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Sample records for preliminary iter magnet

  1. Engineering, Manufacture and Preliminary Testing of the ITER Toroidal Field (TF) Magnet Helium Cold Circulator

    Science.gov (United States)

    Rista, P. E. C.; Shull, J.; Sargent, S.

    2015-12-01

    The ITER cryodistribution system provides the supercritical Helium (SHe) forced flow cooling to the magnet system using cold circulators. The cold circulators are located in each of five separate auxiliary cold boxes planned for use in the facility. Barber-Nichols Inc. has been awarded a contract from ITER-India for engineering, manufacture and testing of the Toroidal Field (TF) Magnet Helium Cold Circulator. The cold circulator will be extensively tested at Barber-Nichols’ facility prior to delivery for qualification testing at the Japan Atomic Energy Agency's (JAEA) test facility at Naka, Japan. The TF Cold Circulator integrates features and technical requirements which Barber-Nichols has utilized when supplying helium cold circulators worldwide over a period of 35 years. Features include a vacuum-jacketed hermetically sealed design with a very low helium leak rate, a heat shield for use with both nitrogen & helium cold sources, a broad operating range with a guaranteed isentropic efficiency over 70%, and impeller design features for high efficiency. The cold circulator will be designed to meet MTBM of 17,500 hours and MTBF of 36,000 hours. Vibration and speed monitoring are integrated into a compact package on the rotating assembly with operation and health monitoring in a multi-drop PROFIBUS communication environment using an electrical cabinet with critical features and full local and network PLC interface and control. For the testing in Japan and eventual installation in Europe, the cold circulator must be certified to the Japanese High Pressure Gas Safety Act (JHPGSA) and CE marked in compliance with the European Pressure Equipment Directive (PED) including Essential Safety Requirements (ESR). The test methodology utilized at Barber-Nichols’ facility and the resulting test data, validating the high efficiency of the TF Cold Circulator across a broad operating range, are important features of this paper.

  2. Cryogenic instrumentation for ITER magnets

    Science.gov (United States)

    Poncet, J.-M.; Manzagol, J.; Attard, A.; André, J.; Bizel-Bizellot, L.; Bonnay, P.; Ercolani, E.; Luchier, N.; Girard, A.; Clayton, N.; Devred, A.; Huygen, S.; Journeaux, J.-Y.

    2017-02-01

    Accurate measurements of the helium flowrate and of the temperature of the ITER magnets is of fundamental importance to make sure that the magnets operate under well controlled and reliable conditions, and to allow suitable helium flow distribution in the magnets through the helium piping. Therefore, the temperature and flow rate measurements shall be reliable and accurate. In this paper, we present the thermometric chains as well as the venturi flow meters installed in the ITER magnets and their helium piping. The presented thermometric block design is based on the design developed by CERN for the LHC, which has been further optimized via thermal simulations carried out by CEA. The electronic part of the thermometric chain was entirely developed by the CEA and will be presented in detail: it is based on a lock-in measurement and small signal amplification, and also provides a web interface and software to an industrial PLC. This measuring device provides a reliable, accurate, electromagnetically immune, and fast (up to 100 Hz bandwidth) system for resistive temperature sensors between a few ohms to 100 kΩ. The flowmeters (venturi type) which make up part of the helium mass flow measurement chain have been completely designed, and manufacturing is on-going. The behaviour of the helium gas has been studied in detailed thanks to ANSYS CFX software in order to obtain the same differential pressure for all types of flowmeters. Measurement uncertainties have been estimated and the influence of input parameters has been studied. Mechanical calculations have been performed to guarantee the mechanical strength of the venturis required for pressure equipment operating in nuclear environment. In order to complete the helium mass flow measurement chain, different technologies of absolute and differential pressure sensors have been tested in an applied magnetic field to identify equipment compatible with the ITER environment.

  3. Magnetic configuration control of ITER plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Albanese, R.; Mattei, M. [Assoc. Euratom-ENEA-CREATE, Univ. Mediterranea RC, Loc. Feo di Vito I-89060, RC (Italy); Portone, A. [EFDA-CSU, Max Planck Institute for Plasmaphysics, Boltzmannstrasse 2, D-85748 Garching (Germany)], E-mail: alfredo.portone@tech.efda.org; Ambrosino, G. [Assoc. Euratom-ENEA-CREATE, University Napoli Federico II, Via Claudio 21, I-80125 Naples (Italy); Artaserse, G. [Assoc. Euratom-ENEA-CREATE, Univ. Mediterranea RC, Loc. Feo di Vito I-89060, RC (Italy); Crisanti, F. [Associazione EURATOM-ENEA sulla Fusione, Frascati, C.P. 65, 00044-Frascati (Italy); De Tommasi, G. [Assoc. Euratom-ENEA-CREATE, University Napoli Federico II, Via Claudio 21, I-80125 Naples (Italy); Fresa, R. [DIFA, University della Basilicata, Contrada Macchia Romana I-85100, PZ (Italy); Sartori, F. [Euratom/UKAEA Fusion Assoc., Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Villone, F. [Assoc. Euratom-ENEA-CREATE, University Cassino, Via Di Biasio 43, I-03043 Cassino (Italy)

    2007-10-15

    The aim of this paper is to present some new tools used to review the capability of the ITER Poloidal Field (PF) system in controlling the broad range of plasma configurations presently forecasted during ITER operation. The attention is focused on the axi-symmetric aspects of plasma magnetic configuration control since they pose the greatest challenges in terms of control power and they have the largest impact on machine capital cost. Some preliminary results obtained during ongoing activities in collaboration between ENEA/CREATE and EFDA are presented. The paper is divided in two main parts devoted, respectively, to the presentation of a procedure for the PF current optimisation during the scenario, and of a software environment for the study of the PF system capabilities using the plasma linearized response. The proposed PF current optimisation procedure is then used to assess Scenario 2 design, also taking into account the presence of axisymmetric eddy currents and possible variations of poloidal beta and internal inductance. The numerical linear model based tool derived from the JET oriented eXtreme Shape Controller (XSC) tools is finally used to obtain results on the strike point sweeping in ITER.

  4. Preliminary design of the ITER ECH Upper Launcher

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, D., E-mail: dirk.strauss@kit.edu [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Aiello, G. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Chavan, R. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Cirant, S. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Baar, M. de [FOM, Van Vollenhovenlaan 659, 3527 JP, Utrecht (Netherlands); Farina, D. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Gantenbein, G. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Goodman, T.P. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Henderson, M.A. [ITER Organization, 13108 Saint-Paul-lez-Durance (France); Kasparek, W. [Institut für Plasmaforschung, IPF, D-70569 Stuttgart (Germany); Kleefeldt, K. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Landis, J.-D. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Meier, A. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Moro, A.; Platania, P. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Plaum, B. [Institut für Plasmaforschung, IPF, D-70569 Stuttgart (Germany); Poli, E. [Max-Planck-IPP, Euratom Association, D-85748 Garching (Germany); Ramponi, G. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Ronden, D. [FOM, Van Vollenhovenlaan 659, 3527 JP, Utrecht (Netherlands); Saibene, G. [Fusion for Energy, Barcelona (Spain); and others

    2013-11-15

    Highlights: • Front steering mirror design. • Plasma facing blanket shield module/first wall panel design. • Fixed frequency torus CVD diamond window serving as first tritium barrier. • Prototypes and tests of the above key components in the Launcher Handling and Testing Facility. -- Abstract: The design of the ITER electron cyclotron launchers recently reached the preliminary design level - the last major milestone before design finalization. The ITER ECH system contains 24 installed gyrotrons providing a maximum ECH injected power of 20 MW through transmission lines towards the tokamak. There are two EC launcher types both using a front steering mirror; one equatorial launcher (EL) for plasma heating and four upper launchers (UL) for plasma mode stabilization (neoclassical tearing modes and the sawtooth instability). A wide steering angle range of the ULs allows focusing of the beam on magnetic islands which are expected on the rational magnetic flux surfaces q = 1 (sawtooth instability), q = 3/2 and q = 2 (NTMs). In this paper the preliminary design of the ITER ECH UL is presented, including the optical system and the structural components. Highlights of the design include the torus CVD-diamond windows, the frictionless, front steering mechanism and the plasma facing blanket shield module (BSM). Numerical simulations as well as prototype tests are used to verify the design.

  5. Preliminary consideration of CFETR ITER-like case diagnostic system.

    Science.gov (United States)

    Li, G S; Yang, Y; Wang, Y M; Ming, T F; Han, X; Liu, S C; Wang, E H; Liu, Y K; Yang, W J; Li, G Q; Hu, Q S; Gao, X

    2016-11-01

    Chinese Fusion Engineering Test Reactor (CFETR) is a new superconducting tokamak device being designed in China, which aims at bridging the gap between ITER and DEMO, where DEMO is a tokamak demonstration fusion reactor. Two diagnostic cases, ITER-like case and towards DEMO case, have been considered for CFETR early and later operating phases, respectively. In this paper, some preliminary consideration of ITER-like case will be presented. Based on ITER diagnostic system, three versions of increased complexity and coverage of the ITER-like case diagnostic system have been developed with different goals and functions. Version A aims only machine protection and basic control. Both of version B and version C are mainly for machine protection, basic and advanced control, but version C has an increased level of redundancy necessary for improved measurements capability. The performance of these versions and needed R&D work are outlined.

  6. Magnetic analysis of the magnetic field reduction system of the ITER neutral beam injector

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Germán, E-mail: german.barrera@ciemat.es [CIEMAT, Laboratorio Nacional de Fusión, Avda. Complutense 22, 28040 Madrid (Spain); Ahedo, Begoña; Alonso, Javier; Ríos, Luis [CIEMAT, Laboratorio Nacional de Fusión, Avda. Complutense 22, 28040 Madrid (Spain); Chareyre, Julien; El-Ouazzani, Anass [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Agarici, Gilbert [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 07/08, 08019 Barcelona (Spain)

    2015-10-15

    The neutral beam system for ITER consists of two heating and current drive neutral beam injectors (HNB) and a diagnostic neutral beam (DNB) injector. The proposed physical plant layout allows a possible third HNB injector to be installed later. For the correct operation of the beam, the ion source and the ion path until it is neutralized must operate under a very low magnetic field environment. To prevent the stray ITER field from penetrating inside those mentioned critical areas, a magnetic field reduction system (MFRS) will envelop the beam vessels and the high voltage transmission lines to ion source. This system comprises the passive magnetic shield (PMS), a box like assembly of thick low carbon steel plates, and the Active Correction and Compensation Coils (ACCC), a set of coils carrying a current which depends on the tokamak stray field. This paper describes the magnetic model and analysis results presented at the PMS and ACCC preliminary design review held in ITER organization in April 2013. The paper focuses on the magnetic model description and on the description of the analysis results. The iterative process for obtaining optimized currents in the coils is presented. The set of coils currents chosen among the many possible solutions, the magnetic field results in the interest regions and the fulfillment of the magnetic field requirements are described.

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

    Energy Technology Data Exchange (ETDEWEB)

    Henning, C. (ed.)

    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.

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

    Science.gov (United States)

    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.

  9. Development of the superconductors for ITER magnet system

    Science.gov (United States)

    Shikov, A.; Nikulin, A.; Silaev, A.; Vorobieva, A.; Pantsyrnyi, V.; Vedernikov, G.; Salunin, N.; Sudiev, S.

    1998-10-01

    A review is given of the present status of the development and production of Nb 3Sn and Nb-Ti superconductors for the Model Coils and the real Magnet System of the International Thermonuclear Experimental Reactor (ITER) in the Russian Federation Home Team. It is shown that Nb 3Sn bronze processed superconductors produced for the Model Central Solenoid Coil insert meet the ITER joint Central Team requirements. In particular, the critical current density, measued in non-Cu area is not less than 550 A/mm 2 for 12 T at 4.2 K, the level of hysteresis losses is not in excess of 200 mJ/cm 3, and the Cu-stabilizing shell resistivity ratio of Cr-plated wire is 150. Internal tin Nb 3Sn superconductor development and test results are presented, confirming the possibility of their application for the ITER Magnet System winding. Nb-Ti superconductors for PF coils properties have also been considered. The possibility of Nb 3Sn and Nb-Ti superconductor manufacture with the use of large composite billets up to 300 mm in dia is shown, creating the possibility for large scale industrial production (several tens of tons/year) of these materials for the ITER Magnet System.

  10. Preliminary Design and Analysis of ITER In-Wall Shielding

    Institute of Scientific and Technical Information of China (English)

    LIU Changle; YU Jie; WU Songtao; CAI Yingxiang; PAN Wanjiang

    2007-01-01

    ITER in-wall shielding (IIS) is situated between the doubled shells of the ITER Vacuum Vessel (IVV). Its main functions are applied in shielding neutron, gamma-ray and toroidal field ripple reduction. The structure of IIS has been modelled according to the IVV design criteria which has been updated by the ITER team (IT). Static analysis and thermal expansion analysis were performed for the structure. Thermal-hydraulic analysis verified the heat removal capability and resulting temperature, pressure, and velocity changes in the coolant flow. Consequently, our design work is possibly suitable as a reference for IT's updated or final design in its next step.

  11. Electro-mechanical connection system for ITER in-vessel magnetic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Rizzolo, Andrea; Brombin, Matteo; Gonzalez, Winder [Consorzio RFX, Corso Stati Uniti, 4, 35127 Padova (Italy); Marconato, Nicolò, E-mail: nicolo.marconato@igi.cnr.it [Consorzio RFX, Corso Stati Uniti, 4, 35127 Padova (Italy); Peruzzo, Simone [Consorzio RFX, Corso Stati Uniti, 4, 35127 Padova (Italy); Arshad, Shakeib [Fusion for Energy, C/Josep Pla, 2, 08019 Barcelona (Spain); Ma, Yunxing; Vayakis, George [ITER Organization, Route de Vinon-sur-Verdon, 13067 St Paul Lez Durance (France); Williams, Adrian [Oxford Technologies Ltd, 7 Nuffield Way, Abingdon, Oxon, OX14 1RL (United Kingdom)

    2016-11-01

    Highlights: • Latest status of the ITER “Generic In-Vessel Magnetic Platform” design activity. • Integration within the ITER In-Vessel configuration model. • Geometry optimization based on thermo-mechanical and magnetic field 3D calculation. • Assessment of the remote handling maintenance compatibility. - Abstract: This paper presents the preliminary design of the “In-Vessel Magnetic platform”, which is a subsystem of the magnetic diagnostics formed by all the components necessary for guaranteeing the thermo-mechanical interface of the actual magnetic sensors with the vacuum vessel (VV), their protection and the electrical connection to the in-vessel wiring for the transmission of the detected signal with a minimum level of noise. The design has been developed in order to comply with different functional requirements: the mechanical attachment to the VV; the electrical connection to the in-vessel wiring; efficient heat transfer to the VV; the compatibility with Remote Handling (RH) system for replacement; the integration of metrology features for post-installation control; the Electro Magnetic Interference (EMI) shielding from Electron Cyclotron Heating (ECH) stray radiation without compromising the sensor pass band (15 kHz). Significant effort has been dedicated to develop the CAD model, integrated within the ITER In-Vessel configuration model, taking care of the geometrical compliance with the Blanket modules (modified in order to accommodate the magnetic sensors in suitable grooves) and the RH compatibility. Thorough thermo-mechanical and electro-magnetic Finite Element Method (FEM) analyses have been performed to assess the reliability of the system in standard and off-normal operating conditions for the low frequency magnetic sensors.

  12. Preliminary design and R&D of ITER diagnostic-radial X-ray camera

    Science.gov (United States)

    Hu, L.; Chen, K.; Chen, Y.; Cao, H.; Li, S.; Yu, H.; Zhan, J.; Shen, J.; Qin, S.; Sheng, X.; Zhao, J.; Niu, L.; Feng, C.; Ge, J.; Zhang, S.; Zhang, B.

    2017-10-01

    Preliminary design of ITER Radial X-ray Camera (RXC) has been finished. The structure design is optimized and installation process is studied considering the simplification and easiness of maintenance. Remote handling procedures are designed for the system maintenance after being activated. For detector cooling against high environment temperature which can be up to 240°, a dedicated gas cooling system using heat exchanger is designed. The structure analysis indicates that the stresses and displacements of most of the components under load combinations are within the allowable limits and no Safety Important Component (SIC) boundary is damaged. Through putting B4C material in the front part of DSM and around detectors for neutron shielding, the detectors are expected to survive the whole D-D phase. As for electronics, preliminary design of highly integrated pre-amplifier and program controllable mid-amplifier has been completed, both with bandwidth greater than 100 kHz to meet time resolution requirement of 20 kHz. To protect the electronics from intensive neutron and gamma irradiation, shielding cabinet capable of attenuating neutron flux down to 0.0001 and gamma dose 0.01 is designed. Besides, many R&D has been done to support the design. The tests of pre-amplifier and mid-amplifier indicated the electronics had no functional problem when debugging together and generally passed preliminary ElectroMagnetic Compatibility (EMC) test and nuclear test. The highly-integrated compact pre-amplifier has been used in EAST and proved useful. To test the feasibility of dedicated gas cooling system for detectors, a cooling test platform was built and preliminary cooling test has been done, indicating that during 250°baking the detector temperature is promising to be cooled down to the detector temperature limit of 75°. To increase signal to noise ratio, large area detector with dark current less than 2nA has been manufactured and worked steadily in EAST experiments.

  13. Preliminary RAMI analysis of DFLL TBS for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dagui [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230031 (China); Yuan, Run [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Wang, Jiaqun, E-mail: jiaqun.wang@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Wang, Fang; Wang, Jin [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China)

    2016-11-15

    Highlights: • We performed the functional analysis of the DFLL TBS. • We performed a failure mode analysis of the DFLL TBS. • We estimated the reliability and availability of the DFLL TBS. • The ITER RAMI approach was applied to the DFLL TBS for technical risk control in the design phase. - Abstract: ITER is the first fusion machine fully designed to prove the physics and technological basis for next fusion power plants. Among the main technical objectives of ITER is to test and validate design concepts of tritium breeding blankets relevant to the fusion power plants. To achieve this goal, China has proposed the dual functional lithium-lead test blanket module (DFLL TBM) concept design. The DFLL TBM and its associated ancillary system were called DFLL TBS. The DFLL TBS play a key role in next fusion reactor. In order to ensure reliable and available of DFLL TBS, the risk control project of DFLL TBS has been put on the schedule. As the stage of the ITER technical risk control policy, the RAMI (Reliability, Availability, Maintainability, Inspectability) approach was used to control the technical risk of ITER. In this paper, the RAMI approach was performed on the conceptual design of DFLL TBS. A functional breakdown was prepared on DFLL TBS, and the system was divided into 3 main functions and 72 basic functions. Based on the result of functional breakdown of DFLL TBS, the reliability block diagrams were prepared to estimate the reliability and availability of each function under the stipulated operating conditions. The inherent availability of the DFLL TBS expected after implementation of mitigation actions was calculated to be 98.57% over 2 years based on the ITER reliability database. A Failure Modes Effects and Criticality Analysis (FMECA) was performed with criticality charts highlighting the risk level of the different failure modes with regard to their probability of occurrence and their effects on the availability.

  14. Iterative reconstruction of magnetic induction using Lorentz transmission electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Phatak, C., E-mail: cd@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Gürsoy, D. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-03-15

    Intense ongoing research on complex nanomagnetic structures requires a fundamental understanding of the 3D magnetization and the stray fields around the nano-objects. 3D visualization of such fields offers the best way to achieve this. Lorentz transmission electron microscopy provides a suitable combination of high resolution and ability to quantitatively visualize the magnetization vectors using phase retrieval methods. In this paper, we present a formalism to represent the magnetic phase shift of electrons as a Radon transform of the magnetic induction of the sample. Using this formalism, we then present the application of common tomographic methods particularly the iterative methods, to reconstruct the 3D components of the vector field. We present an analysis of the effect of missing wedge and the limited angular sampling as well as reconstruction of complex 3D magnetization in a nanowire using simulations. - Highlights: • We present a formalism to represent electron-optical magnetic phase shift as a Radon transform of the 3D magnetic induction of the nano-object. • We have analyzed four different tomographic reconstruction methods for vectorial data reconstruction. • Reconstruction methods were tested for varying experimental limitations such as limited tilt range and limited angular sampling. • The analysis showed that Gridrec and SIRT methods performed better with lower errors than other reconstruction methods.

  15. Design features of internal tin superconductors for ITER magnetic system

    Energy Technology Data Exchange (ETDEWEB)

    Pantsyrnyi, V.I.; Shikov, A.K.; Nikulin, A.D.; Silaev, A.G.; Bel`akov, N.A.; Vdovin, V.F.; Semin, M.J. [Bochvar All-Russia Inst. of Inorganic Materials, Moscow (Russian Federation)

    1996-07-01

    The influence of parameters of internal tin superconductor design on the main working characteristics such as critical current density and hysteresis losses were analyzed. It was shown that having the value of hysteresis losses at the acceptable level of 400--600 mJ/cm{sup 3} the critical current density 20--30% higher than the value typical for bronze route processed superconductors was attainable in principle. The results of experimental work on the design of new types of internal tin superconductors for ITER magnetic system are given.

  16. Assembly and gap management strategy for the ITER NBI vessel passive magnetic shield

    Energy Technology Data Exchange (ETDEWEB)

    Ríos, Luis, E-mail: luis.rios@ciemat.es [CIEMAT Laboratorio Nacional de Fusión, Avda. Complutense 22, 28040 Madrid (Spain); Ahedo, Begoña; Alonso, Javier; Barrera, Germán; Cabrera, Santiago; Rincón, Esther; Ramos, Francisco [CIEMAT Laboratorio Nacional de Fusión, Avda. Complutense 22, 28040 Madrid (Spain); El-Ouazzani, Anass; Graceffa, Joseph; Urbani, Marc; Shah, Darshan [ITER Organization, Route de Vinon-sur-Verdon – CS 90 046, 13067 St Paul Lez Durance Cedex (France); Agarici, Gilbert [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3 – 07/08, 08019 Barcelona (Spain)

    2015-10-15

    The neutral beam system for ITER consists of two heating and current drive neutral ion beam injectors (HNB) and a diagnostic neutral beam (DNB) injector. The proposed physical plant layout allows a possible third HNB injector to be installed later. The HNB Passive Magnetic Shield (PMS) works in conjunction with the active compensation/correction coils to limit the magnetic field inside the Beam Line Vessel (BLV), Beam Source Vessel (BSV), High Voltage Bushing (HVB) and Transmission Line (TL) elbow to acceptable levels that do not interfere with the operation of the HNB components. This paper describes the current design of the PMS, having had only minor modifications since the preliminary design review (PDR) held in IO in April 2013, and the assembly strategy for the vessel PMS.

  17. Iter

    Science.gov (United States)

    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

  18. High magnetic field test of bismuth Hall sensors for ITER steady state magnetic diagnostic

    Science.gov (United States)

    Duran, I.; Entler, S.; Kohout, M.; Kočan, M.; Vayakis, G.

    2016-11-01

    Performance of bismuth Hall sensors developed for the ITER steady state magnetic diagnostic was investigated for high magnetic fields in the range ±7 T. Response of the sensors to the magnetic field was found to be nonlinear particularly within the range ±1 T. Significant contribution of the planar Hall effect to the sensors output voltage causing undesirable cross field sensitivity was identified. It was demonstrated that this effect can be minimized by the optimization of the sensor geometry and alignment with the magnetic field and by the application of "current-spinning technique."

  19. Plasma cleaning of ITER first mirrors in magnetic field

    CERN Document Server

    Moser, Lucas; Leipold, Frank; Reichle, Roger; Marot, Laurent; Meyer, Ernst

    2014-01-01

    To avoid reflectivity losses in ITER optical diagnostic systems, plasma sputtering of metallic First Mirrors is foreseen in order to remove deposits coming from the main wall (mainly beryllium and tungsten). Therefore plasma cleaning has to work on large mirrors (up to a size of 200*300 mm) and under the influence of strong magnetic fields (several Tesla). This work presents the results of plasma cleaning of aluminium and aluminium oxide (used as beryllium proxy) deposited on molybdenum mirrors. Using radio frequency (13.56 MHz) argon plasma, the removal of a 260 nm mixed aluminium/aluminium oxide film deposited by magnetron sputtering on a mirror (98 mm diameter) was demonstrated. 50 nm of pure aluminium oxide were removed from test mirrors (25 mm diameter) in a magnetic field of 0.35 T for various angles between the field lines and the mirrors surfaces. The cleaning efficiency was evaluated by performing reflectivity measurements, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy.

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

    Science.gov (United States)

    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.

  1. Controlled Nuclear Fusion by Magnetic Confinement and ITER

    CERN Document Server

    CERN. Geneva. Audiovisual Unit; Alvarez-Gaumé, Luís

    2005-01-01

    For may years harnessing fusion energy was considered the final solution to the world's energy crisis. ITER is the last step in the elusive quest. This presentation will provide in its various acientific, technological and political aspects.

  2. Preliminary failure modes and effects analysis on Korean HCCR TBS to be tested in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Mu-Young, E-mail: myahn74@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of); Jin, Hyung Gon; Lee, Dong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Yi-Hyun; Lee, Youngmin [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Highlights: • Postulated initiating events are identified through failure modes and effects analysis on the current HCCR TBS design. • A set of postulated initiating events are selected for consideration of deterministic analysis. • Accident evolutions on the selected postualted initiating events are qualitatively described for deterministic analysis. - Abstract: Korean Helium cooled ceramic reflector (HCCR) Test blanket system (TBS), which comprises Test blanket module (TBM) and ancillary systems in various locations of ITER building, is operated at high temperature and pressure with decay heat. Therefore, safety is utmost concern in design process and it is required to demonstrate that the HCCR TBS is designed to comply with the safety requirements and guidelines of ITER. Due to complexity of the system with many interfaces with ITER, a systematic approach is necessary for safety analysis. This paper presents preliminary failure modes and effects analysis (FMEA) study performed for the HCCR TBS. FMEA is a systematic methodology in which failure modes for components in the system and their consequences are studied from the bottom-up. Over eighty failure modes have been investigated on the HCCR TBS. The failure modes that have similar consequences are grouped as postulated initiating events (PIEs) and total seven reference accident scenarios are derived from FMEA study for deterministic accident analysis. Failure modes not covered here due to evolving design of the HCCR TBS and uncertainty in maintenance procedures will be studied further in near future.

  3. Influence of the magnetic field profile on ITER conductor testing

    NARCIS (Netherlands)

    Nijhuis, A.; Ilyin, Y.; Kate, ten H.H.J.

    2006-01-01

    We performed simulations with the numerical CUDI-CICC code on a typical short ITER (International Thermonuclear Experimental Reactor) conductor test sample of dual leg configuration, as usually tested in the SULTAN test facility, and made a comparison with the new EFDA-Dipole test facility offering

  4. Progress in the Integrated Simulation of Thermal-Hydraulic Operation of the ITER Magnet System

    CERN Document Server

    Bagnasco, M; Bessette, D; Marinucci, C

    2010-01-01

    A new integrated computer code is being developed for the simulations of the overall behavior of the ITER magnet cryo-system. The existing THEA, FLOWER and POWER codes, assembled as modules of a computational environment (Super-Magnet) have been upgraded to perform global simulations of the cooling circuit for the ITER magnet system. The thermal coupling resulting from the generic geometric configurations has been implemented to realize quasi-three-dimensional simulations of the winding pack. In this paper we present details on the model.

  5. Preliminary piping layout and integration of European test blanket modules subsystems in ITER CVCS area

    Energy Technology Data Exchange (ETDEWEB)

    Tarallo, Andrea, E-mail: andrea.tarallo@unina.it [CREATE, University of Naples Federico II, DII, P.le Tecchio, 80, 80125 Naples (Italy); Mozzillo, Rocco; Di Gironimo, Giuseppe [CREATE, University of Naples Federico II, DII, P.le Tecchio, 80, 80125 Naples (Italy); Aiello, Antonio; Utili, Marco [ENEA UTIS, C.R. Brasimone, Bacino del Brasimone, I-40032 Camugnano, BO (Italy); Ricapito, Italo [TBM& MD Project, Fusion for Energy, EU Commission, Carrer J. Pla, 2, Building B3, 08019 Barcelona (Spain)

    2015-04-15

    Highlights: • The use of human modeling tools for piping design in view of maintenance is discussed. • A possible preliminary layout for TBM subsystems in CVCS area has been designed with CATIA. • A DHM-based method to quickly check for maintainability of piping systems is suggested. - Abstract: This paper explores a possible integration of some ancillary systems of helium-cooled lithium lead (HCLL) and helium-cooled pebble-bed (HCPB) test blanket modules in ITER CVCS area. Computer-aided design and ergonomics simulation tools have been fundamental not only to define suitable routes for pipes, but also to quickly check for maintainability of equipment and in-line components. In particular, accessibility of equipment and systems has been investigated from the very first stages of the design using digital human models. In some cases, the digital simulations have resulted in changes in the initial space reservations.

  6. Analysis of the mechanical behaviour of the ITER magnet system

    Energy Technology Data Exchange (ETDEWEB)

    Jong, C.T.J.

    1996-03-01

    The International Thermonuclear Experimental Reactor (ITER) is a tokamak fusion device with the objective of demonstrating controlled ignition and an extended burn for a duration sufficient to achieve stationary conditions. The design of ITER will be based on extensive new design work supported by new physical and technological results. As part of the ITER Engineering Design Activities, the mechanical behaviour of the toroidal field coil (TF coil) system during normal operating conditions and fault conditions has to be analyzed. The displacements and/or stresses in the components must be limited to prevent mechanical failure of parts of the overall structure. These Engineering Design Activities are supported by R and D programs in the European Union. This final report describes the work carried out by ECN to develop a finite element model (FE model) of the TF-coil system which is suitable for the analysis of the mechanical behaviour and presents results obtained with this model. For the analysis of the mechanical behaviour, a large three dimensional (3D) non-linear finite element model has been developed. With this FE model a large number of load cases has been analyzed which correspond with several time points during multiple pulses. (orig./WL).

  7. Manufacture and test of seismic bellows for ITER magnet feeder

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chen, E-mail: liuchen@ipp.ac.cn [Institute of Plasma Physics Chinese Academy of Sciences, ShuShanhu Road No. 350, Hefei (China); Lu, Kun [Institute of Plasma Physics Chinese Academy of Sciences, ShuShanhu Road No. 350, Hefei (China); Sheng, Liang [AEROSUN-TOLA Expansion Joint Co., Ltd., Jiangjun Road No. 199, Nanjing (China); Song, Yuntao; Su, Jinjin [Institute of Plasma Physics Chinese Academy of Sciences, ShuShanhu Road No. 350, Hefei (China); Su, Man; Gung, Chenyu [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul-lez-Durance (France)

    2016-11-01

    Highlights: • The design of the double bellows was iterated with the results of analysis based on the Expansion Joint Manufacturers Association (EJMA) standard. • The seismic bellows was tested with cyclic pressurization of the interlayer space to 2 bars absolute pressure for 5 cycles. • 200 cycles of tensile fatigue test with 90 mm of stretching from the nominal design length. • A full tensile test with 315 mm of stretching from its nominal length was conducted. • The prototype bellows was qualified for its leak tightness (less than 1 × 10{sup −9} Pam{sup 3}/s of helium) at all time during the qualification test. - Abstract: This paper presents the key manufacturing and testing processes of the prototype ITER feeder seismic bellows. The design of the double bellows was iterated with the results of analysis based on the Expansion Joint Manufacturers Association (EJMA) standard. Each inner and outer bellows was supported in dedicated molds and formed by a hydraulic pressure machine rated at 800 tons. The double bellows were constructed by welding individual collars to the end flanges. The seismic bellows was tested with cyclic pressurization of the interlayer space to 2 bars absolute pressure for 5 cycles. This was followed by 200 cycles of tensile fatigue test with 90 mm of stretching from the nominal design length. After the mechanical fatigue test, a full tensile test with 315 mm of stretching from its nominal length was conducted. Helium leak tests, with the sensitivity of the helium leak detector set to 1 × 10{sup −9} Pa m{sup 3}/s of helium, were performed at different stages of pressure and mechanical tests. The prototype bellows was qualified for its leak tightness at all time during the qualification test.

  8. Mechanical property tests on structural materials for ITER magnet system at low temperatures in China

    Science.gov (United States)

    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.

  9. Review of design principles for ITER VV remote inspection in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Izard, Jean-Baptiste [CEA, LIST, Service de Robotique Interactive, 18 route du Panorama, BP6, Fontenay Aux Roses, F-92265 (France)], E-mail: jean-baptiste.izard@cea.fr; Perrot, Yann; Friconneau, Jean-Pierre [CEA, LIST, Service de Robotique Interactive, 18 route du Panorama, BP6, Fontenay Aux Roses, F-92265 (France)

    2009-06-15

    Because ITER magnet system has a limited number of mechanical and thermal stress cycles, shut down number of the toroidal field is limited during lifetime of ITER. Any inspection device able to withstand the toroidal field between two plasma shots will enhance the inspection frequency capacity of ITER during operation phase. In addition to the high magnetic field the system should also cope with high temperature, ultra-high vacuum and high radiation, in order to keep the reactor availability high. Radiation, ultra-high vacuum and temperature constraints already addressed by on going R and D activities within Europe-considering the required level of radiation is to date the highest encountered in remote handling, and that facing all these constraints at once is an additional issue to overcome. Whereas, operating remote handling systems in high magnetic field is quite new field of investigation. This paper aims to be a guideline for future designers to help them choose among options the adequate solution for an ITER relevant inspection device. It provides the designer an objective view of the different effects that stem from technical choices and help them deciding whether a technology is relevant or not depending on the task's requirements. We have selected a set of technologies and products available for structural design, actuation, sensing and data transmission in order to design inspection remote handling equipment for ITER in the given constraints. These different solutions are commented with specific considerations and directions to have them fit in the specifications. Different design strategies to cope with magnetic field are then discussed, which imply either insensitive design or using the magnetic field as a potential energy source and as a positioning help. This analysis is the first result of one of the projects in the PREFIT partnership, part of the European Fusion Training Scheme.

  10. Calculating the 3D magnetic field of ITER for European TBM studies

    CERN Document Server

    Äkäslompolo, Simppa; Bergmans, Thijs; Gagliardi, Mario; Galabert, Jose; Hirvijoki, Eero; Kurki-Suonio, Taina; Sipilä, Seppo; Snicker, Antti

    2015-01-01

    The magnetic perturbation due to the ferromagnetic test blanket modules (TBMs) may deteriorate fast ion confinement in ITER. This effect must be quantified by numerical studies in 3D. We have implemented a combined finite element method (FEM) -- Biot-Savart law integrator method (BSLIM) to calculate the ITER 3D magnetic field and vector potential in detail. Unavoidable geometry simplifications changed the mass of the TBMs and ferritic inserts (FIs) up to 26%. This has been compensated for by modifying the nonlinear ferromagnetic material properties accordingly. Despite the simplifications, the computation geometry and the calculated fields are highly detailed. The combination of careful FEM mesh design and using BSLIM enables the use of the fields unsmoothed for particle orbit-following simulations. The magnetic field was found to agree with earlier calculations and revealed finer details. The vector potential is intended to serve as input for plasma shielding calculations.

  11. Plasma cleaning of ITER First Mirrors in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Lucas, E-mail: lucas.moser@unibas.ch [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Steiner, Roland [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Leipold, Frank; Reichle, Roger [ITER Organization, Route de Vinon-sur-Verdon, 13115 St Paul-lez-Durance (France); Marot, Laurent; Meyer, Ernst [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

    2015-08-15

    To avoid reflectivity losses in ITER’s optical diagnostic systems, plasma sputtering of metallic First Mirrors is foreseen in order to remove deposits coming from the main wall (mainly beryllium and tungsten). Therefore plasma cleaning has to work on large mirrors (up to a size of 200 × 300 mm) and under the influence of strong magnetic fields (several Tesla). This work presents the results of plasma cleaning of aluminium and aluminium oxide (used as beryllium proxy) deposited on molybdenum mirrors. Using radio frequency (13.56 MHz) argon plasma, the removal of a 260 nm mixed aluminium/aluminium oxide film deposited by magnetron sputtering on a mirror (98 mm diameter) was demonstrated. 50 nm of pure aluminium oxide were removed from test mirrors (25 mm diameter) in a magnetic field of 0.35 T for various angles between the field lines and the mirrors surfaces. The cleaning efficiency was evaluated by performing reflectivity measurements, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy.

  12. The iterative solution of wave propagation in transverse magnetic mode for graded positive-negative

    Science.gov (United States)

    Nur Pratiwi, Beta; Suparmi, A.; Cari, C.; Arya Nugraha, Dewanta

    2017-01-01

    The iterative solution was used to obtain the electromagnetic wave propagation in transverse magnetic (TM) mode for a graded positive-negative refractive index. The graded graphs of negative permittivity and negative permeability were obtained in hyperbolic functions. By using hyperbolic function for permittivity and permeability in Maxwell equation and by separation variable, we obtained the electromagnetic differential equation. From the differential equation, we used the approachment using MacLaurin series to obtain the wave vector and magnetic fields equation. The distribution of the magnetic fields were given in graph visualization using Matlab software.

  13. Preliminary Analysis of Remote Handling Feasibility of the ITER Type B Radwaste Management System

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kwon Pyo; Oh, Wan Ho; Hong, Dae Seok; Ji, Young Yong; Kim, Tae Kook; Ahn, Sang Bok; Ryu, Wu Seog; Cheon, Je Keun; Na, Byung Chan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Jung, Ki Jung [National Fusion Research Institute, Daejeon (Korea, Republic of); John Blight [ITER Organization, Paul lez Durance (France)

    2010-10-15

    ITER Type B radwaste, which is defined as intermediate level and long lived radioactive waste, is mainly resulted from the replacement of in-vessel components of Tokamak such as divertor targets and domes and first walls of blankets, etc. They are mostly metallic components activated by neutrons and contaminated by tritium. The Type B radwaste is to be stored in ITER site for the life time of ITER. For this purpose the Type B radwaste treatment and storage system (RWTS) is located in the level 2 basement of the ITER Hot Cell Building (HCB)

  14. Magnetization study of ITER-type internal-Sn Nb3Sn superconducting wire

    Institute of Scientific and Technical Information of China (English)

    Zhang Chao-Wu; Zhou Lian; Andre Sulpice; Jean-Louis Soubeyroux; Christophe Verwaerde; Gia Ky Hoang; Zhang Ping-Xiang; Lu Ya-Feng; Tang Xian-De

    2007-01-01

    Through magnetization measurement with a SQUID magnetometer the heat treatment optimization of an international thermonuclear experimental reactor (ITER)-type internal-Sn Nb3Sn superconducting wire has been investigated. The irreversibility temperature T*(H), which is mainly dependent on A15 phase composition, was obtained by a warming and cooling cycle at a fixed field. The hysteresis width △M(H) which reflects the flux pinning situation of the A15 phase is determined by the sweeping of magnetic field at a constant temperature. The results obtained from differently heat-treated samples show that the combination of T*(H) with △M(H) measurement is very effective for optimizing the heat reaction process. The heat treatment condition of the ITER-type wire is optimized at 675 ℃/128 h, which results in a composition closer to stoichiometric Nb3Sn and a state with best flux pinning.

  15. Preliminary study of superconducting bulk magnets for Maglev

    Science.gov (United States)

    Fujimoto, Hiroyuki; Kamijo, Hiroki

    Recent development shows that melt-processed YBaCuO (Y123) or Rare Earth (RE)123 superconductors have a high Jc at 77 K and high magnetic field, leading to high field application as a superconducting quasi-permanent bulk magnet with the liquid nitrogen refrigeration. One of the promising applications is a superconducting magnet for the magnetically levitated (Maglev) train. We discuss a superconducting bulk magnet for the Maglev train in the aspect of a preliminary design of the bulk magnet and also processing for (L)REBaCuO bulk superconductors and their characteristic superconducting properties.

  16. Preliminary Results of Performance Measurements on a Cylindrical Hall-Effect Thruster with Magnetic Field Generated by Permanent Magnets

    Science.gov (United States)

    Polzin, K. A.; Raitses, Y.; Merino, E.; Fisch, N. J.

    2008-01-01

    The performance of a low-power cylindrical Hall thruster, which more readily lends itself to miniaturization and low-power operation than a conventional (annular) Hall thruster, was measured using a planar plasma probe and a thrust stand. The field in the cylindrical thruster was produced using permanent magnets, promising a power reduction over previous cylindrical thruster iterations that employed electromagnets to generate the required magnetic field topology. Two sets of ring-shaped permanent magnets are used, and two different field configurations can be produced by reorienting the poles of one magnet relative to the other. A plasma probe measuring ion flux in the plume is used to estimate the current utilization for the two magnetic configurations. The measurements indicate that electron transport is impeded much more effectively in one configuration, implying a higher thrust efficiency. Preliminary thruster performance measurements on this configuration were obtained over a power range of 100-250 W. The thrust levels over this power range were 3.5-6.5 mN, with anode efficiencies and specific impulses spanning 14-19% and 875- 1425 s, respectively. The magnetic field in the thruster was lower for the thrust measurements than the plasma probe measurements due to heating and weakening of the permanent magnets, reducing the maximum field strength from 2 kG to roughly 750-800 G. The discharge current levels observed during thrust stand testing were anomalously high compared to those levels measured in previous experiments with this thruster.

  17. Test of piezo-ceramic motor technology in ITER relevant high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Monti, Chiara, E-mail: chiara.monti@enea.it [Associazione EURATOM-ENEA sulla Fusione, via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Besi Vetrella, Ugo; Mugnaini, Giampiero; Neri, Carlo; Rossi, Paolo; Viola, Rosario [Associazione EURATOM-ENEA sulla Fusione, via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Dubus, Gregory; Damiani, Carlo [Fusion for Energy, c/ Josep Pla, 2 Torres Diagonal Litoral, 08019 Barcelona (Spain)

    2014-10-15

    In the framework of a Fusion for Energy (F4E) grant, a test campaign started in 2012 in order to assess the performance of the in-vessel viewing system (IVVS) probe concept and to verify its compatibility when exposed to ITER typical working conditions. ENEA laboratories went through with several tests simulating high magnetic fields, high temperature, high vacuum, gamma radiation and neutron radiation. A customized motor has been adopted to study the performances of ultrasonic piezo motors technology in high magnetic field conditions. This paper reports on the testing activity performed on the motor in a multi Tesla magnetic field. The job was carried out in a test facility of ENEA laboratories able to achieve 14 T. A maximum field of 10 T, fully compliant with ITER requirements (8 T), was applied. A specific mechanical assembly has been designed and manufactured to hold the motor in the region with high homogeneity of the field. Results obtained so far indicate that the motor is compatible with high magnetic fields, and are presented in the paper.

  18. Room Temperature Magnetic Determination of the Current Center Line for the ITER TF Coils

    CERN Document Server

    Lerch, Philippe; Buzio, Marco; Negrazus, Marco; Baynham, Elwyn; Sanfilippo, Stephane; Foussat, Arnaud

    2014-01-01

    The ITER tokamak includes 18 superconducting D-shaped toroidal field (IT) coils. Unavoidable shape deformations as well as assembly errors will lead to field errors, which can be modeled with the knowledge of the current center line (CCL). Accurate survey during the entire manufacturing and assembly process, including transfer of survey points, is complex. In order to increase the level of confidence, a room temperature magnetic measurement of the CCL on assembled and closed winding packs is foreseen, prior to insertion into their cold case. In this contribution, we discuss the principle of the CCL determination and present a low frequency ac measurement system under development at PSI, within an ITER framework contract. The largest current allowed to flow in the TF coil at room temperature and the precision requirements for the determination of the CCL loci of the coil are hard boundaries. Eddy currents in the radial plates, the winding pack enclosures, and possibly from iron in the reinforced concrete floor...

  19. Conceptual architecture of the plant system controller for the magnetics diagnostic of the ITER tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Neto, A.C., E-mail: Andre.Neto@f4e.europa.eu [Fusion for Energy, 08019 Barcelona (Spain); Arshad, S.; Sartori, F. [Fusion for Energy, 08019 Barcelona (Spain); Vayakis, G. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance (France); Ambrosino, G. [Consorzio CREATE/Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Batista, A. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Bas, I. [GTD Sistemas de Información, 08005 Barcelona (Spain); Campagnolo, R. [Fusion for Energy, 08019 Barcelona (Spain); Carvalho, B.B. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); De Magneval, G. [GTD Sistemas de Información, 08005 Barcelona (Spain); De Tommasi, G. [Consorzio CREATE/Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Dominguez, O. [GTD Sistemas de Información, 08005 Barcelona (Spain); Fernandez-Hernando, J.L. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance (France); Pironti, A. [Consorzio CREATE/Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Simrock, S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance (France); and others

    2015-10-15

    In a tokamak the magnetic diagnostics are key to the exploitation of the machine. They play a central role in the real-time control of fundamental plasma properties, such as the plasma shape and position, while also contributing with important data to a better understanding of the plasma physics. One of the particular challenges of the ITER magnetics diagnostic is the need to balance high system reliability with sufficient freedom to tune and improve the quality of the diagnostic physics output. This requirement calls for a design pattern where the functions related to plasma control and protection are loosely coupled with the functions related to the plasma science. This work reports on the current status of the magnetics plant system controller design and discusses some possible design solutions that address the aforementioned issue.

  20. A Preliminary Analysis of Dose Rates Associated with ITER CVCS Equipment/Area Location

    Energy Technology Data Exchange (ETDEWEB)

    Blakeman, Edward D [ORNL; Ilas, Dan [ORNL; Petrov, Andrei Y [ORNL

    2012-03-01

    A preliminary analysis of the ITER Chemical and Volume Control System (CVCS) Area was performed to assess dose rates outside the walls and ceiling of the facility after 1.5 years of operation at shutdown, 2 days, and 10 days after shutdown. For this purpose a simplified Monte Carlo computer model was developed using the MCNP (MCNP5 Ver. 1.51) code. Two components are included: the smaller filter tank and the larger ion exchanger. These pieces of equipment are associated with the Integrated Blanket ELM Divertor Primary Heat Transfer System, which will have the largest dose rates associated with activated corrosion products during operation in comparison with other systems. The ion exchanger contained two source regions, a 1.2-m-thick resin bed above a 0.55 m-thick skirt, and a 0.8-m-thick water region. The filter constituted an additional source. Thus the model consisted of three sources (filter, resin, water), homogeneously distributed within the appropriate source regions. However, much of the results (that address individual isotopes) are presented with the two sources in the ion exchanger combined. In these cases the sources are referred to as the 'ion exchanger source' and the 'filter source.' Dimensions for the facility and components, as well as source isotopes and strengths, and material densities, were supplied by US ITER. Because of its simplification, the model does not contain pipes. Consequently, radiation streaming through pipe penetrations, radiation emanating from the pipes, and shielding from the pipes were not considered in this analysis. Dose rates on the outside of two walls and the ceiling were calculated. The two walls are labeled as the 'long' wall (aligned with the X-axis) and the 'short' wall (aligned with the Y-axis). These walls and ceiling were nominally set to 30-cm-thick concrete. In the original analysis, standard concrete (2.3 g/cc density) was used. In addition to the shielding walls/ceiling, a

  1. Performance assessment methodology as applied to the Greater Confinement Disposal site: Preliminary results of the third performance iteration

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.J. [Sandia National Labs., Albuquerque, NM (United States); Baer, T.A. [GRAM Inc., Albuquerque, NM (United States)

    1994-12-31

    The US Department of Energy has contracted Sandia National Laboratories to conduct a performance assessment of the Greater Confinement Disposal facility, Nevada. The performance assessment is an iterative process in which transport models are used to prioritize site characterization data collection. Then the data are used to refine the conceptual and performance assessment models. The results of the first two performance assessment iterations indicate that the site is likely to comply with the performance standards under the existing hydrologic conditions. The third performance iteration expands the conceptual model of the existing transport system to include possible future events and incorporates these processes in the performance assessment models. The processes included in the third performance assessment are climate change, bioturbation, plant uptake, erosion, upward advection, human intrusion and subsidence. The work completed to date incorporates the effects of bioturbation, erosion and subsidence in the performance assessment model. Preliminary analyses indicate that the development of relatively deep-rooting plant species at the site, which could occur due to climate change, irrigated farming or subsidence, poses the greatest threat to the site`s performance.

  2. Cryogenic Properties of Inorganic Insulation Materials for ITER Magnets: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Simon, N.J.

    1994-12-01

    Results of a literature search on the cryogenic properties of candidate inorganic insulators for the ITER TF magnets are reported. The materials investigated include: Al{sub 2}O{sub 3}, AlN, MgO, porcelain, SiO{sub 2}, MgAl{sub 2}O{sub 4}, ZrO{sub 2}, and mica. A graphical presentation is given of mechanical, elastic, electrical, and thermal properties between 4 and 300 K. A companion report reviews the low temperature irradiation resistance of these materials.

  3. Thermo-mechanical analyses of ITER in-vessel magnetic sensor assembly

    Science.gov (United States)

    Gonzalez, W.; Arshad, S.; Peruzzo, S.; Portales, M.; Rizzolo, A.; Vayakis, G.

    2014-08-01

    This paper summarizes the work concerning design studies of the ITER in-vessel discrete magnetic sensor assemblies, with particular emphasis on the thermal behaviour of the Low Temperature Co-fired Ceramic (LTCC) magnetic sensor and on the thermo-mechanical aspects of the interface with the Vacuum Vessel (VV). The paper summarises the results of FEM thermal analyses performed on the LTCC sensor head and on the sensor assembly to assess the temperature distribution during operating conditions, which could affect the sensor signal due to Temperature-Induced Electromotive Force effect. The paper then concentrates on mechanical analysis of the Base-Plate to assess that the stress and deformation due to the welding to the VV are acceptable to guarantee a sound installation and a suitable thermal contact of the sensor assembly to the VV.

  4. Preliminary Thermal Mechanical Analysis of the Equatorial Thermal Shield for ITER

    Institute of Scientific and Technical Information of China (English)

    雷明准; 宋云涛; 杜世俊; 叶民友; 奚维斌; 刘旭峰

    2012-01-01

    Thermal analysis of the equatorial thermal shield for ITER is conducted in order to confirm that the cooling tube design was reasonable under both the plasma operational and the baking operational conditions. The structural performance was analyzed by means of the finite element software ANSYS. A comparison of the results with design requirements shows that the results of the simulation are within allowable design requirements, which indicates the feasibility and reliability of the equatorial thermal shield structure.

  5. Preliminary Neutronics Analysis of the ITER Toroidal Interferometer and Polarimeter Diagnostic Corner Cube Retroreflectors

    Energy Technology Data Exchange (ETDEWEB)

    Tresemer, K. R.

    2015-07-01

    ITER is an international project under construction in France that will demonstrate nuclear fusion at a power plant-relevant scale. The Toroidal Interferometer and Polarimeter (TIP) Diagnostic will be used to measure the plasma electron line density along 5 laser-beam chords. This line-averaged density measurement will be input to the ITER feedback-control system. The TIP is considered the primary diagnostic for these measurements, which are needed for basic ITER machine control. Therefore, system reliability & accuracy is a critical element in TIP’s design. There are two major challenges to the reliability of the TIP system. First is the survivability and performance of in-vessel optics and second is maintaining optical alignment over long optical paths and large vessel movements. Both of these issues greatly depend on minimizing the overall distortion due to neutron & gamma heating of the Corner Cube Retroreflectors (CCRs). These are small optical mirrors embedded in five first wall locations around the vacuum vessel, corresponding to certain plasma tangency radii. During the development of the design and location of these CCRs, several iterations of neutronics analyses were performed to determine and minimize the total distortion due to nuclear heating of the CCRs. The CCR corresponding to TIP Channel 2 was chosen for analysis as a good middle-road case, being an average distance from the plasma (of the five channels) and having moderate neutron shielding from its blanket shield housing. Results show that Channel 2 meets the requirements of the TIP Diagnostic, but barely. These results suggest other CCRs might be at risk of exceeding thermal deformation due to nuclear heating.

  6. Preliminary analysis of patent trends for magnetic fusion technology

    Energy Technology Data Exchange (ETDEWEB)

    Levine, L.O.; Ashton, W.B.; Campbell, R.S.

    1984-02-01

    This study presents a preliminary analysis of development trends in magnetic fusion technology based on data from US patents. The research is limited to identification and description of general patent activity and ownership characteristics for 373 patents. The results suggest that more detailed studies of fusion patents could provide useful R and D planning information.

  7. Embeddings of Iteration Trees

    OpenAIRE

    Mitchell, William

    1992-01-01

    This paper, dating from May 1991, contains preliminary (and unpublishable) notes on investigations about iteration trees. They will be of interest only to the specialist. In the first two sections I define notions of support and embeddings for tree iterations, proving for example that every tree iteration is a direct limit of finite tree iterations. This is a generalization to models with extenders of basic ideas of iterated ultrapowers using only ultrapowers. In the final section (which is m...

  8. Protecting ITER walls: fast ion power loads in 3D magnetic field

    Science.gov (United States)

    Kurki-Suonio, T.; Särkimäki, K.; Äkäslompolo, S.; Varje, J.; Liu, Y.; Sipilä, S.; Asunta, O.; Hirvijoki, E.; Snicker, A.; Terävä, J.; Cavinato, M.; Gagliardi, M.; Parail, V.; Saibene, G.

    2017-01-01

    The fusion alpha and beam ion with steady-state power loads in all four main operating scenarios of ITER have been evaluated by the ASCOT code. For this purpose, high-fidelity magnetic backgrounds were reconstructed, taking into account even the internal structure of the ferritic inserts and tritium breeding modules (TBM). The beam ions were found to be almost perfectly confined in all scenarios, and only the so-called hybrid scenario featured alpha loads reaching 0.5 MW due to its more triangular plasma. The TBMs were not found to jeopardize the alpha confinement, nor cause any hot spots. Including plasma response did not bring dramatic changes to the load. The ELM control coils (ECC) were simulated in the baseline scenario and found to seriously deteriorate even the beam confinement. However, the edge perturbation in this case is so large that the sources have to be re-evaluated with plasma profiles that take into account the ECC perturbation.

  9. R and D of the key components for ITER magnet supports

    Energy Technology Data Exchange (ETDEWEB)

    Lee, P.Y., E-mail: lipy@swip.ac.cn [Department of Material and Fusion Engineering, Southwestern Institute of Physics (SWIP), P.O. Box 432, Chengdu 610041 (China); Hou, B.L.; Pan, C.J. [Department of Material and Fusion Engineering, Southwestern Institute of Physics (SWIP), P.O. Box 432, Chengdu 610041 (China); Cheng, Z.Q.; Huai, K.W. [Stainless Steel Institute, Baoshan Iron and Steel Co., Ltd, 580 Changjiang Road, Baoshan District, Shanghai 200431 (China); Savary, F.; Fu, Y.K.; Gallix, R. [Tokamak Department, ITER Organization, Cadarache, 13108 St. Paul-Lez-Durance (France)

    2010-12-15

    In this article, we report the recent progress of the R and D work for ITER magnet supports, including 316LN raw material development, designing and manufacturing, development of gravity supports (GS) and poloidal field (PF) supports. 316LN stainless steel has been developed successfully with nitrogen content up to 0.188 mass%. These materials show very good mechanical properties at both room temperature and low temperature. The GS conceptual design using welded connections is replaced with pre-stressed bolted connections in order to reduce the risk of defects and manufacturing cost. The finite element model (FEM) analysis for this design shows that neither terrible stress concentrations nor large deformations would occur during either normal or abnormal operation. Attaching the thermal anchor to the flexible plate is made possible by a brazing connection and is carried out in the GS manufacturing. For PF supports, the wear resistance of the strut dowel of PF3-4 support improved after ion implantation.

  10. Manufacture and test of prototype water pipe chase barrier in ITER Magnet Feeder system

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Kun, E-mail: lukun@ipp.ac.cn [Institute of Plasma Physics, Shushan Hu Road 350, Hefei, Anhui (China); Wen, Xinjie; Liu, Chen; Song, Yuntao [Institute of Plasma Physics, Shushan Hu Road 350, Hefei, Anhui (China); Niu, Erwu [ITER China, 15B Fuxing Road, Beijing 100862 (China); Gung, Chenyu; Su, Man [ITER Organization, Route de Vinon-sur-Verdon – CS 90046, 13067 St Paul-lez-Durance Cedex (France)

    2016-11-01

    The Magnet Feeder system in the International Thermonuclear Experimental Reactor (ITER) deploys electrical currents and supercritical helium to the superconducting magnets and the magnet diagnostic signals to the operators. In the current design, the feeders located in the upper L3 level of the Tokamak gallery penetrate the Tokamak coolant water system vault, the biological shield and the cryostat. As a secondary confinement to contain the activated coolant water in the vault in the case of water pipe burst accident, a water barrier is welded between the penetration in the water pipe chase outer wall and the mid-plane of the vacuum jacket of the Feeder Coil Terminal Box (CTB). A thin-wall stainless steel diaphragm with an omega shape profile is welded around the CTB as the water barrier to endure 2 bar hydraulic pressure. In addition, the barrier is designed as a flexible compensator to withstand a maximum of 15 mm of axial displacement of the CTB in case of helium leak accident without failure. This paper presents the detail configuration, the manufacturing and assembly processes of the water barrier. Test results of the prototype water barrier under simulated accident conditions are also reported. Successful qualification of the design and manufacturing process of the water barrier lays a good foundation for the series production of this subsystem.

  11. ELM Suppression in DIII-D ITER-like Plasmas Using n = 2 Magnetic Perturbations

    Science.gov (United States)

    Nazikian, R.; Grierson, B. A.; Okabayashi, M.; Tobias, B. J.; Eldon, D.; Evans, T. E.; Ferraro, N. M.; Groebner, R. J.; Paz-Soldan, C.; Strait, E. J.; Haskey, S. R.; King, J. D.; McKee, G. R.; Moyer, R. A.; Orlov, D. M.; Shafer, M. W.

    2014-10-01

    A robust window of edge localized mode (ELM) suppression was observed at elevated magnetic safety factor (q95 ~ 4.1) in ITER-like plasmas with even parity n = 2 resonant magnetic perturbation (RMP) using the internal I-coils. Variation of the upper and lower I-coil phasing was used to explore the importance of pitch alignment vs kink alignment for ELM suppression. Both the pedestal density and ELM suppression were strongly dependent on I-coil phasing and a large variation in the plasma response amplitude was measured on multiple diagnostics. Surprisingly, toroidal rotation of the even parity n = 2 RMP led to the loss of ELM suppression, indicating that components of the residual error field orthogonal to the kink mode may be important near the threshold for ELM suppression. Work supported by the US Department of Energy under DE-AC02-09CH11466, DE-FC02-04ER54698, DE-AC05-06OR23100, DE-FG02-89ER53296, DE-FG02-08ER54999, DE-FG02-07ER54917, and DE-AC05-00OR22725.

  12. Analysis of active and passive magnetic field reduction systems (MFRS) of the ITER NBI

    Energy Technology Data Exchange (ETDEWEB)

    Roccella, M. [L.T. Calcoli S.a.S., Piazza Prinetti 26/B, Merate (Lecco) (Italy)], E-mail: roccella@ltcalcoli.it; Lucca, F.; Roccella, R. [L.T. Calcoli S.a.S., Piazza Prinetti 26/B, Merate (Lecco) (Italy); Pizzuto, A.; Ramogida, G. [Associazione EURATOM sulla Fusione - ENEA Frascati (Italy); Portone, A.; Tanga, A. [ITER EFDA (Italy); Formisano, A.; Martone, R. [CREATE Napoli (Italy)

    2007-10-15

    In ITER two heating (HNBI) and one diagnostic neutral beam injectors (DNBI) are foreseen. Inside these components there are very stringent limits on the magnetic field (the flux density must be below some G along the ion path and below 20 G in the neutralizing regions). To achieve these performances in an environment with high stray field due to the plasma and the poloidal field coils (PFC), both passive and active shielding systems have been foreseen. The present design of the magnetic field reduction systems (MFRS) is made of seven active coils and of a box surrounding the NBI region, consisting of ferromagnetic plates. The electromagnetic analyses of the effectiveness of these shields have been performed by a 3D FEM model using ANSYS code for the HNBI. The ANSYS models of the ferromagnetic box and of the active coils are fully parametric, thus any size change of the ferromagnetic box and coils (linear dimension or thickness) preserving the overall box shape could be easily reproduced by simply changing some parameter in the model.

  13. Progressive Magnetic Resonance Image Reconstruction Based on Iterative Solution of a Sparse Linear System

    Science.gov (United States)

    Fahmy, Ahmed S.; Gabr, Refaat E.; Heberlein, Keith; Hu, Xiaoping P.

    2006-01-01

    Image reconstruction from nonuniformly sampled spatial frequency domain data is an important problem that arises in computed imaging. Current reconstruction techniques suffer from limitations in their model and implementation. In this paper, we present a new reconstruction method that is based on solving a system of linear equations using an efficient iterative approach. Image pixel intensities are related to the measured frequency domain data through a set of linear equations. Although the system matrix is too dense and large to solve by direct inversion in practice, a simple orthogonal transformation to the rows of this matrix is applied to convert the matrix into a sparse one up to a certain chosen level of energy preservation. The transformed system is subsequently solved using the conjugate gradient method. This method is applied to reconstruct images of a numerical phantom as well as magnetic resonance images from experimental spiral imaging data. The results support the theory and demonstrate that the computational load of this method is similar to that of standard gridding, illustrating its practical utility. PMID:23165034

  14. Iterative cross-correlation analysis of resting state functional magnetic resonance imaging data.

    Directory of Open Access Journals (Sweden)

    Liqin Yang

    Full Text Available Seed-based cross-correlation analysis (sCCA and independent component analysis have been widely employed to extract functional networks from the resting state functional magnetic resonance imaging data. However, the results of sCCA, in terms of both connectivity strength and network topology, can be sensitive to seed selection variations. ICA avoids the potential problems due to seed selection, but choosing which component(s to represent the network of interest could be subjective and problematic. In this study, we proposed a seed-based iterative cross-correlation analysis (siCCA method for resting state brain network analysis. The method was applied to extract default mode network (DMN and stable task control network (STCN in two independent datasets acquired from normal adults. Compared with the networks obtained by traditional sCCA and ICA, the resting state networks produced by siCCA were found to be highly stable and independent on seed selection. siCCA was used to analyze DMN in first-episode major depressive disorder (MDD patients. It was found that, in the MDD patients, the volume of DMN negatively correlated with the patients' social disability screening schedule scores.

  15. Magnetization and Inter-Filament Contact in HEP and ITER Bronze-Route Nb3Sn Wires

    CERN Document Server

    Bordini, B; Bottura, L; Devred, A; Jewell, M; Richter, D; Senatore, C

    2011-01-01

    Magnetization measurements are relevant tests for the characterization of superconductors. Practically they are the only measurements that allow estimating the critical current density at low fields of low temperature superconductors, the effective filament size and the hysteresis losses. For this purpose CERN, in collaboration with the University of Geneva, has carried out magnetization measurements on five types of Nb3Sn wires: three bronze route strands used in the ITER project; one Powder In Tube (PIT) and one Internal Tin (IT) wires used for developing next generation accelerator magnets. The field dependent magnetization has been determined using three set-ups: a Vibrating Sample Magnetometer (VSM), a Superconducting Quantum Interference Device (SQUID) and a special system used for the production control of LHC strands. Samples of different lengths have been tested to check the different coupling between the filaments. Unexpectedly, it was found that the magnetization of the tested bronze wires was stro...

  16. Magnetization and Inter-Filament Contact in HEP and ITER Bronze-Route Nb(3)Sn Wires

    CERN Document Server

    Bordini, B; Devred, A; Richter, D; Bessette, D; Jewell, M; Bottura, L

    2011-01-01

    Magnetization measurements are relevant tests for the characterization of superconductors. Practically they are the only measurements that allow estimating the critical current density at low fields of low temperature superconductors, the effective filament size and the hysteresis losses. For this purpose CERN, in collaboration with the University of Geneva, has carried out magnetization measurements on five types of Nb(3)Sn wires: three bronze route strands used in the ITER project; one Powder In Tube (PIT) and one Internal Tin (IT) wires used for developing next generation accelerator magnets. The field dependent magnetization has been determined using three setups: a Vibrating Sample Magnetometer (VSM), a Superconducting Quantum Interference Device (SQUID) and a special system used for the production control of LHC strands. Samples of different lengths have been tested to check the different coupling between the filaments. Unexpectedly, it was found that the magnetization of the tested bronze wires was str...

  17. A preliminary design and structural analysis of the lifting tools for 40° sector sub-assembly and handling ITER components

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Kyoungo, E-mail: namko@nfri.re.kr [ITER Korea, Gwahangno 113, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Park, Hyunki; Im, Kihak; Kim, Dongjin; Ahn, Heejae [ITER Korea, Gwahangno 113, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Lee, Jaehyuk; Moon, Jaewhan [SFA Inc., 166 Sinhang-ri, Dunpo-myeon, Asan-si, Chungcheongnam-do 336-873 (Korea, Republic of); Watson, Emma; Shaw, Robert [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    The purpose-built, ITER tokamak assembly tools, which are to be provided by Korea, should be designed to meet: the assembly plan, space reservations, safety standards, simple operations, efficient maintenance, and so on. It is very important that the ITER assembly tools are able to lift and transfer ITER components or their sub-assemblies to their assembled position safely. Furthermore, the lifting tools will lift and handle very heavy loads that can be more than 1200 tonnes sometimes. Therefore, the ITER lifting tools must be designed to endure these heavy load conditions with regard to their structural integrity. Also, these designs should be verified through an appropriate method. The preliminary design of the sector lifting tool and associated lifting attachments are introduced in this paper. The sector lifting tool was designed especially to lift and handle various ITER components by adjusting the lifting centre. The structural analysis results using ANSYS are described considering the heaviest load condition. The results of the analysis show that; all stresses applied on the lifting tool are lower than the allowable stress of the applied material.

  18. A preliminary magnetic study of Sawa lake sediments, Southern Iraq

    Science.gov (United States)

    Ameen, Nawrass

    2016-04-01

    A preliminary magnetic study combined with chemical analyses was carried out in Sawa Lake in Al-Muthanna province, southern Iraq, about 22 km south west of Samawa city (31°18'48.80"N, 45°0'25.25"E). The lake is about 4.74 km length, 1.75 km width and 5.5 m height, it is surrounded by a salt rim which is higher than the lake water by about 2.8 m and sea water by about 18.5 m (Naqash et al., 1977 in Hassan, 2007). The lake is an elongated closed basin with no surface water available to it, it may be fed by groundwater of the Euphrates and Dammam aquifers through system of joints and cracks. This study aims to investigate the concentrations of selected heavy metals as pollutants and magnetic susceptibility (MS) and other magnetic properties of sediment samples from fifty sites collected from the bottom of the lake, the study area lies in an industrial area. The results show spatial variations of MS with mean value of about 4.58 x 10-8 m3 kg-1. Scanning electron microscopy and magnetic mineralogy parameters indicate the dominance of soft magnetic phase like magnetite and presence of hard magnetic phase like hematite. Spatial variations of MS combined with the concentrations of heavy metals suggests the efficiency of magnetic methods as effective, inexpensive and non-time consuming method to outlining the heavy metal pollution. References: Hassan W.F., 2007. The Physio-chemical characteristic of Sawa lake water in Samawa city-Iraq. Marine Mesopotamica, 22(2), 167-179.

  19. The ITER 3D Magnetic Diagnostic Response to Applied n=3 and n=4 RMP's

    Energy Technology Data Exchange (ETDEWEB)

    Lazerson, S A [PPPL

    2014-09-01

    The ITER magnetic diagnostic response to applied n=3 and n=4 RMPs has been calculated for the 15MA scenario. The VMEC code was utilized to calculate free boundary 3D ideal MHD equilibria, where the non-stellarator symmetric terms were included in the calculation. This allows an assessment to be made of the possible boundary displacements due to RMP application in ITER. As the VMEC code assumes a continuous set of nested flux surface, the possibility of island and stochastic region formation is ignored. At the start of the current at-top (L-Mode) application of n = 4 RMP's indicates approximately 1 cm peak-to-peak displacements on the low field side of the plasma while later in the shot (H-mode) perturbations as large as 3 cm are present. Forward modeling of the ITER magnetic diagnostics indicates significant non-axisymmetric plasma response, exceeding 10% the axisymmetric signal in many of the flux loops. Magnetic field probes seem to indicate a greater robustness to 3D effects but still indicate large sensitivities to 3D effects in a number of sensors. Forward modeling of the diagnostics response to 3D equilibria allows assessment of diagnostics design and control scenarios.

