamic impeller suspension system.

    PubMed

    Ichikawa, Seiji; Linneweber, Joerg; Motomura, Tadashi; Ishitoya, Hiroshi; Watanabe, Kuniyoshi; Ashizawa, Satoshi; Murai, Noriyuki; Nishimura, Ikuya; Sumikura, Hirohito; Glueck, Julia A; Shinohara, Toshiyuki; Oestmann, Daniel J; Nosé, Yukihiko

    2003-01-01

    Since 1995, the Baylor College of Medicine group has been developing the NEDO Gyro permanent implantable (PI) pump. The Gyro PI pump has achieved outstanding results up to 284 days with no thrombus formation during the left ventricular assist device (LVAD) animal experiments. However, in biventricular assist device (BVAD) animal experiments, thrombus formation did occur. An in vitro experiment showed the reason for thrombus formation was caused by the missed magnetic balance between the impeller and the actuator. On the basis of this result, the revolutions per minute (RPM) impeller suspension system was developed. Six long-term animal studies were performed in bovine models. Survival periods were 90, 80, 60, 51, 48, and 37 days, respectively. No thrombus was observed in the pumps with the exception of one right pump. In that experiment, the thrombus formation may have occurred when the pump had a low flow because of outflow kinking. In this article, the antithrombogenic effect of this RPM impeller suspension system will be discussed.

  4. Large-scale mammalian cell culture: Design and use of an economical batch suspension system.

    PubMed

    Tolbert, W R; Schoenfeld, R A; Lewis, C; Feder, J

    1982-07-01

    Large-scale mammalian cell culture in the absence of antibiotics requires stringent conditions of sterility for all vessels, procedure, and systems used. Application of existing fermentation technology suffers from the differences between mammalian and bacterial cultures. Relatively simple and inexpensive 100-L vessels have been designed specifically for medium storage and antibiotic-free mammalian cell culture. These vessels are portable and sterilized in a 2 x 3 x 5 ft conventional or VACUMATIC autoclave. They consist of 30-gal 316 stainless-steel sanitary process drums whose heads have been modified to meet the rapid pressure changes that occur during autoclaving. The vessels incorporate systems for aseptic introduction and removal of both liquids and gases required for inoculation, growth, and harvesting of cell suspensions. A two-disk vibromixer is used for agitation with inoculation at a laminar flow hood and incubation in a warm room. These vessels have been used for culture of one rat and eight human tumor lines for over 2 x 10(5) L of suspension.

  5. System for the exposure of cell suspensions to power-frequency electric fields.

    PubMed

    Kaune, W T; Frazier, M E; King, A J; Samuel, J E; Hungate, F P; Causey, S C

    1984-01-01

    A system is described that uses an oscillating magnetic field to produce power-frequency electric fields with strengths in excess of those produced in an animal or human standing under a high-voltage electric-power transmission line. In contrast to other types of exposure systems capable of generating fields of this size, no electrodes are placed in the conducting growth media: the possibility of electrode contamination of the exposed suspension is thereby eliminated. Electric fields in the range 0.02-3.5 V/m can be produced in a cell culture with total harmonic distortions less than 1.5%. The magnetic field used to produce electric fields for exposure is largely confined within a closed ferromagnetic circuit, and experimental and control cells are exposed to leakage magnetic flux densities less than 5 microT . The temperatures of the experimental and control cell suspensions are held fixed within +/- 0.1 degrees C by a water bath. Special chambers were developed to hold cell cultures during exposure and sham exposure. Chinese hamster ovary (CHO) cells incubated in these chambers grew for at least 48 h and had population doubling times of 16-17 h, approximately the same as for CHO cells grown under standard cell-culture conditions.

  6. A comparative study of flat coil and coil sensor for landslide detection

    NASA Astrophysics Data System (ADS)

    Sanjaya, Edi; Muslimin, Ahmad Novi; Djamal, Mitra; Suprijadi, Handayani, Gunawan; Ramli

    2016-03-01

    The landslide is one of the most costly catastrophic events in terms of human lives and infrastructure damage, thus an early warning monitoring for landslides becomes more and more important. Currently existing monitoring systems for early warning are available in terms of monolithic systems. This is a very cost-intensive way, considering installation as well as operational and personal expenses. We have been developing a landslide detection system based on flat coil and coil sensor. The flat coil element being developed is an inductive proximity sensor for detection mass of soil movement. The simple method of flat coil manufactures and low cost, is an attraction that is still inspired to develop flat coil sensors. Meanwhile, although it has a drawback in terms of their size, the coil sensor is still required in many fields due to their sensitivity and robustness. The simple method of coil manufacture and the materials are commonly available and low cost, is an attraction that is still inspired to develop induction coil sensors. A comparative study of alternative configuration of sensor based on flat coil elements and a coil in application to landslide detection has been discussed in this paper. The purpose of this comparison is to show the ideal conditions and the challenges for each sensor. Furthermore, a comparison between flat coil and coil sensor is presented.

