Science.gov

Sample records for iter coil power

  1. Mechanical Analysis and Optimization of ITER Upper ELM Coil & Feeder

    NASA Astrophysics Data System (ADS)

    Zhang, Shanwen; Song, Yuntao; Wang, Zhongwei; Lu, Su; Ji, Xiang; Du, Shuangsong; Liu, Xufeng; Feng, Changle; Yang, Hong; Wang, Songke; Luo, Zhiren

    2014-08-01

    International thermonuclear experimental reactor (ITER) edge localized mode (ELM) coils are used to mitigate or suppress ELMs. The location of the coils in the vacuum vessel and behind the blankets exposes them to high radiation levels and high temperatures. The feeders provide the power and cooling water for ELM coils. They are located in the chimney ports and experience lower radiation and temperature levels. These coils and feeders work in a high magnetic field environment and are subjected to alternating electromagnetic force due to the interaction between high magnetic field and alternating current (AC) current in the coils. They are also subjected to thermal stresses due to thermal expansion. Using the ITER upper ELM coil and feeder as an example, mechanical analyses are performed to verify and optimize the updated design to enhance their structural performance. The results show that the conductor, jacket and bracket can meet the static, fatigue and crack threshold criteria. The optimization indicates that adding chamfers to the bracket can reduce the high stress of the bracket, and removing two rails can reduce the peak reaction force on the two rails arising from thermal expansion.

  2. Experiment of low resistance joints for the ITER correction coil.

    PubMed

    Liu, Huajun; Wu, Yu; Wu, Weiyue; Liu, Bo; Shi, Yi; Guo, Shuai

    2013-01-01

    A test method was designed and performed to measure joint resistance of the ITER correction coil (CC) in liquid helium (LHe) temperature. A 10 kA superconducting transformer was manufactured to provide the joints current. The transformer consisted of two concentric layer-wound superconducting solenoids. NbTi superconducting wire was wound in the primary coil and the ITER CC conductor was wound in the secondary coil. The primary and the secondary coils were both immersed in liquid helium of a 300 mm useful bore diameter cryostat. Two ITER CC joints were assembled in the secondary loop and tested. The current of the secondary loop was ramped to 9 kA in several steps. The two joint resistances were measured to be 1.2 nΩ and 1.65 nΩ, respectively.

  3. Axisymmetric Simulations of the ITER Vertical Stability Coil

    SciTech Connect

    Titus, Peter H.

    2013-07-09

    The ITER in-vessel coil system includes Vertical Stability (VS) coils and Edge Localized Mode (ELM) coils. There are two large VS ring coils, one upper and one lower. Each has four turns which are independently connected. The VS coils are needed for successful operation of ITER for most all of its operating modes. The VS coils must be highly reliable and fault tolerant. The operating environment includes normal and disruption Lorentz forces. To parametrically address all these design conditions in a tractable analysis requires a simplified model. The VS coils are predominately axisymmetric, and this suggests that an axisymmetric model can be meaningfully used to address the variations in mechanical design, loading, material properties, and time dependency. The axisymmetric finite element analysis described in this paper includes simulations of the bolted frictional connections used for the mounting details. Radiation and elastic-plastic response are modeled particularly for the extreme faulted conditions. Thermal connectivity is varied to study the effects of partial thermal connection of the actively cooled conductor to the remaining structure.

  4. ITER CENTRAL SOLENOID COIL INSULATION QUALIFICATION

    SciTech Connect

    Martovetsky, N N; Mann, T L; Miller, J R; Freudenberg, K D; Reed, R P; Walsh, R P; McColskey, J D; Evans, D

    2009-06-11

    An insulation system for ITER Central Solenoid must have sufficiently high electrical and structural strength. Design efforts to bring stresses in the turn and layer insulation within allowables failed. It turned out to be impossible to eliminate high local tensile stresses in the winding pack. When high local stresses can not be designed out, the qualification procedure requires verification of the acceptable structural and electrical strength by testing. We built two 4 x 4 arrays of the conductor jacket with two options of the CS insulation and subjected the arrays to 1.2 million compressive cycles at 60 MPa and at 76 K. Such conditions simulated stresses in the CS insulation. We performed voltage withstand tests and after end of cycling we measured the breakdown voltages between in the arrays. After that we dissectioned the arrays and studied micro cracks in the insulation. We report details of the specimens preparation, test procedures and test results.

  5. Design and Analysis of the ITER Vertical Stability Coils

    SciTech Connect

    Peter H. Titus, et. al.

    2012-09-06

    The ITER vertical stability (VS) coils have been developed through the preliminary design phase by Princeton Plasma Physics Laboratory (PPPL). Final design, prototyping and construction will be carried out by the Chinese Participant Team contributing lab, Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The VS coils are a part of the in-vessel coil systems which include edge localized mode (ELM) coils as well as the VS coils. An overview of the ELM coils is provided in another paper at this conference. 15 The VS design employs four turns of stainless steel jacketed mineral insulated copper (SSMIC) conductors The mineral insulation is Magnesium Oxide (MgO). Joule and nuclear heat is removed by water flowing at 3 m/s through the hollow copper conductor. A key element in the design is that slightly elevated temperatures in the conductor and its support spine during operation impose compressive stresses that mitigate fatigue damage. Away from joints, and break-outs, conductor thermal stresses are low because of the axisymmetry of the winding (there are no corner bends as in the ELM coils).The 120 degree segment joint, and break-out or terminal regions are designed with similar but imperfect constraint compared with the ring coil portion of the VS. The support for the break-out region is made from a high strength copper alloy, CuCrZr. This is needed to conduct nuclear heat to the actively cooled conductor and to the vessel wall. The support "spine" for the ring coil portion of the VS is 316 stainless steel, held to the vessel with preloaded 718 bolts. Lorentz loads resulting from normal operating loads, disruption loads and loads from disruption currents in the support spine shared with vessel, are applied to the VS coil. The transmission of the Lorentz and thermal expansion loads from the "spine" to the vessel rails is via friction augmented with a restraining "lip" to ensure the coil frictional slip is minimal and acceptable. Stresses in the coil

  6. DESIGN OF THE ITER IN-VESSEL COILS

    SciTech Connect

    Neumeyer, C; Bryant, L; Chrzanowski, J; Feder, R; Gomez, M; Heitzenroeder, P; Kalish, M; Lipski, A; Mardenfeld, M; Simmons, R; Titus, P; Zatz, I; Daly, E; Martin, A; Nakahira, M; Pillsbury, R; Feng, J; Bohm, T; Sawan, M; Stone, H; Griffiths, I; Schaffer, M

    2010-11-27

    The ITER project is considering the inclusion of two sets of in-vessel coils, one to mitigate the effect of Edge Localized Modes (ELMs) and another to provide vertical stabilization (VS). The in-vessel location (behind the blanket shield modules, mounted to the vacuum vessel inner wall) presents special challenges in terms of nuclear radiation (~3000 MGy) and temperature (100oC vessel during operations, 200oC during bakeout). Mineral insulated conductors are well suited to this environment but are not commercially available in the large cross section required. An R&D program is underway to demonstrate the production of mineral insulated (MgO or Spinel) hollow copper conductor with stainless steel jacketing needed for these coils. A preliminary design based on this conductor technology has been developed and is presented herein.

  7. Model coil for the international thermonuclear experimental reactor (ITER) magnet systems

    NASA Astrophysics Data System (ADS)

    Okuno, K.

    1994-07-01

    The model coil program for the ITER EDA includes the manufacture and testing of one Central Solenoid (CS) model coil and one Toroidal Field (TF) model coil, and test facility preparations. The CS model coil has an inner diameter of 1.6 m and produces a full field of 13 T. The TF model coil is race-track shaped with an outer dimension of 3 m x 4 m. It will be tested in conjunction with an LCT coil to simulate mechanical load conditions. Different kinds of conductors can be tested as inserts to be placed in the bore of the CS model coil. Two facilities at JAERI and KfK can provide ITER-relevant conditions for testing the model coils and inserts. The model coil program will validate the ITER magnet design and the manufacturing feasibility.

  8. Short initial length quench on CICC of ITER TF coils

    SciTech Connect

    Nicollet, S.; Ciazynski, D.; Duchateau, J.-L.; Lacroix, B.; Bessette, D.; Rodriguez-Mateos, F.; Coatanea-Gouachet, M.; Gauthier, F.

    2014-01-29

    Previous quench studies performed for the International Thermonuclear Experimental Reactor (ITER) Toroidal Field (TF) Coils have led to identify two extreme families of quench: first 'severe' quenches over long initial lengths in high magnetic field, and second smooth quenches over short initial lengths in low field region. Detailed analyses and results on smooth quench propagation and detectability on one TF Cable In Conduit Conductor (CICC) with a lower propagation velocity are presented here. The influence of the initial quench energy is shown and results of computations with either a Fast Discharge (FD) of the magnet or without (failure of the voltage quench detection system) are reported. The influence of the central spiral of the conductor on the propagation velocity is also detailed. In the cases of a regularly triggered FD, the hot spot temperature criterion of 150 K (with helium and jacket) is fulfilled for an initial quench length of 1 m, whereas this criterion is exceed (Tmax ≈ 200 K) for an extremely short length of 5 cm. These analyses were carried out using both the Supermagnet(trade mark, serif) and Venecia codes and the comparisons of the results are also discussed.

  9. In-Vessel Coil Material Failure Rate Estimates for ITER Design Use

    SciTech Connect

    L. C. Cadwallader

    2013-01-01

    The ITER international project design teams are working to produce an engineering design for construction of this large tokamak fusion experiment. One of the design issues is ensuring proper control of the fusion plasma. In-vessel magnet coils may be needed for plasma control, especially the control of edge localized modes (ELMs) and plasma vertical stabilization (VS). These coils will be lifetime components that reside inside the ITER vacuum vessel behind the blanket modules. As such, their reliability is an important design issue since access will be time consuming if any type of repair were necessary. The following chapters give the research results and estimates of failure rates for the coil conductor and jacket materials to be used for the in-vessel coils. Copper and CuCrZr conductors, and stainless steel and Inconel jackets are examined.

  10. Output beam analysis of high power COIL

    NASA Astrophysics Data System (ADS)

    Yu, Deli; Sang, Fengting; Jin, Yuqi; Sun, Yizhu

    2003-03-01

    As the output power of a chemical oxygen iodine laser (COIL) increases, the output laser beam instability appears as the far-field beam spot drift and deformation for the large Fresnel number unstable resonator. In order to interpret this phenomenon, an output beam mode simulation code was developed with the fast Fourier transform method. The calculation results show that the presence of the nonuniform gain in COIL produces a skewed output intensity distribution, which causes the mirror tilt and bulge due to the thermal expansion. With the output power of COIL increases, the mirror surfaces, especially the back surface of the scraper mirror, absorb more and more heat, which causes the drift and deformation of far field beam spot seriously. The initial misalignment direction is an important factor for the far field beam spot drifting and deformation.

  11. Design Analysis and Manufacturing Studies for ITER In-Vessel Coils

    SciTech Connect

    Kalish, M.; Heitzenroeder, P.; Neumeyer, C.; Titus, P.; Zhai, Y.; Zatz, I.; Messineo, M.; Gomez, M.; Hause, C.; Daly, E.; Martin, A.; Wu, Y.; Jin, J.; Long, F.; Song, Y.; Wang, Z.; Yun, Zan; Hsiao, J.; Pillsbury, J. R.; Bohm, T.; Sawan, M.; Jiang, NFN

    2014-07-01

    ITER is incorporating two types of In Vessel Coils (IVCs): ELM Coils to mitigate Edge Localized Modes and VS Coils to provide Vertical Stabilization of the plasma. Strong coupling with the plasma is required so that the ELM and VS Coils can meet their performance requirements. Accordingly, the IVCs are in close proximity to the plasma, mounted just behind the Blanket Shield Modules. This location results in a radiation and temperature environment that is severe necessitating new solutions for material selection as well as challenging analysis and design solutions. Fitting the coil systems in between the blanket shield modules and the vacuum vessel leads to difficult integration with diagnostic cabling and cooling water manifolds.

  12. Plasma response based RMP coil geometry optimization for an ITER plasma

    NASA Astrophysics Data System (ADS)

    Zhou, Lina; Liu, Yueqiang; Liu, Yue; Yang, Xu

    2016-11-01

    Based on an ITER 15MA Q  =  10 inductive scenario, a systematic numerical investigation is carried out in order to understand the effect of varying the geometry of the magnetic coils, used for controlling the edge localized modes in tokamaks, on the plasma response to the resonant magnetic perturbation (RMP) fields produced by these coils. Toroidal computations show that both of the plasma response based figures of merit—one is the pitch resonant radial field component near the plasma edge and the other is the plasma displacement near the X-point of the separatrix—consistently yield the same prediction for the optimal coil geometry. With a couple of exceptions, the presently designed poloidal location of the ITER upper and lower rows of RMP coils is close to the optimum, according to the plasma response based criteria. This holds for different coil current configurations with n  =  2, 3, 4, as well as different coil phasing between the upper and lower rows. The coils poloidal width from the present design, on the other hand, is sub-optimal for the upper and lower rows. Modelling also finds that the plasma response amplitude sharply decreases by moving the middle row RMP coils of ITER from the designed radial location (just inside the inner vacuum vessel) outwards (outside the outer vacuum vessel). The decay rate is sensitively affected by the middle row coils’ poloidal coverage for low-n (n  =  1, 2) RMP fields, but not for high-n (n  =  4) fields.

  13. Design considerations for ITER (International Thermonuclear Experimental Reactor) toroidal field coils

    SciTech Connect

    Kalsi, S.S.; Lousteau, D.C.; Miller, J.R.

    1987-01-01

    The International Thermonuclear Experimental Reactor (ITER) is a new tokamak design project with joint participation from Europe, Japan, the Union of Soviet Socialist Republics (USSR), and the United States. This paper describes a magnetic and mechanical design methodology for toroidal field (TF) coils that employs Nb/sub 3/Sn superconductor technology. Coil winding is sized by using conductor concepts developed for the US TIBER concept. The nuclear heating generated during operation is removed from the windings by helium flowing through the conductor. The heat in the coil case is removed through a separate cooling circuit operating at approximately 20 K. Manifold concepts are presented for the complete coil cooling system. Also included are concepts for the coil structural arrangement. The effects of in-plane and out-of-plane loads are included in the design considerations for the windings and case. Concepts are presented for reacting these loads with a minimum amount of additional structural material. Concepts discussed in this paper could be considered for the ITER TF coils. 6 refs., 5 figs., 1 tab.

  14. 3D vacuum magnetic field modelling of the ITER ELM control coil during standard operating scenarios

    NASA Astrophysics Data System (ADS)

    Evans, T. E.; Orlov, D. M.; Wingen, A.; Wu, W.; Loarte, A.; Casper, T. A.; Schmitz, O.; Saibene, G.; Schaffer, M. J.; Daly, E.

    2013-09-01

    In-vessel, non-axisymmetric, control coils have proven to be an important option for mitigating and suppressing edge-localized modes (ELMs) in high performance operating regimes on a growing number of tokamaks. Additionally, an in-vessel non-axisymmetric ELM control coil is being considered in the ITER baseline design. In preparing for the initial operation of this coil set, a comprehensive study was carried out to characterize the linear superposition of the 3D vacuum magnetic field, produced by the ELM coil, on a series of equilibria representing nine standard ITER operating scenarios. Here, the spatial phase angle of toroidally distributed currents, specified with a cosine waveform, in the upper and lower rows of the ITER ELM coil (IEC) set is varied in 2° steps while holding the current in the equatorial row of coils constant. The peak current in each of the three toroidal rows of window-frame coils making up the IEC is scanned between 5 kAt and 90 kAt in 5 kAt steps and the width of the edge region covered by overlapping vacuum field magnetic islands is calculated. This width is compared to a vacuum field ELM suppression correlation criterion found in DIII-D. A minimum coil current satisfying the DIII-D criterion, along with an associated set of phase angles, is identified for each ITER operating scenario. These currents range from 20 kAt to 75 kAt depending on the operating scenario being used and the toroidal mode number (n) of the cosine waveform. Comparisons between the scaling of the divertor footprint area in cases with n = 3 perturbation fields versus those with n = 4 show significant advantages when using n = 3. In addition, it is found that the DIII-D correlation criterion can be satisfied in the event that various combinations of individual IEC window-frame coils need to be turned off due to malfunctioning components located inside the vacuum vessel. Details of these results for both the full set of 27 window-frame coils and various reduced sets

  15. Radiation effects on the mechanical integrity of novel organic insulators for the ITER magnet coils

    NASA Astrophysics Data System (ADS)

    Bittner-Rohrhofer, K.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.; Fabian, P. E.; Munshi, N. A.

    2004-08-01

    High quality glass fiber reinforced composites will be used as electrical insulation systems for the windings of the superconducting magnet coils of the ITER fusion device. Recently, considerable interest in coil technology has focused on improving the radiation hardness of the organic impregnation resins, in order to avoid serious material damage, such as fiber-matrix debonding (delamination). This paper reports on first screening tests of novel cyanate-ester based glass fiber reinforced composites, which were developed especially for ITER-relevant applications. The material behavior was investigated at 77 K prior to and after reactor irradiation to a neutron fluence of 1 × 10 22 m -2 ( E>0.1 MeV) using the tensile and the short-beam-shear test, respectively. Furthermore, tension-tension fatigue measurements were carried out at low temperatures, in order to assess the mechanical performance under the pulsed operating conditions of ITER.

  16. Threshold power and energy confinement for ITER

    SciTech Connect

    Takizuka, T.

    1996-12-31

    In order to predict the threshold power for L-H transition and the energy confinement performance in ITER, assembling of database and analyses of them have been progressed. The ITER Threshold Database includes data from 10 divertor tokamaks. Investigation of the database gives a scaling of the threshold power of the form P{sub thr} {proportional_to} B{sub t} n{sub e}{sup 0.75} R{sup 2} {times} (n{sub e} R{sup 2}){sup +-0.25}, which predicts P{sub thr} = 100 {times} 2{sup 0{+-}1} MW for ITER at n{sub e} = 5 {times} 10{sup 19} m{sup {minus}3}. The ITER L-mode Confinement Database has also been expanded by data from 14 tokamaks. A scaling of the thermal energy confinement time in L-mode and ohmic phases is obtained; {tau}{sub th} {approximately} I{sub p} R{sup 1.8} n{sub e}{sup 0.4{sub P{sup {minus}0.73}}}. At the ITER parameter, it becomes about 2.2 sec. For the ignition in ITER, more than 2.5 times of improvement will be required from the L-mode. The ITER H-mode Confinement Database is expanded from data of 6 tokamaks to data of 11 tokamaks. A {tau}{sub th} scaling for ELMy H-mode obtained by a standard regression analysis predicts the ITER confinement time of {tau}{sub th} = 6 {times} (1 {+-} 0.3) sec. The degradation of {tau}{sub th} with increasing n{sub e} R{sup 2} (or decreasing {rho}{sub *}) is not found for ELMy H-mode. An offset linear law scaling with a dimensionally correct form also predicts nearly the same {tau}{sub th} value.

  17. Results of the international large coil task: a milestone for superconducting magnets in fusion power

    NASA Astrophysics Data System (ADS)

    Dresner, L.; Fietz, W. A.; Gauss, S.; Haubenreich, P. N.; Jakob, B.; Kato, T.; Komarek, P.; Lubell, M. S.; Lue, J. W.; Luton, J. N.; Maurer, W.; Okuno, K.; Schwenterly, S. W.; Shimamoto, S.; Takahashi, Y.; Ulbricht, A.; Vécsey, G.; Wüchner, F.; Zichy, J. A.

    The aim of the Large Coil Task (LCT) was to demonstrate the reliable operation of large superconducting toroidal field (TF) coils and to prove the design principles and fabrication techniques to be applied for the magnets in a tokamak experimental power reactor. This has been achieved by an outstanding international development effort during more than ten years of cooperation within an IEA agreement. Parties were the US DOE, EURATOM, JAERI and the Swiss government. Six different D-shaped test coils were separately designed, developed and constructed by the LCT participants, then extensively tested together in a compact toroidal array. The ORNL acted for DOE as the LCT operating agent, building and operating the required test facility. The US also provided three test coils; the other three participants one coil each. Detailed information on coil design and manufacture and all test data were shared among the LCT participants. After facility shakedown operations and preliminary coil tests, the full six-coil array tests were carried out in a continuous period from the beginning of 1986 until September 1987. Beside the originally planned tests to reach an 8 T design point performance, the tests went well beyond this goal, reaching 9 T peak field in each coil. The experiments also delineated the limits of operability and demonstrated the coil safety under abnormal conditions. For fusion application the transient a.c. field behaviour in the coils was also of great interest. Three of the coils have been tested in this respect and showed excellent performance, with loss values in agreement with the theoretical predictions. At the time of International Experimental Reactor (ITER) activities, it might be worthwhile to mention that LCT demonstrated an effective multinational collaboration in an advanced technology project, involving large scale hardware produced in several countries then assembled and operated as a tightly integrated system.

  18. First Test Results on ITER CS Model Coil and CS Insert

    SciTech Connect

    Martovetsky, N; Michael, P; Minervini, J; Radovinsky, A; Takayasu, M; Thome, R; Ando, T; Isono, T; Kato, T; Nakajima, H; Nishijima, G; Nunoya, Y; Sugimoto, M; Takahashi, Y; Tsuji, H; Bessette, D; Okuno, K; Ricci, M; Maix, R

    2000-10-12

    The Inner and Outer modules of the Central Solenoid Model Coil (CSMC) were built by US and Japanese home teams in collaboration with European and Russian teams to demonstrate the feasibility of a superconducting Central Solenoid for ITER and other large tokamak reactors. The CSMC mass is about 120 t, OD is about 3.6 m and the stored energy is 640 MJ at 46 kA and peak field of 13 T. Testing of the CSMC and the CS Insert took place at the Japan Atomic Energy Research Institute (JAERI) from mid March until mid August 2000. This paper presents the main results of the tests performed.

  19. European cryogenic material testing program for ITER coils and intercoil structures

    NASA Astrophysics Data System (ADS)

    Nyilas, A.; Portone, A.; Kiesel, H.

    2002-05-01

    The following materials were characterized for the use in the magnet structures of ITER: 1) Type 316LN cast materials having a modified chemistry used for a Model of the TF (Toroidal Field) outer intercoil structure were investigated with respect to tensile, fracture, fatigue crack growth rate (FCGR), and fatigue life behavior between 7 and 4 K. 2) For Type 316LN 80 mm thick plate used for the TFMC (T_oroidal F_ield M_odel C_oil) structure a complete cryogenic mechanical materials characterization was established. 3) For full size coil case mockups, repair weld properties of 240 mm thick narrow-gap welds were investigated to determine their tensile and fracture behavior. 4) For CSMC (C_enter S_olenoid M_odel C_oil) superconductor jackets, the fatigue lives of orbital butt welds made of Incoloy 908 and Type 316LN (aged and unaged) materials were determined up to one million cycles at 7 K. The results reveal to date that the FCGR of aged Type 316LN is inferior to Incoloy 908 material, whilst the fatigue life properties are comparable. However, for Type 316LN jacket structure considerable improvement of FCGR could be achieved by a solution heat treatment process. In addition, tensile and fatigue life tests performed with a new cryogenic mechanical test facility (630 kN capacity) are presented.

  20. Performance assessment and optimization of the ITER toroidal field coil joints

    NASA Astrophysics Data System (ADS)

    Rolando, G.; Foussat, A.; Knaster, J.; Ilin, Y.; Nijhuis, A.

    2013-08-01

    The ITER toroidal field (TF) system features eighteen coils that will provide the magnetic field necessary to confine the plasma. Each winding pack is composed of seven double pancakes (DP) connected through praying hands joints. Shaking hands joints are used to interface the terminals of the conductor with the feeder and inter-coil U-shaped bus bars. The feasibility of operating plasma scenarios depends on the ability of the magnets to retain sufficient temperature and current margins. In this respect, the joints represent a possible critical region due to the combination of steady state Joule heating in the resistance of the joint and coupling losses and currents in ramped operation. The temperature and current margins of both DP and terminal joints are analysed during the 15 and 17 MA plasma scenarios. The effect on the joint performance of feasible optimization solutions, such as rotation of the terminal joints and sole RRR increase, is explored. The characterization of the TF coil joints is completed by the estimation of the coupling loss time constant for different inter-strand and strand-to-joint resistance values. The study is carried out with the code JackPot-ACDC, allowing the analysis of lap-type joints with a strand-level detail.

  1. Power Supply Changes for NSTX Resistive Wall Mode Coils

    SciTech Connect

    Ramakrishnan, S S.

    2013-06-28

    The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. Prior to 2004, the NSTX power system was feeding twelve (12) circuits in the machine. In 2004 the Resistive Wall Mode (RWM) Coils were installed on the machine to correct error fields. There are six of these coils installed around the machine in the mid-plane. Since these coils need fast and accurate controls, a Switching Power Amplifier (SPA) with three sub-units was procured, installed and commissioned along with other power loop components. Two RWM Coils were connected in series and fed from one SPA sub-unit. After the initial RWM campaign, operational requirements evolved such that each of the RWM coils now requires separate power and control. Hence a second SPA with three sub-units has been procured and installed. The second unit is of improved design and has the controls and power components completely isolated. The existing thyristor rectifier is used as DC Link to both of the Switching Power Amplifiers. The controls for the RWM are integrated into the overall computer control of the DC Power systems for NSTX. This paper describes the design changes in the RWM Power system for NSTX.

  2. Diverse Power Iteration Embeddings and Its Applications

    SciTech Connect

    Huang H.; Yoo S.; Yu, D.; Qin, H.

    2014-12-14

    Abstract—Spectral Embedding is one of the most effective dimension reduction algorithms in data mining. However, its computation complexity has to be mitigated in order to apply it for real-world large scale data analysis. Many researches have been focusing on developing approximate spectral embeddings which are more efficient, but meanwhile far less effective. This paper proposes Diverse Power Iteration Embeddings (DPIE), which not only retains the similar efficiency of power iteration methods but also produces a series of diverse and more effective embedding vectors. We test this novel method by applying it to various data mining applications (e.g. clustering, anomaly detection and feature selection) and evaluating their performance improvements. The experimental results show our proposed DPIE is more effective than popular spectral approximation methods, and obtains the similar quality of classic spectral embedding derived from eigen-decompositions. Moreover it is extremely fast on big data applications. For example in terms of clustering result, DPIE achieves as good as 95% of classic spectral clustering on the complex datasets but 4000+ times faster in limited memory environment.

  3. EU contribution to the test and analysis of the ITER poloidal field conductor insert and the central solenoid model coil

    NASA Astrophysics Data System (ADS)

    Zanino, R.; Bagnasco, M.; Ciazynski, D.; Lacroix, B.; van Lanen, E. P. A.; Nicollet, S.; Nijhuis, A.; Savoldi Richard, L.; Sborchia, C.; Torre, A.; Vostner, A.; Zani, L.

    2009-08-01

    The PFCI is a single-layer solenoid wound from a 45 m long ITER-type NbTi dual-channel cable-in-conduit conductor, designed to be representative of the one currently proposed for the ITER PF1&6 coils. The PFCI, installed in the bore of the ITER central solenoid model coil (CSMC) at JAEA Naka, Japan, and well instrumented from both the thermal hydraulic and the electromagnetic points of view, has been successfully tested in June-August 2008. The test concentrated on DC performance (current sharing temperature and critical current measurements) and AC loss measurements. The results of the analysis of those measurements are reported in the paper, with particular attention to the comparison with the PFCI short sample, which was previously tested in the SULTAN facility. The evolution of the DC performance of the CSMC is also discussed.

  4. Theoretical design of gradient coils with minimum power dissipation: accounting for the discretization of current density into coil windings.

    PubMed

    While, Peter T; Korvink, Jan G; Shah, N Jon; Poole, Michael S

    2013-10-01

    Gradient coil windings are typically constructed from either variable width copper tracks or fixed width wires. Excessive power dissipation within these windings during gradient coil operation limits the maximum drive current or duty cycle of the coil. It is common to design gradient coils in terms of a continuous minimum power current density and to perform a discretization to obtain the locations of the coil tracks or wires. However, the existence of finite gaps between these conductors and a maximum conductor width leads to an underestimation of coil resistance when calculated using the continuous current density. Put equivalently, the actual current density within the tracks or wires is higher than that used in the optimization and this departure results in suboptimal coil designs. In this work, a mapping to an effective current density is proposed to account for these effects and provide the correct contribution to the power dissipation. This enables the design of gradient coils that are genuinely optimal in terms of power minimization, post-discretization. The method was applied to the theoretical design of a variety of small x- and z-gradient coils for use in small animal imaging and coils for human head imaging. Computer-driven comparisons were made between coils designed with and without the current density mapping, in terms of simulated power dissipation. For coils to be built using variable width tracks, the method provides slight reductions in power dissipation in most cases and substantial gains only in cases where the minimum separation between track centre-lines is less than twice the gap size. However, for coils to be built using fixed width wires, very considerable reductions in dissipated power are consistently attainable (up to 60%) when compared to standard approaches of coil optimization. PMID:23994605

  5. Iter

    NASA Astrophysics Data System (ADS)

    Iotti, Robert

    2015-04-01

    ITER is an international experimental facility being built by seven Parties to demonstrate the long term potential of fusion energy. The ITER Joint Implementation Agreement (JIA) defines the structure and governance model of such cooperation. There are a number of necessary conditions for such international projects to be successful: a complete design, strong systems engineering working with an agreed set of requirements, an experienced organization with systems and plans in place to manage the project, a cost estimate backed by industry, and someone in charge. Unfortunately for ITER many of these conditions were not present. The paper discusses the priorities in the JIA which led to setting up the project with a Central Integrating Organization (IO) in Cadarache, France as the ITER HQ, and seven Domestic Agencies (DAs) located in the countries of the Parties, responsible for delivering 90%+ of the project hardware as Contributions-in-Kind and also financial contributions to the IO, as ``Contributions-in-Cash.'' Theoretically the Director General (DG) is responsible for everything. In practice the DG does not have the power to control the work of the DAs, and there is not an effective management structure enabling the IO and the DAs to arbitrate disputes, so the project is not really managed, but is a loose collaboration of competing interests. Any DA can effectively block a decision reached by the DG. Inefficiencies in completing design while setting up a competent organization from scratch contributed to the delays and cost increases during the initial few years. So did the fact that the original estimate was not developed from industry input. Unforeseen inflation and market demand on certain commodities/materials further exacerbated the cost increases. Since then, improvements are debatable. Does this mean that the governance model of ITER is a wrong model for international scientific cooperation? I do not believe so. Had the necessary conditions for success

  6. Evaluation of inter-laminar shear strength of GFRP composed of bonded glass/polyimide tapes and cyanate-ester/epoxy blended resin for ITER TF coils

    SciTech Connect

    Hemmi, T.; Matsui, K.; Koizumi, N.; Nishimura, A.; Nishijima, S.; Shikama, T.

    2014-01-27

    The insulation system of the ITER TF coils consists of multi-layer glass/polyimide tapes impregnated a cyanate-ester/epoxy resin. The ITER TF coils are required to withstand an irradiation of 10 MGy from gamma-ray and neutrons since the ITER TF coils is exposed by fast neutron (>0.1 MeV) of 10{sup 22} n/m{sup 2} during the ITER operation. Cyanate-ester/epoxy blended resins and bonded glass/polyimide tapes are developed as insulation materials to realize the required radiation-hardness for the insulation of the ITER TF coils. To evaluate the radiation-hardness of the developed insulation materials, the inter-laminar shear strength (ILSS) of glass-fiber reinforced plastics (GFRP) fabricated using developed insulation materials is measured as one of most important mechanical properties before/after the irradiation in a fission reactor of JRR-3M. As a result, it is demonstrated that the GFRPs using the developed insulation materials have a sufficient performance to apply for the ITER TF coil insulation.

  7. Evaluation of inter-laminar shear strength of GFRP composed of bonded glass/polyimide tapes and cyanate-ester/epoxy blended resin for ITER TF coils

    NASA Astrophysics Data System (ADS)

    Hemmi, T.; Nishimura, A.; Matsui, K.; Koizumi, N.; Nishijima, S.; Shikama, T.

    2014-01-01

    The insulation system of the ITER TF coils consists of multi-layer glass/polyimide tapes impregnated a cyanate-ester/epoxy resin. The ITER TF coils are required to withstand an irradiation of 10 MGy from gamma-ray and neutrons since the ITER TF coils is exposed by fast neutron (>0.1 MeV) of 1022 n/m2 during the ITER operation. Cyanate-ester/epoxy blended resins and bonded glass/polyimide tapes are developed as insulation materials to realize the required radiation-hardness for the insulation of the ITER TF coils. To evaluate the radiation-hardness of the developed insulation materials, the inter-laminar shear strength (ILSS) of glass-fiber reinforced plastics (GFRP) fabricated using developed insulation materials is measured as one of most important mechanical properties before/after the irradiation in a fission reactor of JRR-3M. As a result, it is demonstrated that the GFRPs using the developed insulation materials have a sufficient performance to apply for the ITER TF coil insulation.

  8. Tryout of the vacuum impregnation procedure for the ITER PF1 coil on the VPI mold made of plastic shell

    NASA Astrophysics Data System (ADS)

    Grigoriev, S.; Rodin, I.; Tanchuk, V.; Korban, S.; Bursikov, A.; Mednikov, A.; Pugachev, A.

    2014-05-01

    The PF1 Coil as part of the ITER superconducting magnet system is intended for positioning and shaping of the magnetic poloidal field. The technical specification for the PF1 coil requires a full-scale simulation of the basic technological processes including vacuum pressure impregnation (VPI). Usually, a VPI mold is made of massive stainless steel walls to get the required quality of the monolithic structure of the pancake insulation by hot-curing compound. As a result, we obtain a high-cost furnace with a considerable amount of steel inside to be heated up to the specified temperature; excessive energy consumption for the furnace heating system; problems with the vacuum tightness of the VPI mold. The impregnation procedure using a VPI "plastic" mold was proposed so as to avoid the above mentioned shortcomings associated with the use of the furnace made of stainless steel.

  9. 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.

  10. Gas Evolution from Insulating Materials for Superconducting Coil of Iter by Gamma Ray Irradiation at Liquid Nitrogen Temperature

    NASA Astrophysics Data System (ADS)

    Idesaki, A.; Koizumi, N.; Sugimoto, M.; Morishita, N.; Ohshima, T.; Okuno, K.

    2008-03-01

    A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases evolved from the laminated material by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of gases evolved from the epoxy resin containing cyanate ester was about 60% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM).

  11. Variable frequency iteration MPPT for resonant power converters

    DOEpatents

    Zhang, Qian; Bataresh, Issa; Chen, Lin

    2015-06-30

    A method of maximum power point tracking (MPPT) uses an MPPT algorithm to determine a switching frequency for a resonant power converter, including initializing by setting an initial boundary frequency range that is divided into initial frequency sub-ranges bounded by initial frequencies including an initial center frequency and first and second initial bounding frequencies. A first iteration includes measuring initial powers at the initial frequencies to determine a maximum power initial frequency that is used to set a first reduced frequency search range centered or bounded by the maximum power initial frequency including at least a first additional bounding frequency. A second iteration includes calculating first and second center frequencies by averaging adjacent frequent values in the first reduced frequency search range and measuring second power values at the first and second center frequencies. The switching frequency is determined from measured power values including the second power values.

  12. NCSX Trim Coil Design

    SciTech Connect

    M. Kalish, A. Brooks, J. Rushinski, R. Upcavage

    2009-05-29

    The National Compact Stellarator Experiment (NCSX) was being constructed at the Princeton Plasma Physics Laboratory in partnership with Oak Ridge National Laboratory before work was stopped in 2008. The objective of this experiment was to develop the stellarator concept and evaluate it's potential as a model for future fusion power plants. Stellarator design requires very precisely positioned Modular Coils of complex shape to form 3D plasmas. In the design of NCSX, Trim Coils were required to compensate for both the positioning of the coils during assembly and the fabrication tolerances of the Modular Coils. Use of the Trim Coils allowed for larger tolerances increasing ease of assembly and decreasing overall cost. A set of Trim coils was developed to suppress the toroidal flux in island regions due to misalignment, magnetic materials, and eddy currents. The requirement imposed upon the design forced the toroidal flux in island regions below 10% of the total toroidal flux in the plasma. An analysis was first performed to evaluate candidate Trim Coil configurations iterating both the size, number, and position of the coils. The design was optimized considering both performance and cost while staying within the tight restraints presented by the space limited geometry. The final design of the Trim Coils incorporated a 48 Coil top bottom symmetric set. Fabrication costs were minimized by having only two coil types and using a planar conventional design with off the shelf commercial conductor. The Trim Coil design incorporated supports made from simple structural shapes assembled together in a way which allowed for adjustment as well as accommodation for the tolerance build up on the mating surfaces. This paper will summarize the analysis that led to the optimization of the Trim Coils set, the trim coil mechanical design, thermal and stress analysis, and the design of the supporting Trim Coil structure.

  13. Power Loss Analysis and Comparison of Segmented and Unsegmented Energy Coupling Coils for Wireless Energy Transfer

    PubMed Central

    Tang, Sai Chun; McDannold, Nathan J.

    2015-01-01

    This paper investigated the power losses of unsegmented and segmented energy coupling coils for wireless energy transfer. Four 30-cm energy coupling coils with different winding separations, conductor cross-sectional areas, and number of turns were developed. The four coils were tested in both unsegmented and segmented configurations. The winding conduction and intrawinding dielectric losses of the coils were evaluated individually based on a well-established lumped circuit model. We found that the intrawinding dielectric loss can be as much as seven times higher than the winding conduction loss at 6.78 MHz when the unsegmented coil is tightly wound. The dielectric loss of an unsegmented coil can be reduced by increasing the winding separation or reducing the number of turns, but the power transfer capability is reduced because of the reduced magnetomotive force. Coil segmentation using resonant capacitors has recently been proposed to significantly reduce the operating voltage of a coil to a safe level in wireless energy transfer for medical implants. Here, we found that it can naturally eliminate the dielectric loss. The coil segmentation method and the power loss analysis used in this paper could be applied to the transmitting, receiving, and resonant coils in two- and four-coil energy transfer systems. PMID:26640745

  14. Computation of the Mutual Inductance between Air-Cored Coils of Wireless Power Transformer

    NASA Astrophysics Data System (ADS)

    Anele, A. O.; Hamam, Y.; Chassagne, L.; Linares, J.; Alayli, Y.; Djouani, K.

    2015-09-01

    Wireless power transfer system is a modern technology which allows the transfer of electric power between the air-cored coils of its transformer via high frequency magnetic fields. However, due to its coil separation distance and misalignment, maximum power transfer is not guaranteed. Based on a more efficient and general model available in the literature, rederived mathematical models for evaluating the mutual inductance between circular coils with and without lateral and angular misalignment are presented. Rather than presenting results numerically, the computed results are graphically implemented using MATLAB codes. The results are compared with the published ones and clarification regarding the errors made are presented. In conclusion, this study shows that power transfer efficiency of the system can be improved if a higher frequency alternating current is supplied to the primary coil, the reactive parts of the coils are compensated with capacitors and ferrite cores are added to the coils.

  15. Qualification of a cyanate ester epoxy blend supplied by Japanese industry for the ITER TF coil insulation

    NASA Astrophysics Data System (ADS)

    Prokopec, R.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.; Knaster, J.; Savary, F.

    2012-06-01

    During the last years, two cyanate ester epoxy blends supplied by European and US industry have been successfully qualified for the ITER TF coil insulation. The results of the qualification of a third CE blend supplied by Industrial Summit Technology (IST, Japan) will be presented in this paper. Sets of test samples were fabricated exactly under the same conditions as used before. The reinforcement of the composite consists of wrapped R-glass / polyimide tapes, which are vacuum pressure impregnated with the resin. The mechanical properties of this material were characterized prior to and after reactor irradiation to a fast neutron fluence of 2×1022m-2 (E>0.1 MeV), i.e. twice the ITER design fluence. Static and dynamic tensile as well as static short beam shear tests were carried out at 77 K. In addition, stress strain relations were recorded to determine the Young's modulus at room temperature and at 77 K. The results are compared in detail with the previously qualified materials from other suppliers.

  16. Test and Analysis of China's First Short Conductor Sample for ITER Toroidal Field Coils

    NASA Astrophysics Data System (ADS)

    Liu, Bo; Wu, Yu

    2011-02-01

    In the framework of the ITER qualification tests, the first China TF conductor sample (CNTF1) was tested at the SULTAN facility. The sample was made of two TF conductor sections manufactured from identical internal stannum strands provided by the Oxford Superconducting technology company (OST). In order to evaluate the conductor performance, the current sharing temperature (Tcs) was measured at specified electromagnetic load cycling steps. Both conductor sections of the CNTF1 sample showed identical performance. Tcs was 7.2 K before cycling loading, and 6.9 K even after 950 cycles, without significant degradation, which substantially exceeds the ITER requirement of 5.7 K. The tests of the CNTF1 conductor sample showed that the electromagnetic cyclic load exhibited a negligible effect on the conductor performance. The coupling time constant θ for AC loss was 214 ms and 71.52 ms before and after the cycling load, respectively. The test results of the sample are compared with the strand performance and parameter model analysis.

  17. Analytical Model and Optimized Design of Power Transmitting Coil for Inductively Coupled Endoscope Robot.

    PubMed

    Ke, Quan; Luo, Weijie; Yan, Guozheng; Yang, Kai

    2016-04-01

    A wireless power transfer system based on the weakly inductive coupling makes it possible to provide the endoscope microrobot (EMR) with infinite power. To facilitate the patients' inspection with the EMR system, the diameter of the transmitting coil is enlarged to 69 cm. Due to the large transmitting range, a high quality factor of the Litz-wire transmitting coil is a necessity to ensure the intensity of magnetic field generated efficiently. Thus, this paper builds an analytical model of the transmitting coil, and then, optimizes the parameters of the coil by enlarging the quality factor. The lumped model of the transmitting coil includes three parameters: ac resistance, self-inductance, and stray capacitance. Based on the exact two-dimension solution, the accurate analytical expression of ac resistance is derived. Several transmitting coils of different specifications are utilized to verify this analytical expression, being in good agreements with the measured results except the coils with a large number of strands. Then, the quality factor of transmitting coils can be well predicted with the available analytical expressions of self- inductance and stray capacitance. Owing to the exact estimation of quality factor, the appropriate coil turns of the transmitting coil is set to 18-40 within the restrictions of transmitting circuit and human tissue issues. To supply enough energy for the next generation of the EMR equipped with a Ø9.5×10.1 mm receiving coil, the coil turns of the transmitting coil is optimally set to 28, which can transfer a maximum power of 750 mW with the remarkable delivering efficiency of 3.55%. PMID:26292335

  18. 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.

  19. Multi-coil approach to reduce electromagnetic energy absorption for wirelessly powered implants

    PubMed Central

    Lazzi, Gianluca

    2014-01-01

    Near-field inductive coupling is a commonly used technique for wireless power transfer (WPT) in biomedical implants. Owing to the close proximity of the implant coil(s) with the tissue ( ∼1 mm) and high current ( ∼100–300 mA) in the magnetic coil(s), a significant induced electric field can be generated for the operating frequency (1–20 MHz). In this Letter, a multi-coil-based WPT technique is proposed to selectively control the currents in the external and implant coils to reduce the specific absorption rate (SAR). A three-coil WPT system, that can achieve 26% reduction in peak 1-g SAR and 15% reduction in peak 10-g SAR, as compared to a two-coil WPT system with the same dimensions, is implemented and used to demonstrate the effectiveness of the proposed approach. To achieve the seamless design for the external and implant electronics, the multi-coil system achieves the same voltage gain and bandwidth as the two-coil design with 46% improvement in the power transfer efficiency.

  20. Vehicle to wireless power transfer coupling coil alignment sensor

    DOEpatents

    Miller, John M.; Chambon, Paul H.; Jones, Perry T.; White, Clifford P.

    2016-02-16

    A non-contacting position sensing apparatus includes at least one vehicle-mounted receiver coil that is configured to detect a net flux null when the vehicle is optimally aligned relative to the primary coil in the charging device. Each of the at least one vehicle-mounted receiver coil includes a clockwise winding loop and a counterclockwise winding loop that are substantially symmetrically configured and serially connected to each other. When the non-contacting position sensing apparatus is located directly above the primary coil of the charging device, the electromotive forces from the clockwise winding loop and the counterclockwise region cancel out to provide a zero electromotive force, i.e., a zero voltage reading across the coil that includes the clockwise winding loop and the counterclockwise winding loop.

  1. Optimal position of the transmitter coil for wireless power transfer to the implantable device.

    PubMed

    Jinghui Jian; Stanaćević, Milutin

    2014-01-01

    The maximum deliverable power through inductive link to the implantable device is limited by the tissue exposure to the electromagnetic field radiation. By moving away the transmitter coil from the body, the maximum deliverable power is increased as the magnitude of the electrical field at the interface with the body is kept constant. We demonstrate that the optimal distance between the transmitter coil and the body is on the order of 1 cm when the current of the transmitter coil is limited to 1 A. We also confirm that the conditions on the optimal frequency of the power transmission and the topology of the transmission coil remain the same as if the coil was directly adjacent to the body. PMID:25571496

  2. Design and preliminary tests of a twin coil HTS SMES for pulse power operation

    NASA Astrophysics Data System (ADS)

    Badel, Arnaud; Tixador, Pascal; Berger, Kevin; Deleglise, Marc

    2011-05-01

    The design of a twin coil 2 × 200 kJ-1 MW pulse power high temperature superconductor (HTS) superconducting magnetic energy storage (SMES) demonstrator is presented. Its aim is to test at small scale various possibilities of electromagnetic launcher powering. The foreseen operation modes include high voltage discharge in power capacitors, sequential discharges of identical energies from two coupled coils, and XRAM current multiplication. Special attention was paid to the arrangement of the coils for the energies discharged to be equal. The coils are cooled by conduction from three cryocoolers; the thermal design was optimized in order to maintain the coils around 15 K in spite of the high number of current leads required for XRAM operation (eight). Preliminary tests of the demonstrator are also presented, showing that the thermal and electrical characteristics are in very good agreement with the design objectives.

  3. Power handling of the JET ITER-like wall

    NASA Astrophysics Data System (ADS)

    Arnoux, G.; Balboa, I.; Clever, M.; Devaux, S.; De Vries, P.; Eich, T.; Firdaouss, M.; Jachmich, S.; Lehnen, M.; Lomas, P. J.; Matthews, G. F.; Mertens, Ph; Nunes, I.; Riccardo, V.; Ruset, C.; Sieglin, B.; Valcárcel, D. F.; Wilson, J.; Zastrow, K.-D.; contributors, JET-EFDA

    2014-04-01

    The ITER-like wall (ILW) at JET provides a unique opportunity to study the combination of material (beryllium and tungsten) that will be used for the plasma facing components (PFCs) in ITER. Both the limiters (Be) and divertor (CFC W coated and bulk W) have been designed to maximize their power handling capability. During the last experimental campaign (October 2010-July 2011) this capability has been assessed and even challenged in the case of the Be wall. The Be limiters' power handling capability (19 MW m-2 s-1/2), predicted with a simple model, has been proven to be robust by the experiments despite an unexpected power load pattern. This capability has been pushed to its limit leading to Be melt events, which revealed that the power load is toroidally asymmetric. The protection system of the ILW did not prevent melt events mainly because the protection strategy relies on the assumption that the power load is toroidally symmetric. The bulk W divertor target performed as predicted. Operations were constrained by: (i) an energy load limit (60 MJ m-2) (ii) the limited number of cycles of the surface temperature above 1200 °C in order to prevent thermal fatigue. This latter limit has been exceeded about 300 times and no signs of damage or thermal fatigue have been observed by the photogrammetric survey.

  4. 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.

  5. 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. PMID:25571390

  6. Thermoelectric power of supported graphene - An iterative approach

    SciTech Connect

    Rizwana Begum, K.; Sankeshwar, N. S.

    2015-06-24

    Thermoelectric power, S, of graphene supported on SiO{sub 2} substrate is studied for 10K < T < 400K within the framework of Boltzmann transport formalism by an iterative method. Numerical calculations of diffusion thermopower, S{sub d}, as a function of temperature, are presented assuming the electrons to be scattered by impurities, vacancies, surface roughness, acoustic phonons, inelastic optical phonons and surface polar optical phonons. For the range of temperatures considered, S{sub d} is found to be dominated by impurities for T < 40K and by acoustic phonon and vacancy scatterings for T > 40K. The optical phonons are found to influence S{sub d} for T > 300K. Our calculations, assuming the drag component to be negligible, obtain good agreement with the recent experimental data.

  7. Performance evaluation of power transmission coils for powering endoscopic wireless capsules.

    PubMed

    Basar, Md Rubel; Ahmad, Mohd Yazed; Cho, Jongman; Ibrahim, Fatimah

    2015-01-01

    This paper presents an analysis of H-field generated by a simple solenoid, pair of solenoids, pair of double-layer solenoids, segmented-solenoid, and Helmholtz power transmission coils (PTCs) to power an endoscopic wireless capsule (WC). The H-fields were computed using finite element analysis based on partial differential equations. Three parameters were considered in the analysis: i) the maximum level of H-field (Hmax) to which the patient's body would be exposed, ii) the minimum level of H-field (Hmin) effective for power transmission, and iii) uniformity of H-field. We validated our analysis by comparing the computed data with data measured from a fabricated Helmholtz PTC. This analysis disclosed that at the same excitation power, all the PTCs are able to transfer same amount of minimum usable power since they generated almost equal value of Hmin. The level of electromagnetic exposure and power transfer stability across all the PTCs would vary significantly which is mainly due to the different level of Hmax and H-field uniformity. The segmented solenoid PTC would cause the lowest exposure and this PTC can transfer the maximum amount of power. The Helmholtz PTC would be able to transfer the most stable power with a moderate level of exposure. PMID:26736743

  8. Planar micro-nano-coils for electrically driving liquid crystal microlenses based on wireless power transmission

    NASA Astrophysics Data System (ADS)

    Chen, Cheng; Hu, Wei; Luo, Jun; Lei, Yu; Tong, Qing; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2015-12-01

    In this paper, the planar micro-nano-coils (PMNCs) with diverse planar spiral structures are designed for electrically driving and controlling liquid crystal microlenses (LCMs) based on wireless power transmission approaches. The PMNCs with different basic shapes are fabricated, including typical micro-triangle, micro-square, micro-pentagon, micro-hexagon, and micro-circle. According to the designed microstructures, using loop iterative approximation means based on Greenhouse algorithm, the inductance values of the microcoils can be calculated through combining self-inductance with mutual-inductance. In experiments, both the wet and dry etching technologies are adapted to obtain the desired PMNCs over aluminum-coated glass substrates. The etching technologies utilized by us are implemented on initial glass substrates spread by photoresist mask, which has been processed by common ultraviolet lithography. And the wet and dry etching technologies are different in the way of eroding aluminum film. Usually, the wet etching is a kind of the chemical reaction of alkali element in the developing liquid used, but the dry etching is a type of physical etching process such as the ion beam etching so as to fabricate microstructures with smaller size than that of wet etching. After the fabrication of the PMNCs, the electrical testing circuit for the inductance of the PMNCs is built to obtain their actual inductance values. By comparing inductances with theoretical prediction, the improved PMNCs are proposed for driving and controlling LCMs, which demonstrates enhanced light transmission efficiency of the PMNCs, and makes it more efficient to adjust LCMs developed by us.

  9. Geometry-based optimization of radio-frequency coils for powering neuroprosthetic implants.

    PubMed

    Kim, Jungsuk; Basham, Eric; Pedrotti, Kenneth D

    2013-02-01

    Biomedical implants powered by inductive links have several advantages over batteries or percutaneous power linkages. The inductive link power transfer efficiency must be optimized to realize the full advantage over other power delivery technologies. Optimization is also important to reduce the electromagnetic radiation exposure, reduce secondary heating effects and improve power efficiency, so that large primary side storage batteries are not required. Geometric constraints, i.e., size and shape, of biomedical implants are a primary concern of device design. In this paper, we present a novel coil optimization strategy driven by geometric constraints. By considering the relationship between wire diameter, number of turns, quality factor, coupling coefficient and shape of coil, we can optimize the inductively coupled coils to maximize the power transfer efficiency under stringent geometric constraints. This new approach is verified using a design example targeted for an intraocular visual prosthesis. In this example, we demonstrate an experimental power transfer efficiency of 52% by co-optimization of the primary and secondary coils. PMID:23086205

  10. Core fusion power gain and alpha heating in JET, TFTR, and ITER

    NASA Astrophysics Data System (ADS)

    Budny, R. V.; Cordey, J. G.; TFTR Team; Contributors, JET

    2016-05-01

    Profiles of the ratio of fusion power and the auxiliary heating power q DT are calculated for the TFTR and JET discharges with the highest neutron emission rates, and are predicted for ITER. Core values above 1.3 for JET and 0.8 for TFTR are obtained. Values above 20 are predicted for ITER baseline plasmas.

  11. 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. PMID:22255221

  12. Alternative power supply and dump resistor connections for similar, mutally coupled, superconducting coils

    SciTech Connect

    Owen, E.W.; Shimer, D.W.; Wang, S.T.

    1983-11-30

    Alternative methods of connecting similar mutually coupled coils to their power supplies and dump resistors are investigated. The circuits are evaluated for both operating and fault conditions. The factors considered are the voltage to ground during a dump, short circuits, open circuits, quenches, and failure of the protection system to detect a quench. Of particular interest are the currents induced in coils that remain superconducting when one or more coils quench. The alternative connections include combined power supplies, individual dump resistors, combined resistors and series and parallel dump resistors. A new circuit that contains coupling resistors is proposed. The coupling resistors do not affect normal fast dumps but reduce the peak induced currents while also reducing the energy rating of the dump resistors. Another novel circuit, the series circuit with diodes, is discussed. The MFTF-B central-cell solenoids are used as an example.

  13. Wirelessly powered electrowetting-on-dielectric (EWOD) by planar receiver coils

    NASA Astrophysics Data System (ADS)

    Byun, Sang Hyun; Yuan, Junqi; Yoon, Myung Gon; Cho, Sung Kwon

    2015-03-01

    Electrowetting-on-dielectric (EWOD) is one of the most versatile methods used to control the wettability of liquids using electrical input. In most applications, EWOD is applied using physical wiring, which may restrict its application to implantable EWOD devices. In order to resolve this issue, we have studied and developed a wirelessly powered EWOD by using planar coils at the receiver that are fabricated out of a printed circuit board (PCB) by means of standard micro photolithography. Unlike conventional, bulky, spool coil type, the planar coil type lends itself to compact design and easy integration with EWOD chips. The present wireless powering principle is based on magnetic induction, which is very efficient when the transmitter and receiver coils are close to each other. The voltage obtained at the receiver is much higher than typically required EWOD voltages (>50 V) using a high transmission frequency (~MHz). The span of the EWOD contact angle is over 40°. In addition, amplitude modulation (AM) is implemented in the present wireless powering setup, followed by demodulation, in order to oscillate droplets at low frequency. This technique ensures smooth and reliable droplet movements. The wirelessly powered EWOD is used to transport a droplet and is mounted in a mini-boat which it powers and propels.

  14. 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. PMID:25808086

  15. Anisotropic metamaterial for efficiency enhancement of mid-range wireless power transfer under coil misalignment

    NASA Astrophysics Data System (ADS)

    Ranaweera, A. L. A. K.; Arriola Moscoso, Carlos; Lee, Jong-Wook

    2015-11-01

    In a wireless power transfer (WPT) system, misalignment between transmitter and receiver coils is one of the key factors affecting efficiency. Recently, metamaterials have shown great potential to enhance electromagnetic propagation in various environments. In this work, we apply a metamaterial to enhance the WPT in a more general environment where misalignment is considered. Using an anisotropic metamaterial, we obtain a significant efficiency enhancement. Therefore, we propose that the metamaterial is an effective means to mitigate the decreased efficiency caused by misalignment. In addition, we investigate the effect of coil misalignment on the threshold distance beyond which the metamaterial enhances the performance of WPT.

  16. INVESTIGATION OF A TEST LOOP FOR THE COOLING SYSTEM OF THE ITER TF COIL UNDER PULSED HEAT LOAD

    SciTech Connect

    Rousset, B.; Girard, A.; Maze, S.; Poncet, J. M.; Roussel, P.; Murdoch, D.; Sanmarti, M.

    2008-03-16

    CEA is involved in the design of the cooling scheme of the future ITER tokamak. Pulsed operation of ITER will result in heat load variations (which refrigerators have difficulties to cope with). A load smoothing device has been proposed by the ITER team which needs to be validated. To do this, a scaled-down experiment (hereafter also called model) has been proposed and studied in the framework of an EFDA sub-task. This paper presents the test loop dimensioning and the preliminary design for constructing the model. The choice of the relevant design criteria had to be defined so as to obtain in fine a geometric ratio between the ITER system and the model. It is shown that this ratio is then applicable for the mass flow rates as well as the different volumes (heat exchanger, pipes,...) existing on ITER and on the proposed experimental model. Details of the scaling, model design and 3D views corresponding to this preliminary study are presented in this paper.

  17. Power generation from human body motion through magnet and coil arrays with magnetic spring

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Yufeng; Kim, Eun Sok

    2014-02-01

    This article presents a hand-held electromagnetic energy harvester which can be used to harvest tens of mW power level from human body motion. A magnet array, aligned to a coil array for maximum magnetic flux change, is suspended by a magnetic spring for a resonant frequency of several Hz and is stabilized horizontally by graphite sheets for reducing the friction. An analytical model of vibration-driven energy harvester with magnetic spring through magnet and coil arrays is developed to explore the power generation from vibrations at low frequency and large amplitude. When the energy harvester (occupying 120 cc and weighing 180 g) is placed in a backpack of a human walking at various speeds, the power output increases as the walking speed increases from 0.45 m/s (slow walking) to 3.58 m/s (slow running), and reaches 32 mW at 3.58 m/s.

  18. High-power COIL fiber transmission for D&D application

    NASA Astrophysics Data System (ADS)

    Gruenewald, Karin M.; Bohn, Willy L.; Duschek, Frank R.; Handke, Juergen; Schall, Wolfgang O.

    2004-06-01

    11 kW of COIL power are successfully transmitted through a 20 meter long modified commercial fiber system with optical losses below 10%. The transmission ratio is derived from simultaneous measurement of the laser output power behind the total reflector and the transmitted laser power behind the complete optical fiber system. The fiber delivery system is used to demonstrate cutting of various materials pertinent to dismantling & decommissioning of nuclear installations. Nitrogen and oxygen gas assisted cuts are performed for metal and nonmetal samples, which are made of steel, aluminum, concrete and graphite. The cutting results are validated with theoretical models from literature. The COIL cutting performance is compared to referenced data of laser materials processing.

  19. Power Radiated from ITER and CIT by Impurities

    DOE R&D Accomplishments Database

    Cummings, J.; Cohen, S. A.; Hulse, R.; Post, D. E.; Redi, M. H.; Perkins, J.

    1990-07-01

    The MIST code has been used to model impurity radiation from the edge and core plasmas in ITER and CIT. A broad range of parameters have been varied, including Z{sub eff}, impurity species, impurity transport coefficients, and plasma temperature and density profiles, especially at the edge. For a set of these parameters representative of the baseline ITER ignition scenario, it is seen that impurity radiation, which is produced in roughly equal amounts by the edge and core regions, can make a major improvement in divertor operation without compromising core energy confinement. Scalings of impurity radiation with atomic number and machine size are also discussed.

  20. Power radiated from ITER and CIT by impurities

    SciTech Connect

    Cummings, J.; Cohen, S.A.; Hulse, R.; Post, D.E.; Redi, M.H.; Perkins, J.

    1990-07-01

    The MIST code has been used to model impurity radiation from the edge and core plasmas in ITER and CIT. A broad range of parameters have been varied, including Z{sub eff}, impurity species, impurity transport coefficients, and plasma temperature and density profiles, especially at the edge. For a set of these parameters representative of the baseline ITER ignition scenario, it is seen that impurity radiation, which is produced in roughly equal amounts by the edge and core regions, can make a major improvement in divertor operation without compromising core energy confinement. Scalings of impurity radiation with atomic number and machine size are also discussed. 22 refs., 16 figs.

  1. Radiofrequency Energy Deposition and Radiofrequency Power Requirements in Parallel Transmission with Increasing Distance from the Coil to the Sample

    PubMed Central

    Deniz, Cem M.; Vaidya, Manushka V.; Sodickson, Daniel K.; Lattanzi, Riccardo

    2015-01-01

    Purpose We investigated global specific absorption rate (SAR) and radiofrequency (RF) power requirements in parallel transmission as the distance between the transmit coils and the sample was increased. Methods We calculated ultimate intrinsic SAR (UISAR), which depends on object geometry and electrical properties but not on coil design, and we used it as the reference to compare the performance of various transmit arrays. We investigated the case of fixing coil size and increasing the number of coils while moving the array away from the sample, as well as the case of fixing coil number and scaling coil dimensions. We also investigated RF power requirements as a function of liftoff, and tracked local SAR distributions associated with global SAR optima. Results In all cases, the target excitation profile was achieved and global SAR (as well as associated maximum local SAR) decreased with lift-off, approaching UISAR, which was constant for all lift-offs. We observed a lift-off value that optimizes the balance between global SAR and power losses in coil conductors. We showed that, using parallel transmission, global SAR can decrease at ultra high fields for finite arrays with a sufficient number of transmit elements. Conclusion For parallel transmission, the distance between coils and object can be optimized to reduce SAR and minimize RF power requirements associated with homogeneous excitation. PMID:25752250

  2. Design of double layer printed spiral coils for wirelessly-powered biomedical implants.

    PubMed

    Ashoori, Ehsan; Asgarian, Farzad; Sodagar, Amir M; Yoon, Euisik

    2011-01-01

    In this paper employing double layer printed spiral coils (PSCs) is proposed for wireless power transmission in implantable biomedical applications. Detailed modeling of this type of PSCs is presented. Both calculations and measurements of fabricated double layer PSCs indicate that this structure can decrease the size of typical single layer PSCs without any change in the most important parameters of the coils, such as quality factor. Also, it is shown that with equal PSC dimensions and design parameters, double layer PSCs achieve significantly higher inductances and quality factors. Ultimately, a pair of double layer PSCs with a distance of 5 mm in air is used in an inductive link. The power transfer efficiency of this link is about 79.8% with a carrier frequency of 5 MHz and coupling coefficient of 0.189. PMID:22254943

  3. Design of double layer printed spiral coils for wirelessly-powered biomedical implants.

    PubMed

    Ashoori, Ehsan; Asgarian, Farzad; Sodagar, Amir M; Yoon, Euisik

    2011-01-01

    In this paper employing double layer printed spiral coils (PSCs) is proposed for wireless power transmission in implantable biomedical applications. Detailed modeling of this type of PSCs is presented. Both calculations and measurements of fabricated double layer PSCs indicate that this structure can decrease the size of typical single layer PSCs without any change in the most important parameters of the coils, such as quality factor. Also, it is shown that with equal PSC dimensions and design parameters, double layer PSCs achieve significantly higher inductances and quality factors. Ultimately, a pair of double layer PSCs with a distance of 5 mm in air is used in an inductive link. The power transfer efficiency of this link is about 79.8% with a carrier frequency of 5 MHz and coupling coefficient of 0.189.