  20. Effect of a TBM on the Toroidal Magnetic Field Ripple in the ITER and Measures to Reduce the Ripple

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Young Dug; Lee, Dong Won; Kim, Suk Kwon; Hong, Bong Guen

    2008-11-15

    The ITER (International Thermonuclear Experimental Reactor) tokamak has 18 toroidal magnetic field (TF) coils, and the discreteness of these TF coils causes toroidally non-axisymmetric perturbations of the magnetic field. It is called a TF ripple and could lead to losses of high-energy particles, and an unfavorable heat load on the plasma facing components. In the ITER design, a ferromagnetic insert (FI) is employed to reduce the TF ripple, and an optimization of the FI design is ongoing. Also, since test blanket modules (TBMs) will be installed in the ITER, which are made of a ferromagnetic material, they also affect the TF ripple. We assessed the effects of the thickness of the FIs on the TF ripple in order to optimize the FI. And we analyzed how the TBMs distort the TF, and calculated the TF ripple for various amounts of a ferromagnetic material and the positions of the TBMs. A simple correction coil was adopted in order to reduce the TBM induced TF ripple to the required value of 0.3 %. We proposed technically available measures to reduce the TF ripple to the required value.

  1. Advances in the Understanding of ELM Suppression by Resonant Magnetic Perturbations (RMPs) in DIII-D and Implications for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Nazikian, R. [PPPL

    2014-09-01

    Experiments on DIII-D have expanding the operating window for RMP ELM suppression to higher q95 with dominant electron heating and fully non-inductive current drive relevant to advanced modes of ITER operation. Robust ELM suppression has also been obtained with a reduced coil set, mitigating the risk of coil failure in maintaining ELM suppression in ITER. These results significantly expand the operating space and reduce risk for obtaining RMP ELM suppression in ITER. Efforts have also been made to search for 3D cause of ELM suppression. No internal non-axisymmetric structure is detected at the top of the pedestal, indicating that the dominant effect of the RMP is to produce an n=0 transport modification of the profiles. Linear two fluid MHD simulations using M3D-C1 indicate resonant field penetration and significant magnetic stochasticity at the top of the pedestal, consistent with the absence of detectable 3D structure in that region. A profile database was developed to compare the scaling of the pedestal and global confinement with the applied 3D field strength in ELM suppressed and ELM mitigated plasmas. The EPED pedestal model accurately predicts the measured pedestal pressure at the threshold of ELM suppression, increasing confidence in theoretical projections to ITER pedestal conditions. Both the H-factor (H(sub)98y2) and thermal energy confinement time do not degrade substantially with applied RMP fields near the threshold of ELM suppression, enhancing confidence in the compatibility of ITER high performance operation with RMP ELM suppression.

  2. Magnetic Measurement of the Current Center Line of the Toroidal Field Coil of ITER at Room Temperature

    CERN Document Server

    Deniau, L; Buzio, M; Knaster, J; Savary, F

    2012-01-01

    Geometrical deformations and assembly errors in the ITER Toroidal Field (TF) coils will lead to magnetic field perturbations, which could degrade plasma confinement and eventually lead to disruption. Extensive computational studies of the influence of coil deformations and assembly errors on plasma behavior have given the basis for definition of the geometric tolerance of the Current Centre Line (CCL) of the winding pack of the TF coil. This paper describes an analysis method to establish the feasibility to measure the magnetic CCL locus of the final winding pack (WP) with accuracy better than 1 mm. The proposed method is based on arrays of gradient coils accurately mounted with respect to the WP fiducial marks and datum surfaces. The magnetic measurements will be performed at defined locations around the WP perimeter to characterize accurately the CCL locus. The analysis emphases the robustness and sensitivity of the method versus the measurement location and the TF coil 3D geometrical deformation. The analy...

  3. Failure of Magnetic Fluid Seals Operating in Water: Preliminary Conclusions

    Directory of Open Access Journals (Sweden)

    Matuszewski Leszek

    2017-06-01

    Full Text Available The article analyses properties of magnetic fluid seals installed in rotary sealing nodes which operate in the utility water environment. Seals of this type have been examined as a possible solution to the problem with ship manoeuvring propulsion sealing. The present analysis bases on laboratory durability tests of magnetic fluid seals exposed to longterm utility water loads, at different water pressures and shaft revolutions. The basic seal durability criterion was the number of revolutions made by the sealing node shaft until the appearance of water tightness loss (leakage. It was found that the main factor leading to the wear of the seal is the relative speed of the magnetic fluid with respect to that of the utility water, and this process is heavily affected by the pressure acting on the seal. The reported test results are presented in the form of diagrams showing the seal durability (time until water tightness loss as a function of rotational speed. The curves shown in the diagrams are regular, with two different rotational speed ranges: the highspeed range, when the tightness loss is relatively fast, and the low-speed range, with a clear tendency to prolong the seal lifetime. These diagrams were given the name of durability curves of the MF seal operating in water. The results of the performed tests suggest formal similarity between the experimental data distribution concerning tightness loss processes occurring in magnetic fluid seals operating in water environment and metal fatigue processes. The article proposes a preliminary simplified durability model to describe the examined phenomenon.

  4. Key engineering features of the ITER-FEAT magnet system and implications for the R&D programme

    Science.gov (United States)

    Huguet, M.; ITER Joint Central Team; ITER Home Teams

    2001-10-01

    The magnet design of the new ITER-FEAT machine comprises 18 toroidal field (TF) coils, a central solenoid (CS), 6 poloidal field coils and correction coils. A key driver of this new design is the requirement to generate and control plasmas with a relatively high elongation (κ95 = 1.7) and a relatively high triangularity (δ95 = 0.35). This has led to a design where the CS is vertically segmented and self-standing and the TF coils are wedged along their inboard legs. Another important design driver is the requirement to achieve a high operational reliability of the magnets, and this has resulted in several unconventional designs, and in particular the use of conductors supported in radial plates for the winding pack of the TF coils. A key mechanical issue is the cyclic loading of the TF coil cases due to the out-of-plane loads which result from the interaction of the TF coil current and the poloidal field. These loads are resisted by a combination of shear keys and `pre-compression' rings able to provide a centripetal preload at assembly. The fatigue life of the CS conductor jacket is another issue, as it determines the CS performance in terms of the flux generation. Two jacket materials and designs are under study. Since 1993, the ITER magnet R&D programme has been focused on the manufacture and testing of a CS and a TF model coil. During its testing, the CS model coil has successfully achieved all its performance targets in DC and AC operations. The manufacture of the TF model coil is complete. The manufacture of segments of the full scale TF coil case is another important and successful part of this programme and is near completion. New R&D effort is now being initiated to cover specific aspects of the ITER-FEAT design.

  5. A Simple and Fast Iterative Soft-thresholding Algorithm for Tight Frames in Compressed Sensing Magnetic Resonance Imaging

    CERN Document Server

    Liu, Yunsong; Cai, Jian-Feng; Guo, Di; Chen, Zhong; Qu, Xiaobo

    2015-01-01

    Compressed sensing has shown great potentials in accelerating magnetic resonance imaging. Fast image reconstruction and high image quality are two main issues faced by this new technology. It has been shown that, redundant image representations, e.g. tight frames, can significantly improve the image quality. But how to efficiently solve the reconstruction problem with these redundant representation systems is still challenging. This paper attempts to address the problem of applying fast iterative soft-thresholding algorithm (FISTA) to tight frames based magnetic resonance image reconstruction. By introducing the canonical dual frame, we construct an orthogonal projection operator on the range of the analysis sparsity operator and propose a new algorithm, called the projected FISTA (pFISTA). We theoretically prove that pFISTA converges to the minimum of a function with a balanced tight frame sparsity. One major advantage of pFISTA is that only one extra parameter, the step size, is introduced and the numerical...

  6. Computations of AC Loss in the ITER Magnets during Fast Field Transients

    CERN Document Server

    Bottura, Luca; Lister, Jonathan B; Marinucci, Claudio; Portone, Alfredo

    2007-01-01

    The calculation of AC loss due to the control currents in ITER is a cumbersome task. The reason is that control transients require small field changes (0.1 T or less) at moderate frequency (up to 10 Hz), where effects of partial penetration of the filaments and shielding are important and need to be taken into account to produce sound AC loss estimates. In this paper we describe models developed for AC loss calculation, in particular hysteresis and coupling current loss, that are suitable for the above regime. Both hysteresis and coupling loss models are adapted to the conductor analyzed through few parameters (the effective filament diameter and time constants) that can be derived from measurement of loss on short samples. We report an example of calculations of AC loss in the ITER TF and PF coils for two vertical control scenarios (VS1 and VS2) during high beta operation at flattop.

  7. Protection sequence of AC/DC converters for ITER PF MAGNET coils

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Byung Hoon; Hwang, Churl Kew; Lee, Kwang Won; Jin, Jeong Tae; Chang, Sae Sik; Oh, Jong Seok; Choi, Jung Wan; Suh, Jae Hak [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Tao, Jun; Song, In Ho [ITER Organization, Paul Lez Durance (France)

    2010-06-15

    The protection sequence of an AC/DC converter for an ITER PF coil system is developed in this study. Possible faults in the coil system are simulated and the results reflected in the design of a sequence to protect the coil and converter. The inductances of the current sharing reactors and thyristor numbers in parallel with the bridge arms are optimized with the designed protection sequence

  8. Prototyping and testing of the Continuous External Rogowski ITER magnetic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, Ph., E-mail: philippe.jacques.moreau@cea.fr [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Le-Luyer, A.; Malard, P.; Pastor, P.; Saint-Laurent, F.; Spuig, P. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Lister, J.; Toussaint, M.; Marmillod, P.; Testa, D. [Centre de Recherches en Physique des Plasmas, EPFL (Switzerland); Peruzzo, S. [Consorzio RFX, Association EURATOM-ENEA, C.so Stati Uniti 4, 35127 Padova (Italy); Knaster, J. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); IFMIF EVEDA, Rokkasho (Japan); Vayakis, G.; Hughes, S.; Patel, K.M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    Highlights: ► ITER Continuous External Rogowski (CER) are designed for plasma and vacuum vessel current measurement. ► CER are located in the casing of Toroidal Field Coils and thus will operate at 4 K. ► The design of the sensors has been completed. ► CER prototypes have been manufactured by 2 suppliers. ► The R and D campaign on CER prototypes consisted in the measurement of about 100 parameters to characterize the CER. -- Abstract: The measurement of the plasma current in ITER plays an outstanding role as it is part of the machine protection and is a safety-relevant measurement: it will be used in relation with regulatory limits to show that the operation remains within the safe envelope defined in the ITER license. The Continuous External Rogowski (CER) is an inductive sensor designed for current measurements and located in the casing of 3 Toroidal Field Coils (TFCs). After the completion of the design of the CER, 4 prototypes of the sensor were manufactured and R and D activities were performed under a Grant with the European Domestic Agency (F4E-GRT-012). The work was carried out between 2010 and 2011 by the ITERMAG consortium comprising 3 laboratories: CRPP (Switzerland) as leader, CEA (France) and RFX (Italy). The R and D campaign on CER prototypes consisted in the measurement of about 100 parameters to characterize the CER in terms of electrical, thermal, mechanical and also of vacuum compatibility. From these results, electromagnetic modeling of the CER response was performed. It is demonstrated that the CER fulfills ITER requirements. However, the vacuum compatibility of the prototype has to be improved and solutions to cope with this issue are proposed.

  9. Three-dimensional modeling of plasma edge transport and divertor fluxes during application of resonant magnetic perturbations on ITER

    Science.gov (United States)

    Schmitz, O.; Becoulet, M.; Cahyna, P.; Evans, T. E.; Feng, Y.; Frerichs, H.; Loarte, A.; Pitts, R. A.; Reiser, D.; Fenstermacher, M. E.; Harting, D.; Kirschner, A.; Kukushkin, A.; Lunt, T.; Saibene, G.; Reiter, D.; Samm, U.; Wiesen, S.

    2016-06-01

    Results from three-dimensional modeling of plasma edge transport and plasma-wall interactions during application of resonant magnetic perturbation (RMP) fields for control of edge-localized modes in the ITER standard 15 MA Q  =  10 H-mode are presented. The full 3D plasma fluid and kinetic neutral transport code EMC3-EIRENE is used for the modeling. Four characteristic perturbed magnetic topologies are considered and discussed with reference to the axisymmetric case without RMP fields. Two perturbation field amplitudes at full and half of the ITER ELM control coil current capability using the vacuum approximation are compared to a case including a strongly screening plasma response. In addition, a vacuum field case at high q 95  =  4.2 featuring increased magnetic shear has been modeled. Formation of a three-dimensional plasma boundary is seen for all four perturbed magnetic topologies. The resonant field amplitudes and the effective radial magnetic field at the separatrix define the shape and extension of the 3D plasma boundary. Opening of the magnetic field lines from inside the separatrix establishes scrape-off layer-like channels of direct parallel particle and heat flux towards the divertor yielding a reduction of the main plasma thermal and particle confinement. This impact on confinement is most accentuated at full RMP current and is strongly reduced when screened RMP fields are considered, as well as for the reduced coil current cases. The divertor fluxes are redirected into a three-dimensional pattern of helical magnetic footprints on the divertor target tiles. At maximum perturbation strength, these fingers stretch out as far as 60 cm across the divertor targets, yielding heat flux spreading and the reduction of peak heat fluxes by 30%. However, at the same time substantial and highly localized heat fluxes reach divertor areas well outside of the axisymmetric heat flux decay profile. Reduced RMP amplitudes due to screening or reduced RMP

  10. Magnetic resonance imaging urodynamics: technique development and preliminary results

    Directory of Open Access Journals (Sweden)

    Gustavo Borghesi

    2006-06-01

    Full Text Available OBJECTIVES: In this preliminary study we report the development of the video urodynamic technique using magnetic resonance imaging (MRI. MATERIALS AND METHODS: We studied 6 women with genuine stress urinary incontinence, diagnosed by history and physical examination. Urodynamic examination was performed on multichannel equipment with the patient in the supine position. Coughing and Valsalva maneuvers were performed at volumes of 150, 250 and 350 mL. Simultaneously, MRI was carried out by using 1.5 T GE Signa CV/i high-speed scanner with real time fluoroscopic imaging possibilities. Fluoroscopic imaging was accomplished in the corresponding planes with T2-weighted single shot fast spin echo sequences at a speed of about 1 frame per second. Both studies were recorded and synchronized, resulting in a single video urodynamic examination. RESULTS: Dynamic MRI with cine-loop reconstruction of 1 image per second demonstrated the movement of all compartment of the relaxed pelvis during straining with the concomitant registration of abdominal and intravesical pressures. In 5 patients, urinary leakage was demonstrated during straining and the Valsalva leak point pressure (VLPP was determined as the vesical pressure at leak subtracted from baseline bladder pressure. Mean VLPP was 72.6 cm H2O (ranging from 43 to 122 cm H2O. CONCLUSIONS: The concept of MRI video urodynamics is feasible. In a clinical perspective, practical aspects represent a barrier to daily use and it should be recommended for research purposes.

  11. Iterating skeletons

    DEFF Research Database (Denmark)

    Dieterle, Mischa; Horstmeyer, Thomas; Berthold, Jost;

    2012-01-01

    block inside a bigger structure. In this work, we present a general framework for skeleton iteration and discuss requirements and variations of iteration control and iteration body. Skeleton iteration is expressed by synchronising a parallel iteration body skeleton with a (likewise parallel) state...

  12. Accurate iterative solution of the energy eigenvalues of a two-dimensional hydrogenic donor in a magnetic field of arbitrary strength

    Energy Technology Data Exchange (ETDEWEB)

    Soylu, A. [Department of Physics, Faculty of Arts and Sciences, Erciyes University, Kayseri (Turkey) and Department of Physics, Faculty of Arts and Sciences, Nigde University, Nigde (Turkey)]. E-mail: asimsoylu@gmail.com; Boztosun, I. [Department of Physics, Faculty of Arts and Sciences, Erciyes University, Kayseri (Turkey)

    2007-06-15

    In this paper, we present the energy eigenvalues of a two-dimensional hydrogenic donor in a magnetic field by using the asymptotic iteration method. The binding energy eigenvalues in the presence of weak and strong magnetic fields ({gamma}<>0) are obtained within the framework of this iterative approach for 1S, 2P{sup -} and 3D{sup -} levels. The energy eigenvalues for the non-magnetic field case ({gamma}=0) are also determined and the results are compared with the values in weak and strong magnetic fields. The effect of the magnetic field strength on the energy eigenvalues are determined explicitly and excellent agreement with the findings of other methods is obtained.

  13. Augmented weak forms and element-by-element preconditioners: Efficient iterative strategies for structural finite elements. A preliminary study

    Science.gov (United States)

    Muller, A.; Hughes, T. J. R.

    1984-01-01

    A weak formulation in structural analysis that provides well conditioned matrices suitable for iterative solutions is presented. A mixed formulation ensures the proper representation of the problem and the constitutive relations are added in a penalized form. The problem is solved by a double conjugate gradient algorithm combined with an element by element approximate factorization procedure. The double conjugate gradient strategy resembles Uzawa's variable-length type algorithms the main difference is the presence of quadratic terms in the mixed variables. In the case of shear deformable beams these terms ensure that the proper finite thickness solution is obtained.

  14. Modeling of Self-Excited Isolated Permanent Magnet Induction Generator Using Iterative Numerical Method

    Directory of Open Access Journals (Sweden)

    Mohamed Mostafa R.

    2016-01-01

    Full Text Available Self-Excited Permanent Magnet Induction Generator (PMIG is commonly used in wind energy generation systems. The difficulty of Self-Excited Permanent Magnet Induction Generator (SEPMIG modeling is the circuit parameters of the generator vary at each load conditions due to the a change in the frequency and stator voltage. The paper introduces a new modeling for SEPMIG using Gauss-sidle relaxation method. The SEPMIG characteristics using the proposed method are studied at different load conditions according to the wind speed variation, load impedance changes and different shunted capacitor values. The system modeling is investigated due to the magnetizing current variation, the efficiency variation, the power variation and power factor variation. The proposed modeling system satisfies high degree of simplicity and accuracy.

  15. Transient Behaviour of Superconducting Magnet Systems of Fusion Reactor ITER during Safety Discharge

    Directory of Open Access Journals (Sweden)

    A. M. Miri

    2008-01-01

    Full Text Available To investigate the transient behaviour of the toroidal and poloidal field coils magnet systems of the International Thermonuclear Experimental Reactor during safety discharge, network models with lumped elements are established. Frequency-dependant values of the network elements, that is, inductances and resistances are calculated with the finite element method. That way, overvoltages can be determined. According to these overvoltages, the insulation coordination of coils has to be selected.

  16. Iterating skeletons

    DEFF Research Database (Denmark)

    Dieterle, Mischa; Horstmeyer, Thomas; Berthold, Jost;

    2012-01-01

    Skeleton-based programming is an area of increasing relevance with upcoming highly parallel hardware, since it substantially facilitates parallel programming and separates concerns. When parallel algorithms expressed by skeletons involve iterations – applying the same algorithm repeatedly...... block inside a bigger structure. In this work, we present a general framework for skeleton iteration and discuss requirements and variations of iteration control and iteration body. Skeleton iteration is expressed by synchronising a parallel iteration body skeleton with a (likewise parallel) state......-based iteration control, where both skeletons offer supportive type safety by dedicated types geared towards stream communication for the iteration. The skeleton iteration framework is implemented in the parallel Haskell dialect Eden. We use example applications to assess performance and overhead....

  17. Alfven eigenmode stability and fast ion loss in DIII-D and ITER reversed magnetic shear plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Van Zeeland, Michael [General Atomics; Gorelenkov, Nikolai [Princeton Plasma Physics Laboratory (PPPL); Heidbrink, W. [University of California, Irvine; Kramer, G. [Princeton Plasma Physics Laboratory (PPPL); Spong, Donald A [ORNL; Austin, M. E. [University of Texas, Austin; Fisher, R K [General Atomics, San Diego; Munoz, M G [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, Garching, Germany; Gorelenkova, M. [Princeton Plasma Physics Laboratory (PPPL); Luhmann, N.C. [University of California, Davis; Murakami, Masanori [ORNL; Nazikian, Raffi [Princeton Plasma Physics Laboratory (PPPL); Park, J. M. [Oak Ridge National Laboratory (ORNL); Tobias, Ben [University of California, Davis; White, R. [Princeton Plasma Physics Laboratory (PPPL)

    2012-01-01

    Neutral beam injection into reversed-magnetic shear DIII-D plasmas produces a variety of Alfvenic activity including toroidicity-induced Alfven eigenmodes (TAEs) and reversed shear Alfven eigenmodes (RSAEs). With measured equilibrium profiles as inputs, the ideal MHD code NOVA is used to calculate eigenmodes of these plasmas. The postprocessor code NOVA-K is then used to perturbatively calculate the actual stability of the modes, including finite orbit width and finite Larmor radius effects, and reasonable agreement with the spectrum of observed modes is found. Using experimentally measured mode amplitudes, fast ion orbit following simulations have been carried out in the presence of the NOVA calculated eigenmodes and are found to reproduce the dominant energy, pitch and temporal evolution of the losses measured using a large bandwidth scintillator diagnostic. The same analysis techniques applied to a DT 8 MA ITER steady-state plasma scenario with reversed-magnetic shear and both beam ion and alpha populations show Alfven eigenmode instability. Both RSAEs and TAEs are found to be unstable with maximum growth rates occurring for toroidal mode number n = 6 and the majority of the drive coming from fast ions injected by the 1MeV negative ion beams. AE instability due to beam ion drive is confirmed by the non-perturbative code TAEFL. Initial fast ion orbit following simulations using the unstable modes with a range of amplitudes (delta B/B = 10(-5)-10(-3)) have been carried out and show negligible fast ion loss. The lack of fast ion loss is a result of loss boundaries being limited to large radii and significantly removed from the actual modes themselves.

  18. Design of Pulsed Strong Magnetic Fields Generator and Preliminary Application

    Institute of Scientific and Technical Information of China (English)

    WEN Jun; QU Xue-min; WANG Xi-gang; LONG Kai-ping

    2015-01-01

    Objective: This paper aims to designing a pulsed strong magnetic fields generator. Methods: A large value capacitor was used to store electric energy, coil was used for producing magnetic fields, main control, circuit control charge, sampling, discharge, etc. Results: The generator provided a pulsed magnetic field with the ampli-tude of intensity from 0.1-2 T and variable time interval of pulse from 4 s-1 min. It was not only to be operated easily but also performed reliably. Conclusion:The generator will be applied in special clinical diagnosis, therapy and other fields.

  19. A Preliminary Study on Paleomagnetism and Rock Magnetism of Eclogite from the Maobei Area

    Institute of Scientific and Technical Information of China (English)

    Meng Xiaohong; Yu Qinfan; GuoYouzhao; Zhou Yaoxiu

    2007-01-01

    A preliminary study of paleomagnetism and rock magnetism has been done on 55 eclogite samples collected from the Chinese Continental Scientific Drilling (CCSD) site at the Maobei (毛北) area,Donghai (东海) County, Jiangsu (江苏) Province. Also the isothermal remanence, hysteresis loop, magnetic fabric, thermal susceptibility were measured, and analyses were made by electron-probe and scanning electric microscope on some samples synchronously. The result indicates that there are two groups of stable remanence, the normal and reversed magnetization. The remanence orientations are: D=94.3°, I=-29.1° and D=273.7°, I=15.4°, respectively. The magnetization intensity and the density of the samples which carry the normal magnetization are very different from those bearing reversed magnetization. The magnetic anisotropy is weak, and the minimum axis is hardly determined. The isothermal remanence and the hysteresis loop show that the magnetic carriers of the eclogite are likely SD (single domain) and PSD(pseudo-single domain) magnetite. According to the magnetic property, the cause of formation of magnetic carriers, the mechanism of the remanence, and the significance for the tectonics are discussed.

  20. Simulation experiment of interaction of plasma facing materials and transient heat loads in ITER divertor by use of magnetized coaxial plasma gun

    Science.gov (United States)

    Nakatsuka, M.; Ando, K.; Higashi, T.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2009-11-01

    Interaction of plasma facing materials and transient head loads such as type I ELMs is one of the critical issues in ITER divertor. The heat load to the ITER divertor during type I ELMs is estimated to be 0.5-3 MJ/m^2 with a pulse length of 0.1-0.5 ms. We have developed a magnetized coaxial plasma gun (MCPG) for the simulation experiment of transient heat load during type I ELMs in ITER divertor. The MCPG has inner and outer electrodes made of stainless steel 304. In addition, the inner electrode is covered with molybdenum so as to suppress the release of impurities from the electrode during the discharge. The diameters of inner and outer electrodes are 0.06 m and 0.14 m, respectively. The power supply for the MCPG is a capacitor bank (7 kV, 1 mF, 25 kJ). The plasma velocity estimated by the time of flight measurement of the magnetic fields was about 50 km/s, corresponding to the ion energy of 15 eV (H) or 30 eV (D). The absorbed energy density of the plasma stream was measured a calorimeter made of graphite. It was found that the absorbed energy density was 0.9 MJ/m^2 with a pulse width of 0.5 ms at the distance of 100 mm from the inner electrode. In the conference, experimental results of plasma exposure on the plasma facing materials in ITER divertor will be shown.

  1. Installation of the Main Magnet and Preliminary Results of Magnetic Mapping and Shimming for CYCIAE-100

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Tian-jue; LV; Yin-long; ZHONG; Jun-qing; XING; Jian-sheng; CAO; Lei; YANG; Jian-jun; WANG; Chuan; YAO; Hong-juan; CUI; Tao; LI; Ming; YIN; Zhi-guo; WANG; Zhen-hui; LIU; Geng-shou; LEI; Yu; ZOU; Jian; ZHAO; Jiang-bin

    2012-01-01

    <正>In 2012, the magnetic mapping and shimming for the main magnet of CYCIAE-100 has been carried out 4 times in the temporary building, realizing the goal of reducing the phase shift of the accelerating proton by 80%. A number of large scale equipments, including the main magnet, main coils, hydraulic elevating system, RF amplifier, magnetic mapper and vacuum chamber, have been in place for installation in the main building. The final stage magnetic mapping and shimming has started out as well.

  2. DYNAMIC MAGNETIC RESONANCE IMAGING: PRELIMINARY PRESENTATION OF A TECHNIQUE

    Directory of Open Access Journals (Sweden)

    BRUNO DA COSTA ANCHESCHI

    Full Text Available ABSTRACT Objective: To evaluate morphometric variations of the cervical spine in patients with cervical spondylotic myelopathy (CSM using dynamic magnetic resonance imaging (MRI in neutral, flexion and extension positions. Methods: This is a prospective study of patients with CSM secondary to degenerative disease of the cervical spine. The morphometric parameters were evaluated using T2-weighted MRI sequences in the sagittal plane in neutral, flexion and extension position of the neck. The parameters studied were the anterior length of the spinal cord (ALSC, the posterior length of the spinal cord (PLSC, the diameter of the vertebral canal (DVC and the diameter of the spinal cord (DSC. Results: The ALSC and PLSC were longer in flexion than in extension and neutral position, with statistically significant difference between the flexion and extension position. The DVC and the DSC were greater in flexion than in extension and neutral position, however, there was no statistically significant difference when they were compared in the neutral, flexion and extension positions. Conclusion: Dynamic MRI allows to evaluate morphometric variations in the cervical spinal canal in patients with cervical spondylotic myelopathy.

  3. Magnetization transfer imaging of normal and abnormal testis: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Tsili, Athina C.; Ntorkou, Alexandra; Maliakas, Vasilios; Argyropoulou, Maria I. [University of Ioannina, Department of Clinical Radiology, Medical School, Ioannina (Greece); Baltogiannis, Dimitrios; Sylakos, Anastasios; Sofikitis, Nikolaos [University of Ioannina, Department of Urology, Medical School, Ioannina (Greece); Stavrou, Sotirios [University of Ioannina, Department of Urology, Medical School, Ioannina (Greece); University Hospital of Ioannina, Leoforos S. Niarchou, Department of Urology, Ioannina (Greece); Astrakas, Loukas G. [University of Ioannina, Department of Medical Physics, Medical School, Ioannina (Greece)

    2016-03-15

    The aim was to determine the magnetization transfer ratio (MTR) of normal testes, possible variations with age and to assess the feasibility of MTR in characterizing various testicular lesions. Eighty-six men were included. A three-dimensional gradient-echo MT sequence was performed, with/without an on-resonance binomial prepulse. MTR was calculated as: (SIo-SIm)/(SIo) x 100 %, where SIm and SIo refers to signal intensities with and without the saturation pulse, respectively. Subjects were classified as: group 1, 20-39 years; group 2, 40-65 years; and group 3, older than 65 years of age. Analysis of variance (ANOVA) followed by the least significant difference test was used to assess variations of MTR with age. Comparison between the MTR of normal testis, malignant and benign testicular lesions was performed using independent-samples t testing. ANOVA revealed differences of MTR between age groups (F = 7.51, P = 0.001). Significant differences between groups 1, 2 (P = 0.011) and 1, 3 (P < 0.001) were found, but not between 2, 3 (P = 0.082). The MTR (in percent) of testicular carcinomas was 55.0 ± 3.2, significantly higher than that of benign lesions (50.3 ± 4.0, P = 0.02) and of normal testes (47.4 ± 2.2, P < 0.001). MTR of normal testes decreases with age. MTR might be helpful in the diagnostic work-up of testicular lesions. (orig.)

  4. Preliminary investigation of force-reduced superconducting magnet configurations for advanced technology applications

    Energy Technology Data Exchange (ETDEWEB)

    Bouillard, J.X.

    1992-12-01

    The feasibility of new high-field low specific weight superconducting magnet designs using force-free fields is being explored analytically and numerically. This report attempts to assess the technical viability of force-free field concepts to produce high-field, low specific weight and large bore volume magnets, which could promote the use of high temperature superconductors. Several force-free/force-reduced magnet configurations are first reviewed, then discussed and assessed. Force-free magnetic fields, fields for which the current flows parallel to the field, have well-known mathematical solutions extending upon infinite domains. These solutions, however, are no longer force-free everywhere for finite geometries. In this preliminary study, force-free solutions such as the Lundquist solutions truncated to a size where the internal field of the coil matches an externally cylindrical magnetic field (also called a Lundquist coil) are numerically modeled and explored. Significant force-reduction for such coils was calculated, which may have some importance for the design of lighter toroidal magnets used in thermonuclear fusion power generation, superconducting magnetic energy storage (SMES), and mobile MHD power generation and propulsion.

  5. Fetal magnetic resonance imaging: jumping from 1.5 to 3 tesla (preliminary experience)

    Energy Technology Data Exchange (ETDEWEB)

    Victoria, Teresa [The Children' s Hospital of Philadelphia, Radiology Department, Center for Fetal Diagnosis and Treatment, Philadelphia, PA (United States); Jaramillo, Diego; Roberts, Timothy Paul Leslie; Zarnow, Deborah; Johnson, Ann Michelle; Delgado, Jorge; Vossough, Arastoo [The Children' s Hospital of Philadelphia, Radiology Department, Philadelphia, PA (United States); Rubesova, Erika [Stanford University, Department of Radiology, Lucile Packard Children' s Hospital, Stanford, CA (United States)

    2014-04-15

    Several attempts have been made at imaging the fetus at 3 T as part of the continuous search for increased image signal and better anatomical delineation of the developing fetus. Until very recently, imaging of the fetus at 3 T has been disappointing, with numerous artifacts impeding image analysis. Better magnets and coils and improved technology now allow imaging of the fetus at greater magnetic strength, some hurdles in the shape of imaging artifacts notwithstanding. In this paper we present the preliminary experience of evaluating the developing fetus at 3 T and discuss several artifacts encountered and techniques to decrease them, as well as safety concerns associated with scanning the fetus at higher magnetic strength. (orig.)

  6. Magnetic resonance findings in amyotrophic lateral sclerosis using a spin echo magnetization transfer sequence: preliminary report

    Directory of Open Access Journals (Sweden)

    ROCHA ANTÔNIO JOSÉ DA

    1999-01-01

    Full Text Available We present the magnetic resonance (MR findings of five patients with amyotrophic lateral sclerosis (ALS using a spin-echo sequence with an additional magnetization transfer (MT pulse on T1-weighted images (T1 SE/MT. These findings were absent in the control group and consisted of hyperintensity of the corticospinal tract. Moreover we discuss the principles and the use of this fast but simple MR technique in the diagnosis of ALS

  7. Preliminary magnetostratigraphy and environmental magnetism of the Lower Cretaceous from the Italian Dolomites

    Science.gov (United States)

    Savian, J. F.; Jovane, L.; Florindo, F.; Lukeneder, A.

    2011-12-01

    The Lower Cretaceous (~146 to 100 Ma) represents an enigmatic time interval for paleoclimatic, paleogeography and paleomagnetic evolution of the Earth's history. The climatic changes include global oceanic anoxic events (OAEs), biotic changes, global excursions of carbon and strontium isotopes, rises in eustatic sea level and paleotemperature. Paleoceanography was marked by a rapid rate of ocean spreading in the Atlantic. The opening of the Atlantic Ocean was wide enough to allow significant circulation of masses of waters across the equator. This period is furthermore important for the oceanographic events occurring at the base of the Aptian (Selli Level). This period also present one of the most intriguing geomagnetic events: the long normal Cretaceous superchron, lasted for almost 40 million years. We study here the lower Cretaceous deposits of the Puez section in the Dolomites (northern Italy) which represents a continuous section during this period. The samples collected represent marine sedimentary materials of the Biancone and Puez formations. The Puez section consists essentially of green-grey to red limestones and calcareous marls. We present preliminary results of integrated magnetostratigraphic analysis, including a detailed lithostratigraphy and environmental magnetism. We recognize magnetic behavior that are relative to normal polarity (the normal Cretaceous superchron), with a short reverse interval that might represent the M-1r event. We also recognize a series of normal and reverse polarities (below the normal Cretaceous superchron) which can be referred to the magnetozones M1/M5. The environmental magnetic data consists of magnetic susceptibility (χ), natural remanent magnetization (NRM), anhysteretic remanent magnetization (ARM), isothermal remanent magnetization (IRM) at 900 mT and backfield isothermal remanent magnetization (BIRM) at 100 mT and 300 mT. Derived parameters, such as S-ratio (S300=BIRM300/IRM900) and hard isothermal remanent

  8. Runaway electrons and ITER

    Science.gov (United States)

    Boozer, Allen H.

    2017-05-01

    The potential for damage, the magnitude of the extrapolation, and the importance of the atypical—incidents that occur once in a thousand shots—make theory and simulation essential for ensuring that relativistic runaway electrons will not prevent ITER from achieving its mission. Most of the theoretical literature on electron runaway assumes magnetic surfaces exist. ITER planning for the avoidance of halo and runaway currents is focused on massive-gas or shattered-pellet injection of impurities. In simulations of experiments, such injections lead to a rapid large-scale magnetic-surface breakup. Surface breakup, which is a magnetic reconnection, can occur on a quasi-ideal Alfvénic time scale when the resistance is sufficiently small. Nevertheless, the removal of the bulk of the poloidal flux, as in halo-current mitigation, is on a resistive time scale. The acceleration of electrons to relativistic energies requires the confinement of some tubes of magnetic flux within the plasma and a resistive time scale. The interpretation of experiments on existing tokamaks and their extrapolation to ITER should carefully distinguish confined versus unconfined magnetic field lines and quasi-ideal versus resistive evolution. The separation of quasi-ideal from resistive evolution is extremely challenging numerically, but is greatly simplified by constraints of Maxwell’s equations, and in particular those associated with magnetic helicity. The physics of electron runaway along confined magnetic field lines is clarified by relations among the poloidal flux change required for an e-fold in the number of electrons, the energy distribution of the relativistic electrons, and the number of relativistic electron strikes that can be expected in a single disruption event.

  9. Summary of the International Workshop on Magnetic Fusion Energy (MFE) Roadmapping in the ITER Era; 7-10 September 2011, Princeton, NJ, USA

    Science.gov (United States)

    Neilson, G. H.; Federici, G.; Li, J.; Maisonnier, D.; Wolf, R.

    2012-04-01

    With the ITER project now well under way, the countries engaged in fusion research are planning, with renewed intensity, the research and major facilities needed to develop the science and technology for harnessing fusion energy. The Workshop on MFE Roadmapping in the ITER Era was organized to provide a timely forum for an international exchange of technical information and strategic perspectives on how best to tackle the remaining challenges leading to a magnetic fusion DEMO, a nuclear fusion device or devices with a level of physics and technology integration necessary to cover the essential elements of a commercial fusion power plant. Presentations addressed issues under four topics: (1) Perspectives on DEMO and the roadmap to DEMO; (2) Technology; (3) Physics-Technology integration and optimization; and (4) Major facilities on the path to DEMO. Participants identified a set of technical issues of high strategic importance, where the development strategy strongly influences the overall roadmap, and where there are divergent understandings in the world community, namely (1) the assumptions used in fusion design codes, (2) the strategy for fusion materials development, (3) the strategy for blanket development, (4) the strategy for plasma exhaust solution development and (5) the requirements and state of readiness for next-step facility options. It was concluded that there is a need to continue and to focus the international discussion concerning the scientific and technical issues that determine the fusion roadmap, and it was suggested that an international activity be organized under appropriate auspices to foster international cooperation on these issues.

  10. Waves in 3D Magnetic Nulls: some preliminary results in the PPT device and in situ Measurements in the Magnetosphere

    Science.gov (United States)

    Xiao, Chijie; Yang, Xiaoyi; Chen, Yangao; Chen, Yihang; Wang, Xiaogang

    2015-11-01

    Plasma waves and the particle dynamics in the magnetic null are very important to understand the three-dimensional (3D) magnetic reconnection process. A small plasma device, which named PPT device (abbreviated form of PKU Plasma Test device), has setup recently to study the waves and particle dynamics around a magnetic null. Here we will report the first preliminary results, such as the waves along the spines and the fan surfaces, as well as the particle dynamics around it. Furthermore, some wave modes around 3D nulls detected by Cluster mission in the magnetosphere will also be reported to compare. These preliminary results will give more clues to understanding of the magnetic nulls and 3D magnetic reconnection.

  11. Preliminary Geochemical and Rock Magnetic Study of a Stalagmite From Quintana Roo, Northeastern Yucatan Peninsula

    Science.gov (United States)

    Urrutia-Fucugauchi, J.; Perez-Cruz, L.; Zhao, X.; Rebolledo-Vieyra, M.; Rodriguez, A.

    2012-04-01

    We present the preliminary results of geochemical, stable isotopes and rock magnetic studies of a stalagmite from a cave in eastern Quintana Roo, northern Yucatan peninsula. In the past years, there has been increased interest in understanding the paleoclimatic and paleoenvironmental evolution of the Yucatan peninsula and northern Central America, investigating the relationships between climate variations and the development of the Maya civilization. In particular, the variations in regional precipitation and occurrence of several drought periods, which might have been related to the collapse of the Classic Maya period. Stable isotope data on speleothems from different sites in Yucatan and Central America have provided evidence on changes in precipitation, which have affected the Maya region. The stalagmite is ~47 cm long and about 4-5 cm wide at its base. It was collected from the Hilariós Well cave in Tulum, Quintana Roo. Magnetic susceptibility and geochemical analyses have been completed as part of the initial characterization of the stalagmite, with measurements taken every centimeter. Geochemical analyses have been carried out for x-ray fluorescence, with a Niton XRF analyzer. Magnetic susceptibility was determined with a Bartington MS2 instrument using the high resolution surface probe. Additional rock magnetic analyses include magnetic hysteresis loops and isothermal remanent magnetization (IRM) acquisition, and saturation IRM demagnetization, which have been measured with a MicroMag instrument. Hysteresis loops are diamagnetic, with small varying low-coercivity ferromagnetic components. The elemental compositions of major oxides and trace elements vary with depth. Calcium is the major element and displays a pattern of small amplitude fluctuations with a trend to lower values at the bottom, which are also shown in other elements such as barium. Silica and elements such as titanium and strontium are positively correlated and show an apparent cyclic pattern

  12. Runaway electrons and ITER

    Science.gov (United States)

    Boozer, Allen

    2016-10-01

    ITER planning for avoiding runaway damage depends on magnetic surface breakup in fast relaxations. These arise in thermal quenches and in the spreading of impurities from massive gas injection or shattered pellets. Surface breakup would prevent a runaway to relativistic energies were it not for non-intercepting flux tubes, which contain magnetic field lines that do not intercept the walls. Such tubes persist near the magnetic axis and in the cores of islands but must dissipate before any confining surfaces re-form. Otherwise, a highly dangerous situation arises. Electrons that were trapped and accelerated in these flux tubes can fill a large volume of stochastic field lines and serve as a seed for the transfer of the full plasma current to runaways. If the outer confining surfaces are punctured, as by a drift into the wall, then the full runaway inventory will be lost in a short pulse along a narrow flux tube. Although not part of ITER planning, currents induced in the walls by the fast magnetic relaxation could be used to passively prevent outer surfaces re-forming. If magnetic surface breakup can be avoided during impurity injection, the plasma current could be terminated in tens of milliseconds by plasma cooling with no danger of runaway. Support by DoE Office of Fusion Energy Science Grant De-FG02-03ER54696.

  13. Magnetization and loss measurements on Nb3Sn and NbTi strands for ITER and LHC

    CERN Document Server

    Foitl, M

    2001-01-01

    Recent developments in high energy physics have led to a demand for high magnetic fields which cannot be generated permanently by conventional magnets wound from Cu cables. The acceleration of protons in a ring accelerator up to particle energies of several TeVs or the magnetic confinement of fusion plasmas of sufficient pressure to generate approx 1 GW of fusion power, or even more, are only two examples. To reach beam to beam collision energies of several TeV for hadrons or heavy ions, accelerator magnets have to provide very high magnetic fields which can only be produced by superconducting magnets. In the case of the Large Hadron Collider (LHC), which is planned to be commissioned in the year 2005, the circumference of the beam line is given by the dimensions of the 27 Km Large Electron Positron (LEP) Collider tunnel. Consequently each superconducting arc dipole has to provide a field of 8.36 T to bend 7 TeV protons around the ring. Apart from the total magnitude of the bending field, which necessitates t...

  14. Updated safety analysis of ITER

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Neill, E-mail: neill.taylor@iter.org [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Baker, Dennis; Ciattaglia, Sergio; Cortes, Pierre; Elbez-Uzan, Joelle; Iseli, Markus; Reyes, Susana; Rodriguez-Rodrigo, Lina; Rosanvallon, Sandrine; Topilski, Leonid [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France)

    2011-10-15

    An updated version of the ITER Preliminary Safety Report has been produced and submitted to the licensing authorities. It is revised and expanded in response to requests from the authorities after their review of an earlier version in 2008, to reflect enhancements in ITER safety provisions through design changes, to incorporate new and improved safety analyses and to take into account other ITER design evolution. The updated analyses show that changes to the Tokamak cooling water system design have enhanced confinement and reduced potential radiological releases as well as removing decay heat with very high reliability. New and updated accident scenario analyses, together with fire and explosion risk analyses, have shown that design provisions are sufficient to minimize the likelihood of accidents and reduce potential consequences to a very low level. Taken together, the improvements provided a stronger demonstration of the very good safety performance of the ITER design.

  15. Preliminary interpretation of satellite gravity and magnetic anomalies in the region of the Philippine Sea Plate

    Science.gov (United States)

    Chen, C.; Hu, Z.; Du, J.; Wang, Q.

    2011-12-01

    The Philippine Sea, situated in the northwestern Pacific, is one of the largest marginal seas on the Earth. Analysis of the Philippine Sea's intraplate fault tectonic systems and lithosphere's density and magnetism structures has a significant contribution to understanding not only the dynamic principles of subduction and convergence zones but also effect of plate subduction on back-arc area. It is also important to have cognizance for structure evolution of the ocean crust, the tension and extending progress of marginal sea basins and the mechanisms of geodynamics. Meanwhile, it can be a significant approach for researching the evolution of the East China Sea and the South China Sea. Using high-precision gravity forwarding method based on spatial domain in spherical coordinate, we have calculated the Bouguer gravity disturbance (BGD) in the Philippine Sea based on the ETOPO1 1 arc-minute topography & bathymetry data and the gravity field model EIGEN-6C. After removing the gravity effect of the sediments and deep abnormal materials, we make spherical cap harmonic analysis of the residual anomaly and obtain the topography of Moho and apparent-density's distribution of our study area by alternate iteration inversion method. Then, we calculate the distributions of the study area's magnetic anomalies based on the Earth magnetic model NGDC720, reduce to the pole of the study area's magnetic anomalies by the equivalent source method based on spherical prism magnetic forwarding, inverse the processed magnetic anomalies with spherical cap harmonic analysis to obtain the topography of Curie surface and the apparent magnetic susceptibility distribution. Finally, we divide the Philippine Sea block into tectonic units and derive the faults distributions through the analysis of gravity magnetic anomalies' linear characteristics. The results show that West Philippine Basin is divided by Central Basin Ridge into two block units, the tectonic trend of the north block is south

  16. The first fusion reactor: ITER

    Science.gov (United States)

    Campbell, D. J.

    2016-11-01

    Established by the signature of the ITER Agreement in November 2006 and currently under construction at St Paul-lez-Durance in southern France, the ITER project [1,2] involves the European Union (including Switzerland), China, India, Japan, the Russian Federation, South Korea and the United States. ITER (`the way' in Latin) is a critical step in the development of fusion energy. Its role is to provide an integrated demonstration of the physics and technology required for a fusion power plant based on magnetic confinement.

  17. Status of ITER Cryodistribution and Cryoline project

    Science.gov (United States)

    Sarkar, B.; Vaghela, H.; Shah, N.; Bhattacharya, R.; Choukekar, K.; Patel, P.; Kapoor, H.; Srinivasa, M.; Chang, H. S.; Badgujar, S.; Monneret, E.

    2017-02-01

    The system of ITER Cryodistribution (CD) and Cryolines (CLs) is an integral interface between the Cryoplant systems and the superconducting (SC) magnets as well as Cryopumps (CPs). The project has progressed from the conceptual stage to the industrial stage. The subsystems are at various stages of design as defined by the project, namely, preliminary design, final design and formal reviews. Significant progresses have been made in the prototypes studies and design validations, such as the CL and cold circulators. While one of the prototype CL is already tested, the other one is in manufacturing phase. Performance test of two cold circulators have been completed. Design requirements are unique due the complexity arising from load specifications, layout constraints, regulatory compliance, operating conditions as well as several hundred interfaces. The present status of the project in terms of technical achievements, implications of the changes and the technical management as well as the risk assessment and its mitigation including path forward towards realization is described.

  18. Synthesis, Characterization, and Preliminary Investigation of Cell Interaction of Magnetic Nanoparticles with Catechol-Containing Shells

    Science.gov (United States)

    Wagner, Kerstin; Seemann, Thomas; Wyrwa, Ralf; Clement, Joachim H.; Müller, Robert; Nietzsche, Sandor; Schnabelrauch, Matthias

    2010-12-01

    Superparamagnetic iron oxide cores were synthesized by co-precipitation of Fe(II) and Fe(III) salts and subsequently stabilized by coating with different catechols (levodopa, dopamine, hydrocaffeic acid, dopamine-containing carboxymethyl dextran) known to act as high-affinity, bidentate ligands for Fe(III). The prepared stable magnetic fluids were characterized with regard to their chemical composition (content of iron and shell material, Fe(II)/Fe(III) ratio) and their physical properties (size, surface charge, magnetic parameters). The nanoparticles showed no or only slight cytotoxic effects within 1 and 4 days of incubation with 3T3 fibroblast cells. Preliminary experiments were performed to study the interaction of the prepared nanoparticles with human MCF-7 breast cancer cells and leukocytes. An intense interaction of the MCF-7 cells with these particles was found whereas the leukocytes showed a lower tendency of interaction. Based on these finding, the novel magnetic nanoparticles possess the potential for use in depletion of tumor cells from peripheral blood.

  19. Cortical gyrification in autistic and Asperger disorders: a preliminary magnetic resonance imaging study.

    Science.gov (United States)

    Jou, Roger J; Minshew, Nancy J; Keshavan, Matcheri S; Hardan, Antonio Y

    2010-12-01

    The validity of Asperger disorder as a distinct syndrome from autism is unclear partly because of the paucity of differentiating neurobiological evidence. Frontal lobe cortical folding between these disorders was compared using the gyrification index. Twenty-three boys underwent structural magnetic resonance imaging: 6 with high-functioning autism, 9 with Asperger disorder, and 8 controls. Using the first coronal slice anterior to the corpus callosum, total and outer cortical contours were traced to calculate the gyrification index. This index was also calculated for superior and inferior regions to examine dorsolateral prefrontal and orbitofrontal cortices, respectively. Analysis of variance revealed differences in the left inferior gyrification index, which was higher in the autism group compared with Asperger and control groups. There were no differences in age, intelligence quotient, and brain volume. These preliminary findings suggest that cortical folding may be abnormally high in the frontal lobe in autism but not Asperger disorder, suggesting distinct frontal lobe neuropathology.

  20. Validation of the model for ELM suppression with 3D magnetic fields using low torque ITER baseline scenario discharges in DIII-D

    Science.gov (United States)

    Moyer, R. A.; Paz-Soldan, C.; Nazikian, R.; Orlov, D. M.; Ferraro, N. M.; Grierson, B. A.; Knölker, M.; Lyons, B. C.; McKee, G. R.; Osborne, T. H.; Rhodes, T. L.; Meneghini, O.; Smith, S.; Evans, T. E.; Fenstermacher, M. E.; Groebner, R. J.; Hanson, J. M.; La Haye, R. J.; Luce, T. C.; Mordijck, S.; Solomon, W. M.; Turco, F.; Yan, Z.; Zeng, L.; DIII-D Team

    2017-10-01

    Experiments have been executed in the DIII-D tokamak to extend suppression of Edge Localized Modes (ELMs) with Resonant Magnetic Perturbations (RMPs) to ITER-relevant levels of beam torque. The results support the hypothesis for RMP ELM suppression based on transition from an ideal screened response to a tearing response at a resonant surface that prevents expansion of the pedestal to an unstable width [Snyder et al., Nucl. Fusion 51, 103016 (2011) and Wade et al., Nucl. Fusion 55, 023002 (2015)]. In ITER baseline plasmas with I/aB = 1.4 and pedestal ν* ˜ 0.15, ELMs are readily suppressed with co- Ip neutral beam injection. However, reducing the beam torque from 5 Nm to ≤ 3.5 Nm results in loss of ELM suppression and a shift in the zero-crossing of the electron perpendicular rotation ω⊥e ˜ 0 deeper into the plasma. The change in radius of ω⊥e ˜ 0 is due primarily to changes to the electron diamagnetic rotation frequency ωe*. Linear plasma response modeling with the resistive MHD code m3d-c1 indicates that the tearing response location tracks the inward shift in ω⊥e ˜ 0. At pedestal ν*˜ 1, ELM suppression is also lost when the beam torque is reduced, but the ω⊥e change is dominated by collapse of the toroidal rotation vT. The hypothesis predicts that it should be possible to obtain ELM suppression at reduced beam torque by also reducing the height and width of the ωe* profile. This prediction has been confirmed experimentally with RMP ELM suppression at 0 Nm of beam torque and plasma normalized pressure βN ˜ 0.7. This opens the possibility of accessing ELM suppression in low torque ITER baseline plasmas by establishing suppression at low beta and then increasing beta while relying on the strong RMP-island coupling to maintain suppression.

  1. Whole-organ CT perfusion of the pancreas: impact of iterative reconstruction on image quality, perfusion parameters and radiation dose in 256-slice CT-preliminary findings.

    Directory of Open Access Journals (Sweden)

    Qian Xie

    Full Text Available BACKGROUND: This study was performed to assess whether iterative reconstruction can reduce radiation dose while maintaining acceptable image quality, and to investigate whether perfusion parameters vary from conventional filtered back projection (FBP at the low-tube-voltage (80-kVp during whole-pancreas perfusion examination using a 256-slice CT. METHODS: 76 patients with known or suspected pancreatic mass underwent whole-pancreas perfusion by a 256-slice CT. High- and low-tube-voltage CT images were acquired. 120-kVp image data (protocol A and 80-kVp image data (protocol B were reconstructed with conventional FBP, and 80-kVp image data were reconstructed with iDose(4 (protocol C iterative reconstruction. The image noise; contrast-to-noise ratio (CNR relative to muscle for the pancreas, liver, and aorta; and radiation dose of each protocol were assessed quantitatively. Overall image quality was assessed qualitatively. Among 76 patients, 23 were eventually proven to have a normal pancreas. Perfusion parameters of normal pancreas in each protocol including blood volume, blood flow, and permeability-surface area product were measured. RESULTS: In the quantitative study, protocol C reduced image noise by 36.8% compared to protocol B (P<0.001. Protocol C yielded significantly higher CNR relative to muscle for the aorta, pancreas and liver compared to protocol B (P<0.001, and offered no significant difference compared to protocol A. In the qualitative study, protocols C and A gained similar scores and protocol B gained the lowest score for overall image quality (P<0.001. Mean effective doses were 23.37 mSv for protocol A and 10.81 mSv for protocols B and C. There were no significant differences in the normal pancreas perfusion values among three different protocols. CONCLUSION: Low-tube-voltage and iDose(4 iterative reconstruction can dramatically decrease the radiation dose with acceptable image quality during whole-pancreas CT perfusion and have no

  2. Scan time reduction in {sup 23}Na-Magnetic Resonance Imaging using the chemical shift imaging sequence. Evaluation of an iterative reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Weingaertner, Sebastian; Konstandin, Simon; Schad, Lothar R. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Wetterling, Friedrich [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Dublin Univ. (Ireland) Trinity Inst. of Neuroscience; Fatar, Marc [Heidelberg Univ., Mannheim (Germany). Dept. of Neurology; Neumaier-Probst, Eva [Heidelberg Univ., Mannheim (Germany). Dept. of Neuroradiology

    2015-07-01

    To evaluate potential scan time reduction in {sup 23}Na-Magnetic Resonance Imaging with the chemical shift imaging sequence (CSI) using undersampled data of high-quality datasets, reconstructed with an iterative constrained reconstruction, compared to reduced resolution or reduced signal-to-noise ratio. CSI {sup 23}Na-images were retrospectively undersampled and reconstructed with a constrained reconstruction scheme. The results were compared to conventional methods of scan time reduction. The constrained reconstruction scheme used a phase constraint and a finite object support, which was extracted from a spatially registered {sup 1}H-image acquired with a double-tuned coil. The methods were evaluated using numerical simulations, phantom images and in-vivo images of a healthy volunteer and a patient who suffered from cerebral ischemic stroke. The constrained reconstruction scheme showed improved image quality compared to a decreased number of averages, images with decreased resolution or circular undersampling with weighted averaging for any undersampling factor. Brain images of a stroke patient, which were reconstructed from three-fold undersampled k-space data, resulted in only minor differences from the original image (normalized root means square error < 12%) and an almost identical delineation of the stroke region (mismatch < 6%). The acquisition of undersampled {sup 23}Na-CSI images enables up to three-fold scan time reduction with improved image quality compared to conventional methods of scan time saving.

  3. The ITER project construction status

    Science.gov (United States)

    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.

  4. The 6 April 2009 earthquake at L'Aquila: a preliminary analysis of magnetic field measurements

    Directory of Open Access Journals (Sweden)

    U. Villante

    2010-02-01

    Full Text Available Several investigations reported the possible identification of anomalous geomagnetic field signals prior to earthquake occurrence. In the ULF frequency range, candidates for precursory signatures have been proposed in the increase in the noise background and polarization parameter (i.e. the ratio between the amplitude/power of the vertical component and that one of the horizontal component, in the changing characteristics of the slope of the power spectrum and fractal dimension, in the possible occurrence of short duration pulses. We conducted, with conventional techniques of data processing, a preliminary analysis of the magnetic field observations performed at L'Aquila during three months preceding the 6 April 2009 earthquake, focusing attention on the possible occurrence of features similar to those identified in previous events. Within the limits of this analysis, we do not find compelling evidence for any of the features which have been proposed as earthquake precursors: indeed, most of aspects of our observations (which, in some cases, appear consistent with previous findings might be interpreted in terms of the general magnetospheric conditions and/or of different sources.

  5. Pineapple juice as a negative oral contrast agent in magnetic resonance cholangiopancreatography: a preliminary evaluation.

    Science.gov (United States)

    Riordan, R D; Khonsari, M; Jeffries, J; Maskell, G F; Cook, P G

    2004-12-01

    The quality of magnetic resonance cholangiopancreatography (MRCP) images is frequently degraded by high signal from the gastrointestinal tract. The aim of this study is to evaluate pineapple juice (PJ) as an oral negative contrast agent in MRCP. Preliminary in vitro evaluation demonstrated that PJ shortened T(2) relaxation time and hence decreased T(2) signal intensity on a standard MRCP sequence to a similar degree to a commercially available negative contrast agent (ferumoxsil). Electrothermal atomic absorption spectrometry assay demonstrated a high manganese concentration in PJ of 2.76 mg dl(-1), which is likely to be responsible for its T(2) imaging properties. MRCP was subsequently performed in 10 healthy volunteers, before and at 15 min and 30 min following ingestion of 400 ml of PJ. Images were assessed blindly by two Consultant Radiologists using a standard grading technique based on contrast effect (degree of suppression of bowel signal), and image effect (diagnostic quality). There were statistically significant improvements in contrast and image effect between pre and post PJ images. There was particularly significant improvement in visualization of the pancreatic duct, but no significant difference between 15 min and 30 min post PJ images. Visualization of the ampulla, common bile duct, common hepatic and central intrahepatic ducts were also significantly improved at 15 min following PJ. Our results demonstrate that PJ, may be used as an alternative to commercially available negative oral contrast agent in MRCP.

  6. ITER Central Solenoid Module Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Smith, John [General Atomics, San Diego, CA (United States)

    2016-09-23

    The fabrication of the modules for the ITER Central Solenoid (CS) has started in a dedicated production facility located in Poway, California, USA. The necessary tools have been designed, built, installed, and tested in the facility to enable the start of production. The current schedule has first module fabrication completed in 2017, followed by testing and subsequent shipment to ITER. The Central Solenoid is a key component of the ITER tokamak providing the inductive voltage to initiate and sustain the plasma current and to position and shape the plasma. The design of the CS has been a collaborative effort between the US ITER Project Office (US ITER), the international ITER Organization (IO) and General Atomics (GA). GA’s responsibility includes: completing the fabrication design, developing and qualifying the fabrication processes and tools, and then completing the fabrication of the seven 110 tonne CS modules. The modules will be shipped separately to the ITER site, and then stacked and aligned in the Assembly Hall prior to insertion in the core of the ITER tokamak. A dedicated facility in Poway, California, USA has been established by GA to complete the fabrication of the seven modules. Infrastructure improvements included thick reinforced concrete floors, a diesel generator for backup power, along with, cranes for moving the tooling within the facility. The fabrication process for a single module requires approximately 22 months followed by five months of testing, which includes preliminary electrical testing followed by high current (48.5 kA) tests at 4.7K. The production of the seven modules is completed in a parallel fashion through ten process stations. The process stations have been designed and built with most stations having completed testing and qualification for carrying out the required fabrication processes. The final qualification step for each process station is achieved by the successful production of a prototype coil. Fabrication of the first

  7. Preliminary clinical application of an adaptive iterative statistical reconstruction algorithm inhead and neck computed tomography angiography with low tube voltage and a low concentration of contrast medium

    Institute of Scientific and Technical Information of China (English)

    Shan Hu; Wenzhen Zhu; Daoyu Hu; XiaoYan Meng; Jinhua Zhang; Weijia Wan; Li Zhou

    2015-01-01

    Objective To evaluate the feasibility of using a low concentration of contrast medium (Visipaque 270 mgI/mL), low tube voltage, and an advanced image reconstruction algorithm in head and neck computed tomography angiography (CTA). Methods Forty patients (22 men and 18 women; average age 48.7 ± 14.25 years; average body mass index 23.9 ± 3.7 kg/m2) undergoing CTA for suspected vascular diseases were randomly assigned into two groups. Group A (n = 20) was administered 370 mgI/mL contrast medium, and group B (n = 20) was administered 270 mgI/mL contrast medium. Both groups were administered at a rate of 4.8 mL/s and an injection volume of 0.8 mL/kg. Images of group A were obtained with 120 kVp and filtered back projection (FBP) reconstruction, whereas images of group B were obtained with 80 kVp and 80% adaptive iterative statistical reconstruction algorithm (ASiR). The CT values and standard deviations of intracranial arteries and image noise on the corona radiata were measured to calculate the contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). The beam-hardening artifacts (BHAs) around the skul base were calculated. Two readers evaluated the image quality with volume rendered images using scores from 1 to 5. The values between the two groups were statistical y compared. Results The mean CT value of the intracranial arteries in group B was significantly higher than that in group A (P < 0.001). The CNR and SNR values in group B were also statistical y higher than those in group A (P < 0.001). Image noise and BHAs were not significantly dif erent between the two groups. The image quality score of VR images of in group B was significantly higher than that in group A (P = 0.001). However, the quality scores of axial enhancement images in group B became significantly smal er than those in group A (P< 0.001). The CT dose index volume and dose-length product were decreased by 63.8% and 64%, respectively, in group B (P < 0.001 for both). Conclusion Visipaque

  8. Acquisition procedures, processing methodologies and preliminary results of magnetic and ROV data collected during the TOMO-ETNA experiment

    Directory of Open Access Journals (Sweden)

    Danilo Cavallaro

    2016-09-01

    Full Text Available The TOMO-ETNA experiment was devised for the investigation of the continental and oceanic crust beneath Mt. Etna volcano and northeastern Sicily up to the Aeolian Islands, through an active source study. In this experiment, a large amount of geophysical data was collected both inland and in the Ionian and Tyrrhenian Seas for identifying the major geological and structural features offshore Mt. Etna and NE Sicily. One of the oceanographic cruises organized within the TOMO-ETNA experiment was carried out on the hydrographic vessel “Galatea” by Italian Navy. During the cruise a detailed magnetic survey and a set of ROV (remotely operated vehicle dives were performed offshore Mt. Etna. The magnetic survey allowed the compilation of a preliminary magnetic map revealing a clear direct relationship between volcanic structures and high frequency magnetic anomalies. Significant positive magnetic anomalies were identified offshore the Timpa area and along the easternmost portion of the Riposto Ridge and correlated to a primitive volcanic edifice and to shallow volcanic bodies, respectively. On the whole, the magnetic anomaly map highlights a clear SW-NE decreasing trend, where high amplitude positive magnetic anomaly pattern of the SW sector passes, northeastwardly, to a main negative one. ROV dives permitted to directly explore the shallowest sectors of the Riposto Ridge and to collect several videos and seafloor samples, allowing us to identify some locally developed volcanic manifestations.

  9. [Low field intra-operative magnetic resonance imaging for brain tumour surgery: preliminary experience].

    Science.gov (United States)

    Roldán, Pedro; García, Sergio; González, Josep; Reyes, Luis Alberto; Torales, Jorge; Valero, Ricard; Oleaga, Laura; Enseñat, Joaquim

    Intra-operative magnetic resonance imaging (iMRI) is a recently introduced tool in the most advanced neurosurgical operating rooms worldwide. We present our preliminary experience in brain tumour surgery with low field PoleStar N30® intraoperative MRI since its introduction in 2013 in the Barcelona Clinic Hospital. A prospective non-randomised study was conducted on cases operated on using iMRI and intention of complete removal up to October 2015. A record was made of the data as regards surgical times, resection rates, histological diagnosis, hospital stay, and survival rates during follow-up. The study included 50 patients, with a mean age of 55 years (±13.7), a preoperative mean Karnofsky of 92 (being 81 post-operatively), and a mean follow-up of 10.5 months (±6.5). There were 26% re-operations due to recurrence. High-grade gliomas were reported in 56%, low-grade gliomas in 24%, and 20% "Other" tumours. Overall hospital stay was 10 days (±4.5). Depending on the histologiacl diagnosis, the "Others" group had a longer hospital stay. Overall, there were 52% complete removal, 18% of maximum removals, and 30% of partial removals. The overall survival rates during follow-up was 84%. iMRI is a safe and effective tool for brain tumour surgery. Its use allows an increase in resection rates, and minimises post-operative complications. Its implementation involves an increase in surgical time, which improves with the characteristic learning curve. More studies are needed to establish its role in the long-term survival of patients. Copyright © 2016 Sociedad Española de Neurocirugía. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Repetitive transcranial magnetic stimulation as an adjuvant method in the treatment of depression: Preliminary results

    Directory of Open Access Journals (Sweden)

    Jovičić Milica

    2014-01-01

    Full Text Available Introduction. Repetitive transcranial magnetic stimulation (rTMS is a method of brain stimulation which is increasingly used in both clinical practice and research. Up-to-date studies have pointed out a potential antidepressive effect of rTMS, but definitive superiority over placebo has not yet been confirmed. Objective. The aim of the study was to examine the effect of rTMS as an adjuvant treatment with antidepressants during 18 weeks of evaluation starting from the initial application of the protocol. Methods. Four patients with the diagnosis of moderate/severe major depression were included in the study. The protocol involved 2000 stimuli per day (rTMS frequency of 10 Hz, intensity of 120% motor threshold administered over the left dorsolateral prefrontal cortex (DLPFC for 15 days. Subjective and objective depressive symptoms were measured before the initiation of rTMS and repeatedly evaluated at week 3, 6, 12 and 18 from the beginning of the stimulation. Results. After completion of rTMS protocol two patients demonstrated a reduction of depressive symptoms that was sustained throughout the 15-week follow-up period. One patient showed a tendency of remission during the first 12 weeks of the study, but relapsed in week 18. One patient showed no significant symptom reduction at any point of follow-up. Conclusion. Preliminary findings suggest that rTMS has a good tolerability and can be efficient in accelerating the effect of antidepressants, particularly in individuals with shorter duration of depressive episodes and moderate symptom severity. [Projekat Ministarstva nauke Republike Srbije, br. III41029 i br. ON175090

  11. Magnetic resonance imaging features of the spinal cord in pediatric multiple sclerosis: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Verhey, Leonard H. [Hospital for Sick Children, Neuroscience and Mental Health, Toronto, ON (Canada); University of Toronto, Institute of Medical Science, Faculty of Medicine, Toronto, ON (Canada); Branson, Helen M.; Shroff, Manohar [Hospital for Sick Children, Department of Diagnostic Imaging (Neuroradiology), Toronto, ON (Canada); University of Toronto, Department of Medical Imaging, Toronto, ON (Canada); Makhija, Monica [Hospital for Sick Children, Neuroscience and Mental Health, Toronto, ON (Canada); Banwell, Brenda [Hospital for Sick Children, Neuroscience and Mental Health, Toronto, ON (Canada); University of Toronto, Institute of Medical Science, Faculty of Medicine, Toronto, ON (Canada); University of Toronto, Department of Pediatrics (Neurology), Toronto, ON (Canada)

    2010-12-15

    Spinal cord lesions in adults with multiple sclerosis (MS) are thought to contribute to disability. The magnetic resonance imaging (MRI) appearance and clinical correlates of spinal cord lesions in children with MS have not been reported. T1-weighted pre- and post-gadolinium and T2-weighted TSE/FSE spine MR images of 36 children (age, 14.3 {+-} 3.3) with relapsing-remitting MS (annualized relapse rate, 0.7; disease duration, 7.5 {+-} 3.3 years) were analyzed for total lesion count, lesion location and length, intramedullary extent, and gadolinium enhancement. Clinical, demographic, laboratory, and MRI data were correlated. Lesions preferentially involved the cervical region, were predominantly focal, and involved only a portion of the transverse cord diameter. However, ten of 36 patients demonstrated longitudinally extensive lesions. Children with the highest clinical relapse rate also tended to have more spinal cord lesions and were more likely to accrue new lesions on serial spinal scans. These preliminary data suggest that MS lesions of the spinal cord in children are radiographically similar to that of adult-onset MS - supporting a common biology of pediatric- and adult-onset disease. However, children with relapsing-remitting MS can also develop longitudinally extensive lesions, suggesting that such lesions may be less specific for diseases such as neuromyelitis optica in pediatric patients. All patients recovered well from spinal cord attacks, and the presence of spinal cord lesions in the first few years of disease did not correlate with physical disability. Measures of spinal cord atrophy and longer periods of observation are required to determine the impact of spinal cord involvement in pediatric-onset MS. (orig.)

  12. A Preliminary Full Spectrum Magnetic Anomaly Database of the United States With Improved Long Wavelengths for Studying Continental Dynamics

    Science.gov (United States)

    Ravat, D.; Sabaka, T.; Elshayat, A.; Aref, A.; Elawadi, E.; Kucks, R.; Hill, P.; Phillips, J.; Finn, C.; Bouligand, C.; Blakely, R. J.