  7. Optical measurement system applied to continuous displacement monitoring of long-span suspension bridges

    NASA Astrophysics Data System (ADS)

    Lages Martins, L.; Rebordão, J. M.; Ribeiro, A. S.

    2013-04-01

    This paper provides a general description of main issues related to the design of an optical measurement system applied to continuous displacement monitoring of long-span suspension bridges. The proposed system's architecture is presented and its main components - camera and active targets - are described in terms of geometrical and radiometric characteristics required for long distance measurement of the tridimensional displacement of the stiffness girder in the middle section of the bridge's central span. The intrinsic and extrinsic camera parameterization processes, which support the adopted measurement approach, are explained in a specific section. Since the designed measurement system is intended to perform continuous displacement monitoring in long distance observation framework, particular attention is given to environmental effects, namely, refraction, turbulence and sensor saturation phenomena, which can influence the displacement measurement accuracy. Finally, a measurement uncertainty method is discussed in order to provide a suitable solution for the determination of the accuracy related to the proposed measurement approach.

  8. Wind Tunnel Magnetic Suspension and Balance Systems With Transversely Magnetized Model Cores

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.

    1998-01-01

    This paper discusses the possibility of using vertically magnetized model cores for wind tunnel Magnetic Suspension and Balance Systems (MSBS) in an effort to resolve the traditional "roll control" problem. A theoretical framework is laid out, based on previous work related to generic technology development efforts at NASA Langley Research Center. The impact of the new roll control scheme on traditional wind tunnel MSBS configurations is addressed, and the possibility of demonstrating the new scheme with an existing electromagnet assembly is explored. The specific system considered is the ex- Massachusetts Institute of Technology (MIT), ex-NASA, 6-inch MSBS currently in the process of recommissioning at Old Dominion University. This system has a sufficiently versatile electromagnet configuration such that straightforward "conversion" to vertically magnetized cores appears possible.

  9. Wind Tunnel Magnetic Suspension and Balance Systems With Transversely Magnetized Model Cores

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.

    1998-01-01

    This paper discusses the possibility of using vertically magnetized model cores for wind tunnel Magnetic Suspension and Balance Systems (MSBS) in an effort to resolve the traditional "roll control" problem. A theoretical framework is laid out, based on previous work related to generic technology development efforts at NASA Langley Research Center. The impact of the new roll control scheme on traditional wind tunnel MSBS configurations is addressed, and the possibility of demonstrating the new scheme with an existing electromagnet assembly is explored. The specific system considered is the ex- Massachusetts Institute of Technology (MIT), ex-NASA, 6-inch MSBS currently in the process of recommissioning at Old Dominion University. This system has a sufficiently versatile electromagnet configuration such that straightforward "conversion" to vertically magnetized cores appears possible.

  10. Susceptibility Imaging in Glial Tumor Grading; Using 3 Tesla Magnetic Resonance (MR) System and 32 Channel Head Coil.

    PubMed

    Aydin, Omer; Buyukkaya, Ramazan; Hakyemez, Bahattin

    2017-01-01

    Susceptibility weighted imaging (SWI) is a velocity compensated, high-resolution three-dimensional (3D) spoiled gradient-echo sequence that uses magnitude and filtered-phase data. SWI seems to be a valuable tool for non-invasive evaluation of central nervous system gliomas. Relative cerebral blood volume (rCBV) ratio is one of the best noninvasive methods for glioma grading. Degree of intratumoral susceptibility signal (ITSS) on SWI correlates with rCBV ratio and histopathological grade. This study investigated the effectiveness of ITSS grading and rCBV ratio in preoperative assessment. Thirty-one patients (17 males and 14 females) with histopathogical diagnosis of glial tumor undergoing routine cranial MRI, SWI, and perfusion MRI examinations between October 2011 and July 2013 were retrospectively enrolled. All examinations were performed using 3T apparatus with 32-channel head coil. We used ITSS number for SWI grading. Correlations between SWI grade, rCBV ratio, and pathological grading were evaluated. ROC analysis was performed to determine the optimal rCBV ratio to distinguish between high-grade and low-grade glial tumors. There was a strong positive correlation between both pathological and SWI grading. We determined the optimal rCBV ratio to discriminate between high-grade and low-grade tumors to be 2.21. In conclusion, perfusion MRI and SWI using 3T MR and 32-channel head coil may provide useful information for preoperative glial tumor grading. SWI can be used as an accessory to perfusion MR technique in preoperative tumor grading.