  4. Development of effective power supply using electric double layer capacitor for static magnetic field coils in fusion plasma experiments.

    PubMed

    Inomoto, M; Abe, K; Yamada, T; Kuwahata, A; Kamio, S; Cao, Q H; Sakumura, M; Suzuki, N; Watanabe, T; Ono, Y

    2011-02-01

    A cost-effective power supply for static magnetic field coils used in fusion plasma experiments has been developed by application of an electric double layer capacitor (EDLC). A prototype EDLC power supply system was constructed in the form of a series LCR circuit. Coil current of 100 A with flat-top longer than 1 s was successfully supplied to an equilibrium field coil of a fusion plasma experimental apparatus by a single EDLC module with capacitance of 30 F. The present EDLC power supply has revealed sufficient performance for plasma confinement experiments whose discharge duration times are an order of several seconds. PMID:21361590

  5. Dryout occurrence in a helically coiled steam generator for nuclear power application

    NASA Astrophysics Data System (ADS)

    Santini, L.; Cioncolini, A.; Lombardi, C.; Ricotti, M.

    2014-03-01

    Dryout phenomena have been experimentally investigated in a helically coiled steam generator tube. The experiences carried out in the present work are part of a wide experimental program devoted to the study of a GEN III+ innovative nuclear power plant [1].The experimental facility consists in an electrically heated AISI 316L stainless steel coiled tube. The tube is 32 meters long, 12.53 mm of inner diameter, with a coil diameter of 1m and a pitch of 0.79 m, resulting in a total height of the steam generator of 8 meters. The thermo-hydraulics conditions for dryout investigations covered a spectrum of mass fluxes between 199 and 810 kg/m2s, the pressures ranges from 10.7 to 60.7 bar, heat fluxes between 43.6 to 209.3 kW/m2.Very high first qualities dryout, between 0.72 and 0.92, were found in the range of explored conditions, comparison of our results with literature available correlations shows the difficulty in predicting high qualities dryout in helical coils., immediately following the heading. The text should be set to 1.15 line spacing. The abstract should be centred across the page, indented 15 mm from the left and right page margins and justified. It should not normally exceed 200 words.

  6. HIGH-POWER TURBODRILL AND DRILL BIT FOR DRILLING WITH COILED TUBING

    SciTech Connect

    Robert Radtke; David Glowka; Man Mohan Rai; David Conroy; Tim Beaton; Rocky Seale; Joseph Hanna; Smith Neyrfor; Homer Robertson

    2008-03-31

    Commercial introduction of Microhole Technology to the gas and oil drilling industry requires an effective downhole drive mechanism which operates efficiently at relatively high RPM and low bit weight for delivering efficient power to the special high RPM drill bit for ensuring both high penetration rate and long bit life. This project entails developing and testing a more efficient 2-7/8 in. diameter Turbodrill and a novel 4-1/8 in. diameter drill bit for drilling with coiled tubing. The high-power Turbodrill were developed to deliver efficient power, and the more durable drill bit employed high-temperature cutters that can more effectively drill hard and abrasive rock. This project teams Schlumberger Smith Neyrfor and Smith Bits, and NASA AMES Research Center with Technology International, Inc (TII), to deliver a downhole, hydraulically-driven power unit, matched with a custom drill bit designed to drill 4-1/8 in. boreholes with a purpose-built coiled tubing rig. The U.S. Department of Energy National Energy Technology Laboratory has funded Technology International Inc. Houston, Texas to develop a higher power Turbodrill and drill bit for use in drilling with a coiled tubing unit. This project entails developing and testing an effective downhole drive mechanism and a novel drill bit for drilling 'microholes' with coiled tubing. The new higher power Turbodrill is shorter, delivers power more efficiently, operates at relatively high revolutions per minute, and requires low weight on bit. The more durable thermally stable diamond drill bit employs high-temperature TSP (thermally stable) diamond cutters that can more effectively drill hard and abrasive rock. Expectations are that widespread adoption of microhole technology could spawn a wave of 'infill development' drilling of wells spaced between existing wells, which could tap potentially billions of barrels of bypassed oil at shallow depths in mature producing areas. At the same time, microhole coiled tube

  7. Artificial Neural Networks: a viable tool to design heat load smoothing strategies for the ITER Toroidal Field coils

    NASA Astrophysics Data System (ADS)

    Froio, A.; Bonifetto, R.; Carli, S.; Quartararo, A.; Savoldi, L.; Zanino, R.

    2015-12-01

    In superconducting tokamaks, cryoplants provide the helium needed to cool the superconducting magnet systems. The evaluation of the heat load from the magnets to the cryoplant is fundamental for the design of the latter and the assessment of suitable strategies to smooth the heat load pulses induced by the pulsed plasma scenarios is crucial for the operation. Here, a simplified thermal-hydraulic model of an ITER Toroidal Field (TF) magnet, based on Artificial Neural Networks (ANNs), is developed and inserted into a detailed model of the ITER TF winding and casing cooling circuits based on the state-of-the-art 4C code, which also includes active controls. The low computational effort requested by such a model allows performing a fast parametric study, to identify the best smoothing strategy during standard plasma operation. The ANNs are trained using 4C simulations, and the predictive capabilities of the simplified model are assessed against 4C simulations, both with and without active smoothing, in terms of accuracy and computational time.

  8. A study on the operation analysis of the power conditioning system with real HTS SMES coil

    NASA Astrophysics Data System (ADS)

    Kim, A. R.; Jung, H. Y.; Kim, J. H.; Ali, Mohd. Hasan; Park, M.; Yu, I. K.; Kim, H. J.; Kim, S. H.; Seong, K. C.

    2008-09-01

    Voltage sag from sudden increasing loads is one of the major problems in the utility network. In order to compensate the voltage sag problem, power compensation devices have widely been developed. In the case of voltage sag, it needs an energy source to overcome the energy caused by voltage sag. According as the SMES device is characterized by its very high response time of charge and discharge, it has widely been researched and developed for more than 20 years. However, before the installation of SMES into utility, the system analysis has to be carried out with a certain simulation tool. This paper presents a real-time simulation algorithm for the SMES system by using the miniaturized SMES model coil whose properties are same as those of real size SMES coil. With this method, researchers can easily analyse the performance of SMES connected into utility network by abstracting the properties from the real modeled SMES coil and using the virtual simulated power network in RSCAD/RTDS.

  9. Synchronous Generator with HTS-2G field coils for Windmills with output power 1 MW

    NASA Astrophysics Data System (ADS)

    Kovalev, K.; Kovalev, L.; Poltavets, V.; Samsonovich, S.; Ilyasov, R.; Levin, A.; Surin, M.

    2014-05-01

    Nowadays synchronous generators for wind-mills are developed worldwide. The cost of the generator is determined by its size and weight. In this deal the implementation of HTS-2G generators is very perspective. The application of HTS 2G field coils in the rotor allows to reduce the size of the generator is 1.75 times. In this work the design 1 MW HTS-2G generator is considered. The designed 1 MW HTS-2G generator has the following parameters: rotor diameter 800 mm, active length 400 mm, phase voltage 690V, rotor speed 600 min-1 rotor field coils with HTS-2G tapes. HTS-2G field coils located in the rotating cryostat and cooled by liquid nitrogen. The simulation and optimization of HTS-2G field coils geometry allowed to increase feed DC current up to 50A. Copper stator windings are water cooled. Magnetic and electrical losses in 1 MW HTS-2G generator do not exceed 1.6% of the nominal output power. In the construction of HTS-2G generator the wave multiplier with ratio 1:40 is used. The latter allows to reduce the total mass of HTS-2G generator down to 1.5 tons. The small-scale model of HTS-2G generator with output power 50 kW was designed, manufactured and tested. The test results showed good agreement with calculation results. The manufacturing of 1 MW HTS-2G generator is planned in 2014. This work is done under support of Rosatom within the frames of Russian Project "Superconducting Industry".

  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. Strong magnetic fields generated with a simple open-ended coil irradiated by high power laser pulses

    NASA Astrophysics Data System (ADS)

    Zhu, B. J.; Li, Y. T.; Yuan, D. W.; Li, Y. F.; Li, F.; Liao, G. Q.; Zhao, J. R.; Zhong, J. Y.; Xue, F. B.; He, S. K.; Wang, W. W.; Lu, F.; Zhang, F. Q.; Yang, L.; Zhou, K. N.; Xie, N.; Hong, W.; Wei, H. G.; Zhang, K.; Han, B.; Pei, X. X.; Liu, C.; Zhang, Z.; Wang, W. M.; Zhu, J. Q.; Gu, Y. Q.; Zhao, Z. Q.; Zhang, B. H.; Zhao, G.; Zhang, J.

    2015-12-01

    A simple scheme to produce strong magnetic fields due to cold electron flow in an open-ended coil heated by high power laser pulses is proposed. It differs from previous generation of magnetic fields driven by fast electron current in a capacitor-coil target [S. Fujioka et al., Sci. Rep. 3, 1170 (2013)]. The fields in our experiments are measured by B-dot detectors and proton radiography, respectively. A 205 T strong magnetic field at the center of the coil target is generated in the free space at Iλ2 of 6.85 × 1014 W cm-2 μm2, where I is the laser intensity, and λ is the laser wavelength. The magnetic field strength is proportional to Iλ2. Compared with the capacitor-coil target, the generation mechanism of the magnetic field is straightforward and the coil is easy to be fabricated.

  12. ELECTRODYNAMIC CONSTRAINTS ON HOMOGENEITY AND RF POWER DEPOSITION IN MULTIPLE COIL EXCITATIONS

    PubMed Central

    Lattanzi, Riccardo; Sodickson, Daniel K.; Grant, Aaron K.; Zhu, Yudong

    2009-01-01

    The promise of increased SNR and spatial/spectral resolution continues to drive MR technology toward higher magnetic field strengths. SAR management and B1 inhomogeneity correction become critical issues at the high frequencies associated with high field MR. In recent years, multiple coil excitation techniques have been recognized as potentially powerful tools for controlling SAR while simultaneously compensating for B1 inhomogeneities. This work explores electrodynamic constraints on transmit homogeneity and SAR, for both fully parallel transmission and its time-independent special case known as RF shimming. Ultimate intrinsic SAR – the lowest possible SAR consistent with electrodynamics for a particular excitation profile but independent of transmit coil design – is studied for different field strengths, object sizes and pulse acceleration factors. The approach to the ultimate intrinsic limit with increasing numbers of finite transmit coils is also studied, and the tradeoff between homogeneity and SAR is explored for various excitation strategies. In the case of fully parallel transmission, ultimate intrinsic SAR shows flattening or slight reduction with increasing field strength, in contradiction to the traditionally cited quadratic dependency, but consistent with established electrodynamic principles. PMID:19165885

  13. Accuracy of Prediction Method of Cryogenic Tensile Strength for Austenitic Stainless Steels in ITER Toroidal Field Coil Structure

    NASA Astrophysics Data System (ADS)

    Sakurai, Takeru; Icuchi, Masahide; Nakahira, Masatake; Saito, Toru; Morimoto, Masaaki; Inagaki, Takashi; Hong, Yunseok; Matsui, Kunihiro; Hemmi, Tsutomu; Kajitani, Hideki; Koizumi, Norikiyo

    The Japan Atomic Energy Agency (JAEA) has developed the prediction method for yield stress and ultimate tensile strength at liquid helium temperature (4 K) using the quadratic curve as a function of the content of carbon and nitrogen. Prediction method was formulated based on the tensile strength data of materials with shape of rectangle. In this study, tensile strength of the forged materials with round bar and complex shape were obtained so as to compare with the predicted value. The accuracy of the prediction method was 10.2% of Yield Strength (YS), 2.5% of Ultimate Tensile Strength (UTS) when the prediction method was applied to round bar forged materials. By contrast, the accuracy about prediction method was 1.8% of YS, -0.8% of UTS when prediction method was applied to complex shape forged materials. It can be presumed the tendency of tensile strength other than materials with shape of rectangle. However, it was found accuracy of round bar is larger than other materials because of difference in the forging method."The views and opinions expressed herein do not necessarily reflect those of the ITER Organization"

  14. Powering an Implantable Minipump with a Multi-layered Printed Circuit Coil for Drug Infusion Applications in Rodents

    PubMed Central

    Givrad, Tina K.; Maarek, Jean-Michel I.; Moore, William H.; Holschneider, Daniel P.

    2014-01-01

    We report the use of a multi-layer printed coil circuit for powering (36–94 mW) an implantable microbolus infusion pump (MIP) that can be activated remotely for use in drug infusion in nontethered, freely moving small animals. This implantable device provides a unique experimental tool with applications in the fields of animal behavior, pharmacology, physiology, and functional brain imaging. Two different designs are described: a battery-less pump usable when the animal is inside a home-cage surrounded by a primary inductive coil and a pump powered by a rechargeable battery that can be used for studies outside the homecage. The use of printed coils for powering of small devices by inductive power transfer presents significant advantages over similar approaches using hand-wound coils in terms of ease of manufacturing and uniformity of design. The high efficiency of a class-E oscillator allowed powering of the minipumps without the need for close physical contact of the primary and secondary coils, as is currently the case for most devices powered by inductive power transfer. PMID:20033778

  15. Online Classrooms: Powerful Tools for Rapid-Iteration Pedagogical Improvements

    NASA Astrophysics Data System (ADS)

    Horodyskyj, L.; Semken, S.; Anbar, A.; Buxner, S.

    2015-11-01

    Online education offers the opportunity to reach a variety of students including non-traditional and geographically diverse students. Research has shown that online courses modeled after traditional lecture-exam courses are ineffective. Over the past three years, Arizona State University developed and offered Habitable Worlds, an online-only astrobiology lab course featuring active learning tools. The course is offered in an intelligent tutoring system (ITS) that records a wealth of student data. In analyzing data from the Fall 2013 offering of the course, we were able to identify pre-post quiz results that were suboptimal and where in the lesson and how precisely students were missing concepts. The problem areas were redesigned, and the improved lessons were deployed a few months later. We saw significant improvements in our pre-post quiz results due to the implemented changes. This demonstrates the effectiveness of using robust ITS not only to present content online, but to provide instantaneous data for rapid iteration and improvement of existing content.

  16. CORRIGENDUM: Main safety issues at the transition from ITER to fusion power plants

    NASA Astrophysics Data System (ADS)

    Gulden, W.; Ciattaglia, S.; Massaut, V.; Sardain, P.

    2007-09-01

    In parallel to the ITER design process and in close cooperation with the designers a fusion-specific safety approach was developed and implemented. Detailed safety assessments have been performed and documented in the ITER Generic Site Safety Report (GSSR). Following the decision on ITER construction in France, results from the GSSR and from on-going safety-related activities tailored to the Cadarache site and the French licensing process are now being used to write the ITER Preliminary Safety Analysis Report. In the most recent European fusion power plant conceptual study (PPCS) inherent fusion favourable features have been exploited, by appropriate design and choice of materials, to provide major safety and environmental advantages. The study focused on five power plant models, which are illustrative of a wider spectrum of possibilities. These span a range from relatively near-term concepts, based on limited technology and plasma physics extrapolations, to a more advanced conception. All five PPCS plant models differ substantially in their plasma physics, blanket and divertor technology, size, fusion power and materials compositions, and these differences lead to differences in economic performance and in the details of safety and environmental impacts. This paper uses the quite detailed information available from ITER safety documents and highlights the differences between ITER and future fusion power plants. The main areas investigated are releases and doses during normal operation and under accidental conditions, occupational radiation exposure and optimization and waste management, including recycling and/or final disposal in repositories. Due to an error, an incorrect version of this paper was published in issue 7. For the convenience of the reader we have included the correct full article below rather than a list of changes.

  17. Design of a -1 MV dc UHV power supply for ITER NBI

    NASA Astrophysics Data System (ADS)

    Watanabe, K.; Yamamoto, M.; Takemoto, J.; Yamashita, Y.; Dairaku, M.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; Umeda, N.; Sakamoto, K.; Inoue, T.

    2009-05-01

    Procurement of a dc -1 MV power supply system for the ITER neutral beam injector (NBI) is shared by Japan and the EU. The Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes to the procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. The inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation has been carefully designed since dc long pulse insulation is quite different from conventional ac insulation or dc short pulse systems. A multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation the overall dimensions of the dc UHV components have been finalized. A surge energy suppression system is also essential to protect the accelerator from electric breakdowns. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J, which satisfies the design criteria of 50 J in total in the case of breakdown at -1 MV.

  18. Is the Standard Monte Carlo Power Iteration Approach the Wrong Approach? Part 2

    SciTech Connect

    Booth, Thomas E.

    2012-07-11

    The recent work 'Is the Standard Monte Carlo Power Iteration Approach the Wrong Approach?' speculated that the second eigenfunction could be built using essentially the same 'building brick' approach that obtained the first eigenfunction in LA-UR-12-21928. This note shows that the speculation was at least partially correct, but not complete.

  19. Quantitative Comparison of Minimum Inductance and Minimum Power Algorithms for the Design of Shim Coils for Small Animal Imaging.

    PubMed

    Hudson, Parisa; Hudson, Stephen D; Handler, William B; Scholl, Timothy J; Chronik, Blaine A

    2010-04-01

    High-performance shim coils are required for high-field magnetic resonance imaging and spectroscopy. Complete sets of high-power and high-performance shim coils were designed using two different methods: the minimum inductance and the minimum power target field methods. A quantitative comparison of shim performance in terms of merit of inductance (ML) and merit of resistance (MR) was made for shim coils designed using the minimum inductance and the minimum power design algorithms. In each design case, the difference in ML and the difference in MR given by the two design methods was <15%. Comparison of wire patterns obtained using the two design algorithms show that minimum inductance designs tend to feature oscillations within the current density; while minimum power designs tend to feature less rapidly varying current densities and lower power dissipation. Overall, the differences in coil performance obtained by the two methods are relatively small. For the specific case of shim systems customized for small animal imaging, the reduced power dissipation obtained when using the minimum power method is judged to be more significant than the improvements in switching speed obtained from the minimum inductance method.

  20. Conceptual design of contactless power transfer into HTS receiver coil using normal conducting resonance antenna

    NASA Astrophysics Data System (ADS)

    Kang, Hyoung Ku; Chung, Yoon Do; Yim, Seong Woo

    2014-09-01

    The contactless power transfer (CPT) technology based on strongly coupled electromagnetic resonators has been recently explored to realize the large power delivery and storage without any cable or wire across a large air gap. As the CPT technology makes possible the process of connector-free charging, it has been studied for practical applications to a variety of power applications. In the superconducting magnet system, a widespread method of electric energy supply is realized by the current lead which is one of indispensable subsystems in the power transfer equipment; however, it causes energy losses. To overcome such a problem, the combination CPT technology with HTS receiver coils has been proposed. It is called as, superconducting contactless power transfer (SUCPT) system. Such a technique has been expected a reasonable approach to provide a safe and convenient way of charging or storage without connecting joints in the superconducting applications. In this study, we presented the feasibility and various effects of transmission property from room temperature to very low temperature vessel within 40 cm under different material’s cooling vessels using radio frequency (RF) generator is 370 KHz.

  1. High-field actively detuneable transverse electromagnetic (TEM) coil with low-bias voltage for high-power RF transmission.

    PubMed

    Avdievich, Nikolai I; Bradshaw, Ken; Kuznetsov, Andrey M; Hetherington, Hoby P

    2007-06-01

    The design and construction of a 4T (170 MHz) transverse electromagnetic (TEM) actively detuneable quadrature head coil is described. Conventional schemes for active detuning require high negative bias voltages (>300 V) to prevent leakage of RF pulses with amplitudes of 1-2 kW. To extend the power handling capacity and avoid the use of high DC bias voltages, we developed an alternate method of detuning the volume coil. In this method the PIN diodes in the detuning circuits are shorted when the RF volume coil is tuned, and negatively biased with -12 V when the coil is detuned. To preserve the high Q(U)/Q(L) ratio of the TEM coil, we modified the method of Nabetani and Watkins (Proceedings of the 13th Annual Meeting of ISMRM, Kyoto, Japan, 2004, abstract 1574) by utilizing a high-impedance (approximately 200 Omega), lumped-element, quarter-wavelength transformer. A Q(U) of 500 was achieved for the detuneable TEM, such that incorporation of the detuning network had minimal effect (<1 dB) on the performance of the coil in vivo. PMID:17534919

  2. Initial results for a 170 GHz high power ITER waveguide component test stand

    NASA Astrophysics Data System (ADS)

    Bigelow, Timothy; Barker, Alan; Dukes, Carl; Killough, Stephen; Kaufman, Michael; White, John; Bell, Gary; Hanson, Greg; Rasmussen, Dave

    2014-10-01

    A high power microwave test stand is being setup at ORNL to enable prototype testing of 170 GHz cw waveguide components being developed for the ITER ECH system. The ITER ECH system will utilize 63.5 mm diameter evacuated corrugated waveguide and will have 24 >150 m long runs. A 170 GHz 1 MW class gyrotron is being developed by Communications and Power Industries and is nearing completion. A HVDC power supply, water-cooling and control system has been partially tested in preparation for arrival of the gyrotron. The power supply and water-cooling system are being designed to operate for >3600 second pulses to simulate the operating conditions planned for the ITER ECH system. The gyrotron Gaussian beam output has a single mirror for focusing into a 63.5 mm corrugated waveguide in the vertical plane. The output beam and mirror are enclosed in an evacuated duct with absorber for stray radiation. Beam alignment with the waveguide is a critical task so a combination of mirror tilt adjustments and a bellows for offsets will be provided. Analysis of thermal patterns on thin witness plates will provide gyrotron mode purity and waveguide coupling efficiency data. Pre-prototype waveguide components and two dummy loads are available for initial operational testing of the gyrotron. ORNL is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under Contract DE-AC-05-00OR22725.

  3. Biologically relevant molecular transducer with increased computing power and iterative abilities.

    PubMed

    Ratner, Tamar; Piran, Ron; Jonoska, Natasha; Keinan, Ehud

    2013-05-23

    As computing devices, which process data and interconvert information, transducers can encode new information and use their output for subsequent computing, offering high computational power that may be equivalent to a universal Turing machine. We report on an experimental DNA-based molecular transducer that computes iteratively and produces biologically relevant outputs. As a proof of concept, the transducer accomplished division of numbers by 3. The iterative power was demonstrated by a recursive application on an obtained output. This device reads plasmids as input and processes the information according to a predetermined algorithm, which is represented by molecular software. The device writes new information on the plasmid using hardware that comprises DNA-manipulating enzymes. The computation produces dual output: a quotient, represented by newly encoded DNA, and a remainder, represented by E. coli phenotypes. This device algorithmically manipulates genetic codes. PMID:23706637

  4. High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system

    NASA Astrophysics Data System (ADS)

    Takahashi, K.; Kajiwara, K.; Oda, Y.; Kasugai, A.; Kobayashi, N.; Sakamoto, K.; Doane, J.; Olstad, R.; Henderson, M.

    2011-06-01

    High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

  5. High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system.

    PubMed

    Takahashi, K; Kajiwara, K; Oda, Y; Kasugai, A; Kobayashi, N; Sakamoto, K; Doane, J; Olstad, R; Henderson, M

    2011-06-01

    High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

  6. High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system

    SciTech Connect

    Takahashi, K.; Kajiwara, K.; Oda, Y.; Kasugai, A.; Kobayashi, N.; Sakamoto, K.; Doane, J.; Olstad, R.; Henderson, M.

    2011-06-15

    High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20 deg. - 40 deg. from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

  7. Stray RF Power Estimates From EC Exploitation During ITER Plasma Operations

    SciTech Connect

    Gandini, F.; Henderson, M.; Darbos, C.; Gassmann, T.; Purohit, D.; Omori, T.; Nazare, C.

    2011-12-23

    The EC H and CD system of ITER tokamak is an essential tool for all the phases of ITER operation. Different levels of EC power are required through all the plasma discharge: up to 6.7 MW for assisting the breakdown and burn through, up to 20 MW for current drive and saw-teeth control from the equatorial launcher and up to 20 MW for NTM stabilization from the upper launchers. The assistance to breakdown and burn through is characterized by a very low (if not negligible) RF power absorption by the plasma. A significant level of stray radiation may also arise from partial absorption due to non-optimal plasma parameters and/or wrong injected polarization. The stray power radiated in the vacuum chamber is estimated as a first step toward mitigating potential harmful consequence to in-vessel structures and diagnostics. Power loading of the chamber walls (peek power and average power density for straight beam propagation in the empty chamber) and diffuse stray radiation effects are simulated to infer suitable strategies to avoid damage to first wall and to microwave sensitive components.

  8. Is the Standard Monte Carlo Power Iteration Approach the Wrong Approach?

    SciTech Connect

    Booth, Thomas E

    2012-06-05

    The power iteration method is the standard Monte Carlo approach for obtaining the eigenfunctions of a nuclear system, but the power method sometimes converges very slowly. Most discussions give a mathematical reason for the slow convergence of the Monte Carlo power method using the same concepts and terminology as when the power method is applied to a deterministic problem. This note first looks at why the convergence is slow from an intuitive Monte Carlo neutron perspective. Second, this note proposes building an eigenfunction intuitively in a cumulative (and noniterative) neutron by neutron manner that tends to better direct neutrons to where the neutrons need to be. Third, a very similar method for building the second eigenfunction is speculatively proposed.

  9. Analysis of Iterative Waterfilling Algorithm for Multiuser Power Control in Digital Subscriber Lines

    NASA Astrophysics Data System (ADS)

    Luo, Zhi-Quan; Pang, Jong-Shi

    2006-12-01

    We present an equivalent linear complementarity problem (LCP) formulation of the noncooperative Nash game resulting from the DSL power control problem. Based on this LCP reformulation, we establish the linear convergence of the popular distributed iterative waterfilling algorithm (IWFA) for arbitrary symmetric interference environment and for certain asymmetric channel conditions with any number of users. In the case of symmetric interference crosstalk coefficients, we show that the users of IWFA in fact, unknowingly but willingly, cooperate to minimize a common quadratic cost function whose gradient measures the received signal power from all users. This is surprising since the DSL users in the IWFA have no intention to cooperate as each maximizes its own rate to reach a Nash equilibrium. In the case of asymmetric coefficients, the convergence of the IWFA is due to a contraction property of the iterates. In addition, the LCP reformulation enables us to solve the DSL power control problem under no restrictions on the interference coefficients using existing LCP algorithms, for example, Lemke's method. Indeed, we use the latter method to benchmark the empirical performance of IWFA in the presence of strong crosstalk interference.

  10. 3D edge transport analysis of ITER start-up configuration for limiter power load assessment

    NASA Astrophysics Data System (ADS)

    Kobayashi, M.; Feng, Y.; Loarte, A.; Federici, G.; Strohmayer, G.; Shimada, M.; Sardei, F.; Reiter, D.; Sugihara, M.

    2007-02-01

    The edge transport properties of the toroidally discrete limiter configuration in the ITER start-up phase has been analysed, using the 3D edge transport code, EMC3-EIRENE. Because of the finite magnetic shear in the edge, the interaction of the limiters with flux surfaces of different q-values introduces a complex 3D pattern in the connection length (LC) profiles, where long and short flux tubes co-exist in the scrape-off layer. The severity of problems associated with very long flux tubes in the edge, which could bring a large amount of energy (proportional to the square root of LC) and cause a hot spot on the limiter, was mitigated and no significant localized power load was found. This can be justified as follows. (i) For long flux tubes, the perpendicular energy transport time becomes shorter than the parallel energy transport time, resulting in no net energy input to the flux tube. (ii) Perpendicular transport was found to be very effective to smear out the difference in the parallel energy flux conducted by the various flux tubes, if they interact within a perpendicular transport scale, about a few cm, which is usually the case in high plasma current ITER start-up configuration. These two effects significantly reduce the dependence of energy deposition on LC. At the high plasma current (e.g. 6.5 MA), the peak power load is found to be close to the engineering limit, especially for lowest perpendicular transport coefficients and the highest input power. Comparing the results of the 3D modelling with a radial exponential decay model, it was found that by neglecting the 3D geometrical effects, the simple model overestimates the peak power load by ~30% for corresponding input power and radial decay of energy flux.

  11. Simulation of High Power ICRF Wave Heating in the ITER Burning Plasma

    NASA Astrophysics Data System (ADS)

    Jaeger, E. F.; Berry, L. A.; Barrett, R. F.; D'Azevedo, E. F.

    2007-11-01

    ITER relies on Ion-cyclotron Radio Frequency (ICRF) power to heat the plasma to fusion temperatures. To heat effectively, the waves must couple efficiently to the core plasma. Recent simulations using AORSA [1] on the 120 TF Cray XT-4 (Jaguar) at ORNL show that the waves propagate radially inward and are rapidly absorbed with little heating of the plasma edge. AORSA has achieved 87.5 trillion calculations per second (87.5 teraflops) on Jaguar, which is 73 percent of the system's theoretical peak. Three dimensional visualizations show ``hot spots'' near the antenna surface where the wave amplitude is high. AORSA simulations are also being used to study how to best use ICRF to drive plasma currents for optimizing ITER performance and pulse length. Results for Scenario 4 show a maximum current of 0.54 MA for 20 MW of power at 57 MHz. [1] E.F. Jaeger, L.A. Berry, E. D'Azevedo, et al., Phys. Plasmas. 8, 1573 (2001).

  12. On the Sequential Control of ITER Poloidal Field Converters for Reactive Power Reduction

    NASA Astrophysics Data System (ADS)

    Yuan, Hongwen; Fu, Peng; Gao, Ge; Huang, Liansheng; Song, Zhiquan; He, Shiying; Wu, Yanan; Dong, Lin; Wang, Min; Fang, Tongzhen

    2014-12-01

    Sequential control applied to the International Thermonuclear Experimental Reactor (ITER) poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbar is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.

  13. Calibration of fiber-optic shock pyrometer using high-power coiled tungsten lamp

    NASA Astrophysics Data System (ADS)

    Fat'yanov, O. V.; Asimow, P. D.

    2015-06-01

    Comparison of all known calibration sources indicates that coiled standards of spectral irradiance, despite their very non-uniform brightness, are currently the best practical choice for accurate shock temperature measurements above 3000 K by optical pyrometry. We review all three documented methods of shock pyrometer calibration to a coiled lamp and show that only one technique, with no fiber-optics employed, is free of major radiometric errors. We report the development of a new, accurate to 5% and precise to 1-1.5% calibration procedure for the modified Caltech 6-channel, 3-ns temporal resolution combined open beam and fiber-coupled instrument. A designated central area of an 0.7x demagnified image of 900 W coiled-coil lamp filament is used, cross-calibrated against a NIST-traceable tungsten ribbon lamp. The results of two slightly different cross-calibrations are reported and the procedure to characterize the difference between the static and dynamic response of NewFocus 1801 amplified photodetectors. The most essential requirements for error-free calibration of a fiber-optic pyrometer using a coiled irradiance standard lamp are discussed. All these conditions are validated in actual radiometric tests and shock temperature experiments on single-crystal NaCl and MgO.

  14. Investigation of the B1 field distribution and RF power deposition in a birdcage coil as functions of the number of coil legs at 4.7 T, 7.0 T, and 11.7 T

    NASA Astrophysics Data System (ADS)

    Seo, Jeung-Hoon; Han, Sang-Doc; Kim, Kyoung-Nam

    2015-06-01

    The proper design of birdcage (BC) coils plays a very important role in the acquisition of highresolution magnetic resonance imaging (MRI) of small animals such as rodents. In this context, we investigate multiple-leg (8-, 16-, 32-, 64-, and 128-leg) BC coils operating at ultra-high fields (UHF) of 7.0 T and 11.7 T and a high-field (HF) of 4.7 T for rodent magnetic resonance imaging (MRI). Primarily, Our study comparatively examines the parameters of the radiofrequency (RF) transmission (|B1 +|)-field, the magnetic flux (|B1|)-field, and RF power deposition (RF-PD) as functions of the number of BC-coil legs via finite-difference time-domain (FDTD) calculations under realistic loading conditions with a biological phantom. In particular, the specific ratio |E/B1 +| is defined for predicting RF-PD values in different coil structures. Our results indicate that the optimal number of legs of the BC coil can be chosen for different resonance frequencies of 200 MHz, 300 MHz, and 500 MHz and that this choice can be lead to superior |B1 +|-field intensity and |B1|-field homogeneity and decreased RF-PD. We believe that our approach to determining the optimal number of legs for a BC coil can contribute to rodent MR imaging.

  15. A fresh look at electron cyclotron current drive power requirements for stabilization of tearing modes in ITER

    SciTech Connect

    La Haye, R. J.

    2015-12-10

    ITER is an international project to design and build an experimental fusion reactor based on the “tokamak” concept. ITER relies upon localized electron cyclotron current drive (ECCD) at the rational safety factor q=2 to suppress or stabilize the expected poloidal mode m=2, toroidal mode n=1 neoclassical tearing mode (NTM) islands. Such islands if unmitigated degrade energy confinement, lock to the resistive wall (stop rotating), cause loss of “H-mode” and induce disruption. The International Tokamak Physics Activity (ITPA) on MHD, Disruptions and Magnetic Control joint experiment group MDC-8 on Current Drive Prevention/Stabilization of Neoclassical Tearing Modes started in 2005, after which assessments were made for the requirements for ECCD needed in ITER, particularly that of rf power and alignment on q=2 [1]. Narrow well-aligned rf current parallel to and of order of one percent of the total plasma current is needed to replace the “missing” current in the island O-points and heal or preempt (avoid destabilization by applying ECCD on q=2 in absence of the mode) the island [2-4]. This paper updates the advances in ECCD stabilization on NTMs learned in DIII-D experiments and modeling during the last 5 to 10 years as applies to stabilization by localized ECCD of tearing modes in ITER. This includes the ECCD (inside the q=1 radius) stabilization of the NTM “seeding” instability known as sawteeth (m/n=1/1) [5]. Recent measurements in DIII-D show that the ITER-similar current profile is classically unstable, curvature stabilization must not be neglected, and the small island width stabilization effect from helical ion polarization currents is stronger than was previously thought [6]. The consequences of updated assumptions in ITER modeling of the minimum well-aligned ECCD power needed are all-in-all favorable (and well-within the ITER 24 gyrotron capability) when all effects are included. However, a “wild card” may be broadening of the localized

  16. A fresh look at electron cyclotron current drive power requirements for stabilization of tearing modes in ITER

    NASA Astrophysics Data System (ADS)

    La Haye, R. J.

    2015-12-01

    ITER is an international project to design and build an experimental fusion reactor based on the "tokamak" concept. ITER relies upon localized electron cyclotron current drive (ECCD) at the rational safety factor q=2 to suppress or stabilize the expected poloidal mode m=2, toroidal mode n=1 neoclassical tearing mode (NTM) islands. Such islands if unmitigated degrade energy confinement, lock to the resistive wall (stop rotating), cause loss of "H-mode" and induce disruption. The International Tokamak Physics Activity (ITPA) on MHD, Disruptions and Magnetic Control joint experiment group MDC-8 on Current Drive Prevention/Stabilization of Neoclassical Tearing Modes started in 2005, after which assessments were made for the requirements for ECCD needed in ITER, particularly that of rf power and alignment on q=2 [1]. Narrow well-aligned rf current parallel to and of order of one percent of the total plasma current is needed to replace the "missing" current in the island O-points and heal or preempt (avoid destabilization by applying ECCD on q=2 in absence of the mode) the island [2-4]. This paper updates the advances in ECCD stabilization on NTMs learned in DIII-D experiments and modeling during the last 5 to 10 years as applies to stabilization by localized ECCD of tearing modes in ITER. This includes the ECCD (inside the q=1 radius) stabilization of the NTM "seeding" instability known as sawteeth (m/n=1/1) [5]. Recent measurements in DIII-D show that the ITER-similar current profile is classically unstable, curvature stabilization must not be neglected, and the small island width stabilization effect from helical ion polarization currents is stronger than was previously thought [6]. The consequences of updated assumptions in ITER modeling of the minimum well-aligned ECCD power needed are all-in-all favorable (and well-within the ITER 24 gyrotron capability) when all effects are included. However, a "wild card" may be broadening of the localized ECCD by the presence of

  17. Adaptive switching detection algorithm for iterative-MIMO systems to enable power savings

    NASA Astrophysics Data System (ADS)

    Tadza, N.; Laurenson, D.; Thompson, J. S.

    2014-11-01

    This paper attempts to tackle one of the challenges faced in soft input soft output Multiple Input Multiple Output (MIMO) detection systems, which is to achieve optimal error rate performance with minimal power consumption. This is realized by proposing a new algorithm design that comprises multiple thresholds within the detector that, in real time, specify the receiver behavior according to the current channel in both slow and fast fading conditions, giving it adaptivity. This adaptivity enables energy savings within the system since the receiver chooses whether to accept or to reject the transmission, according to the success rate of detecting thresholds. The thresholds are calculated using the mutual information of the instantaneous channel conditions between the transmitting and receiving antennas of iterative-MIMO systems. In addition, the power saving technique, Dynamic Voltage and Frequency Scaling, helps to reduce the circuit power demands of the adaptive algorithm. This adaptivity has the potential to save up to 30% of the total energy when it is implemented on Xilinx®Virtex-5 simulation hardware. Results indicate the benefits of having this "intelligence" in the adaptive algorithm due to the promising performance-complexity tradeoff parameters in both software and hardware codesign simulation.

  18. Antenna and coil design for wireless signal detection and charging of embedded power active contact lens.

    PubMed

    Ng, Benny; Heckler, Paul; Do, Alex; Azar, Phillip; Leon, Errol; Smilkstein, Tina

    2014-01-01

    This paper presents a screen printed 2.4 GHz antenna and induction charging coil for an active contact lens with a single large pixel user display and on-board 3.8 V 5 uAh rechargeable battery. The antenna traces are printed using silver conductive paste on a 25 um polyethylene terephthalate (PET) substrate. The incoming signal from the antenna feeds into an IC that amplifies and rectifies the signal. The coil provides wireless energy transfer to inductively charge a thin film battery [1] located on the contact lens. The printed antenna achieved a S11 of -4 dB at 2.4 GHz and a gain of -13 dB. PMID:25571353

  19. Study of the effect of distance and misalignment between magnetically coupled coils for wireless power transfer in intraocular pressure measurement.

    PubMed

    Rendon-Nava, Adrian E; Díaz-Méndez, J Alejandro; Nino-de-Rivera, Luis; Calleja-Arriaga, Wilfrido; Gil-Carrasco, Felix; Díaz-Alonso, Daniela

    2014-01-01

    An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them. PMID:25097887

  20. Study of the Effect of Distance and Misalignment between Magnetically Coupled Coils for Wireless Power Transfer in Intraocular Pressure Measurement

    PubMed Central

    Rendon-Nava, Adrian E.; Díaz-Méndez, J. Alejandro; Nino-de-Rivera, Luis; Calleja-Arriaga, Wilfrido; Gil-Carrasco, Felix; Díaz-Alonso, Daniela

    2014-01-01

    An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them. PMID:25097887

  1. Coiled tubing drilling: Real time MWD with dedicated powers to the BHA

    SciTech Connect

    Leismer, D.; Williams, B.; Pursell, J.

    1996-12-31

    This paper describes and analyzes the development and ongoing field trials of a Real Time MWD Coiled Tubing Drilling System. The new system holds great promise for advancing the state of coiled tubing drilling for certain applications. The system is designed for through-tubing, short radius re-entry and drilling highly deviated wells as horizontal laterals to a geologic target with minimum wellbore tortuosity. Currently, 4-1/2-in production tubing is the smallest re-entry candidate. Real time MWD and Bottom Hole Assembly (BHA) control is achieved by the use of a combination hydraulic and electric umbilical internal to the coiled tubing (CT), allowing continuous data collection and selective surface control of the BHA components. This communication line allows orientation in 10{degree} increments (or less) while drilling, applies weight-on-bit and operates a reusable circulating valve. In addition, the umbilical provides real-time monitoring of weight-on-bit, circulating pressures of the drilling fluid internal and external to the BHA, dedicated hydraulic system bottom hole pressure, downhole temperature and survey data from logging equipment.

  2. Wireless powering electronics and spiral coils for implant microsystem toward nanomedicine diagnosis and therapy in free-behavior animal

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Wei; Hou, Kuan-Chou; Shieh, Li-Jung; Hung, Sheng-Hsin; Chiou, Jin-Chern

    2012-11-01

    In this paper, we present a wireless RF-powering electronics system approach for batteryless implantable biomedical microsystem with versatile sensors/actuators on laboratory animals toward diagnosis and therapy applications. Miniaturized spiral coils as a wireless power module with low-dropout (LDO) linear regulator circuit convert RF signal into DC voltage, provide a batteryless implantation for truly free-behavior monitoring without wire dragging. Presented design achieves low quiescent-current and Line/Load Regulation, high antenna/current efficiency with safety considerations including temperature and electromagnetic absorption issues to avoid damage to the implanted target volume of tissue. Related system performance measurements have been successfully completed to demonstrate the wireless powering capabilities in desired implantable microsystems.

  3. Control of a pneumatic power active lower-limb orthosis with filter-based iterative learning control

    NASA Astrophysics Data System (ADS)

    Huang, Chia-En; Chen, Jian-Shiang

    2014-05-01

    A filter-based iterative learning control (FILC) scheme is developed in this paper, which consists in a proportional-derivative (PD) feedback controller and a feedforward filter. Moreover, based on two-dimensional system theory, the stability of the FILC system is proven. The design criteria for a wavelet transform filter (WTF) - chosen as the feedforward filter - and the PD feedback controller are also given. Finally, using a pneumatic power active lower-limb orthosis (PPALO) as the controlled plant, the wavelet-based iterative learning control (WILC) implementation and the orchestration of a trajectory tracking control simulation are given in detail and the overall tracking performance is validated.

  4. Commercial applications for COIL

    NASA Astrophysics Data System (ADS)

    Solomon, Wayne C.; Carroll, David L.; King, D. M.; Fockler, L. A.; Stromberg, D. S.; Sexauer, M.; Milmoe, A.; Sentman, Lee H.

    2000-01-01

    The chemical oxygen-iodine laser (COIL) is a high power, fiber deliverable tool, which can be used for a number of different industrial applications. COIL is of particular interest because of its short fiber deliverable wavelength, high scaleable continuous wave power, and excellent material interaction properties. In past research the University of Illinois at Urbana-Champaign identified and decommissioning and decontamination (DD) of nuclear facilities as a primary focus for COIL technology. DD will be a major challenge in the coming decades. The use of a robotically driven fiber delivered cutting/ablation tool in contaminated areas promises to lower risks to workers for the DD mission. Further, the high cutting speed of COIL will significantly reduce the time required to cut contaminated equipment, reducing costs. The high power of COIL will permit the dismantling of thick stacks of piping and equipment as well as reactor vessels. COIL is very promising for the removal of material from contaminated surfaces, perhaps to depths thicker than an inch. Laser cutting and ablation minimizes dust and fumes, which reduces the required number of high efficiency particulate accumulator filters, thus reducing costly waste disposal. Other potential industrial applications for COIL are shipbuilding, automotive manufacturing, heavy machinery manufacturing, tasks requiring underwater cutting or welding, and there appear to be very promising applications for high powers lasers in the oil industry.

  5. α/β coiled coils.

    PubMed

    Hartmann, Marcus D; Mendler, Claudia T; Bassler, Jens; Karamichali, Ioanna; Ridderbusch, Oswin; Lupas, Andrei N; Hernandez Alvarez, Birte

    2016-01-15

    Coiled coils are the best-understood protein fold, as their backbone structure can uniquely be described by parametric equations. This level of understanding has allowed their manipulation in unprecedented detail. They do not seem a likely source of surprises, yet we describe here the unexpected formation of a new type of fiber by the simple insertion of two or six residues into the underlying heptad repeat of a parallel, trimeric coiled coil. These insertions strain the supercoil to the breaking point, causing the local formation of short β-strands, which move the path of the chain by 120° around the trimer axis. The result is an α/β coiled coil, which retains only one backbone hydrogen bond per repeat unit from the parent coiled coil. Our results show that a substantially novel backbone structure is possible within the allowed regions of the Ramachandran space with only minor mutations to a known fold.

  6. Conceptual design of MgB2 coil for the 100 MJ SMES of advanced superconducting power conditioning system (ASPCS)

    NASA Astrophysics Data System (ADS)

    Atomura, Naoki; Takahashi, Toshinori; Amata, Hiroto; Iwasaki, Tatsuya; Son, Kyoungwoo; Miyagi, Daisuke; Tsuda, Makoto; Hamajima, Takataro; Shintomi, Takakazu; Makida, Yasuhiro; Takao, Tomoaki; Munakata, Kohe; Kajiwara, Masataka

    In order to reduce global carbon-dioxide in the world, we propose an Advanced Superconducting Power Conditioning System (ASPCS) which is composed of 5 MW renewable energy resources and 1 MW hybrid storage system. The hybrid storage system is composed of FC-H2-EL and SMES which is installed adjacent to a LH2 station for vehicles. Since the SMES can be operated at 20 K which is a saturated temperature of LH2, we can use MgB2 superconductors. In the ASPCS, 100 MJ storage capacities of the SMES should be required. This paper focuses on studies into a conceptual design of SMES toroidal coil composed of the MgB2 and indirectly cooled by LH2.

  7. Demonstration of the ITER Power Exhaust Solution Using the Puff and Pump Technique on DIII-D

    SciTech Connect

    Wade, M.R.; West, W.P.; Hill, D.N.; Allen, S.L.; Boedo, J.A.; Brooks, N.H.; Fenstermacher, M.E.; Hogan, J.T.; Isler, R.C.; Jayakumar, R.J.; Lasnier, C.J.; Lehmer, R.; Leonard, A.W.; Maingi, R.; Moyer, R.A.; Petrie, T.W.; Schaffer, M.J.; Watkins, J.G.; Whyte, D.G.; Wood, R.D.

    1999-07-01

    In future, high power density fusion devices, the need to prevent excessive local deposition of the plasma energy efflux on the first-wall surfaces is a critical design consideration in order to maintain the integrity of such surfaces. This requirement must be met without significant impact on plasma purity or overall plasma confinement. For the International Thermonuclear Experimental Reactor (ITER), these constraints have led to the following design criteria [1] P{sub rad}/(P{sub input} + P{sub {alpha}}) = 83%, P{sub rad,core}/(P{sub input} + P{sub {alpha}}) = 33%, P{sub target}/P{sub loss} = 17%, Z{sub eff} < 1.8, and {tau}{sub E}/{tau}{sub E,ITER93H} > 0.85. Here, P{sub loss} is the power flowing out of the core (i.e., P{sub input} + P{sub {alpha}} - P{sub rad,core})and P{sub target} is the power conducted to the target plate. These criteria represent a compromise between obtaining sufficient radiation to reduce the target heat load to a tolerable level, minimizing core fuel dilution, and maintaining sufficient power flow through the edge plasma to maintain H-mode confinement. Past experiments have had difficulty achieving these conditions simultaneously when using seeded impurities, and therefore there has been some concern regarding the viability of the ITER design. However, recent experiments in DIII-D using the puff and pump technique with argon as the seeded impurity have demonstrated the compatibility of these design constraints. In particular, steady-state plasma conditions have been achieved with P{sub rad}/P{sub input} = 72%, P{sub rad,core}/P{sub input} = 16%, P{sub target}/P{sub loss} = 17%, Z{sub eff} = 1.85, and {tau}{sub E}/{tau}{sub E,ITER93H} = 1.05.

  8. A Validation of the Spectral Power Clustering Technique (SPCT) by Using a Rogowski Coil in Partial Discharge Measurements

    PubMed Central

    Ardila-Rey, Jorge Alfredo; Albarracín, Ricardo; Álvarez, Fernando; Barrueto, Aldo

    2015-01-01

    Both in industrial as in controlled environments, such as high-voltage laboratories, pulses from multiple sources, including partial discharges (PD) and electrical noise can be superimposed. These circumstances can modify and alter the results of PD measurements and, what is more, they can lead to misinterpretation. The spectral power clustering technique (SPCT) allows separating PD sources and electrical noise through the two-dimensional representation (power ratio map or PR map) of the relative spectral power in two intervals, high and low frequency, calculated for each pulse captured with broadband sensors. This method allows to clearly distinguishing each of the effects of noise and PD, making it easy discrimination of all sources. In this paper, the separation ability of the SPCT clustering technique when using a Rogowski coil for PD measurements is evaluated. Different parameters were studied in order to establish which of them could help for improving the manual selection of the separation intervals, thus enabling a better separation of clusters. The signal processing can be performed during the measurements or in a further analysis. PMID:26473872

  9. A validation of the spectral power clustering technique (SPCT) by using a Rogowski coil in partial discharge measurements.

    PubMed

    Ardila-Rey, Jorge Alfredo; Albarracín, Ricardo; Álvarez, Fernando; Barrueto, Aldo

    2015-01-01

    Both in industrial as in controlled environments, such as high-voltage laboratories, pulses from multiple sources, including partial discharges (PD) and electrical noise can be superimposed. These circumstances can modify and alter the results of PD measurements and, what is more, they can lead to misinterpretation. The spectral power clustering technique (SPCT) allows separating PD sources and electrical noise through the two-dimensional representation (power ratio map or PR map) of the relative spectral power in two intervals, high and low frequency, calculated for each pulse captured with broadband sensors. This method allows to clearly distinguishing each of the effects of noise and PD, making it easy discrimination of all sources. In this paper, the separation ability of the SPCT clustering technique when using a Rogowski coil for PD measurements is evaluated. Different parameters were studied in order to establish which of them could help for improving the manual selection of the separation intervals, thus enabling a better separation of clusters. The signal processing can be performed during the measurements or in a further analysis. PMID:26473872

  10. Long pulse acceleration of MeV class high power density negative H{sup −} ion beam for ITER

    SciTech Connect

    Umeda, N. Kojima, A.; Kashiwagi, M.; Tobari, H.; Hiratsuka, J.; Watanabe, K.; Dairaku, M.; Yamanaka, H.; Hanada, M.

    2015-04-08

    R and D of high power density negative ion beam acceleration has been carried out at MeV test facility in JAEA to realize ITER neutral beam accelerator. The main target is H{sup −} ion beam acceleration up to 1 MeV with 200 A/m{sup 2} for 60 s whose pulse length is the present facility limit. For long pulse acceleration at high power density, new extraction grid (EXG) has been developed with high cooling capability, which electron suppression magnet is placed under cooling channel similar to ITER. In addition, aperture size of electron suppression grid (ESG) is enlarged from 14 mm to 16 mm to reduce direct interception on the ESG and emission of secondary electron which leads to high heat load on the upstream acceleration grid. By enlarging ESG aperture, beam current increased 10 % at high current beam and total acceleration grid heat load reduced from 13 % to 10 % of input power at long pulse beam. In addition, heat load by back stream positive ion into the EXG is measured for the first time and is estimated as 0.3 % of beam power, while heat load by back stream ion into the source chamber is estimated as 3.5 ~ 4.0 % of beam power. Beam acceleration up to 60 s which is the facility limit, has achieved at 683 keV, 100 A/m{sup 2} of negative ion beam, whose energy density increases two orders of magnitude since 2011.

  11. Low pressure and high power rf sources for negative hydrogen ions for fusion applications (ITER neutral beam injection).

    PubMed

    Fantz, U; Franzen, P; Kraus, W; Falter, H D; Berger, M; Christ-Koch, S; Fröschle, M; Gutser, R; Heinemann, B; Martens, C; McNeely, P; Riedl, R; Speth, E; Wünderlich, D

    2008-02-01

    The international fusion experiment ITER requires for the plasma heating and current drive a neutral beam injection system based on negative hydrogen ion sources at 0.3 Pa. The ion source must deliver a current of 40 A D(-) for up to 1 h with an accelerated current density of 200 Am/(2) and a ratio of coextracted electrons to ions below 1. The extraction area is 0.2 m(2) from an aperture array with an envelope of 1.5 x 0.6 m(2). A high power rf-driven negative ion source has been successfully developed at the Max-Planck Institute for Plasma Physics (IPP) at three test facilities in parallel. Current densities of 330 and 230 Am/(2) have been achieved for hydrogen and deuterium, respectively, at a pressure of 0.3 Pa and an electron/ion ratio below 1 for a small extraction area (0.007 m(2)) and short pulses (<4 s). In the long pulse experiment, equipped with an extraction area of 0.02 m(2), the pulse length has been extended to 3600 s. A large rf source, with the width and half the height of the ITER source but without extraction system, is intended to demonstrate the size scaling and plasma homogeneity of rf ion sources. The source operates routinely now. First results on plasma homogeneity obtained from optical emission spectroscopy and Langmuir probes are very promising. Based on the success of the IPP development program, the high power rf-driven negative ion source has been chosen recently for the ITER beam systems in the ITER design review process.

  12. Borehole induction coil transmitter

    SciTech Connect

    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.

  13. α/β coiled coils

    PubMed Central

    Hartmann, Marcus D; Mendler, Claudia T; Bassler, Jens; Karamichali, Ioanna; Ridderbusch, Oswin; Lupas, Andrei N; Hernandez Alvarez, Birte

    2016-01-01

    Coiled coils are the best-understood protein fold, as their backbone structure can uniquely be described by parametric equations. This level of understanding has allowed their manipulation in unprecedented detail. They do not seem a likely source of surprises, yet we describe here the unexpected formation of a new type of fiber by the simple insertion of two or six residues into the underlying heptad repeat of a parallel, trimeric coiled coil. These insertions strain the supercoil to the breaking point, causing the local formation of short β-strands, which move the path of the chain by 120° around the trimer axis. The result is an α/β coiled coil, which retains only one backbone hydrogen bond per repeat unit from the parent coiled coil. Our results show that a substantially novel backbone structure is possible within the allowed regions of the Ramachandran space with only minor mutations to a known fold. DOI: http://dx.doi.org/10.7554/eLife.11861.001 PMID:26771248

  14. High power plasma interaction with tungsten grades in ITER relevant conditions

    NASA Astrophysics Data System (ADS)

    Garkusha, I. E.; Makhlaj, V. A.; Aksenov, N. N.; Byrka, O. V.; Malykhin, S. V.; Pugachov, A. T.; Bazylev, B.; Landman, I.; Pinsuk, G.; Linke, J.; Wirtz, M.; Sadowski, M. J.; Skladnik-Sadowska, E.

    2015-03-01

    Experimental simulations of ITER-like transient events with relevant surface heat load parameters (energy density up to 1.1 MJ/m2 and the pulse duration of 0.25 ms) as well as particle loads (varied in wide range from 1023 to 1027 ion/m2 s) were carried out with a quasistationary plasma accelerator QSPA Kh-50. Particular attention was paid to elaboration of damage of tungsten as a main candidate material for ITER divertor surfaces and also as prospective material for DEMO design. Erosion features, cracks evolution and changes in their thickness with increasing exposition dose are studied for different W grades, including deformed material with elongated grains, as well as WTa5 and sintered tungsten.

  15. Analysis of power deposition and temperature rise due to presence of an implant inside a 1.5 t MRI RF coil.

    PubMed

    Kozlov, M; Schaefers, G

    2015-08-01

    We numerically investigated power deposition and temperature rise generated due to the presence of a titanium rod placed in a phantom, located inside a 1.5 T coil. The induced power deposition and temperature rise normalized to incident tangential electric field was found to be dependent on distance to the phantom wall. The different dependence of the integral of power deposition over a box surrounded the rod and the temperature rise on American Society for Testing and Materials (ASTM) phantom medium electrical conductivity was observed. The consequences of numerical domain simplification have been analyzed. PMID:26737609

  16. Lanczos iterated time-reversal.

    PubMed

    Oberai, Assad A; Feijóo, Gonzalo R; Barbone, Paul E

    2009-02-01

    A new iterative time-reversal algorithm capable of identifying and focusing on multiple scatterers in a relatively small number of iterations is developed. It is recognized that the traditional iterated time-reversal method is based on utilizing power iterations to determine the dominant eigenpairs of the time-reversal operator. The convergence properties of these iterations are known to be suboptimal. Motivated by this, a new method based on Lanczos iterations is developed. In several illustrative examples it is demonstrated that for the same number of transmitted and received signals, the Lanczos iterations based approach is substantially more accurate. PMID:19206835

  17. A comparison of coupling efficiencies for a Stix coil and an m equals 1 coil

    NASA Technical Reports Server (NTRS)

    Sigman, D. R.

    1972-01-01

    This theoretical and experimental study compares the ion-cyclotron wave generating characteristics of a Stix coil (which generates waves with azimuthal mode number m = 0) with those of a coil which produces primarily m = + or -1 ion-cyclotron modes. The theoretical work of J.E. Hipp, which predicted very good coupling for the m = 1 coil, was extended to determine the scaling laws for plasma column radius and coil wavelength. Experimentally, an m = 1 coil and an m = 0 coil were used to generate ion-cyclotron waves on a beam generated plasma column with electron density = 10 to the 12th power/cu cm. Coupling resonances with peak efficiencies of approximately 40 to 50 percent were measured for both coils in low power (approximately 10k W) experiments. For equal power transfer to the plasma, the m = 0 coil voltage was more than a factor of two greater than that for the m = 1 coil.

  18. ITER Scenario Performance Simulations Assessing Control and Vertical Stability

    SciTech Connect

    Casper, T; Ferron, J; Humphreys, D; Jackson, G; Leuer, J; LoDestro, L; Luce, T; Meyer, W; Pearlstein, L; Welander, A

    2008-05-20

    In simulating reference scenarios proposed for ITER operation, we also explore performance of the poloidal field (PF) and central solenoid (CS) coil systems using a controller to maintain plasma shape and vertical stability during the discharge evolution. We employ a combination of techniques to evaluate system constraints and stability using time-dependent transport simulations of ITER discharges. We have begun the process of benchmarking these simulations with experiments on the DIII-D tokamak. Simulations include startup on the outside limiter, X-point formation and current ramp up to full power, plasma burn conditions at 15MA and 17MA, and ramp down at the end of the pulse. We also simulate perturbative events such as H-to-L back transitions. Our results indicate the viability of proposed ITER operating modes.

  19. Non-axisymmetric ideal equilibrium and stability of ITER plasmas with rotating RMPs

    NASA Astrophysics Data System (ADS)

    Ham, C. J.; Cramp, R. G. J.; Gibson, S.; Lazerson, S. A.; Chapman, I. T.; Kirk, A.