    2008-12-01

    Under an initiative started by Thomas G. Hildenbrand of the U. S. Geological Survey, we have improved the long-wavelength (50-2500 km) content of the regional magnetic anomaly compilation for the conterminous United States by utilizing a nearly homogeneous set of National Uranium Resource Evaluation (NURE) magnetic surveys flown from 1975 to 1981. The surveys were flown in quadrangles of 2° of longitude by 1° of latitude with E-W flight-lines spaced 4.8 to 9.6 km, N-S tie-lines variably spaced, and a nominal terrain clearance of 122 m. Many of the surveys used base-station magnetometers to remove external field variations. NURE surveys were originally processed with IGRF core-field models, which left behind non- uniform residual trends in the data and discontinuities at survey boundaries. In this study, in place of the IGRF/DGRF, we used a spatially and temporally continuous model of the magnetic field known as the Comprehensive Model (CM), which allowed us to avoid discontinuities at survey boundaries. The CM simultaneously models the core magnetic field and long-wavelength ionospheric and magnetospheric fields, along with their induced components in the earth. Because of the availability of base-stations for removing external fields, we removed only the core-derived geomagnetic field based on CM4 (spherical harmonic degree 13) for our compilation. The NURE data have short-wavelength (less than 30 km) noise due to cultural sources, base-station offsets, and residual external field effects. It is possible to reduce and even remove these defects by identifying and editing them and by applying leveling and micro-leveling. There are also many high resolution individual surveys over the U.S. which could be incorporated into the improved NURE database; however, this could take a few years. Therefore, we have created a preliminary full spectrum magnetic anomaly database by combining short-wavelength magnetic anomalies from the North American Magnetic Anomaly Map (NAMAM

  13. Visualization of periventricular collaterals in moyamoya disease with flow-sensitive black-blood magnetic resonance angiography: preliminary experience.

    Science.gov (United States)

    Funaki, Takeshi; Fushimi, Yasutaka; Takahashi, Jun C; Takagi, Yasushi; Araki, Yoshio; Yoshida, Kazumichi; Kikuchi, Takayuki; Miyamoto, Susumu

    2015-01-01

    Fragile abnormal collaterals in moyamoya disease, known as "moyamoya vessels," have rarely been defined. While flow-sensitive black-blood magnetic resonance angiography (FSBB-MRA) is a promising technique for visualizing perforating arteries, as of this writing no other reports exist regarding its application to moyamoya disease. Six adults with moyamoya disease underwent FSBB-MRA. It depicted abnormal collaterals as extended lenticulostriate, thalamic perforating, or choroidal arteries, which were all connected to the medullary or insular artery in the periventricular area and supplied the cortex. This preliminary case series illustrates the potential for FSBB-MRA to reveal abnormal moyamoya vessels, which could be reasonably defined as periventricular collaterals.

  14. Preliminary analysis of the MER magnetic properties experiment using a computational fluid dynamics model

    DEFF Research Database (Denmark)

    Kinch, K.M.; Merrison, J.P.; Gunnlaugsson, H.P.;

    2006-01-01

    Motivated by questions raised by the magnetic properties experiments on the NASA Mars Pathfinder and Mars Exploration Rover (MER) missions, we have studied in detail the capture of airborne magnetic dust by permanent magnets using a computational fluid dynamics (CFD) model supported by laboratory...

  15. Development of liquid metal type TBM technology for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Bong Guen; Kwak, J. G.; Kim, Y. (and others)

    2008-03-15

    The objectives of the ITER project for the construction and operation are to perform the test related to the neutronics, blanket module, tritium treatment technology, advanced plasma technology, and to test the heat extraction and tritium breeding in the test blanket for the fusion reactor. Other parties have been developing the Test Blanket Module (TBM) for testing in the ITER for these purposes. Through this project, we can secure the TBM design and related technology, which will be used as the core technology for the DEMO construction, our own fusion reactor development. In 1st year, the optimized design procedure was established with the existing tools, which have been used in nuclear reactor design, and the optimized HCML TBM design was obtained through iteration method according to the developed design procedure. He cooling system as a TBM auxiliary system was designed considering the final design of the KO HCML TBM such as coolant capacity and operation pressure. Layout for this system was prepared to be installed in the ITER TCWS vault. MHD effect of liquid Li breeder by magnetic flux in ITER such as much higher pressure drop was evaluated with CFD-ACE and it was concluded that the Li breeder should have a slow velocity to reduce this effect. Most results were arranged in the form of DDD including preliminary safety analysis report. In 2nd year, the optimized design procedure was complemented and updated. In performance analysis on thermal-hydraulic and thermo-mechanical one, full 3D meshes were generated and used in this analysis in order to obtain the more exact temperature, deformation, and stress solution. For liquid Li breeder system, design parameters were induced before the detailed design of the system and were used in the design of the liquid Li test loop. LOCA analysis, activation analysis in LOCA, EM analysis were performed as a preliminary safety analysis. In order to develop the manufacturing technology, Be+FMS and FMS to FMS joining conditions

  16. Design and preliminary test results of the 40 MW power supply at the National High Magnetic Field Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Boenig, H.J. [Los Alamos National Lab., NM (United States); Bogdan, F.; Morris, G.C. [ABB Drives Inc., New Berlin, WI (United States); Ferner, J.A.; Schneider-Muntau, H.J. [National High Magnetic Field Lab., Tallahassee, FL (United States); Rumrill, R.H.; Rumrill, R.S. [Alpha Scientific Electronics Inc., Hayward, CA (United States)

    1993-11-01

    Four highly stabilized, steady-state, 10 MW power supplies have been installed at the National High Magnetic Field Laboratory in Tallahassee, FL. Each supply consists of a 12.5 kV vacuum circuit breaker, two three-winding, step-down transformers, a 24-pulse rectifier with interphase reactors and freewheeling diodes, and a passive and an active filter. Two different transformer tap settings allow dc supply output voltages of 400 and 500 V. The rated current of a supply is 17 kA and each supply has a one hour overload capability of 20 kA. The power supply output bus system, including a reversing switch at the input and 2 {times} 16 disconnect switches at the output, connects each supply to 16 different magnet cells. The design of the power supply is described and preliminary test results with a supply feeding a 10 MW resistive load are presented.

  17. Preliminary experimental investigation of an X-band Cerenkov-type high power microwave oscillator without guiding magnetic field

    Science.gov (United States)

    Guo, Liming; Shu, Ting; Li, Zhiqiang; Ju, Jinchuan; Fang, Xiaoting

    2017-02-01

    Among high power microwave (HPM) generators without guiding magnetic field, Cerenkov-type oscillator is expected to achieve a relatively high efficiency, which has already been realized in X-band in our previous simulation work. This paper presents the preliminary experimental investigations into an X-band Cerenkov-type HPM oscillator without guiding magnetic field. Based on the previous simulation structure, some modifications regarding diode structure were made. Different cathode structures and materials were tested in the experiments. By using a ring-shaped graphite cathode, microwave of about one hundred megawatt level was generated with a pure center frequency of 9.14 GHz, and an efficiency of about 1.3%. As analyzed in the paper, some practical issues reduce the efficiency in experiments, such as real features of the electron beam, probable breakdown regions on the cathode surface which can damage the diode, and so forth.

  18. Structural analysis of the ITER Vacuum Vessel regarding 2012 ITER Project-Level Loads

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.-M., E-mail: jean-marc.martinez@live.fr [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Jun, C.H.; Portafaix, C.; Choi, C.-H.; Ioki, K.; Sannazzaro, G.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Cambazar, M.; Corti, Ph.; Pinori, K.; Sfarni, S.; Tailhardat, O. [Assystem EOS, 117 rue Jacquard, L' Atrium, 84120 Pertuis (France); Borrelly, S. [Sogeti High Tech, RE2, 180 rue René Descartes, Le Millenium – Bat C, 13857 Aix en Provence (France); Albin, V.; Pelletier, N. [SOM Calcul – Groupe ORTEC, 121 ancien Chemin de Cassis – Immeuble Grand Pré, 13009 Marseille (France)

    2014-10-15

    Highlights: • ITER Vacuum Vessel is a part of the first barrier to confine the plasma. • ITER Vacuum Vessel as Nuclear Pressure Equipment (NPE) necessitates a third party organization authorized by the French nuclear regulator to assure design, fabrication, conformance testing and quality assurance, i.e. Agreed Notified Body (ANB). • A revision of the ITER Project-Level Load Specification was implemented in April 2012. • ITER Vacuum Vessel Loads (seismic, pressure, thermal and electromagnetic loads) were summarized. • ITER Vacuum Vessel Structural Margins with regards to RCC-MR code were summarized. - Abstract: A revision of the ITER Project-Level Load Specification (to be used for all systems of the ITER machine) was implemented in April 2012. This revision supports ITER's licensing by accommodating requests from the French regulator to maintain consistency with the plasma physics database and our present understanding of plasma transients and electro-magnetic (EM) loads, to investigate the possibility of removing unnecessary conservatism in the load requirements and to review the list and definition of incidental cases. The purpose of this paper is to present the impact of this 2012 revision of the ITER Project-Level Load Specification (LS) on the ITER Vacuum Vessel (VV) loads and the main structural margins required by the applicable French code, RCC-MR.

  19. Gas enhanced magnetic resonance angiography of the cerebrum using carbon dioxide and oxygen - preliminary results

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Hansen, Kristoffer Lindskov; Ohlhues, Anders

    and the meninges may obscure the signal from the arteries of interest. It is known that oxygen enhances the T1-weighted signal and that carbon dioxide increases the arterial blood flow. This paper presents preliminary results of gas enhanced MRA using combinations of atmospheric air, O2 and CO2. Subjects...... as a response to the added CO2 (gas II). Free oxygen (gas III) enhanced the MRA blood signal but invoked a slight decrease in the volume flow. Discussion/conclusion Inhaling gas mixture during MRA examination containing CO2 and O2 increased the cerebral MRA signal. These preliminary results indicate...

  20. Burn Control of Magnetically Confined Fusion Plasma 2. Burn Control in Tokamak Fusion Reactors 2.3 Burn Control in ITER

    Science.gov (United States)

    Fujisawa, Noboru

    The issue of burn control in FDR-ITER, the design of which was completed in 1998, is introduced, Controllability was studied based on the ID transport code, PRETOR, during the burn phase with self-ignition, as well as during start-up and shut-down. The results of the present study have helped us to identify the importance of controlling the fuel supply, impurity injection, and heating power to maintain fusion power and power to the divertor.

  1. Correlation Between Magnetic Parameters and Chemical Composition of Lake Sediments from Northern Bohemia Preliminary Study

    NARCIS (Netherlands)

    Petrovsky, E.; Kapicka, A.; Zapletal, K.; Sebestova, E.; Spanila, T.; Dekkers, M.J.; Rochette, P.

    1998-01-01

    Recently, magnetic measurements have been used m outline areas with increased loading of toxic metals due to industrial activity. It is supposed that magnetic minerals, which are easily detectable, can cant toxic metals of anthropic origin. However, physical background of this relationship is

  2. New Magnetic Anomaly Map of the East Asia with Some Preliminary Tectonic Interpretations

    Directory of Open Access Journals (Sweden)

    Wen-Bin Doo

    2015-01-01

    Full Text Available Magnetic data provides basic information for geological and geophysical interpretation. In this study we compile recently collected (57 cruises survey and old (published and open access magnetic data. This compilation includes land, marine and aeromagnetic data acquired in the East Asia region. The newly acquired magnetic data are mainly concentrated mainly in the South China Sea (SCS (especially in the northern continental shelf, the northwestern part of the West Philippine Basin (WPB, and the East China Sea. The updated magnetic dataset is gridded with a spacing of one arc-minute. The new magnetic map provides new insights into the tectonic setting of East Asia. Analysis of the compiled data reveals several regional anomaly patterns: (1 the NE-SW trending high positive magnetic anomaly zone extending from southwest Taiwan to the area about 114.5°E114.5°E and 22°N22°N is pronounced; but it is less continuous southwest of the Penghu islands. In addition, the orientation of this high linear magnetic zone changes slightly in 118.5°E,118.5°E, 22.5°N22.5°N from N60°EN60°E - N50°E.N50°E. (2 Between the Gagua Ridge (GR and the Luzon-Okinawa Fracture Zone (LOFZ the marine magnetic stripes of the WPB exhibit a NW-SE orientation. This suggests that the seafloor spreading could be related to the first stage of the WPB east of the LOFZ. (3 The Urdaneta and Amami plateaus are associated with high magnetization zones. These high magnetization zones extend northwestward and are subducting beneath the Ryukyu Trench.

  3. Approximate Modified Policy Iteration

    CERN Document Server

    Scherrer, Bruno; Ghavamzadeh, Mohammad; Geist, Matthieu

    2012-01-01

    Modified policy iteration (MPI) is a dynamic programming (DP) algorithm that contains the two celebrated policy and value iteration methods. Despite its generality, MPI has not been thoroughly studied, especially its approximation form which is used when the state and/or action spaces are large or infinite. In this paper, we propose three approximate MPI (AMPI) algorithms that are extensions of the well-known approximate DP algorithms: fitted-value iteration, fitted-Q iteration, and classification-based policy iteration. We provide an error propagation analysis for AMPI that unifies those for approximate policy and value iteration. We also provide a finite-sample analysis for the classification-based implementation of AMPI (CBMPI), which is more general (and somehow contains) than the analysis of the other presented AMPI algorithms. An interesting observation is that the MPI's parameter allows us to control the balance of errors (in value function approximation and in estimating the greedy policy) in the fina...

  4. Preliminary study of HTS magnet using 2G wires for maglev train

    Science.gov (United States)

    Ogata, Masafumi; Miyazaki, Yoshiki; Hasegawa, Hitoshi; Sasakawa, Takashi; Nagashima, Ken

    2010-06-01

    There are several advantages by applying a high temperature superconducting wire to an on-board superconducting magnet for the maglev train. At first, an increase of thermal capacity of superconducting coils contributes a stability of the superconducting state of the coils. In addition, a reliability of superconducting magnet improves by simplification of the magnet structure. And the weight of the superconducting magnet and the energy consumption of the on-board cryocooler will decrease. Therefore, we examined the possibility on application of the 2G wire with a high critical current density in a high magnetic field. We performed numerical analysis regarding the weight of a superconducting magnet and the energy consumption of an on-board cryocooler in consideration of the characteristics of the 2G wire. Furthermore, we have carried out the Ic measurement for the commercial 2G wires under various experimental conditions such as temperature, magnetic field strength and angle. We also performed the trial manufacture and evaluation of Ic characteristics for the small race track-shaped superconducting coil.

  5. Preliminary study of HTS magnet using 2G wires for maglev train

    Energy Technology Data Exchange (ETDEWEB)

    Ogata, Masafumi; Miyazaki, Yoshiki; Hasegawa, Hitoshi; Sasakawa, Takashi; Nagashima, Ken, E-mail: ogata@rtri.or.j [Railway Technical Research Institute, Hikari-cho 2-8-38, Kokubunji-shi, Tokyo (Japan)

    2010-06-01

    There are several advantages by applying a high temperature superconducting wire to an on-board superconducting magnet for the maglev train. At first, an increase of thermal capacity of superconducting coils contributes a stability of the superconducting state of the coils. In addition, a reliability of superconducting magnet improves by simplification of the magnet structure. And the weight of the superconducting magnet and the energy consumption of the on-board cryocooler will decrease. Therefore, we examined the possibility on application of the 2G wire with a high critical current density in a high magnetic field. We performed numerical analysis regarding the weight of a superconducting magnet and the energy consumption of an on-board cryocooler in consideration of the characteristics of the 2G wire. Furthermore, we have carried out the I{sub c} measurement for the commercial 2G wires under various experimental conditions such as temperature, magnetic field strength and angle. We also performed the trial manufacture and evaluation of I{sub c} characteristics for the small race track-shaped superconducting coil.

  6. Applied iterative methods

    CERN Document Server

    Hageman, Louis A

    2004-01-01

    This graduate-level text examines the practical use of iterative methods in solving large, sparse systems of linear algebraic equations and in resolving multidimensional boundary-value problems. Assuming minimal mathematical background, it profiles the relative merits of several general iterative procedures. Topics include polynomial acceleration of basic iterative methods, Chebyshev and conjugate gradient acceleration procedures applicable to partitioning the linear system into a "red/black" block form, adaptive computational algorithms for the successive overrelaxation (SOR) method, and comp

  7. Preliminary investigations of magnetic modulated nanoparticles for microwave breast cancer detection

    Directory of Open Access Journals (Sweden)

    Ley S.

    2015-09-01

    Full Text Available This paper investigates the potential of magnetic modulated iron oxide nanoparticles in terms of a contrast enhancement for Ultra-wideband (UWB breast imaging. The work is motivated by the low dielectric contrast between tumor and normal glandular/fibroconnective tissue. The influence of an external polarizing magnetic field on pure and coated magnetite nanoparticles is investigated in this contribution. Measurements were conducted using M-sequence UWB technology and an oil-gelatin phantom. It is shown that a coating, which is necessary for clinical use, results in a lower signal response, and thus leads to a lower detectability of magnetic modulated nanoparticles.

  8. ITER test programme

    Science.gov (United States)

    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.

  9. Marine magnetic studies in the northern Bay of Bengal, preliminary results

    Digital Repository Service at National Institute of Oceanography (India)

    Ramana, M.V.; Subrahmanyam, V.; Krishna, K.S.; Chaubey, A.K.; Sarma, K.V.L.N.S.; Murty, G.P.S.; Murty, P.S.N.; Rao, D.G.; Mittal, G.S.; Drolia, R.K.

    The bathymetric and total magnetic intensity data collected along six E-W tracks were analysed and presented as stacked anomaly profiles. A first order basement configuration model was generated across the Bay of Bengal. The model studies indicate...

  10. Preliminary Results on Magnetic Mineralogy and Elemental Composition of Meteorites from Geological Museum of Kazan University

    Science.gov (United States)

    Kuzina, D. M.; Nurgaliev, D. K.; Gareev, B. I.; Batalin, G. A.; Silantev, V. V.

    2016-08-01

    Thermomagnetic analysis (magnetic mineralogy) and Micro X-ray Fluorescence analysis (mapping) were made for collection of meteorites. As a result we have elements distribution on surface of meteorites and Fe-Ni presence in meteorites.

  11. Confinement margins for ignition and driven operation in Iter Eda ID

    Energy Technology Data Exchange (ETDEWEB)

    Johner, J.

    1995-09-01

    Preliminary calculations for ITER EDA ID have been performed using the 1/2D thermal equilibrium code HELIOS. It is found that: - The maximum ignition margin for ITER ID (29%) is 6% less than for ITER OD (35%) and 5% less than for ITER CDA (34%). - Decreasing the ration {tau}{sup *}{sub He}/{tau}{sub E} from the nominal value 10 to a value of 5 gives a 12% gain in the maximum ignition margin. Increasing the ration from 10 to 15 causes a 22% loss in the margin. Furthermore, ignited equilibria non longer exist for {tau}{sup *}{sub He}/{tau}{sub E} {>=} 17.6. - Operation in driven mode with 50 MW of external power increases the confinement capability by 13%. With 100 MW, the improvement is 24%. - Lowering the fusion power from 1500 to 1000 MW slightly improves the maximum ignition margin (+5%) and allows operation below the Greenwald density limit. - A 10% reduction of the toroidal magnetic field with a correlative diminution of the plasma current for constant safety factor operation, causes a dramatic reduction (-18%) of the maximum ignition margin. - A fraction of neon of 0.68% would completely suppress the ignition margin. Furthermore, ignited equilibria, with the nominal fusion power and {tau}{sup *}{sub He}/{tau}{sub E}, no longer exist when the neon fraction exceeds 0.75%. (Author). 2 refs., 10 figs.

  12. Overview and status of ITER Cryostat manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, Anil K., E-mail: anil.bhardwaj@iter-india.org [ITER-India, Institute For Plasma Research, A-29, GIDC Electronics Estate, Sector-25, Gandhinagar 382016 (India); Gupta, Girish; Prajapati, Rajnikant; Joshi, Vaibhav; Patel, Mitul; Bhavsar, Jagrut; More, Vipul; Jindal, Mukesh; Bhattacharya, Avik; Jogi, Gourav; Palaliya, Amit; Jha, Saroj; Pandey, Manish; Shukla, Dileep [ITER-India, Institute For Plasma Research, A-29, GIDC Electronics Estate, Sector-25, Gandhinagar 382016 (India); Iyer, Ganesh; Jadhav, Pandurang; Goyal, Dipesh; Desai, Anish [Larsen & Toubro Limited, Heavy Engineering, Hazira Manufacturing Complex, Gujarat (India); Sekachev, I.; Vitupier, Guillaume [ITER Organization, Route de Vinon sur Verdon – CS 90046, 13067 Saint Paul Lez Durance Cedex (France); and others

    2016-11-01

    Highlights: • Manufacturing status of one of the largest and the heaviest fully welded stainless steel vacuum chambers in the world (ITER Cryostat). • Overview of manufacturing stages and its segmentation. • Overview of manufacturing procedures and assembly and installation. - Abstract: One of ITER-India's commitments to the ITER Organization is procurement of the ITER Cryostat. It is a large vacuum vessel (∼29 m dia. and ∼29 m height), which is made up of 304/304 L dual marked stainless steel and has a total mass over 3500 t. The thickness of the vessel wall varies from 50 mm to 190 mm. It is one of the largest and the heaviest fully welded stainless steel vacuum chambers in the world which provides vacuum thermal insulation for the superconducting magnets operating at 4.5 K and for the thermal shield operating at 80 K. It also mechanically supports the magnet system along with the vacuum vessel (VV). The cryostat is designed and constructed according to ASME Section-VIII Division-2 with additional ITER Vacuum Handbook requirements and it is classified as protection important component (PIC-2). Manufacturing of cryostat segments is ongoing in India; sub-assembly of four major sections of the cryostat from the segments will be done at the ITER site in a temporary workshop building and the final assembly will be done in the pit of the tokamak building, the final location. The cryostat manufacturing contract has been awarded to Larsen and Toubro Limited in August 2012 after completion of design [4] and signing of Procurement Arrangement [1] with ITER Organization. Manufacturing of the cryostat was started in January 2014 after approval of the manufacturing drawings and procedures. The temporary workshop of 44 m × 110 m × 26 m in height has been completed in November 2014 at the ITER site with a 200 t crane installed. This paper gives an overview and the status of the cryostat manufacturing.

  13. The OMERACT psoriatic arthritis magnetic resonance imaging scoring system (PsAMRIS): definitions of key pathologies, suggested MRI sequences, and preliminary scoring system for PsA Hands

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; McQueen, Fiona; Wiell, Charlotte

    2009-01-01

    This article describes a preliminary OMERACT psoriatic arthritis magnetic resonance image scoring system (PsAMRIS) for evaluation of inflammatory and destructive changes in PsA hands, which was developed by the international OMERACT MRI in inflammatory arthritis group. MRI definitions of important...

  14. Iteration, Not Induction

    Science.gov (United States)

    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…

  15. Preliminary gravity and magnetic models across Midway Valley and Yucca Wash, Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Ponce, D.A.; Langenheim, V.E.

    1994-12-31

    Detailed gravity and ground magnetic data collected along ten traverses across Midway Valley and Yucca Wash on the eastern flank of Yucca Mountain in southwest Nevada are interpreted. These data were collected as part of an effort to evaluate faulting in the vicinity of proposed surface facilities for a potential nuclear waste repository at Yucca Mountain. Geophysical data show that Midway Valley is bounded by large gravity and magnetic anomalies associated with the Bow Ridge and Paintbrush Canyon faults, on the west side of Exile Hill and on the west flank of Fran Ridge, respectively. In addition, Midway Valley itself is characterized by a number of small-amplitude anomalies that probably reflect small-scale faulting beneath Midway Valley. Gravity and magnetic data across the northwest trending Yucca Wash and the inferred Yucca Wash fault indicate no major vertical offsets greater than 100 m using a density contrast of 0.2 to 0.3 g/cm{sup 3} along the proposed Yucca Wash fault. In addition, a broad magnetic high coincides with the approximate location of the hydrologic gradient and probably reflects moderately magnetic Topopah Spring Tuff or lavas in the Calico Hills Formation.

  16. ITER at Cadarache; ITER a Cadarache

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-06-15

    This public information document presents the ITER project (International Thermonuclear Experimental Reactor), the definition of the fusion, the international cooperation and the advantages of the project. It presents also the site of Cadarache, an appropriate scientifical and economical environment. The last part of the documentation recalls the historical aspect of the project and the today mobilization of all partners. (A.L.B.)

  17. Maturation of limbic regions in Asperger syndrome: a preliminary study using proton magnetic resonance spectroscopy and structural magnetic resonance imaging.

    Science.gov (United States)

    O'Brien, Finian M; Page, Lisa; O'Gorman, Ruth L; Bolton, Patrick; Sharma, Ajay; Baird, Gillian; Daly, Eileen; Hallahan, Brian; Conroy, Ronán M; Foy, Catherine; Curran, Sarah; Robertson, Dene; Murphy, Kieran C; Murphy, Declan G M

    2010-11-30

    People with autistic spectrum disorders (ASD, including Asperger syndrome) may have developmental abnormalities in the amygdala-hippocampal complex (AHC). However, in vivo, age-related comparisons of both volume and neuronal integrity of the AHC have not yet been carried out in people with Asperger syndrome (AS) versus controls. We compared structure and metabolic activity of the right AHC of 22 individuals with AS and 22 healthy controls aged 10-50 years and examined the effects of age between groups. We used structural magnetic resonance imaging (sMRI) to measure the volume of the AHC, and magnetic resonance spectroscopy ((1)H-MRS) to measure concentrations of N-acetyl aspartate (NAA), creatine+phosphocreatine (Cr+PCr), myo-inositol (mI) and choline (Cho). The bulk volume of the amygdala and the hippocampus did not differ significantly between groups, but there was a significant difference in the effect of age on the hippocampus in controls. Compared with controls, young (but not older) people with AS had a significantly higher AHC concentration of NAA and a significantly higher NAA/Cr ratio. People with AS, but not controls, had a significant age-related reduction in NAA and the NAA/Cr ratio. Also, in people with AS, but not controls, there was a significant relationship between concentrations of choline and age so that choline concentrations reduced with age. We therefore suggest that people with AS have significant differences in neuronal and lipid membrane integrity and maturation of the AHC.

  18. Risk mitigation strategy for the ITER electron cyclotron upper port launcher

    OpenAIRE

    Goede, A. P. H.; Bongers, W. A.; Elzendoorn, B. S. Q.; Graswinckel, M. F.; M.R. de Baar

    2010-01-01

    A basic requirement for ITER equipment to meet is a high level of reliability, because ITER operation time is precious and radioactive operation leaves limited scope for repair. In order to reduce the risk of failure during ITER operation an effective risk mitigation strategy is necessary. This paper presents such strategy for the ITER electron cyclotron upper port launcher (ECUPL). A preliminary ECUPL risk analysis identifies possible failure modes. A probabilistic risk assessment quantifies...

  19. Another year of successful collaboration between ITER and CERN

    CERN Multimedia

    Lucio Rossi and Frederick Bordry

    The 4th meeting of the Steering Committee of the CERN-ITER Collaboration Agreement was held on 19 November at CERN. It marked the end of a second year of successful collaboration between ITER and CERN on superconducting magnets and associated technologies and the establishment of CERN as the ITER “reference laboratory” for superconducting strand testing for the next five years.   From left to right: Luca Bottura, Head of the CERN Superconductor and Devices Section, Neil Mitchell, Head of the ITER Magnet Division, Frederick Bordry, Head of the CERN Technology Department, Arnaud Devred, Head of the ITER Superconductor Systems and Auxiliaries Section, and Lucio Rossi, Head of the CERN Magnet, Superconductors and Cryostats Group, standing in front of a sample holder used for critical current measurements of Nb3Sn strands in the Superconductor Laboratory (bldg 163) at CERN. The implementation agreement for 2009 encompassed a wide range of topics ranging from expertise in stainless ...

  20. The administration of psilocybin to healthy, hallucinogen-experienced volunteers in a mock-functional magnetic resonance imaging environment: a preliminary investigation of tolerability.

    Science.gov (United States)

    Carhart-Harris, Robin L; Williams, Tim M; Sessa, Ben; Tyacke, Robin J; Rich, Ann S; Feilding, Amanda; Nutt, David J

    2011-11-01

    This study sought to assess the tolerability of intravenously administered psilocybin in healthy, hallucinogen-experienced volunteers in a mock-magnetic resonance imaging environment as a preliminary stage to a controlled investigation using functional magnetic resonance imaging to explore the effects of psilocybin on cerebral blood flow and activity. The present pilot study demonstrated that up to 2 mg of psilocybin delivered as a slow intravenous injection produces short-lived but typical drug effects that are psychologically and physiologically well tolerated. With appropriate care, this study supports the viability of functional magnetic resonance imaging work with psilocybin.

  1. White Matter Integrity in Asperger Syndrome: A Preliminary Diffusion Tensor Magnetic Resonance Imaging Study in Adults

    NARCIS (Netherlands)

    O.J.N. Bloemen; Q. Deeley; F. Sundram; E.M. Daly; G.J. Barker; D.K. Jones; T.A.M.J. van Amelsvoort; N. Schmitz; D. Robertson; K.C. Murphy; D.G.M. Murphy

    2010-01-01

    Background: Autistic Spectrum Disorder (ASD), including Asperger syndrome and autism, is a highly genetic neurodevelopmental disorder. There is a consensus that ASD has a biological basis, and it has been proposed that it is a "connectivity" disorder. Diffusion Tensor Magnetic Resonance Imaging (DT-

  2. Preliminary measurements of the edge magnetic field pitch from 2-D Doppler backscattering in MAST and NSTX-U (invited)

    Science.gov (United States)

    Vann, R. G. L.; Brunner, K. J.; Ellis, R.; Taylor, G.; Thomas, D. A.

    2016-11-01

    The Synthetic Aperture Microwave Imaging (SAMI) system is a novel diagnostic consisting of an array of 8 independently phased antennas. At any one time, SAMI operates at one of the 16 frequencies in the range 10-34.5 GHz. The imaging beam is steered in software post-shot to create a picture of the entire emission surface. In SAMI's active probing mode of operation, the plasma edge is illuminated with a monochromatic source and SAMI reconstructs an image of the Doppler back-scattered (DBS) signal. By assuming that density fluctuations are extended along magnetic field lines, and knowing that the strongest back-scattered signals are directed perpendicular to the density fluctuations, SAMI's 2-D DBS imaging capability can be used to measure the pitch of the edge magnetic field. In this paper, we present preliminary pitch angle measurements obtained by SAMI on the Mega Amp Spherical Tokamak (MAST) at Culham Centre for Fusion Energy and on the National Spherical Torus Experiment Upgrade at Princeton Plasma Physics Laboratory. The results demonstrate encouraging agreement between SAMI and other independent measurements.

  3. Seismic heating signatures in the Japan Trench subduction plate-boundary fault zone: evidence from a preliminary rock magnetic `geothermometer'

    Science.gov (United States)

    Yang, Tao; Dekkers, Mark J.; Zhang, Bo

    2016-04-01

    Frictional heating during earthquake rupture reveals important information on earthquake mechanisms and energy dissipation. The amount of annealing varies widely and is, as yet, poorly constrained. Here we use magnetic susceptibility versus temperature measurements during cycling to increasingly elevated temperatures to constrain the maximum temperature a slip zone has experienced. The case study comprises sheared clay cored from the Japan Trench subduction plate-boundary fault zone (décollement), which accommodated the large slip of the 2011 Mw 9.0 Tohoku-oki earthquake. The décollement was cored during the Integrated Ocean Drilling Program (IODP) Expedition 343, the Japan Trench Fast Drilling Project (JFAST). Heating signatures with estimated maximum temperatures ranging from ˜300 to over 500 °C are determined close to the multiple slip surfaces within the décollement. Since it is impossible to tie a specific slip surface to a certain earthquake, thermal evidence for the cumulative effect of several earthquakes is unveiled. This as yet preliminary rock magnetic `geothermometer' would be a useful tool to detect seismic heating along faults that experienced medium temperature rise, a range which is difficult to assess with other approaches.

  4. Preliminary experiments about the measure of the magnetic properties of a material by means of TDR probes

    Science.gov (United States)

    Persico, Raffaele

    2016-04-01

    In this contribution, the possibility of measuring possible magnetic properties of materials by means of a TDR probe is studied. A transmission line model is adopted and data in time and frequency domain are exploited together. Simulation results are shown, at the moment based on a bifilar line model. Magnetic properties of materials can be of interest for several applications. In particular, the presence of magnetic features in the soil or in any substance, might be associated to some contaminant (presumably containing some metallic element as iron, nickel or chromium [1]). This kind of pollution might occur close to some farms, especially regarding the dying of dresses, the production of some medicines, the tanning of leather issues. Moreover, modern agriculture puts in the soil several fertilizing substances, and there is a debate about the quantity of heavy metals spread in the terrain by these activities [2]. Still, some depuration-mud can be affected by an excessive presence of metallic elements, because of the presence of batteries, skins, varnishes, cosmetics, and so on [2]. Moreover, it is thought that the soil on the planet Mars might show magnetic properties [3]. Finally, in GPR prospecting, possible magnetic characteristics of the soil or of the targets might be of interest too [4], but they cannot be retrieved by means of only GPR data [5]. In the present paper, the results of a preliminary study are exposed with regard to the possibility to measure the magnetic properties of a material by mean of a TDR probe [6-7]. In particular a TDR probe is essentially a transmission line (a bifilar model will be exploited in this work) open at the end, form which most of the impinging energy (ideally the whole of thi energy in a lossless medium) is back reflected. In particular, this allows a customary measure of the propagation velocity in the medium if an impulsive signal is generated. In fact, the return time along a path of known length is measured. The

  5. Materials Characterization of Feraheme/Ferumoxytol and Preliminary Evaluation of Its Potential for Magnetic Fluid Hyperthermia

    Directory of Open Access Journals (Sweden)

    Jon Dobson

    2013-08-01

    Full Text Available Feraheme, is a recently FDA-cleared superparamagnetic iron oxide nanoparticle (SPION-based MRI contrast agent that is also employed in the treatment of iron deficiency anemia. Feraheme nanoparticles have a hydrodynamic diameter of 30 nm and consist of iron oxide crystallites complexed with a low molecular weight, semi-synthetic carbohydrate. These features are attractive for other potential biomedical applications such as magnetic fluid hyperthermia (MFH, since the carboxylated polymer coating affords functionalization of the particle surface and the size allows for accumulation in highly vascularized tumors via the enhanced permeability and retention effect. This work presents morphological and magnetic characterization of Feraheme by transmission electron microscopy (TEM, Energy dispersive X-ray spectroscopy (EDX, and superconducting quantum interference device (SQUID magnetometry. Additionally, the results of an initial evaluation of the suitability of Feraheme for MFH applications are described, and the data indicate the particles possess promising properties for this application.

  6. Magnetic resonance imaging in the assessment of revascularization in Kienbock's disease. A preliminary report.

    Science.gov (United States)

    Viegas, S F; Amparo, E

    1989-12-01

    A 25-year-old man with stage II Kienbock's disease of his left lunate underwent an initial period of immobilization. He was subsequently treated by ulnar lengthening, with a good outcome. Magnetic resonance imaging (MRI) was utilized to demonstrate the lack of improvement with cast immobilization and the revascularization that followed surgical treatment. This new application of MRI in cases of avascular necrosis of the lunate may be helpful in the early identification of revascularization.

  7. Magnetization transfer imaging reveals geniculocalcarine and striate area degeneration in primary glaucoma: a preliminary study

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2016-09-01

    Full Text Available Background Glaucoma is a neurodegenerative disease that affects both the retina and central visual pathway. Magnetization transfer imaging (MTI is a sensitive magnetic resonance imaging (MRI technique that can detect degenerative changes in the brain. Purpose To investigate the geniculocalcarine (GCT and striate areas in primary glaucoma patients using region of interest (ROI analysis of magnetization transfer ratio (MTR. Material and Methods Twenty patients with primary glaucoma in both eyes were compared with 31 healthy control patients. All of the participants were examined on a 3.0 T scanner using a three-dimensional T1-weighted spoiled gradient recalled acquisition (SPGR with and without a MT saturation pulse. A two-sample t-test was used to evaluate the MTR difference between the groups. P < 0.05 was used to determine statistical significance. Results The MTR of the glaucoma group was lower than the healthy controls in both the bilateral GCT (t = 3.781, P = 0.001 and striate areas (t = 4.177, P = 0.000. Conclusion The MTR reductions in the bilateral GCT and striate areas suggest that there is GCT demyelination and striate area degeneration in primary glaucoma. These neurodegenerative effects may be induced as a direct effect of retrograde axonal degeneration along with the indirect effect of anterograde trans-synaptic degeneration.

  8. Approximate iterative algorithms

    CERN Document Server

    Almudevar, Anthony Louis

    2014-01-01

    Iterative algorithms often rely on approximate evaluation techniques, which may include statistical estimation, computer simulation or functional approximation. This volume presents methods for the study of approximate iterative algorithms, providing tools for the derivation of error bounds and convergence rates, and for the optimal design of such algorithms. Techniques of functional analysis are used to derive analytical relationships between approximation methods and convergence properties for general classes of algorithms. This work provides the necessary background in functional analysis a

  9. Novel aspects of plasma control in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, D.; Jackson, G.; Walker, M.; Welander, A. [General Atomics P.O. Box 85608, San Diego, California 92186-5608 (United States); Ambrosino, G.; Pironti, A. [CREATE/University of Naples Federico II, Napoli (Italy); Vries, P. de; Kim, S. H.; Snipes, J.; Winter, A.; Zabeo, L. [ITER Organization, St. Paul Lez durance Cedex (France); Felici, F. [Eindhoven University of Technology, Eindhoven (Netherlands); Kallenbach, A.; Raupp, G.; Treutterer, W. [Max-Planck Institut für Plasmaphysik, Garching (Germany); Kolemen, E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States); Lister, J.; Sauter, O. [Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland); Moreau, D. [CEA, IRFM, 13108 St. Paul-lez Durance (France); Schuster, E. [Lehigh University, Bethlehem, Pennsylvania (United States)

    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. Novel aspects of plasma control in ITER

    Science.gov (United States)

    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.

  11. Preliminary Modeling of Permanent Magnet Probe Flowmeter for Voltage Signal Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Uiju; Kim, Sung Joong [Hanyang Univ., Seoul (Korea, Republic of); Jeong, Ji Young; Kim, Tae Joon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    An experimental study on performance analysis of the flowmeter has been performed. The study shows that sodium flow rate is linearly proportional to the induced voltage signal from the flowmeter under the turbulent flow condition. The experimental results support its availability in the PDRC system. But, the flowmeter should be able to measure sodium flow at low Reynolds number as well. That is because the PDRC system uses sodium natural convection for its operation. Thus, calibration of the flowmeter should be done at very low sodium flow rates. However, Von Weissenfluh et al. showed that the relationship between flow rate and measured voltage signal from the flowmeter may become non-linear at very low flow rates. The nonlinearity restricts the utilization of level sensor which provide reference flow rate in the calibration experiment. The primary objective of this study is to predict the sodium flow rate range where the induced voltage signals are linearly proportional to flow rates by estimating the induced voltage signals against sodium flow rates for a wide range of flows numerically. A commercial code FLUENT is adopted for the analysis of flow field. And MAXWELL which is an electromagnetic analysis software using a finite volume method has been used to analyze the magnetic field generated by permanent magnet of the flowmeter. The induced voltage signals have been estimated by coupling the sodium flow field and the magnetic field using FLUENT MHD module. It is expected that the PMPF voltage signals are linearly proportional to flow rates range of 0.0059 to 1.96 lps. This suggests that simple calibration technique using the linearity between flow rate and the voltage signal can be adopted in calibration of the PMPF.

  12. Preliminary Study of the Feasibility of Inverse Problem Algorithms Used for Arc Magnetic Measurement Method

    Science.gov (United States)

    Wang, Qian; Li, Xingwen; Song, Haoyong; Rong, Mingzhe

    2010-04-01

    Non-contact magnetic measurement method is an effective way to study the air arc behavior experimentally One of the crucial techniques is to solve an inverse problem for the electromagnetic field. This study is devoted to investigating different algorithms for this kind of inverse problem preliminarily, including the preconditioned conjugate gradient method, penalty function method and genetic algorithm. The feasibility of each algorithm is analyzed. It is shown that the preconditioned conjugate gradient method is valid only for few arc segments, the estimation accuracy of the penalty function method is dependent on the initial conditions, and the convergence of genetic algorithm should be studied further for more segments in an arc current.

  13. Safety of high speed magnetic levitation transportation systems. Preliminary safety review of the transrapid maglev system

    Science.gov (United States)

    Dorer, R. M.; Hathaway, W. T.

    1990-11-01

    The safety of various magnetically levitated trains under development for possible implementation in the United States is of direct concern to the Federal Railroad Administration. Safety issues are addressed related to a specific maglev technology. The Transrapid maglev system was under development by the German Government over the last 10 to 15 years and was evolved into the current system with the TR-07 vehicle. A technically based safety review was under way over the last year by the U.S. Department of Transportation. The initial results of the review are presented to identify and assess potential maglev safety issues.

  14. Beyond ITER: Neutral beams for DEMO

    CERN Document Server

    McAdams, R

    2013-01-01

    In the development of magnetically confined fusion as an economically sustainable power source, ITER is currently under construction. Beyond ITER is the DEMO programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

  15. Treatment for Traumatic Brain Injury in Mice Using Transcranial Magnetic Stimulation: A Preliminary Study

    Science.gov (United States)

    Carr, Alexandria; Zenitsky, Gary; Crowther, Lawrence; Hadimani, Ravi; Anantharam, Vellareddy; Kanthasamy, Anumantha; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) is a non-invasive surgery-free tool used to stimulate the brain by time-varying magnetic fields. TMS is currently being investigated as a treatment for neurological disorders such as depression, Parkinson's disease and TBI. Before moving to human TMS/TBI trials, animal testing should be pursued to determine suitability and adverse effects. As an initial study, four healthy mice were treated with TMS at different power levels to determine short-term behavioral effects and set a control group baseline. The mouse's behavior was studied using the Rotorod test, which measures the animal's latency to fall off a rotating rod, and the Versamax test, which measures horizontal and vertical movement, and total distance traveled. The Rotorod test has shown for TMS power levels >=90% the mice begin to fall directly post-treatment. Similarly, the Versamax test has shown for power levels >=80% the mice are less mobile directly post-treatment. Versamax mobility was found to return to normal the day following treatment. These mice were housed in the facility for 4 months and the behavioral tests were repeated. Versamax results showed there was no significant variation in mobility indicating there are no long-term side effects of TMS treatment on the mice. This work was supported by the Barbara and James Palmer Endowment and the Carver Charitable Trust at the Department of Electrical and Computer Engineering, Iowa State University.

  16. Gas enhanced magnetic resonance angiography of the cerebrum using carbon dioxide and oxygen - preliminary results

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Hansen, Kristoffer Lindskov; Ohlhues, Anders

    compared. Results The TOF series showed an increase in MRA signal and vessel conspicuousness, when adding CO2 to air (gas I vs. gas II) and an additional increase was seen on MRA when adding O2 to CO2 (gas II vs. gas III). The increase in MRA signal was present on both volunteers. The volume flow increased...... and the meninges may obscure the signal from the arteries of interest. It is known that oxygen enhances the T1-weighted signal and that carbon dioxide increases the arterial blood flow. This paper presents preliminary results of gas enhanced MRA using combinations of atmospheric air, O2 and CO2. Subjects...... and Methods Two healthy volunteers were scanned during inhalation of three different gas mixtures: Gas I (air), Gas II (5% CO2, 21 % O2, 74 % N2), Gas III (5% CO2, 95% O2). For each gas mixture a time of flight (TOF) series on the cerebral arteries was performed. Following each TOF series an ECG-gated phase...

  17. Implications of Preliminary Gravity and Magnetic Surveys to the Understanding of the Bartlett Springs Fault Zone, Northern California Coast Ranges

    Science.gov (United States)

    Langenheim, V. E.; Jachens, R. C.; Morin, R. L.; McCabe, C. M.; Page, W. D.

    2007-12-01

    of this anomaly, caused by ultramafic rocks, coincides with the Bartlett Springs fault zone for nearly 15 km. Lake magnetic data indicate as many as three right-stepping strands of the Bartlett Springs fault zone within the gravity- defined pull-apart basin. Two pairs of magnetic anomalies appear to be dextrally offset along the fault, arguing for about 8-9 km of cumulative offset on the fault since the passage of the triple junction at about 3.5 Ma. This estimate is similar to proposed offsets of the Eel River (8.6-10.9 km) at Lake Pillsbury. The minimum long-term slip rate is thus 2.3-3.1 mm/yr, considerably slower than geodetic rates of 5-8 mm/yr. Seismicity forms a 5-km-wide diffuse zone along the Bartlett Springs fault zone in the Lake Pillsbury area, with fewer earthquakes about 5 km northwest of the lake and its associated magnetic anomaly. The McCreary Glade seismicity lineament, located between Potter Valley and Lake Pillsbury, has been attributed to a dike intrusion at depth or reactivation of an older structure. These earthquakes coincide with the northeast edge of a 100-km-long belt of aeromagnetic anomalies and thus appear to have reactivated an older basement feature. The coincidence of the Bartlett Springs fault zone and significant gravity gradients also argues that the much younger fault zone has reactivated older basement features. Our analysis shows that a modern, high-resolution aeromagnetic survey is needed to confirm these preliminary interpretations.

  18. Fictitious Reference Iterative Tuning-Based Two-Degrees-of-Freedom Method for Permanent Magnet Synchronous Motor Speed Control Using FPGA for a High-Frequency SiC MOSFET InverterMOSFET Inverter

    Directory of Open Access Journals (Sweden)

    Charles Ronald Harahap

    2016-11-01

    Full Text Available This paper proposes proportional-integral/proportional gain controller parameter tuning in a two-degrees-of-freedom (2DOF control system using the fictitious reference iterative tuning (FRIT method for permanent magnet synchronous motor (PMSM speed control using a field-programmable gate array (FPGA for a high-frequency SiC MOSFET (metal oxide semiconductor field-effect transistor inverter. The PI-P (proportional-integral/proportional controller parameters can be tuned using the FRIT method from one-shot experimental data without using a mathematical model of the plant. Particle swarm optimization is used for FRIT optimization. An inverter that uses a SiC MOSFET is presented to achieve high-frequency operation at up to100 kHz using a switching pulse-width modulation (PWM technique. As a result, a high-responsivity and high-stability PMSM (permanent magnet synchronous motor control system is achieved, where the speed response follows the ideal response characteristic for both the step response and the disturbance response. High-responsivity and optimal disturbance rejection can be achieved using the 2DOF control system. FPGA-based digital hardware control is used to maximize the switching frequency of the SiC MOSFET inverter. Finally, an experimental system is set up, and experimental results are presented to prove the viability of the proposed method.

  19. Palaeomagnetic, rock-magnetic and mineralogical investigations of metadolerites from Western Svalbard : A preliminary report

    Science.gov (United States)

    Michalski, Krzysztof; Nejbert, Krzysztof; Domańska-Siuda, Justyna; Manby, Geoffrey

    2014-05-01

    mA/m. The first AF/thermal demagnetizations have revealed a stable NRM structure. ChRM (Characteristic Remanent Magnetisation) components can be extracted precisely from Zijderveld diagrams (precision parameter - ASD max. 10º). The following magnetic procedures have been applied to identify the ferromagnetic carriers of the samples: SIRM (saturation isothermal remanent magnetization) decay curves (procedure after Kadziałko-Hofmokl & Kruczyk, 1976) and the three-component IRM (isothermal remanent magnetization) procedure described by Lowrie (1990). Experimental work has revealed the dominance of pyrrhotite and magnetite phases as carriers with soft-medium coercivity (samples are saturated in 0.2-0.4 T) and distinct unblocking temperatures around 320-350 ºC and 575-600 ºC respectively. Presented study is the part of PALMAG project 2012-2015: "Integration of palaeomagnetic, isotopic and structural data to understand Svalbard Caledonian Terranes assemblage" (see also Michalski et al. 2012), funded by Polish National Science Centre. References: HARLAND,W.B. 1997. The Geology of Svalbard. Geological Society of London, Memoir 17, 521 pp. KĄDZIOŁKO-HOFMOKL,M. & KRUCZYK,J. 1976. Complete and partial self-reversal of natural remanent magnetization of basaltic rocks from Lower Silesia, Poland. Pure and Applied Geophysics 110, 2031-40. LOWRIE,W. 1990. Identification of ferromagnetic minerals in a rock by coercivity and unblocking temperature properties. Geophysical Research Letters 17, 159-62. MICHALSKI,K., LEWANDOWSKI,M., MANBY,G.M. 2012. New palaeomagnetic, petrographic and 40Ar/39Ar data to test palaeogeographic reconstructions of Caledonide Svalbard. Cambridge University Press. Geological Magazine 149 (4), 696-721. RAMDOHR,P. 1980. The ore minerals and their intergrowths. Pergamon Press, Oxford.

  20. Postmortem whole-body magnetic resonance imaging as an adjunct to autopsy: preliminary clinical experience.

    Science.gov (United States)

    Patriquin, L; Kassarjian, A; Barish, M; Casserley, L; O'Brien, M; Andry, C; Eustace, S

    2001-02-01

    The purpose of this study was to evaluate whole-body magnetic resonance imaging (MRI) of cadavers as an adjunct to autopsy. Eight consecutive patients underwent both whole-body MRI and autopsy [either conventional (six), limited (one), or percutaneous (one)] within 24 hours of death. Comparison was made of major and minor abnormalities and predicted cause of death recorded by independent readers at both MRI and autopsy. Major discrepancies between the recorded primary cause of death at imaging and autopsy occurred in five (5) patients. These included a myocardial infarction found at autopsy alone, bowel infarction and portal venous gas found at MRI alone, and aortic dissection and occipital infarct found at MRI alone in a patient on whom only limited autopsy was performed. Postmortem MRI may represent a useful adjunct to autopsy, particularly in patients in whom autopsy is limited due to patient/family consent, inoculation risks, and ethnic doctrines.

  1. SUMMARY REPORT-FY2006 ITER WORK ACCOMPLISHED

    Energy Technology Data Exchange (ETDEWEB)

    Martovetsky, N N

    2006-04-11

    Six parties (EU, Japan, Russia, US, Korea, China) will build ITER. The US proposed to deliver at least 4 out of 7 modules of the Central Solenoid. Phillip Michael (MIT) and I were tasked by DoE to assist ITER in development of the ITER CS and other magnet systems. We work to help Magnets and Structure division headed by Neil Mitchell. During this visit I worked on the selected items of the CS design and carried out other small tasks, like PF temperature margin assessment.

  2. White matter integrity in Asperger syndrome: a preliminary diffusion tensor magnetic resonance imaging study in adults.

    Science.gov (United States)

    Bloemen, Oswald J N; Deeley, Quinton; Sundram, Fred; Daly, Eileen M; Barker, Gareth J; Jones, Derek K; van Amelsvoort, Therese A M J; Schmitz, Nicole; Robertson, Dene; Murphy, Kieran C; Murphy, Declan G M

    2010-10-01

    Autistic Spectrum Disorder (ASD), including Asperger syndrome and autism, is a highly genetic neurodevelopmental disorder. There is a consensus that ASD has a biological basis, and it has been proposed that it is a "connectivity" disorder. Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) allows measurement of the microstructural integrity of white matter (a proxy measure of "connectivity"). However, nobody has investigated the microstructural integrity of whole brain white matter in people with Asperger syndrome. We measured the fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD) of white matter, using DT-MRI, in 13 adults with Asperger syndrome and 13 controls. The groups did not differ significantly in overall intelligence and age. FA, MD and RD were assessed using whole brain voxel-based techniques. Adults with Asperger syndrome had a significantly lower FA than controls in 13 clusters. These were largely bilateral and included white matter in the internal capsule, frontal, temporal, parietal and occipital lobes, cingulum and corpus callosum. Adults with Asperger syndrome have widespread significant differences from controls in white matter microstructural integrity.

  3. Magnetic resonance imaging of the fetus in congenital intrathoracic disorders: preliminary observations

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiang; Ashtari, M.; Leonidas, J.C. [Dept. of Radiology, Schneider Children' s Hospital, Long Island Jewish Medical Center, NY (United States); Chan Ying [Fetal-Maternal Medicine, Schneider Children' s Hospital, Long Island Jewish Medical Center, and the Albert Einstein College of Medicine, NY (United States)

    2001-06-01

    Background and objective. Advances in magnetic resonance imaging (MRI) provide high-quality images of the intrathoracic organs. We studied the ability of MRI to define spatial relationships of the fetal lungs and measured lung volume in two cases of congenital diaphragmatic hernia (CDH), one of severe oligohydramnios secondary to bilateral cystic renal dysplasia and one case of prenatal chylothorax. Patients and methods. We performed pelvic MRI using single-shot fast spin echo (SSFSE) pulse sequence in four pregnant women referred because of abnormal prenatal ultrasound (US) findings associated with pulmonary hypoplasia. Results. The exact anatomic position of the contents of the hernia in CDH, including the position of the liver, was better defined with MRI. Pleural effusions were identified as well as the renal abnormality in the case of oligohydramnios. Lung volume was measured and the degree of pulmonary hypoplasia was quantified in every case. Lung-to-thorax ratio was calculated in the case of fetal chylothorax. Conclusion. Ongoing work suggests that MRI can provide additional detailed quantitative information in prenatal disorders associated with fetal lung compression and resulting hypoplasia. Correlation of fetal lung volume with postnatal management and outcome may affect prognosis in these cases. (orig.)

  4. Myocardial late gadolinium enhancement in specific cardiomyopathies by cardiovascular magnetic resonance: a preliminary experience.

    Science.gov (United States)

    Silva, Caterina; Moon, James C; Elkington, Andrew G; John, Anna S; Mohiaddin, Raad H; Pennell, Dudley J

    2007-12-01

    Late gadolinium enhancement cardiovascular magnetic resonance (CMR) can visualize myocardial interstitial abnormalities. The aim of this study was to assess whether regions of abnormal myocardium can also be visualized by late enhancement gadolinium CMR in the specific cardiomyopathies. A retrospective review of all referrals for gadolinium CMR with specific cardiomyopathy over 20 months. Nine patients with different specific cardiomyopathies were identified. Late enhancement was demonstrated in all patients, with a mean signal intensity of 390 +/- 220% compared with normal regions. The distribution pattern of late enhancement was unlike the subendocardial late enhancement related to coronary territories found in myocardial infarction. The affected areas included papillary muscles (sarcoid), the mid-myocardium (Anderson-Fabry disease, glycogen storage disease, myocarditis, Becker muscular dystrophy) and the global sub-endocardium (systemic sclerosis, Loeffler's endocarditis, amyloid, Churg-Strauss). Focal myocardial late gadolinium enhancement is found in the specific cardiomyopathies, and the pattern is distinct from that seen in infarction. Further systematic studies are warranted to assess whether the pattern and extent of late enhancement may aid diagnosis and prognostic assessment.

  5. Glucosamine sulfate effect on the degenerated patellar cartilage: preliminary findings by pharmacokinetic magnetic resonance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Marti-Bonmati, Luis [Dr Peset University Hospital, Radiology Department, Valencia (Spain); Hospital Quiron Valencia, Radiology Department, Valencia (Spain); Sanz-Requena, Roberto; Alberich-Bayarri, Angel [Hospital Quiron Valencia, Radiology Department, Valencia (Spain); Rodrigo, Jose Luis [Dr Peset University Hospital, Traumatology and Orthopedics Surgery Department, Valencia (Spain); Carot, Jose Miguel [Universidad Politecnica de Valencia, EIO Department, Valencia (Spain)

    2009-06-15

    Normal and degenerated cartilages have different magnetic resonance (MR) capillary permeability (K{sup trans}) and interstitial interchangeable volume (v{sub e}). Our hypothesis was that glucosamine sulfate treatment modifies these neovascularity abnormalities in osteoarthritis. Sixteen patients with patella degeneration, randomly distributed into glucosamine or control groups, underwent two 1.5-Tesla dynamic contrast-enhanced MR imaging studies (treatment initiation and after 6 months). The pain visual analog scale (VAS) and American Knee Society (AKS) score were used. A two-compartment pharmacokinetic model was used. Percentages of variations (postreatment-pretreatment/pretreatment) were compared (t-test for independent data). In the glucosamine group, pain and functional outcomes statistically improved (VAS: 7.3 {+-} 1.1 to 3.6 {+-} 1.3, p < 0.001; AKS: 18.6 {+-} 6.9 to 42.9 {+-} 2.7, p < 0.01). Glucosamine significantly increased K{sup trans} at 6 months (-54.4 {+-} 21.2% vs 126.7 {+-} 56.9%, p < 0.001, control vs glucosamine). In conclusion, glucosamine sulfate decreases pain while improving functional outcome in patients with cartilage degeneration. Glucosamine sulfate increases K{sup trans}, allowing its proposal as a surrogate imaging biomarker after 6 months of treatment. (orig.)

  6. Characteristic Dynamic Enhancement Pattern of Magnetic Resonance Imaging for Malignant Thyroid Tumor: A Preliminary Report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Young Nam; Hwang, Hee Young; Shim, Young Sup; Byun, Sung Su; Choi, Hye Young; Kim, Hyung Sik [Dept. of Radiology, Gil Hospital, Gachon University College of Medicine and Science, Incheon (Korea, Republic of)

    2011-11-15

    The purpose of this study is to determine the characteristic dynamic enhancement pattern of magnetic resonance (MR) imaging for malignant thyroid tumor. Eight patients who were pathology proven to have a malignant thyroid tumor, preoperatively. There are 5 papillary carcinomas, 1 medullary carcinoma, 1 follicular carcinoma, and 1 fine needle aspiration biopsy proven atypical cell. Based on preoperative MR imaging, we compared the dynamic MR enhancement pattern relating to the pathologic type. On contrast agent-enhanced dynamic T1-weighted image (T1WI), 5 papillary carcinoma and one medullary carcinoma showed delayed enhancement compared to normal parenchyma. In addition, one follicular carcinoma shows stronger enhancement than normal parenchyma, with one papillary carcinoma showing a persistent decrease in enhancement compared to normal parenchyma. Although this study is limited by a small patients population, the data suggests that delayed enhancement on enhanced dynamic T1WI is a possible characteristic MR finding of a malignant thyroid tumor. I think that the comparison of MR imaging between benign and malignant nodules is required for a correct characterization.

  7. ETR/ITER systems code

    Energy Technology Data Exchange (ETDEWEB)

    Barr, W.L.; Bathke, C.G.; Brooks, J.N.; Bulmer, R.H.; Busigin, A.; DuBois, P.F.; Fenstermacher, M.E.; Fink, J.; Finn, P.A.; Galambos, J.D.; Gohar, Y.; Gorker, G.E.; Haines, J.R.; Hassanein, A.M.; Hicks, D.R.; Ho, S.K.; Kalsi, S.S.; Kalyanam, K.M.; Kerns, J.A.; Lee, J.D.; Miller, J.R.; Miller, R.L.; Myall, J.O.; Peng, Y-K.M.; Perkins, L.J.; Spampinato, P.T.; Strickler, D.J.; Thomson, S.L.; Wagner, C.E.; Willms, R.S.; Reid, R.L. (ed.)

    1988-04-01

    A tokamak systems code capable of modeling experimental test reactors has been developed and is described in this document. The code, named TETRA (for Tokamak Engineering Test Reactor Analysis), consists of a series of modules, each describing a tokamak system or component, controlled by an optimizer/driver. This code development was a national effort in that the modules were contributed by members of the fusion community and integrated into a code by the Fusion Engineering Design Center. The code has been checked out on the Cray computers at the National Magnetic Fusion Energy Computing Center and has satisfactorily simulated the Tokamak Ignition/Burn Experimental Reactor II (TIBER) design. A feature of this code is the ability to perform optimization studies through the use of a numerical software package, which iterates prescribed variables to satisfy a set of prescribed equations or constraints. This code will be used to perform sensitivity studies for the proposed International Thermonuclear Experimental Reactor (ITER). 22 figs., 29 tabs.

  8. Robust iterative methods

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. The superconducting proposal for the CS magnet system of FAST: a preliminary analysis of the heat load due to AC losses

    CERN Document Server

    Pompeo, N

    2011-01-01

    FAST (Fusion Advanced Studies Torus), the Italian proposal of a Satellite Facility to ITER, is a compact tokamak (R$_0$ = 1.82 m, a = 0.64 m, triangularity $\\delta$ = 0.4) able to investigate non-linear dynamics effects of $\\alpha$-particle behavior in burning plasmas and to test technical solutions for the first wall/divertor directly relevant for ITER and DEMO. Currently, ENEA is investigating the feasibility of a superconducting solution for the magnet system. This paper focuses on the analysis of the CS (Central Solenoid) magnet thermal behavior. In particular, considering a superconducting solution for the CS which uses the room available in the resistive design and referring to one of the most severe scenario envisaged for FAST, the heat load of the CS winding pack due to AC losses is preliminarily evaluated. The results provide a tentative baseline for the definition of the strand requirements and conductor design, that can be accepted in order to fulfil the design requirements.

  10. CORSICA modelling of ITER hybrid operation scenarios

    Science.gov (United States)

    Kim, S. H.; Bulmer, R. H.; Campbell, D. J.; Casper, T. A.; LoDestro, L. L.; Meyer, W. H.; Pearlstein, L. D.; Snipes, J. A.

    2016-12-01

    The hybrid operating mode observed in several tokamaks is characterized by further enhancement over the high plasma confinement (H-mode) associated with reduced magneto-hydro-dynamic (MHD) instabilities linked to a stationary flat safety factor (q ) profile in the core region. The proposed ITER hybrid operation is currently aiming at operating for a long burn duration (>1000 s) with a moderate fusion power multiplication factor, Q , of at least 5. This paper presents candidate ITER hybrid operation scenarios developed using a free-boundary transport modelling code, CORSICA, taking all relevant physics and engineering constraints into account. The ITER hybrid operation scenarios have been developed by tailoring the 15 MA baseline ITER inductive H-mode scenario. Accessible operation conditions for ITER hybrid operation and achievable range of plasma parameters have been investigated considering uncertainties on the plasma confinement and transport. ITER operation capability for avoiding the poloidal field coil current, field and force limits has been examined by applying different current ramp rates, flat-top plasma currents and densities, and pre-magnetization of the poloidal field coils. Various combinations of heating and current drive (H&CD) schemes have been applied to study several physics issues, such as the plasma current density profile tailoring, enhancement of the plasma energy confinement and fusion power generation. A parameterized edge pedestal model based on EPED1 added to the CORSICA code has been applied to hybrid operation scenarios. Finally, fully self-consistent free-boundary transport simulations have been performed to provide information on the poloidal field coil voltage demands and to study the controllability with the ITER controllers. Extended from Proc. 24th Int. Conf. on Fusion Energy (San Diego, 2012) IT/P1-13.

  11. Quantum Iterated Function Systems

    CERN Document Server

    Lozinski, A; Slomczynski, W; Lozinski, Artur; Zyczkowski, Karol; Slomczynski, Wojciech

    2003-01-01

    Iterated functions system (IFS) is defined by specifying a set of functions in a classical phase space, which act randomly on the initial point. In an analogous way, we define quantum iterated functions system (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. We present exemplary classical IFSs, the invariant measure of which exhibits fractal structure, and study properties of the corresponding QIFSs and their invariant state.

  12. Localised proton magnetic resonance spectroscopy of the brain after perinatal hypoxia: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Chateil, J.F. [Service de Radiologie A, Hopital Pellegrin, Bordeaux (France)]|[Unite de Radiopediatrie, Hopital Pellegrin, Bordeaux (France); Quesson, B.; Thiaudiere, E.; Delalande, C.; Canioni, P. [Resonance Magnetique des Systemes Biologiques, CNRS, Bordeaux (France); Brun, M.; Diard, F. [Service de Radiologie A, Hopital Pellegrin, Bordeaux (France); Sarlangue, J.; Billeaud, C. [Service de Neonatalogie, Hopital Pellegrin, Bordeaux (France)

    1999-03-01

    Objectives. Perinatal hypoxic ischaemic injury is a significant cause of neurodevelopmental impairment. The aim of this study was to evaluate localised proton magnetic resonance spectroscopy ({sup 1}H-MRS) after birth asphyxia. Materials and methods. Thirty newborn infants suspected of having perinatal asphyxia (Apgar score < 3) were studied. The mean gestational age was 37 weeks, mean age at the MR examination was 18 days and mean weight was 2.9 kg. A 1.5-T unit was used for imaging and spectroscopy. None of the babies had mechanically assisted ventilation. No sedation was used. Axial T1-weighted and T2-weighted images were obtained. {sup 1}H-MRS was recorded in a single voxel, localised in white matter, using a STEAM sequence. Results. Image quality was good in 25 of 30 babies. {sup 1}H-MRS was performed in 19 of 30 subjects, with adequate quality in 16. Choline, creatine/phosphocreatine and N-acetylaspartate peaks and peak-area ratios were analysed. Lactate was detected in four infants. The N-acetylaspartate/choline ratio was lower in infants with an impaired neurological outcome, but the difference was not statistically significant. Conclusions. This study suggests that {sup 1}H-MRS may be useful for assessing cerebral metabolism in the neonate. A raised lactate level and decreased N-acetylaspartate/choline ratio may be predictive of a poor outcome. However, in our experience this method is limited by the difficulty in performing the examination during the first hours after birth in critically ill babies, the problems related to use of a monovoxel sequence, the dispersion of the ratios and the lack of determination of the absolute concentration of the metabolites. (orig.) With 3 figs., 2 tabs., 20 refs.

  13. Diffusion-weighted Magnetic Resonance Imaging in the Diagnosis of Bone Tumors: Preliminary Results

    Directory of Open Access Journals (Sweden)

    Yeliz Pekcevik

    2013-01-01

    Full Text Available Objective: The study aims to determine whether apparent diffusion coefficient (ADC can help differentiate benign and malignant bone tumors. Materials and Methods: From January 2012 to February 2013, we prospectively included 26 patients. Of these 15 patients were male and 11 were female; ranging in age from 8 to 76 years (mean age, 34.5 years. Diffusion-weighted magnetic resonance (MR imaging was obtained with a single-shot echo-planar imaging sequence using a 1.5T MR scanner. We grouped malignant lesions as primary, secondary, and primary tumor with chondroid matrix. The minimum ADC was measured in the tumors and mean minimum ADC values were selected for statistical analysis. ADC values were compared between malignant and benign tumors using the Mann-Whitney U-test and receiver operating curve analysis were done to determine optimal cut-off values. Results: The mean ADC values from the area with lowest ADC values of benign and malignant tumors were 1.99 ± 0.57 × 10−3 mm 2 /s and 1.02 ± 1.0 × 10−3 mm 2 /s, respectively. The mean minimum ADC values of benign and malignant tumors were statistically different (P = 0.029. With cut-off value of 1.37 (10−3 mm 2 /s, sensitivity was 77.8% and specificity was 82.4%, for distinguishing benign and malignant lesion. Benign and secondary malignant tumors showed statistically significant difference (P = 0.002. There was some overlap in ADC values between benign and malignant tumors. The mean minimum ADC values of benign and malignant chondroid tumors were high. Giant cell tumor, non-ossifying fibroma and fibrous dysplasia showed lower ADC values. Conclusion: Although there is some overlap, ADC values of benign and malignant bone tumors seem to be different. Further studies with larger patient groups are needed to find an optimal cut-off ADC value.