  11. Susceptibility Imaging in Glial Tumor Grading; Using 3 Tesla Magnetic Resonance (MR) System and 32 Channel Head Coil

    PubMed Central

    Aydin, Omer; Buyukkaya, Ramazan; Hakyemez, Bahattin

    2017-01-01

    Summary Background Susceptibility weighted imaging (SWI) is a velocity compensated, high-resolution three-dimensional (3D) spoiled gradient-echo sequence that uses magnitude and filtered-phase data. SWI seems to be a valuable tool for non-invasive evaluation of central nervous system gliomas. Relative cerebral blood volume (rCBV) ratio is one of the best noninvasive methods for glioma grading. Degree of intratumoral susceptibility signal (ITSS) on SWI correlates with rCBV ratio and histopathological grade. This study investigated the effectiveness of ITSS grading and rCBV ratio in preoperative assessment. Material/Methods Thirty-one patients (17 males and 14 females) with histopathogical diagnosis of glial tumor undergoing routine cranial MRI, SWI, and perfusion MRI examinations between October 2011 and July 2013 were retrospectively enrolled. All examinations were performed using 3T apparatus with 32-channel head coil. We used ITSS number for SWI grading. Correlations between SWI grade, rCBV ratio, and pathological grading were evaluated. ROC analysis was performed to determine the optimal rCBV ratio to distinguish between high-grade and low-grade glial tumors. Results There was a strong positive correlation between both pathological and SWI grading. We determined the optimal rCBV ratio to discriminate between high-grade and low-grade tumors to be 2.21 Conslusions In conclusion, perfusion MRI and SWI using 3T MR and 32-channel head coil may provide useful information for preoperative glial tumor grading. SWI can be used as an accessory to perfusion MR technique in preoperative tumor grading. PMID:28439322

  12. Cryostat Suspension System Analysis During Cool-Down and its Validation

    NASA Astrophysics Data System (ADS)

    Saha, Subrata; Gupta, Anjan Dutta; Ahammed, Manir

    2017-04-01

    A superconducting-magnet-cryostat has a stainless steel cylindrical bobbin on which the Nb-Ti superconducting coils are wound. The bobbin along with the coil is cooled with liquid helium down to 4.2 K temperature. The bobbin is suspended inside a vacuum chamber with the help of three horizontal and six vertical glass-epoxy support-links. A detail analysis is made to predict the movement of the coil and the support link forces. After cool-down of the coil results of analysis is verified with the experimental data and found good agreement with the analysis. This paper presents the details of analysis as well as how the results are used to formulate the methodology for safe operation of support links and proper alignment of the coil.

  13. 48 CFR 209.407 - Suspension.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Suspension. 209.407... OF DEFENSE ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Debarment, Suspension, and Ineligibility 209.407 Suspension....

  14. Progress of magnetic suspension and balance systems for wind tunnels in the USSR

    NASA Technical Reports Server (NTRS)

    Kuzin, A. V.; Vyshkov, Y. D.; Shapovalov, G. K.

    1992-01-01

    Magnetic Suspension and Balance Systems (MSBS) for wind tunnels are being developed in order to solve the principal problems of aerodynamics which cannot be solved by conventional means: (1) measurements of aerodynamic loads acting on the aircraft models without the effects of mechanical supporting devices; and (2) the study of base pressure. This paper traces the progress of MSBS for wind tunnels in the Commonwealth of Independent States (CIS). The paper describes electromagnetic configuration, position sensing, and control and calibration systems of two wind tunnel MSBS existing in the CIS. The features of high-angle-of-attack control and roll control are discussed. The results of preliminary experiments on high-angle-of-attack and roll controls, digital control, and aerodynamic testing are also presented.