    2016-08-01

    The magnetic perturbations produced by the resonant magnetic perturbation (RMP) coils will be rotated in ITER so that the spiral patterns due to strike point splitting which are locked to the RMP also rotate. This is to ensure even power deposition on the divertor plates. VMEC equilibria are calculated for different phases of the RMP rotation. It is demonstrated that the off harmonics rotate in the opposite direction to the main harmonic. This is an important topic for future research to control and optimize ITER appropriately. High confinement mode (H-mode) is favourable for the economics of a potential fusion power plant and its use is planned in ITER. However, the high pressure gradient at the edge of the plasma can trigger periodic eruptions called edge localized modes (ELMs). ELMs have the potential to shorten the life of the divertor in ITER (Loarte et al 2003 Plasma Phys. Control. Fusion 45 1549) and so methods for mitigating or suppressing ELMs in ITER will be important. Non-axisymmetric RMP coils will be installed in ITER for ELM control. Sampling theory is used to show that there will be significant a {{n}\\text{coils}}-{{n}\\text{rmp}} harmonic sideband. There are nine coils toroidally in ITER so {{n}\\text{coils}}=9 . This results in a significant n  =  6 component to the {{n}\\text{rmp}}=3 applied field and a significant n  =  5 component to the {{n}\\text{rmp}}=4 applied field. Although the vacuum field has similar amplitudes of these harmonics the plasma response to the various harmonics dictates the final equilibrium. Magnetic perturbations with toroidal mode number n  =  3 and n  =  4 are applied to a 15 MA, {{q}95}≈ 3 burning ITER plasma. We use a three-dimensional ideal magnetohydrodynamic model (VMEC) to calculate ITER equilibria with applied RMPs and to determine growth rates of infinite n ballooning modes (COBRA). The {{n}\\text{rmp}}=4 case shows little change in ballooning mode growth rate as the RMP is

  20. Iterative Usage of Fixed and Random Effect Models for Powerful and Efficient Genome-Wide Association Studies.

    PubMed

    Liu, Xiaolei; Huang, Meng; Fan, Bin; Buckler, Edward S; Zhang, Zhiwu

    2016-02-01

    False positives in a Genome-Wide Association Study (GWAS) can be effectively controlled by a fixed effect and random effect Mixed Linear Model (MLM) that incorporates population structure and kinship among individuals to adjust association tests on markers; however, the adjustment also compromises true positives. The modified MLM method, Multiple Loci Linear Mixed Model (MLMM), incorporates multiple markers simultaneously as covariates in a stepwise MLM to partially remove the confounding between testing markers and kinship. To completely eliminate the confounding, we divided MLMM into two parts: Fixed Effect Model (FEM) and a Random Effect Model (REM) and use them iteratively. FEM contains testing markers, one at a time, and multiple associated markers as covariates to control false positives. To avoid model over-fitting problem in FEM, the associated markers are estimated in REM by using them to define kinship. The P values of testing markers and the associated markers are unified at each iteration. We named the new method as Fixed and random model Circulating Probability Unification (FarmCPU). Both real and simulated data analyses demonstrated that FarmCPU improves statistical power compared to current methods. Additional benefits include an efficient computing time that is linear to both number of individuals and number of markers. Now, a dataset with half million individuals and half million markers can be analyzed within three days. PMID:26828793

  1. Iterative Usage of Fixed and Random Effect Models for Powerful and Efficient Genome-Wide Association Studies

    PubMed Central

    Liu, Xiaolei; Huang, Meng; Fan, Bin; Buckler, Edward S.; Zhang, Zhiwu

    2016-01-01

    False positives in a Genome-Wide Association Study (GWAS) can be effectively controlled by a fixed effect and random effect Mixed Linear Model (MLM) that incorporates population structure and kinship among individuals to adjust association tests on markers; however, the adjustment also compromises true positives. The modified MLM method, Multiple Loci Linear Mixed Model (MLMM), incorporates multiple markers simultaneously as covariates in a stepwise MLM to partially remove the confounding between testing markers and kinship. To completely eliminate the confounding, we divided MLMM into two parts: Fixed Effect Model (FEM) and a Random Effect Model (REM) and use them iteratively. FEM contains testing markers, one at a time, and multiple associated markers as covariates to control false positives. To avoid model over-fitting problem in FEM, the associated markers are estimated in REM by using them to define kinship. The P values of testing markers and the associated markers are unified at each iteration. We named the new method as Fixed and random model Circulating Probability Unification (FarmCPU). Both real and simulated data analyses demonstrated that FarmCPU improves statistical power compared to current methods. Additional benefits include an efficient computing time that is linear to both number of individuals and number of markers. Now, a dataset with half million individuals and half million markers can be analyzed within three days. PMID:26828793

  2. A noise power spectrum study of a new model-based iterative reconstruction system: Veo 3.0.

    PubMed

    Li, Guang; Liu, Xinming; Dodge, Cristina T; Jensen, Corey T; Rong, X John

    2016-01-01

    The purpose of this study was to evaluate performance of the third generation of model-based iterative reconstruction (MBIR) system, Veo 3.0, based on noise power spectrum (NPS) analysis with various clinical presets over a wide range of clinically applicable dose levels. A CatPhan 600 surrounded by an oval, fat-equivalent ring to mimic patient size/shape was scanned 10 times at each of six dose levels on a GE HD 750 scanner. NPS analysis was performed on images reconstructed with various Veo 3.0 preset combinations for comparisons of those images reconstructed using Veo 2.0, filtered back projection (FBP) and adaptive statistical iterative reconstruc-tion (ASiR). The new Target Thickness setting resulted in higher noise in thicker axial images. The new Texture Enhancement function achieved a more isotropic noise behavior with less image artifacts. Veo 3.0 provides additional reconstruction options designed to allow the user choice of balance between spatial resolution and image noise, relative to Veo 2.0. Veo 3.0 provides more user selectable options and in general improved isotropic noise behavior in comparison to Veo 2.0. The overall noise reduction performance of both versions of MBIR was improved in comparison to FBP and ASiR, especially at low-dose levels. PMID:27685118

  3. Iterative Usage of Fixed and Random Effect Models for Powerful and Efficient Genome-Wide Association Studies.

    PubMed

    Liu, Xiaolei; Huang, Meng; Fan, Bin; Buckler, Edward S; Zhang, Zhiwu

    2016-02-01

    False positives in a Genome-Wide Association Study (GWAS) can be effectively controlled by a fixed effect and random effect Mixed Linear Model (MLM) that incorporates population structure and kinship among individuals to adjust association tests on markers; however, the adjustment also compromises true positives. The modified MLM method, Multiple Loci Linear Mixed Model (MLMM), incorporates multiple markers simultaneously as covariates in a stepwise MLM to partially remove the confounding between testing markers and kinship. To completely eliminate the confounding, we divided MLMM into two parts: Fixed Effect Model (FEM) and a Random Effect Model (REM) and use them iteratively. FEM contains testing markers, one at a time, and multiple associated markers as covariates to control false positives. To avoid model over-fitting problem in FEM, the associated markers are estimated in REM by using them to define kinship. The P values of testing markers and the associated markers are unified at each iteration. We named the new method as Fixed and random model Circulating Probability Unification (FarmCPU). Both real and simulated data analyses demonstrated that FarmCPU improves statistical power compared to current methods. Additional benefits include an efficient computing time that is linear to both number of individuals and number of markers. Now, a dataset with half million individuals and half million markers can be analyzed within three days.

  4. Fully Integrated On-Chip Coil in 0.13 μm CMOS for Wireless Power Transfer Through Biological Media.

    PubMed

    Zargham, Meysam; Gulak, P Glenn

    2015-04-01

    Delivering milliwatts of wireless power at centimeter distances is advantageous to many existing and emerging biomedical applications. It is highly desirable to fully integrate the receiver on a single chip in standard CMOS with no additional post-processing steps or external components. This paper presents a 2 × 2.18 mm(2) on-chip wireless power transfer (WPT) receiver (Rx) coil fabricated in 0.13 μm CMOS. The WPT system utilizes a 14.5 × 14.5 mm(2) transmitter (Tx) coil that is fabricated on a standard FR4 substrate. The on-chip power harvester demonstrates a peak WPT efficiency of -18.47 dB , -20.96 dB and -20.15 dB at 10 mm of separation through air, bovine muscle and 0.2 molar NaCl, respectively. The achieved efficiency enables the delivery of milliwatts of power to application circuits while staying below safe power density and electromagnetic (EM) exposure limits. PMID:25099630

  5. 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.

  6. Scaling of the tokamak near the scrape-off layer H-mode power width and implications for ITER

    NASA Astrophysics Data System (ADS)

    Eich, T.; Leonard, A. W.; Pitts, R. A.; Fundamenski, W.; Goldston, R. J.; Gray, T. K.; Herrmann, A.; Kirk, A.; Kallenbach, A.; Kardaun, O.; Kukushkin, A. S.; LaBombard, B.; Maingi, R.; Makowski, M. A.; Scarabosio, A.; Sieglin, B.; Terry, J.; Thornton, A.; ASDEX Upgrade Team; EFDA Contributors, JET

    2013-09-01

    A multi-machine database for the H-mode scrape-off layer power fall-off length, λq in JET, DIII-D, ASDEX Upgrade, C-Mod, NSTX and MAST has been assembled under the auspices of the International Tokamak Physics Activity. Regression inside the database finds that the most important scaling parameter is the poloidal magnetic field (or equivalently the plasma current), with λq decreasing linearly with increasing Bpol. For the conventional aspect ratio tokamaks, the regression finds \\lambda_{q} \\propto B_{tor}^{-0.8} \\cdot q_{95}^{1.1} \\cdot P_{SOL}^{0.1} \\cdot R_{geo}^{0} , yielding λq,ITER ≅ 1 mm for the baseline inductive H-mode burning plasma scenario at Ip = 15 MA. The experimental divertor target heat flux profile data, from which λq is derived, also yield a divertor power spreading factor (S) which, together with λq, allows an integral power decay length on the target to be estimated. There are no differences in the λq scaling obtained from all-metal or carbon dominated machines and the inclusion of spherical tokamaks has no significant influence on the regression parameters. Comparison of the measured λq with the values expected from a recently published heuristic drift based model shows satisfactory agreement for all tokamaks.

  7. Comparing the bulk radiated power efficiency in carbon and ITER-like-wall environments in JET

    NASA Astrophysics Data System (ADS)

    Devynck, P.; Maddison, G.; Giroud, C.; Jacquet, P.; Lehnen, M.; Lerche, E.; Matthews, G. F.; Neu, R.; Stamp, M. F.; Van Eester, D.; Contributors, JET-EFDA

    2014-07-01

    We use a parameter βr for all plasmas that allows detecting the pollution of the plasma bulk by highly radiative impurities. This parameter is defined as the radiative loss of the mixture of impurities relative to their mean Z2 and was used in previous works to characterize the efficiency of radiative mantles in Neon seeded discharges (Telesca G et al 2000 Nucl. Fusion 40 1845, Carraro L et al 2000 Nucl. Fusion 40 1983). We show that this parameter, though global, is very sensitive to the presence of highly radiative impurities in the bulk of the discharge. We use it to compare JET plasmas in the carbon environment and in the ITER-like wall (ILW), where it is highly correlated to the level of a bundle of spectroscopic lines of tungsten passing through the center of the discharge. In the carbon environment, the value of βr is around 10-40 MW m6, indicating the absence of highly radiative impurities in the plasma. No change or even a small decrease is observed when going from L-mode to H-mode, this robustness being in agreement with the multi-machine scaling (Matthews G F et al 1997 J. Nucl. Mater. 241-243 450). In the ILW machine, the value of βr is found to depend on the type of additional heating and confinement state of the plasma. We observe that neutral-beam injection introduces little W into the plasma, with a βr between 2 × 10-40 and 3 × 10-40 MW m6. Ion-cyclotron radio-frequency waves yield a βr of order 5 in L-mode and 10 × 10-40 MW m6 in H-mode when no edge-localized modes (ELMs) are present. Conversely when ELMs are present, the parameter goes back to 5 × 10-40 MW m6, illustrating the positive effect they can have on the bulk pollution by tungsten.

  8. A study on geometry effect of transmission coil for micro size magnetic induction coil

    NASA Astrophysics Data System (ADS)

    Lee, Kyung Hwa; Jun, Byoung Ok; Kim, Seunguk; Lee, Gwang Jun; Ryu, Mingyu; Choi, Ji-Woong; Jang, Jae Eun

    2016-05-01

    The effects of transmission (Tx) coil structure have been studied for micro-size magnetic induction coil. The size of the receiving (Rx) coil should be shrunk to the micrometer level for the various new applications such as micro-robot and wireless body implanted devices. In case of the macro-scale magnetic induction coil, the power transmission efficiency is generally considered to be higher as the inductance of the transmission coil became larger; however, the large size difference between macro-size Tx coil and micro-size Rx coil can decrease the power transmission efficiency due to the difference of resonance frequency. Here, we study a correlation of the power transmission with the size and distance between the macro-size Tx and micro-size Rx coils using magnetic induction technique. The maximum power efficiency was 0.28/0.23/0.13/0.12% at the distance of 0.3/1/3/5 cm between Rx and Tx coil. In addition, more efficient wireless power transferring method is suggested with a floating coil for the body implantable devices. The voltage output increased up to 5.4 mV than the original one Tx coil system. The results demonstrated the foundational wireless power transferring system with enhanced power efficiency.

  9. Analysis of the phase control of the ITER ICRH antenna array. Influence on the load resilience and radiated power spectrum

    NASA Astrophysics Data System (ADS)

    Messiaen, A.; Swain, D.; Ongena, J.; Vervier, M.

    2015-12-01

    The paper analyses how the phasing of the ITER ICRH 24 strap array evolves from the power sources up to the strap currents of the antenna. The study of the phasing control and coherence through the feeding circuits with prematching and automatic matching and decoupling network is made by modeling starting from the TOPICA matrix of the antenna array for a low coupling plasma profile and for current drive phasing (worst case for mutual coupling effects). The main results of the analysis are: (i) the strap current amplitude is well controlled by the antinode Vmax amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of Vmax of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is ±20°, (iv) the effect on load resilience remains well below the maximum affordable VSWR of the generators, (v) the effect on the radiated power spectrum versus k// computed by means of the coupling code ANTITER II remains small for the considered cases.

  10. Analysis of the phase control of the ITER ICRH antenna array. Influence on the load resilience and radiated power spectrum

    SciTech Connect

    Messiaen, A. Ongena, J.; Vervier, M.; Swain, D.

    2015-12-10

    The paper analyses how the phasing of the ITER ICRH 24 strap array evolves from the power sources up to the strap currents of the antenna. The study of the phasing control and coherence through the feeding circuits with prematching and automatic matching and decoupling network is made by modeling starting from the TOPICA matrix of the antenna array for a low coupling plasma profile and for current drive phasing (worst case for mutual coupling effects). The main results of the analysis are: (i) the strap current amplitude is well controlled by the antinode V{sub max} amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of V{sub max} of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is ±20°, (iv) the effect on load resilience remains well below the maximum affordable VSWR of the generators, (v) the effect on the radiated power spectrum versus k{sub //} computed by means of the coupling code ANTITER II remains small for the considered cases.

  11. Analysis of the phase control of the ITER ICRH antenna array. Influence on the load resilience and radiated power spectrum

    SciTech Connect

    Messiaen, Andre; Swain, David W; Ongena, Jef; Vervier, Michael

    2015-01-01

    The paper analyses how the phasing of the ITER ICRH 24 strap array evolves from the power sources up to the strap currents of the antenna. The study of the phasing control and coherence through the feeding circuits with prematching and automatic matching and decoupling network is made by modeling starting from the TOPICA matrix of the antenna array for a low coupling plasma profile and for current drive phasing (worst case for mutual coupling effects). The main results of the analysis are: (i) the strap current amplitude is well controlled by the antinode V-max amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of V-max of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is +/- 20 degrees, (iv) the effect on load resilience remains well below the maximum affordable VSWR of the generators, (v) the effect on the radiated power spectrum versus k//computed by means of the coupling code ANTITER II remains small for the considered cases. [GRAPHICS] .

  12. Analysis of heat transfer and erosion effects on ITER divertor plasma facing components induced by slow high-power transients

    SciTech Connect

    Federici, G.; Raffray, A.R.; Chiocchio, S.; Esser, B.; Dietz, J.; Igitkhanov, Y.; Janeschitz, G.; Pacher, H.D.; Smid, I.

    1995-12-31

    This paper presents the results of an analysis carried out to investigate the thermal response of ITER divertor plasma facing components (PFC`s) clad with Be, W, and CFC, to high-recycling, high-power thermal transients (i.e. 10--30 MW/m{sup 2}) which are anticipated to last up to a few seconds. The armour erosion and surface melting are estimated for the different plasma facing materials (PFM`s) together with the maximum heat flux to the coolant, and armour/heat-sink interface temperature. The analysis assumes that intense target evaporation will lead to high radiative power losses in the plasma in front of the target which self-protects the target. The cases analyzed clarify the influence of several key parameters such as the plasma heat flux to the target, the loss of the melt layer, the duration of the event, the thickness of the armour, and comparison is made with cases without vapor shielding. Finally, some implications for the performance and lifetime of divertor PFC`s clad with different PFM`s are discussed.

  13. Technical progress in industrial COIL

    NASA Astrophysics Data System (ADS)

    Tei, K.; Sugimoto, Daichi; Ito, T.; Watanabe, G.; Vyskubyenko, O.; Takeuchi, N.; Muto, S.; Fujioka, Tomoo

    2005-03-01

    Chemical oxygen-iodine laser (COIL) has a great potential for applications such as decommissioning and dismantlement (D&D) of nuclear reactor, rock destruction and removal and extraction of a natural resource (Methane hydrate) because of the unique characteristics such as power scalability, high optical beam quality and optical fiber beam. Five-kilowatt Chemical oxygen-iodine laser (COIL) test facility has been developed. The chemical efficiency of 27% has been demonstrated with a moderate beam quality for optical fiber coupling. Our research program contains conventional/ejector-COIL scheme, Jet-SOG/Mist-SOG optimization, fiber delivery and long-term operation.

  14. 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. PMID:25523607

  15. Energetic ions in ITER plasmas

    NASA Astrophysics Data System (ADS)

    Pinches, S. D.; Chapman, I. T.; Lauber, Ph. W.; Oliver, H. J. C.; Sharapov, S. E.; Shinohara, K.; Tani, K.

    2015-02-01

    This paper discusses the behaviour and consequences of the expected populations of energetic ions in ITER plasmas. It begins with a careful analytic and numerical consideration of the stability of Alfvén Eigenmodes in the ITER 15 MA baseline scenario. The stability threshold is determined by balancing the energetic ion drive against the dominant damping mechanisms and it is found that only in the outer half of the plasma ( r / a > 0.5 ) can the fast ions overcome the thermal ion Landau damping. This is in spite of the reduced numbers of alpha-particles and beam ions in this region but means that any Alfvén Eigenmode-induced redistribution is not expected to influence the fusion burn process. The influence of energetic ions upon the main global MHD phenomena expected in ITER's primary operating scenarios, including sawteeth, neoclassical tearing modes and Resistive Wall Modes, is also reviewed. Fast ion losses due to the non-axisymmetric fields arising from the finite number of toroidal field coils, the inclusion of ferromagnetic inserts, the presence of test blanket modules containing ferromagnetic material, and the fields created by the Edge Localised Mode (ELM) control coils in ITER are discussed. The greatest losses and associated heat loads onto the plasma facing components arise due to the use of the ELM control coils and come from neutral beam ions that are ionised in the plasma edge.

  16. Optimized quadrature surface coil designs

    PubMed Central

    Kumar, Ananda; Bottomley, Paul A.

    2008-01-01

    Background Quadrature surface MRI/MRS detectors comprised of circular loop and figure-8 or butterfly-shaped coils offer improved signal-to-noise-ratios (SNR) compared to single surface coils, and reduced power and specific absorption rates (SAR) when used for MRI excitation. While the radius of the optimum loop coil for performing MRI at depth d in a sample is known, the optimum geometry for figure-8 and butterfly coils is not. Materials and methods The geometries of figure-8 and square butterfly detector coils that deliver the optimum SNR are determined numerically by the electromagnetic method of moments. Figure-8 and loop detectors are then combined to create SNR-optimized quadrature detectors whose theoretical and experimental SNR performance are compared with a novel quadrature detector comprised of a strip and a loop, and with two overlapped loops optimized for the same depth at 3 T. The quadrature detection efficiency and local SAR during transmission for the three quadrature configurations are analyzed and compared. Results The SNR-optimized figure-8 detector has loop radius r8 ∼ 0.6d, so r8/r0 ∼ 1.3 in an optimized quadrature detector at 3 T. The optimized butterfly coil has side length ∼ d and crossover angle of ≥ 150° at the center. Conclusions These new design rules for figure-8 and butterfly coils optimize their performance as linear and quadrature detectors. PMID:18057975

  17. Fusion Physics Toward ITER

    NASA Astrophysics Data System (ADS)

    Stambaugh, R. D.

    2006-04-01

    Stars are powered by fusion, the energy released by fusing together light nuclei, using gravitational confinement of plasma. Fusion on earth will be done in a 100 million degree plasma made of deuterium and tritium and confined by magnetic fields or inertia. The worldwide fusion research community will construct ITER, the first experiment that will burn a DT plasma by copious fusion reactions. ITER's nominal goal is to create 500 MW of fusion power. An energy gain of 10 will mean the plasma is dominantly self-heated by the fusion-produced alpha particles. ITER's all superconducting magnet technology and steady-state heat removal technology will enable nominal 400 s pulses to allow the study of burning plasmas on the longest intrinsic timescale of the confined plasma - diffusive redistribution of the electrical currents in the plasma. The advances in magnetic confinement physics that have led to this opportunity will be described, as well as the research opportunities afforded by ITER. The physics of confining stable plasmas and heating them will produce the high gain state in ITER. Sustained burn will come from the physics of controlling currents in plasmas and how the hot plasma is interfaced to its room temperature surroundings. ITER will provide our first experience with how fusion plasma self-heating will profoundly affect the complex, interlinked physical processes that occur in confined plasmas.

  18. 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.

  19. 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.

  20. ENGINEERING OF THE AGS SNAKE COIL ASSEMBLY.

    SciTech Connect

    ANERELLA,M.GUPTA,R.KOVACH,P.MARONE,A.PLATE,S.POWER,K.SCHMALZLE,J.WILLEN,E.

    2003-05-12

    A 30% Snake superconducting magnet is proposed to maintain polarization in the AGS proton beam, the magnetic design of which is described elsewhere. The required helical coils for this magnet push the limits of the technology developed for the RHIC Snake coils. First, fields must be provided with differing pitch along the length of the magnet. To accomplish this, a new 3-D CAD system (''Pro/Engineer'' from PTC), which uses parametric techniques to enable fast iterations, has been employed. Revised magnetic field calculations are then based on the output of the mechanical model. Changes are made in turn to the model on the basis of those field calculations. To ensure that accuracy is maintained, the final solid model is imported directly into the CNC machine programming software, rather than by the use of graphics translating software. Next, due to the large coil size and magnetic field, there was concern whether the structure could contain the coil forces. A finite element analysis was performed, using the 3-D model, to ensure that the stresses and deflections were acceptable. Finally, a method was developed using ultrasonic energy to improve conductor placement during coil winding, in an effort to minimize electrical shorts due to conductor misplacement, a problem that occurred in the RHIC helical coil program. Each of these activities represents a significant improvement in technology over that which was used previously for the RHIC snake coils.

  1. Final Report on ITER Task Agreement 81-10

    SciTech Connect

    Brad J. Merrill

    2009-01-01

    An International Thermonuclear Experimental Reactor (ITER) Implementing Task Agreement (ITA) on Magnet Safety was established between the ITER International Organization (IO) and the Idaho National Laboratory (INL) Fusion Safety Program (FSP) during calendar year 2004. The objectives of this ITA were to add new capabilities to the MAGARC code and to use this updated version of MAGARC to analyze unmitigated superconductor quench events for both poloidal field (PF) and toroidal field (TF) coils of the ITER design. This report documents the completion of the work scope for this ITA. Based on the results obtained for this ITA, an unmitigated quench event in an ITER larger PF coil does not appear to be as severe an accident as in an ITER TF coil.

  2. Toward Construction of ITER

    NASA Astrophysics Data System (ADS)

    Shimomura, Yasuo

    The ITER Project has been significantly developed in the past years in preparation for its construction. The ITER Negotiators have developed a draft Joint Implementation Agreement (JIA), ready for completion following the nomination of the Project’s Director General (DG). The ITER International Team and Participant Teams have continued technical and organizational preparations. The actual construction will be able to start immediately after the international ITER organization will be established, following signature of the JIA. The Project is now strongly supported by all the participants as well as by the scientific community with the final high-level negotiations, focused on siting and the concluding details of cost sharing, started in December 2003. The EU, with Cadarache, and Japan, with Rokkasho, have both promised large contributions to the project to strongly support their construction site proposals. The extent to which they both wish to host the ITER facility is such that large contributions to a broader collaboration among the Parties are also proposed by them. This covers complementary activities to help accelerate fusion development towards a viable power source, as well as may allow the Participants to reach a conclusion on ITER siting.

  3. TRANSP simulations of ITER plasmas

    SciTech Connect

    Budny, R.V.; McCune, D.C.; Redi, M.H.; Schivell, J.; Wieland, R.M.

    1995-12-01

    The TRANSP code is used to construct comprehensive, self-consistent models for ITER discharges. Plasma parameters are studied for two discharges from the ITER ``Interim Design`` database producing 1.5 GW fusion power with a plasma current of 21 MA and 20 toroidal field coils generating 5.7 T Steady state profiles for T{sub ion}, T{sub e}, n{sub e}, Z{sub eff}, and P{sub rad} from the database are specified. TRANSP models the full up/down asymmetric plasma boundary within the separatrix. Effects of high-energy neutral beam injection, sawteeth mixing, toroidal field ripple, and helium ash transport are included. Results are given for the fusion rate profiles, and parameters describing effects such as alpha particle slowing down, the heating of electrons and thermal ions, and the thermalization rates. The deposition of 1 MeV neutral beam ions is predicted to peak near the plasma center, and the average beam ion energy is predicted to be half the injected energy. Sawtooth mixing is predicted to broaden the fast alpha profile. The toroidal ripple losses rate of alpha energy is estimated to be 3% before sawtooth crashes and to increase by a factor of three to four immediately following sawtooth crashes. Assumptions for the thermal He transport and the He recycling coefficient at the boundary are discussed. If the ratio of helium and energy confinement times, {tau}*{sub He}/{tau}{sub E} is less than 15, the steady state fusion power is predicted to 1.5 GW or greater. The values of the transport coefficients required for this fusion power depend on the He recycling coefficient at the separatrix. If R{sub rec} is near 1, the required He diffusivity must be much larger than that measured in tokamaks. If R{sub rec} {le} 0.50, and if the inward pinch is small, values comparable to those measured are compatible with 1.5 GW.

  4. ITER Test Blanket Module Error Field Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Schaffer, M. J.

    2010-11-01

    Recent experiments at DIII-D used an active-coil mock-up to investigate effects of magnetic error fields similar to those expected from two ferromagnetic Test Blanket Modules (TBMs) in one ITER equatorial port. The largest and most prevalent observed effect was plasma toroidal rotation slowing across the entire radial profile, up to 60% in H-mode when the mock-up local ripple at the plasma was ˜4 times the local ripple expected in front of ITER TBMs. Analysis showed the slowing to be consistent with non-resonant braking by the mock-up field. There was no evidence of strong electromagnetic braking by resonant harmonics. These results are consistent with the near absence of resonant helical harmonics in the TBM field. Global particle and energy confinement in H-mode decreased by <20% for the maximum mock-up ripple, but <5% at the local ripple expected in ITER. These confinement reductions may be linked with the large velocity reductions. TBM field effects were small in L-mode but increased with plasma beta. The L-H power threshold was unaffected within error bars. The mock-up field increased plasma sensitivity to mode locking by a known n=1 test field (n = toroidal harmonic number). In H-mode the increased locking sensitivity was from TBM torque slowing plasma rotation. At low beta, locked mode tolerance was fully recovered by re-optimizing the conventional DIII-D ``I-coils'' empirical compensation of n=1 errors in the presence of the TBM mock-up field. Empirical error compensation in H-mode should be addressed in future experiments. Global loss of injected neutral beam fast ions was within error bars, but 1 MeV fusion triton loss may have increased. The many DIII-D mock-up results provide important benchmarks for models needed to predict effects of TBMs in ITER.

  5. Error Field Correction in ITER

    SciTech Connect

    Park, Jong-kyu; Boozer, Allen H.; Menard, Jonathan E.; Schaffer, Michael J.

    2008-05-22

    A new method for correcting magnetic field errors in the ITER tokamak is developed using the Ideal Perturbed Equilibrium Code (IPEC). The dominant external magnetic field for driving islands is shown to be localized to the outboard midplane for three ITER equilibria that represent the projected range of operational scenarios. The coupling matrices between the poloidal harmonics of the external magnetic perturbations and the resonant fields on the rational surfaces that drive islands are combined for different equilibria and used to determine an ordered list of the dominant errors in the external magnetic field. It is found that efficient and robust error field correction is possible with a fixed setting of the correction currents relative to the currents in the main coils across the range of ITER operating scenarios that was considered.

  6. 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.

  7. Eight channel transmit array volume coil using on-coil radiofrequency current sources

    PubMed Central

    Kurpad, Krishna N.; Boskamp, Eddy B.

    2014-01-01

    Background At imaging frequencies associated with high-field MRI, the combined effects of increased load-coil interaction and shortened wavelength results in degradation of circular polarization and B1 field homogeneity in the imaging volume. Radio frequency (RF) shimming is known to mitigate the problem of B1 field inhomogeneity. Transmit arrays with well decoupled transmitting elements enable accurate B1 field pattern control using simple, non-iterative algorithms. Methods An eight channel transmit array was constructed. Each channel consisted of a transmitting element driven by a dedicated on-coil RF current source. The coil current distributions of characteristic transverse electromagnetic (TEM) coil resonant modes were non-iteratively set up on each transmitting element and 3T MRI images of a mineral oil phantom were obtained. Results B1 field patterns of several linear and quadrature TEM coil resonant modes that typically occur at different resonant frequencies were replicated at 128 MHz without having to retune the transmit array. The generated B1 field patterns agreed well with simulation in most cases. Conclusions Independent control of current amplitude and phase on each transmitting element was demonstrated. The transmit array with on-coil RF current sources enables B1 field shimming in a simple and predictable manner. PMID:24834418

  8. ITER Fusion Energy

    ScienceCinema

    Dr. Norbert Holtkamp

    2016-07-12

    ITER (in Latin “the way”) is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier over one and thus release energy. In the fusion process two isotopes of hydrogen – deuterium and tritium – fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q ? 10 (input power 50 MW / output power 500 MW). The ITER Organization was officially established in Cadarache, France, on 24 October 2007. The seven members engaged in the project – China, the European Union, India, Japan, Korea, Russia and the United States – represent more than half the world’s population. The costs for ITER are shared by the seven members. The cost for the construction will be approximately 5.5 billion Euros, a similar amount is foreseen for the twenty-year phase of operation and the subsequent decommissioning.

  9. Resistive demountable toroidal-field coils for tokamak reactors

    SciTech Connect

    Jassby, D.L.; Jacobsen, R.A.; Kalnavarns, J.; Masson, L.S.; Sekot, J.P.

    1981-07-01

    Readily demountable TF (toroidal-field) coils allow complete access to the internal components of a tokamak reactor for maintenance of replacement. The requirement of readily demountable joints dictates the use of water-cooled resistive coils, which have a host of decisive advantages over superconducting coils. Previous papers have shown that resistive TF coils for tokamak reactors can operate in the steady state with acceptable power dissipation (typically, 175 to 300 MW). This paper summarizes results of parametric studies of size optimization of rectangular TF coils and of a finite-element stress analysis, and examines several candidate methods of implementing demountable joints for rectangular coils constructed of plate segments.

  10. 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.

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

    PubMed

    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. PMID:26852418

  12. Magnet design technical report---ITER definition phase

    SciTech Connect

    Henning, C.

    1989-04-28

    This report contains papers on the following topics: conceptual design; radiation damage of ITER magnet systems; insulation system of the magnets; critical current density and strain sensitivity; toroidal field coil structural analysis; stress analysis for the ITER central solenoid; and volt-second capabilities and PF magnet configurations.

  13. Open coil structure for bubble-memory-device packaging

    NASA Technical Reports Server (NTRS)

    Chen, T. T.; Ypma, J. E.

    1975-01-01

    Concept has several important advantages over close-wound system: memory and coil chips are separate and interchangeable; interconnections in coil level are eliminated by packing memory chip and electronics in single structure; and coil size can be adjusted to optimum value in terms of power dissipation and field uniformity.

  14. A Figure-of-Merit for Designing High-Performance Inductive Power Transmission Links

    PubMed Central

    Kiani, Mehdi; Ghovanloo, Maysam

    2014-01-01

    Power transfer efficiency (PTE) and power delivered to the load (PDL) are two key inductive link design parameters that relate to the power source and driver specs, power loss, transmission range, robustness against misalignment, variations in loading, and interference with other devices. Designers need to strike a delicate balance between these two because designing the link to achieve high PTE will degrade the PDL and vice versa. We are proposing a new figure-of-merit (FoM), which can help designers to find out whether a two-, three-, or four-coil link is appropriate for their particular application and guide them through an iterative design procedure to reach optimal coil geometries based on how they weigh the PTE versus PDL for that application. Three design examples at three different power levels have been presented based on the proposed FoM for implantable microelectronic devices, handheld mobile devices, and electric vehicles. The new FoM suggests that the two-coil links are suitable when the coils are strongly coupled, and a large PDL is needed. Three-coil links are the best when the coils are loosely coupled, the coupling distance varies considerably, and large PDL is necessary. Finally, four-coil links are optimal when the PTE is paramount, the coils are loosely coupled, and their relative distance and alignment are stable. Measurement results support the accuracy of the theoretical design procedure and conclusions. PMID:25382898

  15. Geometrical Design of a Scalable Overlapping Planar Spiral Coil Array to Generate a Homogeneous Magnetic Field

    PubMed Central

    Jow, Uei-Ming; Ghovanloo, Maysam

    2014-01-01

    We present a design methodology for an overlapping hexagonal planar spiral coil (hex-PSC) array, optimized for creation of a homogenous magnetic field for wireless power transmission to randomly moving objects. The modular hex-PSC array has been implemented in the form of three parallel conductive layers, for which an iterative optimization procedure defines the PSC geometries. Since the overlapping hex-PSCs in different layers have different characteristics, the worst case coil-coupling condition should be designed to provide the maximum power transfer efficiency (PTE) in order to minimize the spatial received power fluctuations. In the worst case, the transmitter (Tx) hex-PSC is overlapped by six PSCs and surrounded by six other adjacent PSCs. Using a receiver (Rx) coil, 20 mm in radius, at the coupling distance of 78 mm and maximum lateral misalignment of 49.1 mm (1/√3 of the PSC radius) we can receive power at a PTE of 19.6% from the worst case PSC. Furthermore, we have studied the effects of Rx coil tilting and concluded that the PTE degrades significantly when θ > 60°. Solutions are: 1) activating two adjacent overlapping hex-PSCs simultaneously with out-of-phase excitations to create horizontal magnetic flux and 2) inclusion of a small energy storage element in the Rx module to maintain power in the worst case scenarios. In order to verify the proposed design methodology, we have developed the EnerCage system, which aims to power up biological instruments attached to or implanted in freely behaving small animal subjects’ bodies in long-term electrophysiology experiments within large experimental arenas. PMID:24782576

  16. Wedding ring shaped excitation coil

    DOEpatents

    MacLennan, Donald A.; Tsai, Peter

    2001-01-01

    A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and/or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency.

  17. Electromagnetic pump stator coil

    DOEpatents

    Fanning, Alan W.; Dahl, Leslie R.

    1996-01-01

    An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom.

  18. Electromagnetic pump stator coil

    DOEpatents

    Fanning, A.W.; Dahl, L.R.

    1996-06-25

    An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom. 9 figs.

  19. a Study on Correlation Between Jc(4.2 k) and Current Sharing Temperature Tcs of Nb3Sn Strands and Short Sample of Conductor for Toroidal Field Coils of Iter Magnet System

    NASA Astrophysics Data System (ADS)

    Shikov, A. K.; Pantsyrny, V. I.; Kozlenkova, N. I.; Vasilyev, R. M.; Vorobieva, A. E.; Mareev, K. A.; Sudijev, S. V.

    2010-04-01

    One of the main requirements for ITER Nb3Sn Toroidal Field (TF) conductor is a temperature margin of 0.7 K under 11.8 T peak field, 68 kA operating current, and operating temperature of 5 K, i.e. current sharing temperature Tcs = 5.7 K, while the performance of Nb3Sn strands used for the fabrication of the conductor is evaluated by critical current density Jc(4.2 K, 12 T). This work represents an analysis of experimentally revealed correlation between Jc(4.2 K, 12 T) and Tcs of several Nb3Sn strands and short sample of the TF conductor RFTF2 tested in SULTAN facility (SULTAN sample). The performance of the strands used for SULTAN sample fabrication is investigated in details. The paper includes the analysis of voltage-current and voltage-temperature characteristics. An assessment of strain influence on the performance and transition parameters (n and T0) of the strands is also presented. The results obtained for strands are compared with the test results of SULTAN sample RFTF2.

  20. Predicting coiled coils by use of pairwise residue correlations.

    PubMed Central

    Berger, B; Wilson, D B; Wolf, E; Tonchev, T; Milla, M; Kim, P S

    1995-01-01

    A method is presented that predicts coiled-coil domains in protein sequences by using pairwise residue correlations obtained from a (two-stranded) coiled-coil database of 58,217 amino acid residues. A program called PAIRCOIL implements this method and is significantly better than existing methods at distinguishing coiled coils from alpha-helices that are not coiled coils. The database of pairwise residue correlations suggests structural features that stabilize or destabilize coiled coils. Images Fig. 1 Fig. 2 PMID:7667278

  1. Challenges and status of ITER conductor production

    NASA Astrophysics Data System (ADS)

    Devred, A.; Backbier, I.; Bessette, D.; Bevillard, G.; Gardner, M.; Jong, C.; Lillaz, F.; Mitchell, N.; Romano, G.; Vostner, A.

    2014-04-01

    Taking the relay of the large Hadron collider (LHC) at CERN, ITER has become the largest project in applied superconductivity. In addition to its technical complexity, ITER is also a management challenge as it relies on an unprecedented collaboration of seven partners, representing more than half of the world population, who provide 90% of the components as in-kind contributions. The ITER magnet system is one of the most sophisticated superconducting magnet systems ever designed, with an enormous stored energy of 51 GJ. It involves six of the ITER partners. The coils are wound from cable-in-conduit conductors (CICCs) made up of superconducting and copper strands assembled into a multistage cable, inserted into a conduit of butt-welded austenitic steel tubes. The conductors for the toroidal field (TF) and central solenoid (CS) coils require about 600 t of Nb3Sn strands while the poloidal field (PF) and correction coil (CC) and busbar conductors need around 275 t of Nb-Ti strands. The required amount of Nb3Sn strands far exceeds pre-existing industrial capacity and has called for a significant worldwide production scale up. The TF conductors are the first ITER components to be mass produced and are more than 50% complete. During its life time, the CS coil will have to sustain several tens of thousands of electromagnetic (EM) cycles to high current and field conditions, way beyond anything a large Nb3Sn coil has ever experienced. Following a comprehensive R&D program, a technical solution has been found for the CS conductor, which ensures stable performance versus EM and thermal cycling. Productions of PF, CC and busbar conductors are also underway. After an introduction to the ITER project and magnet system, we describe the ITER conductor procurements and the quality assurance/quality control programs that have been implemented to ensure production uniformity across numerous suppliers. Then, we provide examples of technical challenges that have been encountered and

  2. FIRST 100 T NON-DESTRUCTIVE MAGNET OUTER COIL SET

    SciTech Connect

    J. BACON; A. BACA; ET AL

    1999-09-01

    The controlled power outer coil set of the first 100 T non-destructive (100 T ND) magnet is described. This magnet will be installed as part of the user facility research equipment at the National High Magnetic Field laboratory (NHMFL) Pulsed Field Facility at Los Alamos National Laboratory. The 100 T ND controlled power outer coil set consists of seven nested, mechanically independent externally reinforced coils. These coils, in combination, will produce a 47 T platform field in a 225-mm diameter bore. Using inertial energy storage a synchronous motor/generator provides ac power to a set of seven ac-dc converters rated at 64 MW/80 MVA each. These converters energize three independent coil circuits to create 170 MJ of field energy in the outer coil set at the platform field of 47 T. Each coil consists of a multi-layer winding of high strength conductor supported by an external high strength stainless steel shell. Coils with the highest magnetic loads will utilize a reinforcing shell fabricated from highly cold worked 301 stainless steel strip. The autofrettage conditioning method will be used to pre-stress the coils and thereby limit conductor and reinforcement strains to the elastic range. The purpose of pre-stressing the coils is to attain a design life of 10,000 full field pulses. The operation and conditioning of the coil set will be described along with special features of its design, magnetic and structural analyses and construction.

  3. Boundary plasma modelling for ITER

    SciTech Connect

    Braams, B.J.

    1993-01-01

    Computer programs were developed to model the effect of nonaxisymmetric magnetic perturbations upon divertor heat load, and have explored what kind of externally applied perturbations are the most effective for heat load reduction without destroying core plasma confinement. We find that a carefully tuned set of coils located about 0.3 m outside the separatrix can be used to spread the heat load over about 0.1 m perpendicular to flux surfaces at the ITER divertor plate, even at a very low level of anomalous cross-field heat transport. As such a spreading would significantly extend the permissible regime of operation for ITER, we recommend that this study be pursued at the level of detail required for engineering design. In other work under this grant we are in the process of modifying the B2 code to handle correctly a non-orthogonal geometry.

  4. Segmented Coil Fails In Steps

    NASA Technical Reports Server (NTRS)

    Stedman, Ronald S.

    1990-01-01

    Electromagnetic coil degrades in steps when faults occur, continues to operate at reduced level instead of failing catastrophically. Made in segments connected in series and separated by electrically insulating barriers. Fault does not damage adjacent components or create hazard. Used to control valves in such critical applications as cooling systems of power generators and chemical process equipment, where flammable liquids or gases handled. Also adapts to electrical control of motors.

  5. Superconducting magnetic coil

    DOEpatents

    Aized, Dawood; Schwall, Robert E.

    1996-06-11

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

  6. Superconducting magnetic coil

    DOEpatents

    Aized, Dawood; Schwall, Robert E.

    1999-06-22

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

  7. Superconducting magnetic coil

    DOEpatents

    Aized, D.; Schwall, R.E.

    1999-06-22

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil. 15 figs.

  8. Advanced COIL technologies for field applications

    NASA Astrophysics Data System (ADS)

    Tei, Kazuyoku; Sugimoto, Daichi; Ito, T.; Watanabe, G.; Vyskubenko, O.; Takeuchi, N.; Muto, S.; Kenzo, N.; Fujioka, Tomoo

    2005-01-01

    Chemical oxygen-iodine laser (COIL) has a great potential for applications such as decommissioning and dismantlement (D&D) of nuclear reactor, rock destruction and removal and extraction of a natural resource (Methane hydrate) because of the unique characteristics such as power scalability, high optical beam quality and optical fiber beam. Five-kilowatt Chemical oxygen-iodine laser (COIL) test facility has been developed. The chemical efficiency of 27% has been demonstrated with a moderate beam quality for optical fiber coupling. Our research program contains conventional/ejector-COIL scheme, Jet-SOG/Mist-SOG optimization, fiber delivery and long-term operation.

  9. Flat RF coils in static field gradient nuclear magnetic resonance.

    PubMed

    Stork, H; Gädke, A; Nestle, N; Fujara, F

    2009-10-01

    The use of flat RF coils allows considerable gains in the sensitivity of static field gradient (SFG) nuclear magnetic resonance (NMR) experiments. In this article, this effect is studied theoretically as well as experimentally. Additionally, the flat coil geometry has been studied theoretically depending on magnetic field gradient, pulse sequence and amplifier power. Moreover, detecting the signal directly from the free induction decay (FID) turned out to be quite attractive for STRAFI-like microimaging experiments, especially when using flat coils. In addition to wound rectangular flat coils also spiral flat coils have been developed which can be manufactured by photolithography from printed circuit boards.

  10. Progress on the application of ELM control schemes to ITER scenarios from the non-active phase to DT operation

    NASA Astrophysics Data System (ADS)

    Loarte, A.; Huijsmans, G.; Futatani, S.; Baylor, L. R.; Evans, T. E.; Orlov, D. M.; Schmitz, O.; Becoulet, M.; Cahyna, P.; Gribov, Y.; Kavin, A.; Sashala Naik, A.; Campbell, D. J.; Casper, T.; Daly, E.; Frerichs, H.; Kischner, A.; Laengner, R.; Lisgo, S.; Pitts, R. A.; Saibene, G.; Wingen, A.

    2014-03-01

    Progress in the definition of the requirements for edge localized mode (ELM) control and the application of ELM control methods both for high fusion performance DT operation and non-active low-current operation in ITER is described. Evaluation of the power fluxes for low plasma current H-modes in ITER shows that uncontrolled ELMs will not lead to damage to the tungsten (W) divertor target, unlike for high-current H-modes in which divertor damage by uncontrolled ELMs is expected. Despite the lack of divertor damage at lower currents, ELM control is found to be required in ITER under these conditions to prevent an excessive contamination of the plasma by W, which could eventually lead to an increased disruptivity. Modelling with the non-linear MHD code JOREK of the physics processes determining the flow of energy from the confined plasma onto the plasma-facing components during ELMs at the ITER scale shows that the relative contribution of conductive and convective losses is intrinsically linked to the magnitude of the ELM energy loss. Modelling of the triggering of ELMs by pellet injection for DIII-D and ITER has identified the minimum pellet size required to trigger ELMs and, from this, the required fuel throughput for the application of this technique to ITER is evaluated and shown to be compatible with the installed fuelling and tritium re-processing capabilities in ITER. The evaluation of the capabilities of the ELM control coil system in ITER for ELM suppression is carried out (in the vacuum approximation) and found to have a factor of ˜2 margin in terms of coil current to achieve its design criterion, although such a margin could be substantially reduced when plasma shielding effects are taken into account. The consequences for the spatial distribution of the power fluxes at the divertor of ELM control by three-dimensional (3D) fields are evaluated and found to lead to substantial toroidal asymmetries in zones of the divertor target away from the separatrix

  11. RMP ELM suppression in DIII-D plasmas with ITER similar shapes and collisionalities

    NASA Astrophysics Data System (ADS)

    Evans, T. E.; Fenstermacher, M. E.; Moyer, R. A.; Osborne, T. H.; Watkins, J. G.; Gohil, P.; Joseph, I.; Schaffer, M. J.; Baylor, L. R.; Bécoulet, M.; Boedo, J. A.; Burrell, K. H.; de Grassie, J. S.; Finken, K. H.; Jernigan, T.; Jakubowski, M. W.; Lasnier, C. J.; Lehnen, M.; Leonard, A. W.; Lonnroth, J.; Nardon, E.; Parail, V.; Schmitz, O.; Unterberg, B.; West, W. P.

    2008-02-01

    Large Type-I edge localized modes (ELMs) are completely eliminated with small n = 3 resonant magnetic perturbations (RMP) in low average triangularity, \\bar {\\delta }=0.26 , plasmas and in ITER similar shaped (ISS) plasmas, \\bar {\\delta }=0.53 , with ITER relevant collisionalities v_e^\\ast \\le 0.2 . Significant differences in the RMP requirements and in the properties of the ELM suppressed plasmas are found when comparing the two triangularities. In ISS plasmas, the current required to suppress ELMs is approximately 25% higher than in low average triangularity plasmas. It is also found that the width of the resonant q95 window required for ELM suppression is smaller in ISS plasmas than in low average triangularity plasmas. An analysis of the positions and widths of resonant magnetic islands across the pedestal region, in the absence of resonant field screening or a self-consistent plasma response, indicates that differences in the shape of the q profile may explain the need for higher RMP coil currents during ELM suppression in ISS plasmas. Changes in the pedestal profiles are compared for each plasma shape as well as with changes in the injected neutral beam power and the RMP amplitude. Implications of these results are discussed in terms of requirements for optimal ELM control coil designs and for establishing the physics basis needed in order to scale this approach to future burning plasma devices such as ITER.

  12. 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.

  13. Thermoeconomic analysis of a CHP system by iterative numerical techniques

    SciTech Connect

    Damshala, P.R.

    2000-07-01

    This paper deals with the determination of the thermoeconomic optimum conditions for a constant space heat load imposed on the air coil of a combined heating and power (CHP) system using iterative numerical techniques. From the thermodynamic relations and equations derived from the energy balance and heat exchanger characteristics, an objective function and constraining equations are obtained. A computer program is developed based on the Redlich-Kwong equation of state to estimate the thermodynamic properties of the refrigerant fluid R-22. Additional computer subroutines are developed to perform thermodynamic and thermoeconomic optimization. Optimum values of the operating variables are identified at thermodynamic and thermoeconomic optimum conditions. Results show that the total irreversibilities produced in the system and the cost of fuel consumption are minimum at thermodynamic optimum conditions, but the annual cost of owning and operating the system is minimum at the thermoeconomic optimum condition, which is 34% lower than at the thermodynamic optimum condition.

  14. Neutron activation for ITER

    SciTech Connect

    Barnes, C.W.; Loughlin, M.J.; Nishitani, Takeo

    1996-04-29

    There are three primary goals for the Neutron Activation system for ITER: maintain a robust relative measure of fusion power with stability and high dynamic range (7 orders of magnitude); allow an absolute calibration of fusion power (energy); and provide a flexible and reliable system for materials testing. The nature of the activation technique is such that stability and high dynamic range can be intrinsic properties of the system. It has also been the technique that demonstrated (on JET and TFTR) the highest accuracy neutron measurements in DT operation. Since the gamma-ray detectors are not located on the tokamak and are therefore amenable to accurate characterization, and if material foils are placed very close to the ITER plasma with minimum scattering or attenuation, high overall accuracy in the fusion energy production (7--10%) should be achievable on ITER. In the paper, a conceptual design is presented. A system is shown to be capable of meeting these three goals, also detailed design issues remain to be solved.

  15. Coiled bodies without coilin.

    PubMed Central

    Bauer, D W; Gall, J G

    1997-01-01

    Nuclei assembled in vitro in Xenopus egg extract contain coiled bodies that have components from three different RNA processing pathways: pre-mRNA splicing, pre-rRNA processing, and histone pre-mRNA 3'-end formation. In addition, they contain SPH-1, the Xenopus homologue of p80-coilin, a protein characteristic of coiled bodies. To determine whether coilin is an essential structural component of the coiled body, we removed it from the egg extract by immunoprecipitation. We showed that nuclei with bodies morphologically identical to coiled bodies (at the light microscope level) formed in such coilin-depleted extract. As expected, these bodies did not stain with antibodies against coilin. Moreover, they failed to stain with an antibody against the Sm proteins, although Sm proteins associated with snRNAs were still present in the extract. Staining of the coilin- and Sm-depleted coiled bodies was normal with antibodies against two nucleolar proteins, fibrillarin and nucleolin. Similar results were observed when Sm proteins were depleted from egg extract: staining of the coiled bodies with antibodies against the Sm proteins and coilin was markedly reduced but bright nucleolin and fibrillarin staining remained. These immunodepletion experiments demonstrate an interdependence between coilin and Sm snRNPs and suggest that neither is essential for assembly of nucleolar components in coiled bodies. We propose that coiled bodies are structurally heterogeneous organelles in which the components of the three RNA processing pathways may occur in separate compartments. Images PMID:9017596

  16. New radiant coil technology

    SciTech Connect

    Yonezawa, M.; Amano, T.; Maruta, T.; Wall, F.

    1983-12-01

    This article demonstrates how the retrofitting of an ethylene furnace by replacing pyrolysis coils with a new design sharply improved its performance. The revamped furnace was designed and built for a 300,000 MTA (metric ton/yr) ethylene plant in the early 70s. Basic design considerations for the furnace were the use of high-severity cracking to provide high C/sub 2/H/sub 4/ and total olefin yields; by a careful selection of pyrolysis coil dimensions and materials, the coil was equipped with feedstock flexibility; and the furnace can handle four different gas fuels and two different liquid fuels. The furnace is a vertical twin-cell type with induced draft fans, and its four-pass pyrolysis coils (vertical/and single diameter) are arranged in a double staggered row. The cracked gas streams from the four-pass coils are combined at the furnace outlet by a special fitting and exit the furnace.

  17. Comparison of an Electromagnetic Energy Harvester Performance using Wound Coil Wire and PCB Coil

    NASA Astrophysics Data System (ADS)

    Resali, MSM; Salleh, H.

    2016-03-01

    This paper presents the performance of two types of electromagnetic energy harvester, one using manually wound coil wire (EH-EC) and the other one using printed circuit board (PCB) coil (EH-EP). The objective of the study is to measure the corresponding output voltage and power by varying the number of coils and the position of the magnet. The experiment was conducted at a fix 50 Hz of frequency and at 0.25g of acceleration. The EH-EP was found to be more effective than the 350 turns of the wound coil wire, with maximum power of 26 μW. Overall, the performance of the EH-EC showed better result with maximum power of 125 μW for 1050 turns when compared to the EH-EP.

  18. DIII-D research towards resolving key issues for ITER and steady-state tokamaks

    NASA Astrophysics Data System (ADS)

    Hill, D. N.; the DIII-D Team

    2013-10-01

    The DIII-D research program is addressing key ITER research needs and developing the physics basis for future steady-state tokamaks. Pellet pacing edge-localized mode (ELM) control in the ITER configuration reduces ELM energy loss in proportion to 1/fpellet by inducing ELMs at up to 12× the natural ELM rate. Complete suppression of ELMs with resonant magnetic perturbations has been extended to the q95 expected for ITER baseline scenario discharges, and long-duration ELM-free QH-mode discharges have been produced with ITER-relevant co-current neutral-beam injection (NBI) using external n = 3 coils to generate sufficient counter-Ip torque. ITER baseline discharges at βN ˜ 2 and scaled NBI torque have been maintained in stationary conditions for more than four resistive times using electron cyclotron current drive (ECCD) for tearing mode suppression and disruption avoidance; active tracking with steerable launchers and feedback control catch these modes at small amplitude, reducing the ECCD power required to suppress them. Massive high-Z gas injection into disruption-induced 300-600 kA 20 MeV runaway electron (RE) beams yield dissipation rates ˜10× faster than expected from e-e collisions and demonstrate the possibility of benign dissipation of such REs should they occur in ITER. Other ITER-related experiments show measured intrinsic plasma torque in good agreement with a physics-based model over a wide range of conditions, while first-time main-ion rotation measurements show it to be lower than expected from neoclassical theory. Core turbulence measurements show increased temperature fluctuations correlated with sharply enhanced electron transport when \

  19. An exploration of advanced X-divertor scenarios on ITER

    NASA Astrophysics Data System (ADS)

    Covele, B.; Valanju, P.; Kotschenreuther, M.; Mahajan, S.

    2014-07-01

    It is found that the X-divertor (XD) configuration (Kotschenreuther et al 2004 Proc. 20th Int. Conf. on Fusion Energy (Vilamoura, Portugal, 2004) (Vienna: IAEA) CD-ROM file [IC/P6-43] www-naweb.iaea.org/napc/physics/fec/fec2004/datasets/index.html, Kotschenreuther et al 2006 Proc. 21st Int. Conf. on Fusion Energy 2006 (Chengdu, China, 2006) (Vienna: IAEA), CD-ROM file [IC/P7-12] www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/index.htm, Kotschenreuther et al 2007 Phys. Plasmas 14 072502) can be made with the conventional poloidal field (PF) coil set on ITER (Tomabechi et al and Team 1991 Nucl. Fusion 31 1135), where all PF coils are outside the TF coils. Starting from the standard divertor, a sequence of desirable XD configurations are possible where the PF currents are below the present maximum design limits on ITER, and where the baseline divertor cassette is used. This opens the possibility that the XD could be tested and used to assist in high-power operation on ITER, but some further issues need examination. Note that the increased major radius of the super-X-divertor (Kotschenreuther et al 2007 Bull. Am. Phys. Soc. 53 11, Valanju et al 2009 Phys. Plasmas 16 5, Kotschenreuther et al 2010 Nucl. Fusion 50 035003, Valanju et al 2010 Fusion Eng. Des. 85 46) is not a feature of the XD geometry. In addition, we present an XD configuration for K-DEMO (Kim et al 2013 Fusion Eng. Des. 88 123) to demonstrate that it is also possible to attain the XD configuration in advanced tokamak reactors with all PF coils outside the TF coils. The results given here for the XD are far more encouraging than recent calculations by Lackner and Zohm (2012 Fusion Sci. Technol. 63 43) for the Snowflake (Ryutov 2007 Phys. Plasmas 14 064502, Ryutov et al 2008 Phys. Plasmas 15 092501), where the required high PF currents represent a major technological challenge. The magnetic field structure in the outboard divertor SOL (Kotschenreuther 2013 Phys. Plasmas 20 102507) in the recently created

  20. Self-sorting heterodimeric coiled coil peptides with defined and tuneable self-assembly properties

    PubMed Central

    Aronsson, Christopher; Dånmark, Staffan; Zhou, Feng; Öberg, Per; Enander, Karin; Su, Haibin; Aili, Daniel

    2015-01-01

    Coiled coils with defined assembly properties and dissociation constants are highly attractive components in synthetic biology and for fabrication of peptide-based hybrid nanomaterials and nanostructures. Complex assemblies based on multiple different peptides typically require orthogonal peptides obtained by negative design. Negative design does not necessarily exclude formation of undesired species and may eventually compromise the stability of the desired coiled coils. This work describe a set of four promiscuous 28-residue de novo designed peptides that heterodimerize and fold into parallel coiled coils. The peptides are non-orthogonal and can form four different heterodimers albeit with large differences in affinities. The peptides display dissociation constants for dimerization spanning from the micromolar to the picomolar range. The significant differences in affinities for dimerization make the peptides prone to thermodynamic social self-sorting as shown by thermal unfolding and fluorescence experiments, and confirmed by simulations. The peptides self-sort with high fidelity to form the two coiled coils with the highest and lowest affinities for heterodimerization. The possibility to exploit self-sorting of mutually complementary peptides could hence be a viable approach to guide the assembly of higher order architectures and a powerful strategy for fabrication of dynamic and tuneable nanostructured materials. PMID:26370878

  1. US--ITER activation analysis

    SciTech Connect

    Attaya, H.; Gohar, Y.; Smith, D.

    1990-09-01

    Activation analysis has been made for the US ITER design. The radioactivity and the decay heat have been calculated, during operation and after shutdown for the two ITER phases, the Physics Phase and the Technology Phase. The Physics Phase operates about 24 full power days (FPDs) at fusion power level of 1100 MW and the Technology Phase has 860 MW fusion power and operates for about 1360 FPDs. The point-wise gamma sources have been calculated everywhere in the reactor at several times after shutdown of the two phases and are then used to calculate the biological dose everywhere in the reactor. Activation calculations have been made also for ITER divertor. The results are presented for different continuous operation times and for only one pulse. The effect of the pulsed operation on the radioactivity is analyzed. 6 refs., 12 figs., 1 tab.

  2. Correction coil cable

    DOEpatents

    Wang, S.T.

    1994-11-01

    A wire cable assembly adapted for the winding of electrical coils is taught. A primary intended use is for use in particle tube assemblies for the Superconducting Super Collider. The correction coil cables have wires collected in wire array with a center rib sandwiched therebetween to form a core assembly. The core assembly is surrounded by an assembly housing having an inner spiral wrap and a counter wound outer spiral wrap. An alternate embodiment of the invention is rolled into a keystoned shape to improve radial alignment of the correction coil cable on a particle tube in a particle tube assembly. 7 figs.

  3. ELECTRICAL COIL STRUCTURE

    DOEpatents

    Baker, W.R.; Hartwig, A.

    1962-09-25

    A compactly wound electrical coil is designed for carrying intense pulsed currents such as are characteristic of controlled thermonuclear reaction devices. A flat strip of conductor is tightly wound in a spiral with a matching flat strip of insulator. To provide for a high fluid coolant flow through the coil with minimum pumping pressure, a surface of the conductor is scored with parallel transverse grooves which form short longitudinal coolant pasaages when the conductor is wound in the spiral configuration. Owing to this construction, the coil is extremely resistant to thermal and magnetic shock from sudden high currents. (AEC)

  4. 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.

  5. Magnetic microhelix coil structures.

    PubMed

    Smith, Elliot J; Makarov, Denys; Sanchez, Samuel; Fomin, Vladimir M; Schmidt, Oliver G

    2011-08-26

    Together with the well-known ferro- and antiferromagnetic ordering, nature has created a variety of complex helical magnetic configurations. Here, we design and investigate three-dimensional microhelix coil structures that are radial-, corkscrew-, and hollow-bar-magnetized. The magnetization configurations of the differently magnetized coils are experimentally revealed by probing their specific dynamic response to an external magnetic field. Helix coils offer an opportunity to realize microscale geometries of the magnetic toroidal moment, observed so far only in bulk multiferroic materials. PMID:21929266

  6. Magnetic Microhelix Coil Structures

    NASA Astrophysics Data System (ADS)

    Smith, Elliot J.; Makarov, Denys; Sanchez, Samuel; Fomin, Vladimir M.; Schmidt, Oliver G.

    2011-08-01

    Together with the well-known ferro- and antiferromagnetic ordering, nature has created a variety of complex helical magnetic configurations. Here, we design and investigate three-dimensional microhelix coil structures that are radial-, corkscrew-, and hollow-bar-magnetized. The magnetization configurations of the differently magnetized coils are experimentally revealed by probing their specific dynamic response to an external magnetic field. Helix coils offer an opportunity to realize microscale geometries of the magnetic toroidal moment, observed so far only in bulk multiferroic materials.

  7. A first characterization of the quench detection system for ITER

    SciTech Connect

    Marinucci, C.; Bottura, L. |; Pourrahimi, S.

    1995-03-01

    The purpose of this paper is to assess the expected response of conventional and non-conventional quench detection sensors proposed for the ITER coils, and to be tested in the QUELL experiment in SULTAN. The assessment is based on simulation of thermohydraulic transients in the ITER coils for various operating conditions, and a tentative definition of the transfer functions of each sensor concept. It is shown that, for the investigated conditions, the co-wound voltage taps are more accurate than hydraulic systems and conventional voltage balance methods. The additional complication associated with the insertion of taps in the conductor is well offset by the low sensitivity to external disturbances.

  8. Phylogenetic occurrence of coiled coil proteins: implications for tissue structure in metazoa via a coiled coil tissue matrix.

    PubMed

    Odgren, P R; Harvie, L W; Fey, E G

    1996-04-01

    We examined GenBank sequence files with a heptad repeat analysis program to assess the phylogenetic occurrence of coiled coil proteins, how heptad repeat domains are organized within them, and what structural/functional categories they comprise. Of 102,007 proteins analyzed, 5.95% (6,074) contained coiled coil domains; 1.26% (1,289) contained "extended" (> 75 amino acid) domains. While the frequency of proteins containing coiled coils was surprisingly constant among all biota, extended coiled coil proteins were fourfold more frequent in the animal kingdom and may reflect early events in the divergence of plants and animals. Structure/function categories of extended coils also revealed phylogenetic differences. In pathogens and parasites, many extended coiled coil proteins are external and bind host proteins. In animals, the majority of extended coiled coil proteins were identified as constituents of two protein categories: 1) myosins and motors; or 2) components of the nuclear matrix-intermediate filament scaffold. This scaffold, produced by sequential extraction of epithelial monolayers in situ, contains only 1-2% of the cell mass while accurately retaining morphological features of living epithelium and is greatly enriched in proteins with extensive, interrupted coiled coil forming domains. The increased occurrence of this type of protein in metazoa compared with plants or protists leads us to hypothesize a tissue-wide matrix of coiled coil interactions underlying metazoan differentiated cell and tissue structure.

  9. A periodic table of coiled-coil protein structures.

    PubMed

    Moutevelis, Efrosini; Woolfson, Derek N

    2009-01-23

    Coiled coils are protein structure domains with two or more alpha-helices packed together via interlacing of side chains known as knob-into-hole packing. We analysed and classified a large set of coiled-coil structures using a combination of automated and manual methods. This led to a systematic classification that we termed a "periodic table of coiled coils," which we have made available at http://coiledcoils.chm.bris.ac.uk/ccplus/search/periodic_table. In this table, coiled-coil assemblies are arranged in columns with increasing numbers of alpha-helices and in rows of increased complexity. The table provides a framework for understanding possibilities in and limits on coiled-coil structures and a basis for future prediction, engineering and design studies.

  10. Enhancing Induction Coil Reliability

    NASA Astrophysics Data System (ADS)

    Kreter, K.; Goldstein, R.; Yakey, C.; Nemkov, V.

    2014-12-01

    In induction hardening, thermal fatigue is one of the main copper failure modes of induction heat treating coils. There have been papers published that describe this failure mode and others that describe some good design practices. The variables previously identified as the sources of thermal fatigue include radiation from the part surface, frequency, current, concentrator losses, water pressure and coil wall thickness. However, there is very little quantitative data on the factors that influence thermal fatigue in induction coils is available in the public domain. By using finite element analysis software this study analyzes the effect of common design variables of inductor cooling, and quantifies the relative importance of these variables. A comprehensive case study for a single shot induction coil with Fluxtrol A concentrator applied is used for the analysis.