  14. Preliminary evaluation of magnetic resonance fresh blood imaging for diagnosis of Budd-Chiari syndrome

    Institute of Scientific and Technical Information of China (English)

    REN Ke; XU Ke; SUN Wen-ge; CHEN Yu-shuai; QI Xi-xun; LI Ran-liang; JIN An-yu

    2007-01-01

    Background Budd-Chiari syndrome (BCS) is a rare disease with portal hypertension caused by the blockage of the hepatic vein and/or the inferior vena cava (IVC). Angiography is the "golden standard" for diagnosis, but it is an invasive examination. To assess the diagnostic value of a fresh blood imaging (FBI) relative to BCS, we used a magnetic resonance angiography (MRA) with an FBI sequence for a preoperative evaluation of the BCS patients in this study. Methods Fifty patients who were suspected of having BCS after they had been checked by a B-ultrasound were studied. 2D and 3D FBI were performed on a 1.5T superconductive MR scanner. Original images were rebuilt using a maximal intensity projection (MIP) method on the console. Two doctors reviewed all images before they learned of the angiography results. We then compared the diagnoses obtained from the FBI and angiography results to evaluate the diagnostic value of the FBI.Results Forty-one patients were diagnosed as BCS and 9 as non-BCS based on an angiography. The FBI correctly diagnosed 38 patients, incorrectly diagnosed 1 patient, and missed diagnosis in 3 patients. Thus, the diagnostic sensitivity of the FBI is 93% (38/41), the specificity is 89% (8/9) and the accuracy is 92% (46/50). The FBI images of the 13 membranous stenoses of the IVC showed a sudden stenosis of the post-liver segment of the IVC. The Images of the 5 patients with a membranous obstruction of the IVC showed IVC thickening and an absence of blood signals in the post-hepatic segment of the IVC. The images of the 4 patients with the segmental thrombosis of the IVC showed abnormal and intermittent signals in the IVC. The images of the 6 patients with a simple hepatic vein obstruction showed obstructive hepatic veins. The images of the 6 patients with the stenosis of both the IVC and the hepatic veins showed the stenosis of the IVC, the thickening of the hepatic veins and the formation of a compensatory circulation within the liver. Lastly

  15. Real-time magnetic resonance imaging of deep venous flow during muscular exercise—preliminary experience

    Science.gov (United States)

    Merboldt, Klaus-Dietmar; Voit, Dirk; Dahm, Johannes; Frahm, Jens

    2016-01-01

    Background The accurate assessment of peripheral venous flow is important for the early diagnosis and treatment of disorders such as deep-vein thrombosis (DVT) which is a major cause of post-thrombotic syndrome or even death due to pulmonary embolism. The aim of this work is to quantitatively determine blood flow in deep veins during rest and muscular exercise using a novel real-time magnetic resonance imaging (MRI) method for velocity-encoded phase-contrast (PC) MRI at high spatiotemporal resolution. Methods Real-time PC MRI of eight healthy volunteers and one patient was performed at 3 Tesla (Prisma fit, Siemens, Erlangen, Germany) using a flexible 16-channel receive coil (Variety, NORAS, Hoechberg, Germany). Acquisitions were based on a highly undersampled radial FLASH sequence with image reconstruction by regularized nonlinear inversion at 0.5×0.5×6 mm3 spatial resolution and 100 ms temporal resolution. Flow was assessed in two cross-sections of the lower leg at the level of the calf muscle and knee using a protocol of 10 s rest, 20 s flexion and extension of the foot, and 10 s rest. Quantitative analyses included through-plane flow in the right posterior tibial, right peroneal and popliteal vein (PC maps) as well as signal intensity changes due to flow and muscle movements (corresponding magnitude images). Results Real-time PC MRI successfully monitored the dynamics of venous flow at high spatiotemporal resolution and clearly demonstrated increased flow in deep veins in response to flexion and extension of the foot. In normal subjects, the maximum velocity (averaged across vessel lumen) during exercise was 9.4±5.7 cm·s−1 for the right peroneal vein, 8.5±4.6 cm·s−1 for the right posterior tibial vein and 17.8±5.8 cm·s−1 for the popliteal vein. The integrated flow volume per exercise (20 s) was 1.9, 1.6 and 50 mL (mean across subjects) for right peroneal, right posterior tibial and popliteal vein, respectively. A patient with DVT presented with

  16. Preliminary results of endorectal surface coil magnetic resonance imaging for local staging of prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Jager, G.H. [Radiologische Universitaetsklinik, Nijmegen (Netherlands). Abt. fuer Abdominale Roentgendiagnostik; Barentsz, J.O. [Radiologische Universitaetsklinik, Nijmegen (Netherlands). Abt. fuer Abdominale Roentgendiagnostik; Rosette, J.J.M.C.H. de la [Medizinische Universitaetsklinik, Nijmegen (Netherlands). Abt. fuer Urologie; Rosenbusch, G. [Radiologische Universitaetsklinik, Nijmegen (Netherlands). Abt. fuer Abdominale Roentgendiagnostik

    1994-03-01

    Objective: To evaluate the effectiveness of endorectal surface coil (ERC) magnetic resonance imaging (MRI) in the local staging of adenocarcinoma of the prostate (ACP). Materials and methods: A total of 23 patients who were considered candidates for radical prostatectomy because of clinically localized ACP were examined by ERC-MRI. All patients underwent laparoscopic or open lymph-node dissection prior to surgery. Four patients had positive lymph nodes at operation. A total of 19 underwant radical prostatectomy, allowing comparison of the MRI data with the surgical pathologic findings. Results: Twelve patients had extraglandular spread of ACP (T3) and 7 had locally confined ACP (T2). ERC-MRI predicted correctly a T3 tumor in 10 of 12 cases and a T2 tumor in 4 of 7 cases. ERC-MRI was 74% accurate in differentiating T2 from T3 tumor. Three cases of overestimation were in studies with poor image quality because of bowel movement motion artifacts. Conclusion: ERC-MRI was found to be a sensitive modality in staging clinically localized ACP. (orig.) [Deutsch] Ziel: Bestimmung der Wertigkeit der Kernspintomographie (MRI) mit einer endorektalen Oberflaechenspule (ERC) fuer das lokale staging des Adenokarzinoms der Prostata (ACP). Material und Methode: Insgesamt 23 Patienten die als Kandidaten fuer eine radikale Prostatektomie wegen eines klinisch lokalisierten ACP galten, wurden mit ERC-MRI untersucht. Alle Patienten unterzogen sich einer laparoskopischen oder offenen Lymphdruesendissektion bei der Operation. Bei 19 Patienten, bei denen eine radikale Prostatektomie ausgefuehrt wurde, konnte eine Korrelation der MRI-Befunde mit denen der Operation erfolgen. Ergebnisse: Zwoelf Patienten wiesen extraglandulaere Ausbreitung des ACP (T3) auf und 7 hatten ein lokal begrenztes ACP (T2). ERC-MRI ergab korrekt einen T3-Tumor in 10 der 12 Faelle und einen T2-Tumor in 4 der 7 Faelle. Die Genauigkeit der ERC-MRI um einen T2- von einem T3-Tumor zu differenzieren betrug 74%. Bei drei

  17. Iterative List Decoding

    DEFF Research Database (Denmark)

    Justesen, Jørn; Høholdt, Tom; Hjaltason, Johan

    2005-01-01

    We analyze the relation between iterative decoding and the extended parity check matrix. By considering a modified version of bit flipping, which produces a list of decoded words, we derive several relations between decodable error patterns and the parameters of the code. By developing a tree...... of codewords at minimal distance from the received vector, we also obtain new information about the code....

  18. Iterative software kernels

    Energy Technology Data Exchange (ETDEWEB)

    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`.

  19. Implications for Fault and Basin Geometry in the Central California Coast Ranges from Preliminary Gravity and Magnetic Data

    Science.gov (United States)

    Langenheim, V. E.; Jachens, R. C.; Graymer, R. W.; Wentworth, C. M.

    2008-12-01

    Preliminary aeromagnetic and newly processed gravity data help define block-bounding faults and deep sedimentary basins in the central California Coast Ranges, ranging from the Hosgri fault east to the San Andreas fault and from Monterey Bay south to Pt. Conception. Interpretation of these data results in an improved framework for seismic hazard and groundwater studies. Aeromagnetic data include a new survey with a flight-line spacing of 800 m at a nominal 300 m above ground and covering 15,000 km2. More than 11,500 gravity measurements, reprocessed with terrain corrections calculated from 30-m DEMs, form a roughly 2-km grid over most of the study area. Combined potential-field data and existing geologic mapping, delineate major fault-bounded blocks in the central California Coast Ranges. Main block-bounding faults from west to east include the San Gregorio- Hosgri, San Luis-Willmar-Santa Maria River-Little Pine, Oceanic-West Huasna, Nacimiento, Rinconada-South Cuyama, San Juan-Chimineas-Morales, and San Andreas faults. Most of these faults have evidence of Quaternary activity. Gravity gradients indicate that the reach of the San Andreas fault bounding the Gabilan Range and the northern extension of the Rinconada fault bounding the Santa Lucia Range dip steeply southwestward and have a reverse component of slip. Magnetic and microseismicity data suggest that the northern reach of the Hosgri fault dips eastward. The potential-field data also delineate several deep sedimentary basins, such as the 3-4 km deep Cuyama basin, the Santa Maria basin, and several basins along and possibly offset by the Rinconada fault. Gravity data show that the main west-northwest-striking faults bounding the Cuyama basin dip away from the basin, indicating compression adjacent to the big bend in the San Andreas fault. Prominent gravity and magnetic highs northeast of the San Andreas fault immediately east of Cuyama Valley suggest that there the San Andreas fault dips southwest. Such dip

  20. Hyperpolarized {sup 3}He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Lindsay, E-mail: lmathew@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Kirby, Miranda, E-mail: mkirby@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Etemad-Rezai, Roya, E-mail: Roya.EtemadRezai@lhsc.on.ca [Department of Medical Imaging, University of Western Ontario (Canada); Wheatley, Andrew, E-mail: awheat@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); McCormack, David G., E-mail: David.McCormack@lhsc.on.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Division of Respirology, Department of Medicine, University of Western Ontario, London (Canada); Lawson Health Research Institute, London (Canada); Parraga, Grace, E-mail: gep@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Department of Medical Imaging, University of Western Ontario (Canada); Lawson Health Research Institute, London (Canada)

    2011-07-15

    Rationale and objectives: Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 ({sup 3}He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for {sup 3}He MRI in detecting the lung structural and functional COPD phenotypes. Materials and methods: We evaluated 20 ex-smokers with stage I (n = 1), stage II (n = 9) and stage III COPD (n = 10). All subjects underwent same-day plethysmography, spirometry, {sup 1}H MRI and hyperpolarized {sup 3}He MRI at 3.0 T. {sup 3}He ventilation defect percent (VDP) was generated from {sup 3}He static ventilation images and {sup 1}H thoracic images and the {sup 3}He apparent diffusion coefficient (ADC) was derived from diffusion-weighted MRI. Results: Based on the relative contribution of normalized ADC and VDP, there was evidence of a predominant {sup 3}He MRI measurement in seven patients (n = 3 mainly ventilation defects or VDP dominant (VD), n = 4 mainly increased ADC or ADC dominant (AD)). Analysis of variance (ANOVA) showed significantly lower ADC for subjects with predominantly elevated VDP (p = 0.02 compared to subjects with predominantly elevated ADC; p = 0.008 compared to mixed group) and significantly decreased VDP for subjects with predominantly elevated ADC (p = 0.003, compared to mixed group). Conclusion: In this small pilot study, a preliminary analysis shows the potential for {sup 3}He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.

  1. Europe wrestles with ITER site bid

    CERN Multimedia

    Feder, T

    2003-01-01

    "The European Union is in a quandary over whether to put forward the French or Spanish site to host ITER, a $5 billion magnetic fusion experiment intended to prove the feasability of fusion energy. The decision is set for 27 November, with the final site selection, between the victorious European bid and bids from Canada and Japan, to follow within a couple of months" (1 page)

  2. Iterative Algorithms for Nonexpansive Mappings

    Directory of Open Access Journals (Sweden)

    Yao Yonghong

    2008-01-01

    Full Text Available Abstract We suggest and analyze two new iterative algorithms for a nonexpansive mapping in Banach spaces. We prove that the proposed iterative algorithms converge strongly to some fixed point of .

  3. Final Report on ITER Task Agreement 81-10

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. 精化的二次残量迭代法%A REFINED RESIDUAL ITERATION METHOD

    Institute of Scientific and Technical Information of China (English)

    贾仲孝; 孙玉泉

    2004-01-01

    According to the refined projection principle advocated by Jia[8], we improve the residual iteration method of quadratic eigenvalue problems and propose a refined residual iteration method. We study the restarting issue of the method and develop a practical algorithm. Preliminary numerical examples illustrate the efficiency of the method.

  5. "One-Stop Shop": Free-Breathing Dynamic Contrast-Enhanced Magnetic Resonance Imaging of the Kidney Using Iterative Reconstruction and Continuous Golden-Angle Radial Sampling.

    Science.gov (United States)

    Riffel, Philipp; Zoellner, Frank G; Budjan, Johannes; Grimm, Robert; Block, Tobias K; Schoenberg, Stefan O; Hausmann, Daniel

    2016-11-01

    The purpose of the present study was to evaluate a recently introduced technique for free-breathing dynamic contrast-enhanced renal magnetic resonance imaging (MRI) applying a combination of radial k-space sampling, parallel imaging, and compressed sensing. The technique allows retrospective reconstruction of 2 motion-suppressed sets of images from the same acquisition: one with lower temporal resolution but improved image quality for subjective image analysis, and one with high temporal resolution for quantitative perfusion analysis. In this study, 25 patients underwent a kidney examination, including a prototypical fat-suppressed, golden-angle radial stack-of-stars T1-weighted 3-dimensional spoiled gradient-echo examination (GRASP) performed after contrast agent administration during free breathing. Images were reconstructed at temporal resolutions of 55 spokes per frame (6.2 seconds) and 13 spokes per frame (1.5 seconds). The GRASP images were evaluated by 2 blinded radiologists. First, the reconstructions with low temporal resolution underwent subjective image analysis: the radiologists assessed the best arterial phase and the best renal phase and rated image quality score for each patient on a 5-point Likert-type scale.In addition, the diagnostic confidence was rated according to a 3-point Likert-type scale. Similarly, respiratory motion artifacts and streak artifacts were rated according to a 3-point Likert-type scale.Then, the reconstructions with high temporal resolution were analyzed with a voxel-by-voxel deconvolution approach to determine the renal plasma flow, and the results were compared with values reported in previous literature. Reader 1 and reader 2 rated the overall image quality score for the best arterial phase and the best renal phase with a median image quality score of 4 (good image quality) for both phases, respectively. A high diagnostic confidence (median score of 3) was observed. There were no respiratory motion artifacts in any of the

  6. Iterative supervirtual refraction interferometry

    KAUST Repository

    Al-Hagan, Ola

    2014-05-02

    In refraction tomography, the low signal-to-noise ratio (S/N) can be a major obstacle in picking the first-break arrivals at the far-offset receivers. To increase the S/N, we evaluated iterative supervirtual refraction interferometry (ISVI), which is an extension of the supervirtual refraction interferometry method. In this method, supervirtual traces are computed and then iteratively reused to generate supervirtual traces with a higher S/N. Our empirical results with both synthetic and field data revealed that ISVI can significantly boost up the S/N of far-offset traces. The drawback is that using refraction events from more than one refractor can introduce unacceptable artifacts into the final traveltime versus offset curve. This problem can be avoided by careful windowing of refraction events.

  7. Iterative participatory design

    DEFF Research Database (Denmark)

    Simonsen, Jesper; Hertzum, Morten

    2010-01-01

    iterative process of mutual learning by designers and domain experts (users), who aim to change the users’ work practices through the introduction of information systems. We provide an illustrative case example with an ethnographic study of clinicians experimenting with a new electronic patient record......The theoretical background in this chapter is information systems development in an organizational context. This includes theories from participatory design, human-computer interaction, and ethnographically inspired studies of work practices. The concept of design is defined as an experimental...... system, focussing on emergent and opportunity-based change enabled by appropriating the system into real work. The contribution to a general core of design research is a reconstruction of the iterative prototyping approach into a general model for sustained participatory design....

  8. The Iterate Manual

    Science.gov (United States)

    1990-10-01

    is probably a bad idea. A better versica would use a temporary: (defmacro sum-of-squares (expr) (let ((temp ( gensym ))) ’(lot (,temp ,expr)) (sum...val ( gensym )) (tempi ( gensym )) (temp2 ( gensym )) (winner (or var iterate::*result-var*))) ’(progn (with ,max-val - nil) (with ,winner = nil) (cond ((null...the elements of a vector (disregards fill-pointer)" (let ((vect ( gensym )) (end ( gensym )) (index ( gensym ))) ’(progn (with ,vect - v) (with ,end = (array

  9. Iterative initial condition reconstruction

    Science.gov (United States)

    Schmittfull, Marcel; Baldauf, Tobias; Zaldarriaga, Matias

    2017-07-01

    Motivated by recent developments in perturbative calculations of the nonlinear evolution of large-scale structure, we present an iterative algorithm to reconstruct the initial conditions in a given volume starting from the dark matter distribution in real space. In our algorithm, objects are first moved back iteratively along estimated potential gradients, with a progressively reduced smoothing scale, until a nearly uniform catalog is obtained. The linear initial density is then estimated as the divergence of the cumulative displacement, with an optional second-order correction. This algorithm should undo nonlinear effects up to one-loop order, including the higher-order infrared resummation piece. We test the method using dark matter simulations in real space. At redshift z =0 , we find that after eight iterations the reconstructed density is more than 95% correlated with the initial density at k ≤0.35 h Mpc-1 . The reconstruction also reduces the power in the difference between reconstructed and initial fields by more than 2 orders of magnitude at k ≤0.2 h Mpc-1 , and it extends the range of scales where the full broadband shape of the power spectrum matches linear theory by a factor of 2-3. As a specific application, we consider measurements of the baryonic acoustic oscillation (BAO) scale that can be improved by reducing the degradation effects of large-scale flows. In our idealized dark matter simulations, the method improves the BAO signal-to-noise ratio by a factor of 2.7 at z =0 and by a factor of 2.5 at z =0.6 , improving standard BAO reconstruction by 70% at z =0 and 30% at z =0.6 , and matching the optimal BAO signal and signal-to-noise ratio of the linear density in the same volume. For BAO, the iterative nature of the reconstruction is the most important aspect.

  10. PREFACE: Progress in the ITER Physics Basis

    Science.gov (United States)

    Ikeda, K.

    2007-06-01

    fundamental to its completion. I am pleased to witness the extensive collaborations, the excellent working relationships and the free exchange of views that have been developed among scientists working on magnetic fusion, and I would particularly like to acknowledge the importance which they assign to ITER in their research. This close collaboration and the spirit of free discussion will be essential to the success of ITER. Finally, the PIPB identifies issues which remain in the projection of burning plasma performance to the ITER scale and in the control of burning plasmas. Continued R&D is therefore called for to reduce the uncertainties associated with these issues and to ensure the efficient operation and exploitation of ITER. It is important that the international fusion community maintains a high level of collaboration in the future to address these issues and to prepare the physics basis for ITER operation. ITPA Coordination Committee R. Stambaugh (Chair of ITPA CC, General Atomics, USA) D.J. Campbell (Previous Chair of ITPA CC, European Fusion Development Agreement—Close Support Unit, ITER Organization) M. Shimada (Co-Chair of ITPA CC, ITER Organization) R. Aymar (ITER International Team, CERN) V. Chuyanov (ITER Organization) J.H. Han (Korea Basic Science Institute, Korea) Y. Huo (Zengzhou University, China) Y.S. Hwang (Seoul National University, Korea) N. Ivanov (Kurchatov Institute, Russia) Y. Kamada (Japan Atomic Energy Agency, Naka, Japan) P.K. Kaw (Institute for Plasma Research, India) S. Konovalov (Kurchatov Institute, Russia) M. Kwon (National Fusion Research Center, Korea) J. Li (Academy of Science, Institute of Plasma Physics, China) S. Mirnov (TRINITI, Russia) Y. Nakamura (National Institute for Fusion Studies, Japan) H. Ninomiya (Japan Atomic Energy Agency, Naka, Japan) E. Oktay (Department of Energy, USA) J. Pamela (European Fusion Development Agreement—Close Support Unit) C. Pan (Southwestern Institute of Physics, China) F. Romanelli (Ente per le

  11. Development and test of the ITER SC conductor joints

    Energy Technology Data Exchange (ETDEWEB)

    Gung, C. Y.; Jayakumar, R.; Manahan, R.; Martovetsky, N.; Michael, P.; Minervini, J.; Randall, A.

    1998-08-05

    Joints for the ITER superconducting Central Solenoid should perform in rapidly varying magnetic field with low losses and low DC resistance. This paper describes the design of the ITER joint and presents its assembly process. Two joints were built and tested at the PTF facility at MIT. Test results are presented; losses in transverse and parallel field and the DC performance are discussed. The developed joint demonstrates sufficient margin for baseline ITRR operating scenarios.

  12. Stokes-Doppler coherence imaging for ITER boundary tomography

    Science.gov (United States)

    Howard, J.; Kocan, M.; Lisgo, S.; Reichle, R.

    2016-11-01

    An optical coherence imaging system is presently being designed for impurity transport studies and other applications on ITER. The wide variation in magnetic field strength and pitch angle (assumed known) across the field of view generates additional Zeeman-polarization-weighting information that can improve the reliability of tomographic reconstructions. Because background reflected light will be somewhat depolarized analysis of only the polarized fraction may be enough to provide a level of background suppression. We present the principles behind these ideas and some simulations that demonstrate how the approach might work on ITER. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

  13. MAGNET

    CERN Multimedia

    Benoit Curé

    The cooling down to the nominal temperature of 4.5 K was achieved at the beginning of August, in conjunction with the completion of the installation work of the connection between the power lines and the coil current leads. The temperature gradient on the first exchanger of the cold box is now kept within the nominal range. A leak of lubricant on a gasket of the helium compressor station installed at the surface was observed and several corrective actions were necessary to bring the situation back to normal. The compressor had to be refilled with lubricant and a regeneration of the filters and adsorbers was necessary. The coil cool down was resumed successfully, and the cryogenics is running since then with all parameters being nominal. Preliminary tests of the 20kA coil power supply were done earlier at full current through the discharge lines into the dump resistors, and with the powering busbars from USC5 to UXC5 without the magnet connected. On Monday evening August 25th, at 8pm, the final commissionin...

  14. ITER Cryoplant Final Design and Construction

    Science.gov (United States)

    Monneret, E.; Benkheira, L.; Fauve, E.; Henry, D.; Voigt, T.; Badgujar, S.; Chang, H.-S.; Vincent, G.; Forgeas, A.; Navion-Maillot, N.

    2017-02-01

    The ITER Tokamak supraconducting magnets, thermal shields and cryopumps will require tremendous amount of cooling power. With an average need of 75 kW at 4.5 K and of 600 kW at 80 K, ITER requires a world class cryogenic complex. ITER then relies on a Cryoplant which consists in a cluster of systems dedicated to the management of all fluids required for the Tokamak operation. From storage and purification to liquefaction and refrigeration, the Cryoplant will supply to the distribution system, all fluids to be circulated in the Tokamak. It includes Liquid Helium Plants and Liquid Nitrogen Plants, which generate all of the refrigeration power, an 80 K helium loop capable to circulate large quantities of helium through thermal shields, and all the auxiliaries required for gas storage, purification, and onsite nitrogen production. From the conceptual phase, the design of the Cryoplant has evolved and is now nearing completion. This proceeding will present the final design of the Cryoplant and the organization for the construction phase. Also the latest status of the ITER Cryogenic System will be introduced.

  15. Wall conditioning for ITER: Current experimental and modeling activities

    Energy Technology Data Exchange (ETDEWEB)

    Douai, D., E-mail: david.douai@cea.fr [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Kogut, D. [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Wauters, T. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Brezinsek, S. [FZJ, Institut für Energie- und Klimaforschung Plasmaphysik, 52441 Jülich (Germany); Hagelaar, G.J.M. [Laboratoire Plasma et Conversion d’Energie, UMR5213, Toulouse (France); Hong, S.H. [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Lomas, P.J. [CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Lyssoivan, A. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Nunes, I. [Associação EURATOM-IST, Instituto de Plasmas e Fusão Nuclear, 1049-001 Lisboa (Portugal); Pitts, R.A. [ITER International Organization, F-13067 St. Paul lez Durance (France); Rohde, V. [Max-Planck-Institut für Plasmaphysik, 85748 Garching (Germany); Vries, P.C. de [ITER International Organization, F-13067 St. Paul lez Durance (France)

    2015-08-15

    Wall conditioning will be required in ITER to control fuel and impurity recycling, as well as tritium (T) inventory. Analysis of conditioning cycle on the JET, with its ITER-Like Wall is presented, evidencing reduced need for wall cleaning in ITER compared to JET–CFC. Using a novel 2D multi-fluid model, current density during Glow Discharge Conditioning (GDC) on the in-vessel plasma-facing components (PFC) of ITER is predicted to approach the simple expectation of total anode current divided by wall surface area. Baking of the divertor to 350 °C should desorb the majority of the co-deposited T. ITER foresees the use of low temperature plasma based techniques compatible with the permanent toroidal magnetic field, such as Ion (ICWC) or Electron Cyclotron Wall Conditioning (ECWC), for tritium removal between ITER plasma pulses. Extrapolation of JET ICWC results to ITER indicates removal comparable to estimated T-retention in nominal ITER D:T shots, whereas GDC may be unattractive for that purpose.

  16. ERGODIC THEOREM FOR INFINITE ITERATED FUNCTION SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    O Hyong-chol; Ro Yong-hwa; Kil Won-gun

    2005-01-01

    A set of contraction maps of a metric space is called an iterated function systems.Iterated function systems with condensation can be considered infinite iterated function systems. Infinite iterated function systems on compact metric spaces were studied. Using the properties of Banach limit and uniform contractiveness, it was proved that the random iterating algorithms for infinite iterated function systems on compact metric spaces satisfy ergodicity. So the random iterating algorithms for iterated function systems with condensation satisfy ergodicity, too.

  17. Requirements for ITER diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Young, K.M.

    1991-01-01

    The development and design of plasma diagnostics for the International Thermonuclear Experimental Reactor (ITER) present a formidable challenge for experimental plasma physicists. The large plasma size, the high central density and temperature and the very high thermal wall loadings provide new challenges for present measurement techniques and lead to a search for new methods. But the physics and control requirements for the long burn phase of the discharge, combined with very limited access to the plasma, constrained by the requirement for radiation shielding of the coils and sharing of access ports with heating and current drive power, remote manipulation, fueling and turn blanket modules, make for very difficult design choices. An initial attempt at these choices has been made by an international team of diagnostic physicists, gathering together in a series of three workshops during the ITER Conceptual Design Activity. This paper is based on that report and provides a summary of its most important points. To provide a background against which to place the diagnostic requirements and design concepts, the ITER device, its most important plasma properties and the proposed experimental program will be described. The specifications for the measurement of the plasma parameters and the proposed diagnostics for these measurements will then be addressed, followed by some examples of the design concepts that have been proposed. As a result of these design studies, it was clear that there were many uncertainties associated with these concepts, particularly because of the nuclear radiation environment, so that a Research and Development Program for diagnostic hardware was established. It will also be briefly summarized.

  18. A simulation environment for ITER PCS development

    Energy Technology Data Exchange (ETDEWEB)

    Walker, M.L., E-mail: walker@fusion.gat.com [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Ambrosino, G.; De Tommasi, G. [CREATE/Università di Napoli Federcico II, Napoli (Italy); Humphreys, D.A. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Mattei, M. [Seconda Università di Napoli, Napoli (Italy); Neu, G.; Raupp, G.; Treutterer, W. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Winter, A. [ITER Organization, Route de Vinon-sur-Verdon, 13115 St. Paul-lez-Durance (France)

    2014-05-15

    Highlights: • Describes task to develop simulation tool to aid development/testing of ITER PCS. • Requirements and use cases and preliminary architecture have been delivered. • Detailed design is now being developed. • Provides overview of use cases and requirements. • Provides overview of architecture and status of development. - Abstract: A simulation environment known as the Plasma Control System Simulation Platform (PCSSP), specifically designed to support development of the ITER Plasma Control System (PCS), is currently under construction by an international team encompassing a cross-section of expertise in simulation and exception handling for plasma control. The proposed design addresses the challenging requirements of supporting the PCS design. This paper provides an overview of the PCSSP project and a discussion of some of the major features of its design. Plasma control for the ITER tokamak will be significantly more challenging than for existing fusion devices. An order of magnitude greater performance (e.g. [1,2]) is needed for some types of control, which together with limited actuator authority, implies that optimized individual controllers and nonlinear saturation logic are required. At the same time, consequences of control failure are significantly more severe, which implies a conflicting requirement for robust control. It also implies a requirement for comprehensive and robust exception handling. Coordinated control of multiple competing objectives with significant interactions, together with many shared uses of actuators to control multiple variables, implies that highly integrated control logic and shared actuator management will be required. It remains a challenge for the integrated technologies to simultaneously address these multiple and often competing requirements to be demonstrated on existing fusion devices and adapted for ITER in time to support its operational schedule. We describe ways in which the PCSSP will help address

  19. Iterative participatory design

    DEFF Research Database (Denmark)

    2010-01-01

    The theoretical background in this chapter is information systems development in an organizational context. This includes theories from participatory design, human-computer interaction, and ethnographically inspired studies of work practices. The concept of design is defined as an experimental...... iterative process of mutual learning by designers and domain experts (users), who aim to change the users’ work practices through the introduction of information systems. We provide an illustrative case example with an ethnographic study of clinicians experimenting with a new electronic patient record...

  20. Quantum iterated function systems.

    Science.gov (United States)

    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.

  1. Iterative Magnetometer Calibration

    Science.gov (United States)

    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.

  2. ITER LIDAR performance analysis.

    Science.gov (United States)

    Beurskens, M N A; Giudicotti, L; Kempenaars, M; Scannell, R; Walsh, M J

    2008-10-01

    The core LIDAR Thomson scattering for ITER is specified for core profile measurements with a spatial resolution of 7 cm (a/30) for the range of 500 eV3x10(19) m(-3) at an accuracy of system can meet its spatial and accuracy specifications for higher temperatures of T(e)>5 keV with a combination of a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (lambda(0)=1064 nm, Delta lambdanear infrared detectors.

  3. The Cryostat and Subsystems Development at ITER

    Science.gov (United States)

    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.

  4. Iterative guided image fusion

    Directory of Open Access Journals (Sweden)

    Alexander Toet

    2016-08-01

    Full Text Available We propose a multi-scale image fusion scheme based on guided filtering. Guided filtering can effectively reduce noise while preserving detail boundaries. When applied in an iterative mode, guided filtering selectively eliminates small scale details while restoring larger scale edges. The proposed multi-scale image fusion scheme achieves spatial consistency by using guided filtering both at the decomposition and at the recombination stage of the multi-scale fusion process. First, size-selective iterative guided filtering is applied to decompose the source images into approximation and residual layers at multiple spatial scales. Then, frequency-tuned filtering is used to compute saliency maps at successive spatial scales. Next, at each spatial scale binary weighting maps are obtained as the pixelwise maximum of corresponding source saliency maps. Guided filtering of the binary weighting maps with their corresponding source images as guidance images serves to reduce noise and to restore spatial consistency. The final fused image is obtained as the weighted recombination of the individual residual layers and the mean of the approximation layers at the coarsest spatial scale. Application to multiband visual (intensified and thermal infrared imagery demonstrates that the proposed method obtains state-of-the-art performance for the fusion of multispectral nightvision images. The method has a simple implementation and is computationally efficient.

  5. ITER helium ash accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, J.T.; Hillis, D.L.; Galambos, J.; Uckan, N.A. (Oak Ridge National Lab., TN (USA)); Dippel, K.H.; Finken, K.H. (Forschungszentrum Juelich GmbH (Germany, F.R.). Inst. fuer Plasmaphysik); Hulse, R.A.; Budny, R.V. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

    1990-01-01

    Many studies have shown the importance of the ratio {upsilon}{sub He}/{upsilon}{sub E} in determining the level of He ash accumulation in future reactor systems. Results of the first tokamak He removal experiments have been analysed, and a first estimate of the ratio {upsilon}{sub He}/{upsilon}{sub E} to be expected for future reactor systems has been made. The experiments were carried out for neutral beam heated plasmas in the TEXTOR tokamak, at KFA/Julich. Helium was injected both as a short puff and continuously, and subsequently extracted with the Advanced Limiter Test-II pump limiter. The rate at which the He density decays has been determined with absolutely calibrated charge exchange spectroscopy, and compared with theoretical models, using the Multiple Impurity Species Transport (MIST) code. An analysis of energy confinement has been made with PPPL TRANSP code, to distinguish beam from thermal confinement, especially for low density cases. The ALT-II pump limiter system is found to exhaust the He with maximum exhaust efficiency (8 pumps) of {approximately}8%. We find 1<{upsilon}{sub He}/{upsilon}{sub E}<3.3 for the database of cases analysed to date. Analysis with the ITER TETRA systems code shows that these values would be adequate to achieve the required He concentration with the present ITER divertor He extraction system.

  6. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Von Hellermann, M.; Giroud, C.; Jaspers, R. [Association Euratom-Fom, FOM Institute for Plasma Physics Rijnhuizen, Trilateral Euregio Cluster (Netherlands); Hawkes, N.C.; Mullane, M.O.; Zastrow, K.D. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Krasilnikov, A.; Tugarinov, S. [SRC RF TRINITI, Troitsk, Moscow region (Russian Federation); Lotte, P. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; McKee, G. [Wisconsin Univ., Madison, WI (United States); Malaquias, A. [Associacao EURATOM/IST, Instituto Superior Tecnico, Lisboa (Portugal); Rachlew, E. [Kungliga Tekniska Hoegskolan (KTH), Stockholm(Sweden)

    2003-07-01

    The latest status of 'Active Beam' related spectroscopy aspects as part of the ITER diagnostic scenario is presented. A key issue of the proposed scheme is based on the concept that in order to achieve the ultimate goal of global data consistency, all particles involved, that is, intrinsic and seeded impurity ions as well as helium ash ions and bulk plasma ions and also the plasma background data (e.g. magnetic and electric fields, electron density and temperature profiles) need to be addressed. A further sensible step in this direction is the decision of exploiting both a dedicated low-energy, low-power diagnostic beam (DNB, 2.2 MW 100 keV/amu) as well as the high-power, high-energy heating beams (HNB, 17 MW 500 keV/amu) for maximum diagnostic information. The authors report some new aspects referring to the use of DNB for motional Stark effect (MSE) where the main idea is to treat both beams (HNB and DNB) as potential diagnostic tools with complementary roles. The equatorial ports for the DNB promise excellent spatial resolution, however, the angles are less favourable for a polarimetric MSE exploitation. HNB can be used as probe beam for diagnosing slowing-down fusion alpha with a birth energy of 3,5 MeV.

  7. Physics of thermo-nuclear fusion and the ITER project; La physique de la fusion thermonucleaire et le projet ITER

    Energy Technology Data Exchange (ETDEWEB)

    Garin, P. [CEA Cadarache, Dept. de Recherches sur la Fusion Controlee - DRFC, 13 - Saint-Paul-lez-Durance (France)

    2003-01-01

    This document gathers the slides of the 6 contributions to the workshop 'the physics of thermo-nuclear fusion and the ITER project': 1) the feasibility of magnetic confinement and the issue of heat recovery, 2) heating and current generation in tokamaks, 3) the physics of wall-plasma interaction, 4) recent results at JET, 5) inertial confinement and fast ignition, and 6) the technology of fusion machines based on magnetic confinement. This document presents the principles of thermo-nuclear fusion machines and gives a lot of technical information about JET, Tore-Supra and ITER.

  8. Concept of magnet systems for LHD-type reactor

    Science.gov (United States)

    Imagawa, S.; Takahata, K.; Tamura, H.; Yanagi, N.; Mito, T.; Obana, T.; Sagara, A.

    2009-07-01

    Heliotron reactors have attractive features for fusion power plants such as having no need for current drive and a wide space between the helical coils for the maintenance of in-vessel components. Their main disadvantage was considered to be the necessarily large size of their magnet systems. According to the recent reactor studies based on the experimental results in the Large Helical Device, a major radius of plasma of 14-17 m with a central toroidal field of 6-4 T is needed to attain the self-ignition condition with a blanket space thicker than 1.1 m. The stored magnetic energy is estimated at 120-140 GJ. Although both the major radius and the magnetic energy are about three times as large as ITER, the maximum magnetic field and mechanical stress are comparable. In the preliminary structural analysis, the maximum stress intensity including the peak stress is less than the 1000 MPa that is allowed for strengthened stainless steel. Although the length of the helical coil is more than 150 m, that is about five times as long as the ITER TF coil, cable-in-conduit conductors can be adopted with a parallel winding method of five-in-hand. The concept of the parallel winding is proposed. Consequently, the magnet systems for helical reactors can be realized with a small extension of the ITER technology.

  9. Iterated crowdsourcing dilemma game

    Science.gov (United States)

    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.

  10. ITER components cooling: Satisfying the distinct needs of systems and components

    Energy Technology Data Exchange (ETDEWEB)

    Ployhar, Steven James, E-mail: steve.ployhar@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Gopalapillai, Babulal; Teodoros, Liliana Cristina; Dell Orco, Giovanni [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Kumar, Ajith; Gupta, Dinesh; Patel, Nirav; Jadhav, Mahesh Ashok [ITER-India, Institute for Plasma Research, A-29, GIDC Electronic Estate, Sector-25, Gandhinagar 382016, Gujarat (India)

    2014-10-15

    The ITER Tokamak requires multiple auxiliary systems to initiate, support, and monitor the fusion reaction. Heat produced by these systems, as well as the heat produced by the fusion reaction itself is collected by the ITER Cooling Water System (CWS) and rejected to the atmosphere. The CWS is composed of several systems designed for specific cooling roles. One of these systems is the Component Cooling Water System 2 (CCWS-2) whose function is to collect the heat from auxiliary client systems and components and transfer it to the Heat Rejection System. Clients are located throughout the site and have different requirements in terms of pressure, temperature, temperature variation, flow, metallurgy of wetted surfaces, and water quality. To satisfy these different requirements the CCWS-2 is divided into four separate loops, each of which has different operating parameters. For example, the CCWS-2A loop is designed to cool components with wetted surfaces of copper and primarily serves the radio-frequency heating systems, magnet power supplies, and neutral beam injector system components. This paper describes the evolution of the CCWS-2 system to match the needs of groups of compatible clients, and describes the development of the preliminary design of one of its loops, CCWS-2A, to meet individual client needs.

  11. ITER磁体支撑结构多维加载系统测控系统的设计%Design of the measurement and control system of multi-dimensional loading system for ITER magnet supports

    Institute of Scientific and Technical Information of China (English)

    廖敏; 李鹏远; 侯炳林; 潘传杰; 迟成芳

    2015-01-01

    In order to test the reliability of ITER magnet support structure, the multi-dimensional loading test platform was established for mechanical properties test of support components. The measurement and control system consists of seven sets of EDC controller and board, computer system, 16-channel quasi-dynamic strain gauge, 25 sets of displacement sensors, 7 sets of load and displacement sensors in the cylinders. On the basis of the programmable language, the measurment and control process for the muti-channel loading is realized, and the synchronizing control experiment with high precision for 7 sets of twin-cylinders is accomplished by using EDC220 digital controllers. Under the typical loading conditions, the engineering test result shows that the design of the system is rational, the control system is reliable, and it can guarantee the next requirement of the experiment.%为了验证ITER磁体支撑结构的可靠性,建立了多维加载测试平台对支撑部件进行机械性能检测。测量控制系统由7台EDC控制器、计算机系统、16通道准动态应变仪、25只位移传感器、7套油缸中的负荷和位移传感器组成。基于可编程语言,利用EDC220数字控制器实现了多通道协调加载的测量和控制过程,完成了7套双油缸高精度同步控制实验。针对典型的加载工况进行工程测试。结果表明,测控系统设计合理,控制系统可靠,能满足下一步的实验要求。

  12. Preliminary dielectric and rock magnetic results for a set of prehistoric Amerindian pottery samples from different Venezuelan Islands

    Science.gov (United States)

    Costanzo-Alvarez, V.; Suárez, N.; Aldana, M.; Hernández, M. C.; Campos, C.

    2006-10-01

    Potsherds from 7 Venezuelan islands have been studied using a two-fold magneto/dielectric technique in order to identify clay sources and characterize different stages of pottery craftsmanship. This is the first study of archeological material using this technique. Petrographic analyses appear to agree with the clusters of data identified in scatter plots of initial magnetic susceptibility versus saturation isothermal remanent magnetization (SIRM), and natural remanent magnetization (NRM). Thus, these magnetic parameters appear to be suitable for describing clay source characteristics. Effective magnetic grain sizes, investigated via stability analyses of SIRM and anystheretic remanent magnetization (ARM) upon alternating field (AF) demagnetization, and SIRM acquisition and AF demagnetization crossover plots, seem to be related to different steps of pottery craftsmanship, namely clay preparation, finishing and firing. Thermomagnetic curves might also provide valuable information about original firing conditions. A scatter plot of SIRMs intersections versus maximum current depolarization temperatures and average activation energies, shows a coarse correlation due perhaps to the fact that these rock magnetic and dielectric data are both associated to pore-related features.

  13. Seismic heating signatures in the Japan Trench subduction plate-boundary fault zone : evidence from a preliminary rock magnetic 'geothermometer'

    NARCIS (Netherlands)

    Yang, T.; Dekkers, M.J.|info:eu-repo/dai/nl/073463744; Zhang, Bo

    2016-01-01

    Frictional heating during earthquake rupture reveals important information on earthquake mechanisms and energy dissipation. The amount of annealing varies widely and is, as yet, poorly constrained. Here we use magnetic susceptibility versus temperature measurements during cycling to increasingly ele

  14. Use of movable high-field-strength intraoperative magnetic resonance imaging with awake craniotomies for resection of gliomas: preliminary experience.

    LENUS (Irish Health Repository)

    Leuthardt, Eric C

    2011-07-01

    Awake craniotomy with electrocortical mapping and intraoperative magnetic resonance imaging (iMRI) are established techniques for maximizing tumor resection and preserving function, but there has been little experience combining these methodologies.

  15. A preliminary attempt to identify atmospherically-derived pollution particles in English topsoils from magnetic susceptibility measurements

    Science.gov (United States)

    Hay, K. L.; Dearing, J. A.; Baban, S. M. J.; Loveland, P.

    This study identifies topsoils in England having increased magnetic susceptibility (xlf) values attributable to the presence of anthropogenically produced pollution particles, such as fly-ash. The database consists of 1176 topsoils taken at 10 km intervals across the whole of England, and tested for magnetic susceptibility at low and high frequencies. Soils containing significant concentrations of pollution particles were identified using two criteria; xlf (values > 0.38 10-6m3kg-1) and xfd% (values < 3%). The ‘polluted’ topsoils are located in the south-east around London, the Midlands, the north around the conurbations of Manchester, Merseyside and West Yorkshire, and in the north-east around Newcastle and Teeside. The heavy metal concentration of the soils are elevated above background levels, and have strong positive relationships with magnetic susceptibility and other magnetic parameters.

  16. Preliminary results of simulation of hypo magnetic conditions and variations in energetic range of cosmic rays in ground-based experiments on plant objects

    Science.gov (United States)

    Belisheva, Natalia; Petrashova, Dina; Shchegolev, Boris

    The most dangerous for the astronauts and cosmonauts are the cosmic rays and drastic decrease of the tension of geomagnetic field (GMF) on the Earth orbit and in the open space. The tension in the interplanetary magnetic field is 10 nT, whereas the tension of GMF is 10 (4) nT on the Earth surface. We carried out the preliminary experiments for study the effects of hypo magnetic conditions and variations in energetic range of cosmic rays (CR) on the plant objects (Vigna radiata, Phaseolus vulgaris, Allium cepa and A. fistulosum, Cucumis sativis). GMF was weakened by using special shielding chamber made on the basis of the amorphous alloy magnetic material. The camera is able to weaken the GMF from 48 μT till 0.192 μT. Modulation of the energetic range of the neutron component of secondary CR was performed with using of the shielding by graphite and by paraffin. The influence of hypo magnetic field and the neutron intensity were studied on the germination of seeds, the growth, the length and the side branches of the roots in the experimental samples. We found that the sensitivity to the hypo magnetic field and to the variations in energetic range of neutrons can vary from object to object. For instance, exposure of the hypo magnetic field on black bean and mung bean stimulated the growth of the roots while do not affect on the white bean. Likewise sensitivity of Phaseolus vulgaris (black and white bean) and Vigna radiata (mung bean) to exposure of nucleon component of cosmic rays on the Earth's surface are differed. It was found that modification of energetic range of CR by using graphite shielding leads to a change in sign of correlation between the length of roots in all experimental samples and the nucleon component of CR compared with the control samples. This is evidence that physiology of biological objects significantly are modified in hypo magnetic environment, as well as under exposure of the CR in different energetic ranges during the space flights. Our

  17. Selectively reduced responses to smoking cues in amygdala following extinction-based smoking cessation: results of a preliminary functional magnetic resonance imaging study.

    Science.gov (United States)

    McClernon, F Joseph; Hiott, F Berry; Liu, Jim; Salley, Alfred N; Behm, Frederique M; Rose, Jed E

    2007-09-01

    Preliminary studies suggest an extinction-based smoking cessation treatment using reduced nicotine content (RNC) cigarettes decreases self-report craving for cigarettes prior to quitting and may be an effective smoking cessation treatment. The aims of this study was to evaluate the effect of an extinction-based smoking cessation treatment on brain responses to smoking cues using blood-oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI). Sixteen (n = 16) dependent smokers were scanned using BOLD fMRI at baseline, following 2-4 weeks of smoking RNC cigarettes while wearing a 21-mg nicotine patch, and 2-4 weeks following quitting smoking. During scanning, participants viewed smoking-related pictures (e.g. lit cigarette) and pictures of people engaged in everyday activities (e.g. using a stapler). Event-related BOLD responses to smoking and control cues were analyzed in regions of interest (ROIs) known to subserve reward, attention, motivation and emotion. The extinction-based treatment simultaneously attenuated responses to smoking cues in amygdala while potentiating responses to control cues. Exploratory analysis indicated that this pattern was also observed in the thalamus of future abstinent but not relapsing smokers. The results of this preliminary study suggest that an extinction-based treatment for smoking cessation alters brain responses to smoking and control cues in amygdala--a region previously associated with drug cue reactivity and extinction.

  18. Preliminary research on overmoded high-power millimeter-wave Cerenkov generator with dual-cavity reflector in low guiding magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Hu; Wu, Ping [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an, Shaanxi 710024 (China); Chen, Changhua; Ning, Hui; Tan, Weibing; Teng, Yan; Shi, Yanchao; Song, Zhimin; Cao, Yibing; Du, Zhaoyu [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an, Shaanxi 710024 (China)

    2015-12-15

    This paper presents preliminary research on a V-band overmoded Cerenkov generator with dual-cavity reflector operating in a low guiding magnetic field. It is found that the fluctuation of the electron envelope in the low guiding magnetic field can be predicted using an equivalent coaxial model of a foilless diode, and a dual-cavity reflector based on the model matching method can provide strong reflection at the front end of the overmoded structures so that any microwave power that leaks into the diode region can be effectively suppressed. Numerical simulations indicate that the control of the beam envelope and the use of the dual-cavity reflector ease generator operation in the low guiding magnetic field. In the experimental research, the fluctuation of the annular electron beam with the outer radius of 7.5 mm measures approximately 0.7 mm, which is in good agreement with the theoretical results. The disturbance caused by power leaking from the overmoded slow wave structure is eliminated by the dual-cavity reflector. With accurate fabrication and assembly processes, an operating frequency of 61.6 GHz is attained by the fifth harmonic heterodyne method, and the output power is measured to be approximately 123 MW by the far-field measurement method at a diode voltage of 445 kV, a beam current of 4.45 kA, and under a guiding magnetic field of 1.45 T. The output mode is measured using an array of neon flash bulbs, and the pulse shortening phenomenon is both observed and analyzed.

  19. Some geometrical iteration methods for nonlinear equations

    Institute of Scientific and Technical Information of China (English)

    LU Xing-jiang; QIAN Chun

    2008-01-01

    This paper describes geometrical essentials of some iteration methods (e.g. Newton iteration,secant line method,etc.) for solving nonlinear equations and advances some geomet-rical methods of iteration that are flexible and efficient.

  20. A Preliminary, Full Spectrum, Magnetic Anomaly Grid of the United States with Improved Long Wavelengths for Studying Continental Dynamics

    Science.gov (United States)

    Ravat, Dhananjay; Korhonen, Juha

    2010-05-01

    Under an initiative started by Thomas G. Hildenbrand of the U.S. Geological Survey, we have improved the long-wavelength (50-2,500 km) content of the regional magnetic anomaly compilation for the conterminous United States by utilizing a nearly homogeneous set of National Uranium Resource Evaluation (NURE) magnetic surveys flown from 1975 to 1981. The surveys were flown in quadrangles of 2° of longitude by 1° of latitude with east-west flight lines spaced 4.8 to 9.6 km apart, north-south tie lines variably spaced, and a nominal terrain clearance of 122 m. The NURE surveys were processed using the Comprehensive Magnetic Field Model (Sabaka et al. 2004) to remove the core field for the epochs of the surveys. Many of the surveys used base-station magnetometers to remove external field variations. This NURE magnetic anomaly field is merged with the short-wavelengths from the North American Magnetic Anomaly Map (ca. 2002) to create a full spectrum database called NURE_NAMAM2008. http://pubs.usgs.gov/of/2009/1258/

  1. PICARD ITERATION FOR NONSMOOTH EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Song-bai Sheng; Hui-fu Xu

    2001-01-01

    This paper presents an analysis of the generalized Newton method, approximate Newton methods, and splitting methods for solving nonsmooth equations from Picard iteration viewpoint. It is proved that the radius of the weak Jacobian (RGJ) of Picard iteration function is equal to its least Lipschitz constant. Linear convergence or superlinear convergence results can be obtained provided that RGJ of the Picard iteration function at a solution point is less than one or equal to zero. As for applications, it is pointed out that the approximate Newton methods, the generalized Newton method for piecewise C1problems and splitting methods can be explained uniformly with the same viewpoint.

  2. Remote maintenance development for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Shibanuma, Kiyoshi

    1998-04-01

    This paper describes the overall ITER remote maintenance design concept developed mainly for in-vessel components such as diverters and blankets, and outlines the ITER R and D program to develop remote handling equipment and radiation hard components. Reactor structures inside the ITER cryostat must be maintained remotely due to DT operation, making remote handling technology basic to reactor design. The overall maintenance scenario and design concepts have been developed, and maintenance design feasibility, including fabrication and testing of full-scale in-vessel remote maintenance handling equipment and tool, is being verified. (author)

  3. Iterative optimization in inverse problems

    CERN Document Server

    Byrne, Charles L

    2014-01-01

    Iterative Optimization in Inverse Problems brings together a number of important iterative algorithms for medical imaging, optimization, and statistical estimation. It incorporates recent work that has not appeared in other books and draws on the author's considerable research in the field, including his recently developed class of SUMMA algorithms. Related to sequential unconstrained minimization methods, the SUMMA class includes a wide range of iterative algorithms well known to researchers in various areas, such as statistics and image processing. Organizing the topics from general to more

  4. Double Star, Cluster, and ground-based observations of magnetic reconnection during an interval of duskward oriented IMF: preliminary results

    Directory of Open Access Journals (Sweden)

    J. A. Wild

    2005-11-01

    Full Text Available We present a space- and ground-based study exploiting data from the coordinated Cluster and Double Star missions in order to investigate dayside magnetic reconnection under BY+ dominated IMF conditions. In-situ observations of magnetosheath flux transfer events combined with measurements of pulsed poleward and dawnward directed flows in the pre-noon sector high-latitude northern hemisphere ionosphere are interpreted as indications of pulsed magnetic reconnection during an interval in which the IMF remained relatively steady. Observations of newly-reconnected magnetic flux tubes anchored in the northern hemisphere both at mid-latitudes and in the vicinity of the subsolar point suggests that during BY+ dominated IMF, reconnection is not, as proposed previously, limited to the high-latitude magnetopause.

  5. Magnetic Fields of Be Stars: Preliminary Results from a Hybrid Analysis of the MiMeS Sample

    Science.gov (United States)

    Wade, G. A.; Petit, V.; Grunhut, J. H.; Neiner, C.; MiMeS Collaboration

    2016-11-01

    In the context of the MiMeS survey of magnetism in massive stars, 85 classical Be stars were observed in circular polarization with the aim of detecting magnetic fields at their surfaces. No direct evidence of such fields is found, in contrast to the significant rate of detection (5-10%) in non-Be B-type stars. In this paper we describe the sample properties, the methodology and the data quality. We describe a novel method, previously applied to Herbig Ae/Be stars, that allows us to infer upper limits on organized (dipolar) magnetic fields present in the photospheres of our targets. We review the characteristics and robustness of this null result, and discuss its implications.

  6. Preliminary Interpretations of Multi-Channel Seismic Reflection and Magnetic Data on North Anatolian Fault (NAF) in the Eastern Marmara Region, Turkey

    Science.gov (United States)

    Gözde Okut Toksoy, Nigar; Kurt, Hülya; İşseven, Turgay

    2017-04-01

    of Istanbul Technical University is used for processing. Proton magnetometer is used for measuring the magnetic field variations on the one of the profiles. Total magnetic field values are corrected using base readings from Bogazici University Kandilli Observatory, Iznik Earthquake Hazard Mitigation Center. Processed seismic and magnetic data are interpreted and compared to see effect of the NAF. Preliminary interpretations show vertical seismic discontinuities related to the fault figured out on the time-migrated seismic sections from surface to the about 1 s two-way travel time depth. Magnetic anomalies are also realized on the profile related to the NAF supporting the seismic data.

  7. The ITER Neutral Beam Test Facility towards SPIDER operation

    Science.gov (United States)

    Toigo, V.; Dal Bello, S.; Gaio, E.; Luchetta, A.; Pasqualotto, R.; Zaccaria, P.; Bigi, M.; Chitarin, G.; Marcuzzi, D.; Pomaro, N.; Serianni, G.; Agostinetti, P.; Agostini, M.; Antoni, V.; Aprile, D.; Baltador, C.; Barbisan, M.; Battistella, M.; Boldrin, M.; Brombin, M.; Dalla Palma, M.; De Lorenzi, A.; Delogu, R.; De Muri, M.; Fellin, F.; Ferro, A.; Gambetta, G.; Grando, L.; Jain, P.; Maistrello, A.; Manduchi, G.; Marconato, N.; Pavei, M.; Peruzzo, S.; Pilan, N.; Pimazzoni, A.; Piovan, R.; Recchia, M.; Rizzolo, A.; Sartori, E.; Siragusa, M.; Spada, E.; Spagnolo, S.; Spolaore, M.; Taliercio, C.; Valente, M.; Veltri, P.; Zamengo, A.; Zaniol, B.; Zanotto, L.; Zaupa, M.; Boilson, D.; Graceffa, J.; Svensson, L.; Schunke, B.; Decamps, H.; Urbani, M.; Kushwah, M.; Chareyre, J.; Singh, M.; Bonicelli, T.; Agarici, G.; Garbuglia, A.; Masiello, A.; Paolucci, F.; Simon, M.; Bailly-Maitre, L.; Bragulat, E.; Gomez, G.; Gutierrez, D.; Mico, G.; Moreno, J.-F.; Pilard, V.; Chakraborty, A.; Baruah, U.; Rotti, C.; Patel, H.; Nagaraju, M. V.; Singh, N. P.; Patel, A.; Dhola, H.; Raval, B.; Fantz, U.; Fröschle, M.; Heinemann, B.; Kraus, W.; Nocentini, R.; Riedl, R.; Schiesko, L.; Wimmer, C.; Wünderlich, D.; Cavenago, M.; Croci, G.; Gorini, G.; Rebai, M.; Muraro, A.; Tardocchi, M.; Hemsworth, R.

    2017-08-01

    SPIDER is one of two projects of the ITER Neutral Beam Test Facility under construction in Padova, Italy, at the Consorzio RFX premises. It will have a 100 keV beam source with a full-size prototype of the radiofrequency ion source for the ITER neutral beam injector (NBI) and also, similar to the ITER diagnostic neutral beam, it is designed to operate with a pulse length of up to 3600 s, featuring an ITER-like magnetic filter field configuration (for high extraction of negative ions) and caesium oven (for high production of negative ions) layout as well as a wide set of diagnostics. These features will allow a reproduction of the ion source operation in ITER, which cannot be done in any other existing test facility. SPIDER realization is well advanced and the first operation is expected at the beginning of 2018, with the mission of achieving the ITER heating and diagnostic NBI ion source requirements and of improving its performance in terms of reliability and availability. This paper mainly focuses on the preparation of the first SPIDER operations—integration and testing of SPIDER components, completion and implementation of diagnostics and control and formulation of operation and research plan, based on a staged strategy.

  8. Precisions on the structure of the Basque Arc (western Pyrenees, Spain): preliminary results from magnetic fabrics from the Biscay Synclinorium

    Science.gov (United States)

    Vegas, Néstor; Aranguren, Aitor; Rodríguez-Méndez, Lidia; Cuevas, Julia; María Tubía, José; Julián Esteban, José

    2017-04-01

    The Mesozoic Basque-Cantabrian basin (western Pyrenees) was inverted during the Alpine Orogeny in late Cretaceous-Eocene times. The central sector of the basin, the Basque Arc is characterized by the existence of large folds (80 km long) that outline an arc. This study focuses on the interpretation of AMS fabrics in rocks from the Biscay Synclinorium, a major fold system of the Basque Arc that verges to the NE, with sub-horizontal, N110˚ E trending axes and axial planes striking to N110˚ E and dipping steeply to the SW (Calvo-Rathert et al., 2007). The aim of this contribution is characterize the deformation around the Biscay Synclinorium. For this reason we combined fieldwork with magnetic fabric analysis of 95 cores in Upper Cretaceous sedimentary rocks of the Biscay Synclinorium. 68 cores come from the Calcareous formation (marls, sandy limestones and limestones of Cenomanian to Campanian age) that makes part of the northeastern limb of the synclinorium and the remaining 27 cores from the Detrital-calcareous flysch (a multilayer sequence with sandy limestones and marls of Maastrichtian age) that crops out in the synclinorium core (Garrote et al., 1991). In the Upper Cretaceous Calcareous formation there is a penetrative cleavage that mainly strikes to N110˚ E dipping 50˚ to 60˚ to the SW (S1). In the Detrital-calcareous flysch of the core, the best-preserved planar structure is the bedding and only locally an axial planar cleavage is observed. Intersection lineations are sub-horizontal and N110˚ E-trending. The measurements of the magnetic susceptibility provide low k values ranging between 99x10-6 and 403x10-6 SI. The anisotropy of the magnetic susceptibility, P, reaches values of 1.213, pointing to the overprinting of tectonic deformation on primary magnetic fabrics of sedimentary origin. The magnetic foliation shows a fairly uniform arrangement that is nearly coincident with the dominant planar structures of the rocks, S0 or S1in the core and the limb

  9. Evaluation of ITER MSE Viewing Optics

    Energy Technology Data Exchange (ETDEWEB)

    Allen, S; Lerner, S; Morris, K; Jayakumar, J; Holcomb, C; Makowski, M; Latkowski, J; Chipman, R

    2007-03-26

    The Motional Stark Effect (MSE) diagnostic on ITER determines the local plasma current density by measuring the polarization angle of light resulting from the interaction of a high energy neutral heating beam and the tokamak plasma. This light signal has to be transmitted from the edge and core of the plasma to a polarization analyzer located in the port plug. The optical system should either preserve the polarization information, or it should be possible to reliably calibrate any changes induced by the optics. This LLNL Work for Others project for the US ITER Project Office (USIPO) is focused on the design of the viewing optics for both the edge and core MSE systems. Several design constraints were considered, including: image quality, lack of polarization aberrations, ease of construction and cost of mirrors, neutron shielding, and geometric layout in the equatorial port plugs. The edge MSE optics are located in ITER equatorial port 3 and view Heating Beam 5, and the core system is located in equatorial port 1 viewing heating beam 4. The current work is an extension of previous preliminary design work completed by the ITER central team (ITER resources were not available to complete a detailed optimization of this system, and then the MSE was assigned to the US). The optimization of the optical systems at this level was done with the ZEMAX optical ray tracing code. The final LLNL designs decreased the ''blur'' in the optical system by nearly an order of magnitude, and the polarization blur was reduced by a factor of 3. The mirror sizes were reduced with an estimated cost savings of a factor of 3. The throughput of the system was greater than or equal to the previous ITER design. It was found that optical ray tracing was necessary to accurately measure the throughput. Metal mirrors, while they can introduce polarization aberrations, were used close to the plasma because of the anticipated high heat, particle, and neutron loads. These mirrors

  10. Rollout sampling approximate policy iteration

    NARCIS (Netherlands)

    Dimitrakakis, C.; Lagoudakis, M.G.

    2008-01-01

    Several researchers have recently investigated the connection between reinforcement learning and classification. We are motivated by proposals of approximate policy iteration schemes without value functions, which focus on policy representation using classifiers and address policy learning as a

  11. Iterative solution of linear systems

    Science.gov (United States)

    Freund, Roland W.; Golub, Gene H.; Nachtigal, Noel M.

    1992-01-01

    Recent advances in the field of iterative methods for solving large linear systems are reviewed. The main focus is on developments in the area of conjugate gradient-type algorithms and Krylov subspace methods for nonHermitian matrices.

  12. Cooperation between CERN and ITER

    CERN Multimedia

    2008-01-01

    CERN and the International Fusion Organisation ITER have just signed a first cooperation agreeement. Kaname Ikeda, the Director-General of the International Fusion Energy Organisation (ITER) (on the right) and Robert Aymar, Director-General of CERN, signing the agreement.The Director-General of the International Fusion Energy Organization, Mr Kaname Ikeda, and CERN Director-General, Robert Aymar, signed a cooperation agreement at a meeting on the Meyrin site on Thursday 6 March. One of the main purposes of this agreement is for CERN to give ITER the benefit of its experience in the field of technology as well as in administrative domains such as finance, procurement, human resources and informatics through the provision of consultancy services. Currently in its start-up phase at its Cadarache site, 70 km from Marseilles (France), ITER will focus its research on the scientific and technical feasibility of using fusion energy as a fu...

  13. Elmo Bumpy Torus proof of principle. Phase II. Title 1 report. Volume III. Magnet system. Preliminary design report

    Energy Technology Data Exchange (ETDEWEB)

    Ackerman, S.

    1982-02-26

    During Title I, General Dynamics' principal role as a subcontractor to the McDonnell Douglas Astronautics Company (MDAC) is to assist in the further development of a low-cost superconducting magnet mirror coil system for the EBT-P program consistent with long life and dependable operation. The activity can best be defined as an extension of ORNL's previous development program with further joint ORNL/MDAC/GDC refining of the mirror coil components. MDAC/GDC participation for the entire program can be subdivided into four distinct elements as follows: (1) design, development, and fabrication of two dewar subassemblies to enclose the ORNL developed and fabricated cold mass assemblies; (2) design, development, and fabrication of a production prototype magnet system including conductor (procurement), cold mass components, dewar and x-ray shield. This prototype would form the basis for the production of 36 magnets for the torus and three spares. (3) design, development, and fabrication of an electrical/electronic system including quench protection, instrumentation and control, and power supply to power and protect the mirror coil system during its operation in the torus; (4) fabrication of the 39 production magnets.

  14. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    Science.gov (United States)

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  15. A preliminary exploration of the mechanism for the occur rence of two types of various magnetic structures in the magnetotail

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As well known, the magnetic cross-tail component B y in the magnetotail is in direct proportion to the interplanetary magnetic field (IMF) B y component. And the polarity of IMF and plasmoid / flux rope B y components do indeed agree. This results indicate that the IMF B y pene-trates plasmoids and the magnetic structures must therefore be three-dimensional. In this note, the dynamical processes of magnetotail in the course of a substorm are studied using a MHD code with two-dimensions and three components on the basis of two types of initial equilibrium solutions of the quiet magnetotail. The numerical results of two cases illus-trate various features of time evolution of B y component that correspond to two kinds of plasmoid-like structures: one is associated with a flux rope core and the other resembles a "closed loop" plamoid. Therefore, the occurrence of various magnetic structures in the magnetotail might be related to nonsteady driven reconnection with different distributions of the B y component.

  16. Investigation on raspberry-like magnetic-hollow silica nanospheres and its preliminary application for drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunlei; Yan, Juntao, E-mail: yanjuntaonihao@163.com [Wuhan Polytechnic University, College of Chemistry and Environmental Engineering (China); Li, Zhanfeng; Wang, Hongyan; Cui, Xuejun [Jilin University, College of Chemistry (China)

    2013-09-15

    A series of raspberry-like magnetic-hollow silica nanospheres were successfully synthesized via the sol-gel process, which was based on the principle of the electrostatic interaction between negatively charged silica and positively charged polystyrene. The Fe{sub 3}O{sub 4}@SiO{sub 2} particles as the outer shell were compactly assembled on the surface of PS, and then magnetic-hollow nanospheres were obtained by calcination. Different synthesis conditions including the amount of NH{sub 4}OH, TEOS, Fe{sub 3}O{sub 4}, and the adding time of PS were systematically investigated to discuss the influence of these conditions on the morphology and structure. The prepared magnetic-hollow nanospheres were systematically characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared spectrometry, energy-dispersive X-ray analysis, thermogravimetric analysis and nitrogen adsorption-desorption measurement. SEM and TEM images exhibited that the obtained samples with the perfect spherical profile and large cavities structure were well monodisperse and uniform under the optimized condition. Zeta-potential analysis was employed to make clear the formation mechanism of raspberry-like PS@Fe{sub 3}O{sub 4}@SiO{sub 2} composite nanosphere. Moreover, the drug release of ibuprofen experiment results demonstrated that the magnetic-hollow nanospheres could be used as a drug carrier to slowly release and deliver drugs.

  17. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    Science.gov (United States)

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  18. ITER leader to head CERN

    CERN Multimedia

    Feder, Toni

    2003-01-01

    After successfully chairing an external review committee for CERN last year, Robert Aymar will leave ITER to become director general of the European particle physics laboratory rom 2004. Before ITER he also successfully managed the startup or Tore Supra. He will attempt to ensure that the LHC begins operating in 2007 - two years late - and is paid for by 2010 and will also start the planning for life after the LHC (1 page)

  19. ITER diagnostic system: Vacuum interface

    Energy Technology Data Exchange (ETDEWEB)

    Patel, K.M., E-mail: Kaushal.Patel@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Udintsev, V.S.; Hughes, S.; Walker, C.I.; Andrew, P.; Barnsley, R.; Bertalot, L. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Drevon, J.M. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Encheva, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Kashchuk, Y. [Institution “PROJECT CENTER ITER”, 1, Akademika Kurchatova pl., Moscow (Russian Federation); Maquet, Ph. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Pearce, R.; Taylor, N.; Vayakis, G.; Walsh, M.J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France)

    2013-10-15

    Diagnostics play an essential role for the successful operation of the ITER tokamak. They provide the means to observe control and to measure plasma during the operation of ITER tokamak. The components of the diagnostic system in the ITER tokamak will be installed in the vacuum vessel, in the cryostat, in the upper, equatorial and divertor ports, in the divertor cassettes and racks, as well as in various buildings. Diagnostic components that are placed in a high radiation environment are expected to operate for the life of ITER. There are approx. 45 diagnostic systems located on ITER. Some diagnostics incorporate direct or independently pumped extensions to maintain their necessary vacuum conditions. They require a base pressure less than 10{sup −7} Pa, irrespective of plasma operation, and a leak rate of less than 10{sup −10} Pa m{sup 3} s{sup −1}. In all the cases it is essential to maintain the ITER closed fuel cycle. These directly coupled diagnostic systems are an integral part of the ITER vacuum containment and are therefore subject to the same design requirements for tritium and active gas confinement, for all normal and accidental conditions. All the diagnostics, whether or not pumped, incorporate penetration of the vacuum boundary (i.e. window assembly, vacuum feedthrough etc.) and demountable joints. Monitored guard volumes are provided for all elements of the vacuum boundary that are judged to be vulnerable by virtue of their construction, material, load specification etc. Standard arrangements are made for their construction and for the monitoring, evacuating and leak testing of these volumes. Diagnostic systems are incorporated at more than 20 ports on ITER. This paper will describe typical and particular arrangements of pumped diagnostic and monitored guard volume. The status of the diagnostic vacuum systems, which are at the start of their detailed design, will be outlined and the specific features of the vacuum systems in ports and extensions

  20. Preliminary research of magnetic levitation accelerometer%磁悬浮式加速度计前期研究

    Institute of Scientific and Technical Information of China (English)

    练斌; 叶凌云; 黄添添

    2012-01-01

    为设计新型的小型高精度磁悬浮式加速度计,利用仿真软件对自制超顺磁性加速度计悬浮体在外磁场中所受的磁力进行仿真,并通过悬浮实验测试超顺磁性加速度计悬浮体在常温常压下的悬浮性能.仿真结果表明:超顺磁性加速度计悬浮体在外磁场中所受的磁力完全受外磁场控制.悬浮实验表明:当外磁场强度合适时,超顺磁性加速度计悬浮体可在常温常压下实现悬浮.实验表明:新型超顺磁性加速度计悬浮体适用于设计小型高精度磁悬浮式加速度计.%To design new type of small size high precision magnetic levitation accelerometer, the magnetic force of self-made superparamagnetic levitalion object of accelerometer in external magnetic field is simulated by software, and the levitation properties of superparamagnetic levitation object by accelerometer is test by levitation experiments. Simulation results demonstrate that the superparamagnetic leritation object of accelerometer is fully controlled by external magnetic field. Levitation experiments indicate that the superparamagnetic levitation object of accelerometer can be levitated under normal temperature and pressure. Experimental results show that this superparamagnetic levitation object of accelerometer is suitable for designing small size high precision magnetic levitation accelerometer.