  15. Robust fixed-order dynamic output feedback controller design for nonlinear uncertain suspension system

    NASA Astrophysics Data System (ADS)

    Badri, Pouya; Amini, Amir; Sojoodi, Mahdi

    2016-12-01

    This paper deals with designing a robust fixed-order non-fragile dynamic output feedback controller for active suspension system of a quarter-car, by means of convex optimization and linear matrix inequalities (LMIs). Our purpose is to design a low-order controller that keeps the desired design specifications besides the simplicity of the implementation. The proposed controller is capable of asymptotically stabilizing the closed-loop system and developing H∞ control, despite model uncertainties and nonlinear dynamics of the quarter-car as well as the norm bounded perturbations of controller parameters. Furthermore, controller parameters are prevented from taking very large and undesirable amounts through appropriate LMI constraints. Finally, a numerical example is presented to show the effectiveness of the proposed method by comparing it with similar works.

  16. Some aspects of wind tunnel magnetic suspension systems with special application at large physical scales

    NASA Technical Reports Server (NTRS)

    Britcher, C. P.

    1983-01-01

    Wind tunnel magnetic suspension and balance systems (MSBSs) have so far failed to find application at the large physical scales necessary for the majority of aerodynamic testing. Three areas of technology relevant to such application are investigated. Two variants of the Spanwise Magnet roll torque generation scheme are studied. Spanwise Permanent Magnets are shown to be practical and are experimentally demonstrated. Extensive computations of the performance of the Spanwise Iron Magnet scheme indicate powerful capability, limited principally be electromagnet technology. Aerodynamic testing at extreme attitudes is shown to be practical in relatively conventional MSBSs. Preliminary operation of the MSBS over a wide range of angles of attack is demonstrated. The impact of a requirement for highly reliable operation on the overall architecture of Large MSBSs is studied and it is concluded that system cost and complexity need not be seriously increased.

  17. The modeling and design of the Annular Suspension and Pointing System /ASPS/. [for Space Shuttle

    NASA Technical Reports Server (NTRS)

    Kuo, B. C.; Lin, W. C. W.

    1979-01-01

    The Annular Suspension and Pointing System (ASPS) is a payload auxiliary pointing device of the Space Shuttle. The ASPS is comprised of two major subassemblies, a vernier and a coarse pointing subsystem. The three functions provided by the ASPS are related to the pointing of the payload, centering the payload in the magnetic actuator assembly, and tracking the payload mounting plate and shuttle motions by the coarse gimbals. The equations of motion of a simplified planar model of the ASPS are derived. Attention is given to a state diagram of the dynamics of the ASPS with position-plus-rate controller, the nonlinear spring characteristic for the wire-cable torque of the ASPS, the design of the analog ASPS through decoupling and pole placement, and the time response of different components of the continuous control system.

  18. Design Optimization for Suspension System of High Speed Train Using Neural Network

    NASA Astrophysics Data System (ADS)

    Kim, Young-Guk; Park, Chan-Kyoung; Hwang, Hee-Soo; Park, Tae-Won

    Design optimization has been performed for the suspension system of high speed train. Neural network and design of experiment (DOE) have been employed to build a meta-model for the system with 29 design variables and 46 responses. A combination of fractional factorial design and D-optimality design was used as an approach to DOE in order to reduce the number of experiments to a more practical level. As a result, only 66 experiments were enough. The 46 responses were divided into four performance index groups such as ride comfort, derailment quotient, unloading ratio and stability index. Four meta-models for each index group were constructed by use of neural network. For the learned meta-models, multi-criteria optimization was achieved by differential evolution. The results show that the proposed methodology yields a highly improved design in the ride comfort, unloading ratio and stability index.

  19. Collapsing granular suspensions.

    PubMed

    Kadau, D; Andrade, J S; Herrmann, H J

    2009-11-01

    A 2D contact dynamics model is proposed as a microscopic description of a collapsing suspension/soil to capture the essential physical processes underlying the dynamics of generation and collapse of the system. Our physical model is compared with real data obtained from in situ measurements performed with a natural collapsing/suspension soil. We show that the shear strength behavior of our collapsing suspension/soil model is very similar to the behavior of this collapsing suspension soil, for both the unperturbed and the perturbed phases of the material.

  20. Hydrodynamics of bacterial suspensions

    NASA Astrophysics Data System (ADS)

    Arlt, Jochen; Duncan, William J.; Poon, Wilson C. K.

    2005-08-01

    Suspensions of motile E. coli bacteria serve as a model system to experimentally study the hydrodynamics of active particle suspensions. Colloidal probe particles are localised within a suspension of motile bacteria by use of optical tweezers and their uctuations are monitored. The activity of the bacteria effects the fluctuations of the probe particles and their correlation, revealing information about the hydrodynamics of the suspension. We highlight experimental problems that make the interpretation of 'single probe' experiments (as reported before in literature) diffcult and present some preliminary results for 'dual probe' cross-correlation experiments.