  11. Preconditioned iterations to calculate extreme eigenvalues

    SciTech Connect

    Brand, C.W.; Petrova, S.

    1994-12-31

    Common iterative algorithms to calculate a few extreme eigenvalues of a large, sparse matrix are Lanczos methods or power iterations. They converge at a rate proportional to the separation of the extreme eigenvalues from the rest of the spectrum. Appropriate preconditioning improves the separation of the eigenvalues. Davidson`s method and its generalizations exploit this fact. The authors examine a preconditioned iteration that resembles a truncated version of Davidson`s method with a different preconditioning strategy.

  12. Development of the ITER magnetic diagnostic set and specification.

    PubMed

    Vayakis, G; Arshad, S; Delhom, D; Encheva, A; Giacomin, T; Jones, L; Patel, K M; Pérez-Lasala, M; Portales, M; Prieto, D; Sartori, F; Simrock, S; Snipes, J A; Udintsev, V S; Watts, C; Winter, A; Zabeo, L

    2012-10-01

    ITER magnetic diagnostics are now in their detailed design and R&D phase. They have passed their conceptual design reviews and a working diagnostic specification has been prepared aimed at the ITER project requirements. This paper highlights specific design progress, in particular, for the in-vessel coils, steady state sensors, saddle loops and divertor sensors. Key changes in the measurement specifications, and a working concept of software and electronics are also outlined.

  13. Complex Coil Assisted Single Coil Embolization for Small Intracranial Aneurysm

    PubMed Central

    Yang, Tzu-Hsien; Ou, Chang-Hsien; Chan, Si-Wa; Chen, Tai-I; Yang, Chia-Jung; Chiang, Chia-Ming; Huang, Wen-Chien

    2013-01-01

    The purpose of the technical note is to introduce the complex coil assisted coil embolization method in the treatment of intracranial small aneurysm, in order to enhance the safety of the procedure. The first microcatheter was navigated into the aneurysm sac and the ultrasoft coil was used as the embolization coil. If the embolizations coil could not stay within the aneurysm sac smoothly, such as coil herniation into parent artery during the delivery process. The second microcatheter would be navigated to the aneurysm level in the parent artery. Another complex coil was delivered within the parent artery via the second microcatheter to provide the neck bridge effect in order to enhance the stability of embolization coil. Besides, the protection coil will not disturb the parent artery flow. While the embolization coil was put into the aneurysm sac smoothly under the help of complex protective coil, the protective coil was then withdrawn gently. We use the most magnified view, dual-plane approach simultaneously to observe the stability of embolization coil. The embolization coil would be detached without any evidence of coil motion or vibration. The new method could provide the physiological protective method, without leaving any protective device such as stent within the parent artery. PMID:24024075

  14. Testing Short Samples of ITER Conductors and Projection of Their Performance in ITER Magnets

    SciTech Connect

    Martovetsky, N N

    2007-08-20

    Qualification of the ITER conductor is absolutely necessary. Testing large scale conductors is expensive and time consuming. To test straight 3-4m long samples in a bore of a split solenoid is a relatively economical way in comparison with fabrication of a coil to be tested in a bore of a background field solenoid. However, testing short sample may give ambiguous results due to different constraints in current redistribution in the cable or other end effects which are not present in the large magnet. This paper discusses processes taking place in the ITER conductor, conditions when conductor performance could be distorted and possible signal processing to deduce behavior of ITER conductors in ITER magnets from the test data.

  15. Heterogeneous Superconducting Low-Noise Sensing Coils

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob; Penanen, Konstantin I.; Ho Eom, Byeong

    2008-01-01

    A heterogeneous material construction has been devised for sensing coils of superconducting quantum interference device (SQUID) magnetometers that are subject to a combination of requirements peculiar to some advanced applications, notably including low-field magnetic resonance imaging for medical diagnosis. The requirements in question are the following: The sensing coils must be large enough (in some cases having dimensions of as much as tens of centimeters) to afford adequate sensitivity; The sensing coils must be made electrically superconductive to eliminate Johnson noise (thermally induced noise proportional to electrical resistance); and Although the sensing coils must be cooled to below their superconducting- transition temperatures with sufficient cooling power to overcome moderate ambient radiative heat leakage, they must not be immersed in cryogenic liquid baths. For a given superconducting sensing coil, this combination of requirements can be satisfied by providing a sufficiently thermally conductive link between the coil and a cold source. However, the superconducting coil material is not suitable as such a link because electrically superconductive materials are typically poor thermal conductors. The heterogeneous material construction makes it possible to solve both the electrical- and thermal-conductivity problems. The basic idea is to construct the coil as a skeleton made of a highly thermally conductive material (typically, annealed copper), then coat the skeleton with an electrically superconductive alloy (typically, a lead-tin solder) [see figure]. In operation, the copper skeleton provides the required thermally conductive connection to the cold source, while the electrically superconductive coating material shields against Johnson noise that originates in the copper skeleton.

  16. Design and optimization of efficient magnetic coils for biomedical applications

    NASA Astrophysics Data System (ADS)

    Ram Rakhyani, Anil Kumar

    Magnetic fields are permeable to the biological tissues and can induce electric field in the conductive structures. Some medical devices take advantage of this ability to transfer energy from the source to the receiving site without direct contact. Prosthetic devices such as retinal implants use time-varying magnetic field to achieve wireless power transfer to the implanted magnetic coil. However, devices such as magnetic stimulators use the induction principle to create an electric field at the stimulation site. Efficiency of these devices is primarily dependent on the design of the magnetic coils. Therefore, in this work, we designed and validated efficient magnetic coils for wireless power transfer to implanted devices and magnetic stimulation of the peripheral nerves. Typical wireless power transfer (WPT) systems uses two-coil based design to achieve contactless power transfer to the implanted electronics. These systems achieve low power transfer efficiency (< 30%) and frequency bandwidth. Moreover, efficient wireless system requires high coupling and load variation tolerance during device operation. To design an electromagnetic safe WPT system, the power absorbed by the tissue and radiated field due to the proximal magnetic coils needs to be minimized. In this work, we proposed a multi-coil power transfer system which solves some of the current challenges. The proposed multi-coil WPT system achieves more than twice the power transfer efficiency, controllable voltage gain, wider frequency bandwidth, higher tolerance to coupling and load variations, lower absorbed power in the tissue and lower radiated field from the magnetic coil than a comparable two-coil system. In this work, we have developed analytic models of the multi-coil WPT system and validated the accuracy of the solutions using experiments. Magnetic coils play an important role in controlling the distribution of induced electric field inside the nerve during magnetic stimulation. In the past

  17. 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.

  18. A Case Study of Modern PLC and LabVIEW Controls: Power Supply Controls for the ORNL ITER ECH Test Stand

    SciTech Connect

    Barker, Alan M; Killough, Stephen M; Bigelow, Tim S; White, John A; Munro Jr, John K

    2011-01-01

    Power Supply Controls are being developed at Oak Ridge National Laboratory (ORNL) to test transmission line components of the Electron Cyclotron Heating (ECH) system, with a focus on gyrotrons and waveguides, in support of the International Thermonuclear Experimental Reactor (ITER). The control is performed by several Programmable Logic Controllers (PLC s) located near the different equipment. A technique of Supervisory Control and Data Acquisition (SCADA) is presented to monitor, control, and log actions of the PLC s on a PC through use of Allen Bradley s Remote I/O communication interface coupled with an Open Process Control/Object Linking and Embedding [OLE] for Process Control (OPC) Server/Client architecture. The OPC data is then linked to a National Instruments (NI) LabVIEW system for monitoring and control. Details of the architecture and insight into applicability to other systems are presented in the rest of this paper. Future integration with an EPICS (Experimental Physics Industrial Control System) based mini-CODAC (Control, Data Access and Communication) SCADA system is under consideration, and integration considerations will be briefly introduced.

  19. Hierarchical Cascades of Instability Govern the Mechanics of Coiled Coils: Helix Unfolding Precedes Coil Unzipping

    PubMed Central

    Hamed, Elham; Keten, Sinan

    2014-01-01

    Coiled coils are a fundamental emergent motif in proteins found in structural biomaterials, consisting of α-helical secondary structures wrapped in a supercoil. A fundamental question regarding the thermal and mechanical stability of coiled coils in extreme environments is the sequence of events leading to the disassembly of individual oligomers from the universal coiled-coil motifs. To shed light on this phenomenon, here we report atomistic simulations of a trimeric coiled coil in an explicit water solvent and investigate the mechanisms underlying helix unfolding and coil unzipping in the assembly. We employ advanced sampling techniques involving steered molecular dynamics and metadynamics simulations to obtain the free-energy landscapes of single-strand unfolding and unzipping in a three-stranded assembly. Our comparative analysis of the free-energy landscapes of instability pathways shows that coil unzipping is a sequential process involving multiple intermediates. At each intermediate state, one heptad repeat of the coiled coil first unfolds and then unzips due to the loss of contacts with the hydrophobic core. This observation suggests that helix unfolding facilitates the initiation of coiled-coil disassembly, which is confirmed by our 2D metadynamics simulations showing that unzipping of one strand requires less energy in the unfolded state compared with the folded state. Our results explain recent experimental findings and lay the groundwork for studying the hierarchical molecular mechanisms that underpin the thermomechanical stability/instability of coiled coils and similar protein assemblies. PMID:25028889

  20. Magnetostatic focal spot correction for x-ray tubes operating in strong magnetic fields using iterative optimization

    PubMed Central

    Lillaney, Prasheel; Shin, Mihye; Conolly, Steven M.; Fahrig, Rebecca

    2012-01-01

    Purpose: Combining x-ray fluoroscopy and MR imaging systems for guidance of interventional procedures has become more commonplace. By designing an x-ray tube that is immune to the magnetic fields outside of the MR bore, the two systems can be placed in close proximity to each other. A major obstacle to robust x-ray tube design is correcting for the effects of the magnetic fields on the x-ray tube focal spot. A potential solution is to design active shielding that locally cancels the magnetic fields near the focal spot. Methods: An iterative optimization algorithm is implemented to design resistive active shielding coils that will be placed outside the x-ray tube insert. The optimization procedure attempts to minimize the power consumption of the shielding coils while satisfying magnetic field homogeneity constraints. The algorithm is composed of a linear programming step and a nonlinear programming step that are interleaved with each other. The coil results are verified using a finite element space charge simulation of the electron beam inside the x-ray tube. To alleviate heating concerns an optimized coil solution is derived that includes a neodymium permanent magnet. Any demagnetization of the permanent magnet is calculated prior to solving for the optimized coils. The temperature dynamics of the coil solutions are calculated using a lumped parameter model, which is used to estimate operation times of the coils before temperature failure. Results: For a magnetic field strength of 88 mT, the algorithm solves for coils that consume 588 A/cm2. This specific coil geometry can operate for 15 min continuously before reaching temperature failure. By including a neodymium magnet in the design the current density drops to 337 A/cm2, which increases the operation time to 59 min. Space charge simulations verify that the coil designs are effective, but for oblique x-ray tube geometries there is still distortion of the focal spot shape along with deflections of approximately

  1. Magnetostatic focal spot correction for x-ray tubes operating in strong magnetic fields using iterative optimization

    SciTech Connect

    Lillaney, Prasheel; Shin, Mihye; Conolly, Steven M.; Fahrig, Rebecca

    2012-09-15

    Purpose: Combining x-ray fluoroscopy and MR imaging systems for guidance of interventional procedures has become more commonplace. By designing an x-ray tube that is immune to the magnetic fields outside of the MR bore, the two systems can be placed in close proximity to each other. A major obstacle to robust x-ray tube design is correcting for the effects of the magnetic fields on the x-ray tube focal spot. A potential solution is to design active shielding that locally cancels the magnetic fields near the focal spot. Methods: An iterative optimization algorithm is implemented to design resistive active shielding coils that will be placed outside the x-ray tube insert. The optimization procedure attempts to minimize the power consumption of the shielding coils while satisfying magnetic field homogeneity constraints. The algorithm is composed of a linear programming step and a nonlinear programming step that are interleaved with each other. The coil results are verified using a finite element space charge simulation of the electron beam inside the x-ray tube. To alleviate heating concerns an optimized coil solution is derived that includes a neodymium permanent magnet. Any demagnetization of the permanent magnet is calculated prior to solving for the optimized coils. The temperature dynamics of the coil solutions are calculated using a lumped parameter model, which is used to estimate operation times of the coils before temperature failure. Results: For a magnetic field strength of 88 mT, the algorithm solves for coils that consume 588 A/cm{sup 2}. This specific coil geometry can operate for 15 min continuously before reaching temperature failure. By including a neodymium magnet in the design the current density drops to 337 A/cm{sup 2}, which increases the operation time to 59 min. Space charge simulations verify that the coil designs are effective, but for oblique x-ray tube geometries there is still distortion of the focal spot shape along with deflections of

  2. Correction coil cable

    DOEpatents

    Wang, Sou-Tien

    1994-11-01

    A wire cable assembly (10, 310) adapted for the winding of electrical coils is taught. A primary intended use is for use in particle tube assemblies (532) for the superconducting super collider. The correction coil cables (10, 310) have wires (14, 314) collected in wire arrays (12, 312) with a center rib (16, 316) sandwiched therebetween to form a core assembly (18, 318 ). The core assembly (18, 318) is surrounded by an assembly housing (20, 320) having an inner spiral wrap (22, 322) and a counter wound outer spiral wrap (24, 324). An alternate embodiment (410) of the invention is rolled into a keystoned shape to improve radial alignment of the correction coil cable (410) on a particle tube (733) in a particle tube assembly (732).

  3. ITER safety challenges and opportunities

    SciTech Connect

    Piet, S.J.

    1991-01-01

    Results of the Conceptual Design Activity (CDA) for the International Thermonuclear Experimental Reactor (ITER) suggest challenges and opportunities. ITER is capable of meeting anticipated regulatory dose limits,'' but proof is difficult because of large radioactive inventories needing stringent radioactivity confinement. We need much research and development (R D) and design analysis to establish that ITER meets regulatory requirements. We have a further opportunity to do more to prove more of fusion's potential safety and environmental advantages and maximize the amount of ITER technology on the path toward fusion power plants. To fulfill these tasks, we need to overcome three programmatic challenges and three technical challenges. The first programmatic challenge is to fund a comprehensive safety and environmental ITER R D plan. Second is to strengthen safety and environment work and personnel in the international team. Third is to establish an external consultant group to advise the ITER Joint Team on designing ITER to meet safety requirements for siting by any of the Parties. The first of the three key technical challenges is plasma engineering -- burn control, plasma shutdown, disruptions, tritium burn fraction, and steady state operation. The second is the divertor, including tritium inventory, activation hazards, chemical reactions, and coolant disturbances. The third technical challenge is optimization of design requirements considering safety risk, technical risk, and cost. Some design requirements are now too strict; some are too lax. Fuel cycle design requirements are presently too strict, mandating inappropriate T separation from H and D. Heat sink requirements are presently too lax; they should be strengthened to ensure that maximum loss of coolant accident temperatures drop.

  4. US ITER Moving Forward

    ScienceCinema

    US ITER / ORNL

    2016-07-12

    US ITER Project Manager Ned Sauthoff, joined by Wayne Reiersen, Team Leader Magnet Systems, and Jan Berry, Team Leader Tokamak Cooling System, discuss the U.S.'s role in the ITER international collaboration.

  5. Imprinted Clay Coil Vessels

    ERIC Educational Resources Information Center

    Lohr, Tresa Rae

    2006-01-01

    The author teaches clay vessel construction in the fifth grade, and it is amazing what can be accomplished in one forty-five minute period when the expectations are clarified in the initial lesson. The author introduces clay coil vessels with a discussion of the sources of clay and how clay relates to fifth-grade science curriculum concepts such…

  6. Pulse Test of Coil Insulation

    NASA Technical Reports Server (NTRS)

    Kroy, Ralph E.

    1987-01-01

    Waveform of back-electromotive force reveals defects. Simple pulse test reveals defects in inductor coils. Devised for use on servovalve solenoid coils on Space Shuttle, test also applicable to transformer windings, chokes, relays, and the like.

  7. Improved Coil for Hydrogen Dissociators

    NASA Technical Reports Server (NTRS)

    Vessot, R.

    1984-01-01

    Flat coil has rigid printed circuit substrate. New coil structure minimizes RF electric field near glass walls of plasma vessel; therefore reduces direct electron bombardment of glass. Design lends itself well to high production and standardized dimensions.

  8. Wet Winding Improves Coil Encapsulation

    NASA Technical Reports Server (NTRS)

    Hill, A. J.

    1987-01-01

    Wet-winding process encapsulates electrical coils more uniformily than conventional processes. Process requires no vacuum pump and adapts easily to existing winding machines. Encapsulant applied to each layer of wire as soon as added to coil. Wet-winding process eliminates voids, giving more uniformly encapsulated coil.

  9. Design of printed circuit coils

    NASA Technical Reports Server (NTRS)

    Higgins, W. T.

    1969-01-01

    Spiral-like coil is printed with several extra turns which increase the realizable coil inductance. Included are shorting connections which not only short the extra turns, but also short out several turns of the main body. Coil tuning is accomplished by removing the shorts until the desired inductance is obtained.

  10. SU-F-18C-02: Evaluations of the Noise Power Spectrum of a CT Iterative Reconstruction Technique for Radiation Therapy

    SciTech Connect

    Dolly, S; Chen, H; Anastasio, M; Mutic, S; Li, H

    2014-06-15

    Purpose: To quantitatively assess the noise power spectrum (NPS) of the new, commercially released CT iterative reconstruction technique, iDose{sup 4} from Philips, to compare it with filtered back-projection techniques (FBP), and to provide clinical practice suggestions for radiation therapy. Methods: A uniform phantom was CT imaged with 120kVp tube potential over a range of mAs (250-3333). The image sets were reconstructed using two reconstruction algorithms (FBP and iDose{sup 4} with noise reduction levels 1, 3, and 6) and three reconstruction filters (standard B, smooth A, and sharp C), after which NPS variations were analyzed and compared on region of interest (ROI) sizes (16×16 to 128×128 pixels), ROI radii (0–65 mm), reconstruction algorithms, reconstruction filters, and mAs. Results: The NPS magnitude and shape depended considerably on ROI size and location for both reconstruction algorithms. Regional noise variance became more stationary as ROI size decreased, minimizing NPS artifacts. The optimal 32×32-pixel ROI size balanced the trade-off between stationary noise and adequate sampling. NPS artifacts were greatest at the center of reconstruction space and decreased with increasing ROI distance from the center. The optimal ROI position was located near the phantom's radial midpoint (∼40mm). For sharper filters, the NPS magnitude and the maximum magnitude frequency increased. Higher dose scans yielded lower NPS magnitudes for both reconstruction algorithms and all filters. Compared to FBP, the iDose{sup 4} algorithm reduced the NPS magnitude while preferentially reducing noise at mid-range spatial frequencies, altering noise texture. This reduction was more significant with increasing iDose{sup 4} noise reduction level. Conclusion: Compared to pixel standard deviation, NPS has greater clinical potential for task-based image quality assessment, describing both the magnitude and spatial frequency characteristics of image noise. While iDose{sup 4

  11. Considerations in the design and optimization of coiled coil structures.

    PubMed

    Mason, Jody M; Müller, Kristian M; Arndt, Katja M

    2007-01-01

    Coiled coil motifs are, despite their apparent simplicity, highly specific, and play a significant role in the understanding of tertiary structure and its formation. The most commonly observed of the coiled coils, the parallel dimeric, is yet to be fully characterized for this structural class in general. Nonetheless, strict rules have emerged for the necessity of specific types of amino acids at specific positions. In this chapter, we discuss this system in light of existing coiled coil structures and in applying rules to coiled coils that are to be designed or optimized. Understanding and expanding on these rules is crucial in using these motifs, which play key roles in virtually every cellular process, to act as drug-delivery agents by sequestering other proteins that are not behaving natively or that have been upregulated (for example, by binding to coiled coil domains implicated in oncogenesis). The roles of the a and d "hydrophobic" core positions and the e and g "electrostatic" edge positions in directing oligomerization and pairing specificity are discussed. Also discussed is the role of these positions in concert with the b, c, and f positions in maintaining alpha-helical propensity, helix solubility, and dimer stability. PMID:17041258

  12. Considerations in the design and optimization of coiled coil structures.

    PubMed

    Mason, Jody M; Müller, Kristian M; Arndt, Katja M

    2007-01-01

    Coiled coil motifs are, despite their apparent simplicity, highly specific, and play a significant role in the understanding of tertiary structure and its formation. The most commonly observed of the coiled coils, the parallel dimeric, is yet to be fully characterized for this structural class in general. Nonetheless, strict rules have emerged for the necessity of specific types of amino acids at specific positions. In this chapter, we discuss this system in light of existing coiled coil structures and in applying rules to coiled coils that are to be designed or optimized. Understanding and expanding on these rules is crucial in using these motifs, which play key roles in virtually every cellular process, to act as drug-delivery agents by sequestering other proteins that are not behaving natively or that have been upregulated (for example, by binding to coiled coil domains implicated in oncogenesis). The roles of the a and d "hydrophobic" core positions and the e and g "electrostatic" edge positions in directing oligomerization and pairing specificity are discussed. Also discussed is the role of these positions in concert with the b, c, and f positions in maintaining alpha-helical propensity, helix solubility, and dimer stability.

  13. ECRH System For ITER

    SciTech Connect

    Darbos, C.; Henderson, M.; Gandini, F.; Albajar, F.; Bomcelli, T.; Heidinger, R.; Saibene, G.; Chavan, R.; Goodman, T.; Hogge, J. P.; Sauter, O.; Denisov, G.; Farina, D.; Kajiwara, K.; Kasugai, A.; Kobayashi, N.; Oda, Y.; Ramponi, G.

    2009-11-26

    A 26 MW Electron Cyclotron Heating and Current Drive (EC H and CD) system is to be installed for ITER. The main objectives are to provide, start-up assist, central H and CD and control of MHD activity. These are achieved by a combination of two types of launchers, one located in an equatorial port and the second type in four upper ports. The physics applications are partitioned between the two launchers, based on the deposition location and driven current profiles. The equatorial launcher (EL) will access from the plasma axis to mid radius with a relatively broad profile useful for central heating and current drive applications, while the upper launchers (ULs) will access roughly the outer half of the plasma radius with a very narrow peaked profile for the control of the Neoclassical Tearing Modes (NTM) and sawtooth oscillations. The EC power can be switched between launchers on a time scale as needed by the immediate physics requirements. A revision of all injection angles of all launchers is under consideration for increased EC physics capabilities while relaxing the engineering constraints of both the EL and ULs. A series of design reviews are being planned with the five parties (EU, IN, JA, RF, US) procuring the EC system, the EC community and ITER Organization (IO). The review meetings qualify the design and provide an environment for enhancing performances while reducing costs, simplifying interfaces, predicting technology upgrades and commercial availability. In parallel, the test programs for critical components are being supported by IO and performed by the Domestic Agencies (DAs) for minimizing risks. The wide participation of the DAs provides a broad representation from the EC community, with the aim of collecting all expertise in guiding the EC system optimization. Still a strong relationship between IO and the DA is essential for optimizing the design of the EC system and for the installation and commissioning of all ex-vessel components when several

  14. Formulation for a practical implementation of electromagnetic induction coils optimized using stream functions

    NASA Astrophysics Data System (ADS)

    Reed, Mark A.; Scott, Waymond R.

    2016-05-01

    Continuous-wave (CW) electromagnetic induction (EMI) systems used for subsurface sensing typically employ separate transmit and receive coils placed in close proximity. The closeness of the coils is desirable for both packaging and object pinpointing; however, the coils must have as little mutual coupling as possible. Otherwise, the signal from the transmit coil will couple into the receive coil, making target detection difficult or impossible. Additionally, mineralized soil can be a significant problem when attempting to detect small amounts of metal because the soil effectively couples the transmit and receive coils. Optimization of wire coils to improve their performance is difficult but can be made possible through a stream-function representation and the use of partially convex forms. Examples of such methods have been presented previously, but these methods did not account for certain practical issues with coil implementation. In this paper, the power constraint introduced into the optimization routine is modified so that it does not penalize areas of high current. It does this by representing the coils as plates carrying surface currents and adjusting the sheet resistance to be inversely proportional to the current, which is a good approximation for a wire-wound coil. Example coils are then optimized for minimum mutual coupling, maximum sensitivity, and minimum soil response at a given height with both the earlier, constant sheet resistance and the new representation. The two sets of coils are compared both to each other and other common coil types to show the method's viability.

  15. AC Loss Measurements on a 2G YBCO Coil

    SciTech Connect

    Rey, Christopher M; Duckworth, Robert C; Schwenterly, S W

    2011-01-01

    The Oak Ridge National Laboratory (ORNL) is collaborating with Waukesha Electric Systems (WES) to continue development of HTS power transformers. For compatibility with the existing power grid, a commercially viable HTS transformer will have to operate at high voltages in the range of 138 kV and above, and will have to withstand 550-kV impulse voltages as well. Second-generation (2G) YBCO coated conductors will be required for an economically-competitive design. In order to adequately size the refrigeration system for these transformers, the ac loss of these HTS coils must be characterized. Electrical AC loss measurements were conducted on a prototype high voltage (HV) coil with co-wound stainless steel at 60 Hz in a liquid nitrogen bath using a lock-in amplifier technique. The prototype HV coil consisted of 26 continuous (without splice) single pancake coils concentrically centered on a stainless steel former. For ac loss measurement purposes, voltage tap pairs were soldered across each set of two single pancake coils so that a total of 13 separate voltage measurements could be made across the entire length of the coil. AC loss measurements were taken as a function of ac excitation current. Results show that the loss is primarily concentrated at the ends of the coil where the operating fraction of critical current is the highest and show a distinct difference in current scaling of the losses between low current and high current regimes.

  16. ITER test programme

    NASA Astrophysics Data System (ADS)

    Abdou, M.; Baker, C.; Casini, G.

    1991-07-01

    The International Thermonuclear Experimental Reactor (ITER) was designed to operate in two phases. The first phase, which lasts for 6 years, is devoted to machine checkout and physics testing. The second phase lasts for 8 years and is devoted primarily to technology testing. This report describes the technology test program development for ITER, the ancillary equipment outside the torus necessary to support the test modules, the international collaboration aspects of conducting the test program on ITER, the requirements on the machine major parameters and the R and D program required to develop the test modules for testing in ITER.

  17. Design of Tokamak ELM Coil Support in High Nuclear Heat Environment

    NASA Astrophysics Data System (ADS)

    Zhang, Shanwen; Song, Yuntao; Wang, Zhongwei; Ji, Xiang; Daly, E.; Kalish, M.; Lu, Su; Du, Shuangsong; Liu, Xufeng; Feng, Changle; Yang, Hong; Wang, Songke

    2014-03-01

    In Tokomak, the support of the ELM coil, which is close to the plasma and subject to high radiation level, high temperature and high magnetic field, is used to transport and bear the thermal load due to thermal expansion and the alternating electromagnetic force generated by high magnetic field and AC current in the coil. According to the feature of ITER ELM coil, the mechanical performance of rigid and flexible supports under different high nuclear heat levels is studied. Results show that flexible supports have more excellent performance in high nuclear heat condition than rigid supports. Concerning thermal and electromagnetic (EM) loads, optimized results further prove that flexible supports have better mechanical performance than rigid ones. Through these studies, reasonable support design can be provided for the ELM coils or similar coils in Tokamak based on the nuclear heat level.

  18. Study of Nb3Sn strands and cables for Fermilab's common coil dipole models

    NASA Astrophysics Data System (ADS)

    Barzi, E.; Ambrosio, G.; Fratini, M.; Bauer, P.; Scanlan, R. M.; Yamada, R.; Zlobin, A. V.

    2002-05-01

    Fermilab is developing 10-12 T superconducting dipole magnets for future accelerators based on Nb3Sn conductor. Within the High Field Magnet Project, a common coil design was chosen for magnet R&D using the react & wind approach. Based on cable studies in which a variety of designs were tried and tested using inexpensive ITER strands, a 41-strand cable was used for a racetrack coil, whereas a 60-strand cable was preferred for the common coil model. Multifilamentary Nb3Sn strands 0.7 mm in diameter to be respectively used in the racetrack coil and the common coil model were purchased from OST (Modified Jelly Roll technology) and IGC (Internal Tin technology). They are herein characterized by Ic, n-value, residual resistivity ratio, and magnetization. Results of cabling and bending degradation are also presented.

  19. 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.

  20. Parametric design of tri-axial nested Helmholtz coils

    SciTech Connect

    Abbott, Jake J.

    2015-05-15

    This paper provides an optimal parametric design for tri-axial nested Helmholtz coils, which are used to generate a uniform magnetic field with controllable magnitude and direction. Circular and square coils, both with square cross section, are considered. Practical considerations such as wire selection, wire-wrapping efficiency, wire bending radius, choice of power supply, and inductance and time response are included. Using the equations provided, a designer can quickly create an optimal set of custom coils to generate a specified field magnitude in the uniform-field region while maintaining specified accessibility to the central workspace. An example case study is included.

  1. Resistive toroidal-field coils for tokamak reactors

    SciTech Connect

    Kalnavarns, J.; Jassby, D.L.

    1980-11-01

    This paper analyzes the optimization of the geometry of resistive TF coils of rectangular bore for tokamak fusion test reactors and practical neutron generators. In examining the trade-offs between geometric parameters and magnetic field for reactors giving a specified neutron wall loading, either the resistive power loss or the lifetime coil cost can be minimized. Aspects of cooling, magnetic stress, and construction are addressed for several reference designs. Bending moment distributions in closed form have been derived for rectangular coils on the basis of the theory of rigid frames. Candidate methods of fabrication and of implementing demountable joints are summarized.

  2. Programmable Iterative Optical Image And Data Processing

    NASA Technical Reports Server (NTRS)

    Jackson, Deborah J.

    1995-01-01

    Proposed method of iterative optical image and data processing overcomes limitations imposed by loss of optical power after repeated passes through many optical elements - especially, beam splitters. Involves selective, timed combination of optical wavefront phase conjugation and amplification to regenerate images in real time to compensate for losses in optical iteration loops; timing such that amplification turned on to regenerate desired image, then turned off so as not to regenerate other, undesired images or spurious light propagating through loops from unwanted reflections.

  3. Bi-2223 HTS winding in toroidal configuration for SMES coil

    NASA Astrophysics Data System (ADS)

    Kondratowicz-Kucewicz, B.; Janowski, T.; Kozak, S.; Kozak, J.; Wojtasiewicz, G.; Majka, M.

    2010-06-01

    Energy can be stored in the magnetic field of a coil. Superconducting Magnetic Energy Storage (SMES) is very promising as a power storage system for load levelling or power stabilizer. However, the strong electromagnetic force caused by high magnetic field and large coil current is a problem in SMES systems. A toroidal configuration would have a much less extensive external magnetic field and electromagnetic forces in winding. The paper describes the design of HTS winding for SMES coil in modular toroid configuration consist of seven Bi-2223 double-pancakes as well as numerical analysis of SMES magnet model using FLUX 3D package. As the results of analysis the paper presents the optimal coil configuration and the parameters such as radius of toroidal magnet, energy stored in magnet and magnetic field distribution.

  4. Low-Cost Superconducting Wire for Wind Generators: High Performance, Low Cost Superconducting Wires and Coils for High Power Wind Generators

    SciTech Connect

    2012-01-01

    REACT Project: The University of Houston will develop a low-cost, high-current superconducting wire that could be used in high-power wind generators. Superconducting wire currently transports 600 times more electric current than a similarly sized copper wire, but is significantly more expensive. The University of Houston’s innovation is based on engineering nanoscale defects in the superconducting film. This could quadruple the current relative to today’s superconducting wires, supporting the same amount of current using 25% of the material. This would make wind generators lighter, more powerful and more efficient. The design could result in a several-fold reduction in wire costs and enable their commercial viability of high-power wind generators for use in offshore applications.

  5. Iteration, Not Induction

    ERIC Educational Resources Information Center

    Dobbs, David E.

    2009-01-01

    The main purpose of this note is to present and justify proof via iteration as an intuitive, creative and empowering method that is often available and preferable as an alternative to proofs via either mathematical induction or the well-ordering principle. The method of iteration depends only on the fact that any strictly decreasing sequence of…

  6. Triple Halo Coil: Development and Comparison with Other TMS Coils

    NASA Astrophysics Data System (ADS)

    Rastogi, Priyam; Hadimani, Ravi; Jiles, David

    Transcranial Magnetic Stimulation (TMS) is a non-invasive stimulation technique that can be used for the treatment of various neurological disorders such as Parkinson's Disease, PTSD, TBI and anxiety by regulating synaptic activity. TMS is FDA approved for the treatment of major depressive disorder. There is a critical need to develop deep TMS coils that can stimulate deeper regions of the brain without excessively stimulating the cortex in order to provide an alternative to surgical methods. We have developed a novel multi-coil configuration called ``Triple Halo Coil'' (THC) that can stimulate deep brain regions. Investigation of induced electric and magnetic field in these regions have been achieved by computer modelling. Comparison of the results due to THC configuration have been conducted with other TMS coils such as ``Halo Coil'', circular coil and ``Figure of Eight'' coil. There was an improvement of more than 15 times in the strength of magnetic field, induced by THC configuration at 10 cm below the vertex of the head when compared with the ``Figure of Eight'' coil alone. Carver Charitable Trust.

  7. Coiled coils ensure the physiological ectodomain shedding of collagen XVII.

    PubMed

    Nishie, Wataru; Jackow, Joanna; Hofmann, Silke C; Franzke, Claus-Werner; Bruckner-Tuderman, Leena

    2012-08-24

    α-Helical coiled coils, frequent protein oligomerization motifs, are commonly observed in vital proteins. Here, using collagen XVII as an example, we provide evidence for a novel function of coiled coils in the regulation of ectodomain shedding. Transmembrane collagen XVII, an epithelial cell surface receptor, mediates dermal-epidermal adhesion in the skin, and its dysfunction is linked to human skin blistering diseases. The ectodomain of this collagen is constitutively shed from the cell surface by proteinases of a disintegrin and metalloprotease family; however, the mechanisms regulating shedding remain elusive. Here, we used site-specific mutagenesis to target the coiled-coil heptad repeats within the juxtamembranous, extracellular noncollagenous 16th A (NC16A) domain of collagen XVII. This resulted in a substantial increase of ectodomain shedding, which was not mediated by disintegrin and metalloproteases. Instead, conformational changes induced by the mutation(s) unmasked a furin recognition sequence that was used for cleavage. This study shows that apart from their functions in protein oligomerization, coiled coils can also act as regulators of ectodomain shedding depending on the biological context.

  8. Adaptive self-calibrating iterative GRAPPA reconstruction.

    PubMed

    Park, Suhyung; Park, Jaeseok

    2012-06-01

    Parallel magnetic resonance imaging in k-space such as generalized auto-calibrating partially parallel acquisition exploits spatial correlation among neighboring signals over multiple coils in calibration to estimate missing signals in reconstruction. It is often challenging to achieve accurate calibration information due to data corruption with noises and spatially varying correlation. The purpose of this work is to address these problems simultaneously by developing a new, adaptive iterative generalized auto-calibrating partially parallel acquisition with dynamic self-calibration. With increasing iterations, under a framework of the Kalman filter spatial correlation is estimated dynamically updating calibration signals in a measurement model and using fixed-point state transition in a process model while missing signals outside the step-varying calibration region are reconstructed, leading to adaptive self-calibration and reconstruction. Noise statistic is incorporated in the Kalman filter models, yielding coil-weighted de-noising in reconstruction. Numerical and in vivo studies are performed, demonstrating that the proposed method yields highly accurate calibration and thus reduces artifacts and noises even at high acceleration. PMID:21994010

  9. Adaptive self-calibrating iterative GRAPPA reconstruction.

    PubMed

    Park, Suhyung; Park, Jaeseok

    2012-06-01

    Parallel magnetic resonance imaging in k-space such as generalized auto-calibrating partially parallel acquisition exploits spatial correlation among neighboring signals over multiple coils in calibration to estimate missing signals in reconstruction. It is often challenging to achieve accurate calibration information due to data corruption with noises and spatially varying correlation. The purpose of this work is to address these problems simultaneously by developing a new, adaptive iterative generalized auto-calibrating partially parallel acquisition with dynamic self-calibration. With increasing iterations, under a framework of the Kalman filter spatial correlation is estimated dynamically updating calibration signals in a measurement model and using fixed-point state transition in a process model while missing signals outside the step-varying calibration region are reconstructed, leading to adaptive self-calibration and reconstruction. Noise statistic is incorporated in the Kalman filter models, yielding coil-weighted de-noising in reconstruction. Numerical and in vivo studies are performed, demonstrating that the proposed method yields highly accurate calibration and thus reduces artifacts and noises even at high acceleration.

  10. STELLOPT Modeling of the 3D Diagnostic Response in ITER

    SciTech Connect

    Lazerson, Samuel A

    2013-05-07

    The ITER three dimensional diagnostic response to an n=3 resonant magnetic perturbation is modeled using the STELLOPT code. The in-vessel coils apply a resonant magnetic perturbation (RMP) fi eld which generates a 4 cm edge displacement from axisymmetry as modeled by the VMEC 3D equilibrium code. Forward modeling of flux loop and magnetic probe response with the DIAGNO code indicates up to 20 % changes in measured plasma signals. Simulated LIDAR measurements of electron temperature indicate 2 cm shifts on the low field side of the plasma. This suggests that the ITER diagnostic will be able to diagnose the 3D structure of the equilibria.

  11. New progress of ITER-PF strand production in WST

    NASA Astrophysics Data System (ADS)

    Li, J. F.; Liu, W. T.; Yan, L. X.; H, J.; Gao, H. X.; Liu, J. W.; Du, S. J.; Liu, X. H.; Feng, Y.; Zhang, P. X.; Liu, S.; Li, H. W.; Niu, E. W.

    2014-05-01

    ITER Poloidal Field (PF) systems consist of 6 independent coils with different dimensions and require NbTi superconductor and copper strands. Western Superconducting Technologies Co.,Ltd.(WST) will supply PF2-5 NbTi strand for ITER, and over 14,000 km of NbTi strands have been produced in the past two years. Main performance of NbTi strands, including critical current, n value, wire diameter, Cu/non-Cu ratio, hysteresis loss and RRR are reported and analysed in this paper.

  12. Note: High turn density magnetic coils with improved low pressure water cooling for use in atom optics

    NASA Astrophysics Data System (ADS)

    McKay Parry, Nicholas; Baker, Mark; Neely, Tyler; Carey, Thomas; Bell, Thomas; Rubinsztein-Dunlop, Halina

    2014-08-01

    We describe a magnetic coil design utilizing concentrically wound electro-magnetic insulating (EMI) foil (25.4 μm Kapton backing and 127 μm thick layers). The magnetic coils are easily configurable for different coil sizes, while providing large surfaces for low-pressure (0.12 bar) water cooling. The coils have turn densities of ˜5 mm-1 and achieve a maximum of 377 G at 2.1 kW driving power, measured at a distance 37.9 mm from the axial center of the coil. The coils achieve a steady-state temperature increase of 36.7°C/kW.

  13. 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.

  14. Replaceable Sleeve Protects Welder Coil

    NASA Technical Reports Server (NTRS)

    Baker, W. L.; Simpson, C., E.

    1983-01-01

    New replaceable carbon insert for deflection coil in electron-beam welder promises to decrease maintenance costs. Inserts made from materials other than carbon (not yet tried) are less expensive, thus reducing costs even further. With carbon insert, deflection coils last longer and are easier to maintain.

  15. 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.

  16. Magnetically Damped Furnace Bitter Magnet Coil 1

    NASA Technical Reports Server (NTRS)

    Bird, M. D.

    1997-01-01

    A magnet has been built by the National High Magnetic Field Laboratory for NASA on a cost reimbursement contract. The magnet is intended to demonstrate the technology and feasibility of building a magnet for space based crystal growth. A Bitter magnet (named after Francis Bitter, its inventor) was built consisting of four split coils electrically in series and hydraulically in parallel. The coils are housed in a steel vessel to reduce the fringe field and provide some on-axis field enhancement. The steel was nickel plated and Teflon coated to minimize interaction with the water cooling system. The magnet provides 0.14 T in a 184 mm bore with 3 kW of power.

  17. Solving coiled-coil protein structures

    DOE PAGES

    Dauter, Zbigniew

    2015-02-26

    With the availability of more than 100,000 entries stored in the Protein Data Bank (PDB) that can be used as search models, molecular replacement (MR) is currently the most popular method of solving crystal structures of macromolecules. Significant methodological efforts have been directed in recent years towards making this approach more powerful and practical. This resulted in the creation of several computer programs, highly automated and user friendly, that are able to successfully solve many structures even by researchers who, although interested in structures of biomolecules, are not very experienced in crystallography.

  18. The Coil Method in Contemporary Ceramics

    ERIC Educational Resources Information Center

    Nigrosh, Leon I.

    1976-01-01

    For centuries coil building has been the primary method of making pottery the world over. Many classrooms still reflect this preference for symmetrical coil building. Describes coil building and what forms can be made from it. (Author/RK)

  19. On the safety of ITER accelerators.

    PubMed

    Li, Ge

    2013-01-01

    Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate -1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER.

  20. Open half-volume quadrature transverse electromagnetic coil for high-field magnetic resonance imaging.

    PubMed

    Peshkovsky, A S; Kennan, R P; Fabry, M E; Avdievich, N I

    2005-04-01

    A half-volume quadrature head transverse electromagnetic (TEM) coil has been constructed for 4 T imaging applications. This coil produces a sufficiently large homogeneous B(1) field region for the use as a volume coil. It provides superior transmission efficiency, resulting in significantly lower power deposition, as well as greater sensitivity and improved patient comfort and accessibility compared with conventional full-volume coils. Additionally, this coil suppresses the RF penetration artifact that distorts the RF magnetic field profile and alters the intensity in high-field images recorded with linear surface and volume coils. These advantages make it possible to apply this device as an efficient transmit/receive coil for high-field imaging with a restricted field of view.

  1. Coiled-coil intermediate filament stutter instability and molecular unfolding.

    PubMed

    Arslan, Melis; Qin, Zhao; Buehler, Markus J

    2011-05-01

    Intermediate filaments (IFs) are the key components of cytoskeleton in eukaryotic cells and are critical for cell mechanics. The building block of IFs is a coiled-coil alpha-helical dimer, consisting of several domains that include linkers and other structural discontinuities. One of the discontinuities in the dimer's coiled-coil region is the so-called 'stutter' region. The stutter is a region where a variation of the amino acid sequence pattern from other parts of the alpha-helical domains of the protein is found. It was suggested in earlier works that due to this sequence variation, the perfect coiled-coil arrangement ceases to exist. Here, we show using explicit water molecular dynamics and well-tempered metadynamics that for the coil2 domain of vimentin IFs the stutter is more stable in a non-alpha-helical, unfolded state. This causes a local structural disturbance in the alpha helix, which has a global effect on the nanomechanics of the structure. Our analysis suggests that the stutter features an enhanced tendency to unfolding even under the absence of external forces, implying a much greater structural instability than previously assumed. As a result it features a smaller local bending stiffness than other segments and presents a seed for the initiation of molecular bending and unfolding at large deformation. PMID:21516532

  2. Electrical and Quench Performance of the First MICE Coupling Coil

    DOE PAGES

    Tartaglia, M. A.; Carcagno, R.; Makulski, A.; Nogiec, Jerzy; Orris, D.; Pilipenko, R.; Sylvester, C.; Caspi, S.; Pan, H.; Prestemon, S.; et al

    2014-11-10

    The first MICE Coupling Coil has been tested in a conduction-cooled environment in the new Solenoid Test Facility at Fermilab. We present an overview of the power and quench protection scheme, and report on the electrical and quench performance results obtained during cold power tests of the magnet.

  3. ITER Plasma Control System Development

    NASA Astrophysics Data System (ADS)

    Snipes, Joseph; ITER PCS Design Team

    2015-11-01

    The development of the ITER Plasma Control System (PCS) continues with the preliminary design phase for 1st plasma and early plasma operation in H/He up to Ip = 15 MA in L-mode. The design is being developed through a contract between the ITER Organization and a consortium of plasma control experts from EU and US fusion laboratories, which is expected to be completed in time for a design review at the end of 2016. This design phase concentrates on breakdown including early ECH power and magnetic control of the poloidal field null, plasma current, shape, and position. Basic kinetic control of the heating (ECH, ICH, NBI) and fueling systems is also included. Disruption prediction, mitigation, and maintaining stable operation are also included because of the high magnetic and kinetic stored energy present already for early plasma operation. Support functions for error field topology and equilibrium reconstruction are also required. All of the control functions also must be integrated into an architecture that will be capable of the required complexity of all ITER scenarios. A database is also being developed to collect and manage PCS functional requirements from operational scenarios that were defined in the Conceptual Design with links to proposed event handling strategies and control algorithms for initial basic control functions. A brief status of the PCS development will be presented together with a proposed schedule for design phases up to DT operation.

  4. 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.

  5. Perl Modules for Constructing Iterators

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt

    2009-01-01

    The Iterator Perl Module provides a general-purpose framework for constructing iterator objects within Perl, and a standard API for interacting with those objects. Iterators are an object-oriented design pattern where a description of a series of values is used in a constructor. Subsequent queries can request values in that series. These Perl modules build on the standard Iterator framework and provide iterators for some other types of values. Iterator::DateTime constructs iterators from DateTime objects or Date::Parse descriptions and ICal/RFC 2445 style re-currence descriptions. It supports a variety of input parameters, including a start to the sequence, an end to the sequence, an Ical/RFC 2445 recurrence describing the frequency of the values in the series, and a format description that can refine the presentation manner of the DateTime. Iterator::String constructs iterators from string representations. This module is useful in contexts where the API consists of supplying a string and getting back an iterator where the specific iteration desired is opaque to the caller. It is of particular value to the Iterator::Hash module which provides nested iterations. Iterator::Hash constructs iterators from Perl hashes that can include multiple iterators. The constructed iterators will return all the permutations of the iterations of the hash by nested iteration of embedded iterators. A hash simply includes a set of keys mapped to values. It is a very common data structure used throughout Perl programming. The Iterator:: Hash module allows a hash to include strings defining iterators (parsed and dispatched with Iterator::String) that are used to construct an overall series of hash values.

  6. The role of heating and current drive in ITER

    SciTech Connect

    Nevins, W.M.; Haney, S.

    1993-10-18

    This report discusses and summarize the role of heating and non-inductive current drive in ITER as: (1) ITER must have heating power sufficient for ignition. (2) The heating system must be capable of current drive. (3) Steady-state operation is an ``ultimate goal.`` It is recognized that additional heating and current drive power (beyond what is initially installed on ITER) may be required. (4) The ``Ultimate goal of steady-state operation`` means steady-state with Q{sub CD} {ge} 5. Unlike the ``Terms of Reference`` for the ITER CDA, the ``ITER Technical Objectives and Approaches`` for the EDA sets no goal for the neutron wall load during steady-state operation. (5) In addition to bulk current drive, the ITER heating and current drive system should be used for current profile control and for burn control.

  7. Diagnostics for ITER

    SciTech Connect

    Donne, A. J. H.; Hellermann, M. G. von; Barnsley, R.

    2008-10-22

    After an introduction into the specific challenges in the field of diagnostics for ITER (specifically high level of nuclear radiation, long pulses, high fluxes of particles to plasma facing components, need for reliability and robustness), an overview will be given of the spectroscopic diagnostics foreseen for ITER. The paper will describe both active neutral-beam based diagnostics as well as passive spectroscopic diagnostics operating in the visible, ultra-violet and x-ray spectral regions.

  8. ITER convertible blanket evaluation

    SciTech Connect

    Wong, C.P.C.; Cheng, E.

    1995-09-01

    Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate.

  9. The evolution and structure prediction of coiled coils across all genomes.

    PubMed

    Rackham, Owen J L; Madera, Martin; Armstrong, Craig T; Vincent, Thomas L; Woolfson, Derek N; Gough, Julian

    2010-10-29

    Coiled coils are α-helical interactions found in many natural proteins. Various sequence-based coiled-coil predictors are available, but key issues remain: oligomeric state and protein-protein interface prediction and extension to all genomes. We present SpiriCoil (http://supfam.org/SUPERFAMILY/spiricoil), which is based on a novel approach to the coiled-coil prediction problem for coiled coils that fall into known superfamilies: hundreds of hidden Markov models representing coiled-coil-containing domain families. Using whole domains gives the advantage that sequences flanking the coiled coils help. SpiriCoil performs at least as well as existing methods at detecting coiled coils and significantly advances the state of the art for oligomer state prediction. SpiriCoil has been run on over 16 million sequences, including all completely sequenced genomes (more than 1200), and a resulting Web interface supplies data downloads, alignments, scores, oligomeric state classifications, three-dimensional homology models and visualisation. This has allowed, for the first time, a genomewide analysis of coiled-coil evolution. We found that coiled coils have arisen independently de novo well over a hundred times, and these are observed in 16 different oligomeric states. Coiled coils in almost all oligomeric states were present in the last universal common ancestor of life. The vast majority of occasions that individual coiled coils have arisen de novo were before the last universal common ancestor of life; we do, however, observe scattered instances throughout subsequent evolutionary history, mostly in the formation of the eukaryote superkingdom. Coiled coils do not change their oligomeric state over evolution and did not evolve from the rearrangement of existing helices in proteins; coiled coils were forged in unison with the fold of the whole protein.

  10. Improved Sensing Coils for SQUIDs

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin; Hahn, Inseob; Eom, Byeong Ho

    2007-01-01

    An improvement in the design and fabrication of sensing coils of superconducting quantum interference device (SQUID) magnetometers has been proposed to increase sensitivity. It has been estimated that, in some cases, it would be possible to increase sensitivity by about half or to reduce measurement time correspondingly. The pertinent aspects of the problems of design and fabrication can be summarized as follows: In general, to increase the sensitivity of a SQUID magnetometer, it is necessary to maximize the magnetic flux enclosed by the sensing coil while minimizing the self-inductance of this coil. It is often beneficial to fabricate the coil from a thicker wire to reduce its self-inductance. Moreover, to optimize the design of the coil with respect to sensitivity, it may be necessary to shape the wire to other than a commonly available circular or square cross-section. On the other hand, it is not practical to use thicker superconducting wire for the entire superconducting circuit, especially if the design of a specific device requires a persistent-current loop enclosing a remotely placed SQUID sensor. It may be possible to bond a thicker sensing-coil wire to thinner superconducting wires leading to a SQUID sensor, but it could be difficult to ensure reliable superconducting connections, especially if the bonded wires are made of different materials. The main idea is to mold the sensing coil in place, to more nearly optimum cross sectional shape, instead of making the coil by winding standard pre-fabricated wire. For this purpose, a thin superconducting wire loop that is an essential part of the SQUID magnetometer would be encapsulated in a form that would serve as a mold. A low-melting-temperature superconducting metal (e.g., indium, tin, or a lead/tin alloy) would be melted into the form, which would be sized and shaped to impart the required cross section to the coil thus formed.

  11. Characteristics of aerodynamic sound sources generated by coiled wires in a uniform air-flow

    NASA Astrophysics Data System (ADS)

    Matsumoto, H.; Nishida, K.; Saitoh, K.

    2003-11-01

    This study deals experimentally with aerodynamic sounds generated by coiled wires in a uniform air-flow. The coiled wire is a model of the hair dryer's heater. In the experiment, the effects of the coil diameter D, wire diameter d and coil spacing s of the coiled wire on the aerodynamic sound have been clarified. The results of frequency analyses of the aerodynamic sounds show that an Aeolian sound is generated by the coiled wire, when s/d is larger than 1. Also the peak frequencies of Aeolian sounds generated by the coiled wires are higher than the ones generated by a straight cylinder having the same diameter d. To clarify the characteristics of the aerodynamic sound sources, the directivity of the aerodynamic sound generated by the coiled wire has been examined, and the coherent function between the velocity fluctuation around the coiled wire and the aerodynamic sound has been calculated. Moreover, the band overall value of coherent output power between the sound and the velocity fluctuations has been calculated. This method has clarified the sound source region of the Aeolian sound generated by the coiled wire. These results show that the Aeolian sound is generated by the arc part of the coiled wire, which is located in the upstream side of the air-flow.

  12. Infrared amide I' band of the coiled coil.

    PubMed

    Reisdorf, W C; Krimm, S

    1996-02-01

    The Fourier transform infrared (FTIR) spectra of several coiled-coil proteins have been shown to possess unusual features in the amide I' region. Band maxima occur in the vicinity of 1630 cm-1, with component bands at higher frequency. This is well below the observed band at 1650 cm-1 found in standard alpha-helical polypeptides such as poly-L-alanine. Normal mode calculations on models of the coiled-coil structure have been performed to investigate this issue. We find that the observed band profile can be reproduced with very small random variation on the phi, psi of tropomyosin. We believe that the shift to lower frequency is due to additional hydrogen bonding of the solvent accessible backbone CO groups to water.

  13. Laminated magnet field coil sheath

    DOEpatents

    Skaritka, John R.

    1987-12-01

    a method for manufacturing a magnet cable trim coil in a sheath assembly for use in a cryogenic particle accelerator. A precisely positioned pattern of trim coil turns is bonded to a flexible substrate sheath that is capable of withstanding cryogenic operating conditions. In the method of the invention the flexible sheath, with the trim coil pattern precisely positioned thereon, is accurately positioned at a precise location relative to a bore tube assembly of an accelerator and is then bonded to the bore tube with a tape suitable for cryogenic application. The resultant assembly can be readily handled and installed within an iron magnet yoke assembly of a suitable cryogenic particle accelerator.

  14. Laminated magnet field coil sheath

    DOEpatents

    Skaritka, J.R.

    1987-05-15

    A method for manufacturing a magnetic cable trim coil in a sheath assembly for use in a cryogenic particle accelerator. A precisely positioned pattern of trim coil turns is bonded to a flexible substrate sheath that is capable of withstanding cryogenic operating conditions. In the method of the invention the flexible substrate sheath, with the trim coil pattern precisely location relative to a bore tube assembly of an accelerator and is then bonded to the bore tube with a tape suitable for cryogenic application. The resultant assembly can be readily handled and installed within an iron magnet yoke assembly of a suitable cryogenic particle accelerator. 1 fig.

  15. Coiling of a viscous filament

    NASA Astrophysics Data System (ADS)

    Samuel, A. D. T.; Ryu, W. S.; Mahadevan, L.

    1997-11-01

    A classic demonstration of fluid buckling is a daily occurence at the breakfast table, where a continuous stream of viscous fluid (honey) is often poured onto a flat surface (toast) from a sufficient height. The thin fluid filament quickly settles into a steady state; near the surface it bends into a helical shape while simultaneously rotating about the vertical and is laid out in a regular coil. This behavior is reminiscent of the coiling of a falling flexible rope. We derive a simple scaling law that predicts the coiling frequency in terms of the filament radius and the flow rate. We also verify this scaling law with the results of experiments.

  16. Growth factor identity is encoded by discrete coiled coil rotamers in the EGFR juxtamembrane region

    PubMed Central

    Doerner, Amy; Scheck, Rebecca; Schepartz, Alanna

    2015-01-01

    Summary Binding of the growth factor TGF-α to the EGFR extracellular domain is encoded through the formation of a unique anti-parallel coiled coil within the juxtamembrane segment. This new coiled coil is an ‘inside-out’ version of the coiled coil formed in the presence of EGF. A third, intermediary coiled coil interface is formed in the juxtamembrane segment when EGFR is stimulated with betacellulin. The seven growth factors that activate EGFR in mammalian systems (EGF, TGF-α, epigen, epiregulin, betacellulin, heparin-binding EGF, and amphiregulin) fall into distinct categories in which the structure of the coiled coil induced within the juxtamembrane segment correlates with cell state. The observation that coiled coil state tracks with the downstream signaling profiles for each ligand provides evidence for growth factor functional selectivity by EGFR. Encoding growth factor identity in alternative coiled coil rotamers provides a simple and elegant method for communicating chemical information across the plasma membrane. PMID:26091170

  17. Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game?

    PubMed Central

    Winter, Lukas; Dieringer, Matthias A.; Els, Antje; Oezerdem, Celal; Rieger, Jan; Kuehne, Andre; Cassara, Antonino M.; Pfeiffer, Harald; Wetterling, Friedrich; Niendorf, Thoralf

    2016-01-01

    Introduction The purpose of this study was to demonstrate the feasibility and efficiency of cardiac MR at 3 Tesla using local four-channel RF coil transmission and benchmark it against large volume body RF coil excitation. Methods Electromagnetic field simulations are conducted to detail RF power deposition, transmission field uniformity and efficiency for local and body RF coil transmission. For both excitation regimes transmission field maps are acquired in a human torso phantom. For each transmission regime flip angle distributions and blood-myocardium contrast are examined in a volunteer study of 12 subjects. The feasibility of the local transceiver RF coil array for cardiac chamber quantification at 3 Tesla is demonstrated. Results Our simulations and experiments demonstrate that cardiac MR at 3 Tesla using four-channel surface RF coil transmission is competitive versus current clinical CMR practice of large volume body RF coil transmission. The efficiency advantage of the 4TX/4RX setup facilitates shorter repetition times governed by local SAR limits versus body RF coil transmission at whole-body SAR limit. No statistically significant difference was found for cardiac chamber quantification derived with body RF coil versus four-channel surface RF coil transmission. Our simulation also show that the body RF coil exceeds local SAR limits by a factor of ~2 when driven at maximum applicable input power to reach the whole-body SAR limit. Conclusion Pursuing local surface RF coil arrays for transmission in cardiac MR is a conceptually appealing alternative to body RF coil transmission, especially for patients with implants. PMID:27598923

  18. High-resolution structures of a heterochiral coiled coil

    PubMed Central

    Mortenson, David E.; Steinkruger, Jay D.; Kreitler, Dale F.; Perroni, Dominic V.; Sorenson, Gregory P.; Huang, Lijun; Mittal, Ritesh; Yun, Hyun Gi; Travis, Benjamin R.; Mahanthappa, Mahesh K.; Forest, Katrina T.; Gellman, Samuel H.

    2015-01-01

    Interactions between polypeptide chains containing amino acid residues with opposite absolute configurations have long been a source of interest and speculation, but there is very little structural information for such heterochiral associations. The need to address this lacuna has grown in recent years because of increasing interest in the use of peptides generated from d amino acids (d peptides) as specific ligands for natural proteins, e.g., to inhibit deleterious protein–protein interactions. Coiled–coil interactions, between or among α-helices, represent the most common tertiary and quaternary packing motif in proteins. Heterochiral coiled–coil interactions were predicted over 50 years ago by Crick, and limited experimental data obtained in solution suggest that such interactions can indeed occur. To address the dearth of atomic-level structural characterization of heterochiral helix pairings, we report two independent crystal structures that elucidate coiled-coil packing between l- and d-peptide helices. Both structures resulted from racemic crystallization of a peptide corresponding to the transmembrane segment of the influenza M2 protein. Networks of canonical knobs-into-holes side-chain packing interactions are observed at each helical interface. However, the underlying patterns for these heterochiral coiled coils seem to deviate from the heptad sequence repeat that is characteristic of most homochiral analogs, with an apparent preference for a hendecad repeat pattern. PMID:26460035

  19. ASTROMAG coil cooling study

    NASA Technical Reports Server (NTRS)

    Maytal, Ben-Zion; Vansciver, Steven W.

    1990-01-01

    ASTROMAG is a planned particle astrophysics magnetic facility. Basically it is a large magnetic spectrometer outside the Earth's atmosphere for an extended period of time in orbit on a space station. A definition team summarized its scientific objectives assumably related to fundamental questions of astrophysics, cosmology, and elementary particle physics. Since magnetic induction of about 7 Tesla is desired, it is planned to be a superconducting magnet cooled to liquid helium 2 temperatures. The general structure of ASTROMAG is based on: (1) two superconducting magnetic coils, (2) dewar of liquid helium 2 to provide cooling capability for the magnets; (3) instrumentation, matter-anti matter spectrometer (MAS) and cosmic ray isotope spectrometer (CRIS); and (4) interfaces to the shuttle and space station. Many configurations of the superconducting magnets and the dewar were proposed and evaluated, since those are the heart of the ASTROMAG. Baseline of the magnet configuration and cryostat as presented in the phase A study and the one kept in mind while doing the present study are presented. ASTROMAG's development schedule reflects the plan of launching to the space station in 1995.

  20. ITER Central Solenoid Alternate Pre-Compression Structure Concept and Analysis

    SciTech Connect

    Litherland, P Steve; Freudenberg, Kevin D

    2009-01-01

    The ITER Central Solenoid (CS) is comprised of six independent coils held together by a pre-compression support structure. This structure must provide enough preload to maintain sufficient coil-to-coil contact throughout the current pulse. End of burn (EOB) represents one extreme time-point when the currents in the CS3 coils oppose those of CS1 & CS2. The present baseline design uses nine tie plate pairs located on the coil ID and OD to achieve this pre-compression. While this is an efficient structural approach, the outer tie plates limit access to the coil OD and result in very tight tolerances over the 12.75 m tall toroidal field (TF) coil bore. An alternative pre-compression structure has been developed by the US ITER Project Office, which addresses both of these issues using only internal tension members. This allows clear access to the outer CS surface for plumbing and current feeders, and more reasonable OD tolerances. In addition, the Tension Rod pre-compression structure utilizes existing technology (such as hydraulic tensioner or Superbolt{reg_sign}), which streamlines initial preloading and subsequent adjustments. Structural and transient electromagnetic FEA of the tension rod concept demonstrates that the stresses, displacements, and preliminary Eddy current heat loads are within allowable limits. Fabrication estimates demonstrate no additional cost of the tension rods compared to the tie plates.