  1. Iterative Reconstruction Methods for Hybrid Inverse Problems in Impedance Tomography

    DEFF Research Database (Denmark)

    Hoffmann, Kristoffer; Knudsen, Kim

    2014-01-01

    For a general formulation of hybrid inverse problems in impedance tomography the Picard and Newton iterative schemes are adapted and four iterative reconstruction algorithms are developed. The general problem formulation includes several existing hybrid imaging modalities such as current density...... impedance imaging, magnetic resonance electrical impedance tomography, and ultrasound modulated electrical impedance tomography, and the unified approach to the reconstruction problem encompasses several algorithms suggested in the literature. The four proposed algorithms are implemented numerically in two...... be based on a theoretical analysis of the underlying inverse problem....

  2. Magnetic resonance imaging spatial and time study of lung water content in newborn lamb: methods and preliminary results.

    Science.gov (United States)

    Viard, Romain; Tourneux, Pierre; Storme, Laurent; Girard, Julie-Marie; Betrouni, Nacim; Rousseau, Jean

    2008-06-01

    To study the lung liquid clearance in vivo at the time of birth, magnetic resonance experiments were conducted on newborn lambs immediately after uterine incision deliverance. Images obtained with a fast spin echo magnetic resonance imaging sequence enable to quantify lung liquid each 5 minutes for 30 minutes, then each 10 minutes for 1.5 hours. After manually determining lung contours, pulmonary volume, pulmonary water, and spatial gradient of pulmonary water were studied. At 2 hours of life, the total pulmonary water content was still high and the liquid clearance was slower in the lower part of the lung. Air inflation increased the size of the distal airways and shifted liquid from the lung lumen towards the pulmonary interstitial tissue. The lung liquid washout was belated, and the passage to the aerial life was performed by progressive liberation of the superior pulmonary spaces, water flowing out by gravity toward the lower spaces.

  3. Preliminary Observations on Sensitivity and Specificity of Magnetization Transfer Asymmetry for Imaging Myelin of Rat Brain at High Field.

    Science.gov (United States)

    Kim, Jae-Woong; Choi, Jiye; Cho, Janggeun; Lee, Chulhyun; Jeon, Daejong; Park, Sung-Hong

    2015-01-01

    Magnetization transfer ratio (MTR) has been often used for imaging myelination. Despite its high sensitivity, the specificity of MTR to myelination is not high because tissues with no myelin such as muscle can also show high MTR. In this study, we propose a new magnetization transfer (MT) indicator, MT asymmetry (MTA), as a new method of myelin imaging. The experiments were performed on rat brain at 9.4 T. MTA revealed high signals in white matter and significantly low signals in gray matter and muscle, indicating that MTA has higher specificity than MTR. Demyelination and remyelination studies demonstrated that the sensitivity of MTA to myelination was as high as that of MTR. These experimental results indicate that MTA can be a good biomarker for imaging myelination. In addition, MTA images can be efficiently acquired with an interslice MTA method, which may accelerate clinical application of myelin imaging.

  4. Magnetic polarity ages of the fossil-bearing strata at the Si hetun section, West Liaoning:A preliminary result

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Rock-magnetic and palaeomagnetic studies have been carried out on the interval of famous fossil-bearing sedimentary rocks and its overlying basalts and underlying basalts at the Sihetun section, West Liaoning Province. Normal polarity was obtained for the sedimentary interval and the underlying basalts, while reversed polarity was found in the overlying basalts. Taking account of the new 40Ar/39Ar ages (Swisher et al., 1999), we classified the fossil-bearing sedimentary interval into the Barremian M3n zone (Early Cretaceous age). Several abnormal horizons on magnetic properties, probably corresponding to the tuffs,were observed in the fossil-bearing sedimentary interval.This implies that the massive bio-extinction may link to dramatic environmental changes that were caused by voleanic eruptions.``

  5. Intracerebral hemorrhage (ICH) evaluation with a novel magnetic induction sensor: a preliminary study using the Chinese head model.

    Science.gov (United States)

    Zhang, Ziyi; Liu, Peiguo; Zhou, Dongming; Zhang, Liang; Lei, Hengdong

    2014-01-01

    Biomedical magnetic induction measurement is a promising method for the detection of intracerebral hemorrhage (ICH), especially in China. Aiming at overcoming the problem of low sensitivity, a magnetic induction sensor is chosen to replace the conventional sensors. It uses a two-arm Archimedean spiral coil as the exciter and a circular coil as the receiver. In order to carry out high-fidelity simulations, the Chinese head model with real anatomical structure is introduced into this novel sensor for the first time. Simulations have been carried out upon early stage ICH measurements. By calculating the state sensitivity and time sensitivity of the perturbation phase of two types of sensors using the electromagnetic software, we conclude that the primary signal received can be largely reduced using the novel sensor, which could effectively increase the time and state sensitivity simultaneously.

  6. Preliminary results from the first integrated Magnetized Liner Inertial Fusion (MagLIF) experiments on the Z accelerator

    Science.gov (United States)

    Gomez, M. R.; Slutz, S. A.; Sefkow, A. B.; Harvey-Thompson, A. J.; Awe, T. J.; Cuneo, M. E.; Geissel, M.; Herrmann, M.; Jennings, C.; Lamppa, D.; Martin, M.; McBride, R. D.; Rovang, D. C.; Sinars, D.; Smith, I. C.

    2013-10-01

    Sandia National Laboratories' Z Machine provides a drive current of up to 27 MA with 100 ns risetime to a magnetically-driven load. Magnetized Liner Inertial Fusion (MagLIF) is the main focus of the inertial confinement fusion program on Z. The MagLIF concept uses an imploding metallic cylindrical liner to compress magnetized, pre-heated fusion fuel. Simulations indicate that fusion yields on the order of 100 kJ (5e16 DT neutrons) are achievable with a drive current of 27 MA in 100 ns, a laser preheat of 8 kJ in 8 ns, an applied axial B-field of 30 T, and deuterium-tritium fusion fuel. The first fully integrated MagLIF experiments are scheduled to be conducted on Z late summer 2013. These tests will utilize a drive current of 16 MA, a laser preheat of 2 kJ in 2 ns, an applied B-field of 10 T, and deuterium fuel. With these reduced parameters, simulations predict yields greater than 1e10 DD neutrons. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. MAGNET

    CERN Multimedia

    by B. Curé

    2011-01-01

    The magnet operation was very satisfactory till the technical stop at the end of the year 2010. The field was ramped down on 5th December 2010, following the successful regeneration test of the turbine filters at full field on 3rd December 2010. This will limit in the future the quantity of magnet cycles, as it is no longer necessary to ramp down the magnet for this type of intervention. This is made possible by the use of the spare liquid Helium volume to cool the magnet while turbines 1 and 2 are stopped, leaving only the third turbine in operation. This obviously requires full availability of the operators to supervise the operation, as it is not automated. The cryogenics was stopped on 6th December 2010 and the magnet was left without cooling until 18th January 2011, when the cryoplant operation resumed. The magnet temperature reached 93 K. The maintenance of the vacuum pumping was done immediately after the magnet stop, when the magnet was still at very low temperature. Only the vacuum pumping of the ma...

  8. A recursion identity for formal iterated logarithms and iterated exponentials

    CERN Document Server

    Robinson, Thomas J

    2010-01-01

    We prove a recursive identity involving formal iterated logarithms and formal iterated exponentials. These iterated logarithms and exponentials appear in a natural extension of the logarithmic formal calculus used in the study of logarithmic intertwining operators and logarithmic tensor category theory for modules for a vertex operator algebra. This extension has a variety of interesting arithmetic properties. We develop one such result here, the aforementioned recursive identity. We have applied this identity elsewhere to certain formal series expansions related to a general formal Taylor theorem and these series expansions in turn yield a sequence of combinatorial identities which have as special cases certain classical combinatorial identities involving (separately) the Stirling numbers of the first and second kinds.

  9. Geothermal Potential of the Siǧacik Gulf (Seferihisar) and Preliminary investigations with Seismic and Magnetic Surveys

    Science.gov (United States)

    Bakak, Özde; Özel, Erdeniz; Ergün, Mustafa

    2015-04-01

    The Aegean region, including both W. Turkey and Central Greece, is one of the world's most rapidly-deforming regions of continental crust and has a seismic rate is exceptional on a world scale. SW Turkey is one of the most rapidly extending regions in the world where the extension appears to have commenced in middle or late Miocene time. Paleomagnetic work in W Turkey and Aegean islands has revealed the horizontal rotation of some crustal blocks. In W Turkey clockwise rotation on Karaburun peninsula west of Izmir by 44° in the last few Ma is detected, and anticlockwise rotation of 37° for the Seferihisar region. The area of W Turkey and the Aegean islands has very strong geothermal gradient in the world scale. Sığacık Gulf is located on south of Karaburun Peninsula, and it is restricted by two important ridges as Karaburun and Seferihisar Ridges. Recent geological and geophysical studies suggested that this area is both E-W trending normal and NE-SW trending strike-slip faulting caused deformation. The Seferihisar earthquake series were occurred here during 17-20 October 2005. For investigation of geothermal potential and hot water outlets on the seafloor, shallow seismic and magnetic surveys are preferred, which were carried out onboard Dokuz Eylül-1 vessel belongs to Dokuz Eylül University, in 2011. Approximately 250km seismic reflection data was collected along 27 lines. During seismic method used Sparker system which has 1 channel and 12 hydrophone with 17 m long streamer, as a seismic source used SIG Seismic Marine ELC 80 (4 kV & 3.2 KV DC). Seismic data processing (band pass filter, bottom mute, top mute, true amplitude recovery, time migration) was made using Promax program in the Seismic Laboratory in the Institute of Marine Science and Technology. The basement topography map was prepared using Kingdom Suite program drawing seabed line on these sections. Sea floor topography changes between 30-120 m, and this increases towards Ikaria Basin

  10. Characterization of prostate cancer, benign prostatic hyperplasia and normal prostates using transrectal 31phosphorus magnetic resonance spectroscopy: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, P.; Jajodia, P.; Kurhanewicz, J.; Thomas, A.; MacDonald, J.; Hubesch, B.; Hedgcock, M.; Anderson, C.M.; James, T.L.; Tanagho, E.A. (Univ. of California School of Medicine, San Francisco (USA))

    1991-07-01

    We assessed the ability of 31phosphorus (31P) transrectal magnetic resonance spectroscopy to characterize normal human prostates as well as prostates with benign and malignant neoplasms. With a transrectal probe that we devised for surface coil spectroscopy we studied 15 individuals with normal (5), benign hyperplastic (4) and malignant (6) prostates. Digital rectal examination, transrectal ultrasonography and magnetic resonance imaging were used to aid in accurate positioning of the transrectal probe against the region of interest within the prostate. The major findings of the in vivo studies were that normal prostates had phosphocreatine-to-adenosine triphosphate (ATP) ratios of 1.2 +/- 0.2, phosphomonoester-to-beta-ATP ratios of 1.1 +/- 0.1 and phosphomonoester-to-phosphocreatine ratios of 0.9 +/- 0.1. Malignant prostates had phosphocreatine-to-beta-ATP ratios that were lower (0.7 +/- 0.1) than those of normal prostates (p less than 0.02) or prostates with benign hyperplasia. Malignant prostates had phosphomonoester-to-beta-ATP ratios (1.8 +/- 0.2) that were higher than that of normal prostates (p less than 0.02). Using the phosphomonoester-to-phosphocreatine ratio, it was possible to differentiate metabolically malignant (2.7 +/- 0.3) from normal prostates (p less than 0.001), with no overlap of individual ratios. The mean phosphomonoester-to-phosphocreatine ratio (1.5 +/- 0.5) of prostates with benign hyperplasia was midway between the normal and malignant ratios, and there was overlap between individual phosphomonoester-to-phosphocreatine ratios of benign prostatic hyperplasia glands with that of normal and malignant glands. To verify the in vivo results, we performed high resolution magnetic resonance spectroscopy on perchloric acid extracts of benign prostatic hyperplasia tissue obtained at operation and on a human prostatic cancer cell line DU145.

  11. Development and preliminary validation of the spondyloarthritis research consortium of Canada magnetic resonance imaging sacroiliac joint structural score

    DEFF Research Database (Denmark)

    Maksymowych, Walter P; Wichuk, Stephanie; Chiowchanwisawakit, Praveena

    2015-01-01

    on magnetic resonance imaging (MRI), the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ Structural Score (SSS). METHODS: The SSS method for assessment of structural lesions is based on T1-weighted spin echo MRI, validated lesion definitions, slice selection according to well-defined anatomical...... in scores, and was highest for fat metaplasia when both ICC and SDC values were compared. CONCLUSION: The new SPARCC MRI SSS method can detect structural changes in the SIJ with acceptable reliability over a 1-2-year timeframe, and should be further validated in patients with SpA....

  12. Design of ITER vacuum vessel in-wall shielding

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X., E-mail: xiaoyu.wang@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Ioki, K. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Morimoto, M. [Mitsubishi Heavy Industries, 1-1, Wadasaki-cho 1-chome, Hyogo-ku, Kobe (Japan); Choi, C.H.; Utin, Y.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); TaiLhardat, O. [Assystem EOS, ZAC SAINT MARTIN, 23 rue Benjamin Franklin, 84120 Pertuis (France); Mille, B.; Terasawa, A.; Gribov, Y.; Barabash, V.; Polunovskiy, E.; Dani, S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Pathak, H.; Raval, J. [ITER-India, Institute for Plasma Research, Gandhinagar 382025 (India); Liu, S.; Lu, M.; Du, S. [Institute of Plasma Physics, China Academy of Sciences, Shushanhu Road 350, Hefei (China)

    2014-10-15

    The ITER vacuum vessel is a torus-shaped, double wall structure. The space between the double walls of the VV is filled with in-wall shielding (IWS) and cooling water. The main purpose of the in-wall shielding is to provide neutron shielding together with the blanket and VV shells and water during ITER plasma operation and to reduce the ripple of the Toroidal magnetic field. Based on ITER vacuum vessel structure and related requirements, in-wall shielding are designed as about 8900 individual blocks with different sizes and several different materials distributed over nine vessel sectors and nine field joints of vessel sectors. This paper presents the design of the IWS, considering loads, structural stresses and assembly method, and also shows neutron shielding effect and TF ripple reduced by the IWS.

  13. Relaxation Criteria for Iterated Traffic Simulations

    Science.gov (United States)

    Kelly, Terence; Nagel, Kai

    Iterative transportation microsimulations adjust traveler route plans by iterating between a microsimulation and a route planner. At each iteration, the route planner adjusts individuals' route choices based on the preceding microsimulations. Empirically, this process yields good results, but it is usually unclear when to stop the iterative process when modeling real-world traffic. This paper investigates several criteria to judge relaxation of the iterative process, emphasizing criteria related to traveler decision-making.

  14. A Web-based searchable system to confirm magnetic resonance compatibility of implantable medical devices in Japan: a preliminary study.

    Science.gov (United States)

    Fujiwara, Yasuhiro; Fujioka, Hitoshi; Watanabe, Tomoko; Sekiguchi, Maiko; Murakami, Ryuji

    2017-07-31

    Confirmation of the magnetic resonance (MR) compatibility of implanted medical devices (IMDs) is mandatory before conducting magnetic resonance imaging (MRI) examinations. In Japan, few such confirmation methods are in use, and they are time-consuming. This study aimed to develop a Web-based searchable MR safety information system to confirm IMD compatibility and to evaluate the usefulness of the system. First, MR safety information for intravascular stents and stent grafts sold in Japan was gathered by interviewing 20 manufacturers. These IMDs were categorized based on the descriptions available on medical package inserts as: "MR Safe," "MR Conditional," "MR Unsafe," "Unknown," and "No Medical Package Insert Available". An MR safety information database for implants was created based on previously proposed item lists. Finally, a Web-based searchable system was developed using this database. A questionnaire was given to health-care personnel in Japan to evaluate the usefulness of this system. Seventy-nine datasets were collected using information provided by 12 manufacturers and by investigating the medical packaging of the IMDs. Although the datasets must be updated by collecting data from other manufacturers, this system facilitates the easy and rapid acquisition of MR safety information for IMDs, thereby improving the safety of MRI examinations.

  15. Liver stiffness measured by magnetic resonance elastography as a risk factor for hepatocellular carcinoma: a preliminary case-control study

    Energy Technology Data Exchange (ETDEWEB)

    Motosugi, Utaroh; Ichikawa, Tomoaki; Koshiishi, Tsuyota; Sano, Katsuhiro; Morisaka, Hiroyuki; Ichikawa, Shintaro; Araki, Tsutomu [University of Yamanashi, Department of Radiology, Yamanashi-ken (Japan); Enomoto, Nobuyuki [University of Yamanashi, 1st Department of Internal Medicine, Yamanashi (Japan); Matsuda, Masanori; Fujii, Hideki [University of Yamanashi, 1st Department of Surgery, Yamanashi (Japan)

    2013-01-15

    To examine if liver stiffness measured by magnetic resonance elastography (MRE) is a risk factor for hepatocellular carcinoma (HCC) in patients with chronic liver disease. By reviewing the records of magnetic resonance (MR) examinations performed at our institution, we selected 301 patients with chronic liver disease who did not have a previous medical history of HCC. All patients underwent MRE and gadoxetic acid-enhanced MR imaging. HCC was identified on MR images in 66 of the 301 patients, who were matched to controls from the remaining patients without HCC according to age. MRE images were obtained by visualising elastic waves generated in the liver by pneumatic vibration transferred via a cylindrical passive driver. Risk factors of HCC development were determined by the odds ratio with logistic regression analysis; gender and liver stiffness by MRE and serum levels of aspartate transferase, alanine transferase, alpha-fetoprotein, and protein induced by vitamin K absence-II. Multivariate analysis revealed that only liver stiffness by MRE was a significant risk factor for HCC with an odds ratio (95 % confidence interval) of 1.38 (1.05-1.84). Liver stiffness measured by MRE is an independent risk factor for HCC in patients with chronic liver disease. (orig.)

  16. Preliminary guidelines for safe and effective use of repetitive transcranial magnetic stimulation in moderate to severe traumatic brain injury.

    Science.gov (United States)

    Nielson, Dylan M; McKnight, Curtis A; Patel, Riddhi N; Kalnin, Andrew J; Mysiw, Walter J

    2015-04-01

    Transcranial magnetic stimulation has generated extensive interest within the traumatic brain injury (TBI) rehabilitation community, but little work has been done with repetitive protocols, which can produce prolonged changes in behavior. This is partly because of concerns about the safety of repetitive transcranial magnetic stimulation (rTMS) in subjects with TBI, particularly the risk of seizures. These risks can be minimized by careful selection of the rTMS protocol and exclusion criteria. In this article, we identify guidelines for safe use of rTMS in subjects with TBI based on a review of the literature and illustrate their application with a case study. Our subject is a 48-year-old man who sustained a severe TBI 5 years prior to beginning rTMS for the treatment of post-TBI depression. After a 4-week baseline period, we administered daily sessions of low-frequency stimulation to the right dorsolateral prefrontal cortex for 6 weeks. After stimulation, we performed monthly assessments for 3 months. The Hamilton Depression Rating Scale (HAMD) was our primary outcome measure. The stimulation was well tolerated and the patient reported no side effects. After 6 weeks of stimulation, the patient's depression was slightly improved, and these improvements continued through follow-up. At the end of follow-up, the patient's HAMD score was 49% of the average baseline score.

  17. The ITER Radial Neutron Camera Detection System

    Science.gov (United States)

    Marocco, D.; Belli, F.; Bonheure, G.; Esposito, B.; Kaschuck, Y.; Petrizzi, L.; Riva, M.

    2008-03-01

    A multichannel neutron detection system (Radial Neutron Camera, RNC) will be installed on the ITER equatorial port plug 1 for total neutron source strength, neutron emissivity/ion temperature profiles and nt/nd ratio measurements [1]. The system is composed by two fan shaped collimating structures: an ex-vessel structure, looking at the plasma core, containing tree sets of 12 collimators (each set lying on a different toroidal plane), and an in-vessel structure, containing 9 collimators, for plasma edge coverage. The RNC detecting system will work in a harsh environment (neutron fiux up to 108-109 n/cm2 s, magnetic field >0.5 T or in-vessel detectors), should provide both counting and spectrometric information and should be flexible enough to cover the high neutron flux dynamic range expected during the different ITER operation phases. ENEA has been involved in several activities related to RNC design and optimization [2,3]. In the present paper the up-to-date design and the neutron emissivity reconstruction capabilities of the RNC will be described. Different options for detectors suitable for spectrometry and counting (e.g. scintillators and diamonds) focusing on the implications in terms of overall RNC performance will be discussed. The increase of the RNC capabilities offered by the use of new digital data acquisition systems will be also addressed.

  18. A Linear Iterative Unfolding Method

    CERN Document Server

    Laszlo, Andras

    2011-01-01

    A frequently faced task in experimental physics is to measure the probability distribution of some quantity. Often this quantity to be measured is smeared by a non-ideal detector response or by some physical process. The procedure of removing this smearing effect from the measured distribution is called unfolding, and is a delicate problem in signal processing. Due to the numerical ill-posedness of this task, various methods were invented which, given some assumptions on the initial probability distribution, try to regularize the problem. Most of these methods definitely introduce bias on the estimate of the initial probability distribution. We propose a linear iterative method (motivated by the Neumann series / Landweber iteration known in functional analysis), which has the advantage that no assumptions on the initial probability distribution is needed, and the only regularization parameter is the stopping order of the iteration. Convergence is proved under certain quite general conditions, which hold for p...

  19. Construction Safety Forecast for ITER

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Conceptual design study of the K-DEMO magnet system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Keeman, E-mail: kkeeman@nfri.re.kr [National Fusion Research Institute, 169-148 Gwahak-ro, Daejeon 305-806 (Korea, Republic of); Oh, Sangjun; Park, Jong Sung; Lee, Chulhee; Im, Kihak; Kim, Hyung Chan; Lee, Gyung-Su [National Fusion Research Institute, 169-148 Gwahak-ro, Daejeon 305-806 (Korea, Republic of); Neilson, George; Brown, Thomas; Kessel, Charles; Titus, Peter; Zhai, Yuhu [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

    2015-10-15

    Highlights: • Perform a preliminary conceptual study for a steady-state Korean DEMO reactor. • Present a preliminary design of TF (toroidal field) magnet. • Present a preliminary design of CS (central solenoid) magnet. • Present a preliminary design of PF (toroidal field) magnet. - Abstract: As the ITER is being constructed, there is a growing anticipation for an earlier realization of fusion energy. A major design philosophy for the initiated conceptual design study for a steady-state Korean fusion demonstration reactor (K-DEMO) is engineering feasibility. A two-staged development plan is envisaged. K-DEMO is designed not only to demonstrate a net electricity generation and a self-sustained tritium cycle, but also to be used, in its initial stage, as a component test facility. Then, in its second stage, a major upgrade is carried out by replacing in-vessel components in order to show a net electricity generation on the order of 500 MWe. After a thorough 0-D system analysis, the major radius and minor radius are chosen to be 6.8 m and 2.1 m, respectively. In order to minimize wave deflection, a top-launch high frequency (>200 GHz) electron cyclotron current drive (ECCD) system will be the key system for the current profile control. For matching the high frequency ECCD, a high toroidal field (TF) is required and can be achieved by using high current density Nb{sub 3}Sn superconducting conductor. The peak magnetic field reaches to 16 T with the magnetic field at the plasma center above 7 T. Key features of the K-DEMO magnet system include the use of two TF coil winding packs, each of a different conductor design, to reduce the construction cost and save the space for the magnet structure material.

  1. EC power management and NTM control in ITER

    Science.gov (United States)

    Poli, Francesca; Fredrickson, E.; Henderson, M.; Bertelli, N.; Farina, D.; Figini, L.; Nowak, S.; Poli, E.; Sauter, O.

    2016-10-01

    The suppression of Neoclassical Tearing Modes (NTMs) is an essential requirement for the achievement of the demonstration baseline in ITER. The Electron Cyclotron upper launcher is specifically designed to provide highly localized heating and current drive for NTM stabilization. In order to assess the power management for shared applications, we have performed time-dependent simulations for ITER scenarios covering operation from half to full field. The free-boundary TRANSP simulations evolve the magnetic equilibrium and the pressure profiles in response to the heating and current drive sources and are interfaced with a GRE for the evolution of size and frequency of the magnetic islands. Combined with a feedback control of the EC power and the steering angle, these simulations are used to model the plasma response to NTM control, accounting for the misalignment of the EC deposition with the resonant surfaces, uncertainties in the magnetic equilibrium reconstruction and in the magnetic island detection threshold. Simulations indicate that the threshold for detection of the island should not exceed 2-3cm, that pre-emptive control is a preferable option, and that for safe operation the power needed for NTM control should be reserved, rather than shared with other applications. Work supported by ITER under IO/RFQ/13/9550/JTR and by DOE under DE-AC02-09CH11466.

  2. Progress on the ITER TBM port plug design

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung-Yoon, E-mail: byoungyoon.kim@iter.org [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Marconi, Matteo [LTCalcoli, Piazza Prinetti 26/B, 23807 Merate (Italy); Neviere, Jean-Christophe [Comex Nucléaire, 13115 Saint Paul Lez Durance (France); Merola, Mario; Giancarli, Luciano M. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Lucca, Flavio [LTCalcoli, Piazza Prinetti 26/B, 23807 Merate (Italy); Gicquel, Stefan [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2015-10-15

    Highlights: • ITER TBM PP design progress with two Dummy TBMs was outlined. • Attachment of Dummy TBMs in TBM Frame was assessed to investigate mechanical and sealing performance. • Implementation of cover plates was described and the preliminary maintenance sequence was developed. • Clearance between TBM Frame and Dummy TBMs were reduced to have better shielding performance. • Cooling layout and castellation design were updated to minimize thermal induced stress. - Abstract: In three of the ITER equatorial ports, tritium breeding blanket concepts will be validated and tested using mock-up breeding blankets called test blanket modules (TBM). In these ports, two TBM-Sets are mechanically attached in a TBM Frame to form a TBM port plug (TBM PP). The ITER Organization is responsible for the design and manufacture of both this TBM Frame and the Dummy TBMs which will fill them. As a part of this development, in 2013, a conceptual design review (CDR) of TBM PP with two dummy TBMs revealed the need for improvement of design performance, interfaces and maintainability. This paper presents the main design improvements after the CDR as well as associated feasibility analysis of the improved design focusing on the attachment. Finally the work plan for the Preliminary Design phase is summarized.

  3. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet was energised at the beginning of March 2012 at a low current to check all the MSS safety chains. Then the magnet was ramped up to 3.8 T on 6 March 2012. Unfortunately two days later an unintentional switch OFF of the power converter caused a slow dump. This was due to a misunderstanding of the CCC (CERN Control Centre) concerning the procedure to apply for the CMS converter control according to the beam-mode status at that time. Following this event, the third one since 2009, a discussion was initiated to define possible improvement, not only on software and procedures in the CCC, but also to evaluate the possibility to upgrade the CMS hardware to prevent such discharge from occurring because of incorrect procedure implementations. The magnet operation itself was smooth, and no power cuts took place. As a result, the number of magnetic cycles was reduced to the minimum, with only two full magnetic cycles from 0 T to 3.8 T. Nevertheless the magnet suffered four stops of the cryogeni...

  4. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    Operation of the magnet has gone quite smoothly during the first half of this year. The magnet has been at 4.5K for the full period since January. There was an unplanned short stop due to the CERN-wide power outage on May 28th, which caused a slow dump of the magnet. Since this occurred just before a planned technical stop of the LHC, during which access in the experimental cavern was authorized, it was decided to leave the magnet OFF until 2nd June, when magnet was ramped up again to 3.8T. The magnet system experienced a fault also resulting in a slow dump on April 14th. This was triggered by a thermostat on a filter choke in the 20kA DC power converter. The threshold of this thermostat is 65°C. However, no variation in the water-cooling flow rate or temperature was observed. Vibration may have been the root cause of the fault. All the thermostats have been checked, together with the cables, connectors and the read out card. The tightening of the inductance fixations has also been checked. More tem...

  5. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      Following the unexpected magnet stops last August due to sequences of unfortunate events on the services and cryogenics [see CMS internal report], a few more events and initiatives again disrupted the magnet operation. All the magnet parameters stayed at their nominal values during this period without any fault or alarm on the magnet control and safety systems. The magnet was stopped for the September technical stop to allow interventions in the experimental cavern on the detector services. On 1 October, to prepare the transfer of the liquid nitrogen tank on its new location, several control cables had to be removed. One cable was cut mistakenly, causing a digital input card to switch off, resulting in a cold-box (CB) stop. This tank is used for the pre-cooling of the magnet from room temperature down to 80 K, and for this reason it is controlled through the cryogenics control system. Since the connection of the CB was only allowed for a field below 2 T to avoid the risk of triggering a fast d...

  6. Rollout Sampling Approximate Policy Iteration

    CERN Document Server

    Dimitrakakis, Christos

    2008-01-01

    Several researchers have recently investigated the connection between reinforcement learning and classification. We are motivated by proposals of approximate policy iteration schemes without value functions which focus on policy representation using classifiers and address policy learning as a supervised learning problem. This paper proposes variants of an improved policy iteration scheme which addresses the core sampling problem in evaluating a policy through simulation as a multi-armed bandit machine. The resulting algorithm offers comparable performance to the previous algorithm achieved, however, with significantly less computational effort. An order of magnitude improvement is demonstrated experimentally in two standard reinforcement learning domains: inverted pendulum and mountain-car.

  7. Quantitative magnetic resonance methods for in vivo investigation of the human liver and spleen. Technical aspects and preliminary clinical results

    DEFF Research Database (Denmark)

    Thomsen, C

    1996-01-01

    This project was initiated with the introduction of magnetic resonance (MR) in Denmark in order to evaluate the possibilities of this technique as a diagnostic aid in non-focal liver and splenic diseases. The signal intensities in the MR image are sensitive to the longitudinal relaxation (T1...... sequences with different repetition times was chosen, because motion effects were partly refocused. Multi-acquisition was used to improve the signal-to-noise ratio in the heavily saturated experiments with short repetition times, to further reduce the sensitivity to motion. To test the quality of this pulse...... sequence, phantom experiments were performed, and sensitivity to motion was tested by measuring with and without respiratory synchronization. Respiratory synchronization gave a marked improvement in focal liver diseases, whereas no difference was found in non-focal diseases. Standard imaging sequences...

  8. A Preliminary Application of Magnetic Resonance Spectroscopy for Quantitatively Assessing Hepatic Fat and the Efficacy of Anti-obesity Therapy

    Directory of Open Access Journals (Sweden)

    Hyunseung Lee

    2010-11-01

    Full Text Available Alcoholic and non-alcoholic fatty liver diseases cause insulin resistance and may develop into metabolic diseases such as steatohepatitis or type II diabetes. Standard histopathological examinations are routinely used to measure hepatic fat in order to assess and treat liver diseases, but this method is invasive, complicated, and time-consuming. Here, we present a noninvasive technique, localized magnetic resonance spectroscopy (MRS, for quantitatively measuring hepatic fat in vivo and in situ. This method allowed us to create a relatively high-resolution time series from the same mouse. Further, it enabled us to examine the efficacy of cryptotanshinone (Ct treatment in male mice with non-alcoholic fatty liver disease; MRS clearly showed that mice treated with Ct experienced a dramatic reduction in hepatic fat content compared with control mice. Thus, the localized MRS technique shows promise as a tool for in vivo assessments of drug efficacy against liver fat diseases and for early-stage disease prevention

  9. Quality by Design approach in the development of a magnetic transducer for biomedical measurements: preliminary results on Design Space configuration

    Science.gov (United States)

    Louzada, D. R.; Monteiro, E. C.; Rivero, A. M.; Fortaleza, L. G. S.; Barbosa, C. R. H.; Velázquez, D. R. T.; Silva, E. C.; Gusmão, L. A. P.

    2016-11-01

    The concept of Quality by Design (QbD) has been widely used by the pharmaceutical industry since 2004, changing the focus on inspections to embrace greater control in the manufacturing process. This new approach contributed to lower production costs and higher quality of medicines. This work discusses the first steps towards the implementation of a QbD approach aimed at ensuring the quality of a biomedical device under development. This device will be applied as a non-magnetic metallic foreign body localization system for surgical removal guidance. It should be highlighted that a new approach was used to define the Design Space, based on fuzzy logic rather than the typical statistical techniques.

  10. Use of magnetic hysteresis properties and electron spin resonance spectroscopy for the identification of volcanic ash: a preliminary study

    Science.gov (United States)

    Pawse, Archana; Beske-Diehl, Suzanne; Marshall, S. A.

    1998-03-01

    This initial study investigates the possible use of hysteresis parameters and electron spin resonance (ESR) spectroscopy to identify and correlate volcanic ash. ESR and hysteresis properties are sensitive to characteristics such as the chemical composition, mineralogy, and grain size and shape. These characteristics are determined by the tectonic setting of the volcano and by the magmatic and eruptive history of the volcanic ash. Hysteresis properties and ESR spectra, therefore, should be distinct for each ash eruption and may help to identify the eruptive source of the ash and to correlate ash from unknown sources. We conducted ESR spectroscopy at room temperature and magnetic hysteresis measurements on 19 samples of a single ash, the 1974 October 14 eruption of the Fuego volcano, Guatemala, and on single samples of ash obtained from eight different volcanoes. The Fuego ash samples were obtained at increasing distances from the volcano. For the single Fuego ash, ESR spectra and hysteresis parameters become increasingly similar as the distance from the volcano increases. At distances greater than 30km, ESR spectra and hysteresis properties are uniform. The variability of magnetic and ESR properties with distance from Fuego is due to the preferential fall-out of phenocrysts closer to the volcano. At large distances, the ash is more uniform, containing more glass and microcrystals. All eight ash samples from the different volcanoes can be distinguished from the distal Fuego 1974 October 14 ash using ESR spectra and hysteresis parameters. These results suggest that ESR and hysteresis measurements have a potential to be used as tools to identify distal ash when used in conjunction with geochemical, mineralogical and/or other types of data.

  11. Project status of manufacturing of European toroidal coils ITER. Validation tests; Estado del proyecto de fabricacion de las bobinas toroidales european para el ITER. Ensayos de validacion

    Energy Technology Data Exchange (ETDEWEB)

    Pando, F.; Felipe, A.; Madorran, A.; Pallisa, J.; Dormicch, O.; Valle, N.; D' Urzo, C.; Marin, M.; Pesenti, P.; Lucas, J.; Moreno, N.; Bonito-Oliva, A.; Harrison, R.; Bellesia, B.; Cornelis, M.; Cornella, J.

    2015-07-01

    The toroidal field coils are the ITER magnets responsible for confining the plasma inside the vacuum vessel. The consortium formed by IBERDROLA Ingenieria y Construccion, ASG Superconductors y ELYTT Energy is the responsible for the supply of 10 coils that the european agency F4E has to supply for the ITER project. At present, the coils are been manufactured in La Spezia (Italy), after the qualification of all the manufacturing process and the sucessfull manufacturing of a full scale prototype. (Author)

  12. Dusts in ITER: diagnostics and removal techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rosanvallon, S.; Grisolia, C.; Worms, J.; Hong, S.H. [Association Euratom-CEA Cadarache (DRFC/SIPP), 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Delaporte, P. [Universite de la Mediterranee, LP3, UMR 6182 CNRS, 13 - Marseille (France); Onofrie, J.F. [University of Provence, IUSTI-CNRS, 13 - Marseille (France); Counsell, G. [Association Euratom/UKAEA, Culham Science Centre, Abingdon (United Kingdom); Winter, J. [lnstitute of Experimental Physics 2, Bochum (Germany)

    2007-07-01

    Full text of publication follows: Dusts will be present in ITER and will represent an issue in terms of safety. As a matter of facts, dusts will be created by interaction of the plasma with the in-vessel materials and will be thus made of carbon, beryllium and tungsten. They will be activated, tritiated and chemically toxic. Safety limits have been set in order to reduce these dust hazards. The first set of limits is based on a limitation of the radiological impact on environment in case of dust spreading. Tungsten has been used as representative of ITER dust because it is the most radiologically hazardous of the plasma facing materials. Thus the mobilizable dust inside the vacuum vessel has to be limited to few hundreds of kilograms of carbon, beryllium and tungsten. The objective of the second set of limits is to ensure that the dust chemical reactivity is adequately controlled. Indeed this reactivity is greatly enhanced on the hot surfaces of the divertor in case of steam ingress, oxidation of the metals, beryllium in particular, leading to hydrogen production and possible explosion. The dusts on the hot surfaces of the divertor should not exceed few kilograms of carbon, beryllium and tungsten. Some calculations have shown that the dusts limits inside the vacuum vessel could be reached in about 500 plasma pulses, and in any case before the assumed replacement of the divertor for planned maintenance. Thus techniques for dust diagnostics and removal need to be developed for ITER to ensure that the set of safety limits are fulfilled. To minimize the impact on the machine operation time, these techniques have to be elaborated considering the ITER vacuum vessel constraints if entering the machine (magnetic field, radiation, vacuum and temperature) or to be non invasive. This paper will present a strategy that could be developed at different periods of the machine operation (during/between pulses and during short or long maintenance periods) in order to monitor the

  13. The JET technology program in support of ITER

    Energy Technology Data Exchange (ETDEWEB)

    Batistoni, P., E-mail: paola.batistoni@jet.efda.org [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Associazione EURATOM ENEA sulla Fusione, Via E. Fermi 45, I-00044 Frascati (Rome) (Italy); Likonen, J. [Association EURATOM-TEKES, VTT, PO Box 1000, 02044 VTT Espoo (Finland); Bekris, N. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Brezinsek, S. [Association EURATOM-Forschungszentrum Jülich, IPP, D-52425 Jülich (Germany); Coad, P. [EURATOM CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Horton, L. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Matthews, G. [EURATOM CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Rubel, M. [Royal Institute of Technology, Association EURATOM-VR, 100 44 Stockholm (Sweden); Sips, G. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Syme, B.; Widdowson, A. [EURATOM CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2014-10-15

    This paper presents an overview of the current and planned technological activities at JET in support of ITER operation and safety. The scope is very broad and it ranges from analysis of components from the ITER-like Wall (ILW) to determine material erosion and deposition, dust generation and fuel retention to neutronics measurements and analyses. Preliminary results are given of the post-mortem analyses of samples exposed to JET plasmas during the first JET-ILW operation in 2011–2012, and retrieved during the following in-vessel intervention. JET is the only fusion machine capable of producing significant neutron yields, up to nearly 10{sup 19} n/s (14.1 MeV) in DT operations. Recently, the technological potential of a new DT campaign at JET in support of ITER has been explored and the outcome of this assessment is presented. The expected 14 MeV neutron yield, the use of tritium, the preparation and implementation of safety measures will provide a unique occasion to gain experience in several ITER relevant technological areas. A number of projects and experiments to be conducted in conjunction with the DT operation have been identified and they are described in this paper.

  14. Lensless microscope based on iterative in-line holographic reconstruction

    Science.gov (United States)

    Wu, Jigang

    2014-11-01

    We propose a lensless microscopic imaging technique based on iteration algorithm with known constraint for image reconstruction in digital in-line holography. In our method, we introduce a constraint on the sample plane as known part in the lensless microscopy for iteration algorithm in order to eliminate the twin-image effect of holography and thus lead to better performance on microscopic imaging. We evaluate our method by numerical simulation and built a prototype in-line holographic imaging system and demonstrated its capability by preliminary experiments. In our proposed setup, a carefully designed photomask used to hold the sample is under illumination of a coherent light source. The in-line hologram is then recorded by a CMOS sensor. In the reconstruction, the known information of the illumination beam and the photomask is used as constraints in the iteration process. The improvement of image quality because of suppression of twin-images can be clearly seen by comparing the images obtained by direct holographic reconstruction and our iterative method.

  15. Value Engineering in System of Cryoline and Cryo- distribution for ITER: In-kind Contribution from India

    Science.gov (United States)

    Sarkar, B.; Shah, N.; Vaghela, H.; Bhattacharya, R.; Choukekar, K.; Patel, P.; Chang, H.-S.; Badgujar, S.; Chalifour, M.

    2015-12-01

    System of Cryoline and Cryo-distribution for ITER has matured to a stage of preliminary design with the advent of industrial associates. Starting from the cold power source, the system of Cryoline and Cryo-distribution transfers the controlled cold power through a large network to the superconducting magnets and cryopumps. The functional responsibility also includes very high reliability and availability with respect to the operation of the ITER machine. Following the completion of conceptual design, it was necessary to perform a detailed engineering study of the complete network of distribution system in totality, before entering in to the industrial phase. This is to ensure the functional responsibility of the system. Value engineering in the area of distribution boxes including interfacing Cryolines has been performed in order to access the integrated reliable performance with respect to the overall cryogenic system, reducing the risk transferred to the industrial partners. These include technical risk assessment, analysis, mitigation plan and implementation with the industrial partners. The paper describes the methodology of technical risk management, value engineering performed to ensure fulfilment of licensing and regulatory obligations, functional reliability, testing and manufacturability by standard industrial processes, so that highly reliable integrated distribution system is delivered for the project.

  16. Turbo STIR magnetic resonance imaging as a whole-body screening tool for metastases in patients with breast carcinoma: preliminary clinical experience.

    Science.gov (United States)

    Walker, R; Kessar, P; Blanchard, R; Dimasi, M; Harper, K; DeCarvalho, V; Yucel, E K; Patriquin, L; Eustace, S

    2000-04-01

    This study was undertaken to assess the utility of whole-body turbo short tau inversion recovery (STIR) magnetic resonance imaging (MRI) to detect metastases to liver, brain, and bone as a single examination in women with breast cancer. Seventeen patients with biopsy-proven breast cancer and suspected metastatic disease attending over a 12-month period referred for both conventional imaging and whole-body MRI were included in the study. Three patients were found to be free of metastases at both conventional and MR imaging. Appendicular or axial skeletal metastases were identified in 11 of 17 patients, with correlation between findings at whole-body MRI and scintigraphy in 15 of the 17 patients. Five patients had evidence of hepatic metastases on whole-body MRI, of which metastases were identified in only three patients at CT despite contrast enhancement. Four patients had brain abnormalities (metastases in three patients, meningioma in one patient) detected on both whole-body and dedicated brain MRI. Preliminary clinical experience suggests that turbo STIR whole-body MRI may represent a convenient and cost-effective method of total body screening for metastases in patients with breast carcinoma.

  17. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet and its sub-systems were stopped at the beginning of the winter shutdown on 8th December 2011. The magnet was left without cooling during the cryogenics maintenance until 17th January 2012, when the cryoplant operation resumed. The magnet temperature reached 93 K. The vacuum pumping was maintained during this period. During this shutdown, the yearly maintenance was performed on the cryogenics, the vacuum pumps, the magnet control and safety systems, and the power converter and discharge lines. Several preventive actions led to the replacement of the electrovalve command coils, and the 20A DC power supplies of the magnet control system. The filters were cleaned on the demineralised water circuits. The oil of the diffusion pumps was changed. On the cryogenics, warm nitrogen at 343 K was circulated in the cold box to regenerate the filters and the heat exchangers. The coalescing filters have been replaced at the inlet of both the turbines and the lubricant trapping unit. The active cha...

  18. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet was successfully operated at the end of the year 2009 despite some technical problems on the cryogenics. The magnet was ramped up to 3.8 T at the end of November until December 16th when the shutdown started. The magnet operation met a few unexpected stops. The field was reduced to 3.5 T for about 5 hours on December 3rd due to a faulty pressure sensor on the helium compressor. The following day the CERN CCC stopped unintentionally the power converters of the LHC and the experiments, triggering a ramp down that was stopped at 2.7 T. The magnet was back at 3.8 T about 6 hours after CCC sent the CERN-wide command. Three days later, a slow dump was triggered due to a stop of the pump feeding the power converter water-cooling circuit, during an intervention on the water-cooling plant done after several disturbances on the electrical distribution network. The magnet was back at 3.8 T in the evening the same day. On December 10th a break occurred in one turbine of the cold box producing the liquid ...

  19. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

      The magnet was operated without any problem until the end of the LHC run in February 2013, apart from a CERN-wide power glitch on 10 January 2013 that affected the CMS refrigerator, causing a ramp down to 2 T in order to reconnect the coldbox. Another CERN-wide power glitch on 15 January 2013 didn’t affect the magnet subsystems, the cryoplant or the power converter. At the end of the magnet run, the reconnection of the coldbox at 2.5 T was tested. The process will be updated, in particular the parameters of some PID valve controllers. The helium flow of the current leads was reduced but only for a few seconds. The exercise will be repeated with the revised parameters to validate the automatic reconnection process of the coldbox. During LS1, the water-cooling services will be reduced and many interventions are planned on the electrical services. Therefore, the magnet cryogenics and subsystems will be stopped for several months, and the magnet cannot be kept cold. In order to avoid unc...

  20. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

    The CMS magnet has been running steadily and smoothly since the summer, with no detected flaw. The magnet instrumentation is entirely operational and all the parameters are at their nominal values. Three power cuts on the electrical network affected the magnet run in the past five months, with no impact on the data-taking as the accelerator was also affected at the same time. On 22nd June, a thunderstorm caused a power glitch on the service electrical network. The primary water cooling at Point 5 was stopped. Despite a quick restart of the water cooling, the inlet temperature of the demineralised water on the busbar cooling circuit increased by 5 °C, up to 23.3 °C. It was kept below the threshold of 27 °C by switching off other cooling circuits to avoid the trigger of a slow dump of the magnet. The cold box of the cryogenics also stopped. Part of the spare liquid helium volume was used to maintain the cooling of the magnet at 4.5 K. The operators of the cryogenics quickly restarted ...

  1. Amide Proton Transfer Magnetic Resonance Imaging of Alzheimer′s Disease at 3.0 Tesla: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2015-01-01

    Full Text Available Background: Amide proton transfer (APT imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging (MRI in the field of molecular and cellular imaging. The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer′s disease (AD at 3.0 Tesla. Methods: Twenty AD patients (9 men and 11 women; age range, 67-83 years and 20 age-matched normal controls (11 men and 9 women; age range, 63-82 years underwent APT and traditional MRI examination on a 3.0 Tesla MRI system. The magnetic resonance ratio asymmetry (MTR asym values at 3.5 ppm of bilateral hippocampi (Hc, temporal white matter regions, occipital white matter regions, and cerebral peduncles were measured on oblique axial APT images. MTR asym (3.5 ppm values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test. Controlling for age, partial correlation analysis was used to investigate the associations between mini-mental state examination (MMSE and the various MRI measures among AD patients. Results: Compared with normal controls, MTR asym (3.5 ppm values of bilateral Hc were significantly increased in AD patients (right 1.24% ± 0.21% vs. 0.83% ± 0.19%, left 1.18% ± 0.18% vs. 0.80%± 0.17%, t = 3.039, 3.328, P = 0.004, 0.002, respectively. MTR asym (3.5 ppm values of bilateral Hc were significantly negatively correlated with MMSE (right r = −0.559, P = 0.013; left r = −0.461, P = 0.047. Conclusions: Increased MTR asym (3.5 ppm values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.

  2. Magnetic resonance imaging (MRI) of inflamed myocardium using iron oxide nanoparticles in patients with acute myocardial infarction - preliminary results.

    Science.gov (United States)

    Yilmaz, Ali; Rösch, Sabine; Klingel, Karin; Kandolf, Reinhard; Helluy, Xavier; Hiller, Karl-Heinz; Jakob, Peter M; Sechtem, Udo

    2013-02-20

    Superparamagnetic iron oxide nanoparticle (SPIO)-based molecular imaging agents targeting macrophages have been developed and successfully applied in animal models of myocardial infarction. The purpose of this clinical trial was to investigate whether magnetic resonance imaging (MRI) of macrophages using ferucarbotran (Resovist®) allows improved visualisation of the myocardial (peri-)infarct zone compared to conventional gadolinium-based necrosis/fibrosis imaging in patients with acute myocardial infarction. The clinical study NIMINI-1 was performed as a prospective, non-randomised, non-blinded, single agent phase III clinical trial (NCT0088644). Twenty patients who had experienced either an acute ST-elevation or non-ST-elevation myocardial infarction (STEMI/NSTEMI) were included to this study. Following coronary angiography, a first baseline cardiovascular magnetic resonance (CMR) study (pre-SPIO) was performed within seven days after onset of cardiac symptoms. A second CMR study (post-SPIO) was performed either 10 min, 4h, 24h or 48h after ferucarbotran administration. The CMR studies comprised cine-CMR, T2-weighted "edema" imaging, T2-weighted cardiac imaging and T1-weighted late-gadolinium-enhancement (LGE) imaging. The median extent of short-axis in-plane LGE was 28% (IQR 19-31%). Following Resovist® administration the median extent of short-axis in-plane T2-weighted hypoenhancement (suggestive of intramyocardial haemorrhage and/or SPIO accumulation) was 0% (IQR 0-9%; p=0.68 compared to pre-SPIO). A significant in-slice increase (>3%) in the extent of T2-weighted "hypoenhancement" (post-SPIO compared to pre-SPIO) was seen in 6/16 patients (38%). However, no patient demonstrated "hypoenhancement" in T2-weighted images following Resovist® administration that exceeded the area of LGE. T2/T2-weighted MRI aiming at non-invasive myocardial macrophage imaging using the approved dose of ferucarbotran does not allow improved visualisation of the myocardial (peri

  3. Bounded Fixed-Point Iteration

    DEFF Research Database (Denmark)

    Nielson, Hanne Riis; Nielson, Flemming

    1992-01-01

    they obtain a quadratic bound. These bounds are shown to be tight. Specializing the case of strict and additive functions to functionals of a form that would correspond to iterative programs they show that a linear bound is tight. This is related to several analyses studied in the literature (including...

  4. Iterative method for interferogram processing

    Science.gov (United States)

    Kotlyar, Victor V.; Seraphimovich, P. G.; Zalyalov, Oleg K.

    1994-12-01

    We have developed and numerically evaluated an iterative algorithm for interferogram processing including the Fourier-transform method, the Gerchberg-Papoulis algorithm and Wiener's filter-based regularization used in combination. Using a signal-to-noise ratio not less than 1, it has been possible to reconstruct the phase of an object field with accuracy better than 5%.

  5. Energetic ions in ITER plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Pinches, S. D. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul-lez-Durance Cedex (France); Chapman, I. T.; Sharapov, S. E. [CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Lauber, Ph. W. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, Boltzmanstraße 2, D-85748 Garching (Germany); Oliver, H. J. C. [H H Wills Physics Laboratory, University of Bristol, Royal Fort, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Shinohara, K. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Tani, K. [Nippon Advanced Technology Co., Ltd, Naka, Ibaraki 311-0102 (Japan)

    2015-02-15

    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.

  6. Energetic ions in ITER plasmas

    Science.gov (United States)

    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.

  7. Iterative Specialisation of Horn Clauses

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Rosenkilde; Nielson, Flemming; Nielson, Hanne Riis

    2008-01-01

    We present a generic algorithm for solving Horn clauses through iterative specialisation. The algorithm is generic in the sense that it can be instantiated with any decidable fragment of Horn clauses, resulting in a solution scheme for general Horn clauses that guarantees soundness and terminatio...

  8. Cooperation between CERN and ITER

    CERN Multimedia

    CERN Audiovisual Service

    2008-01-01

    CERN and the International Fusion Organisation ITER have just signed a first cooperation agreeement. The Director-General of the International Fusion Energy Organization, Mr Kaname Ikeda, and CERN Director-General, Robert Aymar, signed a cooperation agreement at a meeting on the Meyrin site on Thursday 6 March.

  9. Metabolomic analysis of urine with Nuclear Magnetic Resonance spectroscopy in patients with idiopathic sudden sensorineural hearing loss: A preliminary study.

    Science.gov (United States)

    Carta, Filippo; Lussu, Milena; Bandino, Fabrizio; Noto, Antonio; Peppi, Marcello; Chuchueva, Natalia; Atzori, Luigi; Fanos, Vassilios; Puxeddu, Roberto

    2017-08-01

    Idiopathic sudden sensorineural hearing loss is a frequent emergency, with unknown aetiology and usually treated with empiric therapy. Steroids represent the only validated treatment but prognosis is unpredictable and the possibility to select the patients who will not respond to steroids could avoid unnecessary treatments. Metabolomic profiling of the biofluids target the analysis of the final product of genic expression and enzymatic activity, defining the biochemical phenotype of a whole biologic system. We studied the metabolomics of the urine of a cohort of patients with idiopathic sudden sensorineural hearing loss, correlating the metabolic profiles with the clinical outcomes. Metabolomic profiling of urine samples was performed by (1)H Nuclear Magnetic Resonance spectroscopy in combination with multivariate statistical approaches. 26 patients were included in the study: 5 healthy controls, 13 patients who did not recover after treatment at 6 months while the remaining 8 patients recovered from the hearing loss. The orthogonal partial least square-discriminant analysis score plot showed a significant separation between the two groups, responders and non-responders after steroid therapy, R(2)Y of 0.83, Q(2) of 0.38 and p value sudden sensorineural hearing loss is a specific disease with unclear systemic changes, but our data suggest that there are different types of this disorder or patients predisposed to effective action of steroids allowing the recover after treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Radiofrequency ablation of small liver malignancies under magnetic resonance guidance: progress in targeting and preliminary observations with temperature monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Terraz, Sylvain; Cernicanu, Alexandru; Lepetit-Coiffe, Matthieu; Viallon, Magalie; Salomir, Rares; Becker, Christoph D. [University Hospitals of Geneva, Department of Radiology, Geneva 14 (Switzerland); Mentha, Gilles [University Hospitals of Geneva, Department of Visceral Surgery and Transplantation, Geneva (Switzerland)

    2010-04-15

    To evaluate the feasibility and effectiveness of magnetic resonance (MR)-guided radiofrequency (RF) ablation for small liver tumours with poor conspicuity on both contrast-enhanced ultrasonography (US) and computed tomography (CT), using fast navigation and temperature monitoring. Sixteen malignant liver nodules (long-axis diameter, 0.6-2.4 cm) were treated with multipolar RF ablation on a 1.5-T wide-bore MR system in ten patients. Targeting was performed interactively, using a fast steady-state free precession sequence. Real-time MR-based temperature mapping was performed, using gradient echo-echo planar imaging (GRE-EPI) and hardware filtering. MR-specific treatment data were recorded. The mean follow-up time was 19 {+-} 7 months. Correct placement of RF electrodes was obtained in all procedures (image update, <500 ms; mean targeting time, 21 {+-} 11 min). MR thermometry was available for 14 of 16 nodules (88%) with an accuracy of 1.6 C in a non-heated region. No correlation was found between the size of the lethal thermal dose and the ablation zone at follow-up imaging. The primary and secondary effectiveness rates were 100% and 91%, respectively. RF ablation of small liver tumours can be planned, targeted, monitored and controlled with MR imaging within acceptable procedure times. Temperature mapping is technically feasible, but the clinical benefit remains to be proven. (orig.)

  11. Cancer and diverticulitis of the sigmoid colon. Differentiation with computed tomography versus magnetic resonance imaging - Preliminary experiences

    Energy Technology Data Exchange (ETDEWEB)

    Oeistaemoe, Emma; Hjern, Fredrik; Abraham-Nordling, Mirna [Dept. of Clinical Sciences, Div. of Surgery, Danderyd Hospital, Karolinska Institutet, Stockholm (Sweden)], e-mail: mirna.abraham.nordling@ki.se; Blomqvist, Lennart [Dept. of Diagnostic Radiology, Dept. of Molecular Medicine and Surgery Karolinska Univ. Hospital Solna and Karolinska Institutet, Stockholm (Sweden); Von Heijne, Anders [Dept. of Clinical Sciences, Div. of Radiology, Danderyd Hospital, Karolinska Institutet, Stockholm (Sweden)

    2013-04-15

    Background: Both colon cancer and diverticular disease are common in the Western world. A challenge when patients present with clinical findings is that both diseases can present with symptoms that may mimic the other. Purpose: To determine whether magnetic resonance imaging (MRI) could be helpful to differentiate between diverticulitis and cancer of the sigmoid colon compared to the differentiation offered by evaluation of multidetector computed tomography (CT) in a clinical situation. Material and Methods: Thirty patients were consecutively included. Fifteen patients were under work-up for a recently diagnosed sigmoid cancer and 15 patients had recently been treated in hospital due to first-time acute sigmoid diverticulitis. All patients underwent CT, T2- weighted MRI and diffusion-weighted MRI. Anonymized examinations were retrospectively presented in random order to one experienced radiologist. Results: With contrast-enhanced CT, the sensitivity and specificity for diagnosis of cancer and diverticulitis were 66.7% (10/15) and 93.3% (14/15), respectively. Using T2-weighted and diffusion-weighted MR images, the sensitivity and specificity for diagnosis of cancer and diverticulitis were 100% (14/14) and 100% (14/14), respectively. Conclusion: MRI provides information that may contribute to improve the differentiation between sigmoid cancer and diverticulitis that is offered by CT. These encouraging results need to be confirmed in a larger study.

  12. Peripheral nerve tractography in soft tissue tumors: a preliminary 3-tesla diffusion tensor magnetic resonance imaging study.

    Science.gov (United States)

    Kasprian, Gregor; Amann, Gabriele; Panotopoulos, Joannis; Schmidt, Manfred; Dominkus, Martin; Trattnig, Siegfried; Windhager, Reinhard; Prayer, Daniela; Nöbauer-Huhmann, Iris

    2015-03-01

    This diffusion tensor magnetic resonance imaging (DTI) study aimed to clarify the relationship of peripheral nerves and soft tissue tumors (STTs) in 3D to optimize subsequent treatment. Twenty-six consecutive STT patients (histologically malignant, n=10; intermediate, n=3; and benign, n=13) underwent 3-Tesla MRI using an echoplanar DTI sequence. Deterministic tractography was performed. Fractional anisotropy (FA) values were measured within peritumoral and distant regions of interest. Tractography depicted the 3D course of the sciatic (n=12), femoral (n=2), tibial (n=7), fibular (n=2), median (n=1), musculocutaneous (n=1), and ulnar (n=1) nerves in a regular (n=8 of 18, 44.4%) or thinned (n=7 of 18, 38.9%) fashion. The lowest peritumoral FA values, abrupt thinning, and/or complete discontinuity of trajectories were found in 2 cases with histologically proven tumoral nerve infiltration. DTI clarifies the 3D topography between major peripheral nerves and STTs and may be helpful in the assessment of peripheral nerve infiltration by malignant tumors. © 2014 Wiley Periodicals, Inc.

  13. Bihemispheric repetitive transcranial magnetic stimulation combined with intensive occupational therapy for upper limb hemiparesis after stroke: a preliminary study.

    Science.gov (United States)

    Yamada, Naoki; Kakuda, Wataru; Kondo, Takahiro; Shimizu, Masato; Mitani, Sugao; Abo, Masahiro

    2013-12-01

    We investigated the safety, feasibility, and efficacy of the combination of bihemispheric repetitive transcranial magnetic stimulation (rTMS) and intensive occupational therapy (OT) for upper limb hemiparesis in poststroke patients. The study participants were eight poststroke patients with upper limb hemiparesis (age at intervention: 62.8±4.9 years, time after stroke: 84.3±87.2 months, mean±SD). During 15 days of hospitalization, each patient received 10 sessions of 40-min bihemispheric rTMS and 240-min intensive OT (120-min one-to-one training and 120-min self-training). One session of bihemispheric rTMS comprised the application of both 1 and 10 Hz rTMS (2000 stimuli for each hemisphere). The Fugl-Meyer Assessment, Wolf Motor Function Test, and the Modified Ashworth Scale were administered on the day of admission and at discharge. All patients completed the treatment without any adverse effects. Motor function of the affected upper limb improved significantly, on the basis of changes in Fugl-Meyer Assessment and Wolf Motor Function Test (Ptherapy for poststroke hemiparetic patients, and improved motor function of the hemiparetic upper limb in poststroke patients. The findings provide a new avenue for the treatment of patients with poststroke hemiparesis.

  14. Perfusion of subchondral bone marrow in knee osteoarthritis: A dynamic contrast-enhanced magnetic resonance imaging preliminary study.

    Science.gov (United States)

    Budzik, Jean-François; Ding, Juliette; Norberciak, Laurène; Pascart, Tristan; Toumi, Hechmi; Verclytte, Sébastien; Coursier, Raphaël

    2017-03-01

    The role of inflammation in the pathogenesis of osteoarthritis is being given major interest, and inflammation is closely linked with vascularization. It was recently demonstrated that dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could identify the subchondral bone marrow vascularization changes occurring in osteoarthritis in animals. These changes appeared before cartilage lesions were visible and were correlated with osteoarthritis severity. Thus the opportunity to obtain an objective assessment of bone vascularization in non-invasive conditions in humans might help better understanding osteoarthritis pathophysiology and finding new biomarkers. We hypothesized that, as in animals, DCE-MRI has the ability to identify subchondral bone marrow vascularization changes in human osteoarthritis. We performed knee MRI in 19 patients with advanced knee osteoarthritis. We assessed subchondral bone marrow vascularization in medial and lateral femorotibial compartments with DCE-MRI and graded osteoarthritis lesions on MR images. Statistical analysis assessed intra- and inter-observer agreement, compared DCE-MRI values between the different subchondral zones, and sought for an influence of age, sex, body mass index, and osteoarthritis garde on these values. The intra- and inter-observer agreement for DCE-MRI values were excellent. These values were significantly higher in the femorotibial compartment the most affected by osteoarthritis, both in femur and tibia (posteoarthritis severity in humans.

  15. Intra-epiphyseal stress injury of the proximal tibial epiphysis: Preliminary experience of magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Tony, G., E-mail: drgtony@gmail.com [Stafford General Hospital, Weston Road, Stafford, Staffordshire ST16 3SA (United Kingdom); Charran, A., E-mail: amandacharran@yahoo.com [Hillingdon Hospital, Pield Heath Rd, Uxbridge, Middlesex UB8 3NN (United Kingdom); Tins, B., E-mail: bernhard.tins@rjah.nhs.uk [Department of Diagnostic Imaging, Robert Jones and Agnes Hunt, Orthopaedic Hospital, Oswestry, Shropshire SY10 7 AG (United Kingdom); Lalam, R., E-mail: radhesh.lalam@rjah.nhs.uk [Department of Diagnostic Imaging, Robert Jones and Agnes Hunt, Orthopaedic Hospital, Oswestry, Shropshire SY10 7 AG (United Kingdom); Tyrrell, P.N.M., E-mail: prudencia.tyrrell@rjah.nhs.uk [Department of Diagnostic Imaging, Robert Jones and Agnes Hunt, Orthopaedic Hospital, Oswestry, Shropshire SY10 7 AG (United Kingdom); Singh, J., E-mail: jaspreet.singh@rjah.nhs.uk [Department of Diagnostic Imaging, Robert Jones and Agnes Hunt, Orthopaedic Hospital, Oswestry, Shropshire SY10 7 AG (United Kingdom); Cool, P., E-mail: paul.cool@rjah.nhs.uk [Orthopaedic Oncology, Robert Jones and Agnes Hunt, Orthopaedic Hospital, Oswestry, Shropshire SY10 7 AG (United Kingdom); Kiely, N., E-mail: nigel.kiely@rjah.nhs.uk [Paediatric Orthopaedics, Robert Jones and Agnes Hunt, Orthopaedic Hospital, Oswestry, Shropshire SY10 7 AG (United Kingdom); Cassar-Pullicino, V.N., E-mail: Victor.Pullicino@rjah.nhs.uk [Department of Diagnostic Imaging, Robert Jones and Agnes Hunt, Orthopaedic Hospital, Oswestry, Shropshire SY10 7 AG (United Kingdom)

    2014-11-15

    Highlights: • Purely intra-epiphyseal stress injuries of the proximal tibial epiphysis are described for the first time. • The variation in the MRI findings of these injuries depending on the stage of maturation is demonstrated. • We postulate a patho-mechanism to explain the variations in site and appearance of stress injuries in this region. - Abstract: Stress induced injuries affecting the physeal plate or cortical bone in children and adolescents, especially young athletes, have been well described. However, there are no reports in the current English language literature of stress injury affecting the incompletely ossified epiphyseal cartilage. We present four cases of stress related change to the proximal tibial epiphysis (PTE) along with their respective magnetic resonance imaging (MRI) appearances ranging from subtle oedema signal to a pseudo-tumour like appearance within the epiphyseal cartilage. The site and pattern of intra-epiphyseal injury is determined by the type of tissue that is affected, the maturity of the skeleton and the type of forces that are transmitted through the tissue. We demonstrate how an awareness of the morphological spectrum of MRI appearances in intra-epiphyseal stress injury and the ability to identify concomitant signs of stress in other nearby structures can help reduce misdiagnosis, avoid invasive diagnostic procedures like bone biopsy and reassure patients and their families.

  16. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hellermann, M.G. von, E-mail: mgvh@jet.u [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Barnsley, R. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Biel, W. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Delabie, E. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Hawkes, N. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Jaspers, R. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Johnson, D. [Princeton Plasma Physics Laboratory, Princeton, NJ-08548 (United States); Klinkhamer, F. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Lischtschenko, O. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Marchuk, O. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Schunke, B. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Singh, M.J. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India); Snijders, B. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Summers, H.P. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Thomas, D. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Tugarinov, S. [TRINITI Troitsk, Moscow Region 142092 (Russian Federation); Vasu, P. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India)

    2010-11-11

    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 (0ITER 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. MAGNETS

    Science.gov (United States)

    Hofacker, H.B.

    1958-09-23

    This patent relates to nmgnets used in a calutron and more particularly to means fur clamping an assembly of magnet coils and coil spacers into tightly assembled relation in a fluid-tight vessel. The magnet comprises windings made up of an assembly of alternate pan-cake type coils and spacers disposed in a fluid-tight vessel. At one end of the tank a plurality of clamping strips are held firmly against the assembly by adjustable bolts extending through the adjacent wall. The foregoing arrangement permits taking up any looseness which may develop in the assembly of coils and spacers.

  18. Recent results on ITER plasma equilibrium diagnostics and identification

    Energy Technology Data Exchange (ETDEWEB)

    Albanese, R.; Coccorese, E.; Morabito, F.C.; Pironti, A.; Versaci, M. [Associazione CREATE/ENEA/EURATOM - DIMET, Loc. Feo di Vito, Reggio Calabria (Italy); Mc Carthy, P.J. [Cork Univ. College (Ireland). Physics Dept.

    1998-07-01

    The most recent results achieved by our work-group on the plasma shape and position identification problem as well as on the interpretation of magnetic diagnostics are presented. The proposed test cases are related to the most recent configuration of sensors and geometry specification available from ITER. One of the aims of the work is also to give some design directions about the problem of optimal selection of the diagnostics for control parameters. (author)

  19. The efficiency of Gd-EOB-DTPA-enhanced magnetic resonance cholangiography in living donor liver transplantation: a preliminary study.

    Science.gov (United States)

    Ogul, Hayri; Kantarci, Mecit; Pirimoglu, Berhan; Karaca, Leyla; Aydinli, Bulent; Okur, Aylin; Ozturk, Gurkan; Kizrak, Yesim

    2014-03-01

    The aim of this study was to evaluate utility of gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (MRC) for the detection of biliary complications after living donor liver transplantation (LDLT). A total of 18 patients with suspected biliary complications underwent MRC. T2-weighted MRC and contrast-enhanced MRC (CE-MRC) were used to identify the biliary complications. MRC included routine breath-hold T2-weighted MRC using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences and Gd-EOB-DTPA-enhanced MRC T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences. Before confirming the biliary complications, one observer reviewed the MRC images and the CE-MRC images separately. The verification procedures and MRC findings were compared, and the sensitivity, specificity, and accuracy of both techniques were calculated for the identification of biliary complications. The observer found six of seven biliary complications using CE-MRC. The sensitivity was 85.7% and the accuracy was 94.4%. Using MRC alone, sensitivity was 57.1% and accuracy was 55.5%. The accuracy of Gd-EOB-DTPA-enhanced MRC was superior to MRC in locating biliary leaks (p < 0.05). The usage of Gd-EOB-DTPA-enhanced MRC yields information that complements the MRC findings that improve the identification of biliary complications. We recommend the use of MRC in addition to Gd-EOB-DTPA-enhanced MRC to increase the preoperative accuracy when assessing the biliary complications after LDLT.

  20. [Postoperative monitoring of free fibular grafts by dynamic magnetic resonance imaging. Preliminary results in three cases of mandibular reconstruction].