  1. Experiments and modeling on FTU tokamak for EC assisted plasma start-up studies in ITER-like configuration

    NASA Astrophysics Data System (ADS)

    Granucci, G.; Garavaglia, S.; Ricci, D.; Artaserse, G.; Belli, F.; Bin, W.; Calabrò, G.; Cavinato, M.; Farina, D.; Figini, L.; Moro, A.; Ramogida, G.; Sozzi, C.; Tudisco, O.; FTU Team

    2015-09-01

    The intrinsic limited toroidal electric field (0.3 V m-1) in devices with superconducting poloidal coils (ITER, JT-60SA) requires additional heating, like electron cyclotron (EC) waves, to initiate plasma and to sustain it during the burn-through phase. The FTU tokamak has contributed to studying the perspective of EC assisted plasma breakdown. Afterward, a new experimental and modeling activity addressing the study of assisted plasma start-up in a configuration close to the ITER one (magnetic field, oblique injection, and polarization) has been performed and is presented here. These experiments have been supported by a 0D code, BKD0, developed to model the plasma start-up and linked to a beam tracing code computing, in a consistent way, EC absorption. The FTU results demonstrate the role of polarization conversion at the inner wall reflection. Dedicated experiments also showed the capability of EC power to sustain plasma start-up in the presence of strong error field (12 mT), with a null outside the vacuum vessel. The BKD0 code, applied to FTU data, has been used to determine the operational window of sustained breakdown as a function of toroidal electric field and neutral pressure. Experimental results in agreement with the BKD0 simulations support the use of the code to predict start-up in future tokamaks, like ITER and JT60SA.

  2. ITER Experts' meeting on density limits

    SciTech Connect

    Borrass, K.; Igitkhanov, Y.L.; Uckan, N.A.

    1989-12-01

    The necessity of achieving a prescribed wall load or fusion power essentially determines the plasma pressure in a device like ITER. The range of operation densities and temperatures compatible with this condition is constrained by the problems of power exhaust and the disruptive density limit. The maximum allowable heat loads on the divertor plates and the maximum allowable sheath edge temperature practically impose a lower limit on the operating densities, whereas the disruptive density limit imposes an upper limit. For most of the density limit scalings proposed in the past an overlap of the two constraints or at best a very narrow accessible density range is predicted for ITER. Improved understanding of the underlying mechanisms is therefore a crucial issue in order to provide a more reliable basis for extrapolation to ITER and to identify possible ways of alleviating the problem.

  3. A new moving-coil microelectrode puller.

    PubMed

    Ensor, D R

    1979-03-01

    This paper describes an improved electrode puller for the manufacture of glass microelectrodes or micropipettes. The instrument resembles a conventional horizontal two-stage, solenoid-powered electrode puller but the pull is now developed by a light moving-coil and a fixed permanent magnet, using the principle of the moving-coil loudspeaker. In a conventional puller the force is generated by a solenoid with a massive moving-iron core. In this new puller the moving-coil solenoid responds much more rapidly to changing currents because of its greatly reduced inductance, and a substantial reduction in mass to 25 g, gives more acceleration from a comparable force. The sudden discharge of a capacitor bank through the coil accelerates the glass quickly during the last stage of the pull. This rapid acceleration is of importance in the formation of good electrodes with fine tips. For the prototype, an electronic control unit was constructed which allows the parameters necessary for the manufacture of electrodes to be set and regulated accurately and repeatedly, so that series of electrodes of constant shapes can be made. The length of the electrode shank may be predetermined over a wide range and tip diameters down to 0.08 micron have already been measured. The angle of the taper that supports the tip may be varied from less than 1 to over 6 degrees. The mechanical design of the instrument is comparatively simple, as it has only one moving part, while the relative complexity of the electronic control section should not present any manufacturing difficulties. Although this puller has been used mainly to make single-barrel fine electrodes from borosilicate glass, it is adaptable for other purposes. The extent of the control over the shape of the shank of the electrode renders it particularly suitable for the manufacture of composite, ion-sensitive electrodes. PMID:544958

  4. Overview on Experiments On ITER-like Antenna On JET And ICRF Antenna Design For ITER

    SciTech Connect

    Nightingale, M. P. S.; Blackman, T.; Edwards, D.; Fanthome, J.; Graham, M.; Hamlyn-Harris, C.; Hancock, D.; Jacquet, P.; Mayoral, M.-L.; Monakhov, I.; Nicholls, K.; Stork, D.; Whitehurst, A.; Wilson, D.; Wooldridge, E.

    2009-11-26

    Following an overview of the ITER Ion Cyclotron Resonance Frequency (ICRF) system, the JET ITER-like antenna (ILA) will be described. The ILA was designed to test the following ITER issues: (a) reliable operation at power densities of order 8 MW/m{sup 2} at voltages up to 45 kV using a close-packed array of straps; (b) powering through ELMs using an internal (in-vacuum) conjugate-T junction; (c) protection from arcing in a conjugate-T configuration, using both existing and novel systems; and (d) resilience to disruption forces. ITER-relevant results have been achieved: operation at high coupled power density; control of the antenna matching elements in the presence of high inter-strap coupling, use of four conjugate-T systems (as would be used in ITER, should a conjugate-T approach be used); operation with RF voltages on the antenna structures up to 42 kV; achievement of ELM tolerance with a conjugate-T configuration by operating at 3{omega} real impedance at the conjugate-T point; and validation of arc detection systems on conjugate-T configurations in ELMy H-mode plasmas. The impact of these results on the predicted performance and design of the ITER antenna will be reviewed. In particular, the implications of the RF coupling measured on JET will be discussed.

  5. Performance analysis of the Nb-Ti conductor qualification samples for the ITER project

    NASA Astrophysics Data System (ADS)

    Breschi, M.; Carati, D.; Bessette, D.; Devred, A.; Romano, G.; Vostner, A.; Zhou, C.

    2015-11-01

    The ITER machine will require approximately 275 tons of Nb-Ti strands that will be used in poloidal field (PF) coils, correction coils (CC) and feeder busbars. The performance of all these conductors for the ITER machine is qualified by a short full-size sample (4 m) current sharing temperature (T cs) test in the SULTAN facility at CRPP in Villigen, Switzerland, at the design operating current and peak field. Three ITER domestic agencies participated in PF conductor fabrication (China, the European Union, Russia) while the conductors for feeder busbars and correction coils are entirely produced by the Chinese domestic agency. Each conductor type was qualified by the ITER International Organization after reaching T cs values in excess of ITER specifications. This qualification enabled the launch of procurement and industrial production of the Nb-Ti cable-in-conduit conductors in each domestic agency. In this paper, we summarize the performance of the qualified Nb-Ti samples of the ITER Project, comparing strand performance with conductor performance. The details of the test results will be discussed in terms of dc performance, ac losses and minimum quench energies of each conductor type.

  6. Zero-angle helical coil

    NASA Technical Reports Server (NTRS)

    Troendle, J. A.

    1976-01-01

    Device is constructed of bimetallic stock material formed into segments of small diameters and fastened together by metal strips. Coil is useful in various types of actuators, such as temperature controls.

  7. Adjustable Induction-Heating Coil

    NASA Technical Reports Server (NTRS)

    Ellis, Rod; Bartolotta, Paul

    1990-01-01

    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  8. Novel aspects of plasma control in ITER

    NASA Astrophysics Data System (ADS)

    Humphreys, D.; Ambrosino, G.; de Vries, P.; Felici, F.; Kim, S. H.; Jackson, G.; Kallenbach, A.; Kolemen, E.; Lister, J.; Moreau, D.; Pironti, A.; Raupp, G.; Sauter, O.; Schuster, E.; Snipes, J.; Treutterer, W.; Walker, M.; Welander, A.; Winter, A.; Zabeo, L.

    2015-02-01

    ITER plasma control design solutions and performance requirements are strongly driven by its nuclear mission, aggressive commissioning constraints, and limited number of operational discharges. In addition, high plasma energy content, heat fluxes, neutron fluxes, and very long pulse operation place novel demands on control performance in many areas ranging from plasma boundary and divertor regulation to plasma kinetics and stability control. Both commissioning and experimental operations schedules provide limited time for tuning of control algorithms relative to operating devices. Although many aspects of the control solutions required by ITER have been well-demonstrated in present devices and even designed satisfactorily for ITER application, many elements unique to ITER including various crucial integration issues are presently under development. We describe selected novel aspects of plasma control in ITER, identifying unique parts of the control problem and highlighting some key areas of research remaining. Novel control areas described include control physics understanding (e.g., current profile regulation, tearing mode (TM) suppression), control mathematics (e.g., algorithmic and simulation approaches to high confidence robust performance), and integration solutions (e.g., methods for management of highly subscribed control resources). We identify unique aspects of the ITER TM suppression scheme, which will pulse gyrotrons to drive current within a magnetic island, and turn the drive off following suppression in order to minimize use of auxiliary power and maximize fusion gain. The potential role of active current profile control and approaches to design in ITER are discussed. Issues and approaches to fault handling algorithms are described, along with novel aspects of actuator sharing in ITER.

  9. Novel aspects of plasma control in ITER

    SciTech Connect

    Humphreys, D.; Jackson, G.; Walker, M.; Welander, A.; Ambrosino, G.; Pironti, A.; Felici, F.; Kallenbach, A.; Raupp, G.; Treutterer, W.; Kolemen, E.; Lister, J.; Sauter, O.; Moreau, D.; Schuster, E.

    2015-02-15

    ITER plasma control design solutions and performance requirements are strongly driven by its nuclear mission, aggressive commissioning constraints, and limited number of operational discharges. In addition, high plasma energy content, heat fluxes, neutron fluxes, and very long pulse operation place novel demands on control performance in many areas ranging from plasma boundary and divertor regulation to plasma kinetics and stability control. Both commissioning and experimental operations schedules provide limited time for tuning of control algorithms relative to operating devices. Although many aspects of the control solutions required by ITER have been well-demonstrated in present devices and even designed satisfactorily for ITER application, many elements unique to ITER including various crucial integration issues are presently under development. We describe selected novel aspects of plasma control in ITER, identifying unique parts of the control problem and highlighting some key areas of research remaining. Novel control areas described include control physics understanding (e.g., current profile regulation, tearing mode (TM) suppression), control mathematics (e.g., algorithmic and simulation approaches to high confidence robust performance), and integration solutions (e.g., methods for management of highly subscribed control resources). We identify unique aspects of the ITER TM suppression scheme, which will pulse gyrotrons to drive current within a magnetic island, and turn the drive off following suppression in order to minimize use of auxiliary power and maximize fusion gain. The potential role of active current profile control and approaches to design in ITER are discussed. Issues and approaches to fault handling algorithms are described, along with novel aspects of actuator sharing in ITER.

  10. RHIC D0 INSERTION DIPOLE DESIGN ITERATIONS DURING PRODUCTION.

    SciTech Connect

    SCHMALZLE,J.; ANERELLA,M.; GANETIS,G.; GHOSH,A.; GUPTA,R.; JAIN,A.; KAHN,S.; MORGAN,G.; MURATORE,J.; SAMPSON,W.; WANDERER,P.; WILLEN,E.

    1997-05-12

    Iterations to the cross section of the Relativistic Heavy Ion Collider (RHIC) D0 Insertion Dipole magnets were made during the production. This was included as part of the production plan because no R&D or pre-production magnets were built prior to the start of production. The first magnet produced had the desired coil pre-stress and low field harmonics in the body of the magnet and is therefore being used in the RHIC Machine. On the first eight magnets, iterations were carried out to minimize the iron saturation and to compensate for the end harmonics. This paper will discuss the details of the iterations made, the obstacles encountered, and the results obtained. Also included will be a brief summary of the magnet design and performance.

  11. The Role of Filtration in Maintaining Clean Heat Exchanger Coils

    SciTech Connect

    Li Yang; James E. Braun; Eckhard A. Groll

    2004-06-30

    eat transfer coefficient. In most cases, the EER was reduced with fouling primarily due to increased fan power. However, the changes in EER were relatively small, in the range of 1%-9% (10%). For most cases, equipment having low efficiency filters had higher EER after fouling than equipment with high efficiency filters, because the high efficiency filter caused significantly higher pressure drops than the low efficiency filters. The extra filter pressure drop outweighed the reduced coil pressure drop after fouling. The impact of fan efficiency curves was also investigated in the study. The energy penalty associated with high efficiency filters was reduced considerably with higher efficiency fans. There is an energy penalty associated with the use of high efficiency filtration. However, the primary reason for selecting high efficiency filters for a particular application would be improved air quality. For HX8L, the quantity of dust passing through the coil with a MERV4 filter was approximately 30 times the dust passing the coil with a MERV14 filter. Without an upstream filter, the quantity of dust passing through the coil was approximately 60 times the value for a MERV14 filter.

  12. Nylon screws make inexpensive coil forms

    NASA Technical Reports Server (NTRS)

    Aucoin, G.; Rosenthal, C.

    1978-01-01

    Standard nylon screws act as coil form copper wire laid down in spiral thread. Completed coil may be bonded to printed-circuit board. However, it is impossible to tune coil by adjusting spacing between windings, technique sometimes used with air-core coils.

  13. Thermal Stability Analysis for Superconducting Coupling Coil in MICE

    SciTech Connect

    Wu, Hong; Wang, Li; Pan, Heng; Guo, XingLong; Green, M.A.

    2010-06-28

    The superconducting coupling coil to be used in the Muon Ionization Cooling Experiment (MICE) with inner radius of 750 mm, length of 285 mm and thickness of 110.4 mm will be cooled by a pair of 1.5 W at 4.2 K cryo-coolers. When the coupling coil is powered to 210 A, it will produce about 7.3 T peak magnetic field at the conductor and it will have a stored energy of 13 MJ. A key issue for safe operation of the coupling coil is the thermal stability of the coil during a charge and discharge. The magnet and its cooling system are designed for a rapid discharge where the magnet is to be discharged in 5400 seconds. The numerical simulation for the thermal stability of the MICE coupling coil has been done using ANSYS. The analysis results show that the superconducting coupling coil has a good stability and can be charged and discharged safely.

  14. Microtearing Instability In The ITER Pedestal

    SciTech Connect

    Wong, K. L.; Mikkelsen, D. R.; Rewoldt, G. M.; Budny, R.

    2010-12-01

    Unstable microtearing modes are discovered by the GS2 gyrokinetic siimulation code, in the pedestal region of a simulated ITER H-mode plasma with approximately 400 WM DT fusion power. Existing nonlinear theory indicates that these instabilities should produce stochastic magnetic fields and broaden the pedestal. The resulted electron thermal conductivity is estimated and the implications of these findings are discussed.

  15. Robust iterative methods

    SciTech Connect

    Saadd, Y.

    1994-12-31

    In spite of the tremendous progress achieved in recent years in the general area of iterative solution techniques, there are still a few obstacles to the acceptance of iterative methods in a number of applications. These applications give rise to very indefinite or highly ill-conditioned non Hermitian matrices. Trying to solve these systems with the simple-minded standard preconditioned Krylov subspace methods can be a frustrating experience. With the mathematical and physical models becoming more sophisticated, the typical linear systems which we encounter today are far more difficult to solve than those of just a few years ago. This trend is likely to accentuate. This workshop will discuss (1) these applications and the types of problems that they give rise to; and (2) recent progress in solving these problems with iterative methods. The workshop will end with a hopefully stimulating panel discussion with the speakers.

  16. The physics role of ITER

    SciTech Connect

    Rutherford, P.H.

    1997-04-01

    Experimental research on the International Thermonuclear Experimental Reactor (ITER) will go far beyond what is possible on present-day tokamaks to address new and challenging issues in the physics of reactor-like plasmas. First and foremost, experiments in ITER will explore the physics issues of burning plasmas--plasmas that are dominantly self-heated by alpha-particles created by the fusion reactions themselves. Such issues will include (i) new plasma-physical effects introduced by the presence within the plasma of an intense population of energetic alpha particles; (ii) the physics of magnetic confinement for a burning plasma, which will involve a complex interplay of transport, stability and an internal self-generated heat source; and (iii) the physics of very-long-pulse/steady-state burning plasmas, in which much of the plasma current is also self-generated and which will require effective control of plasma purity and plasma-wall interactions. Achieving and sustaining burning plasma regimes in a tokamak necessarily requires plasmas that are larger than those in present experiments and have higher energy content and power flow, as well as much longer pulse length. Accordingly, the experimental program on ITER will embrace the study of issues of plasma physics and plasma-materials interactions that are specific to a reactor-scale fusion experiment. Such issues will include (i) confinement physics for a tokamak in which, for the first time, the core-plasma and the edge-plasma are simultaneously in a reactor-like regime; (ii) phenomena arising during plasma transients, including so-called disruptions, in regimes of high plasma current and thermal energy; and (iii) physics of a radiative divertor designed for handling high power flow for long pulses, including novel plasma and atomic-physics effects as well as materials science of surfaces subject to intense plasma interaction. Experiments on ITER will be conducted by researchers in control rooms situated at major

  17. Rescheduling with iterative repair

    NASA Technical Reports Server (NTRS)

    Zweben, Monte; Davis, Eugene; Daun, Brian; Deale, Michael

    1992-01-01

    This paper presents a new approach to rescheduling called constraint-based iterative repair. This approach gives our system the ability to satisfy domain constraints, address optimization concerns, minimize perturbation to the original schedule, produce modified schedules, quickly, and exhibits 'anytime' behavior. The system begins with an initial, flawed schedule and then iteratively repairs constraint violations until a conflict-free schedule is produced. In an empirical demonstration, we vary the importance of minimizing perturbation and report how fast the system is able to resolve conflicts in a given time bound. We also show the anytime characteristics of the system. These experiments were performed within the domain of Space Shuttle ground processing.

  18. Iterative method for generating correlated binary sequences

    NASA Astrophysics Data System (ADS)

    Usatenko, O. V.; Melnik, S. S.; Apostolov, S. S.; Makarov, N. M.; Krokhin, A. A.

    2014-11-01

    We propose an efficient iterative method for generating random correlated binary sequences with a prescribed correlation function. The method is based on consecutive linear modulations of an initially uncorrelated sequence into a correlated one. Each step of modulation increases the correlations until the desired level has been reached. The robustness and efficiency of the proposed algorithm are tested by generating sequences with inverse power-law correlations. The substantial increase in the strength of correlation in the iterative method with respect to single-step filtering generation is shown for all studied correlation functions. Our results can be used for design of disordered superlattices, waveguides, and surfaces with selective transport properties.

  19. Free-boundary Full-pressure Island Healing in a Stellarator: Coil-healing

    SciTech Connect

    S.R.Hudson; A. Reiman; D. Strickler; A. Brooks; D.A. Monticello; and S.P. Hirshman

    2002-05-07

    The lack of axisymmetry in stellarators guarantees that in general magnetic islands and chaotic magnetic field lines will exist. As particle transport is strongly tied to the magnetic field lines, magnetic islands and chaotic field lines result in poor plasma confinement. For stellarators to be feasible candidates for fusion power stations it is essential that, to a good approximation, the magnetic field lines lie on nested flux-surfaces, and the suppression of magnetic islands is a critical issue for stellarator coil design, particularly for small aspect ratio devices. A procedure for modifying stellarator coil designs to eliminate magnetic islands in free-boundary full-pressure magnetohydrodynamic equilibria is presented. Islands may be removed from coil-plasma free-boundary equilibria by making small changes to the coil geometry and also by variation of trim coil currents. A plasma and coil design relevant to the National Compact Stellarator Experiment is used to illustrate the technique.

  20. A Switched-Mode Breast Coil for 7 T MRI Using Forced-Current Excitation

    PubMed Central

    Bosshard, John C.; Rispoli, Joseph V.; Dimitrov, Ivan E.; Cheshkov, Sergey; McDougall, Mary Preston; Malloy, Craig; Wright, Steven M.

    2015-01-01

    In high-field magnetic resonance imaging, the radio frequency wavelength within the human body is comparable to anatomical dimensions, resulting in B1 inhomogeneity and nonuniform sensitivity patterns. Thus, this relatively short wavelength presents engineering challenges for RF coil design. In this study, a bilateral breast coil for 1H imaging at 7 T was designed and constructed using forced-current excitation. By forcing equal current through the coil elements, we reduce the effects of coupling between the elements to simplify tuning and to ensure a uniform field across both breasts. To combine the benefits of the higher power efficiency of a unilateral coil with the bilateral coverage of a bilateral coil, a switching circuit was implemented to allow the coil to be reconfigured for imaging the left, right, or both breasts. PMID:25706501

  1. Analysis of Thermal-Hydraulic Gravity/ Buoyancy Effects in the Testing of the ITER Poloidal Field Full Size Joint Sample (PF-FSJS)

    SciTech Connect

    Zanino, R.; Savoldi Richard, L.; Bruzzone, P.; Ciazynski, D.; Nicollet, S.

    2004-06-23

    The PF-FSJS is a full-size joint sample, based on the NbTi dual-channel cable-in-conduit conductor (CICC) design currently foreseen for the International Thermonuclear Experimental Reactor (ITER) Poloidal Field coil system. It was tested during the summer of 2002 in the Sultan facility of CRPP at a background peak magnetic field of typically 6 T. It includes about 3 m of two jointed conductor sections, using different strands but with identical layout. The sample was cooled by supercritical helium at nominal 4.5-5.0 K and 0.9-1.0 MPa, in forced convection from the top to the bottom of the vertical configuration. A pulsed coil was used to test AC losses in the two legs resulting, above a certain input power threshold, in bundle helium backflow from the heated region. Here we study the thermal-hydraulics of the phenomenon with the M and M code, with particular emphasis on the effects of buoyancy on the helium dynamics, as well as on the thermal-hydraulic coupling between the wrapped bundles of strands in the annular cable region and the central cooling channel. Both issues are ITER relevant, as they affect the more general question of the heat removal capability of the helium in this type of conductors.

  2. Designed coiled coils promote folding of a recombinant bacterial collagen.

    PubMed

    Yoshizumi, Ayumi; Fletcher, Jordan M; Yu, Zhuoxin; Persikov, Anton V; Bartlett, Gail J; Boyle, Aimee L; Vincent, Thomas L; Woolfson, Derek N; Brodsky, Barbara

    2011-05-20

    Collagen triple helices fold slowly and inefficiently, often requiring adjacent globular domains to assist this process. In the Streptococcus pyogenes collagen-like protein Scl2, a V domain predicted to be largely α-helical, occurs N-terminal to the collagen triple helix (CL). Here, we replace this natural trimerization domain with a de novo designed, hyperstable, parallel, three-stranded, α-helical coiled coil (CC), either at the N terminus (CC-CL) or the C terminus (CL-CC) of the collagen domain. CD spectra of the constructs are consistent with additivity of independently and fully folded CC and CL domains, and the proteins retain their distinctive thermal stabilities, CL at ∼37 °C and CC at >90 °C. Heating the hybrid proteins to 50 °C unfolds CL, leaving CC intact, and upon cooling, the rate of CL refolding is somewhat faster for CL-CC than for CC-CL. A construct with coiled coils on both ends, CC-CL-CC, retains the ∼37 °C thermal stability for CL but shows less triple helix at low temperature and less denaturation at 50 °C. Most strikingly however, in CC-CL-CC, the CL refolds slower than in either CC-CL or CL-CC by almost two orders of magnitude. We propose that a single CC promotes folding of the CL domain via nucleation and in-register growth from one end, whereas initiation and growth from both ends in CC-CL-CC results in mismatched registers that frustrate folding. Bioinformatics analysis of natural collagens lends support to this because, where present, there is generally only one coiled-coil domain close to the triple helix, and it is nearly always N-terminal to the collagen repeat.

  3. Designed coiled coils promote folding of a recombinant bacterial collagen.

    PubMed

    Yoshizumi, Ayumi; Fletcher, Jordan M; Yu, Zhuoxin; Persikov, Anton V; Bartlett, Gail J; Boyle, Aimee L; Vincent, Thomas L; Woolfson, Derek N; Brodsky, Barbara

    2011-05-20

    Collagen triple helices fold slowly and inefficiently, often requiring adjacent globular domains to assist this process. In the Streptococcus pyogenes collagen-like protein Scl2, a V domain predicted to be largely α-helical, occurs N-terminal to the collagen triple helix (CL). Here, we replace this natural trimerization domain with a de novo designed, hyperstable, parallel, three-stranded, α-helical coiled coil (CC), either at the N terminus (CC-CL) or the C terminus (CL-CC) of the collagen domain. CD spectra of the constructs are consistent with additivity of independently and fully folded CC and CL domains, and the proteins retain their distinctive thermal stabilities, CL at ∼37 °C and CC at >90 °C. Heating the hybrid proteins to 50 °C unfolds CL, leaving CC intact, and upon cooling, the rate of CL refolding is somewhat faster for CL-CC than for CC-CL. A construct with coiled coils on both ends, CC-CL-CC, retains the ∼37 °C thermal stability for CL but shows less triple helix at low temperature and less denaturation at 50 °C. Most strikingly however, in CC-CL-CC, the CL refolds slower than in either CC-CL or CL-CC by almost two orders of magnitude. We propose that a single CC promotes folding of the CL domain via nucleation and in-register growth from one end, whereas initiation and growth from both ends in CC-CL-CC results in mismatched registers that frustrate folding. Bioinformatics analysis of natural collagens lends support to this because, where present, there is generally only one coiled-coil domain close to the triple helix, and it is nearly always N-terminal to the collagen repeat. PMID:21454493

  4. EDITORIAL: ECRH physics and technology in ITER

    NASA Astrophysics Data System (ADS)

    Luce, T. C.

    2008-05-01

    : EC wave physics and applications, M. Thumm: Source and transmission line development, and S. Cirant: ITER specific system designs). These summaries are included in this issue to give a more complete view of the technical meeting. Finally, it is appropriate to mention the future of this meeting series. With the ratification of the ITER agreement and the formation of the ITER International Organization, it was recognized that meetings conducted by outside agencies with an exclusive focus on ITER would be somewhat unusual. However, the participants at this meeting felt that the gathering of international experts with diverse specialities within EC wave physics and technology to focus on using EC waves in future fusion devices like ITER was extremely valuable. It was therefore recommended that this series of meetings continue, but with the broader focus on the application of EC waves to steady-state and burning plasma experiments including demonstration power plants. As the papers in this special issue show, the EC community is already taking seriously the challenges of applying EC waves to fusion devices with high neutron fluence and continuous operation at high reliability.

  5. An Iterative Angle Trisection

    ERIC Educational Resources Information Center

    Muench, Donald L.

    2007-01-01

    The problem of angle trisection continues to fascinate people even though it has long been known that it can't be done with straightedge and compass alone. However, for practical purposes, a good iterative procedure can get you as close as you want. In this note, we present such a procedure. Using only straightedge and compass, our procedure…

  6. Iterative software kernels

    SciTech Connect

    Duff, I.

    1994-12-31

    This workshop focuses on kernels for iterative software packages. Specifically, the three speakers discuss various aspects of sparse BLAS kernels. Their topics are: `Current status of user lever sparse BLAS`; Current status of the sparse BLAS toolkit`; and `Adding matrix-matrix and matrix-matrix-matrix multiply to the sparse BLAS toolkit`.

  7. ITER global stability limits

    SciTech Connect

    Hogan, J.T.; Uckan, N.A.

    1990-01-01

    The MHD stability limits to the ITER operational space have been examined with the PEST ideal stability code. Constraints on ITER operation have been examined for the nominal operational scenarios and for possible design variants. Rather than rely on evaluation of a relatively small number of sample cases, the approach has been to construct an approximation to the overall operational space, and to compare this with the observed limits in high-{beta} tokamaks. An extensive database with {approximately}20,000 stability results has been compiled for use by the ITER design team. Results from these studies show that the design values of the Troyon factor (g {approximately} 2.5 for ignition studies, and g {approximately} 3 for the technology phase) which are based on present experiments, are also expected to be attainable for ITER conditions, for which the configuration and wall-stabilisation environment differ from those in present experiments. Strongly peaked pressure profiles lead to degraded high-{beta} performance. Values of g {approximately} 4 are found for higher safety factor (q {sub {Psi}} {le} 4) than that of the present design (q{sub {Psi}} {approximately} 3). Profiles with q(0) < 1 are shown to give g {approximately} 2.5, if the current density profile provides optimum shear. The overall operational spaces are presented for g-q{sub {Psi}}, q{sub {Psi}}-1{sub i}, q-{alpha}{sub p} and l{sub i}-q{sub {psi}}.

  8. Toroid field coil shear key installation study, DOE task No. 22

    SciTech Connect

    Jones, C.E.; Meier, R.W.; Yuen, J.L.

    1995-01-09

    Concepts for fitting and installation of the scissor keys, triangular keys, and truss keys in the ITER Toroidal Field (TF) Coil Assembly were developed and evaluated. In addition, the process of remote removal and replacement of a failed TF coil was considered. Two concepts were addressed: central solenoid installed last (Naka Option 1) and central solenoid installed first (Naka Option 2). In addition, a third concept was developed which utilized the favorable features of both concepts. A time line for installation was estimated for the Naka Option 1 concept.

  9. Transient voltage oscillations in coils

    SciTech Connect

    Chowdhuri, P.

    1985-01-01

    Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated.

  10. The structure of the GemC1 coiled coil and its interaction with the Geminin family of coiled-coil proteins

    SciTech Connect

    Caillat, Christophe; Fish, Alexander; Pefani, Dafni-Eleftheria; Taraviras, Stavros; Lygerou, Zoi; Perrakis, Anastassis

    2015-10-31

    The GemC1 coiled-coil structure has subtle differences compared with its homologues Geminin and Idas. Co-expression experiments in cells and biophysical stability analysis of the Geminin-family coiled coils suggest that the GemC1 coiled coil alone is unstable. GemC1, together with Idas and Geminin, an important regulator of DNA-replication licensing and differentiation decisions, constitute a superfamily sharing a homologous central coiled-coil domain. To better understand this family of proteins, the crystal structure of a GemC1 coiled-coil domain variant engineered for better solubility was determined to 2.2 Å resolution. GemC1 shows a less typical coiled coil compared with the Geminin homodimer and the Geminin–Idas heterodimer structures. It is also shown that both in vitro and in cells GemC1 interacts with Geminin through its coiled-coil domain, forming a heterodimer that is more stable that the GemC1 homodimer. Comparative analysis of the thermal stability of all of the possible superfamily complexes, using circular dichroism to follow the unfolding of the entire helix of the coiled coil, or intrinsic tryptophan fluorescence of a unique conserved N-terminal tryptophan, shows that the unfolding of the coiled coil is likely to take place from the C-terminus towards the N-terminus. It is also shown that homodimers show a single-state unfolding, while heterodimers show a two-state unfolding, suggesting that the dimer first falls apart and the helices then unfold according to the stability of each protein. The findings argue that Geminin-family members form homodimers and heterodimers between them, and this ability is likely to be important for modulating their function in cycling and differentiating cells.

  11. International Thermonuclear Experimental Reactor (ITER) neutral beam design

    SciTech Connect

    Myers, T.J.; Brook, J.W.; Spampinato, P.T.; Mueller, J.P.; Luzzi, T.E.; Sedgley, D.W. . Space Systems Div.)

    1990-10-01

    This report discusses the following topics on ITER neutral beam design: ion dump; neutralizer and module gas flow analysis; vacuum system; cryogenic system; maintainability; power distribution; and system cost.

  12. Electromagnetic Gun With Commutated Coils

    NASA Technical Reports Server (NTRS)

    Elliott, David G.

    1991-01-01

    Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

  13. Method and apparatus for improved high power impulse magnetron sputtering

    DOEpatents

    Anders, Andre

    2013-11-05

    A high power impulse magnetron sputtering apparatus and method using a vacuum chamber with a magnetron target and a substrate positioned in the vacuum chamber. A field coil being positioned between the magnetron target and substrate, and a pulsed power supply and/or a coil bias power supply connected to the field coil. The pulsed power supply connected to the field coil, and the pulsed power supply outputting power pulse widths of greater that 100 .mu.s.

  14. Self assembly of coiled-coil peptide-porphyrin complexes.

    PubMed

    Kokona, Bashkim; Kim, Andrew M; Roden, R Claire; Daniels, Joshua P; Pepe-Mooney, Brian J; Kovaric, Brian C; de Paula, Julio C; Johnson, Karl A; Fairman, Robert

    2009-06-01

    We are interested in the controlled assembly of photoelectronic materials using peptides as scaffolds and porphyrins as the conducting material. We describe the integration of a peptide-based polymer strategy with the ability of designed basic peptides to bind anionic porphyrins in order to create regulated photoelectronically active biomaterials. We have described our peptide system in earlier work, which demonstrates the ability of a peptide to form filamentous materials made up of self-assembling coiled-coil structures. We have modified this peptide system to include lysine residues appropriately positioned to specifically bind meso-tetrakis(4-sulfonatophenyl)porphine (TPPS(4)), a porphyrin that contains four negatively charged sulfonate groups at neutral pH. We measure the binding of TPPS(4) to our peptide using UV--visible and fluorescence spectroscopies to follow the porphyrin signature. We determine the concomitant acquisition of helical secondary structure in the peptide upon TPPS(4) binding using circular dichroism spectropolarimetry. This binding fosters polymerization of the peptide, as shown by absorbance extinction effects in the peptide CD spectra. The morphologies of the peptide/porphyrin complexes, as imaged by atomic force microscopy, are consistent with the coiled-coil polymers that we had characterized earlier, except that the heights are slightly higher, consistent with porphyrin binding. Evidence for exciton coupling in the copolymers is shown by red-shifting in the UV--visible data, however, the coupling is weak based on a lack of fluorescence quenching in fluorescence experiments.

  15. Current-bounded commutation of a long-stroke magnetically levitated stage with moving coils

    NASA Astrophysics Data System (ADS)

    Zhu, Yu; Zhang, Shengguo; Yang, Kaiming; Mu, Haihua; Yin, Wensheng

    2012-11-01

    Magnetically levitated stages(MLS) have potentials to obtain good motion performances in high vacuum environment. Yet the electromagnetic forces/torques corresponding to six degrees of freedom(DOF) motions have coupling relationship with each current of coil array, and this coupling is still associated with the relative positions between the mover and the stator of the stage. So it is quite difficult to control the 6-DOF motions of the stage. By reasonable commutation of coil array, this complicated coupling relationship can be decoupled. The analytical force/torque-decomposing model of the stage is established first. Then the initial currents of coil array are commutated based on the pseudo inverse of the analytical force/torque-decomposing model matrix. And then the coil array currents are commutated again with different current bounds given to the initial currents as well as in the sense of minimum 2-norm of currents vector. Using the long stroke magnetically levitated stage with moving coils under investigation as examples, the currents of coil array are commutated with different current bounds adopting the proposed commutation method, the determination of current bound and the current bounds' influences on the heat-losses in coil array are analyzed, and the effectiveness of implementation algorithm of proposed commutation method is discussed. Simulation, analysis and discussion results indicate that the currents of coil array within the given current bound can be solved analytically by proposed commutation method, and the implementation algorithm does not need any searching or iteration. By the current-bounded commutation method proposed, the amplitude of coil array currents can be limited within an appropriate current bound(This is very beneficial to the improvement of the reliability and motion performance of the stage), as well as these currents can also generate the desired forces and torques.

  16. German COIL efforts: status and perspectives

    NASA Astrophysics Data System (ADS)

    Bohn, Willy L.

    2002-05-01

    Historically, COIL research in Germany has started with microwave excitation of an oxygen flow. But soon all efforts have been devoted to the chemical generation of excited singlet oxygen and have eventually given rise to a supersonic 10 kW class rotating disk driven device. A diode based diagnostic provides data of small signal gain and cavity temperature which emphasize the role of iodine injection for different penetration conditions. Heat release can lead to substantially higher temperatures as expected from adiabatic expansion. Power extraction is found to be in good agreement with theoretical predictions. Alternatively, small scale liquid jet generator experiments show encouraging 60 percent efficiency. Besides air defense related applications and a study on space debris removal, results are given which are pertinent to the decommissioning of nuclear installations. In particular, laser cutting of concrete at 1.3 micrometers is demonstrated and theoretically scaled up to relevant power levels.

  17. [Two Cases of Ruptured Cerebral Aneurysm Complicated with Delayed Coil Protrusion after Coil Embolization].

    PubMed

    Furukawa, Takashi; Ogata, Atsushi; Ebashi, Ryo; Takase, Yukinori; Masuoka, Jun; Kawashima, Masatou; Abe, Tatsuya

    2016-07-01

    We report two cases of delayed coil protrusion after coil embolization for ruptured cerebral aneurysms. Case 1:An 82-year-old woman with a subarachnoid hemorrhage due to a ruptured small anterior communicating artery aneurysm underwent successful coil embolization. Eighteen days after the procedure, coil protrusion from the aneurysm into the right anterior cerebral artery was observed without any symptoms. Further coil protrusion did not develop after 28 days. Case 2:A 78-year-old woman with a subarachnoid hemorrhage due to a ruptured small left middle cerebral artery aneurysm underwent successful coil embolization. Twenty days after the procedure, coil protrusion from the aneurysm into the left middle cerebral artery was observed, with a transient ischemic attack. Further coil protrusion did not develop. Both patients recovered with antithrombotic treatment. Even though delayed coil protrusion after coil embolization is rare, it should be recognized as a long-term complication of coil embolization for cerebral aneurysms. PMID:27384117

  18. Coil Embolization for Intracranial Aneurysms

    PubMed Central

    2006-01-01

    Executive Summary Objective To determine the effectiveness and cost-effectiveness of coil embolization compared with surgical clipping to treat intracranial aneurysms. The Technology Endovascular coil embolization is a percutaneous approach to treat an intracranial aneurysm from within the blood vessel without the need of a craniotomy. In this procedure, a microcatheter is inserted into the femoral artery near the groin and navigated to the site of the aneurysm. Small helical platinum coils are deployed through the microcatheter to fill the aneurysm, and prevent it from further expansion and rupture. Health Canada has approved numerous types of coils and coil delivery systems to treat intracranial aneurysms. The most favoured are controlled detachable coils. Coil embolization may be used with other adjunct endovascular devices such as stents and balloons. Background Intracranial Aneurysms Intracranial aneurysms are the dilation or ballooning of part of a blood vessel in the brain. Intracranial aneurysms range in size from small (<12 mm in diameter) to large (12–25 mm), and to giant (>25 mm). There are 3 main types of aneurysms. Fusiform aneurysms involve the entire circumference of the artery; saccular aneurysms have outpouchings; and dissecting aneurysms have tears in the arterial wall. Berry aneurysms are saccular aneurysms with well-defined necks. Intracranial aneurysms may occur in any blood vessel of the brain; however, they are most commonly found at the branch points of large arteries that form the circle of Willis at the base of the brain. In 85% to 95% of patients, they are found in the anterior circulation. Aneurysms in the posterior circulation are less frequent, and are more difficult to treat surgically due to inaccessibility. Most intracranial aneurysms are small and asymptomatic. Large aneurysms may have a mass effect, causing compression on the brain and cranial nerves and neurological deficits. When an intracranial aneurysm ruptures and bleeds

  19. Power and particle exhaust in tokamaks

    SciTech Connect

    Stambaugh, R.D.

    1998-01-01

    The status of power and particle exhaust research in tokamaks is reviewed in the light of ITER requirements. There is a sound basis for ITER`s nominal design positions; important directions for further research are identified.

  20. A MRI rotary phased array head coil.

    PubMed

    Li, Bing Keong; Weber, Ewald; Crozier, Stuart

    2013-08-01

    A new rotary phased array (RPA) head coil that can provide homogenous brain images comparable to volumetric radiofrequency coils is proposed for magnetic resonance brain imaging applications. The design of the RPA head coil is a departure from conventional circumferential array design method, as coil elements of the RPA head coil have a "paddle-like" structure consisting of a pair of main conductors located on opposite sides, inserted equi-angularly around and over the head. A prototype 2T receive-only 4-element RPA head coil was constructed and experimentally tested against a conventional receive-only 4-element phased array head coil and a commercial receive-only quadrature birdcage head coil. Homogenous phantom images acquired by the RPA head coil show that signal intensity deep at the center of the phantom was improved as compared to the conventional phased array head coil and this improvement allow the RPA head coil to acquire homogenous brain images similar to brain images acquired with the birdcage head coil. In addition, partial parallel imaging was used in conjunction with the RPA head coil to enable rapid imaging.

  1. Large coil test facility

    SciTech Connect

    Nelms, L.W.; Thompson, P.B.

    1980-01-01

    Final design of the facility is nearing completion, and 20% of the construction has been accomplished. A large vacuum chamber, houses the test assembly which is coupled to appropriate cryogenic, electrical, instrumentation, diagnostc systems. Adequate assembly/disassembly areas, shop space, test control center, offices, and test support laboratories are located in the same building. Assembly and installation operations are accomplished with an overhead crane. The major subsystems are the vacuum system, the test stand assembly, the cryogenic system, the experimental electric power system, the instrumentation and control system, and the data aquisition system.

  2. Progress on the Coupling Coil for the MICE Channel

    SciTech Connect

    Green, M.A.; Li, D.; Virostek, S.P.; Lau, W.; Witte, H.; Yang,S.Q.; Drumm, P.; Ivanyushenkov, Y.

    2005-05-08

    This report describes the progress on the coupling magnet for the international Muon Ionization Cooling Experiment (MICE). MICE consists of two cells of a SFOFO cooling channel that is similar to that studied in the level 2 study of a neutrino factory. The MICE RF coupling coil module (RFCC module) consists of a 1.56 m diameter superconducting solenoid, mounted around four cells of conventional 201.25 MHz closed RF cavities. This report discusses the progress that has been made on the superconducting coupling coil that is around the center of the RF coupling module. This report describes the process by which one would cool the coupling coil using a single small 4 K cooler. In addition, the coupling magnet power system and quench protection system are also described.

  3. Experimental studies of ITER demonstration discharges

    NASA Astrophysics Data System (ADS)

    Sips, A. C. C.; Casper, T. A.; Doyle, E. J.; Giruzzi, G.; Gribov, Y.; Hobirk, J.; Hogeweij, G. M. D.; Horton, L. D.; Hubbard, A. E.; Hutchinson, I.; Ide, S.; Isayama, A.; Imbeaux, F.; Jackson, G. L.; Kamada, Y.; Kessel, C.; Kochl, F.; Lomas, P.; Litaudon, X.; Luce, T. C.; Marmar, E.; Mattei, M.; Nunes, I.; Oyama, N.; Parail, V.; Portone, A.; Saibene, G.; Sartori, R.; Stober, J. K.; Suzuki, T.; Wolfe, S. M.; C-Mod Team; ASDEX Upgrade Team; DIII-D Team; JET EFDA Contributors

    2009-08-01

    Key parts of the ITER scenarios are determined by the capability of the proposed poloidal field (PF) coil set. They include the plasma breakdown at low loop voltage, the current rise phase, the performance during the flat top (FT) phase and a ramp down of the plasma. The ITER discharge evolution has been verified in dedicated experiments. New data are obtained from C-Mod, ASDEX Upgrade, DIII-D, JT-60U and JET. Results show that breakdown for Eaxis < 0.23-0.33 V m-1 is possible unassisted (ohmic) for large devices like JET and attainable in devices with a capability of using ECRH assist. For the current ramp up, good control of the plasma inductance is obtained using a full bore plasma shape with early X-point formation. This allows optimization of the flux usage from the PF set. Additional heating keeps li(3) < 0.85 during the ramp up to q95 = 3. A rise phase with an H-mode transition is capable of achieving li(3) < 0.7 at the start of the FT. Operation of the H-mode reference scenario at q95 ~ 3 and the hybrid scenario at q95 = 4-4.5 during the FT phase is documented, providing data for the li (3) evolution after the H-mode transition and the li (3) evolution after a back-transition to L-mode. During the ITER ramp down it is important to remain diverted and to reduce the elongation. The inductance could be kept <=1.2 during the first half of the current decay, using a slow Ip ramp down, but still consuming flux from the transformer. Alternatively, the discharges can be kept in H-mode during most of the ramp down, requiring significant amounts of additional heating.

  4. Design of a toroidal plasma confinement device with a levitated super-conducting internal coil

    SciTech Connect

    Ogawa, Y.; Morikawa, J.; Himura, H.; Kondoh, S.; Yoshida, Z.; Mito, T.; Yanagi, N.; Iwakuma, N.

    1999-12-10

    A toroidal device has been constructed and nonneutral plasma experiments have been intensively promoted, where an internal ring coil with a copper conductor has been employed. We are now designing a toroidal plasma trapping device with a levitated superconducting internal coil, so as to avoid plasma loss through current-lead and support structures of the internal coil. Typical machine parameters are as follows; the major radius of the internal ring coil is 40 cm and the coil current is 500 kA. Concerning to the levitated coil, the high-temperature (high-Tc) super-conducting coil is preferable for plasma experiments, because long pulse and/or high power heating experiments might be available due to the good property for the thermal stability and large heat capacity of the high-Tc super-conducting coil. Our primary candidate is Bi-2223 super-conducting cable. Since the maximum magnetic field strength is around 2 T in our device, the deterioration of the critical current is not so severe up to 40 K. We are now promoting a detailed design of the toroidal device with a high-Tc super-conducting internal coil.

  5. Design of a Toroidal Plasma Confinement Device with a Levitated Super-Conducting Internal Coil

    SciTech Connect

    Y. Ogawa; H. Himura; S. Kondoh; J. Morikawa; Z. Yoshida

    1999-12-31

    A toroidal device has been constructed and nonneutral plasma experiments have been intensively promoted, where an internal ring coil with a copper conductor has been employed. We are now designing a toroidal plasma trapping device with a levitated superconducting internal coil, so as to avoid plasma loss through current-lead and support structures of the internal coil. Typical machine parameters are as follows; the major radius of the internal ring coil is 40 cm and the coil current is 500 kA. Concerning to the levitated coil, the high-temperature (high-Tc) super-conducting coil is preferable for plasma experiments, because long pulse and/or high power heating experiments might be available due to the good property for the thermal stability and large heat capacity of the high-Tc super-conducting coil. Our primary candidate is Bi-2223 super-conducting cable. Since the maximum magnetic field strength is around 2 T in our device, the deterioration of the critical current is not so severe up to 40 K. We are now promoting a detailed design of the toroidal device with a high-Tc super-conducting internal coil.

  6. Testing of machine wound second generation HTS tape Vacuum Pressure Impregnated coils

    NASA Astrophysics Data System (ADS)

    Swaffield, D.; Lewis, C.; Eugene, J.; Ingles, M.; Peach, D.

    2014-05-01

    Delamination of second generation (2G) High Temperature Superconducting (HTS) tapes has previously been reported when using resin based insulation systems for wound coils. One proposed root cause is the differential thermal contraction between the coil former and the resin encapsulated coil turns resulting in the tape c-axis tensile stress being exceeded. Importantly, delamination results in unacceptable degradation of the superconductor critical current level. To mitigate the delamination risk and prove winding, jointing and Vacuum Pressure Impregnation (VPI) processes in the production of coils for superconducting rotating machines at GE Power Conversion two scaled trial coils have been wound and extensively tested. The coils are wound from 12mm wide 2G HTS tape supplied by AMSC onto stainless steel 'racetrack' coil formers. The coils are wound in two layers which include both in-line and layer-layer joints subject to in-process test. The resin insulation system chosen is VPI and oven cured. Tests included; insulation resistance, repeat quench and recovery of the superconductor, heat runs and measurement of n-value, before and after multiple thermal cycling between ambient and 35 Kelvin. No degradation of coil performance is evidenced.

  7. Improved Voice-Coil Actuators Have Lower Copper Losses

    NASA Technical Reports Server (NTRS)

    Simizu, Satoru; Pourarian, Faiz; Boltich, Edwin B.; Sankar, Suryanarayan G.

    1990-01-01

    Improved design concept for electromagnetic linear-motion actuators of loudspeaker-voice-coil type reduces both copper losses (dissipation of power in electrical resistances of windings) and magnetic interference with other equipment. Includes closed magnetic circuit, which suppresses fringing flux. Pr/Fe/B permanent magnets yield better performance at lower temperatures. Intended for use where power supplies limited, heating must be minimized, and/or adequate performance at temperatures far below ambient required.

  8. Anchor Coil Technique for Arteriovenous Fistula Embolization

    PubMed Central

    Kanemaru, Kazuya; Ezura, Masayuki; Nishiyama, Yoshihisa; Yagi, Takashi; Yoshioka, Hideyuki; Fukumoto, Yuichiro; Horikoshi, Toru; Kinouch, Hiroyuki

    2014-01-01

    Summary We describe a case of arteriovenous fistula (AVF) successfully treated by coil embolization with an anchor coil inserted in the varix to facilitate dense packing at the shunting site. AVF of the left anterior choroidal artery (AChoA) draining into the ipsilateral basal vein of Rosenthal was incidentally found in a newborn female. A single detachable coil was inserted as an anchor into the varix adjacent to the shunt, and the microcatheter was pulled back to the shunting point. Three more detachable coils were delivered at the shunting point without migration under the support of the anchor coil, and the AVF was successfully obliterated with preservation of AChoA blood flow. The anchor coil technique can reduce the risk of coil migration and the number of coils required. PMID:24976089

  9. Alternating current losses in superconducting coils

    NASA Technical Reports Server (NTRS)

    Wipf, S. L.; Guderjahn, C. A.

    1972-01-01

    Report examines relationship between coil loss and frequency and heat loss in coil as a function of the magnetic field H. Information is of value to manufacturers of superconducting magnets, motors and generators.

  10. Coupled Coils, Magnets and Lenz's Law

    ERIC Educational Resources Information Center

    Thompson, Frank

    2010-01-01

    Great scientists in the past have experimented with coils and magnets. Here we have a variation where coupling occurs between two coils and the oscillatory motion of two magnets to give somewhat surprising results. (Contains 6 figures and 1 footnote.)

  11. Suppression of type-I ELMs with reduced RMP coil set on DIII-D

    DOE PAGES

    Orlov, D. M.; Moyer, R. A.; Evans, T. E.; Paz-Soldan, Carlos; Ferraro, N. M.; Nazikian, R.; deGrassie, John S.; Grierson, Brian A.; Eldon, D.; Fenstermacher, Max E.; et al

    2016-02-19

    Recent experiments on DIII-D have demonstrated that having a toroidally-monochromatic spectral content of edge-resonant magnetic perturbations (RMPs) is not a necessary condition for suppression of edge localized modes (ELMs). Robust ELM suppression has been reproducibly obtained on DIII-D during experiments in which various non-axisymmetric coil loops were turned off pseudo-randomly producing a variety of n=1 , n=2, and n=3 spectral contributions. It was demonstrated that RMP ELM suppression could be achieved with as few as 5 out of 12 internal coil loops (I-coils) on DIII-D at similar coil currents and with good plasma confinement. Linear MHD plasma response (M3DC1, IPEC,more » MARS) and vacuum (SURFMN, TRIP3D) modelling have been performed in order to understand the effects of the perturbation spectrum on the plasma response and ELM suppression. The results suggest that reduction of the dominant n=3 perturbation field is compensated by increased n=2 field in the plasma that may lead to RMP ELM suppression at lower levels of n=3 perturbative magnetic flux from the I-coils. In conclusion, these results provide additional confidence that ITER may be capable of RMP ELM suppression in the event of multiple internal coil failures.« less

  12. Suppression of type-I ELMs with reduced RMP coil set on DIII-D

    NASA Astrophysics Data System (ADS)

    Orlov, D. M.; Moyer, R. A.; Evans, T. E.; Paz-Soldan, C.; Ferraro, N. M.; Nazikian, R.; deGrassie, J. S.; Grierson, B. A.; Eldon, D.; Fenstermacher, M. E.; King, J. D.; Logan, N. C.; Lanctot, M. J.; Maingi, R.; Snyder, P. B.; Strait, E. J.; Wingen, A.

    2016-03-01

    Recent experiments on DIII-D have demonstrated that having a toroidally-monochromatic spectral content of edge-resonant magnetic perturbations (RMPs) is not a necessary condition for suppression of edge localized modes (ELMs). Robust ELM suppression has been reproducibly obtained on DIII-D during experiments in which various non-axisymmetric coil loops were turned off pseudo-randomly producing a variety of n=1 , n= 2 , and n= 3 spectral contributions. It was shown that RMP ELM suppression could be achieved with as few as 5 out of 12 internal coil loops (I-coils) on DIII-D at similar coil currents and with good plasma confinement. Linear MHD plasma response (m3dc1, ipec, mars) and vacuum (surfmn, trip3d) modelling have been performed in order to understand the effects of the perturbation spectrum on the plasma response and ELM suppression. The results suggest that reduction of the dominant n= 3 perturbation field is compensated by increased n= 2 field in the plasma that may lead to RMP ELM suppression at lower levels of n= 3 perturbative magnetic flux from the I-coils. These results provide additional confidence that ITER may be capable of RMP ELM suppression in the event of multiple internal coil failures.

  13. Bow-shaped toroidal field coils

    SciTech Connect

    Bonanos, P.

    1981-05-01

    Design features of Bow-Shaped Toroidal Field Coils are described and compared with circular and D shaped coils. The results indicate that bow coils can produce higher field strengths, store more energy and be made demountable. The design offers the potential for the production of ultrahigh toroidal fields. Included are representative coil shapes and their engineering properties, a suggested structural design and an analysis of a specific case.

  14. Rotor assembly including superconducting magnetic coil

    DOEpatents

    Snitchler, Gregory L.; Gamble, Bruce B.; Voccio, John P.

    2003-01-01

    Superconducting coils and methods of manufacture include a superconductor tape wound concentrically about and disposed along an axis of the coil to define an opening having a dimension which gradually decreases, in the direction along the axis, from a first end to a second end of the coil. Each turn of the superconductor tape has a broad surface maintained substantially parallel to the axis of the coil.

  15. Multi-Canted Coils, Tubes, and Structures

    NASA Technical Reports Server (NTRS)

    Jaster, Mark L. (Inventor)

    2015-01-01

    Coil, tube, and other structures configured with a plurality of individual coils, internal structures, legs or extensions with each having multiple cants per coil, internal structure, leg or extension, and wherein the cants formed therein allow for a load-deflection force when each is compressed. In addition, any horizontal or moment forces are substantially reduced and/or eliminated when a downward vertical force is applied, as minimal or no torsion is created in the individual coils, legs or extensions.

  16. Design and modelling of a SMES coil

    NASA Astrophysics Data System (ADS)

    Yuan, Weijia; Campbell, A. M.; Coombs, T. A.

    2010-06-01

    The design of a Superconducting Magnetic Energy Storage (SMES) coil wound by coated conductors has been presented. Based on an existing model for coated conductor pancake coils, this paper analysed the magnetic field and current density distribution of the coil at two different operation temperatures, 77K and 22K. A comparison table of the critical currents and AC losses at these two temperatures has been presented. Several steps to improve the transport current of the coil have been suggested as well.

  17. Modeling ITER ECH Waveguide Performance

    NASA Astrophysics Data System (ADS)

    Kaufman, M. C.; Lau, C. H.

    2014-10-01

    There are stringent requirements for mode purity and for on-target power as a percentage of source power for the ECH transmission lines on ITER. The design goal is less than 10% total power loss through the line and 95% HE11 mode at the diamond window. The dominant loss mechanism is mode conversion (MC) into higher order modes, and to maintain mode purity, these losses must be minimized. Miter bends and waveguide curvature are major sources of mode conversion. This work uses a code which calculates the mode conversion and attenuation of an arbitrary set of polarized waveguide modes in circular corrugated waveguide with non-zero axial curvature and miter bends. The transmission line is modeled as a structural beam with deformations due to misalignment of waveguide supports, tilts at the interfaces between waveguide sections, gravitational loading, and the extrusion and fabrication process. As these sources of curvature are statistical in nature, the resulting MC losses are found via Monte Carlo modeling. The results of this analysis will provide design guidance for waveguide support span lengths, requirements for minimum alignment offsets, and requirements for waveguide fabrication and quality control.

  18. Split Coil Forms for Rotary Transformers

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W. T.

    1982-01-01

    Split cores for rotor and stator windings of rotary transformer mounted around their respective coils (which are in bobbins) and cemented together. This arrangement simplifies winding of stator coil to go in a slot in inner diameter of stator coil. One practical application of rotary transformers fabricated according to this technique is for centrifuges, in which conventional sliprings are of uncertain reliability.

  19. DATA ACQUISITION AND PROTECTION FOR NEW DII-D IN-VESSEL COILS

    SciTech Connect

    CAMPBELL,G.L; SZYMANSKI,D.D; PIGLOWSKI,D.A; KELLMAN,D.H; ANDERSON,P.M; JACKSON,G.L; KELLMAN,A.G

    2003-10-01

    OAK-B135 The installation of new internal magnetic coils (I-Coils) in the DIII-D tokamak at General Atomics required extensive additions to the experiment data acquisition and protection capabilities. This set of 12 coils (up to 7 kA each) is designed to allow improved feedback stabilization of resistive wall modes which limit the plasma performance. The acquisition and signal conditions needs of the I-Coil power system presented an opportunity to try a new data acquisition approach which increased both the sampling rate and sample size per channel compared to the standard DIII-D CAMAC acquisition equipment. A 96 channel Compact-PCI (cPCI) digitizer system was purchased for the I-Coil project to acquire up to approximately 380 MB of power supply and coil current data per plasma discharge. Additional instrumentation and control was provided to protect personnel, the new coils, the tokamak, the facility and improve machine availability. This paper will present discussions of technical and programmatic requirements, based for requirements, the design selection outcome, installation experience, integration issues, commissioning experience, and lessons learned. The data acquisition system is described in detail including a conservative signal isolation scheme, signal grounding standards, anti-aliasing filters, and synchronization of acquisition. Protection interlocks are described, including high voltage isolation, water flow measurement, and the coil grounding-shorting switches.

  20. Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators.

    PubMed

    Khan, Sadeque Reza; Choi, GoangSeog

    2016-01-01

    High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8%) than circular resonators (78.43%) when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW) to the load than the square coils (396 mW) under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation. PMID:27527169

  1. Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators

    PubMed Central

    Khan, Sadeque Reza; Choi, GoangSeog

    2016-01-01

    High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8%) than circular resonators (78.43%) when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW) to the load than the square coils (396 mW) under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation. PMID:27527169

  2. Adaptive iterative reconstruction

    NASA Astrophysics Data System (ADS)

    Bruder, H.; Raupach, R.; Sunnegardh, J.; Sedlmair, M.; Stierstorfer, K.; Flohr, T.

    2011-03-01

    It is well known that, in CT reconstruction, Maximum A Posteriori (MAP) reconstruction based on a Poisson noise model can be well approximated by Penalized Weighted Least Square (PWLS) minimization based on a data dependent Gaussian noise model. We study minimization of the PWLS objective function using the Gradient Descent (GD) method, and show that if an exact inverse of the forward projector exists, the PWLS GD update equation can be translated into an update equation which entirely operates in the image domain. In case of non-linear regularization and arbitrary noise model this means that a non-linear image filter must exist which solves the optimization problem. In the general case of non-linear regularization and arbitrary noise model, the analytical computation is not trivial and might lead to image filters which are computationally very expensive. We introduce a new iteration scheme in image space, based on a regularization filter with an anisotropic noise model. Basically, this approximates the statistical data weighting and regularization in PWLS reconstruction. If needed, e.g. for compensation of the non-exactness of backprojector, the image-based regularization loop can be preceded by a raw data based loop without regularization and statistical data weighting. We call this combined iterative reconstruction scheme Adaptive Iterative Reconstruction (AIR). It will be shown that in terms of low-contrast visibility, sharpness-to-noise and contrast-to-noise ratio, PWLS and AIR reconstruction are similar to a high degree of accuracy. In clinical images the noise texture of AIR is also superior to the more artificial texture of PWLS.

  3. Quantum iterated function systems.

    PubMed

    Łoziński, Artur; Zyczkowski, Karol; Słomczyński, Wojciech

    2003-10-01

    An iterated function system (IFS) is defined by specifying a set of functions in a classical phase space, which act randomly on an initial point. In an analogous way, we define a quantum IFS (QIFS), where functions act randomly with prescribed probabilities in the Hilbert space. In a more general setting, a QIFS consists of completely positive maps acting in the space of density operators. This formalism is designed to describe certain problems of nonunitary quantum dynamics. We present exemplary classical IFSs, the invariant measure of which exhibits fractal structure, and study properties of the corresponding QIFSs and their invariant states.

  4. Iterative Magnetometer Calibration

    NASA Technical Reports Server (NTRS)

    Sedlak, Joseph

    2006-01-01

    This paper presents an iterative method for three-axis magnetometer (TAM) calibration that makes use of three existing utilities recently incorporated into the attitude ground support system used at NASA's Goddard Space Flight Center. The method combines attitude-independent and attitude-dependent calibration algorithms with a new spinning spacecraft Kalman filter to solve for biases, scale factors, nonorthogonal corrections to the alignment, and the orthogonal sensor alignment. The method is particularly well-suited to spin-stabilized spacecraft, but may also be useful for three-axis stabilized missions given sufficient data to provide observability.

  5. MLP iterative construction algorithm

    NASA Astrophysics Data System (ADS)

    Rathbun, Thomas F.; Rogers, Steven K.; DeSimio, Martin P.; Oxley, Mark E.

    1997-04-01

    The MLP Iterative Construction Algorithm (MICA) designs a Multi-Layer Perceptron (MLP) neural network as it trains. MICA adds Hidden Layer Nodes one at a time, separating classes on a pair-wise basis, until the data is projected into a linear separable space by class. Then MICA trains the Output Layer Nodes, which results in an MLP that achieves 100% accuracy on the training data. MICA, like Backprop, produces an MLP that is a minimum mean squared error approximation of the Bayes optimal discriminant function. Moreover, MICA's training technique yields novel feature selection technique and hidden node pruning technique

  6. Development of the Butt Joint for the ITER Central Solenoid

    SciTech Connect

    Martovetsky, N N

    2006-08-23

    The ITER Central Solenoid (CS) requires compact and reliable joints for its Cable-in-Conduit Conductor (CICC). The baseline design is a diffusion bonded butt joint. In such a joint the mating cables are compacted to a very low void fraction in a copper sleeve and then heat treated. After the heat treatment the ends are cut, polished and aligned against each other and then diffusion bonded under high compression in a vacuum chamber at 750 C. The jacket is then welded on the conductor to complete the joint, which remarkably does not require more room than a regular conductor. This joint design is based on a proven concept developed for the ITER CS Model Coil that was successfully tested in the previous R&D phase.

  7. Three-dimensional coil inductor

    DOEpatents

    Bernhardt, Anthony F.; Malba, Vincent

    2002-01-01

    A three-dimensional coil inductor is disclosed. The inductor includes a substrate; a set of lower electrically conductive traces positioned on the substrate; a core placed over the lower traces; a set of side electrically conductive traces laid on the core and the lower traces; and a set of upper electrically conductive traces attached to the side traces so as to form the inductor. Fabrication of the inductor includes the steps of forming a set of lower traces on a substrate; positioning a core over the lower traces; forming a set of side traces on the core; connecting the side traces to the lower traces; forming a set of upper traces on the core; and connecting the upper traces to the side traces so as to form a coil structure.

  8. On the safety of ITER accelerators

    PubMed Central

    Li, Ge

    2013-01-01

    Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate −1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER. PMID:24008267

  9. Mission of ITER and Challenges for the Young

    SciTech Connect

    Ikeda, Kaname

    2009-02-19

    It is recognized that the ongoing effort to provide sufficient energy for the wellbeing of the globe's population and to power the world economy is of the greatest importance. ITER is a joint international research and development project that aims to demonstrate the scientific and technical feasibility of fusion power. It represents the responsible actions of governments whose countries comprise over half the world's population, to create fusion power as a source of clean, economic, carbon dioxide-free energy. This is the most important science initiative of our time.The partners in the Project--the ITER Parties--are the European Union, Japan, the People's Republic of China, India, the Republic of Korea, the Russian Federation and the USA. ITER will be constructed in Europe, at Cadarache in the South of France. The talk will illustrate the genesis of the ITER Organization, the ongoing work at the Cadarache site and the planned schedule for construction. There will also be an explanation of the unique aspects of international collaboration that have been developed for ITER.Although the present focus of the project is construction activities, ITER is also a major scientific and technological research program, for which the best of the world's intellectual resources is needed. Challenges for the young, imperative for fulfillment of the objective of ITER will be identified. It is important that young students and researchers worldwide recognize the rapid development of the project, and the fundamental issues that must be overcome in ITER.The talk will also cover the exciting career and fellowship opportunities for young people at the ITER Organization.

  10. Mission of ITER and Challenges for the Young

    NASA Astrophysics Data System (ADS)

    Ikeda, Kaname

    2009-02-01

    It is recognized that the ongoing effort to provide sufficient energy for the wellbeing of the globe's population and to power the world economy is of the greatest importance. ITER is a joint international research and development project that aims to demonstrate the scientific and technical feasibility of fusion power. It represents the responsible actions of governments whose countries comprise over half the world's population, to create fusion power as a source of clean, economic, carbon dioxide-free energy. This is the most important science initiative of our time. The partners in the Project—the ITER Parties—are the European Union, Japan, the People's Republic of China, India, the Republic of Korea, the Russian Federation and the USA. ITER will be constructed in Europe, at Cadarache in the South of France. The talk will illustrate the genesis of the ITER Organization, the ongoing work at the Cadarache site and the planned schedule for construction. There will also be an explanation of the unique aspects of international collaboration that have been developed for ITER. Although the present focus of the project is construction activities, ITER is also a major scientific and technological research program, for which the best of the world's intellectual resources is needed. Challenges for the young, imperative for fulfillment of the objective of ITER will be identified. It is important that young students and researchers worldwide recognize the rapid development of the project, and the fundamental issues that must be overcome in ITER. The talk will also cover the exciting career and fellowship opportunities for young people at the ITER Organization.

  11. Coiled transmission line pulse generators

    DOEpatents

    McDonald, Kenneth Fox

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  12. Underbalanced coiled tubing sidetrack successful

    SciTech Connect

    Adam, J.; Berry, M.

    1995-12-18

    The technique of drilling through a completion string, underbalanced, with coiled tubing eliminated some of the problems encountered with overbalanced drilling in a group of offset wells. This project confirmed that performing drilling operations in live wells can be carried out safely and effectively. Dalen is a sour gas field in the eastern part of The Netherlands and produces from vertical fractures in the Zechstein carbonate reservoir. The proposal for Dalen 2 was to abandon the lower section of the original hole and subsequently sidetrack conventionally to the top of the reservoir, run and cement a 5-in. liner, complete the well with a 5-in. monobore completion, and install the christmas tree. This part of the operation would be performed with a workover hoist. Thereafter, a 3 3/4-in. hole would be drilled through the completion and into the reservoir, underbalanced with coiled tubing. The drilling proposal had to address a number of key issues: creating underbalanced conditions; handling sour gas production at surface; handling and treating drilling fluids at surface; removing drilled solids from the returned fluid system; and deploying a long coiled tubing drilling bottom hole assembly (BHA) into a live well. The paper discusses planning, legislative issues, well preparation, the drilling program, and lessons learned.

  13. Operating Characteristics in DIII-D ELM-Suppressed RMP H-modes with ITER Similar Shapes

    SciTech Connect

    Evans, T E; Fenstermacher, M E; Jakubowski, M; Moyer, R A; Osborne, T H; Schaffer, M J; Schmitz, O; Watkins, J G; Zeng, L; Baylor, L R; Boedo, J A; Burrell, K H; deGrassie, J S; Gohil, P; Joseph, I; Lasnier, C J; Leonard, A W; Mordijck, S; Petty, C C; Pinsker, R I; Rhodes, T L; Rost, J C; Snyder, P B; Unterberg, E; West, W P

    2008-10-13

    Fast energy transients, incident on the DIII-D divertors due to Type-I edge localized modes (ELMs), are eliminated using small dc currents in a simple set of non-axisymmetric coils that produce edge resonant magnetic perturbations (RMP). In ITER similar shaped (ISS) plasmas, with electron pedestal collisionalities matched to those expected in ITER a sharp resonant window in the safety factor at the 95 percent normalized poloidal flux surface is observed for ELM suppression at q{sub 95}=3.57 with a minimum width {delta}q{sub 95} of {+-}0.05. The size of this resonant window has been increased by a factor of 4 in ISS plasmas by increasing the magnitude of the current in an n=3 coil set along with the current in a separate n=1 coil set. The resonant ELM-suppression window is highly reproducible for a given plasma shape, coil configuration and coil current but can vary with other operating conditions such as {beta}{sub N}. Isolated resonant windows have also been found at other q95 values when using different RMP coil configurations. For example, when the I-coil is operated in an n=3 up-down asymmetric configuration rather than an up-down symmetric configuration a resonant window is found near q{sub 95}=7.4. A Fourier analysis of the applied vacuum magnetic field demonstrates a statistical correlation between the Chirikov island overlap parameter and ELM suppression. These results have been used as a guide for RMP coil design studies in various ITER operating scenarios.

  14. Power supply

    DOEpatents

    Hart, Edward J.; Leeman, James E.; MacDougall, Hugh R.; Marron, John J.; Smith, Calvin C.

    1976-01-01

    An electric power supply employs a striking means to initiate ferroelectric elements which provide electrical energy output which subsequently initiates an explosive charge which initiates a second ferroelectric current generator to deliver current to the coil of a magnetic field current generator, creating a magnetic field around the coil. Continued detonation effects compression of the magnetic field and subsequent generation and delivery of a large output current to appropriate output loads.

  15. A novel electric design for electromagnetic stimulation--the Slinky coil.

    PubMed

    Ren, C; Tarjan, P P; Popović, D B

    1995-09-01

    A novel coil design for inductive electromagnetic stimulation of neural cells has been simulated and experimentally tested. This coil improves the focal effect of a magnetic stimulator, and it reduces its inductance, hence the efficiency of the system is improved. The basic structure of the device is derived from the popular "Slinky" toy. The actual device is formed by winding different numbers of loops forming a helical coil on a half torus. The loops are bunched at the axis of the torus. The coil, due to its geometry, generates a unique distribution of eddy currents in nearby tissues which is favorable compared to a solenoid type stimulator. This renders the Slinky coil more selective than conventional coils used for magnetic stimulation. The distribution of eddy currents was analyzed using Matlab, following Faraday's Law of Induction. Improved focality permits the current through the coil to be reduced for the same effect. In addition, the reduced inductance of the Slinky coil decreases the power requirement; thus, the improved efficiency of the system may allow the generation of bursts of pulses, and expand the utilization of the system to possible functional activation of certain neuro-muscular structures when peripheral nerves are stimulated.

  16. COIL--Chemical Oxygen Iodine Laser: advances in development and applications

    NASA Astrophysics Data System (ADS)

    Kodymova, Jarmila

    2005-09-01

    Advantageous features of Chemical Oxygen-Iodine Laser (COIL) for laser technologies have increased considerably activities of international COIL communities during past ten years. They have been focused on the advanced concepts of hardware designs of the COIL subsystems, and testing and scaling-up of existing laser facilities. Prospective special applications of COIL technology, both civil and military, have received a significant attention and gained concrete aims. The paper is introduced by a brief description of the COIL operation mechanism and key device subsystems. It deals then with presentation of some investigated advanced concepts of singlet oxygen generators, alternative methods for atomic iodine generation, a mixing and ejector nozzle design to downsize a pressure recovery system, and optical resonators for high power COIL systems. The advanced diagnostics and computational modeling are also mentioned as very useful tools for critical insight into the laser kinetics and fluid dynamics, supporting thus the COIL research. The recent progress in the COIL development moves this laser closer to the application projects that are also briefly presented.

  17. 33.8 Tesla with a YBa2Cu3O7-x Superconducting Test Coil

    NASA Astrophysics Data System (ADS)

    Markiewicz, W. D.; Weijers, H. W.; Noyes, P. D.; Trociewitz, U. P.; Pickard, K. W.; Sheppard, W. R.; Jaroszynski, J. J.; Xu, A.; Larbalestier, D. C.; Hazelton, D. W.

    2010-04-01

    A small coil was made and tested for the purpose of magnet technology development for YBa2Cu3O7-x (YBCO) high field coils. The coil has a winding inner diameter of 24 mm, outer diameter of 36 mm, and length of 46 mm in a pancake wound construction of 5 double pancakes. The YBCO conductor is SuperPower SCS4050 with 2×20 μm of copper stabilizer. The coil was tested in the high field user facility of the NHMFL in a 31 T background field magnet. At this background field, the coil was operated to a current of 325 A and produced a field increment of 2.8 T for a record total field of 33.8 T. The average current density in the windings at full current was very high at 446 A/mm2. The test was complicated by the accumulation of trapped helium gas about the coil due to the diamagnetic effect of helium at high field. Even though the coil operated at elevated temperature during the high field test, the coil performance was limited by mechanical degradation and not a critical current limit.

  18. Optimized Geometry for Superconducting Sensing Coils

    NASA Technical Reports Server (NTRS)

    Eom, Byeong Ho; Pananen, Konstantin; Hahn, Inseob

    2008-01-01

    An optimized geometry has been proposed for superconducting sensing coils that are used in conjunction with superconducting quantum interference devices (SQUIDs) in magnetic resonance imaging (MRI), magnetoencephalography (MEG), and related applications in which magnetic fields of small dipoles are detected. In designing a coil of this type, as in designing other sensing coils, one seeks to maximize the sensitivity of the detector of which the coil is a part, subject to geometric constraints arising from the proximity of other required equipment. In MRI or MEG, the main benefit of maximizing the sensitivity would be to enable minimization of measurement time. In general, to maximize the sensitivity of a detector based on a sensing coil coupled with a SQUID sensor, it is necessary to maximize the magnetic flux enclosed by the sensing coil while minimizing the self-inductance of this coil. Simply making the coil larger may increase its self-inductance and does not necessarily increase sensitivity because it also effectively increases the distance from the sample that contains the source of the signal that one seeks to detect. Additional constraints on the size and shape of the coil and on the distance from the sample arise from the fact that the sample is at room temperature but the coil and the SQUID sensor must be enclosed within a cryogenic shield to maintain superconductivity.

  19. Iterated crowdsourcing dilemma game

    NASA Astrophysics Data System (ADS)

    Oishi, Koji; Cebrian, Manuel; Abeliuk, Andres; Masuda, Naoki

    2014-02-01

    The Internet has enabled the emergence of collective problem solving, also known as crowdsourcing, as a viable option for solving complex tasks. However, the openness of crowdsourcing presents a challenge because solutions obtained by it can be sabotaged, stolen, and manipulated at a low cost for the attacker. We extend a previously proposed crowdsourcing dilemma game to an iterated game to address this question. We enumerate pure evolutionarily stable strategies within the class of so-called reactive strategies, i.e., those depending on the last action of the opponent. Among the 4096 possible reactive strategies, we find 16 strategies each of which is stable in some parameter regions. Repeated encounters of the players can improve social welfare when the damage inflicted by an attack and the cost of attack are both small. Under the current framework, repeated interactions do not really ameliorate the crowdsourcing dilemma in a majority of the parameter space.

  20. Comparison of a single optimized coil and a Helmholtz pair for magnetic nanoparticle hyperthermia.

    PubMed

    Nieskoski, Michael D; Trembly, B Stuart

    2014-06-01

    Magnetic nanoparticles in a tumor can induce therapeutic heating when energized by an alternating magnetic field from a current-carrying coil outside the body. We analyzed a single-turn, air-core coil carrying a filamentary current to quantify the power absorbed by: a) magnetic nanoparticles at depth in tissue and b) superficial tissue in response to induced eddy currents; we defined this quotient as power ratio (PR). Given some limit on the eddy current heating tolerated by an alert patient, maximizing the PR maximizes the power absorbed in the tumor; all else being equal, this increases the thermal dose delivered to the tumor. The mean eddy current heating rate tolerated in four clinical studies we reviewed equaled 12.5 kW/m (3). We differentiated our analytical expression for PR with respect to the radius of the coil to find the value of radius that maximizes PR. Under reasonable simplifying assumptions, the optimal value of coil radius equaled 1.187 times the depth of the nanoparticle target below the body surface. We also derived the PR of two coils surrounding the body configured as a Helmholtz pair. We computed PR for combinations of nanoparticle depths below the surface and axial locations with respect to the coils. At depths less than 4.6 cm, the optimized single coil had a higher PR than that of the Helmholtz pair and furthermore produced less total ohmic heating within the coil. These results were independent of driving frequency, nanoparticle concentration, tissue electrical conductivity, and magnetic nanoparticle heating rate, provided the latter is assumed to be proportional to the product of frequency and the square of the local magnetic field. This paper supports the clinical application of current-carrying coils to deliver efficacious hyperthermia therapy to tumors injected with magnetic nanoparticles. PMID:24691525

  1. Coil motion effects in watt balances: a theoretical check

    NASA Astrophysics Data System (ADS)

    Li, Shisong; Schlamminger, Stephan; Haddad, Darine; Seifert, Frank; Chao, Leon; Pratt, Jon R.

    2016-04-01

    A watt balance is a precision apparatus for the measurement of the Planck constant that has been proposed as a primary method for realizing the unit of mass in a revised International System of Units. In contrast to an ampere balance, which was historically used to realize the unit of current in terms of the kilogram, the watt balance relates electrical and mechanical units through a virtual power measurement and has far greater precision. However, because the virtual power measurement requires the execution of a prescribed motion of a coil in a fixed magnetic field, systematic errors introduced by horizontal and rotational deviations of the coil from its prescribed path will compromise the accuracy. We model these potential errors using an analysis that accounts for the fringing field in the magnet, creating a framework for assessing the impact of this class of errors on the uncertainty of watt balance results.

  2. Development of a pulsed cable test facility for superconducting ohmic heating coils

    SciTech Connect

    Kim, S.H.; Smith, R.P.; Kustom, R.L.; Praeg, W.F.; Krieger, C.I.

    1980-01-01

    This paper describes a Pulsed Cable Test Facility (PCTF) under development at Argonne National Laboratory (ANL). Its essential part is a pulsed superconducting split coil. The inner and outer diameters of the coil will be 45.1 cm and 88.3 cm, respectively, with an adjustable gap between the two halves of the coil. At a peak current of 11 kA, the coil will store an energy of 3.5 MJ and produce a magnetic field of 6.4 T. Using a 7 MW pulsed (2.9 MW rms) power supply, the PCTF coil will produce field change of 6 T/s. With the addition of a solid state switch to the system, dB/dt values of up to 24 T/s can be obtained. Pancake coils, wound with developmental cables, will be placed in the adjustable gap of the PCTF coil and be tested at up to 50 kA furnished by a separate power supply. The PCTF cryogenic facilities include a non-metallic cryostat and a helium liquefier.

  3. Optimum Construction of Heating Coil for Domestic Induction Cooker

    NASA Astrophysics Data System (ADS)

    Sinha, Dola; Bandyopadhyay, Atanu; Sadhu, Pradip Kumar; Pal, Nitai

    2010-10-01

    The design and optimization of the parameters of heating coil is very important for the analytical analysis of high frequency inverter fed induction cooker. Moreover, accurate prediction of high frequency winding loss (i.e., losses due to skin and proximity effects) is necessary as the induction cooker used in power electronics applications. At high frequency current penetration in the induction coil circuit is very difficult for conducting wire due to skin-effect. To eradicate the skin effect heating coil is made up of bundle conductor i.e., litz wire. In this paper inductances and AC resistances of a litz-wire are calculated and optimized by considering the input parameters like wire type, shape, number of strand, number of spiral turn, number of twist per feet of heating coil and operating frequency. A high frequency half bridge series resonant mirror inverter circuit is used in this paper and taking the optimum values of inductance and ac resistance the circuit is simulated through PSPICE simulations. It has been noticed that the results are feasible enough for real implementation.

  4. Considerations of a ship defense with a pulsed COIL

    NASA Astrophysics Data System (ADS)

    Takehisa, K.

    2015-10-01

    Ship defense system with a pulsed COIL (Chemical Oxygen-Iodine Laser) has been considered. One of the greatest threats for battle ships and carriers in warfare are supersonic anti-ship cruise missiles (ASCMs). A countermeasure is considered to be a supersonic RAM (Rolling Airframe Missile) at first. A gun-type CIWS (Close-In Weapon System) should be used as the last line of defense. However since an ASCM can be detected at only 30-50km away due to radar horizon, a speed-of-light weapon is desirable as the first defense especially if the ASCM flies at >Mach 6. Our previous report explained several advantages of a giant pulse from a chemical oxygen laser (COL) to shoot down supersonic aircrafts. Since the first defense has the target distance of ~30km, the use of COIL is better considering its beam having high transmissivity in air. Therefore efficient operation of a giant-pulsed COIL has been investigated with rate-equation simulations. The simulation results indicate that efficient single-pass amplification can be expected. Also a design example of a giant-pulsed COIL MOPA (master oscillator and power amplifier) system has been shown, in which the output energy can be increased without limit.

  5. Design of a superconducting volume coil for magnetic resonance microscopy of the mouse brain

    NASA Astrophysics Data System (ADS)

    Nouls, John C.; Izenson, Michael G.; Greeley, Harold P.; Johnson, G. Allan

    2008-04-01

    We present the design process of a superconducting volume coil for magnetic resonance microscopy of the mouse brain at 9.4 T. The yttrium barium copper oxide coil has been designed through an iterative process of three-dimensional finite-element simulations and validation against room temperature copper coils. Compared to previous designs, the Helmholtz pair provides substantially higher B1 homogeneity over an extended volume of interest sufficiently large to image biologically relevant specimens. A custom-built cryogenic cooling system maintains the superconducting probe at 60 ± 0.1 K. Specimen loading and probe retuning can be carried out interactively with the coil at operating temperature, enabling much higher through-put. The operation of the probe is a routine, consistent procedure. Signal-to-noise ratio in a mouse brain increased by a factor ranging from 1.1 to 2.9 as compared to a room-temperature solenoid coil optimized for mouse brain microscopy. We demonstrate images encoded at 10 × 10 × 20 μm for an entire mouse brain specimen with signal-to-noise ratio of 18 and a total acquisition time of 16.5 h, revealing neuroanatomy unseen at lower resolution. Phantom measurements show an effective spatial resolution better than 20 μm.

  6. Coil Designs for Novel Magnetic Geometries to Cure the Divertor Heat Flux Problem for Reactors

    NASA Astrophysics Data System (ADS)

    Pekker, M.; Valanju, P.; Kotschenreuther, M.; Wiley, J. C.; Strickler, D.

    2004-11-01

    Coil designs are developed for novel magnetic divertor geometries with a second axi-symmetric x-point and flux expansion region along the separatrix. Adjacent posters describe how these lead to spreading of heat flux and the possibility of stable, complete detachment to overcome serious physics and engineering problems in reactors. The principal feasibility issue is creating, with simple coils, additional X-points on the separatrix without extensively deforming the magnetic field in the main plasma. For the spherical tokamak NSTX, we show that adding one or two poloidal coils suffices to create a divergent flux at the divertor, i.e., a new x-point. The currents and forces for the extra coils are small. We also modify ARIES ST design to show reactor feasibility. Optimized coil designs for PEGASUS, ARIES RS/AT, and a modular ITER retrofit are also being developed. For our calculations we used self consistent code FBEQ, which was used to design NSTX. We also use NCSX tools for optimization of designs with competing physics and engineering constraints.

  7. Electromagnetic levitation coil fabrication technique for MSFC containerless processing facilities

    NASA Technical Reports Server (NTRS)

    Ethridge, E. C.; Theiss, J.; Curreri, P. A.; Abbaschian, G. J.

    1983-01-01

    A technique is described for more reproducible fabrication of electromagnetic levitation coils. A split mandrel was developed upon which the coil is wound. After fabrication the mandrel can be disassembled to remove it from the coil. Previously, a full day was required to fabricate a levitation coil and the success rate for a functional coil was only 50 percent. About eight coils may be completed in one day using the technique developed and 95 percent of them are good levitation coils.

  8. The Golgin Family of Coiled-Coil Tethering Proteins

    PubMed Central

    Witkos, Tomasz M.; Lowe, Martin

    2016-01-01

    The golgins are a family of predominantly coiled-coil proteins that are localized to the Golgi apparatus. Golgins are present in all eukaryotes, suggesting an evolutionary conserved function. Golgins are anchored to the Golgi membrane by their carboxy terminus and are predicted to adopt an extended conformation that projects into the surrounding cytoplasm. This arrangement is ideal for the capture or tethering of nearby membranes or cytoskeletal elements. Golgin-mediated tethering is thought to be important for vesicular traffic at the Golgi apparatus, the maintenance of Golgi architecture, as well as the positioning of the Golgi apparatus within cells. In addition to acting as tethers, some golgins can also sequester various factors at the Golgi membrane, allowing for the spatiotemporal regulation of downstream cellular functions. Although it is now established that golgins are membrane and cytoskeleton tethers, the mechanisms underlying tethering remain poorly defined. Moreover, the importance of golgin-mediated tethering in a physiological context remains to be fully explored. This review will describe our current understanding of golgin function, highlighting recent progress that has been made, and goes on to discuss outstanding questions and potential avenues for future research with regard to this family of conserved Golgi-associated proteins. PMID:26793708

  9. Crystal Structure of a Super Leucine Zipper an Extended Two-Stranded Super Long Coiled Coil

    SciTech Connect

    J Diao

    2011-12-31

    Coiled coil is a ubiquitous structural motif in proteins, with two to seven alpha helices coiled together like the strands of a rope, and coiled coil folding and assembly is not completely understood. A GCN4 leucine zipper mutant with four mutations of K3A, D7A, Y17W, and H18N has been designed, and the crystal structure has been determined at 1.6 {angstrom} resolution. The peptide monomer shows a helix trunk with short curved N- and C-termini. In the crystal, two monomers cross in 35{sup o} and form an X-shaped dimer, and each X-shaped dimer is welded into the next one through sticky hydrophobic ends, thus forming an extended two-stranded, parallel, super long coiled coil rather than a discrete, two-helix coiled coil of the wild-type GCN4 leucine zipper. Leucine residues appear at every seventh position in the super long coiled coil, suggesting that it is an extended super leucine zipper. Compared to the wild-type leucine zipper, the N-terminus of the mutant has a dramatic conformational change and the C-terminus has one more residue Glu 32 determined. The mutant X-shaped dimer has a large crossing angle of 35{sup o} instead of 18{sup o} in the wild-type dimer. The results show a novel assembly mode and oligomeric state of coiled coil, and demonstrate that mutations may affect folding and assembly of the overall coiled coil. Analysis of the formation mechanism of the super long coiled coil may help understand and design self-assembling protein fibers.

  10. Critical evaluation of in silico methods for prediction of coiled-coil domains in proteins.

    PubMed

    Li, Chen; Ching Han Chang, Catherine; Nagel, Jeremy; Porebski, Benjamin T; Hayashida, Morihiro; Akutsu, Tatsuya; Song, Jiangning; Buckle, Ashley M

    2016-03-01

    Coiled-coils refer to a bundle of helices coiled together like strands of a rope. It has been estimated that nearly 3% of protein-encoding regions of genes harbour coiled-coil domains (CCDs). Experimental studies have confirmed that CCDs play a fundamental role in subcellular infrastructure and controlling trafficking of eukaryotic cells. Given the importance of coiled-coils, multiple bioinformatics tools have been developed to facilitate the systematic and high-throughput prediction of CCDs in proteins. In this article, we review and compare 12 sequence-based bioinformatics approaches and tools for coiled-coil prediction. These approaches can be categorized into two classes: coiled-coil detection and coiled-coil oligomeric state prediction. We evaluated and compared these methods in terms of their input/output, algorithm, prediction performance, validation methods and software utility. All the independent testing data sets are available at http://lightning.med.monash.edu/coiledcoil/. In addition, we conducted a case study of nine human polyglutamine (PolyQ) disease-related proteins and predicted CCDs and oligomeric states using various predictors. Prediction results for CCDs were highly variable among different predictors. Only two peptides from two proteins were confirmed to be CCDs by majority voting. Both domains were predicted to form dimeric coiled-coils using oligomeric state prediction. We anticipate that this comprehensive analysis will be an insightful resource for structural biologists with limited prior experience in bioinformatics tools, and for bioinformaticians who are interested in designing novel approaches for coiled-coil and its oligomeric state prediction. PMID:26177815

  11. Optimum coil insertion speed of various coils in brain aneurysm embolization in vitro.

    PubMed

    Konishi, Yoshifumi; Takeuchi, Masataka; Fukasaku, Kazuaki

    2016-10-01

    A coil must comprise material with shape memory to perform optimal coil embolization. To achieve this, the alloy characteristics of the coil (hardness, shape, and thickness) must be understood. In this experiment, a catheter was fixed in the bright position and the movement of the coil was observed under a constant rate of insertion; the optimal insertion rate during clinical use was investigated. The first coil insertion speed was evaluated using simulated aneurysms in an in vivo arterial model. The results showed that the insertion force relates to the deployment shape of the coil, that the feedback through the force indicator using sound is very effective, and that the recorder is useful for analysis of coil embolization. The inserted coils during aneurysm embolization were able to wind uniformly within the aneurysm due to a variety of factors (guiding or micro-catheter position and kick-back phenomenon such as delivery wire). Optimal speed is achieved with proper coil design, which allows the coil to be inserted into the aneurysm. The shape and size of the aneurysm can help determine the necessary size and design of the coil that should be used during the optimal speed range. Aneurysm wall and coil characteristics are considered, along with the friction state of the coil (hardness, shape, and thickness), leading to improvements in safety during the insertion procedure at optimum speed. PMID:27353635

  12. Optimum coil insertion speed of various coils in brain aneurysm embolization in vitro.

    PubMed

    Konishi, Yoshifumi; Takeuchi, Masataka; Fukasaku, Kazuaki

    2016-10-01

    A coil must comprise material with shape memory to perform optimal coil embolization. To achieve this, the alloy characteristics of the coil (hardness, shape, and thickness) must be understood. In this experiment, a catheter was fixed in the bright position and the movement of the coil was observed under a constant rate of insertion; the optimal insertion rate during clinical use was investigated. The first coil insertion speed was evaluated using simulated aneurysms in an in vivo arterial model. The results showed that the insertion force relates to the deployment shape of the coil, that the feedback through the force indicator using sound is very effective, and that the recorder is useful for analysis of coil embolization. The inserted coils during aneurysm embolization were able to wind uniformly within the aneurysm due to a variety of factors (guiding or micro-catheter position and kick-back phenomenon such as delivery wire). Optimal speed is achieved with proper coil design, which allows the coil to be inserted into the aneurysm. The shape and size of the aneurysm can help determine the necessary size and design of the coil that should be used during the optimal speed range. Aneurysm wall and coil characteristics are considered, along with the friction state of the coil (hardness, shape, and thickness), leading to improvements in safety during the insertion procedure at optimum speed.

  13. The Cryostat and Subsystems Development at ITER

    NASA Astrophysics Data System (ADS)

    Sekachev, Igor; Meekins, Michael; Sborchia, Carlo; Vitupier, Guillaume; Xie, Han; Zhou, Caipin

    ITER is a large experimental tokamak being built to research fusion power. The ITER cryostat is a multifunctional system which provides vacuum insulation for the superconducting magnets operating at 4.5 K and for the thermal shield operating at 80 K. It also serves as a structural support for the tokamak and provides access ways and corridors to the vacuum vessel for diagnostic lines of sight, additional heating beams and the deployment of remote handling equipment. The cryostat has feed-through penetrations for all the equipment connecting elements of systems outside the cryostat to the corresponding elements inside the cryostat. The cryostat is a vacuum containment vessel having a very large volume of ∼16000 m3 designed to be evacuated to a base pressure of 10-4 Pa. Design details of the cryostat and associated systems, including Torus Cryopump Housing (TCPH), are discussed. Status report of the cryostat developments is presented.

  14. Note: High turn density magnetic coils with improved low pressure water cooling for use in atom optics

    SciTech Connect

    McKay Parry, Nicholas Neely, Tyler; Carey, Thomas; Bell, Thomas; Rubinsztein-Dunlop, Halina; Baker, Mark

    2014-08-15

    We describe a magnetic coil design utilizing concentrically wound electro-magnetic insulating (EMI) foil (25.4 μm Kapton backing and 127 μm thick layers). The magnetic coils are easily configurable for different coil sizes, while providing large surfaces for low-pressure (0.12 bar) water cooling. The coils have turn densities of ∼5 mm{sup −1} and achieve a maximum of 377 G at 2.1 kW driving power, measured at a distance 37.9 mm from the axial center of the coil. The coils achieve a steady-state temperature increase of 36.7°C/kW.

  15. Note: High turn density magnetic coils with improved low pressure water cooling for use in atom optics.

    PubMed

    McKay Parry, Nicholas; Baker, Mark; Neely, Tyler; Carey, Thomas; Bell, Thomas; Rubinsztein-Dunlop, Halina

    2014-08-01

    We describe a magnetic coil design utilizing concentrically wound electro-magnetic insulating (EMI) foil (25.4 μm Kapton backing and 127 μm thick layers). The magnetic coils are easily configurable for different coil sizes, while providing large surfaces for low-pressure (0.12 bar) water cooling. The coils have turn densities of ~5 mm(-1) and achieve a maximum of 377 G at 2.1 kW driving power, measured at a distance 37.9 mm from the axial center of the coil. The coils achieve a steady-state temperature increase of 36.7°C/kW. PMID:25173328

  16. Assessment of possible failure modes and non-destructive examination of the ITER pre-compression rings

    NASA Astrophysics Data System (ADS)

    Knaster, J.; Evans, D.; Rajainmaki, H.

    2012-06-01

    The pre-compression rings (PCRs) for the International Thermonuclear Experimental Reactor (ITER) represent one of the largest and most highly stressed composite structures ever designed for long term operation at 4K. Three rings, each 5m in diameter and 337 × 288 mm in cross-section, will be installed at the top and bottom of the eighteen "D" shaped Toroidal Field (TF) coils to apply a total centripetal load of 70 MN per TF coil. The interaction of the 68 kA conductor current circulating in the coil (for a total of 9.1MA) with the required magnetic field to confine the plasma during operation will result in Lorentz forces that build in-plane and out-of-plane loads. The PCRs are essential to keep the stresses below the acceptable level for the ITER magnets structural materials.

  17. Progress on the Design of the Coupling coils for MICE andMUCOOL

    SciTech Connect

    Green, M.A.; Li, D.; Virostek, Steve P.; Wang, L.; Wu, H.; Li,L.K.; Li, S.Y.; Xu, F.Y.; Guo, X.L.; Liu, C.S.; Han, G.; Liu, X.K.; Jia,L.X.

    2007-06-20

    The Muon Ionization Cooling Experiment (MICE) [1]willdemonstrate ionization cooling in a short section of a realistic coolingchannel using a muon beam at Rutherford Appleton Laboratory (RAL) in theUK. The MICE RF and Coupling Coil (RFCC) Module consists of asuperconducting solenoid mounted around four normal conducting 201.25-MHzRF cavities. The coil package that surrounds the RF cavities is to bemounted in a 1.4 m diameter vacuum vessel. The coupling coil confines thebeam in the RFCC module within the radius of the RF cavity beam windows.Each coupling magnet will be powered by a 300 A, 10 V power supply. Themaximum design longitudinal force that will be carried by the cold masssupport system is 0.5 MN. The detailed design and analysis of thecoupling magnet has been completed by ICST. The primary magnetic andmechanical design features of the coils are presented in thispaper.

  18. The structure of the GemC1 coiled coil and its interaction with the Geminin family of coiled-coil proteins

    PubMed Central

    Caillat, Christophe; Fish, Alexander; Pefani, Dafni-Eleftheria; Taraviras, Stavros; Lygerou, Zoi; Perrakis, Anastassis

    2015-01-01

    GemC1, together with Idas and Geminin, an important regulator of DNA-replication licensing and differentiation decisions, constitute a superfamily sharing a homologous central coiled-coil domain. To better understand this family of proteins, the crystal structure of a GemC1 coiled-coil domain variant engineered for better solubility was determined to 2.2 Å resolution. GemC1 shows a less typical coiled coil compared with the Geminin homodimer and the Geminin–Idas heterodimer structures. It is also shown that both in vitro and in cells GemC1 interacts with Geminin through its coiled-coil domain, forming a heterodimer that is more stable that the GemC1 homodimer. Comparative analysis of the thermal stability of all of the possible superfamily complexes, using circular dichroism to follow the unfolding of the entire helix of the coiled coil, or intrinsic tryptophan fluorescence of a unique conserved N-terminal tryptophan, shows that the unfolding of the coiled coil is likely to take place from the C-terminus towards the N-terminus. It is also shown that homodimers show a single-state unfolding, while heterodimers show a two-state unfolding, suggesting that the dimer first falls apart and the helices then unfold according to the stability of each protein. The findings argue that Geminin-family members form homodimers and heterodimers between them, and this ability is likely to be important for modulating their function in cycling and differentiating cells. PMID:26527144

  19. Accessing Three-Dimensional Crystals with Incorporated Guests through Metal-Directed Coiled-Coil Peptide Assembly.

    PubMed

    Nepal, Manish; Sheedlo, Michael J; Das, Chittaranjan; Chmielewski, Jean

    2016-08-31

    Obtaining three-dimensional (3D) protein and peptide crystals on demand requires a precisely orchestrated hierarchical assembly of biopolymer building blocks. In this work, we disclose a metal-ion-mediated strategy to assemble trimeric coiled-coil peptides in a head-to-tail fashion into linear strands with interstrand interactions. This design led to hexagonal 3D peptide crystal formation within 30 min in the presence of divalent metal ions. The crystal morphology could be controlled by varying the metal ion/peptide ratio, resulting in hexagonal discs to rods. Diffraction studies elucidated the head-to-tail arrangement of the coiled-coil linear strands and their hexagonal, antiparallel packing within the crystal. Unsatisfied ligands at the hexagonal ends of the crystals were harnessed as a powerful means to direct His-tagged fluorophores to distinct locations within the crystals. Overall, the designed hierarchical assembly provides a facile means to obtain 3D peptide crystals and incorporate His-tag-based cargoes and may have potential use in drug delivery and sensor design. PMID:27500907

  20. Transport Vesicle Tethering at the Trans Golgi Network: Coiled Coil Proteins in Action.

    PubMed

    Cheung, Pak-Yan P; Pfeffer, Suzanne R

    2016-01-01

    The Golgi complex is decorated with so-called Golgin proteins that share a common feature: a large proportion of their amino acid sequences are predicted to form coiled-coil structures. The possible presence of extensive coiled coils implies that these proteins are highly elongated molecules that can extend a significant distance from the Golgi surface. This property would help them to capture or trap inbound transport vesicles and to tether Golgi mini-stacks together. This review will summarize our current understanding of coiled coil tethers that are needed for the receipt of transport vesicles at the trans Golgi network (TGN). How do long tethering proteins actually catch vesicles? Golgi-associated, coiled coil tethers contain numerous binding sites for small GTPases, SNARE proteins, and vesicle coat proteins. How are these interactions coordinated and are any or all of them important for the tethering process? Progress toward understanding these questions and remaining, unresolved mysteries will be discussed.

  1. Helical axis stellarator with noninterlocking planar coils

    DOEpatents

    Reiman, Allan; Boozer, Allen H.

    1987-01-01

    A helical axis stellarator using only noninterlocking planar, non-circular coils, generates magnetic fields having a magnetic well and large rotational transform with resultant large equilibrium beta.

  2. Defect-Free Carbon Nanotube Coils.

    PubMed

    Shadmi, Nitzan; Kremen, Anna; Frenkel, Yiftach; Lapin, Zachary J; Machado, Leonardo D; Legoas, Sergio B; Bitton, Ora; Rechav, Katya; Popovitz-Biro, Ronit; Galvão, Douglas S; Jorio, Ado; Novotny, Lukas; Kalisky, Beena; Joselevich, Ernesto

    2016-04-13

    Carbon nanotubes are promising building blocks for various nanoelectronic components. A highly desirable geometry for such applications is a coil. However, coiled nanotube structures reported so far were inherently defective or had no free ends accessible for contacting. Here we demonstrate the spontaneous self-coiling of single-wall carbon nanotubes into defect-free coils of up to more than 70 turns with identical diameter and chirality, and free ends. We characterize the structure, formation mechanism, and electrical properties of these coils by different microscopies, molecular dynamics simulations, Raman spectroscopy, and electrical and magnetic measurements. The coils are highly conductive, as expected for defect-free carbon nanotubes, but adjacent nanotube segments in the coil are more highly coupled than in regular bundles of single-wall carbon nanotubes, owing to their perfect crystal momentum matching, which enables tunneling between the turns. Although this behavior does not yet enable the performance of these nanotube coils as inductive devices, it does point a clear path for their realization. Hence, this study represents a major step toward the production of many different nanotube coil devices, including inductors, electromagnets, transformers, and dynamos.

  3. Defect-Free Carbon Nanotube Coils.

    PubMed

    Shadmi, Nitzan; Kremen, Anna; Frenkel, Yiftach; Lapin, Zachary J; Machado, Leonardo D; Legoas, Sergio B; Bitton, Ora; Rechav, Katya; Popovitz-Biro, Ronit; Galvão, Douglas S; Jorio, Ado; Novotny, Lukas; Kalisky, Beena; Joselevich, Ernesto

    2016-04-13

    Carbon nanotubes are promising building blocks for various nanoelectronic components. A highly desirable geometry for such applications is a coil. However, coiled nanotube structures reported so far were inherently defective or had no free ends accessible for contacting. Here we demonstrate the spontaneous self-coiling of single-wall carbon nanotubes into defect-free coils of up to more than 70 turns with identical diameter and chirality, and free ends. We characterize the structure, formation mechanism, and electrical properties of these coils by different microscopies, molecular dynamics simulations, Raman spectroscopy, and electrical and magnetic measurements. The coils are highly conductive, as expected for defect-free carbon nanotubes, but adjacent nanotube segments in the coil are more highly coupled than in regular bundles of single-wall carbon nanotubes, owing to their perfect crystal momentum matching, which enables tunneling between the turns. Although this behavior does not yet enable the performance of these nanotube coils as inductive devices, it does point a clear path for their realization. Hence, this study represents a major step toward the production of many different nanotube coil devices, including inductors, electromagnets, transformers, and dynamos. PMID:26708150

  4. Report of the SSC workshop on distributed multipole correction coils. Task force report

    SciTech Connect

    Sah, R.

    1988-01-01

    The SSC Workshop on Distributed Multipole Correction Coils was held at Brookhaven National Laboratory on October 13 and 14, 1987. This Workshop was organized by the SSC Central Design Group, and its purpose was to discuss the present status of specifications, designs, and R&D plans for distributed, actively-powered multipole correction coils for the SSC. The Workshop was organized into four consecutive sessions to discuss the following topics: requirements for distributed correction coils, distributed connection coil designs, materials issues, and plans for future R&D. The following conclusions were drawn from the workshop: Accelerator physics considerations indicate that distributed multipole correction coils represent a feasible and flexible method to correct magnetic field errors in the SSC. Considerable progress has been made by Brookhaven National Laboratory in collaboration with industry to develop a possible fabrication technique for distributed correction coils. This technique consists of imbedding superconducting wire in a flexible plastic substrate. Its feasibility for the SSC still needs to be demonstrated. BNL has presented a preliminary plan for the necessary R&D. A successful technique has been developed to manufacture distributed correction coils for HERA. The coil performance is excellent. As yet, no plan has been proposed to study this type of correction coil for the SSC. The results from an experiment to study radiation damage to organic materials, although still preliminary, am providing guidance in selecting the most radiation resistant materials to use in correction coils. The test samples in this experiment were subjected to much larger radiation doses than expected at the SSC. Considerable information on radiation damage is available in the literature.

  5. Simulation and optimization of the magnetic field in an electroplated copper micro-coil

    NASA Astrophysics Data System (ADS)

    Matar, Maher; Al-Halhouli, Alaaldeen T.; Büttgenbach, Stephanus; Dietzel, Andreas H.

    2013-05-01

    This work aims at simulating and optimizing the magnetic field intensity in different electroplated copper micro-coil designs that can be integrated in a recently developed electromagnetic micro-pump. The results of this study will be used in fabricating new optimized micro-coil designs that may enhance the performance of the developed synchronous micro-pump (i.e., the maximum back pressures and flow rates). The synchronous micro-pump concept depends on managing the movement of two magnets in an annular fluidic channel. Magnet rotation is achieved by sequentially activating a set of planar micro-coils to repel or attract the first magnet (traveling magnet) through the channel, while the second one is anchored between the inlet and the outlet ports. At the end of each pumping cycle, the magnets exchange their anchored and traveling functions. To achieve the maximum back pressure and flow rate (highest performance) in such micro-pump, higher magnetic fields without exceeding the material temperature limitation are required. The stronger the magnetic fields that can be generated, the higher the hydraulic power that can the pump deliver. This study presents extensive numerical simulations using the commercial software package COMSOL and presents also optimizations for the effect of the main micro-coil parameters on the generated magnetic field: coil wire width and height, the coil turns offset distance, the effect of including an iron core inside the coil area, and the number of coil turns. The main analyzed results are: the normal magnetic flux contours at the top (upper) surface of the coil - where the permanent magnets rotate in the micro-pump channel -, the distribution of the magnetic field streams and the area averaging of the magnetic field intensity all over the micro-coil sector.

  6. Predictive study of current sharing temperature test in the Toroidal Field Model Coil without LCT coil using the M&M code

    NASA Astrophysics Data System (ADS)

    Savoldi, L.; Zanino, R.

    2000-08-01

    The Toroidal Field Model Coil (TFMC) will be tested next year at Forschungszentrum Karlsruhe, Germany, in the frame of the International Thermonuclear Experimental Reactor (ITER). The TFMC is pancake-wound on radial plates using 10 Nb 3Sn two-channel cable-in-conduit conductors, jointed on the inner- and outer-side of the coil. The drivers for the test of current sharing temperature ( Tcs) are the resistive heaters located on the inlet plumbing to each conductor (DP1.1, DP1.2) of the first double pancake (DP1). Since all available sensors are outside the coil, Tcs in the conductor must be measured indirectly, which requires sophisticated analysis tools because of the complexity of the system. In the present work we use the recently developed Multi-conductor Mithrandir (M&M) code. The main aim of the paper is of assessing computationally possible scenarios of normal zone initiation in the high field region of the conductor, without quench propagation out of the inlet joint, in the test configuration without LCT coil.

  7. Magnetic Control of Locked Modes in Present Devices and ITER

    NASA Astrophysics Data System (ADS)

    Volpe, F. A.; Sabbagh, S.; Sweeney, R.; Hender, T.; Kirk, A.; La Haye, R. J.; Strait, E. J.; Ding, Y. H.; Rao, B.; Fietz, S.; Maraschek, M.; Frassinetti, L.; in, Y.; Jeon, Y.; Sakakihara, S.

    2014-10-01

    The toroidal phase of non-rotating (``locked'') neoclassical tearing modes was controlled in several devices by means of applied magnetic perturbations. Evidence is presented from various tokamaks (ASDEX Upgrade, DIII-D, JET, J-TEXT, KSTAR), spherical tori (MAST, NSTX) and a reversed field pinch (EXTRAP-T2R). Furthermore, the phase of interchange modes was controlled in the LHD helical device. These results share a common interpretation in terms of torques acting on the mode. Based on this interpretation, it is predicted that control-coil currents will be sufficient to control the phase of locking in ITER. This will be possible both with the internal coils and with the external error-field-correction coils, and might have promising consequences for disruption avoidance (by aiding the electron cyclotron current drive stabilization of locked modes), as well as for spatially distributing heat loads during disruptions. This work was supported in part by the US Department of Energy under DE-SC0008520, DE-FC-02-04ER54698 and DE-AC02-09CH11466.

  8. An active homopolar magnetic bearing with high temperature superconductor (HTS) coils and ferromagnetic cores

    NASA Technical Reports Server (NTRS)

    Brown, G. V.; Dirusso, E.; Provenza, A. J.

    1995-01-01

    A proof-of-feasibility demonstration showed that high temperature superconductor (HTS) coils can be used in a high-load, active magnetic bearing in liquid nitrogen. A homopolar radial bearing with commercially wound HTS (Bi 2223) bias and control coils produced over 200 lb (890 N) radial load capacity (measured non-rotating) and supported a shaft to 14000 rpm. The goal was to show that HTS coils can operate stably with ferromagnetic cores in a feedback controlled system at a current density similar to that in Cu in liquid nitrogen. Design compromises permitted use of circular coils with rectangular cross section. Conductor improvements will eventually permit coil shape optimization, higher current density and higher bearing load capacity. The bias coil, wound with non-twisted, multifilament HTS conductor, required negligible power to carry its direct current. The control coils were wound with monofilament HTS sheathed in Ag. These dissipated negligible power for direct current (i.e. for steady radial load components). When an alternating current (AC) was added, the AC component dissipated power which increased rapidly with frequency and quadratically with AC amplitude. In fact at frequencies above about 2 hz, the effective resistance of the control coil conductor actually exceeds that of the silver which is in electrical parallel with the oxide superconductor. This is at least qualitatively understandable in the context of a Bean-type model of flux and current penetration into a Type II superconductor. Fortunately the dynamic currents required for bearing stability are of small amplitude. These results show that while twisted multifilament conductor is not needed for stable levitation, twisted multifilaments will be required to reduce control power for sizable dynamic loads, such as those due to unbalance.

  9. A Non-perturbing Probe of Coiled Coil Formation Based on Electron Transfer Mediated Fluorescence Quenching.

    PubMed

    Watson, Matthew D; Peran, Ivan; Raleigh, Daniel P

    2016-07-01

    Coiled coils are abundant in nature, occurring in ∼3% of proteins across sequenced genomes, and are found in proteins ranging from transcription factors to structural proteins. The motif continues to be an important model system for understanding protein-protein interactions and is finding increased use in bioinspired materials and synthetic biology. Knowledge of the thermodynamics of self-assembly, particularly the dissociation constant KD, is essential for the application of designed coiled coils and for understanding the in vivo specificity of natural coiled coils. Standard methods for measuring KD typically rely on concentration dependent circular dichroism (CD). Fluorescence methods are an attractive alternative; however Trp is rarely found in an interior position of a coiled coil, and appending unnatural fluorophores can perturb the system. We demonstrate a simple, non-perturbing method to monitor coiled coil formation using p-cyanophenylalanine (FCN) and selenomethionine (MSe), the Se analogue of Met. FCN fluorescence can be selectively excited and is effectively quenched by electron transfer with MSe. Both FCN and MSe represent minimally perturbing substitutions in coiled coils. MSe quenching of FCN fluorescence is shown to offer a non-perturbing method for following coiled coil formation and for accurately determining dissociation constants. The method is validated using a designed heterodimeric coiled coil. The KD deduced by fluorescence monitored titration is in excellent agreement with the value deduced from concentration dependent CD measurements to within the uncertainty of the measurement. However, the fluorescence approach requires less protein, is less time-consuming, can be applied to lower concentrations and could be applied to high throughput screens. PMID:27258904

  10. Compact stellarators with modular coils

    PubMed Central

    Garabedian, P. R.

    2000-01-01

    Compact stellarator designs with modular coils and only two or three field periods are now available; these designs have both good stability and quasiaxial symmetry providing adequate transport for a magnetic fusion reactor. If the bootstrap current assumes theoretically predicted values a three field period configuration is optimal, but if that net current turns out to be lower, a device with two periods and just 12 modular coils might be better. There are also attractive designs with quasihelical symmetry and four or five periods whose properties depend less on the bootstrap current. Good performance requires that there be a satisfactory magnetic well in the vacuum field, which is a property lacking in a stellarator-tokamak hybrid that has been proposed for a proof of principle experiment. In this paper, we present an analysis of stability for these configurations that is based on a mountain pass theorem asserting that, if two solutions of the problem of magnetohydrodynamic equilibrium can be found, then there has to be an unstable solution. We compare results of our theory of equilibrium, stability, and transport with recently announced measurements from the large LHD experiment in Japan. PMID:10899993

  11. Regulation of Stat1 protein expression by phenylalanine 172 in the coiled-coil domain

    SciTech Connect

    Hoshino, Akemi; Fleur, Shella Saint; Fujii, Hodaka . E-mail: hodaka@med.nyu.edu

    2006-08-04

    Stat1 plays an essential role in signal transduction and gene expression of various cytokines including interferons (IFNs). Although the mechanism of cytokine-induced activation of Stat1 and transcriptional regulation of Stat1 gene expression have been established, post-transcriptional regulation of Stat1 protein expression is not fully understood. Here, we report identification of a mutant of Stat1 that has decreased expression levels by using inducible translocation trap (ITT), a reporter gene-based detection system of nuclear translocation. The substitution of serine for phenylalanine 172 (F172S) in the coiled-coil domain causes marked decrease in Stat1 protein expression in various cell lines without decreasing its mRNA levels. Our results suggest that the decrease is caused by translational/post-translational mechanisms independent of proteasome machinery. These results suggest a novel potential mechanism of determination of specificity of Stat proteins and showed that the ITT system is a powerful technique to identify mutants of nuclear translocating signal transducers.

  12. 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.

  13. Accommodation of structural rearrangements in the huntingtin-interacting protein 1 coiled-coil domain

    SciTech Connect

    Wilbur, Jeremy D.; Hwang, Peter K.; Brodsky, Frances M.; Fletterick, Robert J.

    2010-03-01

    Variable packing interaction related to the conformational flexibility within the huntingtin-interacting protein 1 coiled coil domain. Huntingtin-interacting protein 1 (HIP1) is an important link between the actin cytoskeleton and clathrin-mediated endocytosis machinery. HIP1 has also been implicated in the pathogenesis of Huntington’s disease. The binding of HIP1 to actin is regulated through an interaction with clathrin light chain. Clathrin light chain binds to a flexible coiled-coil domain in HIP1 and induces a compact state that is refractory to actin binding. To understand the mechanism of this conformational regulation, a high-resolution crystal structure of a stable fragment from the HIP1 coiled-coil domain was determined. The flexibility of the HIP1 coiled-coil region was evident from its variation from a previously determined structure of a similar region. A hydrogen-bond network and changes in coiled-coil monomer interaction suggest that the HIP1 coiled-coil domain is uniquely suited to allow conformational flexibility.

  14. Natural templates for coiled-coil biomaterials from praying mantis egg cases.

    PubMed

    Walker, Andrew A; Weisman, Sarah; Kameda, Tsunenori; Sutherland, Tara D

    2012-12-10

    Whereas there is growing interest in producing biomaterials containing coiled-coils, relatively few studies have made use of naturally occurring fibrous proteins. In this study, we have characterized fibrous proteins used by mother praying mantises to produce an extensive covering for their eggs called an ootheca and demonstrate the production of artificial ootheca using recombinantly produced proteins. Examination of natural oothecae by infrared spectroscopy and solid-state nuclear magnetic resonance revealed the material to consist of proteins organized predominately as coiled-coils. Two structural proteins, Mantis Fibroin 1 and Mantis Fibroin 2, were identified in ootheca from each of three species. Between species, the primary sequences of both proteins had diverged considerably, but other features were tightly conserved, including low molecular weight, high abundance of Ala, Glu, Lys, and Ser, and a triblock-like architecture with extensive central coiled-coil domain. Mantis fibroin hydrophobic cores had an unusual composition containing high levels of alanine and aromatic residues. Recombinantly produced mantis fibroins folded into coiled-coils in solution and could be fabricated into solid materials with high coiled-coil content. The structural features of mantis fibroins and their straightforward recombinant production make them promising templates for the production of coiled-coil biomimetics materials. PMID:23137042

  15. Stabilization of microgrid with intermittent renewable energy sources by SMES with optimal coil size

    NASA Astrophysics Data System (ADS)

    Saejia, M.; Ngamroo, I.

    2011-11-01

    It is well known that the superconducting coil is the vital part of a superconducting magnetic energy storage (SMES) unit. This paper deals with the power controller design of a SMES unit with an optimal coil size for stabilization of an isolated microgrid. The study microgrid consists of renewable energy sources with intermittent power outputs i.e., wind and photovoltaic. Since power generations from such renewable sources are unpredictable and variable, these result in power fluctuations in a microgrid. To stabilize power fluctuations, a SMES unit with a fast control of active and reactive power can be applied. The structure of a power controller is the practical proportional-integral (PI). Based on the minimization of the variance of power fluctuations from renewable sources as well as the initial stored energy of SMES, the optimal PI parameters and coil size are automatically and simultaneously tuned by a particle swarm optimization. Simulation studies show that the proposed SMES controller with an optimal coil size is able to effectively alleviate power fluctuations under various power patterns from intermittent renewable sources.

  16. ITER Diagnostic First Wal

    SciTech Connect

    G. Douglas Loesser, et. al.

    2012-09-21

    The ITER Diagnostic Division is responsible for designing and procuring the First Wall Blankets that are mounted on the vacuum vessel port plugs at both the upper and equatorial levels This paper will discuss the effects of the diagnostic aperture shape and configuration on the coolant circuit design. The DFW design is driven in large part by the need to conform the coolant arrangement to a wide variety of diagnostic apertures combined with the more severe heating conditions at the surface facing the plasma, the first wall. At the first wall, a radiant heat flux of 35W/cm2 combines with approximate peak volumetric heating rates of 8W/cm3 (equatorial ports) and 5W/cm3 (upper ports). Here at the FW, a fast thermal response is desirable and leads to a thin element between the heat flux and coolant. This requirement is opposed by the wish for a thicker FW element to accommodate surface erosion and other off-normal plasma events.

  17. Mode conversion in ITER

    NASA Astrophysics Data System (ADS)

    Jaeger, E. F.; Berry, L. A.; Myra, J. R.

    2006-10-01

    Fast magnetosonic waves in the ion cyclotron range of frequencies (ICRF) can convert to much shorter wavelength modes such as ion Bernstein waves (IBW) and ion cyclotron waves (ICW) [1]. These modes are potentially useful for plasma control through the generation of localized currents and sheared flows. As part of the SciDAC Center for Simulation of Wave-Plasma Interactions project, the AORSA global-wave solver [2] has been ported to the new, dual-core Cray XT-3 (Jaguar) at ORNL where it demonstrates excellent scaling with the number of processors. Preliminary calculations using 4096 processors have allowed the first full-wave simulations of mode conversion in ITER. Mode conversion from the fast wave to the ICW is observed in mixtures of deuterium, tritium and helium3 at 53 MHz. The resulting flow velocity and electric field shear will be calculated. [1] F.W. Perkins, Nucl. Fusion 17, 1197 (1977). [2] E.F. Jaeger, L.A. Berry, J.R. Myra, et al., Phys. Rev. Lett. 90, 195001-1 (2003).

  18. Wind turbine generators using superconducting coils and bulks

    NASA Astrophysics Data System (ADS)

    Ohsaki, H.; Terao, Y.; Sekino, M.

    2010-06-01

    Wind power generation has been expected as a promising clean energy source in the world. Recently, generation capacity produced by wind power generators has been growing with increasing size of windmills. However, huge nacelles result in extreme load for towers supporting them. We have focused on a wind power generator using superconducting wires and superconducting bulks to solve the problem. Large currents may flow through superconducting wires with zero DC resistance. Superconducting bulks are magnetic shielding materials. These enable reduction of size and weight of nacelles. In addition, large generators using these materials can generate an output power of 10 MW with very large power densities. This paper describes calculation of generated magnetic field and power generation characteristics using three-dimensional finite element method (FEM) analysis of the generators using high temperature superconducting coils and bulks.

  19. An active magnetic bearing with high T(sub c) superconducting coils and ferromagnetic cores

    NASA Technical Reports Server (NTRS)

    Brown, G. V.; Dirusso, E.; Provenza, A. J.

    1995-01-01

    A proof-of-feasibility demonstration showed that high-T(sub c) superconductor (HTS) coils can be used in a high-load, active magnetic bearing in LN2. A homopolar radial bearing with commercially wound HTS (Bi 2223) bias and control coils produced over 890 N (200 lb) radial load capacity (measured non-rotatings) and supported a shaft to 14,000 rpm. The goal was to show that HTS coils can operate stably with ferromagnetic cores in a feedback controlled system at a current density similar to that for Cu in LN2. The bias coil, wound with non-twisted, multifilament HTS conductor, dissipated negligible power for its direct current. The control coils, wound with monofilament HTS sheathed in Ag, dissipated negligible power for direct current. AC losses increased rapidly with frequency and quadratically with AC amplitude. Above about 2 Hz, the effective resistance of the control coils exceeds that of the silver which is in electrical parallel with the oxide superconductor. These results show that twisted multifilament conductor is not needed for stable levitation but may be desired to reduce control power for sizable dynamic loads.

  20. Passive radiative cooling of a HTS coil for attitude orbit control in micro-spacecraft

    NASA Astrophysics Data System (ADS)

    Inamori, Takaya; Ozaki, Naoya; Saisutjarit, Phongsatorn; Ohsaki, Hiroyuki

    2015-02-01

    This paper proposes a novel radiative cooling system for a high temperature superconducting (HTS) coil for an attitude orbit control system in nano- and micro-spacecraft missions. These days, nano-spacecraft (1-10 kg) and micro-spacecraft (10-100 kg) provide space access to a broader range of spacecraft developers and attract interest as space development applications. In planetary and high earth orbits, most previous standard-size spacecraft used thrusters for their attitude and orbit control, which are not available for nano- and micro-spacecraft missions because of the strict power consumption, space, and weight constraints. This paper considers orbit and attitude control methods that use a superconducting coil, which interacts with on-orbit space plasmas and creates a propulsion force. Because these spacecraft cannot use an active cooling system for the superconducting coil because of their mass and power consumption constraints, this paper proposes the utilization of a passive radiative cooling system, in which the superconducting coil is thermally connected to the 3 K cosmic background radiation of deep space, insulated from the heat generation using magnetic holders, and shielded from the sun. With this proposed cooling system, the HTS coil is cooled to 60 K in interplanetary orbits. Because the system does not use refrigerators for its cooling system, the spacecraft can achieve an HTS coil with low power consumption, small mass, and low cost.

  1. Development of ITER 15 MA ELMy H-mode Inductive Scenario

    SciTech Connect

    Kessel, C. E.; Campbell, D.; Gribov, Y.; Saibene, G.; Ambrosino, G.; Casper, T.; Cavinato, M.; Fujieda, H.; Hawryluk, R.; Horton, L. D.; Kavin, A.; Kharyrutdinov, R.; Koechl, F.; Leuer, J.; Loarte, A.; Lomas, P. J.; Luce, T.; Lukash, V.; Mattei, M.; Nunes, I.; Parail, V.; Polevoi, A.; Portone, A.; Sartori, R.; Sips, A. C.C.; Thomas, P. R.; Welander, A.; Wesley, J.

    2008-10-16

    The poloidal field (PF) coil system on ITER, which provides both feedforward and feedback control of plasma position, shape, and current, is a critical element for achieving mission performance. Analysis of PF capabilities has focused on the 15 MA Q = 10 scenario with a 300-500 s flattop burn phase. The operating space available for the 15 MA ELMy H-mode plasma discharges in ITER and upgrades to the PF coils or associated systems to establish confidence that ITER mission objectives can be reached have been identified. Time dependent self-consistent free-boundary calculations were performed to examine the impact of plasma variability, discharge programming, and plasma disturbances. Based on these calculations a new reference scenario was developed based upon a large bore initial plasma, early divertor transition, low level heating in L-mode, and a late H-mode onset. Equilibrium analyses for this scenario indicate that the original PF coil limitations do not allow low li (<0.8) operation or lower flux states, and the flattop burn durations were predicted to be less than the desired 400 s. This finding motivates the expansion of the operating space, considering several upgrade options to the PF coils. Analysis was also carried out to examine the feedback current reserve required in the CS and PF coils during a series of disturbances and a feasibility assessment of the 17 MA scenario was undertaken. Results of the studies show that the new scenario and modified PF system will allow a wide range of 15 MA 300-500 s operation and more limited but finite 17 MA operation.