    Science.gov (United States)

    Bey, E; Paranque, A; Pharaboz, C; Cariou, J L

    2001-02-01

    The vascularized free fibular graft has been used in mandibular reconstructive surgery since 1975. This technique has been progressively developed, and it is now the procedure of choice for mandibular reconstruction although in certain postoperative circumstances it can be difficult if not impossible to monitor bone vitality. However, bone vascularization can be detected by dynamic magnetic resonance imaging (MRI), as this technique has been experimentally and clinically validated in the early diagnosis of osteonecrosis. The aim of this study was to evaluate the efficacy of MRI for the postoperative monitoring of vascularized free fibular grafts in human mandibular reconstruction. Dynamic contrast-enhanced MRI was used to study the variation in contrast over time following injection of gadolinium contrast medium, and to evaluate the degree of bone marrow perfusion of the fibular graft. This variation in signal intensity was visualized in the form of a curve, i.e., a perfusion curve for the bone marrow region. An examination was performed in three patients at different postoperative times and under different conditions. In one case, MRI confirmed the presence of fibula blood supply in spite of the necrosis of the adjacent fascio-adipose layer. In this article, the methodological difficulties have been discussed, particularly as regards data processing, and the present results have been compared with the findings in the literature. Dynamic MRI is a simple, reliable, non-invasive technique and its use in the postoperative monitoring of bone marrow perfusion and vascularized free fibular grafts permits a determination of the status of the latter following surgery, i.e., whether there is an adequate blood supply or not.

  1. Validation of model-based brain shift correction in neurosurgery via intraoperative magnetic resonance imaging: preliminary results

    Science.gov (United States)

    Luo, Ma; Frisken, Sarah F.; Weis, Jared A.; Clements, Logan W.; Unadkat, Prashin; Thompson, Reid C.; Golby, Alexandra J.; Miga, Michael I.

    2017-03-01

    The quality of brain tumor resection surgery is dependent on the spatial agreement between preoperative image and intraoperative anatomy. However, brain shift compromises the aforementioned alignment. Currently, the clinical standard to monitor brain shift is intraoperative magnetic resonance (iMR). While iMR provides better understanding of brain shift, its cost and encumbrance is a consideration for medical centers. Hence, we are developing a model-based method that can be a complementary technology to address brain shift in standard resections, with resource-intensive cases as referrals for iMR facilities. Our strategy constructs a deformation `atlas' containing potential deformation solutions derived from a biomechanical model that account for variables such as cerebrospinal fluid drainage and mannitol effects. Volumetric deformation is estimated with an inverse approach that determines the optimal combinatory `atlas' solution fit to best match measured surface deformation. Accordingly, preoperative image is updated based on the computed deformation field. This study is the latest development to validate our methodology with iMR. Briefly, preoperative and intraoperative MR images of 2 patients were acquired. Homologous surface points were selected on preoperative and intraoperative scans as measurement of surface deformation and used to drive the inverse problem. To assess the model accuracy, subsurface shift of targets between preoperative and intraoperative states was measured and compared to model prediction. Considering subsurface shift above 3 mm, the proposed strategy provides an average shift correction of 59% across 2 cases. While further improvements in both the model and ability to validate with iMR are desired, the results reported are encouraging.

  2. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

    The magnet ran smoothly in the last few months until a fast dump occurred on 9th May 2011. Fortunately, this occurred in the afternoon of the first day of the technical stop. The fast dump was due to a valve position controller that caused the sudden closure of a valve. This valve is used to regulate the helium flow on one of the two current leads, which electrically connects the coil at 4.5 K to the busbars at room temperature. With no helium flow on the lead, the voltage drop and the temperatures across the leads increase up to the defined thresholds, triggering a fast dump through the Magnet Safety System (MSS). The automatic reaction triggered by the MSS worked properly. The helium release was limited as the pressure rise was just at the limit of the safety valve opening pressure. The average temperature of the magnet reached 72 K. It took four days to recover the temperature and refill the helium volumes. The faulty valve controller was replaced by a spare one before the magnet ramp-up resumed....

  3. Safety Analysis Results for Cryostat Ingress Accidents in ITER

    Science.gov (United States)

    Merrill, B. J.; Cadwallader, L. C.; Petti, D. A.

    1997-06-01

    Accidents involving the ingress of air, helium, or water into the cryostat of the International Thermonuclear Experimental Reactor (ITER) tokamak design have been analyzed with a modified version of the MELCOR code for the ITER Non-site Specific Safety Report (NSSR-1). The air ingress accident is the result of a postulated breach of the cryostat boundary into an adjoining room. MELCOR results for this accident demonstrate that the condensed air mass and increased heat loads are not a magnet safety concern, but that the partial vacuum in the adjoining room must be accommodated in the building design. The water ingress accident is the result of a postulated magnet arc that results in melting of a Primary Heat Transport System (PHTS) coolant pipe, discharging PHTS water and PHTS water activated corrosion products and HTO into the cryostat. MELCOR results for this accident demonstrate that the condensed water mass and increased heat loads are not a magnet safety concern, that the cryostat pressure remains below design limits, and that the corrosion product and HTO releases are well within the ITER release limits.

  4. Fat-Suppressed T2 Sequences for Routine 3.0-Tesla Lumbar Spine Magnetic Resonance Imaging: A Preliminary Report

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, A. M.; Gadani, S.; Palmer, C. S.; Vidarsson, L. (Dept. of Radiology, Hennepin County and Univ. of Minnesota Medical Centers, Minneapolis, MN (United States))

    2008-09-15

    Background: Clear depiction of the ligamentum flavum on routine lumbar magnetic resonance imaging (MRI) is essential in accurately describing the extent of degenerative disease. In routine, noncontrast evaluations, focal fatty deposition or hemangiomas can be difficult to distinguish from malignant foci on fast spin-echo (FSE) T2-weighted images. Purpose: To describe the use of T2 fast field echo (T2FFE) in combination with spectral presaturation inversion recovery (SPIR) fat suppression for noncontrast, routine lumbar spine outpatient MR imaging at 3.0 Tesla (3T). Material and Methods: An axial gradient echo (GE) T2FFE sequence was combined with SPIR fat suppression (T2FFE-SPIR), via a 3T Philips Intera (Philips Medical Systems, Best, The Netherlands) scanner, and added to the routine, noncontrast lumbar MRI examinations, which included sagittal FSE T1-weighted (T1WI), T2-weighted (T2WI), short-tau inversion recovery (STIR), and axial FSE T2WI. The sequence was performed in over 500 patients over a 1-year period, without intravenous contrast, and with slice thickness and planes of section identical to the axial FSE T1WI and T2WI images. The sequence typically lasted about 4.5-6 min. Results: The use of T2FFE-SPIR enabled visualization of the ligamentum flavum in degenerative disease, and the exclusion of focal fatty lesions on FSE T2WI. Other benefits included: the identification of malignant foci, the uncommon detection of hemorrhage, and the elimination of spurious flow voids. Several brief examples are provided to demonstrate the utility of this technique. Conclusion: The addition of T2FFE-SPIR to routine, noncontrast protocols in outpatients could provide further confidence in the visualization of the ligamentum flavum in degenerative disease, and can exclude malignancy in T2-bright areas of focal fatty marrow. Larger studies would be helpful to evaluate the accuracy of this technique versus FSE techniques in depicting degenerative, malignant, or inflammatory

  5. Preliminary assessment of cardiac short term safety and efficacy of manganese chloride for cardiovascular magnetic resonance in humans

    Directory of Open Access Journals (Sweden)

    Kalaf Jose M

    2011-01-01

    Full Text Available Abstract Background Manganese based agents are intracellular and accumulate inside myocytes allowing for different imaging strategies compared to gadolinium contrasts. While previous agents release manganese very slowly in the circulation, MnCl2 allows for rapid Mn2+ uptake in myocytes, creating a memory effect that can be potentially explored. Data on animal models are very encouraging but the safety and efficacy of this approach in humans has not yet been investigated. Therefore, our objectives were to study the safety and efficacy of a rapid infusion of manganese chloride (MnCl2 for cardiovascular magnetic resonance (CMR in humans. Methods Fifteen healthy volunteers underwent a CMR scan on a 1.5 T scanner. Before the infusion, cardiac function was calculated and images of a short axis mid-ventricular slice were obtained using a 2D and 3D gradient-echo inversion recovery (GRE-IR sequence, a phase-sensitive IR sequence and a single breath-hold segmented IR prepared steady-state precession acquisition for T1 calculations. MnCl2 was infused over three minutes at a total dose of 5 μMol/kg. Immediately after the infusion, and at 15 and 30 minutes later, new images were obtained and cardiac function re-evaluated. Results There was a significant decrease in T1 values compared to baseline, sustained up to 30 minutes after the MnCl2 infusion (pre,839 ± 281 ms; 0 min, 684 ± 99; 15 min, 714 ± 168; 30 min, 706 ± 172, P = 0.003. The 2D and 3D GRE-IR sequence showed the greatest increase in signal-to-noise ratio compared to the other sequences (baseline 6.6 ± 4.2 and 9.7 ± 5.3; 0 min, 11.3 ± 4.1 and 15.0 ± 8.7; 15 min, 10.8 ± 4.0 and 16.9 ± 10.2; 30 min, 10.6 ± 5.2 and 16.5 ± 8.3, P 2 with no major adverse events, despite all reporting transient facial flush. Conclusions In the short term, MnCl2 appears safe for human use. It effectively decreases myocardium T1, maintaining this effect for a relatively long period of time and allowing for the

  6. ITERATIVE ALGORITHMS FOR DATA ASSIMILATION PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Iterative algorithms for solving the data assimilation problems are considered, based on the main and adjoint equations. Spectral properties of the control operators of the problem are studied, the iterative algorithms are justified.

  7. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

    Madsen, Kaj; Caprani, O.; Stauning, Ole

    1997-01-01

    In the search for regions that contain fixed points ofa real function of several variables, tests based on interval calculationscan be used to establish existence ornon-existence of fixed points in regions that are examined in the course ofthe search. The search can e.g. be performed...... as a synchronous (sequential) interval iteration:In each iteration step all components of the iterate are calculatedbased on the previous iterate. In this case it is straight forward to base simple interval existence and non-existencetests on the calculations done in each step of the iteration. The search can also...... be performed as an asynchronous (parallel) iteration: Only a few components are changed in each stepand this calculation is in general based on components from differentprevious iterates. For the asynchronous iteration it turns out thatsimple tests of existence and non-existence can be based...

  8. Fast iteration of cocyles over rotations and Computation of hyperbolic bundles

    CERN Document Server

    Huguet, Gemma; Sire, Yannick

    2011-01-01

    In this paper, we develop numerical algorithms that use small requirements of storage and operations for the computation of hyperbolic cocycles over a rotation. We present fast algorithms for the iteration of the quasi-periodic cocycles and the computation of the invariant bundles, which is a preliminary step for the computation of invariant whiskered tori.

  9. Overview of recent developments in pellet injection for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Combs, Stephen Kirk, E-mail: combssk@ornl.gov [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6169 (United States); Baylor, L.R.; Meitner, S.J.; Caughman, J.B.O.; Rasmussen, D.A. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6169 (United States); Maruyama, S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Status of the ITER pellet injection system. Black-Right-Pointing-Pointer Fueling requirements for ITER. Black-Right-Pointing-Pointer Summarizes the design/operating parameters and highlights recent developments. Black-Right-Pointing-Pointer Benefits of plasma fueling by the injection of pellets, composed of frozen hydrogen isotopes and millimeters in size, into magnetically confined plasmas (core fueling). Black-Right-Pointing-Pointer ELM mitigation with pellets (ELM pacing). - Abstract: Pellet injection is the primary fueling technique planned for core fueling of ITER burning plasmas. Also, the injection of relatively small pellets to purposely trigger rapid small edge localized modes (ELMs) has been proposed as a possible solution to the heat flux damage from larger natural ELMs likely to be an issue on the ITER divertor surfaces. The ITER pellet injection system is designed to inject pellets into the plasma through both inner and outer wall guide tubes. The inner wall guide tubes will provide high throughput pellet fueling while the outer wall guide tubes will be used primarily to trigger ELMs at a high frequency (>15 Hz). The pellet fueling rate of each injector is to be up to 120 Pa m{sup 3}/s, which will require the formation of solid D-T at a volumetric rate of {approx}1500 mm{sup 3}/s. Two injectors are to be provided for ITER at the startup with a provision for up to six injectors during the D-T phase. The required throughput of each injector is greater than that of any injector built to date, and a novel twin-screw continuous extrusion system is being developed to meet the challenging design parameters. Status of the development activities is presented, highlighting recent progress.

  10. REMARK ON STABILITY OF ISHIKAWA ITERATIVE PROCEDURES

    Institute of Scientific and Technical Information of China (English)

    薛志群; 田虹

    2002-01-01

    The stability of the Ishikawa iteration procedures was studied for one class ofcontinuity strong pseudocontraction and continuity strongly accretive operators with boundedrange in real uniformly smooth Banach space. Under parameters satisfying certainconditions, the convergence of iterative sequences was proved. The results improve andextend the recent corresponding results, and supply the basis of theory for further discussingconvergence of iteration procedures with errors.

  11. On One-Point Iterations and DIIS

    DEFF Research Database (Denmark)

    Østerby, Ole; Sørensen, Hans Henrik Brandenborg

    2009-01-01

    We analyze various iteration procedures in many dimensions inspired by the SCF iteration used in first principles electronic structure calculations. We show that the simple mixing of densities can turn a divergent (or slowly convergent) iteration into a (faster) convergent process provided all th...

  12. An Iterative Rejection Sampling Method

    CERN Document Server

    Sherstnev, A

    2008-01-01

    In the note we consider an iterative generalisation of the rejection sampling method. In high energy physics, this sampling is frequently used for event generation, i.e. preparation of phase space points distributed according to a matrix element squared $|M|^2$ for a scattering process. In many realistic cases $|M|^2$ is a complicated multi-dimensional function, so, the standard von Neumann procedure has quite low efficiency, even if an error reducing technique, like VEGAS, is applied. As a result of that, many of the $|M|^2$ calculations go to ``waste''. The considered iterative modification of the procedure can extract more ``unweighted'' events, i.e. distributed according to $|M|^2$. In several simple examples we show practical benefits of the technique and obtain more events than the standard von Neumann method, without any extra calculations of $|M|^2$.

  13. ITER LHCD plans and design

    Energy Technology Data Exchange (ETDEWEB)

    Bibet, Ph.; Beaumont, B.; Delpech, L.; Ekedahl, A.; Kazarian, F.; Litaudon, X.; Prou, M. [CEA Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France); Belo, J.H.; Bizarro, J.P.S. [Centro de Fusao Nuclear, Associacao Euratom-IST, Instituto Superior Tecnico, Lisboa (Portugal); Granucci, G. [Associazione EURATOM-ENEA sulla Fusione, Milano (Italy); Kuzikov, S. [Institute of Applied Physics, Nizhny Novgorod (Russian Federation); Mailloux, J. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Mirizzi, F.; Pericoli, V.; Tuccillo, A.A. [Association Euratom-ENEA sulla Fusione, Centro Ricerche Energia Frascati (Italy); Rantamaki, K. [Association Euratom-Tekes, VTT (Finland)

    2005-07-01

    LH waves experimentally exhibit the highest Current Drive efficiency at low plasma temperature, therefore they are the most suitable candidates for controlling the current profile in the off axis part of ITER Steady State plasmas. For this purpose, a 5 GHz, 20 MW CW LH system has been designed, that relies on a generator made of 24 klystrons, 1 MW each, 60 metres long circular oversized transmission lines, one antenna, based on the Passive Active Multi-function (PAM) concept. High reliability of the launcher is achieved, by limiting the power density to 33 MW/m{sup 2}. Together with the overall system description, the present results achieved toward ITER are presented. The different ongoing project are listed. The remaining outstanding problems are depicted. (authors)

  14. Experimental developments towards an ITER thermography diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Reichle, R. [Association EURATOM-CEA, DSM/DRFC, CEA Cadarache, F-13108 St. Paul-lez-Durance (France)]. E-mail: roger.reichle@cea.fr; Brichard, B. [SCK.CEN, EURATOM Ass. Belgium, Boeretang 200, B-2400 Mol (Belgium); Escourbiac, F. [Association EURATOM-CEA, DSM/DRFC, CEA Cadarache, F-13108 St. Paul-lez-Durance (France); Gardarein, J.L. [Association EURATOM-CEA, DSM/DRFC, CEA Cadarache, F-13108 St. Paul-lez-Durance (France); Hernandez, D. [PROMES CNRS 8521, Centre Felix Trombe, BP5, Odeillo, F-66125 Font Romeu (France); Le Niliot, C. [IUSTI UMR CNRS 65 95, Uni. de Provence, 5 rue Enrico Fermi, F-13453 Marseille (France); Rigollet, F. [IUSTI UMR CNRS 65 95, Uni. de Provence, 5 rue Enrico Fermi, F-13453 Marseille (France); Serra, J.J. [DGA/DET/CEP/LOT/EHF, 10 rue des fours solaires, BP 6, F-66125 Font Romeu (France); Badie, J.M. [PROMES CNRS 8521, Centre Felix Trombe, BP5, Odeillo, F-66125 Font Romeu (France); van Ierschot, S. [SCK.CEN, EURATOM Ass. Belgium, Boeretang 200, B-2400 Mol (Belgium); Jouve, M. [Association EURATOM-CEA, DSM/DRFC, CEA Cadarache, F-13108 St. Paul-lez-Durance (France); Martinez, S. [IUSTI UMR CNRS 65 95, Uni. de Provence, 5 rue Enrico Fermi, F-13453 Marseille (France); Ooms, H. [SCK.CEN, EURATOM Ass. Belgium, Boeretang 200, B-2400 Mol (Belgium); Pocheau, C. [Association EURATOM-CEA, DSM/DRFC, CEA Cadarache, F-13108 St. Paul-lez-Durance (France); Rauber, X. [ENSAM, 2, cours des Arts et Metiers, F-13617 Aix-en-Provence (France); Sans, J.L. [PROMES CNRS 8521, Centre Felix Trombe, BP5, Odeillo, F-66125 Font Romeu (France); Scheer, E. [DGA/DET/CEP/LOT/EHF, 10 rue des fours solaires, BP 6, F-66125 Font Romeu (France); Berghmans, F. [SCK.CEN, EURATOM Ass. Belgium, Boeretang 200, B-2400 Mol (Belgium); Decreton, M. [SCK.CEN, EURATOM Ass. Belgium, Boeretang 200, B-2400 Mol (Belgium)

    2007-06-15

    In the course of the development of a concept for a spectrally resolving thermography diagnostic for the ITER divertor using optical fibres experimental development work has been carried out in three different areas. Firstly ZrF{sub 4} fibres and hollow fibres (silica capillaries with internal AG/AgJ coating) were tested in a Co{sup 60} irradiation facility under {gamma} irradiation up to doses of 5 kGy and 27 kGy, respectively. The ZrF{sub 4} fibres suffered more radiation induced degradation (>1 db/m) then the hollow fibres (0-0.4 db/m). Secondly multi-colour pyroreflectometry is being developed towards tokamak applicability. The emissivity and temperature of tungsten samples were measured in the range of 700-1500 {sup o}C. The angular working range for off normal observation of the method was 20-30{sup o}. The working distance of the method has been be increased from cm to the m range. Finally, encouraging preliminary results have been obtained concerning the application of pulsed and modulated active thermography.

  15. ITER coils insulation R and D program

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, R.F.; Sugimoto, M.; Osaki, O.; Fujioka, T.; Korsunsky, V.; Reed, R.P.; Katheder, H.; Broadbent, A.

    1995-12-31

    The ITER coil insulation systems are required for operating voltages up to 10 KV and to support shear and normal compression loads through the winding pack. Manufacturing considerations and nuclear radiation resistance also influence the choice of suitable systems. A screening program of candidate systems is being conducted in stages. The first stage is reported in this paper. Present R and D data based on small samples indicate a static shear strength of about 85 MPa for a glass or alumina and epoxy resin vacuum pressure impregnation system and 50 MPa for a pre-impregnated glass/epoxy resin system with polyimide interleaved at a temperature of 4K. The preliminary irradiation results show that coating the steel surface with inorganic materials such as Al{sub 2}O{sub 3} or ZrO{sub 2}/8 Y{sub 2}O{sub 3} is beneficial in increasing the radiation resistance as far as shear strength is concerned. In addition Tetrafunctional epoxy (TGDM) systems appear to be more radiation resistant than Diglycidyl Ether of Bisphenol-A (DGEBA) systems. Further R and D work will focus on prototypical samples to continue evaluation of the performance of the insulation systems.

  16. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

    The magnet is fully stopped and at room temperature. The maintenance works and consolidation activities on the magnet sub-systems are progressing. To consolidate the cryogenic installation, two redundant helium compressors will be installed as ‘hot spares’, to avoid the risk of a magnet downtime in case of a major failure of a compressor unit during operation. The screw compressors, their motors, the mechanical couplings and the concrete blocks are already available and stored at P5. The metallic structure used to access the existing compressors in SH5 will be modified to allow the installation of the two redundant ones. The plan is to finish the installation and commissioning of the hot spare compressors before the summer 2014. In the meantime, a bypass on the high-pressure helium piping will be installed for the connection of a helium drier unit later during the Long Shutdown 1, keeping this installation out of the schedule critical path. A proposal is now being prepared for the con...

  17. MAGNET

    CERN Multimedia

    B. Curé

    MAGNET During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bough...

  18. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet worked very well at 3.8 T as expected, despite a technical issue that manifested twice in the cryogenics since June. All the other magnet sub-systems worked without flaw. The issue in the cryogenics was with the cold box: it could be observed that the cold box was getting progressively blocked, due to some residual humidity and air accumulating in the first thermal exchanger and in the adsorber at 65 K. This was later confirmed by the analysis during the regeneration phases. An increase in the temperature difference between the helium inlet and outlet across the heat exchanger and a pressure drop increase on the filter of the adsorber were observed. The consequence was a reduction of the helium flow, first compensated by the automatic opening of the regulation valves. But once they were fully opened, the flow and refrigeration power reduced as a consequence. In such a situation, the liquid helium level in the helium Dewar decreased, eventually causing a ramp down of the magnet current and a field...

  19. MAGNET

    CERN Multimedia

    Benoit Curé.

    The magnet operation restarted end of June this year. Quick routine checks of the magnet sub-systems were performed at low current before starting the ramps up to higher field. It appeared clearly that the end of the field ramp down to zero was too long to be compatible with the detector commissioning and operations plans. It was decided to perform an upgrade to keep the ramp down from 3.8T to zero within 4 hours. On July 10th, when a field of 1.5T was reached, small movements were observed in the forward region support table and it was decided to fix this problem before going to higher field. At the end of July the ramps could be resumed. On July 28th, the field was at 3.8T and the summer CRAFT exercise could start. This run in August went smoothly until a general CERN wide power cut took place on August 3rd, due to an insulation fault on the high voltage network outside point 5. It affected the magnet powering electrical circuit, as it caused the opening of the main circuit breakers, resulting in a fast du...

  20. Series Supply of Cryogenic Venturi Flowmeters for the ITER Project

    Science.gov (United States)

    André, J.; Poncet, J. M.; Ercolani, E.; Clayton, N.; Journeaux, J. Y.

    2015-12-01

    In the framework of the ITER project, the CEA-SBT has been contracted to supply 277 venturi tube flowmeters to measure the distribution of helium in the superconducting magnets of the ITER tokamak. Six sizes of venturi tube have been designed so as to span a measurable helium flowrate range from 0.1 g/s to 400g/s. They operate, in nominal conditions, either at 4K or at 300K, and in a nuclear and magnetic environment. Due to the cryogenic conditions and the large number of venturi tubes to be supplied, an individual calibration of each venturi tube would be too expensive and time consuming. Studies have been performed to produce a design which will offer high repeatability in manufacture, reduce the geometrical uncertainties and improve the final helium flowrate measurement accuracy. On the instrumentation side, technologies for differential and absolute pressure transducers able to operate in applied magnetic fields need to be identified and validated. The complete helium mass flow measurement chain will be qualified in four test benches: - A helium loop at room temperature to insure the qualification of a statistically relevant number of venturi tubes operating at 300K.- A supercritical helium loop for the qualification of venturi tubes operating at cryogenic temperature (a modification to the HELIOS test bench). - A dedicated vacuum vessel to check the helium leak tightness of all the venturi tubes. - A magnetic test bench to qualify different technologies of pressure transducer in applied magnetic fields up to 100mT.

  1. Matlab modeling of ITER CODAC

    Energy Technology Data Exchange (ETDEWEB)

    Pangione, L. [Associazione Euratom/ENEA Ssulla Fusione, Centro Ricerche Frascati, CP 65, 00044 Frascati, Roma (Italy)], E-mail: pangione@frascati.enea.it; Lister, J.B. [CRPP-EPFL, Association EURATOM-Suisse, Station 13, 1015 Lausanne (Switzerland)

    2008-04-15

    The ITER CODAC (COntrol, Data Access and Communication) conceptual design resulted from 2 years of activity. One result was a proposed functional partitioning of CODAC into different CODAC Systems, each of them partitioned into other CODAC Systems. Considering the large size of this project, simple use of human language assisted by figures would certainly be ineffective in creating an unambiguous description of all interactions and all relations between these Systems. Moreover, the underlying design is resident in the mind of the designers, who must consider all possible situations that could happen to each system. There is therefore a need to model the whole of CODAC with a clear and preferably graphical method, which allows the designers to verify the correctness and the consistency of their project. The aim of this paper is to describe the work started on ITER CODAC modeling using Matlab/Simulink. The main feature of this tool is the possibility of having a simple, graphical, intuitive representation of a complex system and ultimately to run a numerical simulation of it. Using Matlab/Simulink, each CODAC System was represented in a graphical and intuitive form with its relations and interactions through the definition of a small number of simple rules. In a Simulink diagram, each system was represented as a 'black box', both containing, and connected to, a number of other systems. In this way it is possible to move vertically between systems on different levels, to show the relation of membership, or horizontally to analyse the information exchange between systems at the same level. This process can be iterated, starting from a global diagram, in which only CODAC appears with the Plant Systems and the external sites, and going deeper down to the mathematical model of each CODAC system. The Matlab/Simulink features for simulating the whole top diagram encourage us to develop the idea of completing the functionalities of all systems in order to finally

  2. Iterative Goal Refinement for Robotics

    Science.gov (United States)

    2014-06-01

    Iterative Goal Refinement for Robotics Mark Roberts1, Swaroop Vattam1, Ronald Alford2, Bryan Auslander3, Justin Karneeb3, Matthew Molineaux3... robotics researchers and practitioners. We present a goal lifecycle and define a formal model for GR that (1) relates distinct disciplines concerning...researchers to collaborate in exploring this exciting frontier. 1. Introduction Robotic systems often act using incomplete models in environments

  3. Truncated States Obtained by Iteration

    Institute of Scientific and Technical Information of China (English)

    W.B.Cardoso; N.G.de Almeida

    2008-01-01

    We introduce the concept of truncated states obtained via iterative processes(TSI)and study its statistical features,making an analogy with dynamical systems theory(DST).As a specific example,we have studied TSI for the doubring and the logistic functions,which are standard functions in studying chaos.TSI for both the doubling and logistic functions exhibit certain similar patterns when their statistical features are compared from the point of view of DST.

  4. Radioactivity measurements of ITER materials using the TFTR D-T neutron field

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.; Abdou, M.A. [California Univ., Los Angeles, CA (United States). School of Engineering and Applied Science; Barnes, C.W. [Los Alamos National Lab., NM (United States); Kugel, H.W. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Loughlin, M.J. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-08-01

    The availability of high D-T fusion neutron yields at TFTR has provided a useful opportunity to directly measure D-T neutron-induced radioactivity in a realistic tokamak fusion reactor environment for materials of vital interest to ITER. These measurements are valuable for characterizing radioactivity in various ITER candidate materials. for validating complex neutron transport calculations, and for meeting fusion reactor licensing requirements. The radioactivity measurements at TFTR involve potential ITER materials including stainless steel 316, vanadium, titanium, chromium, silicon, iron, cobalt, nickel, molybdenum, aluminum, copper, zinc. zirconium, niobium, and tungsten. Small samples of these materials were irradiated close to the plasma and just outside the vacuum vessel wall of TFTR, locations of different neutron energy spectra. Saturation activities for both threshold and capture reactions were measured. Data from dosimetric reactions have been used to obtain preliminary neutron energy spectra. Spectra from the first wall were compared to calculations from ITER and to measurements from accelerator-based tests.

  5. Dynamic gadolinium-enhanced magnetic resonance urography for assessing drainage in dilated pelvicalyceal systems with moderate renal function: preliminary results and comparison with diuresis renography.

    Science.gov (United States)

    Chu, W C W; Lam, W W M; Chan, K W; Yeung, C K; Lee, K H; Sihoe, J D Y

    2004-04-01

    To evaluate the use of dynamic gadolinium diethylenetriaminepenta-acetic acid (DTPA)-enhanced magnetic resonance urography (Gd-MRU) for assessing kidneys with markedly dilated pelvicalyceal systems and impaired function. Eight children (mean age 30 months, sd 25) were assessed, diagnosed as having gross unilateral hydronephrosis with a mean (sd) anteroposterior renal pelvic diameter of 36 (7) mm and reduced (30-40%) renal function. Dynamic Gd-MRU was performed after the patients were pre-loaded with intravenous fluid and diuretics, and comprised a dynamic T1-weighted sequence after Gd-DTPA (0.1 mmol/kg body weight) was administered, with a time-intensity curve of each kidney produced. Drainage was diagnosed by a clearly declining time-intensity curve and direct visualization of contrast medium within the ureter in several frames. High-grade or complete obstruction was diagnosed when drainage of contrast medium could not be detected. Gd-MRU results were compared with diuresis radionuclide (mercapto-acetyltriglycine, MAG3) renography within the same week. Unobstructive units detected by Gd-MRU were treated conservatively with a close follow-up by ultrasonography and radionuclide studies. Diuresis MAG3 renography showed drainage in three dilated units and poor washout in five; in contrast, Gd-MRU showed drainage in seven dilated systems (three showed poor washout by MAG3), and obstruction in the remaining case. The unobstructed units detected by MRU under conservative treatment thus showed no further deterioration of renal function or progressive hydronephrosis in the subsequent follow-up (mean 18 months, range 15-23). These preliminary results suggest that dynamic Gd-MRU is a useful noninvasive imaging method in distinguishing obstructive from unobstructive dilated systems, particularly in patients with hydronephrosis and reduced renal function.

  6. Iterative wavelet thresholding for rapid MRI reconstruction

    Science.gov (United States)

    Kayvanrad, Mohammad H.; McKenzie, Charles A.; Peters, Terry M.

    2011-03-01

    According to the developments in the field of compressed sampling and and sparse recovery, one might take advantage of the sparsity of an object, as an additional a priori knowledge about the object, to reconstruct it from fewer samples than that needed by the traditional sampling strategies. Since most magnetic resonance (MR) images are sparse in some domain, in this work we consider the problem of MR reconstruction and how one could apply this idea to accelerate the process of MR image/map acquisition. In particular, based on the Paupolis-Gerchgerg algorithm, an iterative thresholding algorithm for reconstruction of MR images from limited k-space observations is proposed. The proposed method takes advantage of the sparsity of most MR images in the wavelet domain. Initializing with a minimum-energy reconstruction, the object of interest is reconstructed by going through a sequence of thresholding and recovery iterations. Furthermore, MR studies often involve acquisition of multiple images in time that are highly correlated. This correlation can be used as additional knowledge on the object beside the sparsity to further reduce the reconstruction time. The performance of the proposed algorithms is experimentally evaluated and compared to other state-of-the-art methods. In particular, we show that the quality of reconstruction is increased compared to total variation (TV) regularization, and the conventional Papoulis-Gerchberg algorithm both in the absence and in the presence of noise. Also, phantom experiments show good accuracy in the reconstruction of relaxation maps from a set of highly undersampled k-space observations.

  7. Iterative methods for mixed finite element equations

    Science.gov (United States)

    Nakazawa, S.; Nagtegaal, J. C.; Zienkiewicz, O. C.

    1985-01-01

    Iterative strategies for the solution of indefinite system of equations arising from the mixed finite element method are investigated in this paper with application to linear and nonlinear problems in solid and structural mechanics. The augmented Hu-Washizu form is derived, which is then utilized to construct a family of iterative algorithms using the displacement method as the preconditioner. Two types of iterative algorithms are implemented. Those are: constant metric iterations which does not involve the update of preconditioner; variable metric iterations, in which the inverse of the preconditioning matrix is updated. A series of numerical experiments is conducted to evaluate the numerical performance with application to linear and nonlinear model problems.

  8. FAST: A European ITER satellite experiment in the view of DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Crisanti, F., E-mail: Crisanti@frascati.enea.it [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy); Cucchiaro, A. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy); Albanese, R.; Artaserse, G. [Assoc. Euratom-ENEA-CREATE, Univ. Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Baruzzo, M.; Bolzonella, T. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Brolatti, G.; Calabro, G.; Crescenzi, F.; Coletti, R.; Costa, P.; Corte, A. della; Di Zenobio, A.; Frosi, P. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy); Harting, D. [Ins. Plasmaphysik, Forschungszentrum, Euratom Ass., Tril. Euregio Cluster, D-52425 Julich (Germany); Taroni, L. Lauro [New College, Oxford OX1 3BN (United Kingdom); Maddaluno, G. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy); Marcuzzi, D. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Maviglia, F. [Assoc. Euratom-ENEA-CREATE, Univ. Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Muzzi, L. [Associazione Euratom/ENEA sulla Fusione, CP 65-00044 Frascati, Rome (Italy)

    2011-10-15

    Fusion Advanced Studies Torus (FAST) aims to contribute to the exploitation of ITER and to explore innovative DEMO technology. FAST has been designed to study, in an integrated scenario: (a) relevant plasma-wall interaction problems, with a large power load (P/R {approx} 22 MW/m; P/R{sup 2} {approx} 12 MW/m{sup 2}) and with a full metallic wall; (b) to tackle operational problems in regimes with relevant fusion parameters; (c) to investigate the non-linear dynamics of fast particles (alpha like) in burning plasmas. FAST will operate on a wide parameters range, namely in high performance H-mode (BT {approx} 8.5 T; IP {approx} 8 MA) as well as in advanced Tokamak operation up to full non-inductive current scenario (IP {approx} 2 MA). The main heating is based on 30 MW ICRH, but the ports have been designed to allocate up to 20 MW of 1 MeV NNBI. Helium gas at 30 K is used for cooling of the full machine, a preliminary analysis shows the possibility of realizing FAST with a complete superconductor set of coils. An innovative active system is under development to reduce and to control the magnetic ripple. Tungsten (W) or liquid lithium (L-Li) has been chosen for the divertor material plates and the code EDGE2D has been used to optimize the divertor geometry.

  9. Real-time cardiac magnetic resonance cine imaging with sparse sampling and iterative reconstruction for left-ventricular measures: Comparison with gold-standard segmented steady-state free precession.

    Science.gov (United States)

    Camargo, Gabriel C; Erthal, Fernanda; Sabioni, Leticia; Penna, Filipe; Strecker, Ralph; Schmidt, Michaela; Zenge, Michael O; Lima, Ronaldo de S L; Gottlieb, Ilan

    2017-05-01

    Segmented cine imaging with a steady-state free-precession sequence (Cine-SSFP) is currently the gold standard technique for measuring ventricular volumes and mass, but due to multi breath-hold (BH) requirements, it is prone to misalignment of consecutive slices, time consuming and dependent on respiratory capacity. Real-time cine avoids those limitations, but poor spatial and temporal resolution of conventional sequences has prevented its routine application. We sought to examine the accuracy and feasibility of a newly developed real-time sequence with aggressive under-sampling of k-space using sparse sampling and iterative reconstruction (Cine-RT). Stacks of short-axis cines were acquired covering both ventricles in a 1.5T system using gold standard Cine-SSFP and Cine-RT. Acquisition parameters for Cine-SSFP were: acquisition matrix of 224×196, temporal resolution of 39ms, retrospective gating, with an average of 8 heartbeats per slice and 1-2 slices/BH. For Cine-RT: acquisition matrix of 224×196, sparse sampling net acceleration factor of 11.3, temporal resolution of 41ms, prospective gating, real-time acquisition of 1 heart-beat/slice and all slices in one BH. LV contours were drawn at end diastole and systole to derive LV volumes and mass. Forty-one consecutive patients (15 male; 41±17years) in sinus rhythm were successfully included. All images from Cine-SSFP and Cine-RT were considered to have excellent quality. Cine-RT-derived LV volumes and mass were slightly underestimated but strongly correlated with gold standard Cine-SSFP. Inter- and intra-observer analysis presented similar results between both sequences. Cine-RT featuring sparse sampling and iterative reconstruction can achieve spatial and temporal resolution equivalent to Cine-SSFP, providing excellent image quality, with similar precision measurements and highly correlated and only slightly underestimated volume and mass values. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. An Equivalent Source Method for Modelling the Lithospheric Magnetic Field Using Satellite and Airborne Magnetic Data

    Science.gov (United States)

    Kother, L. K.; Hammer, M. D.; Finlay, C. C.; Olsen, N.

    2014-12-01

    We present a technique for modelling the lithospheric magnetic field based on estimation of equivalent potential field sources. As a first demonstration we present an application to magnetic field measurements made by the CHAMP satellite during the period 2009-2010. Three component vector field data are utilized at all latitudes. Estimates of core and large-scale magnetospheric sources are removed from the satellite measurements using the CHAOS-4 model. Quiet-time and night-side data selection criteria are also employed to minimize the influence of the ionospheric field. The model for the remaining lithospheric magnetic field consists of magnetic point sources (monopoles) arranged in an icosahedron grid with an increasing grid resolution towards the airborne survey area. The corresponding source values are estimated using an iteratively reweighted least squares algorithm that includes model regularization (either quadratic or maximum entropy) and Huber weighting. Data error covariance matrices are implemented, accounting for the dependence of data error variances on quasi-dipole latitudes. Results show good consistency with the CM5 and MF7 models for spherical harmonic degrees up to n = 95. Advantages of the equivalent source method include its local nature and the ease of transforming to spherical harmonics when needed. The method can also be applied in local, high resolution, investigations of the lithospheric magnetic field, for example where suitable aeromagnetic data is available. To illustrate this possibility, we present preliminary results from a case study combining satellite measurements and local airborne scalar magnetic measurements of the Norwegian coastline.

  11. Meromorphic iterative roots of linear fractional functions

    Institute of Scientific and Technical Information of China (English)

    SHI YongGuo; CHEN Li

    2009-01-01

    Iterative root problem can be regarded as a weak version of the problem of embedding a homeomorphism into a flow. There are many results on iterative roots of monotone functions. However, this problem gets more difficult in non-monotone cases. Therefore, it is interesting to find iterative roots of linear fractional functions (abbreviated as LFFs), a class of non-monotone functions on R. In this paper, iterative roots of LFFs are studied on C. An equivalence between the iterative functional equation for non-constant LFFs and the matrix equation is given. By means of a method of finding matrix roots, general formulae of all meromorphic iterative roots of LFFs are obtained and the precise number of roots is also determined in various cases. As applications, we present all meromorphic iterative roots for functions z and 1/z.

  12. Performance bounds for Lambda Policy Iteration

    CERN Document Server

    Scherrer, Bruno

    2007-01-01

    We consider the discrete-time infinite-horizon discounted stationary optimal control problem formalized by Markov Decision Processes. We study Lambda Policy Iteration, a family of algorithms parameterized by lambda, originally introduced by Ioffe and Bertsekas. Lambda Policy Iteration generalizes the standard algorithms Value Iteration and Policy Iteration, and has some connections with TD(Lambda) introduced by Sutton & Barto. We deepen the original theory developped by Ioffe and Bertsekas by providing convergence rate bounds which generalize standard bounds for Value Iteration described for instance by Puterman. We also develop the theory of this algorithm when it is used in an approximate form. Doing so, we extend and unify the separate analyses developped by Munos for Approximate Value Iteration and Approximate Policy Iteration.

  13. MAGNET

    CERN Multimedia

    Benoit Curé

    The magnet subsystems resumed operation early this spring. The vacuum pumping was restarted mid March, and the cryogenic power plant was restarted on March 30th. Three and a half weeks later, the magnet was at 4.5 K. The vacuum pumping system is performing well. One of the newly installed vacuum gauges had to be replaced at the end of the cool-down phase, as the values indicated were not coherent with the other pressure measurements. The correction had to be implemented quickly to be sure no helium leak could be at the origin of this anomaly. The pressure measurements have been stable and coherent since the change. The cryogenics worked well, and the cool-down went quite smoothly, without any particular difficulty. The automated start of the turbines had to be fine-tuned to get a smooth transition, as it was observed that the cooling power delivered by the turbines was slightly higher than needed, causing the cold box to stop automatically. This had no consequence as the cold box safety system acts to keep ...

  14. MAGNET

    CERN Multimedia

    B. Curé

    During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bought. Th...

  15. Qualification of the Joints for the ITER Central Solenoid

    Energy Technology Data Exchange (ETDEWEB)

    Martovetsky, N; Berryhill, A; Kenney, S

    2011-09-01

    The ITER Central Solenoid has 36 interpancake joints, 12 bus joints, and 12 feeder joints in the magnet. The joints are required to have resistance below 4 nOhm at 45 kA at 4.5 K. The US ITER Project Office developed two different types of interpancake joints with some variations in details in order to find a better design, qualify the joints, and establish a fabrication process. We built and tested four samples of the sintered joints and two samples with butt-bonded joints (a total of eight joints). Both designs met the specifications. Results of the joint development, test results, and selection of the baseline design are presented and discussed in the paper. The ITER Central Solenoid (CS) consists of six modules. Each module is composed of six wound hexapancakes and one quadrapancake. The multipancakes are connected electrically and hydraulically by in-line interpancake joints. The joints are located at the outside diameter (OD) of the module. Cable in conduit conductor (CICC) high-current joints are critical elements in the CICC magnets. In addition to low resistivity, the CS joints must fit a space envelope equivalent to the regular conductor cross section and must have low hydraulic impedance and enough structural strength to withstand the hoop and compressive forces during operation, including cycling. This paper is the continuation of the work reported on the intermodule joints.

  16. Seismic analysis of ITER fourth PF (Poloidal Field Coil) feeder

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Sumei, E-mail: smliu@ipp.ac.cn [School of Engineering, Anhui Agricultural University, Hefei 230036 (China); Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China); Chen, Wei [School of Engineering, Anhui Agricultural University, Hefei 230036 (China); Song, Yuntao; Ni, Xiaojun; Wang, Zhongwei [Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China); Chen, Yonghua; Gong, Chenyu [Magnet Division, TKM, ITER Organization, Route de Vinon sur Verdon, 13115 St. Paul Lez Durance (France)

    2014-10-15

    The ITER feeder systems connect the ITER magnet systems located inside the main cryostat to the cryo-plant, power-supply and control system interfaces outside the cryostat. The main purpose of the feeders is to convey the cryogenic supply and electrical power to the coils as well as house the instrumentation wiring. The PF busbar which carries 52 kA current will suffer from high Lorentz force due to the background magnetic field inspired by the coils and the self-field between every pair of busbars. Except their mechanical strength and thermal insulation performance must be achieved, the dynamic mechanism on PF structure should be assessed. This paper presents the simulation and seismic analysis on ITER 4th PF feeder including the Coil Terminal Box and S-bend Box (CTB and SBB), the Cryostat Feed-through (CFT), the In-Cryostat-Feeder (ICF), especially for the ground supports and main outer-tube firstly. This analysis aims to study seismic resistance on system design under local seismograms with floor response spectrum, the structural response vibration mode and response duration results of displacement, membrane stress, and bending stress on structure under different directions actuating signals were obtained by using the single-seismic spectrum analysis and Dead Weight analysis respectively. Based on the simulative and analytical results, the system seismic resistance and the integrity of the support structure in the 4th PF feeder have been studied and the detail design confirmed.

  17. Beryllium in the ITER blanket

    Energy Technology Data Exchange (ETDEWEB)

    Billone, M.C.

    1995-01-01

    This paper consists of viewgraphs used in a presentation on the application of beryllium in breeding blankets for ITER and JET. The paper brings together data on the physical, thermal, mechanical, and chemical properties of beryllium and beryllium oxide for this type of application, as well as issues of compatibility with construction materials, and irradiation experience. It includes the results from testing programs carried out to arrive at some of the information, including fabrication work, irradiation experiments, and sample tests performed both in and out of the irradiation piles.

  18. Capabilities of the ITER Electron Cyclotron Equatorial Launcher for Heating and Current Drive

    Directory of Open Access Journals (Sweden)

    Ramponi G.

    2012-09-01

    Full Text Available The ITER Electron Cyclotron Equatorial Launcher is designed to be one of the heating systems to assist and sustain the development of various ITER plasma scenarios starting with the very first plasma operation. Here the capabilities for Heating and Current Drive of this system are reviewed. In particular, the optimum launching conditions are investigated for two scenarios at burn, comparing toroidal and poloidal steering options. Then, the EC capabilities are investigated for different plasma parameters corresponding to various phases of the ITER plasma discharge, from current ramp-up up to burn, and for a wide range of magnetic field, focusing in particular on the EC potential for heating and for L to H-mode assist. It is found that the EC system can contribute to a wide range of heating scenarios during the ramp-up of the magnetic field, significantly increasing the applicable range as a function of magnetic field.

  19. IHadoop: Asynchronous iterations for MapReduce

    KAUST Repository

    Elnikety, Eslam Mohamed Ibrahim

    2011-11-01

    MapReduce is a distributed programming frame-work designed to ease the development of scalable data-intensive applications for large clusters of commodity machines. Most machine learning and data mining applications involve iterative computations over large datasets, such as the Web hyperlink structures and social network graphs. Yet, the MapReduce model does not efficiently support this important class of applications. The architecture of MapReduce, most critically its dataflow techniques and task scheduling, is completely unaware of the nature of iterative applications; tasks are scheduled according to a policy that optimizes the execution for a single iteration which wastes bandwidth, I/O, and CPU cycles when compared with an optimal execution for a consecutive set of iterations. This work presents iHadoop, a modified MapReduce model, and an associated implementation, optimized for iterative computations. The iHadoop model schedules iterations asynchronously. It connects the output of one iteration to the next, allowing both to process their data concurrently. iHadoop\\'s task scheduler exploits inter-iteration data locality by scheduling tasks that exhibit a producer/consumer relation on the same physical machine allowing a fast local data transfer. For those iterative applications that require satisfying certain criteria before termination, iHadoop runs the check concurrently during the execution of the subsequent iteration to further reduce the application\\'s latency. This paper also describes our implementation of the iHadoop model, and evaluates its performance against Hadoop, the widely used open source implementation of MapReduce. Experiments using different data analysis applications over real-world and synthetic datasets show that iHadoop performs better than Hadoop for iterative algorithms, reducing execution time of iterative applications by 25% on average. Furthermore, integrating iHadoop with HaLoop, a variant Hadoop implementation that caches

  20. Iterative LQG Controller Design Through Closed-Loop Identification

    Science.gov (United States)

    Hsiao, Min-Hung; Huang, Jen-Kuang; Cox, David E.

    1996-01-01

    This paper presents an iterative Linear Quadratic Gaussian (LQG) controller design approach for a linear stochastic system with an uncertain open-loop model and unknown noise statistics. This approach consists of closed-loop identification and controller redesign cycles. In each cycle, the closed-loop identification method is used to identify an open-loop model and a steady-state Kalman filter gain from closed-loop input/output test data obtained by using a feedback LQG controller designed from the previous cycle. Then the identified open-loop model is used to redesign the state feedback. The state feedback and the identified Kalman filter gain are used to form an updated LQC controller for the next cycle. This iterative process continues until the updated controller converges. The proposed controller design is demonstrated by numerical simulations and experiments on a highly unstable large-gap magnetic suspension system.

  1. Conceptual design of the ITER fast-ion loss detector

    Science.gov (United States)

    Garcia-Munoz, M.; Kocan, M.; Ayllon-Guerola, J.; Bertalot, L.; Bonnet, Y.; Casal, N.; Galdon, J.; Garcia Lopez, J.; Giacomin, T.; Gonzalez-Martin, J.; Gunn, J. P.; Jimenez-Ramos, M. C.; Kiptily, V.; Pinches, S. D.; Rodriguez-Ramos, M.; Reichle, R.; Rivero-Rodriguez, J. F.; Sanchis-Sanchez, L.; Snicker, A.; Vayakis, G.; Veshchev, E.; Vorpahl, Ch.; Walsh, M.; Walton, R.

    2016-11-01

    A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ˜5° might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ˜11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.

  2. Detailed 3-D nuclear analysis of ITER outboard blanket modules

    Energy Technology Data Exchange (ETDEWEB)

    Bohm, Tim, E-mail: tdbohm@wisc.edu [Fusion Technology Institute, University of Wisconsin-Madison, Madison, WI (United States); Davis, Andrew; Sawan, Mohamed; Marriott, Edward; Wilson, Paul [Fusion Technology Institute, University of Wisconsin-Madison, Madison, WI (United States); Ulrickson, Michael; Bullock, James [Formerly, Fusion Technology, Sandia National Laboratories, Albuquerque, NM (United States)

    2015-10-15

    Highlights: • Nuclear analysis was performed on detailed CAD models placed in a 40 degree model of ITER. • The regions examined include BM09, the upper ELM coil region (BM11–13), the neutral beam (NB) region (BM13–16), and BM18. • The results show that VV nuclear heating exceeds limits in the NB and upper ELM coil regions. • The results also show that the level of He production in parts of BM18 exceeds limits. • These calculations are being used to modify the design of the ITER blanket modules. - Abstract: In the ITER design, the blanket modules (BM) provide thermal and nuclear shielding for the vacuum vessel (VV), magnets, and other components. We used the CAD based DAG-MCNP5 transport code to analyze detailed models inserted into a 40 degree partially homogenized ITER global model. The regions analyzed include BM09, BM16 near the heating neutral beam injection (HNB) region, BM11–13 near the upper ELM coil region, and BM18. For the BM16 HNB region, the VV nuclear heating behind the NB region exceeds the design limit by up to 80%. For the BM11–13 region, the nuclear heating of the VV exceeds the design limit by up to 45%. For BM18, the results show that He production does not meet the limit necessary for re-welding. The results presented in this work are being used by the ITER Organization Blanket and Tokamak Integration groups to modify the BM design in the cases where limits are exceeded.

  3. The anatomy of a cinder cone: preliminary paleomagnetic, rock magnetic, structural, and petrologic data from the La Cienega volcano, Cerros del Rio volcanic field, northern New Mexico

    Science.gov (United States)

    Petronis, M. S.; Foucher, M.; Lineline, J.; Van Wyk de Vries, B.

    2011-12-01

    The Cerros del Rio volcanic field is one of several middle Pliocene to Pleistocene basaltic volcanic fields of the axial Rio Grande Rift in central and northern New Mexico. It is a monogenetic volcanic field that comprises about 60 cinder-spatter cones, occupies ~ 700 km2, and ranges in age from 2.7 Ma to 1.1 Ma. Eruptive centers are typically central vent volcanoes, ranging from low-relief shields to steep-sided, breached cinder and spatter cone remnants. They represent short eruptive events that likely were derived from rapidly evolving reservoir-conduit systems. Mining activity has exposed the volcanic plumbing system of the Cienega Mine cinder cone, just west of Santa Fe, NM. Here, geologists from France and USA have been investigating the exposed roots of this eviscerated Pliocene volcano to investigate magma conduit geometry, magma flow structures, and eruption patterns. We are testing models for magma transport and volcano construction using a variety of field and laboratory tools. Common models of volcanic construction envision the magma feeder as a dike or pipe-like conduit transporting molten rock from a deep reservoir to the eruptive vent. We posit that small volcanic pluming systems are inherently more complex and actually involve numerous feeder geometries throughout the volcano lifespan. Our preliminary work suggests that the simple exteriors of some cinder cones hide a long life and complex history, both of which would change the appreciation of the related volcanic hazards in active systems. The Cienega Mine cinder cone consists of several meter- to decimeter-wide intrusions that connect to eruptive centers. These intrusions show a continuity of brittle to ductile structures from their margins to interiors. We have collected samples across each intrusion as well as along strike for anisotropy of magnetic susceptibility (AMS) and petrographic analysis in order to establish magma flow patterns. AMS results yield a remarkably consistent dataset that

  4. Status of US ITER Diagnostics

    Science.gov (United States)

    Stratton, B.; Delgado-Aparicio, L.; Hill, K.; Johnson, D.; Pablant, N.; Barnsley, R.; Bertschinger, G.; de Bock, M. F. M.; Reichle, R.; Udintsev, V. S.; Watts, C.; Austin, M.; Phillips, P.; Beiersdorfer, P.; Biewer, T. M.; Hanson, G.; Klepper, C. C.; Carlstrom, T.; van Zeeland, M. A.; Brower, D.; Doyle, E.; Peebles, A.; Ellis, R.; Levinton, F.; Yuh, H.

    2013-10-01

    The US is providing 7 diagnostics to ITER: the Upper Visible/IR cameras, the Low Field Side Reflectometer, the Motional Stark Effect diagnostic, the Electron Cyclotron Emission diagnostic, the Toroidal Interferometer/Polarimeter, the Core Imaging X-Ray Spectrometer, and the Diagnostic Residual Gas Analyzer. The front-end components of these systems must operate with high reliability in conditions of long pulse operation, high neutron and gamma fluxes, very high neutron fluence, significant neutron heating (up to 7 MW/m3) , large radiant and charge exchange heat flux (0.35 MW/m2) , and high electromagnetic loads. Opportunities for repair and maintenance of these components will be limited. These conditions lead to significant challenges for the design of the diagnostics. Space constraints, provision of adequate radiation shielding, and development of repair and maintenance strategies are challenges for diagnostic integration into the port plugs that also affect diagnostic design. The current status of design of the US ITER diagnostics is presented and R&D needs are identified. Supported by DOE contracts DE-AC02-09CH11466 (PPPL) and DE-AC05-00OR22725 (UT-Battelle, LLC).

  5. ITER Port Interspace Pressure Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Carbajo, Juan J [ORNL; Van Hove, Walter A [ORNL

    2016-01-01

    The ITER Vacuum Vessel (VV) is equipped with 54 access ports. Each of these ports has an opening in the bioshield that communicates with a dedicated port cell. During Tokamak operation, the bioshield opening must be closed with a concrete plug to shield the radiation coming from the plasma. This port plug separates the port cell into a Port Interspace (between VV closure lid and Port Plug) on the inner side and the Port Cell on the outer side. This paper presents calculations of pressures and temperatures in the ITER (Ref. 1) Port Interspace after a double-ended guillotine break (DEGB) of a pipe of the Tokamak Cooling Water System (TCWS) with high temperature water. It is assumed that this DEGB occurs during the worst possible conditions, which are during water baking operation, with water at a temperature of 523 K (250 C) and at a pressure of 4.4 MPa. These conditions are more severe than during normal Tokamak operation, with the water at 398 K (125 C) and 2 MPa. Two computer codes are employed in these calculations: RELAP5-3D Version 4.2.1 (Ref. 2) to calculate the blowdown releases from the pipe break, and MELCOR, Version 1.8.6 (Ref. 3) to calculate the pressures and temperatures in the Port Interspace. A sensitivity study has been performed to optimize some flow areas.

  6. Iterated Stretching of Viscoelastic Jets

    Science.gov (United States)

    Chang, Hsueh-Chia; Demekhin, Evgeny A.; Kalaidin, Evgeny

    1999-01-01

    We examine, with asymptotic analysis and numerical simulation, the iterated stretching dynamics of FENE and Oldroyd-B jets of initial radius r(sub 0), shear viscosity nu, Weissenberg number We, retardation number S, and capillary number Ca. The usual Rayleigh instability stretches the local uniaxial extensional flow region near a minimum in jet radius into a primary filament of radius [Ca(1 - S)/ We](sup 1/2)r(sub 0) between two beads. The strain-rate within the filament remains constant while its radius (elastic stress) decreases (increases) exponentially in time with a long elastic relaxation time 3We(r(sup 2, sub 0)/nu). Instabilities convected from the bead relieve the tension at the necks during this slow elastic drainage and trigger a filament recoil. Secondary filaments then form at the necks from the resulting stretching. This iterated stretching is predicted to occur successively to generate high-generation filaments of radius r(sub n), (r(sub n)/r(sub 0)) = square root of 2[r(sub n-1)/r(sub 0)](sup 3/2) until finite-extensibility effects set in.

  7. Impact of risk analysis on ITER nuclear buildings layout

    Energy Technology Data Exchange (ETDEWEB)

    Sabathe, Laurent [AREVA NP SAS, 10 rue Juliette Recamier, 69456 Lyon Cedex 06 (France)], E-mail: laurent.sabathe@areva.com; Lignini, Franck [AREVA NP SAS, 10 rue Juliette Recamier, 69456 Lyon Cedex 06 (France)], E-mail: franck.lignini@areva.com; Rodriguez-Rodrigo, Lina [EFDA-CSU Barcelona and Asociacion EURATOM-CIEMAT para Fusion, 08019 Barcelona (Spain); Uzan-Elbez, Joelle [Agence ITER-France, Cadarache, St Paul Lez Durance F-13108 (France); Girard, Jean-Philippe [ITER-JWS, Cadarache, St Paul Lez Durance F-13108 (France)

    2007-10-15

    The internal layout of ITER nuclear buildings (Tokamak, Tritium, Hot cell and Radwaste buildings) is the result of an iterative process. Notwithstanding civil engineering requirements, technical and functional requirements for the processes housed in the buildings, the internal layout must also take into account safety requirements and workers protection requirements in normal, incidental and accidental conditions. Potential hazards and constraints result in the definition of various zonings. Each room is classified depending on the level of the risks induced by normal and incidental or accidental conditions: - radiological exposure to tritium, and activated products {yields} radiological zoning; - exposure to beryllium (vacuum vessel blankets) {yields} beryllium zoning; - exposure to electromagnetic fields during plasma shots {yields} electromagnetic zoning; - fire hazard: fire compartmentalization; {center_dot}explosion hazard: anti-blast zoning; - waste treatment {yields} waste zoning. Prevention of common mode failure due to internal hazards (fire, flooding, load drop...) for redundant safety important components is also taken into account by geographical separation or by installation of protections between components (either in the same room or preferably when possible by segregation in different rooms). The designer has also taken into account access requirements to equipments and circulation rules for personal, material and substances in ITER nuclear buildings. Risk analyses are performed in the Preliminary Safety Report in order to demonstrate that the layout of ITER nuclear buildings allows meeting the safety objectives and takes into account the requirements associated with the zonings classifications and complies with the regulation. When necessary, modifications are implemented in the design. For example, recent layout modifications are been studied in the tritium building: utility rooms (electrical supply) were transferred outside the radiological

  8. MAGNET

    CERN Multimedia

    Benoit Curé

    2013-01-01

    Maintenance work and consolidation activities on the magnet cryogenics and its power distribution are progressing according to the schedules. The manufacturing of the two new helium compressor frame units has started. The frame units support the valves, all the sensors and the compressors with their motors. This activity is subcontracted. The final installation and the commissioning at CERN are scheduled for March–April 2014. The overhauls of existing cryogenics equipment (compressors, motors) are in progress. The reassembly of the components shall start in early 2014. The helium drier, to be installed on the high-pressure helium piping, has been ordered and will be delivered in the first trimester of 2014. The power distribution for the helium compressors in SH5 on the 3.3kV network is progressing. The 3.3kV switches, between each compressor and its hot spare compressor, are being installed, together with the power cables for the new compressors. The 3.3kV electrical switchboards in SE5 will ...

  9. MAGNET

    CERN Multimedia

    B. Curé

    The first phase of the commissioning ended in August by a triggered fast dump at 3T. All parameters were nominal, and the temperature recovery down to 4.5K was carried out in two days by the cryogenics. In September, series of ramps were achieved up to 3 and finally 3.8T, while checking thoroughly the detectors in the forward region, measuring any movement of and around the HF. After the incident of the LHC accelerator on September 19th, corrective actions could be undertaken in the forward region. When all these displacements were fully characterized and repetitive, with no sign of increments in displacement at each field ramp, it was possible to start the CRAFT, Cosmic Run at Four Tesla (which was in fact at 3.8T). The magnet was ramped up to 18.16kA and the 3 week run went smoothly, with only 4 interruptions: due to the VIP visits on 21st October during the LHC inauguration day; a water leak on the cooling demineralized water circuit, about 1 l/min, that triggered a stop of the cooling pumps, and resulte...

  10. Magnetic

    Science.gov (United States)

    Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.

    2015-06-01

    The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and magnetic data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.

  11. ITER-EDA physics design requirements and plasma performance assessments

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, N.A.; Galambos, J. [Oak Ridge National Lab., TN (United States); Wesley, J.; Boucher, D.; Perkins, F.; Post, D.; Putvinski, S. [ITER San Diego Joint Work Site, CA (United States)

    1996-07-01

    Physics design guidelines, plasma performance estimates, and sensitivity of performance to changes in physics assumptions are presented for the ITER-EDA Interim Design. The overall ITER device parameters have been derived from the performance goals using physics guidelines based on the physics R&D results. The ITER-EDA design has a single-null divertor configuration (divertor at the bottom) with a nominal plasma current of 21 MA, magnetic field of 5.68 T, major and minor radius of 8.14 m and 2.8 m, and a plasma elongation (at the 95% flux surface) of {approximately}1.6 that produces a nominal fusion power of {approximately}1.5 GW for an ignited burn pulse length of {ge}1000 s. The assessments have shown that ignition at 1.5 GW of fusion power can be sustained in ITER for 1000 s given present extrapolations of H-mode confinement ({tau}{sub E} = 0.85 {times} {tau}{sub ITER93H}), helium exhaust ({tau}*{sub He}/{tau}{sub E} = 10), representative plasma impurities (n{sub Be}/n{sub e} = 2%), and beta limit [{beta}{sub N} = {beta}(%)/(I/aB) {le} 2.5]. The provision of 100 MW of auxiliary power, necessary to access to H-mode during the approach to ignition, provides for the possibility of driven burn operations at Q = 15. This enables ITER to fulfill its mission of fusion power ({approximately} 1--1.5 GW) and fluence ({approximately}1 MWa/m{sup 2}) goals if confinement, impurity levels, or operational (density, beta) limits prove to be less favorable than present projections. The power threshold for H-L transition, confinement uncertainties, and operational limits (Greenwald density limit and beta limit) are potential performance limiting issues. Improvement of the helium exhaust ({tau}*{sub He}/{tau}{sub E} {le} 5) and potential operation in reverse-shear mode significantly improve ITER performance.

  12. submitter Starting Manufacture of the ITER Central Solenoid

    CERN Document Server

    Libeyre, P; Dolgetta, N; Gaxiola, E; Jong, C; Lyraud, C; Mitchell, N; Journeaux, J Y; Vollmann, T; Evans, D; Sgobba, S; Langeslag, S; Reiersen, W; Martovetsky, N; Everitt, D; Hatfield, D; Rosenblad, P; Litherland, S; Freudenberg, K; Myatt, L; Smith, J; Brazelton, C; Abbott, R; Daubert, J; Rackers, K; Nentwich, T

    2016-01-01

    The central solenoid (CS) is a key component of the ITER magnet system to provide the magnetic flux swing required to drive induced plasma current up to 15 MA. The manufacture of its different subcomponents has now started, following completion of the design analyses and achievement of the qualification of the manufacturing procedures. A comprehensive set of analyses has been produced to demonstrate that the CS final design meets all requirements. This includes in particular structural analyses carried out with different finite-element models and addressing normal and fault conditions. Following the Final Design Review, held in November 2013, and the subsequent design modifications, the analyses were updated for consistency with the final design details and provide evidence that the Magnet Structural Design Criteria are fully met. Before starting any manufacturing activity of a CS component, a corresponding dedicated qualification program has been carried out. This includes manufacture of mockups using the re...

  13. A FAST CONVERGENT METHOD OF ITERATED REGULARIZATION

    Institute of Scientific and Technical Information of China (English)

    Huang Xiaowei; Wu Chuansheng; Wu Di

    2009-01-01

    This article presents a fast convergent method of iterated regularization based on the idea of Landweber iterated regularization, and a method for a-posteriori choice by the Morozov discrepancy principle and the optimum asymptotic convergence order of the regularized solution is obtained. Numerical test shows that the method of iterated regu-larization can quicken the convergence speed and reduce the calculation burden efficiently.

  14. Preconditioned iterations to calculate extreme eigenvalues

    Energy Technology Data Exchange (ETDEWEB)

    Brand, C.W.; Petrova, S. [Institut fuer Angewandte Mathematik, Leoben (Austria)

    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.

  15. ITER breeding blanket module design and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Toshimasa; Enoeda, Mikio; Kikuchi, Shigeto [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

    1998-11-01

    The ITER breeding blanket employs a ceramic breeder and Be neutron multiplier both in small spherical pebble form. Radial-poloidal cooling panels are arranged in the blanket box to remove the nuclear heating in these materials and to reinforce the blanket structure. At the first wall, Be armor is bonded onto the stainless steel (SS) structure to provide a low Z plasma-compatible surface and to protect the first wall/blanket structure from the direct contact with the plasma during off-normal events. Thermo-mechanical analyses and investigation of fabrication procedure have been performed for this breeding blanket. To evaluate thermo-mechanical behavior of the pebble beds including the dependency of the effective thermal conductivity on stress, analysis methods have been preliminary established by the use of special calculation option of ABAQUS code, which are briefly summarized in this report. The structural response of the breeding blanket module under internal pressure of 4 MPa (in case of in-blanket LOCA) resulted in rather high stress in the blanket side (toroidal end) wall, thus addition of a stiffening rib or increase of the wall thickness will be needed. Two-dimensional elasto-plastic analyses have been performed for the Be/SS bonded interface at the first wall taking a fabrication process based on HIP bonding and thermal cycle due to pulsed plasma operation into account. The stress-strain hysteresis during these process and operation was clarified, and a procedure to assess and/or confirm the bonding integrity was also proposed. Fabrication sequence of the breeding blanket module was preliminarily developed based on the procedure to fabricate part by part and to assemble them one by one. (author)

  16. Iterative solution of the reduced eigenvalue problem

    Energy Technology Data Exchange (ETDEWEB)

    Sauer, G. (Technischer Ueberwachungs-Verein Bayern e.V., Muenchen (Germany, F.R.))

    1991-04-01

    The Guyan method of reducing the stiffness and mass matrices of large linear structures introduces errors in the reduced mass matrix. These errors cannot be completely avoided even if the analysis coordinates are chosen optimally. However, they can be elimiated by iterating on the eigenvectors found from the Guyan reduced matrices. The necessary iteration steps follow directly from the eigenvalue problem. The resulting iteration procedures are presented and applied to two test problems showing that the iterations enable the exact eigensolutions to be extracted. All errors from the Guyan reduced matrices are removed or substantially decreased. (orig.).

  17. The motional Stark effect diagnostic for ITER using a line-shift approach.

    Science.gov (United States)

    Foley, E L; Levinton, F M; Yuh, H Y; Zakharov, L E

    2008-10-01

    The United States has been tasked with the development and implementation of a motional Stark effect (MSE) system on ITER. In the harsh ITER environment, MSE is particularly susceptible to degradation, as it depends on polarimetry, and the polarization reflection properties of surfaces are highly sensitive to thin film effects due to plasma deposition and erosion of a first mirror. Here we present the results of a comprehensive study considering a new MSE-based approach to internal plasma magnetic field measurements for ITER. The proposed method uses the line shifts in the MSE spectrum (MSE-LS) to provide a radial profile of the magnetic field magnitude. To determine the utility of MSE-LS for equilibrium reconstruction, studies were performed using the ESC-ERV code system. A near-term opportunity to test the use of MSE-LS for equilibrium reconstruction is being pursued in the implementation of MSE with laser-induced fluorescence on NSTX. Though the field values and beam energies are very different from ITER, the use of a laser allows precision spectroscopy with a similar ratio of linewidth to line spacing on NSTX as would be achievable with a passive system on ITER. Simulation results for ITER and NSTX are presented, and the relative merits of the traditional line polarization approach and the new line-shift approach are discussed.

  18. Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N. [Institution Project center ITER, Moscow (Russian Federation)

    2014-08-21

    In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ–ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.

  19. Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

    Science.gov (United States)

    Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N.

    2014-08-01

    In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ-ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.