  2. Promoted-Combustion Chamber with Induction Heating Coil

    NASA Technical Reports Server (NTRS)

    Richardson, Erin; Hagood, Richard; Lowery, Freida; Herald, Stephen

    2006-01-01

    An improved promoted-combustion system has been developed for studying the effects of elevated temperatures on the flammability of metals in pure oxygen. In prior promoted-combustion chambers, initial temperatures of metal specimens in experiments have been limited to the temperatures of gas supplies, usually near room temperature. Although limited elevated temperature promoted-combustion chambers have been developed using water-cooled induction coils for preheating specimens, these designs have been limited to low-pressure operation due to the hollow induction coil. In contrast, the improved promoted-combustion chamber can sustain a pressure up to 10 kpsi (69 MPa) and, through utilization of a solid induction coil, is capable of preheating a metal specimen up to its melting point [potentially in excess of 2,000 F (approximately equal to 1,100 C)]. Hence, the improved promoted combustion chamber makes a greater range of physical conditions and material properties accessible for experimentation. The chamber consists of a vertical cylindrical housing with an inner diameter of 8 in. (20.32 cm) and an inner height of 20.4 in. (51.81 cm). A threaded, sealing cover at one end of the housing can be unscrewed to gain access for installing a specimen. Inlet and outlet ports for gases are provided. Six openings arranged in a helical pattern in the chamber wall contain sealed sapphire windows for viewing an experiment in progress. The base of the chamber contains pressure-sealed electrical connectors for supplying power to the induction coil. The connectors feature a unique design that prevents induction heating of the housing and the pressure sealing surfaces; this is important because if such spurious induction heating were allowed to occur, chamber pressure could be lost. The induction coil is 10 in. (25.4 cm) long and is fitted with a specimen holder at its upper end. At its lower end, the induction coil is mounted on a ceramic base, which affords thermal insulation to

  3. Pharmacological interference with protein-protein interactions mediated by coiled-coil motifs.

    PubMed

    Strauss, H M; Keller, S

    2008-01-01

    Coiled coils are bundles of intertwined alpha-helices that provide protein-protein interaction sites for the dynamic assembly and disassembly of protein complexes. The coiled-coil motif combines structural versatility and adaptability with mechanical strength and specificity. Multimeric proteins that rely on coiled-coil interactions are structurally and functionally very diverse, ranging from simple homodimeric transcription factors to elaborate heteromultimeric scaffolding clusters. Several coiled-coil-bearing proteins are of outstanding pharmacological importance, most notably SNARE proteins involved in vesicular trafficking of neurotransmitters and viral fusion proteins. Together with their crucial roles in many physiological and pathological processes, the structural simplicity and reversible nature of coiled-coil associations render them a promising target for pharmacological interference, as successfully exemplified by botulinum toxins and viral fusion inhibitors. The alpha-helical coiled coil is a ubiquitous protein domain that mediates highly specific homo- and heteromeric protein-protein interactions among a wide range of proteins. The coiled-coil motif was first proposed by Crick on the basis of X-ray diffraction data on alpha-keratin more than 50 years ago (Crick 1952, 1953) and nowadays belongs to the best-characterized protein interaction modules. By definition, a coiled coil is an oligomeric protein assembly consisting of several right-handed amphipathic alpha-helices that wind around each other into a superhelix (or a supercoil) in which the hydrophobic surfaces of the constituent helices are in continuous contact, forming a hydrophobic core. Both homomeric and heteromeric coiled coils with different stoichiometries are possible, and the helices can be aligned in either a parallel or an antiparallel topology (Harbury et al. 1993, 1994). Stoichiometry and topology are governed by the primary structure, that is, the sequence of the polypeptide chains

  4. Gamma ray spectrometer for ITER

    SciTech Connect

    Gin, D.; Chugunov, I.; Shevelev, A.; Khilkevitch, E.; Doinikov, D.; Naidenov, V.; Pasternak, A.; Polunovsky, I.; Kiptily, V.

    2014-08-21

    Gamma diagnostics is considered to be primary for the confined α-particles and runaway electrons measurements on ITER. The gamma spectrometer will be embedded into a neutron dump of the ITER Neutral Particle Analyzer diagnostic complex. It will supplement NPA measurements on the fuel isotope ratio and confined alphas/fast ions. In this paper an update on ITER gamma spectrometer developments is given. A new geometry of the system is described and detailed analysis of expected signals for the spectrometer is presented.

  5. 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

  6. Novel transcranial magnetic stimulation coil for mice

    NASA Astrophysics Data System (ADS)

    March, Stephen; Stark, Spencer; Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) shows potential for non-invasive treatment of various neurological disorders. Significant work has been performed on the design of coils used for TMS on human subjects but few reports have been made on the design of coils for use on the brains of animals such as mice. This work is needed as TMS studies utilizing mice can allow rapid preclinical development of TMS for human disorders but the coil designs developed for use on humans are inadequate for optimal stimulation of the much smaller mouse brain. A novel TMS coil has been developed with the goal of inducing strong and focused electric fields for the stimulation of small animals such as mice. Calculations of induced electric fields were performed utilizing an MRI derived inhomogeneous model of an adult male mouse. Mechanical and thermal analysis of this new TMS helmet-coil design have also been performed at anticipated TMS operating conditions to ensure mechanical stability of the new coil and establish expected linear attraction and rotational force values. Calculated temperature increases for typical stimulation periods indicate the helmet-coil system is capable of operating within established medical standards. A prototype of the coil has been fabricated and characterization results are presented.

  7. Magnetic Fields at the Center of Coils

    ERIC Educational Resources Information Center

    Binder, Philippe; Hui, Kaleonui; Goldman, Jesse

    2014-01-01

    In this note we synthesize and extend expressions for the magnetic field at the center of very short and very long current-carrying coils. Elementary physics textbooks present the following equation for the magnetic field inside a very long current-carrying coil (solenoid): B[subscript sol] = µ[subscript 0] (N/L) I, (1) where I is the current, N…

  8. Functional investigation of the plant-specific long coiled-coil proteins PAMP-INDUCED COILED-COIL (PICC) and PICC-LIKE (PICL) in Arabidopsis thaliana.

    PubMed

    Venkatakrishnan, Sowmya; Mackey, David; Meier, Iris

    2013-01-01

    We have identified and characterized two Arabidopsis long coiled-coil proteins PAMP-INDUCED COILED-COIL (PICC) and PICC-LIKE (PICL). PICC (147 kDa) and PICL (87 kDa) are paralogs that consist predominantly of a long coiled-coil domain (expanded in PICC), with a predicted transmembrane domain at the immediate C-terminus. Orthologs of PICC and PICL were found exclusively in vascular plants. PICC and PICL GFP fusion proteins are anchored to the cytoplasmic surface of the endoplasmic reticulum (ER) membrane by a C-terminal transmembrane domain and a short tail domain, via a tail-anchoring mechanism. T-DNA-insertion mutants of PICC and PICL as well as the double mutant show an increased sensitivity to the plant abiotic stress hormone abscisic acid (ABA) in a post-germination growth response. PICC, but not PICL gene expression is induced by the bacterial pathogen-associated molecular pattern (PAMP) flg22. T-DNA insertion alleles of PICC, but not PICL, show increased susceptibility to the non-virulent strain P. syringae pv. tomato DC3000 hrcC, but not to the virulent strain P. syringae pv. tomato DC3000. This suggests that PICC mutants are compromised in PAMP-triggered immunity (PTI). The data presented here provide first evidence for the involvement of a plant long coiled-coil protein in a plant defense response.

  9. Precise Fabrication of Electromagnetic-Levitation Coils

    NASA Technical Reports Server (NTRS)

    Ethridge, E.; Curreri, P.; Theiss, J.; Abbaschian, G.

    1985-01-01

    Winding copper tubing on jig ensures reproducible performance. Sequence of steps insures consistent fabrication of levitation-and-melting coils. New method enables technician to produce eight coils per day, 95 percent of them acceptable. Method employs precise step-by-step procedure on specially designed wrapping and winding jig.

  10. 49 CFR 236.730 - Coil, receiver.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Coil, receiver. 236.730 Section 236.730 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Coil, receiver. Concentric layers of insulated wire wound around the core of a receiver of an...

  11. 49 CFR 236.730 - Coil, receiver.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Coil, receiver. 236.730 Section 236.730 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Coil, receiver. Concentric layers of insulated wire wound around the core of a receiver of an...

  12. Undulator Long Coil Measurement System Tests

    SciTech Connect

    Wolf, Zachary; Levashov, Yurii; /SLAC

    2010-11-24

    The first and second field integrals in the LCLS undulators must be below a specified limit. To accurately measure the field integrals, a long coil system is used. This note describes a set of tests which were used to check the performance of the long coil system. A long coil system was constructed to measure the first and second field integrals of the LCLS undulators. The long coil measurements of the background fields were compared to field integrals obtained by sampling the background fields and numerically calculating the integrals. This test showed that the long coil has the sensitivity required to measure at the levels specified for the field integrals. Tests were also performed by making long coil measurements of short magnets of known strength placed at various positions The long coil measurements agreed with the known field integrals obtained by independent measurements and calculation. Our tests showed that the long coil measurements are a valid way to determine whether the LCLS undulator field integrals are below the specified limits.

  13. Helical axis stellarator with noninterlocking planar coils

    DOEpatents

    Reiman, A.; Boozer, A.H.

    1984-03-06

    The present invention generates stellarator fields having favorable properties (magnetic well and large rotational transform) by a simple coil system consisting only of unlinked planar non-circular coils. At large rotational transform toroidal effects on magnetic well and rotational transform are small and can be ignored. We do so herein, specializing in straight helical systems.

  14. Functional Investigation of the Plant-Specific Long Coiled-Coil Proteins PAMP-INDUCED COILED-COIL (PICC) and PICC-LIKE (PICL) in Arabidopsis thaliana

    PubMed Central

    Venkatakrishnan, Sowmya; Mackey, David; Meier, Iris

    2013-01-01

    We have identified and characterized two Arabidopsis long coiled-coil proteins PAMP-INDUCED COILED-COIL (PICC) and PICC-LIKE (PICL). PICC (147 kDa) and PICL (87 kDa) are paralogs that consist predominantly of a long coiled-coil domain (expanded in PICC), with a predicted transmembrane domain at the immediate C-terminus. Orthologs of PICC and PICL were found exclusively in vascular plants. PICC and PICL GFP fusion proteins are anchored to the cytoplasmic surface of the endoplasmic reticulum (ER) membrane by a C-terminal transmembrane domain and a short tail domain, via a tail-anchoring mechanism. T-DNA-insertion mutants of PICC and PICL as well as the double mutant show an increased sensitivity to the plant abiotic stress hormone abscisic acid (ABA) in a post-germination growth response. PICC, but not PICL gene expression is induced by the bacterial pathogen-associated molecular pattern (PAMP) flg22. T-DNA insertion alleles of PICC, but not PICL, show increased susceptibility to the non-virulent strain P. syringae pv. tomato DC3000 hrcC, but not to the virulent strain P. syringae pv. tomato DC3000. This suggests that PICC mutants are compromised in PAMP-triggered immunity (PTI). The data presented here provide first evidence for the involvement of a plant long coiled-coil protein in a plant defense response. PMID:23451199

  15. Functional investigation of the plant-specific long coiled-coil proteins PAMP-INDUCED COILED-COIL (PICC) and PICC-LIKE (PICL) in Arabidopsis thaliana.

    PubMed

    Venkatakrishnan, Sowmya; Mackey, David; Meier, Iris

    2013-01-01

    We have identified and characterized two Arabidopsis long coiled-coil proteins PAMP-INDUCED COILED-COIL (PICC) and PICC-LIKE (PICL). PICC (147 kDa) and PICL (87 kDa) are paralogs that consist predominantly of a long coiled-coil domain (expanded in PICC), with a predicted transmembrane domain at the immediate C-terminus. Orthologs of PICC and PICL were found exclusively in vascular plants. PICC and PICL GFP fusion proteins are anchored to the cytoplasmic surface of the endoplasmic reticulum (ER) membrane by a C-terminal transmembrane domain and a short tail domain, via a tail-anchoring mechanism. T-DNA-insertion mutants of PICC and PICL as well as the double mutant show an increased sensitivity to the plant abiotic stress hormone abscisic acid (ABA) in a post-germination growth response. PICC, but not PICL gene expression is induced by the bacterial pathogen-associated molecular pattern (PAMP) flg22. T-DNA insertion alleles of PICC, but not PICL, show increased susceptibility to the non-virulent strain P. syringae pv. tomato DC3000 hrcC, but not to the virulent strain P. syringae pv. tomato DC3000. This suggests that PICC mutants are compromised in PAMP-triggered immunity (PTI). The data presented here provide first evidence for the involvement of a plant long coiled-coil protein in a plant defense response. PMID:23451199

  16. Mechanical property tests on structural materials for ITER magnet system at low temperatures in China

    NASA Astrophysics Data System (ADS)

    Huang, Chuanjun; Huang, Rongjin; Li, Laifeng

    2014-01-01

    High field superconducting magnets need strong non-superconducting components for structural reinforcement. For instance, the ITER magnet system (MS) consists of cable-in-conduit conductor, coil case, magnet support, and insulating materials. Investigation of mechanical properties at magnet operation temperature with specimens machined at the final manufacturing stages of the conductor jacket materials, magnet support material, and insulating materials, even the component of the full-size conductor jacket is necessary to establish sound databases for the products. In China, almost all mechanical property tests of structural materials for the ITER MS, including conductor jacket materials of TF coils, PF coils, CCs, case material of CCs, conductor jacket materials of Main Busbars (MB) and Corrector Busbars (CB), material of magnet supports, and insulating materials of CCs have been carried out at the Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences (CAS). In this paper, the mechanical property test facilities are briefly demonstrated and the mechanical tests on the structural materials for the ITER MS, highlighting test rigs as well as test methods, are presented.

  17. Wireless adiabatic power transfer

    SciTech Connect

    Rangelov, A.A.; Suchowski, H.; Silberberg, Y.; Vitanov, N.V.

    2011-03-15

    Research Highlights: > Efficient and robust mid-range wireless energy transfer between two coils. > The adiabatic energy transfer is analogous to adiabatic passage in quantum optics. > Wireless energy transfer is insensitive to any resonant constraints. > Wireless energy transfer is insensitive to noise in the neighborhood of the coils. - Abstract: We propose a technique for efficient mid-range wireless power transfer between two coils, by adapting the process of adiabatic passage for a coherently driven two-state quantum system to the realm of wireless energy transfer. The proposed technique is shown to be robust to noise, resonant constraints, and other interferences that exist in the neighborhood of the coils.

  18. Optimization of data coils in a multiband wireless link for neuroprosthetic implantable devices.

    PubMed

    Uei-Ming Jow; Ghovanloo, M

    2010-10-01

    We have presented the design methodology along with detailed simulation and measurement results for optimizing a multiband transcutaneous wireless link for high-performance implantable neuroprosthetic devices. We have utilized three individual carrier signals and coil/antenna pairs for power transmission, forward data transmission from outside into the body, and back telemetry in the opposite direction. Power is transmitted at 13.56 MHz through a pair of printed spiral coils (PSCs) facing each other. Two different designs have been evaluated for forward data coils, both of which help to minimize power carrier interference in the received data carrier. One is a pair of perpendicular coils that are wound across the diameter of the power PSCs. The other design is a pair of planar figure-8 coils that are in the same plane as the power PSCs. We have compared the robustness of each design against horizontal misalignments and rotations in different directions. Simulation and measurements are also conducted on a miniature spiral antenna, designed to operate with impulse-radio ultra-wideband (IR-UWB) circuitry for back telemetry. PMID:21918679

  19. Rod-Coil Block Polyimide Copolymers

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Kinder, James D. (Inventor)

    2005-01-01

    This invention is a series of rod-coil block polyimide copolymers that are easy to fabricate into mechanically resilient films with acceptable ionic or protonic conductivity at a variety of temperatures. The copolymers consist of short-rigid polyimide rod segments alternating with polyether coil segments. The rods and coil segments can be linear, branched or mixtures of linear and branched segments. The highly incompatible rods and coil segments phase separate, providing nanoscale channels for ion conduction. The polyimide segments provide dimensional and mechanical stability and can be functionalized in a number of ways to provide specialized functions for a given application. These rod-coil black polyimide copolymers are particularly useful in the preparation of ion conductive membranes for use in the manufacture of fuel cells and lithium based polymer batteries.

  20. NMR local coil with adjustable spacing

    SciTech Connect

    Dembinski, G.T.

    1988-03-22

    A local coil assembly for use in NMR imaging is described which comprises: a base; a first local coil module mounted to the base and extending upward therefrom; sockets disposed in the base, each at a different distance from the first local coil module; a second local coil module having a connector therein which mates with each of the sockets to enable the second local coil module to be connected to the base at any one of the sockets; and a set of reactive components. The values of the respective reactive components are selected such that the second local oil module may be connected to any of the sockets without any substantial change in the resonant frequency of the assembly.

  1. Various factors affect coiled tubing limits

    SciTech Connect

    Yang, Y.S.

    1996-01-15

    Safety and reliability remain the primary concerns in coiled tubing operations. Factors affecting safety and reliability include corrosion, flexural bending, internal (or external) pressure and tension (or compression), and mechanical damage due to improper use. Such limits as coiled tubing fatigue, collapse, and buckling need to be understood to avoid disaster. With increased use of coiled tubing, operators will gain more experience. But at the same time, with further research and development of coiled tubing, the manufacturing quality will be improved and fatigue, collapse, and buckling models will become more mature, and eventually standard specifications will be available. This paper reviews the uses of coiled tubing and current research on mechanical behavior of said tubing. It also discusses several models used to help predict fatigue and failure levels.

  2. Channeled spectropolarimetry using iterative reconstruction

    NASA Astrophysics Data System (ADS)

    Lee, Dennis J.; LaCasse, Charles F.; Craven, Julia M.

    2016-05-01

    Channeled spectropolarimeters (CSP) measure the polarization state of light as a function of wavelength. Conventional Fourier reconstruction suffers from noise, assumes the channels are band-limited, and requires uniformly spaced samples. To address these problems, we propose an iterative reconstruction algorithm. We develop a mathematical model of CSP measurements and minimize a cost function based on this model. We simulate a measured spectrum using example Stokes parameters, from which we compare conventional Fourier reconstruction and iterative reconstruction. Importantly, our iterative approach can reconstruct signals that contain more bandwidth, an advancement over Fourier reconstruction. Our results also show that iterative reconstruction mitigates noise effects, processes non-uniformly spaced samples without interpolation, and more faithfully recovers the ground truth Stokes parameters. This work offers a significant improvement to Fourier reconstruction for channeled spectropolarimetry.

  3. Bi-2212/Ag tape conductor and coil development

    SciTech Connect

    Albert, G.W.; Leung, E.M.; Zhou, R.; Salazar, K.V.

    1996-12-31

    This paper presents recent progress by Los Alamos National Laboratory/Superconductivity Technology Center (LANL/STC) and Lockheed Martin Corporation/Advanced Development Operations (LMQADO) Energy and Power Systems group to jointly develop and test high temperature superconductor coils for practical applications such as motors, generators, magnetic bearings, superconducting magnetic energy storage (SMES), MAGLEV trains, or electrical inductors. Critical currents of 105 A/cm{sup 2} have been achieved in a Bi-2212/Ag tape conductor using a patented Ag addition process to improve core morphology and uniformity. Results of testing to measure key conductor parameters are presented along with design and analysis details of a general-purpose multi-layer HTS coil.

  4. A resonant biaxial Helmholtz coil employing a fractal capacitor bank

    NASA Astrophysics Data System (ADS)

    Martin, James E.

    2013-09-01

    The design and construction of a series resonant biaxial Helmholtz coil for the production of magnetic fields as large as 500 G in the range of 100-2500 Hz is described. Important aspects of ac coil design are discussed, including: minimizing power losses due to the expected Joule heating, self-induced eddy currents, and skin resistance; controlling the stray capacitance; maximizing field homogeneity; and keeping peak voltages at acceptable levels. The design and construction of a computer-controlled, optically isolated fractal capacitor bank is then treated, and various aspects of capacitor selection and characterization were discussed. The system performance is demonstrated, including stability and the possibility of field component dephasing with typical magnetic samples.

  5. A resonant biaxial Helmholtz coil employing a fractal capacitor bank.

    PubMed

    Martin, James E

    2013-09-01

    The design and construction of a series resonant biaxial Helmholtz coil for the production of magnetic fields as large as 500 G in the range of 100-2500 Hz is described. Important aspects of ac coil design are discussed, including: minimizing power losses due to the expected Joule heating, self-induced eddy currents, and skin resistance; controlling the stray capacitance; maximizing field homogeneity; and keeping peak voltages at acceptable levels. The design and construction of a computer-controlled, optically isolated fractal capacitor bank is then treated, and various aspects of capacitor selection and characterization were discussed. The system performance is demonstrated, including stability and the possibility of field component dephasing with typical magnetic samples. PMID:24089847

  6. CFD Analysis for Flow of Liquids in Coils

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Tarun Kanti; Das, Sudip Kumar

    2016-04-01

    The effects of liquid flow rate, coil diameter, pseudo plasticity of the liquids on the frictional pressure drop for the flow through helical coils have been reported through experimental investigation. Numerical modeling is carried using Fluent 6.3 software to find its applicability in the flow system. The Computational Fluid Dynamics (CFD) simulations are carried out using laminar non-Newtonian pseudo plastic power law model for laminar flow and k-ɛ model for turbulent flow for water. Water and dilute solution of Sodium Carboxy Methyl Cellulose (SCMC) as a non-Newtonian pseudo plastic fluid used for the study. Both hexahedral and tetrahedral grids are used for this simulation. The CFD results show the very good agreement with the experimental values. The comparison of the non-Newtonian liquid flow and water are also reported.

  7. 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.

  8. Design of the DEMO Fusion Reactor Following ITER

    PubMed Central

    Garabedian, Paul R.; McFadden, Geoffrey B.

    2009-01-01

    Runs of the NSTAB nonlinear stability code show there are many three-dimensional (3D) solutions of the advanced tokamak problem subject to axially symmetric boundary conditions. These numerical simulations based on mathematical equations in conservation form predict that the ITER international tokamak project will encounter persistent disruptions and edge localized mode (ELMS) crashes. Test particle runs of the TRAN transport code suggest that for quasineutrality to prevail in tokamaks a certain minimum level of 3D asymmetry of the magnetic spectrum is required which is comparable to that found in quasiaxially symmetric (QAS) stellarators. The computational theory suggests that a QAS stellarator with two field periods and proportions like those of ITER is a good candidate for a fusion reactor. For a demonstration reactor (DEMO) we seek an experiment that combines the best features of ITER, with a system of QAS coils providing external rotational transform, which is a measure of the poloidal field. We have discovered a configuration with unusually good quasisymmetry that is ideal for this task. PMID:27504224

  9. Performance improvement of a high-temperature superconducting coil by separating and grading the coil edge

    NASA Astrophysics Data System (ADS)

    Ishiguri, Shinichi; Funamoto, Taisuke

    2011-06-01

    In this paper, we establish a model to analyze the transport current performance of a high-temperature superconducting (HTS) coil, considering the dependencies of critical current and n-value of an HTS tape on magnetic field and magnetic field angles. This analysis shows that relatively large electric fields appear at the coil’s edges, preventing improvement in the transport current performance of the coil. To solve this problem, in this paper, we propose a graded coil in which several coil edges of different heights are separated and graded. Analysis of its performance shows that the coil’s critical current increases, thus confirming that there exists an optimum coil cross section at which the stored energy and central magnetic field improve 2.1 times and 45%, respectively, compared with a typical rectangular coil that employs the same total length of the HTS tape. It is recommended that these results of the coil should be applied to SMES.

  10. The ITER project construction status

    NASA Astrophysics Data System (ADS)

    Motojima, O.

    2015-10-01

    The pace of the ITER project in St Paul-lez-Durance, France is accelerating rapidly into its peak construction phase. With the completion of the B2 slab in August 2014, which will support about 400 000 metric tons of the tokamak complex structures and components, the construction is advancing on a daily basis. Magnet, vacuum vessel, cryostat, thermal shield, first wall and divertor structures are under construction or in prototype phase in the ITER member states of China, Europe, India, Japan, Korea, Russia, and the United States. Each of these member states has its own domestic agency (DA) to manage their procurements of components for ITER. Plant systems engineering is being transformed to fully integrate the tokamak and its auxiliary systems in preparation for the assembly and operations phase. CODAC, diagnostics, and the three main heating and current drive systems are also progressing, including the construction of the neutral beam test facility building in Padua, Italy. The conceptual design of the Chinese test blanket module system for ITER has been completed and those of the EU are well under way. Significant progress has been made addressing several outstanding physics issues including disruption load characterization, prediction, avoidance, and mitigation, first wall and divertor shaping, edge pedestal and SOL plasma stability, fuelling and plasma behaviour during confinement transients and W impurity transport. Further development of the ITER Research Plan has included a definition of the required plant configuration for 1st plasma and subsequent phases of ITER operation as well as the major plasma commissioning activities and the needs of the accompanying R&D program to ITER construction by the ITER parties.

  11. Skin and proximity effects in the conductors of split gradient coils for a hybrid Linac-MRI scanner.

    PubMed

    Tang, Fangfang; Lopez, Hector Sanchez; Freschi, Fabio; Smith, Elliot; Li, Yu; Fuentes, Miguel; Liu, Feng; Repetto, Maurizio; Crozier, Stuart

    2014-05-01

    In magnetic resonance imaging (MRI), rapidly changing gradient fields are applied to encode the magnetic resonance signal with spatial position; however eddy currents are induced in the surrounding conducting structures depending on the geometry of the conductor and the excitation waveform. These alternating fields change the spatial profile of the current density within the coil track with the applied frequencies of the input waveform and by their proximity to other conductors. In this paper, the impact of the conductor width and the excited frequency over the parameters that characterise the performance of split transverse and longitudinal gradient coils are studied. Thirty x-gradient coils were designed using a "free-surface" coil design method and the track width was varied from 1mm to 30mm with an increment value of 1mm; a frequency sweep analysis in the range of 100Hz to 10kHz was performed using the multi-layer integral method (MIM) and parameters such as power loss produced by the coil and generated in the cryostat, inductance, coil efficiency (field strength/operating current), magnetic field profile produced by the coil and the eddy currents were studied. An experimental validation of the theoretical model was performed on an example coil. Coils with filamentary conductor segments were also studied to compare the simulated parameters with those produced by coils with a finite track. There was found to be a significant difference between the parameters calculated using filamentary coils and those obtained when the coil is simulated using finite size tracks. A wider track width produces coil with superior efficiency and low resistance; however, due to the skin effect, the power loss increases faster in wider tracks than in those generated in coils with narrow tracks. It was demonstrated that rapidly changing current paths must be avoided in order to mitigate the power loss and the spatial asymmetry in the current density profile. The decision of using

  12. Skin and proximity effects in the conductors of split gradient coils for a hybrid Linac-MRI scanner

    NASA Astrophysics Data System (ADS)

    Tang, Fangfang; Lopez, Hector Sanchez; Freschi, Fabio; Smith, Elliot; Li, Yu; Fuentes, Miguel; Liu, Feng; Repetto, Maurizio; Crozier, Stuart

    2014-05-01

    In magnetic resonance imaging (MRI), rapidly changing gradient fields are applied to encode the magnetic resonance signal with spatial position; however eddy currents are induced in the surrounding conducting structures depending on the geometry of the conductor and the excitation waveform. These alternating fields change the spatial profile of the current density within the coil track with the applied frequencies of the input waveform and by their proximity to other conductors. In this paper, the impact of the conductor width and the excited frequency over the parameters that characterise the performance of split transverse and longitudinal gradient coils are studied. Thirty x-gradient coils were designed using a “free-surface” coil design method and the track width was varied from 1 mm to 30 mm with an increment value of 1 mm; a frequency sweep analysis in the range of 100 Hz to 10 kHz was performed using the multi-layer integral method (MIM) and parameters such as power loss produced by the coil and generated in the cryostat, inductance, coil efficiency (field strength/operating current), magnetic field profile produced by the coil and the eddy currents were studied. An experimental validation of the theoretical model was performed on an example coil. Coils with filamentary conductor segments were also studied to compare the simulated parameters with those produced by coils with a finite track. There was found to be a significant difference between the parameters calculated using filamentary coils and those obtained when the coil is simulated using finite size tracks. A wider track width produces coil with superior efficiency and low resistance; however, due to the skin effect, the power loss increases faster in wider tracks than in those generated in coils with narrow tracks. It was demonstrated that rapidly changing current paths must be avoided in order to mitigate the power loss and the spatial asymmetry in the current density profile. The decision of

  13. Using a modified 3D-printer for mapping the magnetic field of RF coils designed for fetal and neonatal imaging

    NASA Astrophysics Data System (ADS)

    Vavoulas, Alexander; Vaiopoulos, Nicholas; Hedström, Erik; Xanthis, Christos G.; Sandalidis, Harilaos G.; Aletras, Anthony H.

    2016-08-01

    An experimental setup for characterizing the magnetic field of MRI RF coils was proposed and tested. The setup consisted of a specially configured 3D-printer, a network analyzer and a mid-performance desktop PC. The setup was tested on a single loop RF coil, part of a phased array for fetal imaging. Then, the setup was used for determining the magnetic field characteristics of a high-pass birdcage coil used for neonatal MR imaging with a vertical static field. The scattering parameter S21, converted into power ratio, was used for mapping the B1 magnetic field. The experimental measurements from the loop coil were close to the theoretical results (R = 0.924). A high degree of homogeneity was measured for the neonatal birdcage RF coil. The development of MR RF coils is time consuming and resource intensive. The proposed experimental setup provides an alternative method for magnetic field characterization of RF coils used in MRI.

  14. Using a modified 3D-printer for mapping the magnetic field of RF coils designed for fetal and neonatal imaging.

    PubMed

    Vavoulas, Alexander; Vaiopoulos, Nicholas; Hedström, Erik; Xanthis, Christos G; Sandalidis, Harilaos G; Aletras, Anthony H

    2016-08-01

    An experimental setup for characterizing the magnetic field of MRI RF coils was proposed and tested. The setup consisted of a specially configured 3D-printer, a network analyzer and a mid-performance desktop PC. The setup was tested on a single loop RF coil, part of a phased array for fetal imaging. Then, the setup was used for determining the magnetic field characteristics of a high-pass birdcage coil used for neonatal MR imaging with a vertical static field. The scattering parameter S21, converted into power ratio, was used for mapping the B1 magnetic field. The experimental measurements from the loop coil were close to the theoretical results (R=0.924). A high degree of homogeneity was measured for the neonatal birdcage RF coil. The development of MR RF coils is time consuming and resource intensive. The proposed experimental setup provides an alternative method for magnetic field characterization of RF coils used in MRI. PMID:27310429

  15. Using a modified 3D-printer for mapping the magnetic field of RF coils designed for fetal and neonatal imaging.

    PubMed

    Vavoulas, Alexander; Vaiopoulos, Nicholas; Hedström, Erik; Xanthis, Christos G; Sandalidis, Harilaos G; Aletras, Anthony H

    2016-08-01

    An experimental setup for characterizing the magnetic field of MRI RF coils was proposed and tested. The setup consisted of a specially configured 3D-printer, a network analyzer and a mid-performance desktop PC. The setup was tested on a single loop RF coil, part of a phased array for fetal imaging. Then, the setup was used for determining the magnetic field characteristics of a high-pass birdcage coil used for neonatal MR imaging with a vertical static field. The scattering parameter S21, converted into power ratio, was used for mapping the B1 magnetic field. The experimental measurements from the loop coil were close to the theoretical results (R=0.924). A high degree of homogeneity was measured for the neonatal birdcage RF coil. The development of MR RF coils is time consuming and resource intensive. The proposed experimental setup provides an alternative method for magnetic field characterization of RF coils used in MRI.

  16. Decoupling of excitation and receive coils in pulsed magnetic resonance using sinusoidal magnetic field modulation

    NASA Astrophysics Data System (ADS)

    Tseytlin, Mark; Epel, Boris; Sundramoorthy, Subramanian; Tipikin, Dmitriy; Halpern, Howard J.

    2016-11-01

    In pulsed magnetic resonance, the excitation power is many orders of magnitude larger than that induced by the spin system in the receiving coil or resonator. The receiver must be protected during and immediately after the excitation pulse to allow for the energy stored in the resonator to dissipate to a safe level. The time during which the signal is not detected, the instrumental dead-time, can be shortened by using magnetically decoupled excitation and receive coils. Such coils are oriented, with respect to each other, in a way that minimizes the total magnetic flux produced by one coil in the other. We suggest that magnetically decoupled coils can be isolated to a larger degree by tuning them to separate frequencies. Spins are excited at one frequency, and the echo signal is detected at another. Sinusoidal magnetic field modulation that rapidly changes the Larmor frequency of the spins between the excitation and detection events is used to ensure the resonance conditions for both coils. In this study, the relaxation times of trityl-CD3 were measured in a field-modulated pulsed EPR experiment and compared to results obtained using a standard spin echo method. The excitation and receive coils were tuned to 245 and 256.7 MHz, respectively. Using an available rapid-scan, cross-loop EPR resonator, we demonstrated an isolation improvement of approximately 20-30 dB due to frequency decoupling. Theoretical analysis, numerical simulations, and proof-of-concept experiments demonstrated that substantial excitation-detection decoupling can be achieved. A pulsed L-band system, including a small volume bi-modal resonator equipped with modulation coils, was constructed to demonstrate fivefold dead-time reduction in comparison with the standard EPR experiment. This was achieved by detuning of the excitation and receive coils by 26 MHz and using sinusoidal modulation at 480 kHz.

  17. Simultaneous formation of right- and left-handed anti-parallel coiled-coil interfaces by a coil2 fragment of human lamin A.

    PubMed

    Kapinos, Larisa E; Burkhard, Peter; Herrmann, Harald; Aebi, Ueli; Strelkov, Sergei V

    2011-04-22

    The elementary building block of all intermediate filaments (IFs) is a dimer featuring a central α-helical rod domain flanked by the N- and C-terminal end domains. In nuclear IF proteins (lamins), the rod domain consists of two coiled-coil segments, coil1 and coil2, that are connected by a short non-helical linker. Coil1 and the C-terminal part of coil2 contain the two highly conserved IF consensus motifs involved in the longitudinal assembly of dimers. The previously solved crystal structure of a lamin A fragment (residues 305-387) corresponding to the second half of coil2 has yielded a parallel left-handed coiled coil. Here, we present the crystal structure and solution properties of another human lamin A fragment (residues 328-398), which is largely overlapping with fragment 305-387 but harbors a short segment of the tail domain. Unexpectedly, no parallel coiled coil forms within the crystal. Instead, the α-helices are arranged such that two anti-parallel coiled-coil interfaces are formed. The most significant interface has a right-handed geometry, which is accounted for by a characteristic 15-residue repeat pattern that overlays with the canonical heptad repeat pattern. The second interface is a left-handed anti-parallel coiled coil based on the predicted heptad repeat pattern. In solution, the fragment reveals only a weak dimerization propensity. We speculate that the C-terminus of coil2 might unzip, thereby allowing for a right-handed coiled-coil interface to form between two laterally aligned dimers. Such an interface might co-exist with a heterotetrameric left-handed coiled-coil assembly, which is expected to be responsible for the longitudinal A(CN) contact.

  18. Design of beta-domain swapping, alpha/beta-protein, environmentally sensitive coiled coil and peptide functionalized titania materials

    NASA Astrophysics Data System (ADS)

    Nagarkar, Radhika P.

    2009-12-01

    The objective of this dissertation is to apply rational peptide design to fabricate nanomaterials via self-assembly. This has been demonstrated in structurally diverse systems with an aim of deciphering the underlying principles governing how sequence affects the peptide's ability to adopt a specific secondary structure and ultimate material properties that are realized from the association of these secondary structural elements. Several amyloidogenic proteins have been shown to self-assemble into fibrils using a mechanism known as domain swapping. Here, discreet units of secondary structure are exchanged among discreet proteins during self-assembly to form extended networks with precise three dimensional organization. The possibility of using these mechanisms to design peptides capable of controlled assembly and fibril formation leading to materials with targeted properties is explored. By altering the placement of a beta-turn sequence that varies the size and location of the exchanged strand, twisting, non-twisting and laminated fibrillar nanostructures are obtained. Hydrogels prepared from these strand swapping beta-hairpins have varied rheological properties due to differences in their fibrillar nanostructures. In a second distinct design, alpha/beta-proteins are used to prepare environmentally sensitive hydrogels. Here, multiple distinct motifs for structural integrity and dynamic response within a single self-assembling peptide allow the amyloid-like fibrils formed to controllably alter their nano-topography in response to an external stimulus such as temperature. The development of these self-assembling alpha/beta-protein motifs also necessitated the design of pH sensitive antiparallel coiled coils. Exploring the basic principles responsible for pH dependent conformational changes in coiled coils can lead to new insights in the control of protein structure and function. Lastly, this dissertation discusses the interface between biomolecules and inorganic

  19. Visible and Infrared Optical Design for the ITER Upper Ports

    SciTech Connect

    Lasnier, C; Seppala, L; Morris, K; Groth, M; Fenstermacher, M; Allen, S; Synakowski, E; Ortiz, J

    2007-03-01

    This document contains the results of an optical design scoping study of visible-light and infrared optics for the ITER upper ports, performed by LLNL under contract for the US ITER Project Office. ITER is an international collaboration to build a large fusion energy tokamak with a goal of demonstrating net fusion power for pulses much longer than the energy confinement time. At the time of this report, six of the ITER upper ports are planned to each to contain a camera system for recording visible and infrared light, as well as other diagnostics. the performance specifications for the temporal and spatial resolution of this system are shown in the Section II, Functional Specifications. They acknowledge a debt to Y. Corre and co-authors of the CEA Cadarache report ''ITER wide-angle viewing and thermographic and visible system''. Several of the concepts used in this design are derived from that CEA report. The infrared spatial resolution for optics of this design is diffraction-limited by the size of the entrance aperture, at lower resolution than listed in the ITER diagnostic specifications. The size of the entrance aperture is a trade-off between spatial resolution, optics size in the port, and the location of relay optics. The signal-to-noise ratio allows operation at the specified time resolutions.

  20. Waste Tank cooling coil leakage calculations

    SciTech Connect

    Dworjanyn, L.O.

    1991-12-20

    A high activity Waste Tank cooling coil supply line cracked on September 12, 1991 at the H-Area East pump house, draining the cooling water to the ground. This raised the possibility of draining high-activity waste to the ground by siphon action through the submerged cycling coils since some of the cooling water supply lines are located up to 40 ft. below waste tank liquid level. The following documentation summarizes conclusions and provides details of flow calculation presented earlier during the incident investigation. No plausible reason for a simultaneous rupture of the supply line and the cooling coils inside the tank was identified. Both seismic stresses and water hammer produce relatively low stresses on the cooling coils. A hypothetical simultaneous rupture of the cooling coils inside the tank and the supply line below ground could result in 100 to 200 gpm waste discharge to the ground. Waste discharge from a possible cooling coil corrosion leak would be limited to 20 gal/12-hr shift under maximum possible siphon, based on operating procedures for cooling water makeup which call for coil isolation when a cooling water loss of 40 gal/shaft is identified. This level of discharge is within the existing envelope of accident consequences for Waste Tank Form SAR.

  1. Routine phasing of coiled-coil protein crystal structures with AMPLE

    PubMed Central

    Thomas, Jens M. H.; Keegan, Ronan M.; Bibby, Jaclyn; Winn, Martyn D.; Mayans, Olga; Rigden, Daniel J.

    2015-01-01

    Coiled-coil protein folds are among the most abundant in nature. These folds consist of long wound α-helices and are architecturally simple, but paradoxically their crystallographic structures are notoriously difficult to solve with molecular-replacement techniques. The program AMPLE can solve crystal structures by molecular replacement using ab initio search models in the absence of an existent homologous protein structure. AMPLE has been benchmarked on a large and diverse test set of coiled-coil crystal structures and has been found to solve 80% of all cases. Successes included structures with chain lengths of up to 253 residues and resolutions down to 2.9 Å, considerably extending the limits on size and resolution that are typically tractable by ab initio methodologies. The structures of two macromolecular complexes, one including DNA, were also successfully solved using their coiled-coil components. It is demonstrated that both the ab initio modelling and the use of ensemble search models contribute to the success of AMPLE by comparison with phasing attempts using single structures or ideal polyalanine helices. These successes suggest that molecular replacement with AMPLE should be the method of choice for the crystallo­graphic elucidation of a coiled-coil structure. Furthermore, AMPLE may be able to exploit the presence of a coiled coil in a complex to provide a convenient route for phasing. PMID:25866657

  2. Analysis of Coiled-Coil Interactions between Core Proteins of the Spindle Pole Body

    SciTech Connect

    Zizlsperger, N.; Malashkevich, V; Pillay, S; Keating, A

    2008-01-01

    The spindle pole body (SPB) is a multiprotein complex that organizes microtubules in yeast. Due to its large size and association with the nuclear membrane, little is known about its detailed structure. In particular, although many SPB components and some of the interactions between them have been identified, the molecular details of how most of these interactions occur are not known. The prevalence of predicted coiled-coil regions in SPB proteins suggests that some interactions may occur via coiled coils. Here this hypothesis is supported by biochemical characterization of isolated coiled-coil peptides derived from SPB proteins. Formation of four strongly self-associating coiled-coil complexes from Spc29, Spc42, and Spc72 was demonstrated by circular dichroism (CD) spectroscopy and a fluorescence resonance energy transfer (FRET) assay. Many weaker self- and heteroassociations were also detected by CD, FRET, and/or cross-linking. The thermal stabilities of nine candidate homooligomers were assessed; six unfolded cooperatively with melting temperatures ranging from <11 to >50 C. Solution studies established that coiled-coil peptides derived from Spc42 and Spc72 form parallel dimers, and this was confirmed for Spc42 by a high-resolution crystal structure. These data contribute to a growing body of knowledge that will ultimately provide a detailed model of the SPB structure.

  3. Crystal structure of a coiled-coil domain from human ROCK I.

    PubMed

    Tu, Daqi; Li, Yiqun; Song, Hyun Kyu; Toms, Angela V; Gould, Christopher J; Ficarro, Scott B; Marto, Jarrod A; Goode, Bruce L; Eck, Michael J

    2011-03-21

    The small GTPase Rho and one of its targets, Rho-associated kinase (ROCK), participate in a variety of actin-based cellular processes including smooth muscle contraction, cell migration, and stress fiber formation. The ROCK protein consists of an N-terminal kinase domain, a central coiled-coil domain containing a Rho binding site, and a C-terminal pleckstrin homology domain. Here we present the crystal structure of a large section of the central coiled-coil domain of human ROCK I (amino acids 535-700). The structure forms a parallel α-helical coiled-coil dimer that is structurally similar to tropomyosin, an actin filament binding protein. There is an unusual discontinuity in the coiled-coil; three charged residues (E613, R617 and D620) are positioned at what is normally the hydrophobic core of coiled-coil packing. We speculate that this conserved irregularity could function as a hinge that allows ROCK to adopt its autoinhibited conformation.

  4. Crystal Structure of the Central Coiled-Coil Domain from Human Liprin-[beta]2

    SciTech Connect

    Stafford, Ryan L.; Tang, Ming-Yun; Sawaya, Michael R.; Phillips, Martin L.; Bowie, James U.

    2012-02-07

    Liprins are a conserved family of scaffolding proteins important for the proper regulation and development of neuronal synapses. Humans have four liprin-{alpha}s and two liprin-{beta}s which all contain long coiled-coil domains followed by three tandem SAM domains. Complex interactions between the coiled-coil and SAM domains are thought to create liprin scaffolds, but the structural and biochemical properties of these domains remain largely uncharacterized. In this study we find that the human liprin-{beta}2 coiled-coil forms an extended dimer. Several protease-resistant subdomains within the liprin-{beta}1 and liprin-{beta}2 coiled-coils were also identified. A 2.0 {angstrom} crystal structure of the central, protease-resistant core of the liprin-{beta}2 coiled-coil reveals a parallel helix orientation. These studies represent an initial step toward determining the overall architecture of liprin scaffolds and understanding the molecular basis for their synaptic functions.

  5. Crystal structure of the central coiled-coil domain from human liprin-β2.

    PubMed

    Stafford, Ryan L; Tang, Ming-Yun; Sawaya, Michael R; Phillips, Martin L; Bowie, James U

    2011-05-10

    Liprins are a conserved family of scaffolding proteins important for the proper regulation and development of neuronal synapses. Humans have four liprin-αs and two liprin-βs which all contain long coiled-coil domains followed by three tandem SAM domains. Complex interactions between the coiled-coil and SAM domains are thought to create liprin scaffolds, but the structural and biochemical properties of these domains remain largely uncharacterized. In this study we find that the human liprin-β2 coiled-coil forms an extended dimer. Several protease-resistant subdomains within the liprin-β1 and liprin-β2 coiled-coils were also identified. A 2.0 Å crystal structure of the central, protease-resistant core of the liprin-β2 coiled-coil reveals a parallel helix orientation. These studies represent an initial step toward determining the overall architecture of liprin scaffolds and understanding the molecular basis for their synaptic functions.

  6. Cloning, overexpression, purification and crystallization of the CRN12 coiled-coil domain from Leishmania donovani

    PubMed Central

    Srivastava, Vijay Kumar; Rana, Ajay Kumar; Sahasrabuddhe, Amogh A.; Gupta, C. M; Pratap, J. V.

    2013-01-01

    Leishmania donovani coronin CRN12 is an actin-binding protein which consists of two domains: an N-terminal WD repeat domain and a C-terminal coiled-coil domain. The coiled-coil domain is 53 residues in length. Helix–helix interactions in general and coiled coils in particular are ubiquitous in the structure of proteins and play a significant role in the association among proteins, including supramolecular assemblies and transmembrane receptors that mediate cellular signalling, transport and actin dynamics. The L. donovani coronin CRN12 coiled-coil domain (5.8 kDa) was cloned, overexpressed, purified to homogeneity and the N-terminal 6×His tag was successfully removed by thrombin cleavage. Crystals of recombinant L. donovani coronin CRN12 coiled-coil domain were grown by vapour diffusion using a hanging-drop setup. Diffraction-quality crystals were obtained and data extending to 2.46 Å resolution were collected at 100 K on BM14, ESRF, Grenoble, France. The crystal belonged to the monoclinic space group C2, with unit-cell parameters a = 118.0, b = 50.6, c = 46.0 Å, β = 111.0°. Matthews coefficient (V M) calculations suggested the presence of 4–6 molecules in the asymmetric unit, corresponding to a solvent content of ∼33–55%, and are consistent with self-rotation function calculations. PMID:23695571

  7. Cloning, overexpression, purification and crystallization of the CRN12 coiled-coil domain from Leishmania donovani.

    PubMed

    Srivastava, Vijay Kumar; Rana, Ajay Kumar; Sahasrabuddhe, Amogh A; Gupta, C M; Pratap, J V

    2013-05-01

    Leishmania donovani coronin CRN12 is an actin-binding protein which consists of two domains: an N-terminal WD repeat domain and a C-terminal coiled-coil domain. The coiled-coil domain is 53 residues in length. Helix-helix interactions in general and coiled coils in particular are ubiquitous in the structure of proteins and play a significant role in the association among proteins, including supramolecular assemblies and transmembrane receptors that mediate cellular signalling, transport and actin dynamics. The L. donovani coronin CRN12 coiled-coil domain (5.8 kDa) was cloned, overexpressed, purified to homogeneity and the N-terminal 6×His tag was successfully removed by thrombin cleavage. Crystals of recombinant L. donovani coronin CRN12 coiled-coil domain were grown by vapour diffusion using a hanging-drop setup. Diffraction-quality crystals were obtained and data extending to 2.46 Å resolution were collected at 100 K on BM14, ESRF, Grenoble, France. The crystal belonged to the monoclinic space group C2, with unit-cell parameters a = 118.0, b = 50.6, c = 46.0 Å, β = 111.0°. Matthews coefficient (VM) calculations suggested the presence of 4-6 molecules in the asymmetric unit, corresponding to a solvent content of ∼33-55%, and are consistent with self-rotation function calculations. PMID:23695571

  8. COMMON COIL MAGNET PROGRAM AT BNL.

    SciTech Connect

    GUPTA, R.; ANERELLA, M.; COZZOLINO, J.; ESCALLIER, J.; GANETIS, G.; GHOSH, A.; HARRISON, M.; MORGAN, G.; MURATORE, J.; PARKER, B.; SAMPSON, W.; WANDERER, P.

    2000-09-17

    The goal of the common coil magnet R&D program at Brookhaven National Laboratory (BNL) is to develop a 12.5 T, 40 mm aperture dipole magnet using ''React and Wind Technology'' with High Temperature Superconductors (HTS) playing a major role. Due to its ''conductor friendly'' nature, the common coil design is attractive for building high field 2-in-1 dipoles with brittle materials such as HTS and Nb{sub 3}Sn. At the current rate of development, it is expected that a sufficient amount of HTS with the required performance would be available in a few years for building a short magnet. In the interim, the first generation dipoles will be built with Nb{sub 3}Sn superconductor. They will use a ''React and Wind'' technology similar to that used in HTS and will produce a 12.5 T central field in a 40 mm aperture. The Nb{sub 3}Sn coils and support structure of this magnet will become a part of the next generation hybrid magnet with inner coils made of HTS. To develop various aspects of the technology in a scientific and experimental manner, a 10-turn coil program has been started in parallel. The program allows a number of concepts to be evaluated with a rapid throughput in a cost-effective way. Three 10-turn Nb{sub 3}Sn coils have been built and one HTS coil is under construction. The initial test results of this ''React & Wind'' 10-turn coil program are presented. It is also shown that a common coil magnet design can produce a field quality that is as good as a conventional cosine theta design.

  9. ITER Construction--Plant System Integration

    SciTech Connect

    Tada, E.; Matsuda, S.

    2009-02-19

    This brief paper introduces how the ITER will be built in the international collaboration. The ITER Organization plays a central role in constructing ITER and leading it into operation. Since most of the ITER components are to be provided in-kind from the member countries, integral project management should be scoped in advance of real work. Those include design, procurement, system assembly, testing, licensing and commissioning of ITER.

  10. ITER project and fusion technology

    NASA Astrophysics Data System (ADS)

    Takatsu, H.

    2011-09-01

    In the sessions of ITR, FTP and SEE of the 23rd IAEA Fusion Energy Conference, 159 papers were presented in total, highlighted by the remarkable progress of the ITER project: ITER baseline has been established and procurement activities have been started as planned with a target of realizing the first plasma in 2019; ITER physics basis is sound and operation scenarios and operational issues have been extensively studied in close collaboration with the worldwide physics community; the test blanket module programme has been incorporated into the ITER programme and extensive R&D works are ongoing in the member countries with a view to delivering their own modules in a timely manner according to the ITER master schedule. Good progress was also reported in the areas of a variety of complementary activities to DEMO, including Broader Approach activities and long-term technology. This paper summarizes the highlights of the papers presented in the ITR, FTP and SEE sessions with a minimum set of background information.

  11. COIL emission of a modified negative branch confocal unstable resonator.

    PubMed

    Pargmann, Carsten; Hall, Thomas; Duschek, Frank; Grünewald, Karin Maria; Handke, Jürgen

    2007-11-01

    A modified negative branch confocal unstable resonator (MNBUR) was coupled to the chemical oxygen-iodine laser (COIL) device of the German Aerospace Center. It consists of two spherical mirrors and a rectangular scraper for power extraction. Experimentally measured distributions of the near- and far-field intensities and the near-field phase were found in close agreement to numerical calculations. The extracted power came up to approximately 90% of the power as expected for a stable resonator coupled to the same volume of the active medium. The output power revealed a considerable insensitivity towards tilts of the resonator mirrors and the ideal arrangement of the scraper was found to be straightforward by monitoring the near-field distributions of intensity and phase. The beam quality achieved with the MNBUR of an extremely low magnification of only 1.04 was rather poor but nevertheless in accordance with theory. The demonstrated consistency between theory and experiment makes the MNBUR an attractive candidate for lasers that allow for higher magnification. In particular, it promises high brilliance in application to 100 kW class COIL devices, superior to the conventional negative branch confocal unstable resonator. PMID:17973020

  12. Radiation analysis of the ITER pellet injection system

    SciTech Connect

    Gouge, M.J. ); Gomes, I.C.; Gomes, L.T.; Stevens, P.N, )

    1991-03-01

    The results of neutronics calculations for the pellet injection system of the International Thermonuclear Experimental Reactor (ITER) are described. Hands-on maintenance of components in the pellet injection room results in a considerable simplification of maintenance support equipment and in greater system availability. The basic configuration of the pellet injection system includes small-diameter guide tubes with which the pellet may have several small-angle collisions before reaching the plasma. The pellet injector port through which the guide tubes pass will be shared with ITER plasma diagnostics, so the calculation takes into account penetrations to accommodate numerous channels for a neutron spectrometer and neutron and gamma-ray cameras. The conservative assumption of steady-state operation of ITER for 1000 days was taken as the baseline for calculating the activation of components in the pellet injection room. The plasma configuration is based on the current ITER guidelines, the first wall configuration is based on the most recently updated configuration, and the blanket configuration is based on the US proposal for the blanket. The plasma, coils, and blanket regions were analyzed with the Monte Carlo code MCNP. The transport of neutrons through the penetrations was also performed with MCNP. The pellet injection room was modeled with the two-dimensional discrete ordinates code DORT, which was also used for the transport of neutrons during operation and of gamma rays caused by activation. The activation calculations were carried out with the REBATE code. Results from this study indicate that restricted personnel access to the pellet injection room is possible, so limited hands-on maintenance can be performed on the majority of the components in the room.

  13. Two-phase flow in helical and spiral coils

    NASA Technical Reports Server (NTRS)

    Keshock, Edward G.; Bush, Mia L.; Omrani, Adel; Yan, An

    1995-01-01

    Coiled tube heat exchangers involving two-phase flows are used in a variety of application areas, extending from the aerospace industry to petrochemical, refrigeration land power generation industries. The optimal design in each situation requires a fundamental understanding of the heat, mass and momentum transfer characteristic of the flowing two-phase mixture. However, two-phase flows in lengths of horizontal or vertical straight channels with heat transfer are often quite difficult in themselves to understand sufficiently well to permit accurate system designs. The present study has the following general objectives: (1) Observe two-phase flow patterns of air-water and R-113 working fluids over a range of flow conditions, for helical and spiral coil geometries, of circular and rectangular cross-section; (2) Compare observed flow patterns with predictions of existing flow maps; (3) Study criteria for flow regime transitions for possible modifications of existing flow pattern maps; and (4) Measure associated pressure drops across the coiled test sections over the rage of flow conditions specified.

  14. Coiled Fiber Pulsed Laser Simulator

    2009-01-29

    This suite of codes simulates the transient output pulse from an optically-pumped coiled fiber amplifier. The input pulse is assumed to have a Gaussian time dependence and a spatial dependence that may be Gaussian or an eigenmode of the straight of bent fiber computed using bend10 or bend20. Only one field component is used (semivectorial approximation). The fully-spatially-dependent fiber gain profile is specified is subroutines "inversion" and "interp_inversion" and is presently read from a datamore » file, although other means of specifying fiber gain could be reallized through modification of these subroutines. The input pulse is propagated through the fiber, including the following physical effects: spatial and temporal gain saturation, self-focusing, bend losses, and confinement from a user-defined fiber index profile. The user can follow the propagation progress with 3D graphics that show an intensity profile via user-modifiable cutting planes through the time space axes. A restart capability is also included. Approximate solutions in the frequency domain may be obtained much faster using the auxilliary codes bendbpm10 (full vector), bendbpm20 (semivectoral), and bendbpm21 (semivectoral with gain sheet spproximation for gain and self-focusing). These codes all include bend loss and spatial (but not temporal) gain saturation.« less

  15. Helical coil thermal hydraulic model

    NASA Astrophysics Data System (ADS)

    Caramello, M.; Bertani, C.; De Salve, M.; Panella, B.

    2014-11-01

    A model has been developed in Matlab environment for the thermal hydraulic analysis of helical coil and shell steam generators. The model considers the internal flow inside one helix and its associated control volume of water on the external side, both characterized by their inlet thermodynamic conditions and the characteristic geometry data. The model evaluates the behaviour of the thermal-hydraulic parameters of the two fluids, such as temperature, pressure, heat transfer coefficients, flow quality, void fraction and heat flux. The evaluation of the heat transfer coefficients as well as the pressure drops has been performed by means of the most validated literature correlations. The model has been applied to one of the steam generators of the IRIS modular reactor and a comparison has been performed with the RELAP5/Mod.3.3 code applied to an inclined straight pipe that has the same length and the same elevation change between inlet and outlet of the real helix. The predictions of the developed model and RELAP5/Mod.3.3 code are in fairly good agreement before the dryout region, while the dryout front inside the helical pipes is predicted at a lower distance from inlet by the model.

  16. X-ray scattering indicates that the leucine zipper is a coiled coil.

    PubMed Central

    Rasmussen, R; Benvegnu, D; O'Shea, E K; Kim, P S; Alber, T

    1991-01-01

    Dimerization of the bZIP class of eukaryotic transcriptional control proteins requires a sequence motif called the leucine zipper. We have grown two distinct crystal forms of a 33-amino acid peptide corresponding to the leucine zipper of the yeast transcriptional activator GCN4. This peptide is known to form a dimer of parallel helices in solution. X-ray scattering from both crystal forms shows reflections that are diagnostic of coiled coils. The most notable reflections occur at approximately 5.2 A resolution and correspond to the pitch of helices in coiled coils. There is no diffraction maximum near 5.4 A, the characteristic pitch of straight helices. Our results provide direct evidence that the leucine zipper of GCN4 is a coiled coil. Images PMID:1988953

  17. Krylov subspace iterations for the calculation of K-Eigenvalues with sn transport codes

    SciTech Connect

    Warsa, J. S.; Wareing, T. A.; Morel, J. E.; McGhee, J. M.; Lehoucq, R. B.

    2002-01-01

    We apply the Implicitly Restarted Arnoldi Method (IRAM), a Krylov subspace iterative method, to the calculation of k-eigenvalues for criticality problems. We show that the method can be implemented with only modest changes to existing power iteration schemes in an SN transport code. Numerical results on three dimensional unstructured tetrahedral meshes are shown. Although we only compare the IRAM to unaccelerated power iteration, the results indicate that the IRAM is a potentially efficient and powerful technique, especially for problems with dominance ratios approaching unity. Key Words: criticality eigenvalues, Implicitly Restarted Arnoldi Method (IRAM), deterministic transport methods

  18. Construction Safety Forecast for ITER

    SciTech Connect

    cadwallader, lee charles

    2006-11-01

    The International Thermonuclear Experimental Reactor (ITER) project is poised to begin its construction activity. This paper gives an estimate of construction safety as if the experiment was being built in the United States. This estimate of construction injuries and potential fatalities serves as a useful forecast of what can be expected for construction of such a major facility in any country. These data should be considered by the ITER International Team as it plans for safety during the construction phase. Based on average U.S. construction rates, ITER may expect a lost workday case rate of < 4.0 and a fatality count of 0.5 to 0.9 persons per year.

  19. Screen-printed flexible MRI receive coils

    NASA Astrophysics Data System (ADS)

    Corea, Joseph R.; Flynn, Anita M.; Lechêne, Balthazar; Scott, Greig; Reed, Galen D.; Shin, Peter J.; Lustig, Michael; Arias, Ana C.

    2016-03-01

    Magnetic resonance imaging is an inherently signal-to-noise-starved technique that limits the spatial resolution, diagnostic image quality and results in typically long acquisition times that are prone to motion artefacts. This limitation is exacerbated when receive coils have poor fit due to lack of flexibility or need for padding for patient comfort. Here, we report a new approach that uses printing for fabricating receive coils. Our approach enables highly flexible, extremely lightweight conforming devices. We show that these devices exhibit similar to higher signal-to-noise ratio than conventional ones, in clinical scenarios when coils could be displaced more than 18 mm away from the body. In addition, we provide detailed material properties and components performance analysis. Prototype arrays are incorporated within infant blankets for in vivo studies. This work presents the first fully functional, printed coils for 1.5- and 3-T clinical scanners.

  20. Screen-printed flexible MRI receive coils.

    PubMed

    Corea, Joseph R; Flynn, Anita M; Lechêne, Balthazar; Scott, Greig; Reed, Galen D; Shin, Peter J; Lustig, Michael; Arias, Ana C

    2016-01-01

    Magnetic resonance imaging is an inherently signal-to-noise-starved technique that limits the spatial resolution, diagnostic image quality and results in typically long acquisition times that are prone to motion artefacts. This limitation is exacerbated when receive coils have poor fit due to lack of flexibility or need for padding for patient comfort. Here, we report a new approach that uses printing for fabricating receive coils. Our approach enables highly flexible, extremely lightweight conforming devices. We show that these devices exhibit similar to higher signal-to-noise ratio than conventional ones, in clinical scenarios when coils could be displaced more than 18 mm away from the body. In addition, we provide detailed material properties and components performance analysis. Prototype arrays are incorporated within infant blankets for in vivo studies. This work presents the first fully functional, printed coils for 1.5- and 3-T clinical scanners. PMID:26961073

  1. Cooling arrangement for a superconducting coil

    DOEpatents

    Herd, K.G.; Laskaris, E.T.

    1998-06-30

    A superconducting device is disclosed, such as a superconducting rotor for a generator or motor. A vacuum enclosure has an interior wall surrounding a cavity containing a vacuum. A superconductive coil is placed in the cavity. A generally-annularly-arranged, thermally-conductive sheet has an inward-facing surface contacting generally the entire outward-facing surface of the superconductive coil. A generally-annularly-arranged coolant tube contains a cryogenic fluid and contacts a generally-circumferential portion of the outward-facing surface of the sheet. A generally-annularly-arranged, thermally-insulative coil overwrap generally circumferentially surrounds the sheet. The coolant tube and the inward-facing surface of the coil overwrap together contact generally the entire outward-facing surface of the sheet. 3 figs.

  2. The Magnetic Field of Helmholtz Coils

    ERIC Educational Resources Information Center

    Berridge, H. J. J.

    1975-01-01

    Describes the magnetic field of Helmholtz coils qualitatively and then provides the basis for a quantitative expression. Since the mathematical calculations are very involved, a computer program for solving the mathematical expression is presented and explained. (GS)

  3. Cooling arrangement for a superconducting coil

    DOEpatents

    Herd, Kenneth Gordon; Laskaris, Evangelos Trifon

    1998-06-30

    A superconducting device, such as a superconducting rotor for a generator or motor. A vacuum enclosure has an interior wall surrounding a cavity containing a vacuum. A superconductive coil is placed in the cavity. A generally-annularly-arranged, thermally-conductive sheet has an inward-facing surface contacting generally the entire outward-facing surface of the superconductive coil. A generally-annularly-arranged coolant tube contains a cryogenic fluid and contacts a generally-circumferential portion of the outward-facing surface of the sheet. A generally-annularly-arranged, thermally-insulative coil overwrap generally circumferentially surrounds the sheet. The coolant tube and the inward-facing surface of the coil overwrap together contact generally the entire outward-facing surface of the sheet.

  4. Modular design of receiver coil arrays.

    PubMed

    De Zanche, Nicola; Massner, Jurek A; Leussler, Christoph; Pruessmann, Klaas P

    2008-07-01

    We describe a modular and hence flexible system for connecting MR surface coils to create a receiver array. Up to 16 individual coils of different size and shape depending on the application are plugged into a connector box that houses the control electronics. Preamplification, matching and detuning circuitry are housed on a circuit board directly attached to each coil loop. Electrical adjustments for tuning or decoupling for each coil configuration are not needed thanks to effective preamplifier decoupling provided through a Pi matching network. Radio-frequency safety and electrically stable cabling are ensured by multiple radio-frequency traps. Array modules for 1.5 and 3 T have been simulated, constructed, tested, and used for imaging experiments.