  20. Benchmarking ICRF simulations for ITER

    Energy Technology Data Exchange (ETDEWEB)

    R. V. Budny, L. Berry, R. Bilato, P. Bonoli, M. Brambilla, R.J. Dumont, A. Fukuyama, R. Harvey, E.F. Jaeger, E. Lerche, C.K. Phillips, V. Vdovin, J. Wright, and members of the ITPA-IOS

    2010-09-28

    Abstract Benchmarking of full-wave solvers for ICRF simulations is performed using plasma profiles and equilibria obtained from integrated self-consistent modeling predictions of four ITER plasmas. One is for a high performance baseline (5.3 T, 15 MA) DT H-mode plasma. The others are for half-field, half-current plasmas of interest for the pre-activation phase with bulk plasma ion species being either hydrogen or He4. The predicted profiles are used by seven groups to predict the ICRF electromagnetic fields and heating profiles. Approximate agreement is achieved for the predicted heating power partitions for the DT and He4 cases. Profiles of the heating powers and electromagnetic fields are compared.

  1. Truncated states obtained by iteration

    CERN Document Server

    Cardoso, W B

    2007-01-01

    Quantum states of the electromagnetic field are of considerable importance, finding potential application in various areas of physics, as diverse as solid state physics, quantum communication and cosmology. In this paper we introduce the concept of truncated states obtained via iterative processes (TSI) and study its statistical features, making an analogy with dynamical systems theory (DST). As a specific example, we have studied TSI for the doubling and the logistic functions, which are standard functions in studying chaos. TSI for both the doubling and logistic functions exhibit certain similar patterns when their statistical features are compared from the point of view of DST. A general method to engineer TSI in the running-wave domain is employed, which includes the errors due to the nonidealities of detectors and photocounts.

  2. Planning as an Iterative Process

    Science.gov (United States)

    Smith, David E.

    2012-01-01

    Activity planning for missions such as the Mars Exploration Rover mission presents many technical challenges, including oversubscription, consideration of time, concurrency, resources, preferences, and uncertainty. These challenges have all been addressed by the research community to varying degrees, but significant technical hurdles still remain. In addition, the integration of these capabilities into a single planning engine remains largely unaddressed. However, I argue that there is a deeper set of issues that needs to be considered namely the integration of planning into an iterative process that begins before the goals, objectives, and preferences are fully defined. This introduces a number of technical challenges for planning, including the ability to more naturally specify and utilize constraints on the planning process, the ability to generate multiple qualitatively different plans, and the ability to provide deep explanation of plans.

  3. ITER Safety Analyses with ISAS

    Science.gov (United States)

    Gulden, W.; Nisan, S.; Porfiri, M.-T.; Toumi, I.; de Gramont, T. Boubée

    1997-06-01

    Detailed analyses of accident sequences for the International Thermonuclear Experimental Reactor (ITER), from an initiating event to the environmental release of activity, have involved in the past the use of different types of computer codes in a sequential manner. Since these codes were developed at different time scales in different countries, there is no common computing structure to enable automatic data transfer from one code to the other, and no possibility exists to model or to quantify the effect of coupled physical phenomena. To solve this problem, the Integrated Safety Analysis System of codes (ISAS) is being developed, which allows users to integrate existing computer codes in a coherent manner. This approach is based on the utilization of a command language (GIBIANE) acting as a “glue” to integrate the various codes as modules of a common environment. The present version of ISAS allows comprehensive (coupled) calculations of a chain of codes such as ATHENA (thermal-hydraulic analysis of transients and accidents), INTRA (analysis of in-vessel chemical reactions, pressure built-up, and distribution of reaction products inside the vacuum vessel and adjacent rooms), and NAUA (transport of radiological species within buildings and to the environment). In the near future, the integration of S AFALY (simultaneous analysis of plasma dynamics and thermal behavior of in-vessel components) is also foreseen. The paper briefly describes the essential features of ISAS development and the associated software architecture. It gives first results of a typical ITER accident sequence, a loss of coolant accident (LOCA) in the divertor cooling loop inside the vacuum vessel, amply demonstrating ISAS capabilities.

  4. Surface heat loads on the ITER divertor vertical targets

    Science.gov (United States)

    Gunn, J. P.; Carpentier-Chouchana, S.; Escourbiac, F.; Hirai, T.; Panayotis, S.; Pitts, R. A.; Corre, Y.; Dejarnac, R.; Firdaouss, M.; Kočan, M.; Komm, M.; Kukushkin, A.; Languille, P.; Missirlian, M.; Zhao, W.; Zhong, G.

    2017-04-01

    The heating of tungsten monoblocks at the ITER divertor vertical targets is calculated using the heat flux predicted by three-dimensional ion orbit modelling. The monoblocks are beveled to a depth of 0.5 mm in the toroidal direction to provide magnetic shadowing of the poloidal leading edges within the range of specified assembly tolerances, but this increases the magnetic field incidence angle resulting in a reduction of toroidal wetted fraction and concentration of the local heat flux to the unshadowed surfaces. This shaping solution successfully protects the leading edges from inter-ELM heat loads, but at the expense of (1) temperatures on the main loaded surface that could exceed the tungsten recrystallization temperature in the nominal partially detached regime, and (2) melting and loss of margin against critical heat flux during transient loss of detachment control. During ELMs, the risk of monoblock edge melting is found to be greater than the risk of full surface melting on the plasma-wetted zone. Full surface and edge melting will be triggered by uncontrolled ELMs in the burning plasma phase of ITER operation if current models of the likely ELM ion impact energies at the divertor targets are correct. During uncontrolled ELMs in pre-nuclear deuterium or helium plasmas at half the nominal plasma current and magnetic field, full surface melting should be avoided, but edge melting is predicted.

  5. Reduced activation martensitic steels as a structural material for ITER test blanket

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, K. E-mail: shiba@realab01.tokai.jaeri.go.jp; Enoeda, M.; Jitsukawa, S

    2004-08-01

    A Japanese ITER test blanket module (TBM) is planed to use reduced-activation martensitic steel F82H. Feasibility of F82H for ITER test blanket module is discussed in this paper. Several kinds of property data, including physical properties, magnetic properties, mechanical properties and neutron-irradiation data on F82H have been obtained, and these data are complied into a database to be used for the designing of the ITER TBM. Currently obtained data suggests F82H will not have serious problems for ITER TBM. Optimization of F82H improves the induced activity, toughness and HIP resistance. Furthermore, modified F82H is resistant to temperature instability during material production.

  6. The First Benchmarking of ITER BR Nb3Sn Strand of CNDA

    Institute of Scientific and Technical Information of China (English)

    龙风; 刘方; 武玉; 倪志鹏

    2012-01-01

    According to the International Thermonuclear Experimental Reactor (ITER) Pro- curement Arrangement (PA) of Cable-In-Conduit Conductor (CICC) unit lengths for the Toroidal Field (TF) and Poloidal Field (PF) magnet systems of ITER, at the start of process qualification, the Domestic Agency (DA) shall be required to conduct a benchmarking of the room and low tem- perature acceptance tests carried out at the Strand Suppliers and/or at its Reference Laboratories designated by the ITER Organization (IO). The first benchmarking was carried out successfully in 2009. Nineteen participants from six DAs (China, European Union, Japan, South Korea, Russia, and the United States) participated in the first benchmarking. Bronze-route (BR) Nb3Sn strand and samples prepared by the ITER reference lab (CERN) were sent out to each participant by CERN. In this paper, the test facility and test results of the first benchmarking by the Chinese DA (CNDA) are presented.

  7. Aggregation-iterative analogues and generalizations of projection-iterative methods

    Directory of Open Access Journals (Sweden)

    Shuvar B.F.

    2013-06-01

    Full Text Available Aggregation-iterative algorithms for linear operator equations are constructed and investigated. These algorithms cover methods of iterative aggregation and projection-iterative methods. In convergence conditions there is neither requirement for the corresponding operator of fixed sign no restriction to the spectral radius to be less than one.

  8. Installation of the ITER committee industry. Participants guide; Installation du Comite industrie ITER. Dossier des participants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    ITER is an international project to design and build an experimental fusion reactor based on the tokamak concept. This guide presents the ITER project and objectives and the associated organizations in France, the recommendations and actions for ITER, the industrial mobilization, the industrial committee and its members, technological sheets for the enterprises and the statistical document of the SESSI. (A.L.B.)

  9. Rater Variables Associated with ITER Ratings

    Science.gov (United States)

    Paget, Michael; Wu, Caren; McIlwrick, Joann; Woloschuk, Wayne; Wright, Bruce; McLaughlin, Kevin

    2013-01-01

    Advocates of holistic assessment consider the ITER a more authentic way to assess performance. But this assessment format is subjective and, therefore, susceptible to rater bias. Here our objective was to study the association between rater variables and ITER ratings. In this observational study our participants were clerks at the University of…

  10. Dense Iterative Contextual Pixel Classification using Kriging

    DEFF Research Database (Denmark)

    Ganz, Melanie; Loog, Marco; Brandt, Sami

    2009-01-01

    have been proposed to this end, e.g., iterative contextual pixel classification, iterated conditional modes, and other approaches related to Markov random fields. A problem of these methods, however, is their computational complexity, especially when dealing with high-resolution images in which...

  11. Iterative Brinkman penalization for remeshed vortex methods

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Koumoutsakos, Petros; Leonard, Anthony;

    2015-01-01

    We introduce an iterative Brinkman penalization method for the enforcement of the no-slip boundary condition in remeshed vortex methods. In the proposed method, the Brinkman penalization is applied iteratively only in the neighborhood of the body. This allows for using significantly larger time s...

  12. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Meo, Fernando; Korsholm, Søren Bang

    for measurements of the confined fusion alpha particles in ITER set by the ITER team. Then we outline the considerations, which enter into the selection and evaluation of CTS systems. System definition includes choice of probe frequency, geometry of probe and receiver beam patterns and probe power, but ultimately...

  13. An iterative method for spherical bounces

    CERN Document Server

    Buniy, Roman V

    2016-01-01

    We develop a new iterative method for finding approximate solutions for spherical bounces associated with the decay of the false vacuum in scalar field theories. The method works for any generic potential in any number of dimensions, contains Coleman's thin-wall approximation as its first iteration, and greatly improves its accuracy by including higher order terms.

  14. Iterative methods for weighted least-squares

    Energy Technology Data Exchange (ETDEWEB)

    Bobrovnikova, E.Y.; Vavasis, S.A. [Cornell Univ., Ithaca, NY (United States)

    1996-12-31

    A weighted least-squares problem with a very ill-conditioned weight matrix arises in many applications. Because of round-off errors, the standard conjugate gradient method for solving this system does not give the correct answer even after n iterations. In this paper we propose an iterative algorithm based on a new type of reorthogonalization that converges to the solution.

  15. New concurrent iterative methods with monotonic convergence

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Qingchuan [Michigan State Univ., East Lansing, MI (United States)

    1996-12-31

    This paper proposes the new concurrent iterative methods without using any derivatives for finding all zeros of polynomials simultaneously. The new methods are of monotonic convergence for both simple and multiple real-zeros of polynomials and are quadratically convergent. The corresponding accelerated concurrent iterative methods are obtained too. The new methods are good candidates for the application in solving symmetric eigenproblems.

  16. Experimental studies of ITER demonstration discharges

    NARCIS (Netherlands)

    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.

    2009-01-01

    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

  17. Fusion Plasma Physics and ITER - An Introduction (1/4)

    CERN Document Server

    CERN. Geneva

    2011-01-01

    In November 2006, ministers representing the world’s major fusion research communities signed the agreement formally establishing the international project ITER. Sited at Cadarache in France, the project involves China, the European Union (including Switzerland), India, Japan, the Russian Federation, South Korea and the United States. ITER is a critical step in the development of fusion energy: its role is to confirm the feasibility of exploiting magnetic confinement fusion for the production of energy for peaceful purposes by providing an integrated demonstration of the physics and technology required for a fusion power plant. The ITER tokamak is designed to study the “burning plasma” regime in deuterium-tritium (D-T) plasmas by achieving a fusion amplification factor, Q (the ratio of fusion output power to plasma heating input power), of 10 for several hundreds of seconds with a nominal fusion power output of 500MW. It is also intended to allow the study of steady-state plasma operation at Q≥5 by me...

  18. Piping structural design for the ITER thermal shield manifold

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Chang Hyun, E-mail: chnoh@nfri.re.kr [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Chung, Wooho, E-mail: whchung@nfri.re.kr [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Nam, Kwanwoo; Kang, Kyoung-O. [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Bae, Jing Do; Cha, Jong Kook [Korea Marine Equipment Research Institute, Busan 606-806 (Korea, Republic of); Kim, Kyoung-Kyu [Mecha T& S, Jinju-si 660-843 (Korea, Republic of); Hamlyn-Harris, Craig; Hicks, Robby; Her, Namil; Jun, Chang-Hoon [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2015-10-15

    Highlights: • We finalized piping design of ITER thermal shield manifold for procurement. • Support span is determined by stress and deflection limitation. • SQP, which is design optimization method, is used for the pipe design. • Benchmark analysis is performed to verify the analysis software. • Pipe design is verified by structural analyses. - Abstract: The thermal shield (TS) provides the thermal barrier in the ITER tokamak to minimize heat load transferred by thermal radiation from the hot components to the superconducting magnets operating at 4.2 K. The TS is actively cooled by 80 K pressurized helium gas which flows from the cold valve box to the cooling tubes on the TS panels via manifold piping. This paper describes the manifold piping design and analysis for the ITER thermal shield. First, maximum allowable span for the manifold support is calculated based on the simple beam theory. In order to accommodate the thermal contraction in the manifold feeder, a contraction loop is designed and applied. Sequential Quadratic Programming (SQP) method is used to determine the optimized dimensions of the contraction loop to ensure adequate flexibility of manifold pipe. Global structural behavior of the manifold is investigated when the thermal movement of the redundant (un-cooled) pipe is large.

  19. An Exploration of Advanced X-Divertors on ITER

    CERN Document Server

    Covele, Brent; Kotschenreuther, Mike; Mahajan, Swadesh

    2013-01-01

    It is found that the X-Divertor (XD) configuration [1-3] can be made with the conventional PF coil set on ITER[4], where all PF coils are outside the TF coils. Desirable configurations are possible where the PF currents are below the present maximum design limits on ITER, and where the baseline divertor cassette is used. It is possible that the XD could be 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 (SXD) [5-8] is not a feature of the XD geometry. In addition, we present an XD configuration for K-DEMO [9], 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 [10] for the Snowflake [11,12], where the required high PF currents represent a major technological challenge. The magnetic field structure in the outboard diver...

  20. Landweber iterative regularization for nearfield acoustic holography

    Institute of Scientific and Technical Information of China (English)

    BI Chuanxing; CHEN Xinzhao; ZHOU Rong; CHEN Jian

    2006-01-01

    On the basis of the distributed source boundary point method (DSBPM)-based nearfield acoustic holography (NAH), Landweber iterative regularization method is proposed to stabilize the NAH reconstruction process, control the influence of measurement errors on the reconstructed results and ensure the validity of the reconstructed results. And a new method, the auxiliary surface method, is proposed to determine the optimal iterative number for optimizing the regularization effect. Here, the optimal number is determined by minimizing the relative error between the calculated pressure on the auxiliary surface corresponding to each iterative number and the measured pressure. An experiment on a speaker is investigated to demonstrate the high sensitivity of the reconstructed results to measurement errors and to validate the chosen method of the optimal iterative number and the Landweber iterative regularization method for controlling the influence of measurement errors on the reconstructed results.

  1. Turbo iterative equalization for HSDPA systems

    Institute of Scientific and Technical Information of China (English)

    WU QiHui; ZHAO ChunMing; WANG JinLong

    2007-01-01

    In this paper, a turbo iterative receiver structure with chip equalization is proposed for the 3G high-speed downlink packet access (HSDPA) systems. The receiver equalizes the channel prior to the dispreading and then performs two successive soft-output decisions, achieved by a soft-input soft-output (SISO) multi-code detector and a SISO turbo decoder through an iterative process. At each iteration, extrinsic information is extracted from detection and decoding stages and is then used as a priori information in the next iteration, just as in turbo decoding. Computer simulations show that the turbo iterative receiver structure with chip equalization offers significant performance gain over the traditional receiver structure.

  2. Techniques in Iterative Proton CT Image Reconstruction

    CERN Document Server

    Penfold, Scott

    2015-01-01

    This is a review paper on some of the physics, modeling, and iterative algorithms in proton computed tomography (pCT) image reconstruction. The primary challenge in pCT image reconstruction lies in the degraded spatial resolution resulting from multiple Coulomb scattering within the imaged object. Analytical models such as the most likely path (MLP) have been proposed to predict the scattered trajectory from measurements of individual proton location and direction before and after the object. Iterative algorithms provide a flexible tool with which to incorporate these models into image reconstruction. The modeling leads to a large and sparse linear system of equations that can efficiently be solved by projection methods-based iterative algorithms. Such algorithms perform projections of the iterates onto the hyperlanes that are represented by the linear equations of the system. They perform these projections in possibly various algorithmic structures, such as block-iterative projections (BIP), string-averaging...

  3. Recent improvements to the ITER neutral beam system design

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, L.R., E-mail: lgrisham@pppl.gov [Princeton University, Plasma Physics Laboratory, P.O. Box 451, Princeton, NJ 08543 (United States); Agostinetti, P. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Barrera, G. [EURATOM-CIEMAT Association, Avda. Complutense 40, 28040 Madrid (Spain); Blatchford, P. [Culham Center for Fusion Energy, Abingdon, Oxon. OX14 3DB (United Kingdom); Boilson, D.; Chareyre, J. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Chitarin, G. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Esch, H.P.L. de [CEA-Cadarache, IRFM, F-13108 Saint-Paul-lez-Durance (France); De Lorenzi, A. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Franzen, P.; Fantz, U. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Gagliardi, M. [Culham Center for Fusion Energy, Abingdon, Oxon. OX14 3DB (United Kingdom); Hemsworth, R.S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Kashiwagi, M. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); King, D. [Culham Center for Fusion Energy, Abingdon, Oxon. OX14 3DB (United Kingdom); Krylov, A. [Russian Research Centre, Kurchatov Institute, Moscow (Russian Federation); Kuriyama, M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Marconato, N.; Marcuzzi, D. [Consorzio RFX, Euratom-ENEA Association, C.so Stati Uniti 4, I-35127 Padova (Italy); Roccella, M. [L.T. Calcoli SaS, Via C. Baslini 13, 23807 Merate (Italy); and others

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Improvements to ITER accelerator voltage holding. Black-Right-Pointing-Pointer Improvements to ITER negative ion source design. Black-Right-Pointing-Pointer Improvements to ITER megavolt bushing. Black-Right-Pointing-Pointer Improvements to beamline components. Black-Right-Pointing-Pointer Accelerator design improvements. - Abstract: The ITER [1] fusion device is expected to demonstrate the feasibility of magnetically confined deuterium-tritium plasma as an energy source which might one day lead to practical power plants. Injection of energetic beams of neutral atoms (up to 1 MeV D{sup 0} or up to 870 keV H{sup 0}) will be one of the primary methods used for heating the plasma, and for driving toroidal electrical current within it, the latter being essential in producing the required magnetic confinement field configuration. The design calls for each beamline to inject up to 16.5 MW of power through the duct into the tokamak, with an initial complement of two beamlines injecting parallel to the direction of the current arising from the tokamak transformer effect, and with the possibility of eventually adding a third beamline, also in the co-current direction. The general design of the beamlines has taken shape over the past 17 years [2], and is now predicated upon an RF-driven negative ion source based upon the line of sources developed by the Institute for Plasma Physics (IPP) at Garching during recent decades [3-5], and a multiple-aperture multiple-grid electrostatic accelerator derived from negative ion accelerators developed by the Japan Atomic Energy Agency (JAEA) across a similar span of time [6-8]. During the past years, the basic concept of the beam system has been further refined and developed, and assessment of suitable fabrication techniques has begun. While many design details which will be important to the installation and implementation of the ITER beams have been worked out during this time, this paper focuses

  4. IVVS actuating system compatibility test to ITER gamma radiation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Paolo, E-mail: paolo.rossi@enea.it [Associazione EURATOM-ENEA sulla Fusione, 45 Via Enrico Fermi, 00044 Frascati, Rome (Italy); Collibus, M. Ferri de; Florean, M.; Monti, C.; Mugnaini, G.; Neri, C.; Pillon, M.; Pollastrone, F. [Associazione EURATOM-ENEA sulla Fusione, 45 Via Enrico Fermi, 00044 Frascati, Rome (Italy); Baccaro, S.; Piegari, A. [ENEA CR Casaccia, 301 Via Anguillarese, 00123 Santa Maria di Galeria, Rome (Italy); Damiani, C.; Dubus, G. [Fusion For Energy c/Josep Pla, n° 2 Torres Diagonal Litoral, 08019 Barcelona (Spain)

    2013-10-15

    Highlights: • ENEA developed and tested a prototype of a laser In Vessel Viewing and ranging System (IVVS) for ITER. • One piezo-motor prototype has been tested on the ENEA Calliope gamma irradiation facility to verify its compatibility to ITER gamma radiation conditions. • After a total dose of more than 4 MGy the piezo-motor maintained almost the same working parameters monitored before test without any evident and significant degradation of functionality. • After the full gamma irradiation test, the same piezo-motor assembly will be tested with 14 MeV neutrons irradiation using ENEA FNG facility. -- Abstract: The In Vessel Viewing System (IVVS) is a fundamental remote handling equipment, which will be used to make a survey of the status of the blanket first wall and divertor plasma facing components. A design and testing activity is ongoing, in the framework of a Fusion for Energy (F4E) grant agreement, to make the IVVS probe design compatible with ITER operating conditions and in particular, but not only, with attention to neutrons and gammas fluxes and both space constraints and interfaces. The paper describes the testing activity performed on the customized piezoelectric motors and the main components of the actuating system of the IVVS probe with reference to ITER gamma radiation conditions. In particular the test is performed on the piezoelectric motor, optical encoder and small scale optical samples .The test is carried out on the ENEA Calliope gamma irradiation facility at ITER relevant gamma fields at rate of about 2.5 kGy/h and doses of 4 MGy. The paper reports in detail the setup arrangement of the test campaign in order to verify significant working capability of the IVVS actuating components and the results are shown in terms of functional performances and parameters. The overall test campaign on IVVS actuating system will be completed on other ENEA testing facilities in order to verify compatibility to Magnetic field, neutrons and thermal

  5. TGLF Recalibration for ITER Standard Case Parameters FY2015: Theory and Simulation Performance Target Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J. [General Atomics, San Diego, CA (United States)

    2015-12-01

    This work was motivated by the observation, as early as 2008, that GYRO simulations of some ITER operating scenarios exhibited nonlinear zonal-flow generation large enough to effectively quench turbulence inside r /a ~ 0.5. This observation of flow-dominated, low-transport states persisted even as more accurate and comprehensive predictions of ITER profiles were made using the state-of-the-art TGLF transport model. This core stabilization is in stark contrast to GYRO-TGLF comparisons for modern-day tokamaks, for which GYRO and TGLF are typically in very close agreement. So, we began to suspect that TGLF needed to be generalized to include the effect of zonal-flow stabilization in order to be more accurate for the conditions of reactor simulations. While the precise cause of the GYRO-TGLF discrepancy for ITER parameters was not known, it was speculated that closeness to threshold in the absence of driven rotation, as well as electromagnetic stabilization, created conditions more sensitive the self-generated zonal-flow stabilization than in modern tokamaks. Need for nonlinear zonal-flow stabilization: To explore the inclusion of a zonal-flow stabilization mechanism in TGLF, we started with a nominal ITER profile predicted by TGLF, and then performed linear and nonlinear GYRO simulations to characterize the behavior at and slightly above the nominal temperature gradients for finite levels of energy transport. Then, we ran TGLF on these cases to see where the discrepancies were largest. The predicted ITER profiles were indeed near to the TGLF threshold over most of the plasma core in the hybrid discharge studied (weak magnetic shear, q > 1). Scanning temperature gradients above the TGLF power balance values also showed that TGLF overpredicted the electron energy transport in the low-collisionality ITER plasma. At first (in Q3), a model of only the zonal-flow stabilization (Dimits shift) was attempted. Although we were able to construct an ad hoc model of the zonal

  6. TGLF Recalibration for ITER Standard Case Parameters FY2015: Theory and Simulation Performance Target Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J. [General Atomics, San Diego, CA (United States)

    2015-12-01

    This work was motivated by the observation, as early as 2008, that GYRO simulations of some ITER operating scenarios exhibited nonlinear zonal-flow generation large enough to effectively quench turbulence inside r /a ~ 0.5. This observation of flow-dominated, low-transport states persisted even as more accurate and comprehensive predictions of ITER profiles were made using the state-of-the-art TGLF transport model. This core stabilization is in stark contrast to GYRO-TGLF comparisons for modern-day tokamaks, for which GYRO and TGLF are typically in very close agreement. So, we began to suspect that TGLF needed to be generalized to include the effect of zonal-flow stabilization in order to be more accurate for the conditions of reactor simulations. While the precise cause of the GYRO-TGLF discrepancy for ITER parameters was not known, it was speculated that closeness to threshold in the absence of driven rotation, as well as electromagnetic stabilization, created conditions more sensitive the self-generated zonal-flow stabilization than in modern tokamaks. Need for nonlinear zonal-flow stabilization: To explore the inclusion of a zonal-flow stabilization mechanism in TGLF, we started with a nominal ITER profile predicted by TGLF, and then performed linear and nonlinear GYRO simulations to characterize the behavior at and slightly above the nominal temperature gradients for finite levels of energy transport. Then, we ran TGLF on these cases to see where the discrepancies were largest. The predicted ITER profiles were indeed near to the TGLF threshold over most of the plasma core in the hybrid discharge studied (weak magnetic shear, q > 1). Scanning temperature gradients above the TGLF power balance values also showed that TGLF overpredicted the electron energy transport in the low-collisionality ITER plasma. At first (in Q3), a model of only the zonal-flow stabilization (Dimits shift) was attempted. Although we were able to construct an ad hoc model of the zonal

  7. Effects of Repetitive Transcranial Magnetic Stimulation in Performing Eye-Hand Integration Tasks: Four Preliminary Studies with Children Showing Low-Functioning Autism

    Science.gov (United States)

    Panerai, Simonetta; Tasca, Domenica; Lanuzza, Bartolo; Trubia, Grazia; Ferri, Raffaele; Musso, Sabrina; Alagona, Giovanna; Di Guardo, Giuseppe; Barone, Concetta; Gaglione, Maria P.; Elia, Maurizio

    2014-01-01

    This report, based on four studies with children with low-functioning autism, aimed at evaluating the effects of repetitive transcranial magnetic stimulation delivered on the left and right premotor cortices on eye-hand integration tasks; defining the long-lasting effects of high-frequency repetitive transcranial magnetic stimulation; and…

  8. Iterants, Fermions and Majorana Operators

    Science.gov (United States)

    Kauffman, Louis H.

    Beginning with an elementary, oscillatory discrete dynamical system associated with the square root of minus one, we study both the foundations of mathematics and physics. Position and momentum do not commute in our discrete physics. Their commutator is related to the diffusion constant for a Brownian process and to the Heisenberg commutator in quantum mechanics. We take John Wheeler's idea of It from Bit as an essential clue and we rework the structure of that bit to a logical particle that is its own anti-particle, a logical Marjorana particle. This is our key example of the amphibian nature of mathematics and the external world. We show how the dynamical system for the square root of minus one is essentially the dynamics of a distinction whose self-reference leads to both the fusion algebra and the operator algebra for the Majorana Fermion. In the course of this, we develop an iterant algebra that supports all of matrix algebra and we end the essay with a discussion of the Dirac equation based on these principles.

  9. On the interplay between inner and outer iterations for a class of iterative methods

    Energy Technology Data Exchange (ETDEWEB)

    Giladi, E. [Stanford Univ., CA (United States)

    1994-12-31

    Iterative algorithms for solving linear systems of equations often involve the solution of a subproblem at each step. This subproblem is usually another linear system of equations. For example, a preconditioned iteration involves the solution of a preconditioner at each step. In this paper, the author considers algorithms for which the subproblem is also solved iteratively. The subproblem is then said to be solved by {open_quotes}inner iterations{close_quotes} while the term {open_quotes}outer iteration{close_quotes} refers to a step of the basic algorithm. The cost of performing an outer iteration is dominated by the solution of the subproblem, and can be measured by the number of inner iterations. A good measure of the total amount of work needed to solve the original problem to some accuracy c is then, the total number of inner iterations. To lower the amount of work, one can consider solving the subproblems {open_quotes}inexactly{close_quotes} i.e. not to full accuracy. Although this diminishes the cost of solving each subproblem, it usually slows down the convergence of the outer iteration. It is therefore interesting to study the effect of solving each subproblem inexactly on the total amount of work. Specifically, the author considers strategies in which the accuracy to which the inner problem is solved, changes from one outer iteration to the other. The author seeks the `optimal strategy`, that is, the one that yields the lowest possible cost. Here, the author develops a methodology to find the optimal strategy, from the set of slowly varying strategies, for some iterative algorithms. This methodology is applied to the Chebychev iteration and it is shown that for Chebychev iteration, a strategy in which the inner-tolerance remains constant is optimal. The author also estimates this optimal constant. Then generalizations to other iterative procedures are discussed.

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

    NARCIS (Netherlands)

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

    2013-01-01

    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 conduc

  11. Impact and mitigation of disruptions with the ITER-like wall in JET

    NARCIS (Netherlands)

    Lehnen, M.; Arnoux, G.; Brezinsek, S.; Flanagan, J.; Gerasimov, S. N.; Hartmann, N.; Hender, T. C.; Huber, A.; Jachmich, S.; Kiptily, V.; Kruezi, U.; Matthews, G. F.; Morris, J.; Plyusnin, V. V.; Reux, C.; Riccardo, V.; Sieglin, B.; de Vries, P. C.; JET-EFDA Contributors,

    2013-01-01

    Disruptions are a critical issue for ITER because of the high thermal and magnetic energies that are released on short timescales, which results in extreme forces and heat loads. The choice of material of the plasma-facing components (PFCs) can have significant impact on the loads that arise during

  12. ITER test blanket module error field simulation experiments at DIII-D

    NARCIS (Netherlands)

    Schaffer, M. J.; Snipes, J. A.; Gohil, P.; P. de Vries,; Evans, T. E.; Fenstermacher, M.E.; Gao, X.; Garofalo, A. M.; Gates, D. A.; Greenfield, C.M.; Heidbrink, W. W.; Kramer, G. J.; La Haye, R. J.; Liu, S.; Loarte, A.; Nave, M. F. F.; Osborne, T. H.; Oyama, N.; Park, J. K.; Ramasubramanian, N.; Reimerdes, H.; Saibene, G.; Salmi, A.; Shinohara, K.; Spong, D. A.; Solomon, W. M.; Tala, T.; Zhu, Y. B.; Boedo, J. A.; Chuyanov, V.; Doyle, E. J.; Jakubowski, M.; Jhang, H.; Nazikian, R. M.; Pustovitov, V. D.; Schmitz, O.; Srinivasan, R.; Taylor, T. S.; Wade, M. R.; You, K. I.; Zeng, L.

    2011-01-01

    Experiments at DIII-D investigated the effects of magnetic error fields similar to those expected from proposed ITER test blanket modules (TBMs) containing ferromagnetic material. Studied were effects on: plasma rotation and locking, confinement, L-H transition, the H-mode pedestal, edge localized m

  13. Newton—Like Iteration Method for Solving Algebraic Equations

    Institute of Scientific and Technical Information of China (English)

    JihuanHE

    1998-01-01

    In this paper,a Newton-like iteration method is proposed to solve an approximate solution of an algebraic equation.The iteration formula obtained by homotopy perturbation method contains the well-known Newton iteration formulain logic.

  14. A Non-iterative Algorithm to Estimate Water Molecule Diffusion Coefficient in Magnetic Resonance Imaging%一种用于估算磁共振成像中水分子扩散系数的非迭代算法

    Institute of Scientific and Technical Information of China (English)

    高嵩; 王飞

    2012-01-01

    目的 提出一种更加可靠和高效的算法,用于计算磁共振扩散加权成像(DWI)中人体内水分子的扩散系数.方法 根据扩散加权成像中磁共振信号的双指数衰减规律,我们提出了双线性拟合算法以替代现在广泛使用的Levenberg-Marquardt迭代算法.使用两次线性拟合分别计算快慢扩散系数,整个计算过程中不必估算初始值.结果 双线性拟合算法计算所用时间远少于Levenberg-Marquardt算法,计算结果合理.而Levenberg-Marquardt算法的结果中有大量额外解.结论 与Levenberg-Marquardt算法相比,双线性拟合算法在分析磁共振扩散加权成像数据方面不仅算法可靠而且计算效率高.%Objective To propose a more reliable and time-efficient algorithm to estimate the diffusion coefficients of water molecular in magnetic resonance diffusion weighted imaging ( DWI ) experiments in vivo.Methods According to the novel feature from the bi-exponential attenuation of diffusion weighted magnetic resonance signal,the authors proposed the algorithm of twice-linear-fitting instead of the commonly used iterative Levenberg-Marquardt method.This algorithm consisted of two liner fitting steps to estimate the fast and slow diffusion coefficients respectively.It was unnecessary to estimate the initial value in the whole fitting process.Results The time consumption of the twice-linear-fitting algorithm was much less than that of the LevenbergMarquardt method.All results from the examples were reasonable.However,there were extraneous solutions in the results of Levenberg-Marquardt algorithm.Conclusion Compared with the Levenberg-Marquardt method,the twice-linear-fitting algorithm is a reliable and more time-efficient approach to estimate the diffusion coefficient in magnetic resonance diffusion weighted imaging.

  15. Nuclear technology aspects of ITER vessel-mounted diagnostics

    Science.gov (United States)

    Vayakis, George; Bertalot, Luciano; Encheva, Anna; Walker, Chris; Brichard, Benoît; Cheon, M. S.; Chitarin, G.; Hodgson, Eric; Ingesson, Christian; Ishikawa, M.; Kondoh, T.; Meister, Hans; Moreau, Philippe; Peruzzo, Simone; Pak, S.; Pérez-Pichel, Germán; Reichle, Roger; Testa, Duccio; Toussaint, Matthieu; Vermeeren, Ludo; Vershkov, Vladimir

    2011-10-01

    ITER has diagnostics with machine protection, basic and advanced control, and physics roles. Several are distributed on the inner and outer periphery of the vacuum vessel. They have reduced maintainability compared to diagnostics in ports. They also endure some of the highest nuclear and EM loads of any diagnostic for the longest time. They include: Inductive sensors for time-integrated and raw inductive measurements; Steady-state magnetic sensors to correct drifts of the inductive sensors; Bolometer cameras to provide electromagnetic radiation tomography; Microfission chambers and neutron activation stations to provide fusion power and fluence; MM-wave reflectometry to measure the plasma density profile and the plasma-wall distance and; Wiring to service magnetics, bolometry, and in-vessel instrumentation. This paper summarises the key technological issues these diagnostics arising from the nuclear environment, recent progress and outstanding R&D for each system.

  16. DESIGN OF THE ITER IN-VESSEL COILS

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  17. Progress of the ECRH Upper Launcher design for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, D., E-mail: dirk.strauss@kit.edu [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Aiello, G. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Bruschi, A. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Chavan, R. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Farina, D.; Figini, L. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Gagliardi, M.; Garcia, V. [Fusion for Energy, Barcelona (Spain); Goodman, T.P. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Grossetti, G. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Heemskerk, C. [Heemskerk Innovative Technology, Merelhof 2, 2172 HZ Sassenheim (Netherlands); Henderson, M.A. [ITER Organization, 13108 Saint-Paul-lez-Durance (France); Kasparek, W. [Institut für Plasmaforschung, IPF, D-70569 Stuttgart (Germany); Krause, A.; Landis, J.-D. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Meier, A. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Moro, A.; Platania, P. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Plaum, B. [Institut für Plasmaforschung, IPF, D-70569 Stuttgart (Germany); Poli, E. [Max-Planck-IPP, Euratom Association, D-85748 Garching (Germany); and others

    2014-10-15

    The design of the ITER ECRH system provides 20 MW millimeter wave power for central plasma heating and MHD stabilization. The system consists of an array of 24 gyrotrons with power supplies coupled to a set of transmission lines guiding the beams to the four upper and the equatorial launcher. The front steering upper launcher design described herein has passed successfully the preliminary design review, and it is presently in the final design stage. The launcher consists of a millimeter wave system and steering mechanism with neutron shielding integrated into an upper port plug with the plasma facing blanket shield module (in-vessel) and a set of ex-vessel waveguides connecting the launcher to the transmission lines. Part of the transmission lines are the ultra-low loss CVD torus diamond windows and a shutter valve, a miter bend section and the feedthroughs integrated in the plug closure plate. These components are connected by corrugated waveguides and form together the first confinement system (FCS). In-vessel, the millimeter-wave system includes a quasi-optical beam propagation system including four mirror sets and a front steering mirror. The millimeter wave system is integrated into a specifically optimized upper port plug providing structural stability to withstand plasma disruption forces and the high heat load from the plasma side with a dedicated blanket shield module. A recent update in the ITER interface definition has resulted in the recession of the upper port plug first wall panels, which is now integrated into the design. Apart from the millimeter wave system the upper port plug houses also a set of shield blocks which provide neutron shielding. An overview of the actual ITER ECRH Upper Launcher is given together with some highlights of the design.

  18. Modeling Results for the ITER Cryogenic Fore Pump

    Science.gov (United States)

    Zhang, Dongsheng

    The work presented here is the analysis and modeling of the ITER-Cryogenic Fore Pump (CFP), also called Cryogenic Viscous Compressor (CVC). Unlike common cryopumps that are usually used to create and maintain vacuum, the cryogenic fore pump is designed for ITER to collect and compress hydrogen isotopes during the regeneration process of the torus cryopumps. Different from common cryopumps, the ITER-CFP works in the viscous flow regime. As a result, both adsorption boundary conditions and transport phenomena contribute unique features to the pump performance. In this report, the physical mechanisms of cryopumping are studied, especially the diffusion-adsorption process and these are coupled with the standard equations of species, momentum and energy balance, as well as the equation of state. Numerical models are developed, which include highly coupled non-linear conservation equations of species, momentum, and energy and equation of state. Thermal and kinetic properties are treated as functions of temperature, pressure, and composition of the gas fluid mixture. To solve such a set of equations, a novel numerical technique, identified as the Group-Member numerical technique is proposed. This document presents three numerical models: a transient model, a steady state model, and a hemisphere (or molecular flow) model. The first two models are developed based on analysis of the raw experimental data while the third model is developed as a preliminary study. The modeling results are compared with available experiment data for verification. The models can be used for cryopump design, and can also benefit problems, such as loss of vacuum in a cryomodule or cryogenic desublimation. The scientific and engineering investigation being done here builds connections between Mechanical Engineering and other disciplines, such as Chemical Engineering, Physics, and Chemistry.

  19. Halpern Iteration in CAT(κ) Spaces

    Institute of Scientific and Technical Information of China (English)

    Bo(z)ena PI(A)TEK

    2011-01-01

    In this paper we show that an iterative sequence generated by the Halpern algorithm converges to a fixed point in the case of complete CAT(κ) spaces. Similar results for Hadamard manifolds were obtained in[Li,C.,López, G., Martín-Márquez, V.:Iterative algorithms for nonexpansive mappings on Hadamard manifolds. Taiwanese J. Math., 14, 541-559 (2010)], but we study a much more general case. Moreover, we discuss the Halpern iteration procedure for set-valued mappings.

  20. Iterative restoration algorithms for nonlinear constraint computing

    Science.gov (United States)

    Szu, Harold

    A general iterative-restoration principle is introduced to facilitate the implementation of nonlinear optical processors. The von Neumann convergence theorem is generalized to include nonorthogonal subspaces which can be reduced to a special orthogonal projection operator by applying an orthogonality condition. This principle is shown to permit derivation of the Jacobi algorithm, the recursive principle, the van Cittert (1931) deconvolution method, the iteration schemes of Gerchberg (1974) and Papoulis (1975), and iteration schemes using two Fourier conjugate domains (e.g., Fienup, 1981). Applications to restoring the image of a double star and division by hard and soft zeros are discussed, and sample results are presented graphically.

  1. ITER fast ion collective Thomson scattering, conceptual design of 60 GHz system

    Energy Technology Data Exchange (ETDEWEB)

    Meo, F.; Bindslev, H.; Korsholm, S.B.

    2007-08-15

    The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma. The fast ion CTS diagnostic consists of two separate systems. Each system has its own RF launcher and separate set of detectors. The first system measures the perpendicular component of the fast ion velocity distribution. It consists of radially directed RF launcher and receiver, both located in the equatorial port on the low field side (LFS). This system will be referred to by the acronym LFS-BS system referring to the location of the receiver and the fact that it measures backscattered radiation. The second part of the CTS diagnostic measures the parallel component of the fast ion distribution. It consists of an RF launcher located in the mid-plane port on the LFS and a receiver mounted on the inner vacuum vessel wall that views the plasma from between two blanket modules. This system will be referred to as HFS-FS referring to the location of the receivers and that they measure forward scattered radiation. The design of both LFS-BS and HFS-FS receivers is aimed at measuring at different spatial locations simultaneously with no moveable components near the plasma. This report is a preliminary study of the hardware design and engineering constraints for this frequency range. Section 2 conceptually describes the two systems and their main components. Section 3 clarifies the impact of design parameters such as beam widths and scattering angle on the CTS measurements. With this in hand, the ITER measurement requirements are translated into constraints on the CTS system designs. An important result in this section is that systems can be designed inside these constraints. Section 4 outlines the technical feasibility and describes in more detail the design and the engineering

  2. Frozen Landweber Iteration for Nonlinear Ill-Posed Problems

    Institute of Scientific and Technical Information of China (English)

    J.Xu; B.Han; L.Li

    2007-01-01

    In this paper we propose a modification of the Landweber iteration termed frozen Landweber iteration for nonlinear ill-posed problems.A convergence analysis for this iteration is presented.The numerical performance of this frozen Landweber iteration for a nonlinear Hammerstein integral equation is compared with that of the Landweber iteration.We obtain a shorter running time of the frozen Landweber iteration based on the same convergence accuracy.

  3. An Iterative Algorithm to Build Chinese Language Models

    CERN Document Server

    Luo, X; Luo, Xiaoqiang; Roukos, Salim

    1996-01-01

    We present an iterative procedure to build a Chinese language model (LM). We segment Chinese text into words based on a word-based Chinese language model. However, the construction of a Chinese LM itself requires word boundaries. To get out of the chicken-and-egg problem, we propose an iterative procedure that alternates two operations: segmenting text into words and building an LM. Starting with an initial segmented corpus and an LM based upon it, we use a Viterbi-liek algorithm to segment another set of data. Then, we build an LM based on the second set and use the resulting LM to segment again the first corpus. The alternating procedure provides a self-organized way for the segmenter to detect automatically unseen words and correct segmentation errors. Our preliminary experiment shows that the alternating procedure not only improves the accuracy of our segmentation, but discovers unseen words surprisingly well. The resulting word-based LM has a perplexity of 188 for a general Chinese corpus.

  4. Clinical applications of iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Eberl, S. [Royal Prince Alfred Hospital, Camperdown, NSW (Australia). Department of PET and Nuclear Medicine

    1998-03-01

    Expectation maximisation (EM) reconstruction largely eliminates the hot and cold streaking artifacts characteristic of filtered-back projection (FBP) reconstruction around localised hot areas, such as the bladder. It also substantially reduces the problem of decreased inferior wall counts in MIBI myocardial perfusion studies due to ``streaking`` from high liver uptake. Non-uniform attenuation and scatter correction, resolution recovery, anatomical information, e.g. from MRI or CT tracer kinetic modelling, can all be built into the EM reconstruction imaging model. The properties of ordered subset EM (OSEM) have also been used to correct for known patient motion as part of the reconstruction process. These uses of EM are elaborated more fully in some of the other abstracts of this meeting. Currently we use OSEM routinely for: (i) studies where streaking is a problem, including all MIBI myocardial perfusion studies, to avoid hot liver inferior wall artifact, (ii) all whole body FDG PET, all lung V/Q SPECT (which have a short acquisition time) and all gated {sup 201}TI myocardial perfusion studies due to improved noise characteristics of OSEM in these studies; (iii) studies with measured, non-uniform attenuation correction. With the accelerated OSEM algorithm, iterative reconstruction is practical for routine clinical applications and we have found OSEM to provide clearly superior reconstructions for the areas listed above and are investigating its application to other studies. In clinical use, we have not found OSEM to introduce artifacts which would not also occur with FBP, e.g. uncorrected patient motion will cause artifacts with both OSEM and FBP.

  5. Experiments on water detritiation and cryogenic distillation at TLK; Impact on ITER fuel cycle subsystems interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, I.; Cristescu, I. R.; Doerr, L.; Hellriegel, G.; Michling, R. [Forschungszentrum Karlsruhe, Inst. for Technical Physics, Tritium Laboratory Karlsruhe, P.O. Box 3640, D- 76021 Karlsruhe (Germany); Murdoch, D. [EFDA CSU, MPI fuer Plasmaphysik, Garching (Germany); Schaefer, P.; Welte, S.; Wurster, W. [Forschungszentrum Karlsruhe, Inst. for Technical Physics, Tritium Laboratory Karlsruhe, P.O. Box 3640, D- 76021 Karlsruhe (Germany)

    2008-07-15

    The ITER Isotope Separation System (ISS) and Water Detritiation System (WDS) should be integrated in order to reduce potential chronic tritium emissions from the ISS. This is achieved by routing the top (protium) product from the ISS to a feed point near the bottom end of the WDS Liquid Phase Catalytic Exchange (LPCE) column. This provides an additional barrier against ISS emissions and should mitigate the memory effects due to process parameter fluctuations in the ISS. To support the research activities needed to characterize the performances of various components for WDS and ISS processes under various working conditions and configurations as needed for ITER design, an experimental facility called TRENTA representative of the ITER WDS and ISS protium separation column, has been commissioned and is in operation at TLK The experimental program on TRENTA facility is conducted to provide the necessary design data related to the relevant ITER operating modes. The operation availability and performances of ISS-WDS have impact on ITER fuel cycle subsystems with consequences on the design integration. The preliminary experimental data on TRENTA facility are presented. (authors)

  6. On the safety of ITER accelerators.

    Science.gov (United States)

    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.

  7. Applications of the ergodic iteration theorem

    OpenAIRE

    Zapletal, J.

    2010-01-01

    I prove several natural preservation theorems for the countable support iteration. This solves a question of Roslanowski regarding the preservation of localization properties and greatly simplifies the proofs in the area.

  8. Archimedes' Pi--An Introduction to Iteration.

    Science.gov (United States)

    Lotspeich, Richard

    1988-01-01

    One method (attributed to Archimedes) of approximating pi offers a simple yet interesting introduction to one of the basic ideas of numerical analysis, an iteration sequence. The method is described and elaborated. (PK)

  9. Stability of Jungck-type iterative procedures

    Directory of Open Access Journals (Sweden)

    S. L. Singh

    2005-01-01

    Full Text Available We introduce and discuss the stability of Jungck and Jungck-Mann iterative procedures for a pair of Jungck-Osilike-type maps on an arbitrary set with values in a metric or linear metric space.

  10. Anderson Acceleration for Fixed-Point Iterations

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Homer F. [Worcester Polytechnic Institute, MA (United States)

    2015-08-31

    The purpose of this grant was to support research on acceleration methods for fixed-point iterations, with applications to computational frameworks and simulation problems that are of interest to DOE.

  11. Status and verification strategy for ITER neutronics

    Energy Technology Data Exchange (ETDEWEB)

    Loughlin, Michael, E-mail: michael.loughlin@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Angelone, Maurizio [Associazione EURATOM-ENEA Sulla Fusione, Via E. Fermi 45, I-00044 Frascati, Roma (Italy); Batistoni, Paola [Associazione EURATOM-ENEA Sulla Fusione, Via E. Fermi 45, I-00044 Frascati, Roma (Italy); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Bertalot, Luciano [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Eskhult, Jonas [Studsvik Nuclear AB, SE-611 Nyköping (Sweden); Konno, Chikara [Japan Atomic Energy Agency Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Pampin, Raul [F4E Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, Barcelona 08019 (Spain); Polevoi, Alexei; Polunovskiy, Eduard [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2014-10-15

    The paper summarizes the current status of neutronics at ITER and a first set of proposals for experimental programmes to be conducted in the early operational life-time of ITER are described for the more crucial areas. These include a TF coils heating benchmark, a streaming benchmark and streaming measurements by activation on ITER itself. Also on ITER the measurement of activated water from triton burn-up should be planned and performed. This will require the measurement of triton burn-up in DD phase. Measurements of neutron flux in the tokamak building during DD operations should also be carried out. The use of JET for verification of shut down dose rate estimates is desirable. Other facilities to examine the production and behaviour of activated corrosion products and the shielding properties of concretes to high energy (6 MeV) gamma-rays are recommended.

  12. Accelerating Iterative Big Data Computing Through MPI

    Institute of Scientific and Technical Information of China (English)

    梁帆; 鲁小亿

    2015-01-01

    Current popular systems, Hadoop and Spark, cannot achieve satisfied performance because of the inefficient overlapping of computation and communication when running iterative big data applications. The pipeline of computing, data movement, and data management plays a key role for current distributed data computing systems. In this paper, we first analyze the overhead of shuffle operation in Hadoop and Spark when running PageRank workload, and then propose an event-driven pipeline and in-memory shuffle design with better overlapping of computation and communication as DataMPI-Iteration, an MPI-based library, for iterative big data computing. Our performance evaluation shows DataMPI-Iteration can achieve 9X∼21X speedup over Apache Hadoop, and 2X∼3X speedup over Apache Spark for PageRank and K-means.

  13. Overview and status of ITER internal components

    Energy Technology Data Exchange (ETDEWEB)

    Merola, Mario, E-mail: mario.merola@iter.org; Escourbiac, Frederic; Raffray, René; Chappuis, Philippe; Hirai, Takeshi; Martin, Alex

    2014-10-15

    Highlights: • Manufacturing technologies for the ITER internal components have been developed. • The Blanket System successfully went through its Final Design Review in April 2013. • The decision to start operation with a Divertor with a full-W armour has been taken. - Abstract: The internal components of ITER are one of the most design and technically challenging components of the ITER machine, and include the Blanket System and the Divertor. The Blanket System successfully went through its Final Design Review in April 2013 and now it is entering into the procurement phase. The design and qualification of the Divertor with a full-tungsten armour was successfully completed and this enabled the decision in November 2013 to start operation with this material option. This paper summarizes the engineering design, the R and D, the technology qualification and procurement status of the Blanket System and of the Divertor of the ITER machine.

  14. Experiences with iterated traffic microsimulations in Dallas

    CERN Document Server

    Nagel, K

    1997-01-01

    This paper reports experiences with iterated traffic microsimulations in the context of a Dallas study. ``Iterated microsimulations'' here means that the information generated by a microsimulation is fed back into the route planner so that the simulated individuals can adjust their routes to circumvent congestion. This paper gives an overview over what has been done in the Dallas context to better understand the relaxation process, and how to judge the robustness of the results.

  15. A steerable ECRF launcher for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Grunloh, H.; Prater, R.; Doane, J.L.; Moeller, C.P. [General Atomics, San Diego (United States); Makowski, M. [ITER Joint Work Site, Garching (Germany)

    1998-07-01

    A design is proposed to steer the electron cyclotron heating and current drive power for ITER using rotatable, water-cooled mirrors and long-pressure hydraulic actuators, and to accommodate changes in length of the waveguide when the temperatures of the vacuum vessel and the cryostat change using waveguide bellows. An alternative concept is also introduced that requires no moving parts within the ITER cryostat and that utilizes wave reconstruction within the waveguide to effect the steering. (author)

  16. Threshold power and energy confinement for ITER

    Energy Technology Data Exchange (ETDEWEB)

    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. Efficient iterative adaptive pole placement algorithm

    Institute of Scientific and Technical Information of China (English)

    李俊民; 李靖; 杨磊

    2004-01-01

    An iterative adaptive pole placement algorithm is presented. The stability and the convergence of the algorithm are respectively established. Since one-step iterative formulation in computing controller's parameters is used, the on-line computation cost is greatly reduced with respected to the traditional algorithm. The algorithm with the feed-forward can follow arbitrarily bounded output. The algorithm is also extended to multivariate case. Simulation examples show the efficiency and robustness of the algorithm.

  18. Iterative consolidation of unorganized point clouds.

    Science.gov (United States)

    Liu, Shengjun; Chan, Kwan-Chung; Wang, Charlie C L

    2012-01-01

    Unorganized point clouds obtained from 3D shape acquisition devices usually present noise, outliers, and nonuniformities. The proposed framework consolidates unorganized points through an iterative procedure of interlaced downsampling and upsampling. Selection operations remove outliers while preserving geometric details. The framework improves the uniformity of points by moving the downsampled particles and refining point samples. Surface extrapolation fills missed regions. Moreover, an adaptive sampling strategy speeds up the iterations. Experimental results demonstrate the framework's effectiveness.

  19. Accelerated Schwarz iterations for Helmholtz equation

    Science.gov (United States)

    Nagid, Nabila; Belhadj, Hassan; Amattouch, Mohamed Ridouan

    2017-01-01

    In this paper, the Restricted additive Schwarz (RAS) method is applied to solve Helmholtz equation. To accelerate the RAS iterations, we propose to apply the vector ɛ-algorithm. Some convergence analysis of the proposed method is presented, and applied succeffully to Helmholtz problem. The obtained results show the efficiency of the proposed approach. Moreover, the algorithm yields much faster convergence than the classical Schwarz iterations.

  20. IMM Iterated Extended Particle Filter Algorithm

    OpenAIRE

    Yang Wan; Shouyong Wang; Xing Qin

    2013-01-01

    In order to solve the tracking problem of radar maneuvering target in nonlinear system model and non-Gaussian noise background, this paper puts forward one interacting multiple model (IMM) iterated extended particle filter algorithm (IMM-IEHPF). The algorithm makes use of multiple modes to model the target motion form to track any maneuvering target and each mode uses iterated extended particle filter (IEHPF) to deal with the state estimation problem of nonlinear non-Gaussian system. IEH...

  1. Algorithmic Optimisations for Iterative Deconvolution Methods

    OpenAIRE

    Welk, Martin; Erler, Martin

    2013-01-01

    We investigate possibilities to speed up iterative algorithms for non-blind image deconvolution. We focus on algorithms in which convolution with the point-spread function to be deconvolved is used in each iteration, and aim at accelerating these convolution operations as they are typically the most expensive part of the computation. We follow two approaches: First, for some practically important specific point-spread functions, algorithmically efficient sliding window or list processing tech...

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

    Science.gov (United States)

    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

  3. Development and test of prototype components for ITER; Entwicklung und Test von Prototypkomponenten fuer ITER

    Energy Technology Data Exchange (ETDEWEB)

    Biel, Wolfgang; Behr, Wilfried; Castano-Bardawil, David; and others

    2015-08-15

    The scientific program of the project is divided into the following partial projects: (1.) ITER Diagnostic Port Plug for the charge-exchange spectroscopy (CXRS) with the subthemes: (a) Development of prototypes for critical mechanical components, (b) development of a roboter for the laser welding of vacuum seals and pipings at the Port Plug, (c) mirror studies, (d) CXRS prototype spectrometer, (2.) ITER tritium retention diagnostics (TR), (3.) ITER disruption mitigation ventile (DMV).

  4. ITER Remote Maintenance System (IRMS) lifecycle management

    Energy Technology Data Exchange (ETDEWEB)

    Tesini, Alessandro, E-mail: alessandro.tesini@iter.org [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Otto' , Bede [Oxford Technologies Ltd, 7, Nuffield Way, Abingdon, Oxon OX14 1RJ (United Kingdom); Blight, John [FAAST 31c Allee de la Granette, 13600 Ceyreste (France); Choi, Chang-Hwan; Friconneau, Jean-Pierre; Gotewal, Krishan Kumar; Hamilton, David [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Heckendorn, Frank [FD Technologies, PO Box 6686, Aiken, SC (United States); Martins, Jean-Pierre [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Marty, Thomas [Westinghouse, 122, avenue de Hambourg, 13008 Marseille (France); Nakahira, Masataka; Palmer, Jim; Subramanian, Rajendran [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2011-10-15

    The availability of the ITER machine to perform its scientific program is strongly dependent on the performance of the different Remote Handling (RH) systems constituting the ITER Remote Maintenance System (IRMS). The lifecycle of the IRMS will largely exceed 40 years from initial concept design and proof testing through to machine decommissioning. Such a long lifecycle requires that a rigorous approach is put in place to guarantee the technical capabilities of the highly innovative IRMS, its efficiency and its availability. For this purpose, an IRMS System Engineering and IRMS lifecycle management approach has been adopted by ITER. The approach aims at ensuring the IRMS full operability and availability at an acceptable cost of ownership over the full ITER machine assembly and operations period. The IRMS lifecycle management method described in this paper covers such subjects as specific requirements for IRMS design reviews, monitoring during manufacture, factory and site acceptance testing, integrated commissioning, decontamination, maintenance and re-qualification strategies, requirements for Integrated Logistical Support during operations. The updating and implementation of the IRMS lifecycle strategy and this procedure will be managed and monitored by the Remote Handling Integrated Product Team (RH-IPT). Although developed for the IRMS, the basic principles and procedures of lifecycle management could be applied to other ITER plant systems whose reliability and availability will be essential for the continued operation of the ITER machine.

  5. Effects of low- and high-frequency repetitive magnetic stimulation on neuronal cell proliferation and growth factor expression: A preliminary report.

    Science.gov (United States)

    Lee, Ji Yong; Park, Hyung Joong; Kim, Ji Hyun; Cho, Byung Pil; Cho, Sung-Rae; Kim, Sung Hoon

    2015-09-14

    Repetitive magnetic stimulation is a neuropsychiatric and neurorehabilitation tool that can be used to investigate the neurobiology of sensory and motor functions. Few studies have examined the effects of repetitive magnetic stimulation on the modulation of neurotrophic/growth factors and neuronal cells in vitro. Therefore, the current study examined the differential effects of repetitive magnetic stimulation on neuronal cell proliferation as well as various growth factor expression. Immortalized mouse neuroblastoma cells were used as the cell model in this study. Dishes of cultured cells were randomly divided into control, sham, low-frequency (0.5Hz, 1Tesla) and high-frequency (10Hz, 1Tesla) groups (n=4 dishes/group) and were stimulated for 3 days. Expression of neurotrophic/growth factors, Akt and Erk was investigated by Western blotting analysis 3 days after repetitive magnetic stimulation. Neuroblastoma cell proliferation was determined with a cell counting assay. There were differences in cell proliferation based on stimulus frequency. Low-frequency stimulation did not alter proliferation relative to the control, while high-frequency stimulation elevated proliferation relative to the control group. The expression levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), neurotrophin-3 (NT-3) and platelet-derived growth factor (PDGF) were elevated in the high-frequency magnetic stimulation group. Akt and Erk expression was also significantly elevated in the high-frequency stimulation group, while low-frequency stimulation decreased the expression of Akt and Erk compared to the control. In conclusion, we determined that different frequency magnetic stimulation had an influence on neuronal cell proliferation via regulation of Akt and ERK signaling pathways and the expression of growth factors such as BDNF, GDNF, NT-3 and PDGF. These findings represent a promising opportunity to gain insight into how different

  6. ITER fast ion collective Thomson scattering. Conceptual design of 60 GHz system

    DEFF Research Database (Denmark)

    Meo, Fernando; Bindslev, Henrik; Korsholm, Søren Bang

    The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma...... describes the two systems and their main components. Section 3 clarifies the impact of design parameters such as beam widths and scattering angle on the CTS measurements. With this in hand, the ITER measurement requirements are translated into constraints on the CTS system designs. An important result...

  7. Beyond ITER: neutral beams for a demonstration fusion reactor (DEMO) (invited).

    Science.gov (United States)

    McAdams, R

    2014-02-01

    In the development of magnetically confined fusion as an economically sustainable power source, International Tokamak Experimental Reactor (ITER) is currently under construction. Beyond ITER is the demonstration fusion reactor (DEMO) programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

  8. Qualification of Fin-Type Heat Exchangers for the ITER Current Leads

    CERN Document Server

    Ballarino, A; Bordini, B; Devred, A; Ding, K; Niu, E; Sitko, M; Taylor, T; Yang, Y; Zhou, T

    2015-01-01

    The ITER current leads will transfer large currents of up to 68 kA into the biggest superconducting magnets ever built. Following the development of prototypes and targeted trials of specific manufacturing processes through mock-ups, the ASIPP (Chinese Institute of Plasma Physics) is preparing for the series fabrication. A key component of the ITER HTS current leads are the resistive heat exchangers. Special R&D was conducted for these components at CERN and ASIPP in support of their designs. In particular several mock-ups were built and tested in room temperature gas to measure the dynamic pressure drop and compare to 3D CFD models.

  9. Beyond ITER: Neutral beams for a demonstration fusion reactor (DEMO) (invited)

    Energy Technology Data Exchange (ETDEWEB)

    McAdams, R., E-mail: roy.mcadams@ccfe.ac.uk [EURATOM/CCFE Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)

    2014-02-15

    In the development of magnetically confined fusion as an economically sustainable power source, International Tokamak Experimental Reactor (ITER) is currently under construction. Beyond ITER is the demonstration fusion reactor (DEMO) programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

  10. Paradigm Changes in High Temperature Plasma Physics Research and Implications for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hyeon K. Park

    2008-02-22

    Significant high temperature plasma research in both the magnetic and inertial confinement regimes led to the official launching of the International Thermonuclear Experimental Reactor (ITER) project which is aimed at challenging controlled fusion power for human kind. In particular, such an endeavor originated from the fruitful research outcomes from the world wide magnetic confinement devices (primarily based on the Tokamak approach) mainly in advanced countries (US, EU, and Japan). In recent years, all new steady state capable Tokamak devices are operated and/or constructed in Asian countries and incidentally, the majority of the ITER consortium consists of Asian countries. This provides an opportunity to revisit the unresolved essential physics issues and/or extend the understanding of the transient physics to the required steady state operation so that ITER can benefit from these efforts. The core physics of a magnetically confined hot plasma has two essential components; plasma stability and cross-field energy transport physics. Complete understanding of these two areas is critical for the successful operation of ITER and perhaps, Demo reactor construction. In order to have stable high beta plasmas with a sufficiently long confinement time, the physics of an abrupt disruption and sudden deterioration of the energy transport must be understood and conquered. Physics issues associated with transient harmful MHD behavior and turbulence based energy transport are extremely complicated and theoretical understanding needs a clear validation and verification with a new research approach such as a multi-dimensional visualization.

  11. Contribution of Tore Supra in preparation of ITER

    Science.gov (United States)

    Saoutic, B.; Abiteboul, J.; Allegretti, L.; Allfrey, S.; Ané, J. M.; Aniel, T.; Argouarch, A.; Artaud, J. F.; Aumenier, M. H.; Balme, S.; Basiuk, V.; Baulaigue, O.; Bayetti, P.; Bécoulet, A.; Bécoulet, M.; Benkadda, M. S.; Benoit, F.; Berger-by, G.; Bernard, J. M.; Bertrand, B.; Beyer, P.; Bigand, A.; Blum, J.; Boilson, D.; Bonhomme, G.; Bottollier-Curtet, H.; Bouchand, C.; Bouquey, F.; Bourdelle, C.; Bourmaud, S.; Brault, C.; Brémond, S.; Brosset, C.; Bucalossi, J.; Buravand, Y.; Cara, P.; Catherine-Dumont, V.; Casati, A.; Chantant, M.; Chatelier, M.; Chevet, G.; Ciazynski, D.; Ciraolo, G.; Clairet, F.; Coatanea-Gouachet, M.; Colas, L.; Commin, L.; Corbel, E.; Corre, Y.; Courtois, X.; Dachicourt, R.; Dapena Febrer, M.; Davi Joanny, M.; Daviot, R.; De Esch, H.; Decker, J.; Decool, P.; Delaporte, P.; Delchambre, E.; Delmas, E.; Delpech, L.; Desgranges, C.; Devynck, P.; Dittmar, T.; Doceul, L.; Douai, D.; Dougnac, H.; Duchateau, J. L.; Dugué, B.; Dumas, N.; Dumont, R.; Durocher, A.; Duthoit, F. X.; Ekedahl, A.; Elbeze, D.; El Khaldi, M.; Escourbiac, F.; Faisse, F.; Falchetto, G.; Farge, M.; Farjon, J. L.; Faury, M.; Fedorczak, N.; Fenzi-Bonizec, C.; Firdaouss, M.; Frauel, Y.; Garbet, X.; Garcia, J.; Gardarein, J. L.; Gargiulo, L.; Garibaldi, P.; Gauthier, E.; Gaye, O.; Géraud, A.; Geynet, M.; Ghendrih, P.; Giacalone, I.; Gibert, S.; Gil, C.; Giruzzi, G.; Goniche, M.; Grandgirard, V.; Grisolia, C.; Gros, G.; Grosman, A.; Guigon, R.; Guilhem, D.; Guillerminet, B.; Guirlet, R.; Gunn, J.; Gurcan, O.; Hacquin, S.; Hatchressian, J. C.; Hennequin, P.; Hernandez, C.; Hertout, P.; Heuraux, S.; Hillairet, J.; Hoang, G. T.; Honore, C.; Houry, M.; Hutter, T.; Huynh, P.; Huysmans, G.; Imbeaux, F.; Joffrin, E.; Johner, J.; Jourd'Heuil, L.; Katharria, Y. S.; Keller, D.; Kim, S. H.; Kocan, M.; Kubic, M.; Lacroix, B.; Lamaison, V.; Latu, G.; Lausenaz, Y.; Laviron, C.; Leroux, F.; Letellier, L.; Lipa, M.; Litaudon, X.; Loarer, T.; Lotte, P.; Madeleine, S.; Magaud, P.; Maget, P.; Magne, R.; Manenc, L.; Marandet, Y.; Marbach, G.; Maréchal, J. L.; Marfisi, L.; Martin, C.; Martin, G.; Martin, V.; Martinez, A.; Martins, J. P.; Masset, R.; Mazon, D.; Mellet, N.; Mercadier, L.; Merle, A.; Meshcheriakov, D.; Meyer, O.; Million, L.; Missirlian, M.; Mollard, P.; Moncada, V.; Monier-Garbet, P.; Moreau, D.; Moreau, P.; Morini, L.; Nannini, M.; Naiim Habib, M.; Nardon, E.; Nehme, H.; Nguyen, C.; Nicollet, S.; Nouilletas, R.; Ohsako, T.; Ottaviani, M.; Pamela, S.; Parrat, H.; Pastor, P.; Pecquet, A. L.; Pégourié, B.; Peysson, Y.; Porchy, I.; Portafaix, C.; Preynas, M.; Prou, M.; Raharijaona, J. M.; Ravenel, N.; Reux, C.; Reynaud, P.; Richou, M.; Roche, H.; Roubin, P.; Sabot, R.; Saint-Laurent, F.; Salasca, S.; Samaille, F.; Santagiustina, A.; Sarazin, Y.; Semerok, A.; Schlosser, J.; Schneider, M.; Schubert, M.; Schwander, F.; Ségui, J. L.; Selig, G.; Sharma, P.; Signoret, J.; Simonin, A.; Song, S.; Sonnendruker, E.; Sourbier, F.; Spuig, P.; Tamain, P.; Tena, M.; Theis, J. M.; Thouvenin, D.; Torre, A.; Travère, J. M.; Tsitrone, E.; Vallet, J. C.; Van Der Plas, E.; Vatry, A.; Verger, J. M.; Vermare, L.; Villecroze, F.; Villegas, D.; Volpe, R.; Vulliez, K.; Wagrez, J.; Wauters, T.; Zani, L.; Zarzoso, D.; Zou, X. L.