  5. Electrical wire insulation and electromagnetic coil

    DOEpatents

    Bich, George J.; Gupta, Tapan K.

    1984-01-01

    An electromagnetic coil for high temperature and high radiation application in which glass is used to insulate the electrical wire. A process for applying the insulation to the wire is disclosed which results in improved insulation properties.

  6. Coiling Temperature Control in Hot Strip Mill

    NASA Astrophysics Data System (ADS)

    Imanari, Hiroyuki; Fujiyama, Hiroaki

    Coiling temperature is one of the most significant factors in products of hot strip mill to determine material properties such as strength, toughness of steel, so it is very important to achieve accurate coiling temperature control (CTC). Usually there are a few pyrometers on the run out table in hot strip mill, therefore temperature model and its adapting system have large influences on the accuracy of CTC. Also unscheduled change of rolling speed has a bad effect to keep coiling temperature as its target. Newly developed CTC system is able to get very accurate coiling temperature against uncertain factors and disturbances by adopting easily identified temperature model, learning method and dynamic set up function. The features of the CTC system are discussed with actual data, and the effectiveness of the system is shown by actual control results.

  7. Functional Analysis of the Bacteriophage T4 Rad50 Homolog (gp46) Coiled-coil Domain.

    PubMed

    Barfoot, Tasida; Herdendorf, Timothy J; Behning, Bryanna R; Stohr, Bradley A; Gao, Yang; Kreuzer, Kenneth N; Nelson, Scott W

    2015-09-25

    Rad50 and Mre11 form a complex involved in the detection and processing of DNA double strand breaks. Rad50 contains an anti-parallel coiled-coil with two absolutely conserved cysteine residues at its apex. These cysteine residues serve as a dimerization domain and bind a Zn(2+) cation in a tetrathiolate coordination complex known as the zinc-hook. Mutation of the zinc-hook in bacteriophage T4 is lethal, indicating the ability to bind Zn(2+) is critical for the functioning of the MR complex. In vitro, we found that complex formation between Rad50 and a peptide corresponding to the C-terminal domain of Mre11 enhances the ATPase activity of Rad50, supporting the hypothesis that the coiled-coil is a major conduit for communication between Mre11 and Rad50. We constructed mutations to perturb this domain in the bacteriophage T4 Rad50 homolog. Deletion of the Rad50 coiled-coil and zinc-hook eliminates Mre11 binding and ATPase activation but does not affect its basal activity. Mutation of the zinc-hook or disruption of the coiled-coil does not affect Mre11 or DNA binding, but their activation of Rad50 ATPase activity is abolished. Although these mutants excise a single nucleotide at a normal rate, they lack processivity and have reduced repetitive exonuclease rates. Restricting the mobility of the coiled-coil eliminates ATPase activation and repetitive exonuclease activity, but the ability to support single nucleotide excision is retained. These results suggest that the coiled-coiled domain adopts at least two conformations throughout the ATPase/nuclease cycle, with one conformation supporting enhanced ATPase activity and processivity and the other supporting nucleotide excision.

  8. Coiled-coils as assembly-directing domains in self-assembling structures

    NASA Astrophysics Data System (ADS)

    Sahin, Erinc

    2008-10-01

    The bioconjugation of proteins and peptides with synthetic polymers is a promising method to tailor chemical, biological and physical properties of both the polymeric and protein-based components. Here, we describe macromolecular assemblies of polyethylene glycol-coiled-coil alternating block copolymers guided by associations of coiled-coils. High molecular weight, alternating block copolymers of PEG and coiled-coil peptides were formed via facile reactions between N-hydroxysuccinimide esters and amines, leading to amide bond formation under anhydrous conditions. Confirmation of multiblock formation was assessed via a combination of NMR spectroscopy, size-exclusion chromatography, and electrophoretic analysis. Formation of the alternating block copolymers of PEG with coiled-coil peptides through the f-position on the heptads did not impair the ability of the coiled-coils to form heterodimers, as assessed via circular dichroic spectroscopy. Interestingly, the conjugation triggered homooligomer formation in one of the peptides that is monomeric in the absence of PEG. The macromolecular assembly of the homooligomer was characterized via circular dichroism, analytical ultracentrifugation, and dynamic and static light scattering. The copolymer structures were formed under physiological conditions, and exhibited controlled sizes relevant in applications such as drug delivery and controlled release. Our efforts toward synthesis of coiled-coils via recombinant expression have also lead to the discovery of an evolutionary phenomenon. We observed a strong inverse correlation between the pH of an organism's habitat and its proteomic pI, that is the isoelectric point of bulk of its proteome. This observation may be useful in informed selection of host organisms for recombinant expression of proteins with extreme isoelectric points.

  9. Conical coils counter-current chromatography for preparative isolation and purification of tanshinones from Salvia miltiorrhiza Bunge.

    PubMed

    Liang, Junling; Meng, Jie; Guo, Mengzhe; Yang, Zhi; Wu, Shihua

    2013-05-01

    Modern counter-current chromatography (CCC) originated from the helical coil planet centrifuge. Recently, spiral coils were found to possess higher separation efficiency in both the retention of stationary phase and solutes resolution than other CCC coils like the helical and toroidal coils used on type-J CCC and cross-axis CCC. In this work, we built a novel conical coil CCC for the preparative isolation and purification of tanshinones from Salvia miltiorrhiza Bunge. The conical coils were wound on three identical upright tapered holders in head-to-tail and left-handed direction and connected in series. Compared with helical and spiral coil CCC, conical coil CCC not only placed CCC column in a two-dimensional centrifugal field, but also provided a potential centrifugal force gradient both in axial and radial directions. The extra centrifugal gradient made mobile phase move faster and enabled CCC much higher retention of stationary phase and better resolution. As a result, higher efficiency has been obtained with the solvent system of hexane-ethyl acetate-methanol-water (HEMWat) with the volume ratio of 5:5:7:3 by using conical coil CCC apparatus. Four tanshinones, including cryptotanshinone (1), tanshinone I (2), 1,2-dihydrotanshinquinone (3) and tanshinone IIA (4), were well resolved from 500mg to 1g crude samples with high purity. Furthermore, the conical coil CCC can make a much higher solid phase retention, which makes it to be a powerful separation tool with high throughput. This is the first report about conical coil CCC for separation of tanshinones and it may also be an important advancement for natural products isolation.

  10. Passive energy dump for superconducting coil protection

    DOEpatents

    Luton, J.N. Jr.

    1973-01-16

    The patent describes a passive resistance type energy dump for the protection of the coils of a superconducting magnet. Insertion heaters are immersed in a rigid container filled with a fusible alloy. The energy dump is connected across the coils of the superconducting magnet wherein individual heater elements are connected singly to the windings or otherwise according to the energy dumping requirements upon transition of the magnet to a normal state.

  11. Modular test facility for HTS insert coils

    SciTech Connect

    Lombardo, V; Bartalesi, A.; Barzi, E.; Lamm, M.; Turrioni, D.; Zlobin, A.V.; /Fermilab

    2009-10-01

    The final beam cooling stages of a Muon Collider may require DC solenoid magnets with magnetic fields in the range of 40-50 T. In this paper we will present a modular test facility developed for the purpose of investigating very high field levels with available 2G HTS superconducting materials. Performance of available conductors is presented, together with magnetic calculations and evaluation of Lorentz forces distribution on the HTS coils. Finally a test of a double pancake coil is presented.

  12. AC loss measurements in HTS coil assemblies with hybrid coil structures

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenan; Long, Nicholas J.; Staines, Mike; Badcock, Rodney A.; Bumby, Chris W.; Buckley, Robert G.; Amemiya, Naoyuki

    2016-09-01

    Both AC loss and wire cost in coil windings are critical factors for high temperature superconductor (HTS) AC machinery applications. We present AC loss measurement results in three HTS coil assemblies at 77 K and 65 K which have a hybrid coil structure comprising one central winding (CW) and two end windings (EWs) wound with ReBCO and BSCCO wires with different self-field I c values at 77 K. All AC loss results in the coil assemblies are hysteretic and the normalized AC losses in the coil assemblies at different temperatures can be scaled with the I c value of the coil assemblies. The normalised results show that AC loss in a coil assembly with BSCCO CW can be reduced by using EWs wound with high I c ReBCO wires, whilst further AC loss reduction can be achieved by replacing the BSCCO CW with ReBCO CW. The results imply that a flexible hybrid coil structure is possible which considers both AC loss and wire cost in coil assemblies.

  13. Insertion of a coiled-coil peptide from influenza virus hemagglutinin into membranes

    SciTech Connect

    Yu, Y.G.; Shin, Y.K.; King, D.S.

    1994-10-14

    The trimeric protein hemagglutinin (HA) of the influenza viral envelope is essential for cell entry. To investigate the interaction of HA with membranes, two 40-residue, cysteine-substituted peptides comprising the loop region and the first part of the coiled-coil stem were synthesized and modified with a nitroxide spin label. Electron paramagnetic resonance analysis revealed that the peptide inserts reversibly into phospholipid vesicles under endosomal pH conditions. This result suggests that some or all of the long coiled-coil trimer of HA may insert into membranes, which could bring the viral and cell membranes closer together and facilitate fusion. 16 refs., 5 figs.

  14. The real mission of ITER

    SciTech Connect

    Wurden, G A

    2009-01-01

    For future machines, the plasma stored energy is going up by factors of 20-40x, and plasma currents by 2-3x, while the surface to volume ratio is at the same time decreasing. Therefore the disruption forces, even for constant B, (which scale like IxB), and associated possible localized heating on machine components, are more severe. Notably, Tore Supra has demonstrated removal of more than 1 GJ of input energy, over nearly a 400 second period. However, the instantaneous stored energy in the Tore Supra system (which is most directly related to the potential for disruption damage) is quite small compared to other large tokamaks. The goal of ITER is routinely described as studying DT burning plasmas with a Q {approx} 10. In reality, ITER has a much more important first order mission. In fact, if it fails at this mission, the consequences are that ITER will never get to the eventual stated purpose of studying a burning plasma. The real mission of ITER is to study (and demonstrate successfully) plasma control with {approx}10-17 MA toroidal currents and {approx}100-400 MJ plasma stored energy levels in long-pulse scenarios. Before DT operation is ever given a go-ahead in ITER, the reality is that ITER must demonstrate routine and reliable control of high energy hydrogen (and deuterium) plasmas. The difficulty is that ITER must simultaneously deal with several technical problems: (1) heat removal at the plasma/wall interface, (2) protection of the wall components from off-normal events, and (3) generation of dust/redeposition of first wall materials. All previous tokamaks have encountered hundred's of major disruptions in the course of their operation. The consequences of a few MA of runaway electrons (at 20-50 MeV) being generated in ITER, and then being lost to the walls are simply catastrophic. They will not be deposited globally, but will drift out (up, down, whatever, depending on control system), and impact internal structures, unless 'ameliorated'. Basically, this

  15. Iterated binomial sums and their associated iterated integrals

    NASA Astrophysics Data System (ADS)

    Ablinger, J.; Blümlein, J.; Raab, C. G.; Schneider, C.

    2014-11-01

    We consider finite iterated generalized harmonic sums weighted by the binomial binom{2k}{k} in numerators and denominators. A large class of these functions emerges in the calculation of massive Feynman diagrams with local operator insertions starting at 3-loop order in the coupling constant and extends the classes of the nested harmonic, generalized harmonic, and cyclotomic sums. The binomially weighted sums are associated by the Mellin transform to iterated integrals over square-root valued alphabets. The values of the sums for N → ∞ and the iterated integrals at x = 1 lead to new constants, extending the set of special numbers given by the multiple zeta values, the cyclotomic zeta values and special constants which emerge in the limit N → ∞ of generalized harmonic sums. We develop algorithms to obtain the Mellin representations of these sums in a systematic way. They are of importance for the derivation of the asymptotic expansion of these sums and their analytic continuation to N in {C}. The associated convolution relations are derived for real parameters and can therefore be used in a wider context, as, e.g., for multi-scale processes. We also derive algorithms to transform iterated integrals over root-valued alphabets into binomial sums. Using generating functions we study a few aspects of infinite (inverse) binomial sums.

  16. DESIGN, FABRICATION, INSTALLATION, TESTING AND INITIAL RESULTS OF IN-VESSEL CONTROL COILS FOR DIII-D

    SciTech Connect

    ANDERSON,P.M; BAXI,C.B; KELLMAN,A.G; REIS,E.E

    2003-10-01

    OAK-B135 Since 1995, DIII-D has performed correction of magnetic field imperfections using a set of six external picture frame coils located on the vessel mid-plane. In 2000, these coils also demonstrated benefits when used for feedback of the resistive wall mode, an instability that limits the plasma performance at high beta. Modeling has shown that substantial performance improvements could be achieved by installing new coils inside the vessel and expanding the poloidal coverage above and below the mid-plane. Two prototype internal coils were installed in 2001 and were power tested successfully after several bakes to 350 C. A full set of twelve internal coils and related magnetic sensors are now operational in the DIII-D tokamak. The design requirements for the new coil system was to maximize the magnetic field at the plasma edge, operate with a frequency range of dc to 1000 Hz, and fit behind the existing graphite wall tiles. The coil design adopted and installed is a water-cooled hollow copper conductor insulated with polyamide and housed inside a stainless steel tube that forms a vacuum boundary. The coil is rigidly mounted to the inside of the vacuum vessel. The primary challenge in the design of these coils wa sin joining of both the copper conductor and the stainless tube without overheating the polyamide insulator. Elastic-plastic analysis was used to demonstrate acceptable thermal stresses during baking conditions. Analysis determined the optimum water cooling channel diameter. The coils were tested in high toroidal field to the limit of the power supply of 4.5 kA DC with inductance-limited current for frequencies between 300 Hz and 1000 Hz. Recent results are presented.

  17. Image reconstructions with the rotating RF coil

    NASA Astrophysics Data System (ADS)

    Trakic, A.; Wang, H.; Weber, E.; Li, B. K.; Poole, M.; Liu, F.; Crozier, S.

    2009-12-01

    Recent studies have shown that rotating a single RF transceive coil (RRFC) provides a uniform coverage of the object and brings a number of hardware advantages (i.e. requires only one RF channel, averts coil-coil coupling interactions and facilitates large-scale multi-nuclear imaging). Motion of the RF coil sensitivity profile however violates the standard Fourier Transform definition of a time-invariant signal, and the images reconstructed in this conventional manner can be degraded by ghosting artifacts. To overcome this problem, this paper presents Time Division Multiplexed — Sensitivity Encoding (TDM-SENSE), as a new image reconstruction scheme that exploits the rotation of the RF coil sensitivity profile to facilitate ghost-free image reconstructions and reductions in image acquisition time. A transceive RRFC system for head imaging at 2 Tesla was constructed and applied in a number of in vivo experiments. In this initial study, alias-free head images were obtained in half the usual scan time. It is hoped that new sequences and methods will be developed by taking advantage of coil motion.

  18. Modifying Wire Array Z-pinch Ablation Structure and Implosion Dynamics Using Coiled Arrays

    SciTech Connect

    Hall, Gareth N.; Bland, Simon N.; Lebedev, Sergey V.; Chittenden, Jeremy P.; Palmer, James B. A.; Suzuki-Vidal, Francisco A.; Swadling, George F.; Niasse, Nicolas; Knapp, P. F.; Blesener, I. C.; McBride, R. D.; Chalenski, D. A.; Bell, K. S.; Greenly, J. B.; Blanchard, T.; Wilhelm, H.; Hammer, D. A.; Kusse, B. R.; Bott, Simon C.

    2009-01-21

    Coiled arrays, a cylindrical array in which each wire is formed into a helix, suppress the modulation of ablation at the fundamental wavelength. Outside the vicinity of the wire cores, ablation flow from coiled arrays is modulated at the coil wavelength and has a 2-stream structure in the r,{theta} plane. Within the vicinity of the helical wires, ablation is concentrated at positions with the greatest azimuthal displacement and plasma is axially transported from these positions such that the streams become aligned with sections of the coil furthest from the array axis. The GORGON MHD code accurately reproduces this observed ablation structure, which can be understood in terms of JxB forces that result from the interaction of the global magnetic field with a helical current path as well as additional current paths suggested by the simulations. With this ability to control where ablation streamers occur, large wavelength coils were constructed such that the breaks that form in the wires had sufficient axial separation to prevent perturbations in the implosion sheath from merging. This produces a new mode of implosion in which the global instability can be controlled and perturbations correlated between all wires in an array. For large wavelength 8-wire coiled arrays, this produced a dramatic increase in x-ray power, equalling that of a 32-wire straight array. These experiments were carried out on the MAGPIE generator (1 MA, 240 ns) at Imperial College, and the COBRA generator (1 MA, 100 ns) at Cornell University.

  19. The Influence of Eddy Effect of Coils on Flow and Temperature Fields of Molten Droplet in Electromagnetic Levitation Device

    NASA Astrophysics Data System (ADS)

    Feng, Lin; Shi, Wan-Yuan

    2015-08-01

    In this work, the influence of eddy effect of coils on magnetic, flow, and temperature fields in an electromagnetically levitated molten droplet was investigated by a serial of axisymmetric numerical simulations. In an electromagnetic levitation device, both metal droplet and coils are conductive materials, therefore the distributions of current density in them should be non-uniform as a result of the eddy effect. However, in previous works, the eddy effect was considered alone in metal droplet but ignored in coils usually. As the distance of coils and metal droplet is several millimetres in general, the non-uniform distribution of current density in coils actually gives important influences on calculations of magnetic, flow, and temperature fields. Here, we consider the eddy effect both in metal droplet as well as that in coils simultaneously. Lifting force, absorbed power, fluid flow, and temperature field inside a 4-mm radius molten copper droplet as a typical example are then calculated and analyzed carefully under such condition. The results show that eddy effect leads to higher magnetic force, velocity, and temperature in both levitating and melting processes than those when the eddy effect is ignored. What is more, such influence increases as the distance of droplet and coils becomes closer, which corresponds to experimental measurement. Therefore, we suggest that eddy effect of coils should be considered in numerical simulation on this topic to obtain more reliable result.

  20. Graphene-coated coupling coil for AC resistance reduction

    DOEpatents

    Miller, John M

    2014-03-04

    At least one graphene layer is formed to laterally surround a tube so that the basal plane of each graphene layer is tangential to the local surface of the tube on which the graphene layer is formed. An electrically conductive path is provided around the tube for providing high conductivity electrical path provided by the basal plane of each graphene layer. The high conductivity path can be employed for high frequency applications such as coupling coils for wireless power transmission to overcome skin depth effects and proximity effects prevalent in high frequency alternating current paths.

  1. Radiation-hard electrical coil and method for its fabrication

    DOEpatents

    Grieggs, R.J.; Blake, R.D.; Gac, F.D.

    1982-06-29

    A radiation-hard insulated electrical coil and method for making the same are disclosed. In accordance with the method, a conductor, preferably copper, is wrapped with an aluminum strip and then tightly wound into a coil. The aluminum-wrapped coil is then annealed to relax the conductor in the coiled configuration. The annealed coil is then immersed in an alkaline solution to dissolve the aluminum strip, leaving the bare conductor in a coiled configuration with all of the windings closely packed yet uniformly spaced from one another. The coil is then insulated with a refractory insulating material. In the preferred embodiment, the coil is insulated by coating it with a vitreous enamel and subsequently potting the enamelled coil in a castable ceramic concrete. The resulting coil is substantially insensitive to radiation and may be operated continuously in high radiation environments for long periods of time.

  2. Research on JET in view of ITER

    NASA Astrophysics Data System (ADS)

    Pamela, Jerome; Ongena, Jef; Watkins, Michael

    2004-11-01

    Research on JET is focused on further development of the two ITER reference plasma scenarios. The ELMy H-Mode, has been extended to lower rho* at high and q_95=3, with simultaneously H_98=0.9, and f_GW=0.9 at I_p=3.5 MA. The dependence of confinement on beta and rho* has been found to be more favorable than given by the IPB98(y,2) scaling. Highlights in the development of Advanced Regimes with Internal Transport Barriers (ITB) and strong reversed shear (q_0=2-3, q_min=1.5-2.5) are : (i) operation at a core density close to the Greenwald limit and (ii) full current drive in 3T/1.8MA ITB plasmas extended to 20 seconds with a JET record injected energy of E≈ 330MJ; (iii) 7 keV Te≈ Ti ITB plasmas at low toroidal rotation, and (iv) wide radius ITB's (r/a=0.6). Furthermore, emphasis in JET is placed on (i) mitigating the impact of ELMs, (ii) understanding the phenomena leading to tritium retention and (iii) preparing burning plasma physics. Recent developments on JET in view of ITER are : (i) real-time control in both ELMy H-Mode and ITB plasmas and (ii) an upgrade of JET with: (a) increased NBI power (b) a new ELM-resilient ITER-like ICRH antenna (7MW) to be tested in 2006 (c) 16 new and upgraded diagnostics.

  3. Delayed Over-Relaxation for iterative methods

    NASA Astrophysics Data System (ADS)

    Antuono, M.; Colicchio, G.

    2016-09-01

    We propose a variant of the relaxation step used in the most widespread iterative methods (e.g. Jacobi Over-Relaxation, Successive Over-Relaxation) which combines the iteration at the predicted step, namely (n + 1), with the iteration at step (n - 1). We provide a theoretical analysis of the proposed algorithm by applying such a delayed relaxation step to a generic (convergent) iterative scheme. We prove that, under proper assumptions, this significantly improves the convergence rate of the initial iterative method. As a relevant example, we apply the proposed algorithm to the solution of the Poisson equation, highlighting the advantages in comparison with classical iterative models.

  4. ODE System Solver W. Krylov Iteration & Rootfinding

    1991-09-09

    LSODKR is a new initial value ODE solver for stiff and nonstiff systems. It is a variant of the LSODPK and LSODE solvers, intended mainly for large stiff systems. The main differences between LSODKR and LSODE are the following: (a) for stiff systems, LSODKR uses a corrector iteration composed of Newton iteration and one of four preconditioned Krylov subspace iteration methods. The user must supply routines for the preconditioning operations, (b) Within the corrector iteration,more » LSODKR does automatic switching between functional (fixpoint) iteration and modified Newton iteration, (c) LSODKR includes the ability to find roots of given functions of the solution during the integration.« less

  5. Transient Heat Transfer in TCAP Coils

    SciTech Connect

    Steimke, J.L.

    1999-03-09

    The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would have been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0" tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed, quickly

  6. Transient Heat Transfer in TCAP Coils

    SciTech Connect

    Steimke, J.L.

    1999-03-09

    The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would have been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0 tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed, quickly

  7. The predicted coiled-coil domain of myosin 10 forms a novel elongated domain that lengthens the head.

    PubMed

    Knight, Peter J; Thirumurugan, Kavitha; Xu, Yuhui; Wang, Fei; Kalverda, Arnout P; Stafford, Walter F; Sellers, James R; Peckham, Michelle

    2005-10-14

    Myosin 10 contains a region of predicted coiled coil 120 residues long. However, the highly charged nature and pattern of charges in the proximal 36 residues appear incompatible with coiled-coil formation. Circular dichroism, NMR, and analytical ultracentrifugation show that a synthesized peptide containing this region forms a stable single alpha-helix (SAH) domain in solution and does not dimerize to form a coiled coil even at millimolar concentrations. Additionally, electron microscopy of a recombinant myosin 10 containing the motor, the three calmodulin binding domains, and the full-length predicted coiled coil showed that it was mostly monomeric at physiological protein concentration. In dimers the molecules were joined only at their extreme distal ends, and no coiled-coil tail was visible. Furthermore, the neck lengths of both monomers and dimers were much longer than expected from the number of calmodulin binding domains. In contrast, micrographs of myosin 5 heavy meromyosin obtained under the same conditions clearly showed a coiled-coil tail, and the necks were the predicted length. Thus the predicted coiled coil of myosin 10 forms a novel elongated structure in which the proximal region is a SAH domain and the distal region is a SAH domain (or has an unknown extended structure) that dimerizes only at its end. Sequence comparisons show that similar structures may exist in the predicted coiled-coil domains of myosins 6 and 7a and MyoM and could function to increase the size of the working stroke. PMID:16030012

  8. Continued Fractions and Iterative Processes.

    ERIC Educational Resources Information Center

    Bevis, Jean H.; Boal, Jan L.

    1982-01-01

    Continued fractions and associated sequences are viewed to constitute a rich area of study for mathematics students, by supporting instruction on algebraic and computational skills, mathematical induction, convergence of sequences, and interpretation of function graphs. An iterative method of approximating square roots opens suggestions for…

  9. Networking Theories by Iterative Unpacking

    ERIC Educational Resources Information Center

    Koichu, Boris

    2014-01-01

    An iterative unpacking strategy consists of sequencing empirically-based theoretical developments so that at each step of theorizing one theory serves as an overarching conceptual framework, in which another theory, either existing or emerging, is embedded in order to elaborate on the chosen element(s) of the overarching theory. The strategy is…

  10. DIII-D Research in Support of ITER

    SciTech Connect

    Strait, E

    2008-10-14

    DIII-D research is providing key information for the design and operation of ITER. Discharges that simulate ITER operating scenarios in conventional H-mode, advanced inductive, hybrid, and steady state regimes have achieved normalized performance consistent with ITER's goals for fusion performance. Stationary discharges with high {beta}{sub N} and 90% noninductive current that project to Q=5 in ITER have been sustained for a current relaxation time ({approx}2.5 s), and high-beta wall-stabilized discharges with fully non-inductive current drive have been sustained for more than one second. Detailed issues of plasma control have been addressed, including the development of a new large-bore startup scenario for ITER. A broad research program provides the physics basis for predicting the performance of ITER. Recent key results include the discovery that the L-H power threshold is reduced with low neutral beam torque, and the development of a successful model for prediction of the H-mode pedestal height in DIII-D. Research areas with the potential to improve ITER's performance include the demonstration of ELM-free 'QH-mode' discharges with both co and counter-injection, and validation of the predicted torque generated by static, non-axisymmetric magnetic fields. New diagnostics provide detailed benchmarking of turbulent transport codes and direct measurements of the anomalous transport of fast ions by Alfven instabilities. DIII-D research also contributes to the basis for reliable operation in ITER, through active control of the chief performance-limiting instabilities. Recently, ELM suppression with resonant magnetic perturbations has been demonstrated at collisionality similar to ITER's, while simultaneous stabilization of NTMs (by localized current drive) and RWMs (by magnetic feedback) has allowed stable operation at high beta and low rotation. In research aimed at improving the lifetime of material surfaces near the plasma, recent experiments have investigated

  11. Contributed Review: Absolute spectral radiance calibration of fiber-optic shock-temperature pyrometers using a coiled-coil irradiance standard lamp.

    PubMed

    Fat'yanov, O V; Asimow, P D

    2015-10-01

    We describe an accurate and precise calibration procedure for multichannel optical pyrometers such as the 6-channel, 3-ns temporal resolution instrument used in the Caltech experimental geophysics laboratory. We begin with a review of calibration sources for shock temperatures in the 3000-30,000 K range. High-power, coiled tungsten halogen standards of spectral irradiance appear to be the only practical alternative to NIST-traceable tungsten ribbon lamps, which are no longer available with large enough calibrated area. However, non-uniform radiance complicates the use of such coiled lamps for reliable and reproducible calibration of pyrometers that employ imaging or relay optics. Careful analysis of documented methods of shock pyrometer calibration to coiled irradiance standard lamps shows that only one technique, not directly applicable in our case, is free of major radiometric errors. We provide a detailed description of the modified Caltech pyrometer instrument and a procedure for its absolute spectral radiance calibration, accurate to ±5%. We employ a designated central area of a 0.7× demagnified image of a coiled-coil tungsten halogen lamp filament, cross-calibrated against a NIST-traceable tungsten ribbon lamp. We give the results of the cross-calibration along with descriptions of the optical arrangement, data acquisition, and processing. We describe a procedure to characterize the difference between the static and dynamic response of amplified photodetectors, allowing time-dependent photodiode correction factors for spectral radiance histories from shock experiments. We validate correct operation of the modified Caltech pyrometer with actual shock temperature experiments on single-crystal NaCl and MgO and obtain very good agreement with the literature data for these substances. We conclude with a summary of the most essential requirements for error-free calibration of a fiber-optic shock-temperature pyrometer using a high-power coiled tungsten halogen

  12. Contributed Review: Absolute spectral radiance calibration of fiber-optic shock-temperature pyrometers using a coiled-coil irradiance standard lamp

    SciTech Connect

    Fat’yanov, O. V. Asimow, P. D.

    2015-10-15

    We describe an accurate and precise calibration procedure for multichannel optical pyrometers such as the 6-channel, 3-ns temporal resolution instrument used in the Caltech experimental geophysics laboratory. We begin with a review of calibration sources for shock temperatures in the 3000-30 000 K range. High-power, coiled tungsten halogen standards of spectral irradiance appear to be the only practical alternative to NIST-traceable tungsten ribbon lamps, which are no longer available with large enough calibrated area. However, non-uniform radiance complicates the use of such coiled lamps for reliable and reproducible calibration of pyrometers that employ imaging or relay optics. Careful analysis of documented methods of shock pyrometer calibration to coiled irradiance standard lamps shows that only one technique, not directly applicable in our case, is free of major radiometric errors. We provide a detailed description of the modified Caltech pyrometer instrument and a procedure for its absolute spectral radiance calibration, accurate to ±5%. We employ a designated central area of a 0.7× demagnified image of a coiled-coil tungsten halogen lamp filament, cross-calibrated against a NIST-traceable tungsten ribbon lamp. We give the results of the cross-calibration along with descriptions of the optical arrangement, data acquisition, and processing. We describe a procedure to characterize the difference between the static and dynamic response of amplified photodetectors, allowing time-dependent photodiode correction factors for spectral radiance histories from shock experiments. We validate correct operation of the modified Caltech pyrometer with actual shock temperature experiments on single-crystal NaCl and MgO and obtain very good agreement with the literature data for these substances. We conclude with a summary of the most essential requirements for error-free calibration of a fiber-optic shock-temperature pyrometer using a high-power coiled tungsten halogen

  13. Contributed Review: Absolute spectral radiance calibration of fiber-optic shock-temperature pyrometers using a coiled-coil irradiance standard lamp.

    PubMed

    Fat'yanov, O V; Asimow, P D

    2015-10-01

    We describe an accurate and precise calibration procedure for multichannel optical pyrometers such as the 6-channel, 3-ns temporal resolution instrument used in the Caltech experimental geophysics laboratory. We begin with a review of calibration sources for shock temperatures in the 3000-30,000 K range. High-power, coiled tungsten halogen standards of spectral irradiance appear to be the only practical alternative to NIST-traceable tungsten ribbon lamps, which are no longer available with large enough calibrated area. However, non-uniform radiance complicates the use of such coiled lamps for reliable and reproducible calibration of pyrometers that employ imaging or relay optics. Careful analysis of documented methods of shock pyrometer calibration to coiled irradiance standard lamps shows that only one technique, not directly applicable in our case, is free of major radiometric errors. We provide a detailed description of the modified Caltech pyrometer instrument and a procedure for its absolute spectral radiance calibration, accurate to ±5%. We employ a designated central area of a 0.7× demagnified image of a coiled-coil tungsten halogen lamp filament, cross-calibrated against a NIST-traceable tungsten ribbon lamp. We give the results of the cross-calibration along with descriptions of the optical arrangement, data acquisition, and processing. We describe a procedure to characterize the difference between the static and dynamic response of amplified photodetectors, allowing time-dependent photodiode correction factors for spectral radiance histories from shock experiments. We validate correct operation of the modified Caltech pyrometer with actual shock temperature experiments on single-crystal NaCl and MgO and obtain very good agreement with the literature data for these substances. We conclude with a summary of the most essential requirements for error-free calibration of a fiber-optic shock-temperature pyrometer using a high-power coiled tungsten halogen

  14. Contributed Review: Absolute spectral radiance calibration of fiber-optic shock-temperature pyrometers using a coiled-coil irradiance standard lamp

    NASA Astrophysics Data System (ADS)

    Fat'yanov, O. V.; Asimow, P. D.

    2015-10-01

    We describe an accurate and precise calibration procedure for multichannel optical pyrometers such as the 6-channel, 3-ns temporal resolution instrument used in the Caltech experimental geophysics laboratory. We begin with a review of calibration sources for shock temperatures in the 3000-30 000 K range. High-power, coiled tungsten halogen standards of spectral irradiance appear to be the only practical alternative to NIST-traceable tungsten ribbon lamps, which are no longer available with large enough calibrated area. However, non-uniform radiance complicates the use of such coiled lamps for reliable and reproducible calibration of pyrometers that employ imaging or relay optics. Careful analysis of documented methods of shock pyrometer calibration to coiled irradiance standard lamps shows that only one technique, not directly applicable in our case, is free of major radiometric errors. We provide a detailed description of the modified Caltech pyrometer instrument and a procedure for its absolute spectral radiance calibration, accurate to ±5%. We employ a designated central area of a 0.7× demagnified image of a coiled-coil tungsten halogen lamp filament, cross-calibrated against a NIST-traceable tungsten ribbon lamp. We give the results of the cross-calibration along with descriptions of the optical arrangement, data acquisition, and processing. We describe a procedure to characterize the difference between the static and dynamic response of amplified photodetectors, allowing time-dependent photodiode correction factors for spectral radiance histories from shock experiments. We validate correct operation of the modified Caltech pyrometer with actual shock temperature experiments on single-crystal NaCl and MgO and obtain very good agreement with the literature data for these substances. We conclude with a summary of the most essential requirements for error-free calibration of a fiber-optic shock-temperature pyrometer using a high-power coiled tungsten halogen

  15. Tooling concepts for ITER tokamak assembly and remote disassembly

    SciTech Connect

    Oikawa, A.; Puhn, F.; Helary, J.L.; Shaw, R.; Friend, M.; Piec, Z.; Tachikawa, N.; Acks, M.; Basile, A.

    1995-12-31

    Since ITER has many of the characteristics of a full-scale tokamak reactor, its provisions for assembly and replaceability are relevant to a future fusion power plant. The performance of ITER is dependent on tight tolerances, mainly for the magnets and plasma facing components. The magnetic field must be highly uniform in the toroidal direction to ensure good plasma energy and particle confinement. Alignment of the plasma facing surface of the first wall and divertor target plates is required to avoid large local heat loads on the plasma facing components and, as a consequence, their erosion and contamination of the plasma with impurities. Because of the large and heavy components the major challenge of the ITER tokamak assembly is to hold such tight tolerances using guide tools, adjustable interfaces, accurate measuring tools, and specific procedures to compensate for deformation and fabrication tolerances. The assembly tooling plan also includes verification of the essential remote handling operations.

  16. Active beam spectroscopy for ITER

    NASA Astrophysics Data System (ADS)

    von Hellermann, M. G.; Barnsley, R.; Biel, W.; Delabie, E.; Hawkes, N.; Jaspers, R.; Johnson, D.; Klinkhamer, F.; Lischtschenko, O.; Marchuk, O.; Schunke, B.; Singh, M. J.; Snijders, B.; Summers, H. P.; Thomas, D.; Tugarinov, S.; Vasu, P.

    2010-11-01

    Since the first feasibility studies of active beam spectroscopy on ITER in 1995 the proposed diagnostic has developed into a well advanced and mature system. Substantial progress has been achieved on the physics side including comprehensive performance studies based on an advanced predictive code, which simulates active and passive features of the expected spectral ranges. The simulation has enabled detailed specifications for an optimized instrumentation and has helped to specify suitable diagnostic neutral beam parameters. Four ITER partners share presently the task of developing a suite of ITER active beam diagnostics, which make use of the two 0.5 MeV/amu 18 MW heating neutral beams and a dedicated 0.1 MeV/amu, 3.6 MW diagnostic neutral beam. The IN ITER team is responsible for the DNB development and also for beam physics related aspects of the diagnostic. The RF will be responsible for edge CXRS system covering the outer region of the plasma (1> r/ a>0.4) using an equatorial observation port, and the EU will develop the core CXRS system for the very core (0< r/ a<0.7) using a top observation port. Thus optimum radial resolution is ensured for each system with better than a/30 resolution. Finally, the US will develop a dedicated MSE system making use of the HNBs and two equatorial ports. With appropriate modification, these systems could also potentially provide information on alpha particle slowing-down features. . On the engineering side, comprehensive preparations were made involving the development of an observation periscope, a neutron labyrinth optical system and design studies for remote maintenance including the exchange of the first mirror assembly, a critical issue for the operation of the CXRS diagnostic in the harsh ITER environment. Additionally, an essential change of the orientation of the DNB injection angle and specification of suitable blanket aperture has been made to avoid trapped particle damage to the first wall.

  17. Quench Protection of DI-BSCCO Coil

    NASA Astrophysics Data System (ADS)

    Yamaguchi, T.; Ueno, E.; Kato, T.; Hayashi, K.

    Quench protection is one of the most important requirements for the practical application of high-temperature-superconducting (HTS) coils. Quench protection requires that early detection of a developing quench event is followed by rapid reduction of the operating current. However, such quench detection is very difficult because HTS wire produces heat only locally due to the very slow propagation velocity of a normal zone. Excellent high voltage insulation performance is required if the current is to be reduced rapidly in a large-scale superconducting application with very large inductance. Thus it is important to investigate the behavior of coils with various decay time constants, and to detect voltages on very short time scales. This goal remains to be achieved. In the present study we built test coil and a full-scale pole coil for a 20 MW motor for use in experiments on quench protection, and parameterized the relation between the decay time constant and the detecting voltage, using a conventional balance circuit to detect the quench, which was generated by gradually raising the temperature of the coils. The results verify that a balance circuit can be used for quench detection. For example, when the current decay time constant is 4 seconds, the test coil can be protected even with a detecting voltage of 0.15 volts, despite a significant heat production rate of 126 W. We also confirmed that the full-scale pole coil, with a decay time constant of 20 seconds, can be protected with a detecting voltage of 0.06 V.

  18. Mechanical Properties of High Manganese Austenitic Stainless Steel JK2LB for ITER Central Solenoid Jacket Material

    NASA Astrophysics Data System (ADS)

    Saito, Toru; Kawano, Katsumi; Yamazaki, Toru; Ozeki, Hidemasa; Isono, Takaaki; Hamada, Kazuya; Devred, Arnaud; Vostner, Alexander

    A suite of advanced austenitic stainless steels are used for the ITER TF, CS and PF coil systems.These materials will be exposed to cyclic-stress at cryogenic temperature. Therefore, high manganese austenitic stainless steel JK2LB, which has high tensile strength, high ductility and high resistance to fatigue at 4 K has been chosen for the CS conductor. The cryogenic temperature mechanical property data of this material are very important for the ITER magnet design. This study is focused on mechanical characteristics of JK2LB and its weld joint.

  19. Design and Fabrication of Helmholtz Coils to Study the Effects of Pulsed Electromagnetic Fields on the Healing Process in Periodontitis: Preliminary Animal Results

    PubMed Central

    Haghnegahdar, A; Khosrovpanah, H; Andisheh-Tadbir, A; Mortazavi, Gh; Saeedi Moghadam, M; Mortazavi, SMJ; Zamani, A; Haghani, M; Shojaei Fard, M; Parsaei, H; Koohi, O

    2014-01-01

    Background: Effects of electromagnetic fields on healing have been investigated for centuries. Substantial data indicate that exposure to electromagnetic field can lead to enhanced healing in both soft and hard tissues. Helmholtz coils are devices that generate pulsed electromagnetic fields (PEMF). Objective: In this work, a pair of Helmholtz coils for enhancing the healing process in periodontitis was designed and fabricated. Method: An identical pair of square Helmholtz coils generated the 50 Hz magnetic field.  This device was made up of two parallel coaxial circular coils (100 turns in each loop, wound in series) which were separated from each other by a distance equal to the radius of one coil (12.5 cm). The windings of our Helmholtz coil was made of standard 0.95mm wire to provide the maximum possible current. The coil was powered by a function generator.  Results: The Helmholtz Coils generated a uniform magnetic field between its coils. The magnetic field strength at the center of the space between two coils was 97.6 μT. Preliminary biological studies performed on rats show that exposure of laboratory animals to pulsed electromagnetic fields enhanced the healing of periodontitis. Conclusion: Exposure to PEMFs can lead to stimulatory physiological effects on cells and tissues such as enhanced healing of periodontitis. PMID:25505775

  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

    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.

  2. 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. PMID:23902112

  3. Growth Factor Tethering to Protein Nanoparticles via Coiled-Coil Formation for Targeted Drug Delivery.

    PubMed

    Assal, Yasmine; Mizuguchi, Yoshinori; Mie, Masayasu; Kobatake, Eiry

    2015-08-19

    Protein-based nanoparticles are attractive carriers for drug delivery because they are biodegradable and can be genetically designed. Moreover, modification of protein-based nanoparticles with cell-specific ligands allows for active targeting abilities. Previously, we developed protein nanoparticles comprising genetically engineered elastin-like polypeptides (ELPs) with fused polyaspartic acid tails (ELP-D). Epidermal growth factor (EGF) was displayed on the surface of the ELP-D nanoparticles via genetic design to allow for active cell-targeting abilities. Herein, we focused on the coiled-coil structural motif as a means for noncovalent tethering of growth factor to ELP-D. Specifically, two peptides known to form a heterodimer via a coiled-coil structural motif were fused to ELP-D and single-chain vascular endothelial growth factor (scVEGF121), to facilitate noncovalent tethering upon formation of the heterodimer coiled-coil structure. Drug-loaded growth factor-tethered ELP-Ds were found to be effective against cancer cells by provoking cell apoptosis. These results demonstrate that tethering growth factor to protein nanoparticles through coiled-coil formation yields a promising biomaterial candidate for targeted drug delivery.

  4. A coiled-coil domain acts as a molecular ruler in LPS chain length regulation

    PubMed Central

    Tuukkanen, Anne; Danciu, Iulia; Svergun, Dmitri I.; Hussain, Rohanah; Liu, Huanting; Whitfield, Chris; Naismith, James H.

    2014-01-01

    Long-chain bacterial polysaccharides play important roles in pathogenicity. In Escherichia coli O9a, a model for ABC transporter dependent polysaccharide assembly, a large extracellular carbohydrate with a narrow distribution of size is polymerized from monosaccharides by a complex of two proteins, WbdA (polymerase) and WbdD (terminating protein). Such careful control of polymerization is recurring theme in biology. Combining crystallography and small angle X-ray scattering, we show that the C-terminal domain of WbdD contains an extended coiled-coil that physically separates WbdA from the catalytic domain of WbdD. The effects of insertions and deletions within the coiled-coil region were analyzed in vivo, revealing that polymer size is controlled by varying the length of the coiled-coil domain. Thus, the coiled-coil domain of WbdD functions as a molecular ruler that, along with WbdA:WbdD stoichiometry, controls the chain length of a model bacterial polysaccharide. PMID:25504321

  5. Forced Unfolding of the Coiled-Coils of Fibrinogen by Single-Molecule AFM

    NASA Astrophysics Data System (ADS)

    Brown, Andre; Litvinov, Rustem; Discher, Dennis; Weisel, John

    2007-03-01

    A blood clot needs to have the right degree of stiffness and plasticity for hemostasis, but the origin of these mechanical properties is unknown. Here we report the first measurements using single molecule atomic force microscopy (AFM) to study the forced unfolding of fibrinogen to begin addressing this problem. To generate longer reproducible curves than are possible using monomer, factor XIIIa cross-linked, single chain fibrinogen oligomers were used. When extended under force, these oligomers showed sawtooth shaped force-extension patterns characteristic of unfolding proteins with a peak-to-peak separation of approximately 26 nm, consistent with the independent unfolding of the coiled-coils. These results were then reproduced using a Monte Carlo simulation with parameters in the same range as those previously used for unfolding globular domains. In particular, we found that the refolding time was negligible on experimental time and force scales in contrast to previous work on simpler coiled-coils. We suggest that this difference may be due to fibrinogen's structurally and topologically more complex coiled-coils and that an interaction between the alpha C and central domains may be involved. These results suggest a new functional property of fibrinogen and that the coiled-coil is more than a passive structural element of this molecule.

  6. Antiparallel Four-Stranded Coiled Coil Specified by a 3-3-1 Hyrdrophobic Heptad Repeat

    SciTech Connect

    Deng,Y.; Liu, J.; Zheng, Q.; Eliezer, D.; Kallenbach, N.; Lu, M.

    2006-01-01

    Coiled-coil sequences in proteins commonly share a seven-amino acid repeat with nonpolar side chains at the first (a) and fourth (d) positions. We investigate here the role of a 3-3-1 hydrophobic repeat containing nonpolar amino acids at the a, d, and g positions in determining the structures of coiled coils using mutants of the GCN4 leucine zipper dimerization domain. When three charged residues at the g positions in the parental sequence are replaced by nonpolar alanine or valine side chains, stable four-helix structures result. The X-ray crystal structures of the tetramers reveal antiparallel, four-stranded coiled coils in which the a, d, and g side chains interlock in a combination of knobs-into-knobs and knobs-into-holes packing. Interfacial interactions in a coiled coil can therefore be prescribed by hydrophobic-polar patterns beyond the canonical 3-4 heptad repeat. The results suggest that the conserved, charged residues at the g positions in the GCN4 leucine zipper can impart a negative design element to disfavor thermodynamically more stable, antiparallel tetramers.

  7. Laser cleaning of ITER's diagnostic mirrors

    NASA Astrophysics Data System (ADS)

    Skinner, C. H.; Gentile, C. A.; Doerner, R.

    2012-10-01

    Practical methods to clean ITER's diagnostic mirrors and restore reflectivity will be critical to ITER's plasma operations. We report on laser cleaning of single crystal molybdenum mirrors coated with either carbon or beryllium films 150 - 420 nm thick. A 1.06 μm Nd laser system provided 220 ns pulses at 8 kHz with typical power densities of 1-2 J/cm^2. The laser beam was fiber optically coupled to a scanner suitable for tokamak applications. The efficacy of mirror cleaning was assessed with a new technique that combines microscopic imaging and reflectivity measurements [1]. The method is suitable for hazardous materials such as beryllium as the mirrors remain sealed in a vacuum chamber. Excellent restoration of reflectivity for the carbon coated Mo mirrors was observed after laser scanning under vacuum conditions. For the beryllium coated mirrors restoration of reflectivity has so far been incomplete and modeling indicates that a shorter duration laser pulse is needed. No damage of the molybdenum mirror substrates was observed.[4pt][1] C.H. Skinner et al., Rev. Sci. Instrum. at press.

  8. Nuclear Analysis of an ITER Blanket Module

    NASA Astrophysics Data System (ADS)

    Chiovaro, P.; Di Maio, P. A.; Parrinello, V.

    2013-08-01

    ITER blanket system is the reactor's plasma-facing component, it is mainly devoted to provide the thermal and nuclear shielding of the Vacuum Vessel and external ITER components, being intended also to act as plasma limiter. It consists of 440 individual modules which are located in the inboard, upper and outboard regions of the reactor. In this paper attention has been focused on to a single outboard blanket module located in the equatorial zone, whose nuclear response under irradiation has been investigated following a numerical approach based on the Monte Carlo method and adopting the MCNP5 code. The main features of this blanket module nuclear behaviour have been determined, paying particular attention to energy and spatial distribution of the neutron flux and deposited nuclear power together with the spatial distribution of its volumetric density. Moreover, the neutronic damage of the structural material has also been investigated through the evaluation of displacement per atom and helium and hydrogen production rates. Finally, an activation analysis has been performed with FISPACT inventory code using, as input, the evaluated neutron spectrum to assess the module specific activity and contact dose rate after irradiation under a specific operating scenario.

  9. Basic cooling characteristics of perfluorocarbon liquid immersed windings for nonflammable transformers; Disk coil cooling for large-capacity forced circulating transformers. Part 1

    SciTech Connect

    Yamazaki, H.; Sakamoto, T. ); Takagi, I. )

    1991-01-01

    This paper reports that to develop a new type of nonflammable large-power transformer which uses perfluorocarbon liquid as the cooling and insulation medium, the basic cooling characteristics of the liquid were investigated. Using a horizontal coil duct model, design data on heat-transfer characteristics of perfluorocarbon liquid were obtained by the computer program. Using a two-dimensional cooling model of nine coils per section, the velocity distribution in the coil ducts and the temperature rise distribution of the coils were clarified. Comparisons were made between experimental and calculated results and the developed computer program was found to be valid for the prediction of the velocity distribution in the coil ducts and of the temperature rise distribution of the coils.

  10. Two-slot coiled coaxial cable resonator: reaching critical coupling at a reduced number of coils.

    PubMed

    Hefferman, Gerald; Chen, Zhen; Wei, Tao

    2014-11-01

    This paper reports the experimental demonstration of a coiled coaxial cable resonator capable of meeting the critical coupling condition using a reduced number of coils relative to previously reported coiled resonators. By introducing a second slot along the length of the device, a two-slot coiled coaxial cable resonator was fabricated and critical coupling observed at 22 turns. An additional device with one-slot, but otherwise identically constructed, was also fabricated. After 44 turns, the one-slot device had yet to reach critical coupling. An ultrahigh signal-to-noise ratio (greater than 70 dB) was observed at critical coupling of the two-slot device. This reduction in number of slots necessary to reach critical coupling, and the corresponding reduction of physical length of the device, makes this demonstration of the control of critical coupling a potentially important step towards the successful application of coiled coaxial cable resonators to microwave communication and robust sensing applications.

  11. Coil in coil - components for the high voltage superconducting resistive current limiter CULT 110

    NASA Astrophysics Data System (ADS)

    Elschner, S.; Stemmle, M.; Breuer, F.; Walter, H.; Frohne, C.; Noe, M.; Bock, J.

    2008-02-01

    The German government (BMBF/VDI) funded project CULT 110 is presently the largest European current limiter project and aims at the development of a one-phase resistive limiter for the voltage level of 110 kV. The contribution presents the actual state of development of the superconducting components. As in the successful predecessor project CURL 10 these are made of melt cast processed BSCCO 2212 bulk material, however monofilar instead of bifilar coils are used. The electrical protection concept is based on a normal conducting coil arranged around a superconducting coil and connected in parallel. Simultaneously this coil serves as an electrical bypass and, under fault conditions, generates a magnetic field for quench homogenisation. Since no continuously connected shunt is needed, a much higher voltage during faults can be applied. The rules for an optimum superconductor and coil design are given and the viability of the whole concept is demonstrated by both, experiment and numerical simulation.

  12. Modulation of elasticity in functionally distinct domains of the tropomyosin coiled-coil

    PubMed Central

    Lakkaraju, Sirish Kaushik; Hwang, Wonmuk

    2009-01-01

    Alpha-helical coiled-coils are common protein structural motifs. Whereas vast information is available regarding their structure, folding, and stability, far less is known about their elastic properties, even though they play mechanical roles in many cases such as tropomyosin in muscle contraction or neck stalks of kinesin or myosin motor proteins. Using computer simulations, we characterized elastic properties of coiled-coils, either globally or locally. Global bending stiffness of standard leucine zipper coiled-coils was calculated using normal mode analysis. Mutations in hydrophobic residues involved in the knob-into-hole interface between the two α-helices affect elasticity significantly, whereas charged side chains forming inter-helical salt bridges do not. This suggests that coiled-coils with less regular heptad periodicity may have regional variations in flexibility. We show this by the flexibility map of tropomyosin, which was constructed by a local fluctuation analysis. Overall, flexibility varies by more than twofold and increases towards the C-terminal region of the molecule. Describing the coiled-coil as a twisted tape, it is generally more flexible in the splay bending than in the bending of the broad face. Actin binding sites in α zones show local rigidity minima. Broken core regions due to acidic residues at the hydrophobic face such as the Asp137 and the Glu218 are found to be the most labile with moduli for splay and broad face bending as 70 nm and 116 nm respectively. Such variation in flexibility could be relevant to the tropomyosin function, especially for moving across the non-uniform surface of F-actin to regulate myosin binding. PMID:19830262

  13. STELLOPT modeling of the 3D diagnostic response in ITER

    NASA Astrophysics Data System (ADS)

    Lazerson, S. A.; Chapman, I. T.

    2013-08-01

    The ITER three-dimensional (3D) diagnostic response to an n = 3 resonant magnetic perturbation (RMP) is modeled using the STELLOPT code. The in-vessel coils apply a RMP field which generates a 4 cm edge displacement from axisymmetry as modeled by the VMEC 3D equilibrium code. Forward modeling of flux loop and magnetic probe response with the DIAGNO code indicates up to 20% changes in measured plasma signals. Simulated LIDAR measurements of electron temperature indicate 2 cm shifts on the low-field side of the plasma. This suggests that the ITER diagnostic will be able to diagnose the 3D structure of the equilibria. Notice: This paper has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the US Department of Energy. The publisher, by accepting the paper for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this Paper, or allow others to do so, for United States Government purposes.

  14. Progress on an ITER ECH Transmission system development and testing

    NASA Astrophysics Data System (ADS)

    Bigelow, Tim; Hanson, Greg; Rasmussen, Dave; Barker, Alan; Dukes, Carl; Killough, Stephen; Peters, Brian; Rumbolt, Robin; Schaich, Chuck; Sanabria, Roberto; McElehaney, Karen; White, John; Allison, Stephen

    2012-10-01

    Progress on further development of the ITER ECH Transmission system design and testing of waveguide components will be presented. Work on the preliminary design of the system configuration is proceeding based on the conceptual design from the ITER Organization. Requirements for precision of waveguide supports and components are being analyzed and thermal and mechanical modeling of prototype components is being performed. Several prototype components have been procured from industry and some have been tested to nearly 1 MW at 170 GHz for long pulses at JAEA in Japan. A high power test stand is being developed at ORNL to provide component, system, and instrumentation tests at 1 MW cw or higher power conditions. The high voltage power supply has been tested and 140 GHz and 170 GHz gyrotrons are expected to be operational in the near future.

  15. Recommendations for a cryogenic system for ITER (International Thermonuclear Experimental Reactor)

    SciTech Connect

    Slack, D.S.

    1989-09-20

    The International Thermonuclear Experimental Reactor (ITER) is a new tokamak design project with joint participation from Japan, the European Community, the Soviet Union, and the United States. ITER will be a large machine requiring up to 100 kW of refrigeration at 4.5 K to cool its superconducting magnets. Unlike earlier fusion experiments, the ITER cryogenic system must handle pulse loads constituting a large percentage of the total load. These come from neutron heating during a fusion burn and from ac losses during ramping of current in the PF (poloidal field) coils. This paper presents a conceptual design for a cryogenic system that meets ITER requirements. It describes a system with the following features: Only time-proven components are used. The system obtains a high efficiency without use of cold pumps or other developmental components. High reliability is achieved by paralleling compressors and expanders and by using adequate isolation valving. The problem of load fluctuations is solved by a simple load-leveling device. The cryogenic system can be housed in a separate building located at a considerable distance from the ITER core, if desired. The paper also summarizes physical plant size, cost estimates, and means of handling vented helium during magnet quench. 4 refs., 4 figs., 3 tabs.

  16. Improved criticality convergence via a modified Monte Carlo iteration method

    SciTech Connect

    Booth, Thomas E; Gubernatis, James E

    2009-01-01

    Nuclear criticality calculations with Monte Carlo codes are normally done using a power iteration method to obtain the dominant eigenfunction and eigenvalue. In the last few years it has been shown that the power iteration method can be modified to obtain the first two eigenfunctions. This modified power iteration method directly subtracts out the second eigenfunction and thus only powers out the third and higher eigenfunctions. The result is a convergence rate to the dominant eigenfunction being |k{sub 3}|/k{sub 1} instead of |k{sub 2}|/k{sub 1}. One difficulty is that the second eigenfunction contains particles of both positive and negative weights that must sum somehow to maintain the second eigenfunction. Summing negative and positive weights can be done using point detector mechanics, but this sometimes can be quite slow. We show that an approximate cancellation scheme is sufficient to accelerate the convergence to the dominant eigenfunction. A second difficulty is that for some problems the Monte Carlo implementation of the modified power method has some stability problems. We also show that a simple method deals with this in an effective, but ad hoc manner.

  17. A PIN diode controlled dual-tuned MRI RF coil and phased array for multi nuclear imaging

    NASA Astrophysics Data System (ADS)

    Ha, Seunghoon; Hamamura, Mark J.; Nalcioglu, Orhan; Tugan Muftuler, L.

    2010-05-01

    MR imaging of nuclei other than hydrogen has been used to investigate metabolism in humans and animals. However, MRI observable nuclei other than hydrogen are not as abundant and as a result the image SNR is lower. Dual-tuned radio frequency (RF) coils are developed for these studies in which high-resolution structural images are acquired using hydrogen and metabolic information is acquired by exciting the other nucleus. Using a dual-tuned coil, the experimenter avoids the inconvenience of moving the patient out and replacing the RF coil for imaging different nuclei. This also eliminates image registration problems. However, the common scheme of using trap circuits for dual-tuned operation results in increased coil losses as well as problems in obtaining optimal tuning and matching at both frequencies. Here, a new approach is presented using PIN diodes to switch the coil between two resonance frequencies. This design eliminates the need for the trap circuit and associated losses from the self-resistance of the trap circuit inductors. At the operating frequencies we used, the equivalent series resistance of an inductor is higher than that of the PIN diodes. In order to test the efficacy of this new approach, we first built two surface coils of identical geometry, one with the conventional trap circuits and one with the PIN diode switches. We also studied the performances of both coils when the coils are divided into shorter conductors segments by adding more tuning elements. It is known that dividing the coil into shorter conductor segments helps reduce radiation and electric field losses. We explored this effect for both coils at both operating frequencies. Finally, a dual-tuned receive-only phased array was designed and built with the PIN diode circuit to switch between two resonance frequencies. A conventional dual-tuned birdcage coil was designed and built to transmit RF power. A unique feature of this coil is that the RF power is fed through two separate sets

  18. A PIN diode controlled dual-tuned MRI RF coil and phased array for multi nuclear imaging.

    PubMed

    Ha, Seunghoon; Hamamura, Mark J; Nalcioglu, Orhan; Muftuler, L Tugan

    2010-05-01

    MR imaging of nuclei other than hydrogen has been used to investigate metabolism in humans and animals. However, MRI observable nuclei other than hydrogen are not as abundant and as a result the image SNR is lower. Dual-tuned radio frequency (RF) coils are developed for these studies in which high-resolution structural images are acquired using hydrogen and metabolic information is acquired by exciting the other nucleus. Using a dual-tuned coil, the experimenter avoids the inconvenience of moving the patient out and replacing the RF coil for imaging different nuclei. This also eliminates image registration problems. However, the common scheme of using trap circuits for dual-tuned operation results in increased coil losses as well as problems in obtaining optimal tuning and matching at both frequencies. Here, a new approach is presented using PIN diodes to switch the coil between two resonance frequencies. This design eliminates the need for the trap circuit and associated losses from the self-resistance of the trap circuit inductors. At the operating frequencies we used, the equivalent series resistance of an inductor is higher than that of the PIN diodes. In order to test the efficacy of this new approach, we first built two surface coils of identical geometry, one with the conventional trap circuits and one with the PIN diode switches. We also studied the performances of both coils when the coils are divided into shorter conductors segments by adding more tuning elements. It is known that dividing the coil into shorter conductor segments helps reduce radiation and electric field losses. We explored this effect for both coils at both operating frequencies. Finally, a dual-tuned receive-only phased array was designed and built with the PIN diode circuit to switch between two resonance frequencies. A conventional dual-tuned birdcage coil was designed and built to transmit RF power. A unique feature of this coil is that the RF power is fed through two separate sets

  19. Conceptual Design and Analysis of Cold Mass Support of the CS3U Feeder for the ITER

    NASA Astrophysics Data System (ADS)

    Zhu, Yinfeng; Song, Yuntao; Zhang, Yuanbin; Wang, Zhongwei

    2013-06-01

    In the International Thermonuclear Experimental Reactor (ITER) project, the feeders are one of the most important and critical systems. To convey the power supply and the coolant for the central solenoid (CS) magnet, 6 sets of CS feeders are employed, which consist mainly of an in-cryostat feeder (ICF), a cryostat feed-through (CFT), an S-bend box (SBB), and a coil terminal box (CTB). To compensate the displacements of the internal components of the CS feeders during operation, sliding cold mass supports consisting of a sled plate, a cylindrical support, a thermal shield, and an external ring are developed. To check the strength of the developed cold mass supports of the CS3U feeder, electromagnetic analysis of the two superconducting busbars is performed by using the CATIA V5 and ANSYS codes based on parametric technology. Furthermore, the thermal-structural coupling analysis is performed based on the obtained results, except for the stress concentration, and the max. stress intensity is lower than the allowable stress of the selected material. It is found that the conceptual design of the cold mass support can satisfy the required functions under the worst case of normal working conditions. All these performed activities will provide a firm technical basis for the engineering design and development of cold mass supports.

  20. L-H transition studies on DIII-D to determine H-mode access for operational scenarios in ITER

    SciTech Connect

    Gohil, P.; Evans, T.E.; Fenstermacher, M; Ferron, J.R.; Osborne, T.H.; Schmitz, O.; Scoville, J. T.

    2011-01-01

    A comprehensive set of L-H transition experiments has been performed on DIII-D to determine the requirements for access to H-mode plasmas in ITER's first (non-nuclear) operational phase with H and He plasmas and the second (activated) operational phase with D plasmas. The H-mode power threshold, P(TH), was evaluated for different operational configurations and auxiliary heating methods for the different main ion species. Helium plasmas have significantly higher P(TH) than deuterium plasmas at low densities for all heating schemes, but similar P(TH) as deuterium plasmas at high densities except for H-neutral beam injection-heated discharges, which are still higher. Changes in P(TH) are observed when helium concentration levels in deuterium plasmas exceed 40%. There is a strong dependence of P(TH) on the magnetic geometry in the vicinity of the divertor. The trend of decreasing P(TH) with decreasing X-point height is observed for all of the main ion species irrespective of the heating method, which appears to indicate that there is a common physics process behind this effect for all of the ion species. Helium and deuterium plasmas exhibit a significant increase in P(TH) for strong resonant magnetic perturbations. The application of a local magnetic ripple of 3% from test blanket module mock-up coils did not change P(TH) in deuterium plasmas.