    2011-09-01

    Tore Supra routinely addresses the physics and technology of very long-duration plasma discharges, thus bringing precious information on critical issues of long pulse operation of ITER. A new ITER relevant lower hybrid current drive (LHCD) launcher has allowed coupling to the plasma a power level of 2.7 MW for 78 s, corresponding to a power density close to the design value foreseen for an ITER LHCD system. In accordance with the expectations, long distance (10 cm) power coupling has been obtained. Successive stationary states of the plasma current profile have been controlled in real-time featuring (i) control of sawteeth with varying plasma parameters, (ii) obtaining and sustaining a 'hot core' plasma regime, (iii) recovery from a voluntarily triggered deleterious magnetohydrodynamic regime. The scrape-off layer (SOL) parameters and power deposition have been documented during L-mode ramp-up phase, a crucial point for ITER before the X-point formation. Disruption mitigation studies have been conducted with massive gas injection, evidencing the difference between He and Ar and the possible role of the q = 2 surface in limiting the gas penetration. ICRF assisted wall conditioning in the presence of magnetic field has been investigated, culminating in the demonstration that this conditioning scheme allows one to recover normal operation after disruptions. The effect of the magnetic field ripple on the intrinsic plasma rotation has been studied, showing the competition between turbulent transport processes and ripple toroidal friction. During dedicated dimensionless experiments, the effect of varying the collisionality on turbulence wavenumber spectra has been documented, giving new insight into the turbulence mechanism. Turbulence measurements have also allowed quantitatively comparing experimental results with predictions by 5D gyrokinetic codes: numerical results simultaneously match the magnitude of effective heat diffusivity, rms values of density fluctuations

  12. EAST and its technical program in preparation to ITER

    Energy Technology Data Exchange (ETDEWEB)

    Li Jiangang [Chinese Academy of Sciences (China). Inst. of Plasma Physics

    2007-07-01

    EAST is the first Tokamak using superconducting magnet technology similar to that required in ITER. The successful construction and commissioning of EAST could provide many useful experiences for ITER. EAST got its first plasma on Sept. 26, 2006. Experiments have been carried out during last October and this January. Up to 500kA divertor plasma has been obtained. Up/Down single null, double null configurations have been obtained with elongation close to 2 and elongation over 0.6. Plasma duration was close to 10s. The success in achieving various shaped diverted plasma confirms capability of the superconducting poloidal magnets and plasma control algorithm with the EAST new features. Efforts have been made for machine safety, reliability and capacity during commissioning. All design parameters of machine reached their full values, such as toroidal field 3.5 T, 20 kA/s PF coil ramping rate, in the end of commissioning. Of particular interest have been focused on the operational experience with quench detection systems, reliable interlock and safety system, the plasma control capability of the superconducting PF coils and the use of HTc current leads. The new machine shows its unique features during experiments, which are well suited to answer a number of important issues for ITER operations and developments towards DEMO. Plasma initiation, ramp up and control with constraints of superconducting coils. Very low plasma ramp rate of 0.1MA/s during start up phase have been obtained with assistant of LHW on a boronized wall condition. Effects of AC losses and disruptions on the superconducting systems have been evaluated during plasma discharges. Two wall conditioning techniques, GDC and ICR, have been used and compared. ICR technique has been extensively used for wall cleaning, recycling control, and boronization with very wide operation pressure (1 x 10-4Pa-5Pa). Further developments of EAST hardware will make more contribution for ITER construction and operation, such

  13. Sensitivity of alpha-particle-driven Alfven eigenmodes to q-profile variation in ITER scenarios

    CERN Document Server

    Rodrigues, P; Fazendeiro, L; Ferreira, J; Coelho, R; Nabais, F; Borba, D; Polevoi, N F Loureiro A R; Pinches, S D; Sharapov, S E

    2016-01-01

    An hybrid ideal-MHD/drift-kinetic approach to assess the stability of alpha-particle-driven Alfven eigenmodes in burning plasmas is used to show that certain foreseen ITER scenarios, namely the $I_\\mathrm{p} = 15$ MA baseline scenario with very low and broad core magnetic shear, are sensitive to small changes in the background magnetic equilibrium. Slight perturbations (of the order of 1%) in the total plasma current are seen to cause large variations in the growth rate, toroidal mode number, and radial location of the most unstable eigenmodes found. The observed sensitivity is shown to proceed from the very low magnetic shear values attained throughout the plasma core.

  14. Detection of occult endoleaks after endovascular treatment of abdominal aortic aneurysm using magnetic resonance imaging with a blood pool contrast agent: preliminary observations.

    NARCIS (Netherlands)

    Cornelissen, Sandra; Prokop, M.; Verhagen, H.J.; Adriaensen, M.E.; Moll, F.L.; Bartels, L.W.

    2010-01-01

    OBJECTIVE: To determine whether blood pool contrast agent-enhanced magnetic resonance imaging (MRI) can visualize endoleaks that are occult on computed tomography (CT) in patients with nonshrinking aneurysms after endovascular aneurysm repair. MATERIALS AND METHODS: Written informed consent was obta

  15. Preliminary Evidence of the Effects of High-frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Swallowing Functions in Post-Stroke Individuals with Chronic Dysphagia

    Science.gov (United States)

    Cheng, Ivy K. Y.; Chan, Karen M. K.; Wong, C. S.; Cheung, Raymond T. F.

    2015-01-01

    Background: There is growing evidence of potential benefits of repetitive transcranial magnetic stimulation (rTMS) in the rehabilitation of dysphagia. However, the site and frequency of stimulation for optimal effects are not clear. Aims: The aim of this pilot study is to investigate the short-term effects of high-frequency 5 Hz rTMS applied to…

  16. Low-Frequency Repetitive Transcranial Magnetic Stimulation and Intensive Occupational Therapy for Poststroke Patients with Upper Limb Hemiparesis: Preliminary Study of a 15-Day Protocol

    Science.gov (United States)

    Kakuda, Wataru; Abo, Masahiro; Kobayashi, Kazushige; Momosaki, Ryo; Yokoi, Aki; Fukuda, Akiko; Ishikawa, Atsushi; Ito, Hiroshi; Tominaga, Ayumi

    2010-01-01

    The purpose of the study was to determine the safety and feasibility of a 15-day protocol of low-frequency repetitive transcranial magnetic stimulation (rTMS) combined with intensive occupational therapy (OT) on motor function and spasticity in hemiparetic upper limbs in poststroke patients. Fifteen poststroke patients (age at study entry 55 [plus…

  17. Preliminary Evidence of the Effects of High-frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Swallowing Functions in Post-Stroke Individuals with Chronic Dysphagia

    Science.gov (United States)

    Cheng, Ivy K. Y.; Chan, Karen M. K.; Wong, C. S.; Cheung, Raymond T. F.

    2015-01-01

    Background: There is growing evidence of potential benefits of repetitive transcranial magnetic stimulation (rTMS) in the rehabilitation of dysphagia. However, the site and frequency of stimulation for optimal effects are not clear. Aims: The aim of this pilot study is to investigate the short-term effects of high-frequency 5 Hz rTMS applied to…

  18. Detection of occult endoleaks after endovascular treatment of abdominal aortic aneurysm using magnetic resonance imaging with a blood pool contrast agent: preliminary observations.

    NARCIS (Netherlands)

    Cornelissen, Sandra; Prokop, M.; Verhagen, H.J.; Adriaensen, M.E.; Moll, F.L.; Bartels, L.W.

    2010-01-01

    OBJECTIVE: To determine whether blood pool contrast agent-enhanced magnetic resonance imaging (MRI) can visualize endoleaks that are occult on computed tomography (CT) in patients with nonshrinking aneurysms after endovascular aneurysm repair. MATERIALS AND METHODS: Written informed consent was obta

  19. Direct design of freeform surfaces and freeform imaging systems with a point-by-point three-dimensional construction-iteration method.

    Science.gov (United States)

    Yang, Tong; Zhu, Jun; Wu, Xiaofei; Jin, Guofan

    2015-04-20

    In this paper, we proposed a general direct design method for three-dimensional freeform surfaces and freeform imaging systems based on a construction-iteration process. In the preliminary surfaces-construction process, the coordinates as well as the surface normals of the data points on the multiple freeform surfaces can be calculated directly considering the rays of multiple fields and different pupil coordinates. Then, an iterative process is employed to significantly improve the image quality or achieve a better mapping relationship of the light rays. Three iteration types which are normal iteration, negative feedback and successive approximation are given. The proposed construction-iteration method is applied in the design of an easy aligned, low F-number off-axis three-mirror system. The primary and tertiary mirrors can be fabricated on a single substrate and form a single element in the final system. The secondary mirror is simply a plane mirror. With this configuration, the alignment difficulty of a freeform system can be greatly reduced. After the preliminary surfaces-construction stage, the freeform surfaces in the optical system can be generated directly from an initial planar system. Then, with the iterative process, the average RMS spot diameter decreased by 75.4% compared with the system before iterations, and the maximum absolute distortion decreased by 94.2%. After further optimization with optical design software, good image quality which is closed to diffraction-limited is achieved.

  20. Recent ASDEX Upgrade research in support of ITER and DEMO

    Science.gov (United States)

    H. Zohmthe ASDEX Upgrade Team; the EUROfusion MST1 Team

    2015-10-01

    Recent experiments on the ASDEX Upgrade tokamak aim at improving the physics base for ITER and DEMO to aid the machine design and prepare efficient operation. Type I edge localized mode (ELM) mitigation using resonant magnetic perturbations (RMPs) has been shown at low pedestal collisionality (νped\\ast PLH occurs indicates that ITER could take advantage of it to initiate H-mode at lower density than that of the final Q = 10 operational point. Core density fluctuation measurements resolved in radius and wave number show that an increase of R/LTe introduced by off-axis electron cyclotron resonance heating (ECRH) mainly increases the large scale fluctuations. The radial variation of the fluctuation level is in agreement with simulations using the GENE code. Fast particles are shown to undergo classical slowing down in the absence of large scale magnetohydrodynamic (MHD) events and for low heating power, but show signs of anomalous radial redistribution at large heating power, consistent with a broadened off-axis neutral beam current drive current profile under these conditions. Neoclassical tearing mode (NTM) suppression experiments using electron cyclotron current drive (ECCD) with feedback controlled deposition have allowed to test several control strategies for ITER, including automated control of (3,2) and (2,1) NTMs during a single discharge. Disruption mitigation studies using massive gas injection (MGI) can show an increased fuelling efficiency with high field side injection, but a saturation of the fuelling efficiency is observed at high injected mass as needed for runaway electron suppression. Large locked modes can significantly decrease the fuelling efficiency and increase the asymmetry of radiated power during MGI mitigation. Concerning power exhaust, the partially detached ITER divertor scenario has been demonstrated at Psep/R = 10 MW m-1 in ASDEX Upgrade, with a peak time averaged target load around 5 MW m-2, well consistent with the component limits

  1. Final Scientific/Technical Report for DOE/EERE project Advanced Magnetic Refrigerant Materials

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Francis

    2014-06-30

    A team led by GE Global Research developed new magnetic refrigerant materials needed to enhance the commercialization potential of residential appliances such as refrigerators and air conditioners based on the magnetocaloric effect (a nonvapor compression cooling cycle). The new magnetic refrigerant materials have potentially better performance at lower cost than existing materials, increasing technology readiness level. The performance target of the new magnetocaloric material was to reduce the magnetic field needed to achieve 4 °C adiabatic temperature change from 1.5 Tesla to 0.75 Tesla. Such a reduction in field minimizes the cost of the magnet assembly needed for a magnetic refrigerator. Such a reduction in magnet assembly cost is crucial to achieving commercialization of magnetic refrigerator technology. This project was organized as an iterative alloy development effort with a parallel material modeling task being performed at George Washington University. Four families of novel magnetocaloric alloys were identified, screened, and assessed for their performance potential in a magnetic refrigeration cycle. Compositions from three of the alloy families were manufactured into regenerator components. At the beginning of the project a previously studied magnetocaloric alloy was selected for manufacturing into the first regenerator component. Each of the regenerators was tested in magnetic refrigerator prototypes at a subcontractor at at GE Appliances. The property targets for operating temperature range, operating temperature control, magnetic field sensitivity, and corrosion resistance were met. The targets for adiabatic temperature change and thermal hysteresis were not met. The high thermal hysteresis also prevented the regenerator components from displaying measurable cooling power when tested in prototype magnetic refrigerators. Magnetic refrigerant alloy compositions that were predicted to have low hysteresis were not attainable with conventional alloy

  2. A New Iterative Scheme of Modified Mann Iteration in Banach Space

    Directory of Open Access Journals (Sweden)

    Jinzuo Chen

    2014-01-01

    Full Text Available We introduce the modified iterations of Mann's type for nonexpansive mappings and asymptotically nonexpansive mappings to have the strong convergence in a uniformly convex Banach space. We study approximation of common fixed point of asymptotically nonexpansive mappings in Banach space by using a new iterative scheme. Applications to the accretive operators are also included.

  3. Picard iteration converges faster than Mann iteration for a class of quasi-contractive operators

    Directory of Open Access Journals (Sweden)

    Vasile Berinde

    2004-06-01

    Full Text Available In the class of quasi-contractive operators satisfying Zamfirescu's conditions, the most used fixed point iterative methods, that is, the Picard, Mann, and Ishikawa iterations, are all known to be convergent to the unique fixed point. In this paper, the comparison of the first two methods with respect to their convergence rate is obtained.

  4. Toroidal modeling of plasma response to RMP fields in ITER

    Science.gov (United States)

    Li, L.; Liu, Y. Q.; Wang, N.; Kirk, A.; Koslowski, H. R.; Liang, Y.; Loarte, A.; Ryan, D.; Zhong, F. C.

    2017-04-01

    A systematic numerical study is carried out, computing the resistive plasma response to the resonant magnetic perturbation (RMP) fields for ITER plasmas, utilizing the toroidal code MARS-F (Liu et al 2000 Phys. Plasmas 7 3681). A number of factors are taken into account, including the variation of the plasma scenarios (from 15 MA Q = 10 inductive scenario to the 9 MA Q = 5 steady state scenario), the variation of the toroidal spectrum of the applied fields (n = 1, 2, 3, 4, with n being the toroidal mode number), the amplitude and phase variation of the currents in three rows of the RMP coils as designed for ITER, and finally a special case of mixed toroidal spectrum between the n = 3 and n = 4 RMP fields. Two-dimensional parameter scans, for the edge safety factor and the coil phasing between the upper and lower rows of coils, yield ‘optimal’ curves that maximize a set of figures of merit, that are defined in this work to measure the plasma response. Other two-dimensional scans of the relative coil current phasing among three rows of coils, at fixed coil currents amplitude, reveal a single optimum for each coil configuration with a given n number, for the 15 MA ITER inductive plasma. On the other hand, scanning of the coil current amplitude, at fixed coil phasing, shows either synergy or cancellation effect, for the field contributions between the off-middle rows and the middle row of the RMP coils. Finally, the mixed toroidal spectrum, by combining the n = 3 and the n = 4 RMP field, results in a substantial local reduction of the amplitude of the plasma surface displacement.

  5. Study of neutron spectrometers for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Kaellne, Jan

    2005-11-15

    A review is presented of the developments in the field of neutron emission spectrometry (NES) which is of relevance for identifying the role of NES diagnostics on ITER and selecting suitable instrumentation. Neutron spectrometers will be part of the ITER neutron diagnostic complement and this study makes a special effort to examine which performance characteristics the spectrometers should possess to provide the best burning plasma diagnostic information together with neutron cameras and neutron yield monitors. The performance of NES diagnostics is coupled to how much interface space can be provided which has lead to an interest to find compact instruments and their NES capabilities. This study assesses all known spectrometer types of potential interest for ITER and makes a ranking of their performance (as demonstrated or projected), which, in turn, are compared with ITER measurement requirements as a reference; the ratio of diagnostic performance to interface cost for different spectrometers is also discussed for different spectrometer types. The overall result of the study is an assessment of which diagnostic functions neutron measurements can provide in burning plasma fusion experiments on ITER and the role that NES can play depending on the category of instrument installed. Of special note is the result that much higher quality diagnostic information can be obtained from neutron measurements with total yield monitors, profile flux cameras and spectrometers when the synergy in the data is considered in the analysis and interpretation.

  6. Status of ITER neutron diagnostic development

    Science.gov (United States)

    Krasilnikov, A. V.; Sasao, M.; Kaschuck, Yu. A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V. S.; Popovichev, S.; Iguchi, T.; Jarvis, O. N.; Källne, J.; Fiore, C. L.; Roquemore, A. L.; Heidbrink, W. W.; Fisher, R.; Gorini, G.; Prosvirin, D. V.; Tsutskikh, A. Yu.; Donné, A. J. H.; Costley, A. E.; Walker, C. I.

    2005-12-01

    Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be measured well by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors (NFMs), neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The NFMs need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented.

  7. Study of a fibre optics current sensor for the measurement of plasma current in ITER

    Science.gov (United States)

    Wuilpart, Marc; Vanus, Benoit; Andrasan, Alina; Gusarov, Andrei; Moreau, Philippe; Mégret, Patrice

    2016-05-01

    In this article, we study the feasibility of using a fibre-optics current sensor (FOCS) for the measurement of plasma current in the future fusion reactor ITER. The sensor is based on a classical FOCS interrogator involving the measurement of the state of polarization rotation undergone by the light in presence of a magnetic field (Faraday effect) in an optical fibre surrounding the current and terminated by a Faraday mirror. We considered a uniformly spun optical fibre as the sensing element and we used the Stokes formalism to simulate the sensor. The objective of the simulations is to quantify the ratio LB/SP (beat length over the spun period of the spun fibre) enabling a measurement error in agreement with the ITER specifications. The simulator takes into account the temperature variations undergone by the measurement system under ITER operation. The simulation work showed that a LB/SP ratio of 19.2 is adequate.

  8. Progress with the ITER project activity in Russia

    Science.gov (United States)

    Krasilnikov, A. V.; Abdyuhanov, I. M.; Aleksandrov, E. V.; Alekseev, A. G.; Amosov, V. N.; Antonov, N. V.; Arkhipov, N. I.; Burdakov, A. V.; Chugunov, I. N.; Denisov, G. G.; Gervash, A. A.; Ivantsivskiy, M. V.; Kaschuk, Yu. A.; Khomyakov, S. E.; Krasilnikov, V. A.; Kupriyanov, I. B.; Kuzmin, E. G.; Kuznetsov, V. E.; Lelekhov, S. A.; Leshukov, A. Yu.; Litvak, A. G.; Makhankov, A. N.; Mazul, I. V.; Mokeev, A. N.; Mukhin, E. E.; Petrov, A. A.; Petrov, M. P.; Petrov, S. Ya.; Petrov, V. G.; Rodin, I. Yu.; Romannikov, A. N.; Rumyantsev, Yu. N.; Safronov, V. M.; Savrukhin, P. V.; Tronza, V. I.; Tugarinov, S. N.; Ustinov, A. L.; Vershkov, V. A.; Vdovin, V. L.; Vysotsky, V. S.; Zernov, S. N.; Zhitlukhin, A. M.; Zvonkov, A. V.

    2015-10-01

    Due to the development of the ITER project, the requirements of the technical parameters of the ITER systems were more precisely and practically determined to be at higher levels. The essential increase of the ITER system characteristics happened recently. A number of prototypes were manufactured and tests were carried out. The results of the development and manufacture of 25 ITER systems, subject to the Russian Federation's obligations in the ITER project, are described.

  9. Modelling of hybrid scenario: from present-day experiments towards ITER

    Science.gov (United States)

    Litaudon, X.; Voitsekhovitch, I.; Artaud, J. F.; Belo, P.; Bizarro, João P. S.; Casper, T.; Citrin, J.; Fable, E.; Ferreira, J.; Garcia, J.; Garzotti, L.; Giruzzi, G.; Hobirk, J.; Hogeweij, G. M. D.; Imbeaux, F.; Joffrin, E.; Koechl, F.; Liu, F.; Lönnroth, J.; Moreau, D.; Parail, V.; Schneider, M.; Snyder, P. B.; the ASDEX-Upgrade Team; Contributors, JET-EFDA; the EU-ITM ITER Scenario Modelling Group

    2013-07-01

    The ‘hybrid’ scenario is an attractive operating scenario for ITER since it combines long plasma duration with the reliability of the reference H-mode regime. We review the recent European modelling effort carried out within the Integrated Scenario Modelling group which aims at (i) understanding the underlying physics of the hybrid regime in ASDEX-Upgrade and JET and (ii) extrapolating them towards ITER. JET and ASDEX-Upgrade hybrid scenarios performed under different experimental conditions have been simulated in an interpretative and predictive way in order to address the current profile dynamics and its link with core confinement, the relative importance of magnetic shear, s, and E × B flow shear on the core turbulence, pedestal stability and H-L transition. The correlation of the improved confinement with an increased s/q at outer radii observed in JET and ASDEX-Upgrade discharges is consistent with the predictions based on the GLF23 model applied in the simulations of the ion and electron kinetic profiles. Projections to ITER hybrid scenarios have been carried out focusing on optimization of the heating/current drive schemes to reach and ultimately control the desired plasma equilibrium using ITER actuators. Firstly, access condition to the hybrid-like q-profiles during the current ramp-up phase has been investigated. Secondly, from the interpreted role of the s/q ratio, ITER hybrid scenario flat-top performance has been optimized through tailoring the q-profile shape and pedestal conditions. EPED predictions of pedestal pressure and width have been used as constraints in the interpretative modelling while the core heat transport is predicted by GLF23. Finally, model-based approach for real-time control of advanced tokamak scenarios has been applied to ITER hybrid regime for simultaneous magnetic and kinetic profile control.

  10. Detailed 3-D nuclear analysis of ITER blanket modules

    Energy Technology Data Exchange (ETDEWEB)

    Bohm, T.D., E-mail: tdbohm@wisc.edu [University of Wisconsin-Madison, Madison, WI (United States); Sawan, M.E.; Marriott, E.P.; Wilson, P.P.H. [University of Wisconsin-Madison, Madison, WI (United States); Ulrickson, M.; Bullock, J. [Sandia National Laboratories, Albuquerque, NM (United States)

    2014-10-15

    In ITER, the blanket modules (BM) are arranged around the plasma to provide thermal and nuclear shielding for the vacuum vessel (VV), magnets, and other components. As a part of the BM design process, nuclear analysis is required to determine the level of nuclear heating, helium production, and radiation damage in the BM. Additionally, nuclear heating in the VV is also important for assessing the BM design. We used the CAD based DAG-MCNP5 transport code to analyze detailed models inserted into a 40-degree partially homogenized ITER global model. The regions analyzed include BM01, the neutral beam injection (NB) region, and the upper port region. For BM01, the results show that He production meets the limit necessary for re-welding, and the VV heating behind BM01 is acceptable. For the NBI region, the VV nuclear heating behind the NB region exceeds the design limit by a factor of two. For the upper port region, the nuclear heating of the VV exceeds the design limit by up to 20%. The results presented in this work are being used to modify the BM design in the cases where limits are exceeded.

  11. EC power sources: European technological developments towards ITER

    Energy Technology Data Exchange (ETDEWEB)

    Bonicelli, T. [EFDA Close Support Unit Garching, Boltzmannstr 2, 85748 Garching (Germany)], E-mail: tullio.bonicelli@tech.efda.org; Alberti, S. [EPFL-CRPP, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Cirant, S. [Istituto di Fisica del Plasma EURATOM-ENEA-CNR Association, Milan (Italy); Dormicchi, O. [Ansaldo Superconduttori SpA, C.so Perrone, Genoa (Italy); Fasel, D.; Hogge, J.P. [EPFL-CRPP, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Illy, S.; Jin, J. [Forschungszentrum Karlsruhe, Association EURATOM FZK, IHM, 76344 Eggenstein-Leopoldshafen (Germany); Lievin, C. [Thales Electron Devices (TED), 2 Rue de Latecoere, F-78141 Velizy-Villacoublay (France); Mondino, P.L. [EFDA Close Support Unit Garching, Boltzmannstr 2, 85748 Garching (Germany); Piosczyk, B.; Rzesnicki, T. [Forschungszentrum Karlsruhe, Association EURATOM FZK, IHM, 76344 Eggenstein-Leopoldshafen (Germany); Santinelli, M. [ENEA Frascati, Via E Fermi 45, 00044 Frascati, Rome (Italy); Taddia, G. [OCEM, Via 2 Agosto 1980 11, 40016 San Giorgio di Piano (Italy); Thumm, M. [Forschungszentrum Karlsruhe, Association EURATOM FZK, IHM, 76344 Eggenstein-Leopoldshafen (Germany); Tran, M.Q. [EPFL-CRPP, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland)

    2007-10-15

    The activities in Europe towards the development of the EC power sources for ITER are centered on the development of a 170 GHz, 2 MW, CW coaxial cavity gyrotron of collector potential depressed (CPD) type. A gyrotron with a higher unit power than the ITER reference (1 MW) would yield a reduction of the installation costs, a more compact launcher design and, if required, an increase of the power delivered through one port. Tests proving the principle were successfully performed on a short-pulse experimental gyrotron delivering up to 2.2 MW in single mode. Following this success, a coordinated and fully consistent programme of development has been launched. The first industrial 2 MW prototype is now at an advanced stage of construction. The associated superconductive magnet producing 6.86 T on the cavity axis is also being procured. Dummy loads suitable for short and CW operation are also part of the development effort. Finally, a new EC test facility, with the features necessary for the testing of the gyrotron up to full power in CW, has been established and includes a fully solid-state power supply system.0.

  12. Correction of spin diffusion during iterative automated NOE assignment.

    Science.gov (United States)

    Linge, Jens P; Habeck, Michael; Rieping, Wolfgang; Nilges, Michael

    2004-04-01

    Indirect magnetization transfer increases the observed nuclear Overhauser enhancement (NOE) between two protons in many cases, leading to an underestimation of target distances. Wider distance bounds are necessary to account for this error. However, this leads to a loss of information and may reduce the quality of the structures generated from the inter-proton distances. Although several methods for spin diffusion correction have been published, they are often not employed to derive distance restraints. This prompted us to write a user-friendly and CPU-efficient method to correct for spin diffusion that is fully integrated in our program ambiguous restraints for iterative assignment (ARIA). ARIA thus allows automated iterative NOE assignment and structure calculation with spin diffusion corrected distances. The method relies on numerical integration of the coupled differential equations which govern relaxation by matrix squaring and sparse matrix techniques. We derive a correction factor for the distance restraints from calculated NOE volumes and inter-proton distances. To evaluate the impact of our spin diffusion correction, we tested the new calibration process extensively with data from the Pleckstrin homology (PH) domain of Mus musculus beta-spectrin. By comparing structures refined with and without spin diffusion correction, we show that spin diffusion corrected distance restraints give rise to structures of higher quality (notably fewer NOE violations and a more regular Ramachandran map). Furthermore, spin diffusion correction permits the use of tighter error bounds which improves the distinction between signal and noise in an automated NOE assignment scheme.

  13. Cyclic game dynamics driven by iterated reasoning

    CERN Document Server

    Frey, Seth

    2012-01-01

    Recent theories from complexity science argue that complex dynamics are ubiquitous in social and economic systems. These claims emerge from the analysis of individually simple agents whose collective behavior is surprisingly complicated. However, game theorists have argued that iterated reasoning-our ability to think through what you think I think you think-will prevent complex dynamics and facilitate convergence to classic equilibria. We report stable and efficient periodic behavior in human groups playing the Mod Game, a multi-player game similar to Rock-Paper-Scissors. The game rewards subjects for thinking exactly one step ahead of others in their group. Groups that play this game exhibit cycles that are inconsistent with any fixed-point equilibrium concept. These cycles are driven by a "hopping" behavior that can only be explained by iterated reasoning. If iterated reasoning can be complicit in complex dynamics, then game cycles and chaos may realistically be driving fluctuations in real-world social and...

  14. A Logical Characterization of Iterated Admissibility

    CERN Document Server

    Halpern, Joseph Y

    2009-01-01

    Brandenburger, Friedenberg, and Keisler provide an epistemic characterization of iterated admissibility (i.e., iterated deletion of weakly dominated strategies) where uncertainty is represented using LPSs (lexicographic probability sequences). Their characterization holds in a rich structure called a complete structure, where all types are possible. Here, a logical charaacterization of iterated admisibility is given that involves only standard probability and holds in all structures, not just complete structures. A stronger notion of strong admissibility is then defined. Roughly speaking, strong admissibility is meant to capture the intuition that "all the agent knows" is that the other agents satisfy the appropriate rationality assumptions. Strong admissibility makes it possible to relate admissibility, canonical structures (as typically considered in completeness proofs in modal logic), complete structures, and the notion of ``all I know''.

  15. Iterative Reconstruction of Coded Source Neutron Radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Bingham, Philip R [ORNL; Gregor, Jens [University of Tennessee, Knoxville (UTK)

    2013-01-01

    Use of a coded source facilitates high-resolution neutron imaging through magnifications but requires that the radiographic data be deconvolved. A comparison of direct deconvolution with two different iterative algorithms has been performed. One iterative algorithm is based on a maximum likelihood estimation (MLE)-like framework and the second is based on a geometric model of the neutron beam within a least squares formulation of the inverse imaging problem. Simulated data for both uniform and Gaussian shaped source distributions was used for testing to understand the impact of non-uniformities present in neutron beam distributions on the reconstructed images. Results indicate that the model based reconstruction method will match resolution and improve on contrast over convolution methods in the presence of non-uniform sources. Additionally, the model based iterative algorithm provides direct calculation of quantitative transmission values while the convolution based methods must be normalized base on known values.

  16. Advances in iterative methods for nonlinear equations

    CERN Document Server

    Busquier, Sonia

    2016-01-01

    This book focuses on the approximation of nonlinear equations using iterative methods. Nine contributions are presented on the construction and analysis of these methods, the coverage encompassing convergence, efficiency, robustness, dynamics, and applications. Many problems are stated in the form of nonlinear equations, using mathematical modeling. In particular, a wide range of problems in Applied Mathematics and in Engineering can be solved by finding the solutions to these equations. The book reveals the importance of studying convergence aspects in iterative methods and shows that selection of the most efficient and robust iterative method for a given problem is crucial to guaranteeing a good approximation. A number of sample criteria for selecting the optimal method are presented, including those regarding the order of convergence, the computational cost, and the stability, including the dynamics. This book will appeal to researchers whose field of interest is related to nonlinear problems and equations...

  17. SPARSE ELECTROMAGNETIC IMAGING USING NONLINEAR LANDWEBER ITERATIONS

    KAUST Repository

    Desmal, Abdulla

    2015-07-29

    A scheme for efficiently solving the nonlinear electromagnetic inverse scattering problem on sparse investigation domains is described. The proposed scheme reconstructs the (complex) dielectric permittivity of an investigation domain from fields measured away from the domain itself. Least-squares data misfit between the computed scattered fields, which are expressed as a nonlinear function of the permittivity, and the measured fields is constrained by the L0/L1-norm of the solution. The resulting minimization problem is solved using nonlinear Landweber iterations, where at each iteration a thresholding function is applied to enforce the sparseness-promoting L0/L1-norm constraint. The thresholded nonlinear Landweber iterations are applied to several two-dimensional problems, where the ``measured\\'\\' fields are synthetically generated or obtained from actual experiments. These numerical experiments demonstrate the accuracy, efficiency, and applicability of the proposed scheme in reconstructing sparse profiles with high permittivity values.

  18. Iterative Contracts as Proactive Law Instruments

    DEFF Research Database (Denmark)

    Henschel, René Franz

    2012-01-01

    The purpose of this article is to analyse the use of proactive law in contracts illustrated by the use of a particular type of contract within the IT industry, the so-called iterative contract. This type of contract has its root in a special software development process called iterative....... This software development process has driven the need for a new contract design that supports the product life cycle better than the traditional contracts. As will be shown in the analysis, the iterative contracts represent important legal innovation and can be categorized as a proactive law instrument that has...... the potential to create more business success. However, empirical research still needs to be done in order to confirm that these types of contracts are better at securing business success than traditional contract forms....

  19. The ITER in-vessel system

    Energy Technology Data Exchange (ETDEWEB)

    Lousteau, D.C.

    1994-09-01

    The overall programmatic objective, as defined in the ITER Engineering Design Activities (EDA) Agreement, is to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes. The ITER EDA Phase, due to last until July 1998, will encompass the design of the device and its auxiliary systems and facilities, including the preparation of engineering drawings. The EDA also incorporates validating research and development (R&D) work, including the development and testing of key components. The purpose of this paper is to review the status of the design, as it has been developed so far, emphasizing the design and integration of those components contained within the vacuum vessel of the ITER device. The components included in the in-vessel systems are divertor and first wall; blanket and shield; plasma heating, fueling, and vacuum pumping equipment; and remote handling equipment.

  20. Burning plasmas in ITER for energy source

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Nobuyuki [Atomic Energy Commission, Tokyo (Japan)

    2002-10-01

    Fusion research and development has two aspects. One is an academic research on science and technology, i.e., discovery and understanding of unexpected phenomena and, development of innovative technology, respectively. The other is energy source development to realize fusion as a viable energy future. Fusion research has been made remarkable progress in the past several decades, and ITER will soon realize burning plasma that is essential for both academic research and energy development. With ITER, scientific research on unknown phenomena such as self-organization of the plasma in burning state will become possible and it contributes to create a variety of academic outcome. Fusion researchers will have a responsibility to generate actual energy, and electricity generation immediately after the success of burning plasma control experiment in ITER is the next important step that has to be discussed seriously. (author)

  1. Re-starting an Arnoldi iteration

    Energy Technology Data Exchange (ETDEWEB)

    Lehoucq, R.B. [Argonne National Lab., IL (United States)

    1996-12-31

    The Arnoldi iteration is an efficient procedure for approximating a subset of the eigensystem of a large sparse n x n matrix A. The iteration produces a partial orthogonal reduction of A into an upper Hessenberg matrix H{sub m} of order m. The eigenvalues of this small matrix H{sub m} are used to approximate a subset of the eigenvalues of the large matrix A. The eigenvalues of H{sub m} improve as estimates to those of A as m increases. Unfortunately, so does the cost and storage of the reduction. The idea of re-starting the Arnoldi iteration is motivated by the prohibitive cost associated with building a large factorization.

  2. A Preliminary, Full Spectrum, Magnetic Anomaly Grid of the United States with Improved Long Wavelengths for Studying Continental Dynamics: A Website for Distribution of Data

    Science.gov (United States)

    Ravat, D.; Finn, C.; Hill, P.; Kucks, R.; Phillips, J.; Blakely, R.; Bouligand, C.; Sabaka, T.; Elshayat, A.; Aref, A.; Elawadi, E.

    2009-01-01

    Under an initiative started by Thomas G. Hildenbrand of the U.S. Geological Survey, we have improved the long-wavelength (50-2,500 km) content of the regional magnetic anomaly compilation for the conterminous United States by utilizing a nearly homogeneous set of National Uranium Resource Evaluation (NURE) magnetic surveys flown from 1975 to 1981. The surveys were flown in quadrangles of 2 deg of longitude by 1 deg of latitude with east-west flight lines spaced 4.8 to 9.6 km apart, north-south tie lines variably spaced, and a nominal terrain clearance of 122 m. Many of the surveys used base-station magnetometers to remove external field variations.

  3. Preliminary study on magnetic tracking-based planar shape sensing and navigation for flexible surgical robots in transoral surgery: methods and phantom experiments.

    Science.gov (United States)

    Song, Shuang; Zhang, Changchun; Liu, Li; Meng, Max Q-H

    2017-10-05

    Flexible surgical robot can work in confined and complex environments, which makes it a good option for minimally invasive surgery. In order to utilize flexible manipulators in complicated and constrained surgical environments, it is of great significance to monitor the position and shape of the curvilinear manipulator in real time during the procedures. In this paper, we propose a magnetic tracking-based planar shape sensing and navigation system for flexible surgical robots in the transoral surgery. The system can provide the real-time tip position and shape information of the robot during the operation. We use wire-driven flexible robot to serve as the manipulator. It has three degrees of freedom. A permanent magnet is mounted at the distal end of the robot. Its magnetic field can be sensed with a magnetic sensor array. Therefore, position and orientation of the tip can be estimated utilizing a tracking method. A shape sensing algorithm is then carried out to estimate the real-time shape based on the tip pose. With the tip pose and shape display in the 3D reconstructed CT model, navigation can be achieved. Using the proposed system, we carried out planar navigation experiments on a skull phantom to touch three different target positions under the navigation of the skull display interface. During the experiments, the real-time shape has been well monitored and distance errors between the robot tip and the targets in the skull have been recorded. The mean navigation error is [Formula: see text] mm, while the maximum error is 3.2 mm. The proposed method provides the advantages that no sensors are needed to mount on the robot and no line-of-sight problem. Experimental results verified the feasibility of the proposed method.

  4. Hydroflotation magnetic-aided endolumenal navigation-preliminary platform in ex-vivo setting for the next paradigm in minimally invasive urologic surgery.

    Science.gov (United States)

    Kommu, Sashi S

    2010-07-01

    Navigation of endolumenal devices, such as image rendering capsules, have been described for diagnostic purposes in the animal, and more recently, human models. In urology, the ureter is a prime lumenal structure that often needs to be explored for diagnostic and therapeutic purposes. A novel device using a flotation mechanism in a water-filled environment was developed and its navigation achieved with magnetic-aided guidance. The device was tested for propulsion and real-time control in the ex-vivo setting. An endolumenal bionic worm (EBW) with a magnetic core was developed and introduced into synthetic lumens (SL) and supermarket chicken lumenal structures. The latter involved the gastrointestinal lumenal tissue of supermarket chickens; ie, the ex-vivo equivalent of a ureteral substitute lumen (USL). Navigation was graded by achievement of the EBW in propulsion to premarked sites, ability to remain static when necessary, and trauma to the USL. The structures were observed under the microscope for breech after the exercises. Navigation was observed in 10 SLs and 10 USLs. The EBW was successfully steered using the magnetic guidance system with hydroflotation. Observation of endolumenal surfaces did not reveal evidence of trauma in either model. Hydroflotation magnetic-aided endolumenal navigation (HMAEN) of a microdevice was achieved endolumenally with targeted real-time control and with no observed trauma to the structures. HMAEN could potentially be used to guide devices like the EBW to permit diagnostic and therapeutic ureteroscopy including biopsy of ureteral and renal pelvis lesions, thus ushering in the platform for the next paradigm in endolumenal urologic procedures.

  5. The Efficacy and Utilisation of Preoperative Magnetic Resonance Imaging in Robot-assisted Radical Prostatectomy: Does it Change the Surgical Dissection Plan? A Preliminary Report

    OpenAIRE

    Hasan Hüseyin Tavukçu; Ömer Aytaç; Cem Balcı; Haluk Kulaksızoğıu; Fatih Atuğ

    2015-01-01

    Purpose: We investigated the effect of prostate magnetic resonance imaging (MRI) on the dissection plan of the neurovascular bundle and the oncological results of our patients who underwent robotic radical prostatectomy operation. Materials and Methods: We prospectively evaluated 30 consecutive patients, 15 of whom had prostate MRI before the operation, and 15 of whom did not. With the findings of MRI, the dissection plan was changed as intrafascial, interfascial, and extrafascial techniqu...

  6. Fusion neutron diagnostics on ITER tokamak

    Science.gov (United States)

    Bertalot, L.; Barnsley, R.; Direz, M. F.; Drevon, J. M.; Encheva, A.; Jakhar, S.; Kashchuk, Y.; Patel, K. M.; Arumugam, A. P.; Udintsev, V.; Walker, C.; Walsh, M.

    2012-04-01

    ITER is an experimental nuclear reactor, aiming to demonstrate the feasibility of nuclear fusion realization in order to use it as a new source of energy. ITER is a plasma device (tokamak type) which will be equipped with a set of plasma diagnostic tools to satisfy three key requirements: machine protection, plasma control and physics studies by measuring about 100 different parameters. ITER diagnostic equipment is integrated in several ports at upper, equatorial and divertor levels as well internally in many vacuum vessel locations. The Diagnostic Systems will be procured from ITER Members (Japan, Russia, India, United States, Japan, Korea and European Union) mainly with the supporting structures in the ports. The various diagnostics will be challenged by high nuclear radiation and electromagnetic fields as well by severe environmental conditions (ultra high vacuum, high thermal loads). Several neutron systems with different sensitivities are foreseen to measure ITER expected neutron emission from 1014 up to almost 1021 n/s. The measurement of total neutron emissivity is performed by means of Neutron Flux Monitors (NFM) installed in diagnostic ports and by Divertor Neutron Flux Monitors (DNFM) plus MicroFission Chambers (MFC) located inside the vacuum vessel. The neutron emission profile is measured with radial and vertical neutron cameras. Spectroscopy is accomplished with spectrometers looking particularly at 2.5 and 14 MeV neutron energy. Neutron Activation System (NAS), with irradiation ends inside the vacuum vessel, provide neutron yield data. A calibration strategy of the neutron diagnostics has been developed foreseeing in situ and cross calibration campaigns. An overview of ITER neutron diagnostic systems and of the associated challenging engineering and integration issues will be reported.

  7. Iterative quantum algorithm for distributed clock synchronization

    Institute of Scientific and Technical Information of China (English)

    Wang Hong-Fu; Zhang Shou

    2012-01-01

    Clock synchronization is a well-studied problem with many practical and scientific applications.We propose an arbitrary accuracy iterative quantum algorithm for distributed clock synchronization using only three qubits.The n bits of the time difference △ between two spatially separated clocks can be deterministically extracted by communicating only O(n) messages and executing the quantum iteration process n times based on the classical feedback and measurement operations.Finally,we also give the algorithm using only two qubits and discuss the success probability of the algorithm.

  8. Rational Verification in Iterated Electric Boolean Games

    Directory of Open Access Journals (Sweden)

    Youssouf Oualhadj

    2016-07-01

    Full Text Available Electric boolean games are compact representations of games where the players have qualitative objectives described by LTL formulae and have limited resources. We study the complexity of several decision problems related to the analysis of rationality in electric boolean games with LTL objectives. In particular, we report that the problem of deciding whether a profile is a Nash equilibrium in an iterated electric boolean game is no harder than in iterated boolean games without resource bounds. We show that it is a PSPACE-complete problem. As a corollary, we obtain that both rational elimination and rational construction of Nash equilibria by a supervising authority are PSPACE-complete problems.

  9. Iterated learning and the evolution of language.

    Science.gov (United States)

    Kirby, Simon; Griffiths, Tom; Smith, Kenny

    2014-10-01

    Iterated learning describes the process whereby an individual learns their behaviour by exposure to another individual's behaviour, who themselves learnt it in the same way. It can be seen as a key mechanism of cultural evolution. We review various methods for understanding how behaviour is shaped by the iterated learning process: computational agent-based simulations; mathematical modelling; and laboratory experiments in humans and non-human animals. We show how this framework has been used to explain the origins of structure in language, and argue that cultural evolution must be considered alongside biological evolution in explanations of language origins. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Accelerated iterative beam angle selection in IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Bangert, Mark, E-mail: m.bangert@dkfz.de [Department of Medical Physics in Radiation Oncology, German Cancer Research Center—DKFZ, Im Neuenheimer Feld 280, Heidelberg D-69120 (Germany); Unkelbach, Jan [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)

    2016-03-15

    Purpose: Iterative methods for beam angle selection (BAS) for intensity-modulated radiation therapy (IMRT) planning sequentially construct a beneficial ensemble of beam directions. In a naïve implementation, the nth beam is selected by adding beam orientations one-by-one from a discrete set of candidates to an existing ensemble of (n − 1) beams. The best beam orientation is identified in a time consuming process by solving the fluence map optimization (FMO) problem for every candidate beam and selecting the beam that yields the largest improvement to the objective function value. This paper evaluates two alternative methods to accelerate iterative BAS based on surrogates for the FMO objective function value. Methods: We suggest to select candidate beams not based on the FMO objective function value after convergence but (1) based on the objective function value after five FMO iterations of a gradient based algorithm and (2) based on a projected gradient of the FMO problem in the first iteration. The performance of the objective function surrogates is evaluated based on the resulting objective function values and dose statistics in a treatment planning study comprising three intracranial, three pancreas, and three prostate cases. Furthermore, iterative BAS is evaluated for an application in which a small number of noncoplanar beams complement a set of coplanar beam orientations. This scenario is of practical interest as noncoplanar setups may require additional attention of the treatment personnel for every couch rotation. Results: Iterative BAS relying on objective function surrogates yields similar results compared to naïve BAS with regard to the objective function values and dose statistics. At the same time, early stopping of the FMO and using the projected gradient during the first iteration enable reductions in computation time by approximately one to two orders of magnitude. With regard to the clinical delivery of noncoplanar IMRT treatments, we could

  11. Iterative solution of large linear systems

    CERN Document Server

    Young, David M

    2003-01-01

    This self-contained treatment offers a systematic development of the theory of iterative methods. Its focal point resides in an analysis of the convergence properties of the successive overrelaxation (SOR) method, as applied to a linear system with a consistently ordered matrix. The text explores the convergence properties of the SOR method and related techniques in terms of the spectral radii of the associated matrices as well as in terms of certain matrix norms. Contents include a review of matrix theory and general properties of iterative methods; SOR method and stationary modified SOR meth

  12. Precise fixpoint computation through strategy iteration

    DEFF Research Database (Denmark)

    Gawlitza, Thomas; Seidl, Helmut

    2007-01-01

    We present a practical algorithm for computing least solutions of systems of equations over the integers with addition, multiplication with positive constants, maximum and minimum. The algorithm is based on strategy iteration. Its run-time (w.r.t. the uniform cost measure) is independent of the s......We present a practical algorithm for computing least solutions of systems of equations over the integers with addition, multiplication with positive constants, maximum and minimum. The algorithm is based on strategy iteration. Its run-time (w.r.t. the uniform cost measure) is independent...

  13. Iterative Contracts as Proactive Law Instruments

    DEFF Research Database (Denmark)

    Henschel, René Franz

    2012-01-01

    and incremental software development. In contrast to traditional IT project methodologies, where the product development takes place in a sequential design process, the iterative process is characterized by the so_ ware being developed through a series of repeated cycles in smaller portions at a time....... This software development process has driven the need for a new contract design that supports the product life cycle better than the traditional contracts. As will be shown in the analysis, the iterative contracts represent important legal innovation and can be categorized as a proactive law instrument that has...

  14. Efficient iterative technique for designing bragg gratings

    DEFF Research Database (Denmark)

    Plougmann, Nikolai; Kristensen, Martin

    2004-01-01

    We present a new iterative method for designing Bragg gratings based on the Levenberg-Marquardt method of minimizing a chi-squared merit function. It is effective for designing both weak and strong gratings and is particularly well suited for unchirped gratings.......We present a new iterative method for designing Bragg gratings based on the Levenberg-Marquardt method of minimizing a chi-squared merit function. It is effective for designing both weak and strong gratings and is particularly well suited for unchirped gratings....

  15. Fatigue tests on the ITER PF jacket

    Science.gov (United States)

    Qin, Jinggang; Weiss, Klaus-Peter; Wu, Yu; Wu, Zhixiong; Li, Laifeng; Liu, Sheng

    2012-10-01

    This paper focuses on fatigue tests on the ITER Poloidal Field (PF) jacket made of 316L stainless steel material. During manufacture, the conductor will be compacted and spooled after cable insertion. Therefore, sample jackets were prepared under compaction, bending and straightening in order to simulate the status of PF conductor during manufacturing and winding. The fatigue properties of materials were measured at T fatigue crack growth rate (FCGR). The testing results show that the present Chinese PF jacket has good fatigue properties, which conclude that the results are accordant with the requirements of ITER.

  16. Overview of recent nuclear analyses for the Upper ECH launcher in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Serikov, A., E-mail: serikov@inr.fzk.d [Association FZK-EURATOM, Forschungszentrum Karlsruhe, P.O. Box 3640, D-76021 Karlsruhe (Germany); Fischer, U.; Grosse, D.; Heidinger, R.; Kleefeldt, K.; Spaeh, P.; Strauss, D.; Vaccaro, A. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, P.O. Box 3640, D-76021 Karlsruhe (Germany)

    2010-12-15

    An overview is given for the analyses of the nuclear physics characteristics in support of the development of the Electron Cyclotron Heating (ECH) launcher installed in the ITER upper port. The launcher's Quasi-Optical (QO) system of millimeter-wave guides represents a pathway for the neutron streaming which results in radiation loads on the launcher internals, mainly on the front steering (FS) mirrors and neighboring ITER components, in particular the vacuum vessel (VV) and the superconducting magnets surrounding the launcher. The radiation transport calculations were performed with the Monte Carlo code MCNP5 employing the recent MCNP geometry model of ITER called Alite and the FENDL-2.1 nuclear data. A dedicated CAD model of the QO ECH launcher, generated with CATIA V5, was converted at FZK into the MCNP5 geometry representation using the McCad conversion tool. The neutron and photon fluxes and critical nuclear responses, such as nuclear heating, neutron damage, and the helium production rate were calculated in the paper and compared with the ITER nuclear design limits. On the basis of the results obtained from the nuclear analyses, it is concluded that the recent design of the QO ECH launcher satisfies the ITER radiation requirements, and thus, from this point of view, can be operated safely.

  17. Development of the ITER Continuous External Rogowski: From conceptual design to final design

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, Philippe, E-mail: philippe.jacques.moreau@cea.fr [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Spuig, Pascal; Le-luyer, Alain; Malard, Philippe; Cantone, Bruno; Pastor, Patrick; Saint-Laurent, François [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Vayakis, George; Delhom, Dominique [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Arshad, Shakeib [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Lister, Jonathan; Toussaint, Matthieu; Marmillod, Philippe; Testa, Duccio; Schlatter, Christian [Ecole polytechnique fédérale de Lausanne, Centre de Recherches en Physique des Plasmas, 1015 Lausanne (Switzerland); Peruzzo, Simone [Consorzio RFX, C.so Stati Uniti 4, 35127 Padova (Italy)

    2015-10-15

    Highlights: • ITER Continuous External Rogowskis are designed for plasma current measurement. • CER are located in the casing of Toroidal Field Coils and will operate at 4.5 K. • The design of the sensors has been completed and validated through prototypes. • Detailed assembly procedure inside the toroidal field coil casing has been defined. • The CER has passed all the ITER and F4E design review procedures. - Abstract: In ITER, an accurate measurement of plasma current, with high reliability, is mandatory as this parameter is used to demonstrate licensing compliance with regulatory limits. For that purpose, several independent measurements based on magnetic diagnostics have been proposed. Rogowski coils are standard inductive sensors for current measurement in many applications. In ITER, three continuous external Rogowski coils are to be installed in the casing of the toroidal field coils. These sensors are remarkable from several points of view: overall length is about 40 m, high sensitivity needed, located in the toroidal field coil casing at 4.5 K and complex 3D routing with tight bending radius of 50 mm. Since 2005 an extensive work has been carried out to develop and analyze several design options complying with ITER specifications. Prototypes of a selected continuous external Rogowski design were built and tested successfully in terms of electrical, thermal, mechanical and vacuum characteristics. Finally a detailed assembly procedure inside the toroidal field coil casing has been defined according to the coil manufacturing and assembly constraints.

  18. Validation of the ITER CXRS design by tests on TEXTORa)

    Science.gov (United States)

    Jaspers, R. J. E.; von Hellermann, M. G.; Delabie, E.; Biel, W.; Marchuk, O.; Yao, L.

    2008-10-01

    The charge exchange recombination spectroscopy system (CXRS) for ITER is designed to measure the core helium concentration, and in addition, profiles of ion temperature and rotation. This highly demanding task, due to the huge background radiation (bremsstrahlung) and the high attenuation of the dedicated diagnostic neutral beam, requires high throughput spectrometers with high resolution. On TEXTOR, a CXRS system has been developed with the aim to test the physics implications of these specifications. (i) A relevant spectrometer has been tested. (ii) A method to determine the helium concentrations from the CXRS intensity, using the beam emission has been evaluated. A 20% discrepancy in beam emission was revealed. (iii) The determination of the magnetic pitch angle by the ratio of Balmer lines showed qualitatively the right behavior, although the accuracy was limited by the polarization sensitivity of the first mirror. (iv) The simulation code developed for the prediction of the CXRS spectra was quantitatively confronted with experimental data.

  19. Simulations of Alpha Wall Load in ITER. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Johan

    2010-10-20

    The partially DOE funded International Thermonuclear Experimental Reactor (ITER) will produce massive amounts of energetic charged alpha particles, which are imperfectly confined by a strong magnetic field. The wall of the experiment is designed to withstand an estimated wall load from these fusion alpha particles, but the accuracy of this estimate needs to be improved to avoid potentially catastrophic surprises when the experiment becomes operational. We have added a more accurate, gyro-dynamic model of particle motion to the existing drift-dynamic model in the DELTA5D simulation software used for the project. We have also added the ability to load a detailed engineering model of the wall and use it in the simulations.

  20. Modelling of radiation impact on ITER Beryllium wall

    Science.gov (United States)

    Landman, I. S.; Janeschitz, G.

    2009-04-01

    In the ITER H-Mode confinement regime, edge localized instabilities (ELMs) will perturb the discharge. Plasma lost after each ELM moves along magnetic field lines and impacts on divertor armour, causing plasma contamination by back propagating eroded carbon or tungsten. These impurities produce enhanced radiation flux distributed mainly over the beryllium main chamber wall. The simulation of the complicated processes involved are subject of the integrated tokamak code TOKES that is currently under development. This work describes the new TOKES model for radiation transport through confined plasma. Equations for level populations of the multi-fluid plasma species and the propagation of different kinds of radiation (resonance, recombination and bremsstrahlung photons) are implemented. First simulation results without account of resonance lines are presented.

  1. A path to stable low-torque plasma operation in ITER with test blanket modules

    Science.gov (United States)

    Lanctot, M. J.; Snipes, J. A.; Reimerdes, H.; Paz-Soldan, C.; Logan, N.; Hanson, J. M.; Buttery, R. J.; deGrassie, J. S.; Garofalo, A. M.; Gray, T. K.; Grierson, B. A.; King, J. D.; Kramer, G. J.; La Haye, R. J.; Pace, D. C.; Park, J.-K.; Salmi, A.; Shiraki, D.; Strait, E. J.; Solomon, W. M.; Tala, T.; Van Zeeland, M. A.

    2017-03-01

    New experiments in the low-torque ITER Q  =  10 scenario on DIII-D demonstrate that n  =  1 magnetic fields from a single row of ex-vessel control coils enable operation at ITER performance metrics in the presence of applied non-axisymmetric magnetic fields from a test blanket module (TBM) mock-up coil. With n  =  1 compensation, operation below the ITER-equivalent injected torque is successful at three times the ITER equivalent toroidal magnetic field ripple for a pair of TBMs in one equatorial port, whereas the uncompensated TBM field leads to rotation collapse, loss of H-mode and plasma current disruption. In companion experiments at high plasma beta, where the n  =  1 plasma response is enhanced, uncorrected TBM fields degrade energy confinement and the plasma angular momentum while increasing fast ion losses; however, disruptions are not routinely encountered owing to increased levels of injected neutral beam torque. In this regime, n  =  1 field compensation leads to recovery of a dominant fraction of the TBM-induced plasma pressure and rotation degradation, and an 80% reduction in the heat load to the first wall. These results show that the n  =  1 plasma response plays a dominant role in determining plasma stability, and that n  =  1 field compensation alone not only recovers most of the impact on plasma performance of the TBM, but also protects the first wall from potentially damaging heat flux. Despite these benefits, plasma rotation braking from the TBM fields cannot be fully recovered using standard error field control. Given the uncertainty in extrapolation of these results to the ITER configuration, it is prudent to design the TBMs with as low a ferromagnetic mass as possible without jeopardizing the TBM mission.

  2. Significance of ITER IWS Material Selection and Qualification

    Science.gov (United States)

    Mehta, Bhoomi K.; Raval, Jigar; Maheshwari, Abha; Laad, Rahul; Singh, Gurlovleen; Pathak, Haresh

    2017-04-01

    In-Wall Shielding (IWS) is one of the important components of ITER Vacuum Vessel (VV) which fills the space between double walls of VV with cooling water. Procurement Arrangement (PA) for IWS has been signed with Indian Domestic Agency (INDA). Procurement of IWS materials, fabrication of IWS blocks and its delivery to respective Domestic Agency (DA) and ITER Organization (IO) are the main scope of this PA. Hence, INDIA is the only country which is contributing to VV IWS among all seven ITER partners. The main functions of the IWS are to provide Neutron Shielding with blanket, VV shells and water during plasma operations and to reduce ripple of the Toroidal Magnetic Field. To meet these functional requirements IWS blocks are made up of special materials (Borated Steels SS304 B4 & SS304 B7, Ferritic Steels SS 430, Austenitic Steel SS 316 L (N)-IG, XM-19 and Inconel-625) which are qualified, reliable and traceable for the design assessment. The choice of these materials has a significant influence on performance, maintainability, licensing, detailed design parameters and waste disposal. The main reasons for the materials selected for IWS are its high mechanical strength at operating temperatures, water chemistry properties, excellent fabrication characteristics and low cost relative to other similar materials. All the materials are qualified with respect to their respective codes (ASTM/EN standards with additional requirements as described in RCC-MR code 2007) and ITER requirements. Agreed Notified Body (ANB) has control conformity of materials certificates with approved material specification and traceability procedure for Safety Important Component (SIC). The procurement strategy for all the IWS materials has been developed in close collaboration with IO, ANB and Industries as per Product Procurement Specification (PPS). The R&D for sample, bulk material production, testing, inspection and handling as required are carried out by IN DA and IO. At present almost all

  3. Differentiating laryngeal carcinomas from precursor lesions by diffusion-weighted magnetic resonance imaging at 3.0 T: a preliminary study.

    Directory of Open Access Journals (Sweden)

    De-Sheng Shang

    Full Text Available BACKGROUND: Diffusion-weighted magnetic resonance imaging (DWI has been introduced in head and neck cancers. Due to limitations in the performance of laryngeal DWI, including the complex anatomical structure of the larynx leading to susceptibility effects, the value of DWI in differentiating benign from malignant laryngeal lesions has largely been ignored. We assessed whether a threshold for the apparent diffusion coefficient (ADC was useful in differentiating preoperative laryngeal carcinomas from precursor lesions by turbo spin-echo (TSE DWI and 3.0-T magnetic resonance. METHODS: We evaluated DWI and the ADC value in 33 pathologically proven laryngeal carcinomas and 17 precancerous lesions. RESULTS: The sensitivity, specificity, and accuracy were 81.8%, 64.7%, 76.0% by laryngostroboscopy, respectively. The sensitivity, specificity, and accuracy of conventional magnetic resonance imaging were 90.9%, 76.5%, 86.0%, respectively. Qualitative DWI analysis produced sensitivity, specificity, and accuracy values of 100.0, 88.2, and 96.0%, respectively. The ADC values were lower for patients with laryngeal carcinoma (mean 1.195±0.32×10(-3 mm(2/s versus those with laryngeal precancerous lesions (mean 1.780±0.32×10(-3 mm(2/s; P<0.001. ROC analysis showed that the area under the curve was 0.956 and the optimum threshold for the ADC was 1.455×10(-3 mm(2/s, resulting in a sensitivity of 94.1%, a specificity of 90.9%, and an accuracy of 92.9%. CONCLUSIONS: Despite some limitations, including the small number of laryngeal carcinomas included, DWI may detect changes in tumor size and shape before they are visible by laryngostroboscopy. The ADC values were lower for patients with laryngeal carcinoma than for those with laryngeal precancerous lesions. The proposed cutoff for the ADC may help distinguish laryngeal carcinomas from laryngeal precancerous lesions.

  4. AN ITERATIVE EQUATION ON THE UNIT CIRCLE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A functional equation of nonlinear iterates is discussed on the circle S1 for its continuous solutions and differentiable solutions. By lifting to R, the existence, uniqueness and stability of those solutions are obtained. Techniques of continuation are used to guarantee the preservation of continuity and differentiability in lifting.

  5. Precise fixpoint computation through strategy iteration

    DEFF Research Database (Denmark)

    Gawlitza, Thomas; Seidl, Helmut

    2007-01-01

    We present a practical algorithm for computing least solutions of systems of equations over the integers with addition, multiplication with positive constants, maximum and minimum. The algorithm is based on strategy iteration. Its run-time (w.r.t. the uniform cost measure) is independent...

  6. Asymptotic iteration approach to supersymmetric bistable potentials

    Institute of Scientific and Technical Information of China (English)

    H. Ciftci; O. ozer; P. Roy

    2012-01-01

    We examine quasi exactly solvable bistable potentials and their supersymmetric partners within the framework of the asymptotic iteration method (AIM).It is shown that the AIM produces excellent approximate spectra and that sometimes it is found to be more useful to use the partner potential for computation. We also discuss the direct application of the AIM to the Fokker-Planck equation.

  7. Neutronic analysis for bolometers in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, A., E-mail: alejandro.suarez@iter.org [CIEMAT, Avda. Complutense 40, 28040 Madrid (Spain); Reichle, R.; Loughlin, M.; Polunovskiy, E.; Walsh, M. [ITER Organization, Route de Vinon sur Verdon, 13115, St. Paul lez Durance (France)

    2013-10-15

    Highlights: ► Radiation damage calculations for the bolometers in ITER. ► Redesign of the bolometric diagnostic in EPP01. ► New bolometer radiation damage values in EPP01 in the safe zone. -- Abstract: Neutronic considerations in ITER have such importance that they drive the design of many diagnostics and components of the machine, and bolometers are not an exception. Bolometer cameras will be installed on the vacuum vessel, viewing the plasma through the gaps between blanket modules, divertor, equatorial and upper port plugs. The ITER reference bolometer sensors are of a resistive type. For this study it is assumed that they are composed of a thin silicon nitride carrier film and platinum resistors disposed in a Wheatstone bridge configuration. Their assumed radiation hardness is 0.1 dpa. Neutronic calculations were performed with the Monte Carlo program MCNP5, the FENDL 2.1 nuclear data library and the latest B-lite ITER neutronic model with the appropriate modifications using the CAD to MCNP converter MCAM. A complete characterization of the neutron fluxes in all the bolometer locations and the calculation of neutron damage were performed. Values above the failure threshold damage were obtained for some of the bolometers, leading to a complete redesign of some parts of the bolometric system in order to extend its lifetime.

  8. Interpolation and Iteration for Nonlinear Filters

    CERN Document Server

    Chorin, Alexandre J

    2009-01-01

    We present a general form of the iteration and interpolation process used in implicit particle filters. Implicit filters are based on a pseudo-Gaussian representation of posterior densities, and are designed to focus the particle paths so as to reduce the number of particles needed in nonlinear data assimilation. Examples are given.

  9. Matched filter based iterative adaptive approach

    Science.gov (United States)

    Nepal, Ramesh; Zhang, Yan Rockee; Li, Zhengzheng; Blake, William

    2016-05-01

    Matched Filter sidelobes from diversified LPI waveform design and sensor resolution are two important considerations in radars and active sensors in general. Matched Filter sidelobes can potentially mask weaker targets, and low sensor resolution not only causes a high margin of error but also limits sensing in target-rich environment/ sector. The improvement in those factors, in part, concern with the transmitted waveform and consequently pulse compression techniques. An adaptive pulse compression algorithm is hence desired that can mitigate the aforementioned limitations. A new Matched Filter based Iterative Adaptive Approach, MF-IAA, as an extension to traditional Iterative Adaptive Approach, IAA, has been developed. MF-IAA takes its input as the Matched Filter output. The motivation here is to facilitate implementation of Iterative Adaptive Approach without disrupting the processing chain of traditional Matched Filter. Similar to IAA, MF-IAA is a user parameter free, iterative, weighted least square based spectral identification algorithm. This work focuses on the implementation of MF-IAA. The feasibility of MF-IAA is studied using a realistic airborne radar simulator as well as actual measured airborne radar data. The performance of MF-IAA is measured with different test waveforms, and different Signal-to-Noise (SNR) levels. In addition, Range-Doppler super-resolution using MF-IAA is investigated. Sidelobe reduction as well as super-resolution enhancement is validated. The robustness of MF-IAA with respect to different LPI waveforms and SNR levels is also demonstrated.

  10. Development of advanced inductive scenarios for ITER

    NARCIS (Netherlands)

    Luce, T. C.; Challis, C. D.; Ide, S.; Joffrin, E.; Kamada, Y.; Polizer, P. A.; Schweinzer, J.; Sips, A.C.C.; Stober, J.; Giruzzi, G.; Kessel, C. E.; Murakami, M.; Na, Y.-S.; Park, J. M.; Polevoi, A. R.; Budny, R. V.; Citrin, J.; Garcia, J.; Hayashi, N.; Hobirk, J.; Hudson, B. F.; Imbeaux, F.; Isayama, A.; McDonald, D. C.; Nakano, T.; Oyama, N.; Parail, V.V.; Petrie, T. W.; Petty, C. C.; Suzuki, T.; Wade, M. R.

    2014-01-01

    Since its inception in 2002, the International Tokamak Physics Activity topical group on Integrated Operational Scenarios (IOS) has coordinated experimental and modelling activity on the development of advanced inductive scenarios for applications in the ITER tokamak. The physics basis and the prosp

  11. Academic Training: The ITER project: technological challenges

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 31 May, 1, 2, 3, June from 11:00 to 12:00 on 31 May and 2, 3, June. From 10:00 to 12:00 on 1 June - Main Auditorium, bldg. 500 The ITER project: technological challenges J. LISTER / CRPP-EPFL, Lausanne, CH and P. BRUZZONE / CRPP-EPFL, Zürich, CH The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the...

  12. Academic Training: The ITER project: technological challenges

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 31 May, 1, 2, 3, June from 11:00 to 12:00 on 31 May and 2, 3, June. From 10:00 to 12:00 on 1 June - Main Auditorium, bldg. 500 The ITER project: technological challenges J. LISTER / CRPP-EPFL, Lausanne and P. BRUZZONE / CRPP-EPFL, Zürich The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the de...

  13. On iterative procedures of asymptotic inference

    NARCIS (Netherlands)

    K.O. Dzhaparidze (Kacha)

    1983-01-01

    textabstractAbstract  An informal discussion is given on performing an unconstrained maximization or solving non‐linear equations of statistics by iterative methods with the quadratic termination property. It is shown that if a miximized function, e.g. likelihood, is asymptotically quadratic, then f

  14. Iterative Reconstruction for Differential Phase Contrast Imaging

    NARCIS (Netherlands)

    Koehler, T.; Brendel, B.; Roessl, E.

    2011-01-01

    Purpose: The purpose of this work is to combine two areas of active research in tomographic x-ray imaging. The first one is the use of iterative reconstruction techniques. The second one is differential phase contrast imaging (DPCI). Method: We derive an SPS type maximum likelihood (ML) reconstructi

  15. Design and analysis of ITER shield blanket

    Energy Technology Data Exchange (ETDEWEB)

    Ohmori, Junji; Hatano, Toshihisa; Ezato, Kouichiro [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

    1998-12-01

    This report includes electromagnetic analyses for ITER shielding blanket modules, fabrication methods for the blanket modules and the back plate, the design and the fabrication methods for port limiter have been investigated. Studies on the runaway electron impact for Be armor have been also performed. (J.P.N.)

  16. Evaluating ITER remote handling middleware concepts

    NARCIS (Netherlands)

    Koning, J. F.; Heemskerk, C. J. M.; Schoen, P.; Smedinga, D.; Boode, A. H.; Hamilton, D. T.

    2013-01-01

    Remote maintenance activities in ITER will be performed by a unique set of hardware systems, supported by an extensive software kit. A layer of middleware will manage and control a complex set of interconnections between teams of operators, hardware devices in various operating theatres, and

  17. ITER faces further five-year delay

    Science.gov (United States)

    Clery, Daniel

    2016-06-01

    The €14bn ITER fusion reactor currently under construction in Cadarache, France, will require an additional cash injection of €4.6bn if it is to start up in 2025 - a target date that is already five years later than currently scheduled.

  18. Iterative solution of the Helmholtz equation

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, E.; Otto, K. [Uppsala Univ. (Sweden)

    1996-12-31

    We have shown that the numerical solution of the two-dimensional Helmholtz equation can be obtained in a very efficient way by using a preconditioned iterative method. We discretize the equation with second-order accurate finite difference operators and take special care to obtain non-reflecting boundary conditions. We solve the large, sparse system of equations that arises with the preconditioned restarted GMRES iteration. The preconditioner is of {open_quotes}fast Poisson type{close_quotes}, and is derived as a direct solver for a modified PDE problem.The arithmetic complexity for the preconditioner is O(n log{sub 2} n), where n is the number of grid points. As a test problem we use the propagation of sound waves in water in a duct with curved bottom. Numerical experiments show that the preconditioned iterative method is very efficient for this type of problem. The convergence rate does not decrease dramatically when the frequency increases. Compared to banded Gaussian elimination, which is a standard solution method for this type of problems, the iterative method shows significant gain in both storage requirement and arithmetic complexity. Furthermore, the relative gain increases when the frequency increases.

  19. Solving Differential Equations Using Modified Picard Iteration

    Science.gov (United States)

    Robin, W. A.

    2010-01-01

    Many classes of differential equations are shown to be open to solution through a method involving a combination of a direct integration approach with suitably modified Picard iterative procedures. The classes of differential equations considered include typical initial value, boundary value and eigenvalue problems arising in physics and…

  20. Wood anatomical classification using iterative character weighing

    NARCIS (Netherlands)

    Hogeweg, P.; Koek-Noorman, J.

    1975-01-01

    In this paper we investigate the pattern of wood anatomical variation in some groups of Rubiaceae (i.e. Cinchoneae, Rondeletieae and Condamineae) by using a numerical pattern detection method which involves character weighing (Hogeweg 1975). In this method character weights are obtained iteratively