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1

RAMI Analyses of Heating Neutral Beam and Diagnostic Neutral Beam Systems for ITER  

SciTech Connect

A RAMI (Reliability, Availability, Maintainability, Inspectability) analysis has been performed for the heating (and current drive) neutral beam (HNB) and diagnostic neutral beam (DNB) systems of the ITER device. The objective of these analyses is to implement RAMI engineering requirements for design and testing to prepare a reliability-centred plan for commissioning, operation, and maintenance of the system in the framework of technical risk control to support the overall ITER Project. These RAMI requirements will correspond to the RAMI targets for the ITER project and the compensating provisions to reach them as deduced from the necessary actions to decrease the risk level of the function failure modes. The RAMI analyses results have to match with the procurement plan of the systems.

Chang, D. H. [Korea Atomic Energy Research Institute(KAERI), Daejeon 305-353 (Korea, Republic of); Lee, S. [ITER-Korea Domestic Agency, National Fusion Research Institute(NFRI), Daejeon 305-333 (Korea, Republic of); Hemsworth, R.; Houtte, D. van; Okayama, K.; Sagot, F.; Schunke, B.; Svensson, L. [ITER Organization, 13067 St. Paul-lez-Durance Cedex (France)

2011-09-26

2

Design description and performance analyses of the European HCPB test blanket system in ITER feat  

Microsoft Academic Search

The helium cooled pebble bed (HCPB) blanket is one of the two European DEMO blanket concepts proposed for testing in international thermonuclear experimental reactor (ITER). The purpose of the tests is to validate the design principles and the operational feasibility for the demonstration blanket system. This includes the basic support functions like tritium extraction, helium cooling and heat transport, and

L. V Boccaccini; N Bekris; Y Chen; U Fischer; S Gordeev; S Hermsmeyer; E Hutter; K Kleefeldt; S Malang; K Schleisiek; I Schmuck; H Schnauder; H Tsige-Tamirat

2002-01-01

3

Development of the PACTITER code and its application to safety analyses of ITER Primary Cooling Water System  

Microsoft Academic Search

The PACTITER code derives from the PACTOLE code, developed by the CEA for predicting activated corrosion products (ACPs) in PWR primary circuits. The operating conditions, material compositions and water chemistry of the various Primary Heat Transfer Systems (PHTS) of the International Thermonuclear Experimental Reactor (ITER) made mandatory the adaptation of the PACTOLE code.PACTITER was developed on the basis of dedicated

L. Di Pace; F. Dacquait; P. Schindler; V. Blet; F. Nguyen; Y. Philibert; B. Larat

2007-01-01

4

Recurrent iterated function systems  

Microsoft Academic Search

Recurrent iterated function systems generalize iterated function systems as introduced by Barnsley and Demko [BD] in that a Markov chain (typically with some zeros in the transition probability matrix) is used to drive a system of mapswj:K ?K,j=1, 2,?,N, whereK is a complete metric space. It is proved that under “average contractivity,” a convergence and ergodic theorem obtains, which extends

Michael F. Barnsley; John H. Elton; Douglas P. Hardin

1989-01-01

5

SYSTEM STUDIES FOR ITER  

SciTech Connect

The following system studies were performed for the International Thermonuclear Experimental Reactor (ITER) using the Tokamak Engineering Test Reactor Analysis (TETRA) systems code: (1) a study of inductive vs current drive options for ITER, which addresses the cost trade-off of providing increased plasma burn capability inductively by increasing the bore of the ohmic heating (OH) solenoid (resulting in a tokamak with a larger major radius) as opposed to providing plasma current drive via rf or neutral beam injection (NBI); (2) an inboard shield trade study, which addresses the tradeoff of using tungsten or stainless steel shielding; and (3) a study of the impact of Confinement scaling on ITER parameters, which addresses the sensitivity of various proposed energy confinement time scaling algorithms on ITER ignition margin and cost.

Reid, R. L. [Oak Ridge National Laboratory (ORNL); Peng, Yueng Kay Martin [ORNL; Galambos, John D [ORNL

1989-01-01

6

The ITER vacuum systems  

NASA Astrophysics Data System (ADS)

ITER is a large vacuum facility which comprises many service, diagnostic and monitoring vacuum sub-systems as well as three large cryogenic pumping systems for evacuation and maintenance of the required pressure levels. Control of the gas throughput is one of the key issues affecting the performance and achievable burn time of a fusion reactor. The main pumping systems are the torus exhaust pumping, the cryopumps for the neutral beam injection systems for plasma heating, and the cryopumps for the ITER cryostat. All customized cryosorption pumps are force-cooled with supercritical helium and share a similar modular design of cryosorption pumping panels. For regeneration of the cryopumps as well as for roughing down the system volumes prior to operation, four identical sets of forepump trains are used. This paper will focus on the areas of the ITER vacuum systems which require customized developments and cannot rely on commercial solutions. The complex pumps have been tailored for the very specific applications and requirements at ITER, especially characterised by the need to be tritium compatible. An outline of the development path which was needed to come up with a sound design for the ITER cryopumps is given. The way of development is culminating in the manufacturing of 1:1 scale prototypes, which will be extensively tested in dedicated test facilities to ensure compatibility with all design requirements.

Day, C.; Murdoch, D.

2008-05-01

7

MELCOR 1.8.2 Analyses in Support of ITER’s RPrS  

SciTech Connect

The International Thermonuclear Experimental Reactor (ITER) Program is performing accident analyses for ITER’s “Rapport Préliminaire de Sûreté” (Report Preliminary on Safety - RPrS) with a modified version of the MELCOR 1.8.2 code. The RPrS is an ITER safety document required in the ITER licensing process to obtain a “Décret Autorisation de Construction” (a Decree Authorizing Construction - DAC) for the ITER device. This report documents the accident analyses performed by the US with the MELCOR 1.8.2 code in support of the ITER RPrS effort. This work was funded through an ITER Task Agreement for MELCOR Quality Assurance and Safety Analyses. Under this agreement, the US was tasked with performing analyses for three accident scenarios in the ITER facility. Contained within the text of this report are discussions that identify the cause of these accidents, descriptions of how these accidents are likely to proceed, the method used to analyze the consequences of these accidents, and discussions of the transient thermal hydraulic and radiological release results for these accidents.

Brad J Merrill

2008-01-01

8

ECRH System For ITER  

SciTech Connect

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

Darbos, C.; Henderson, M.; Gandini, F. [JTER Organization, 13067 Saint Paul-Lez-Durance cedex (France); Albajar, F.; Bomcelli, T.; Heidinger, R.; Saibene, G. [Fusion for Energy, C/Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona-Spain (Spain); Bigelow, T.; Rasmussen, D. [US ITER Project Office, Oak Ridge National Laboratory, 055 Commerce Park, PO Box 2008, Oak Ridge, TN 37831-6483 (United States); Chavan, R.; Goodman, T.; Hogge, J. P.; Sauter, O. [Association EURATOM-Confederation Suisse, EPFL Ecublens, CH-1015 Lausanne (Switzerland); Denisov, G. [Institute of Applied Physics Russian Academy of Sciences, 46 Ulyanov Street, Nizhny Novgorod, 603950 (Russian Federation); Farina, D. [Istitutodi Fisica del Plasma, Association EURATOM-ENEA-CNR, Milano (Italy); Kajiwara, K.; Kasugai, A.; Kobayashi, N.; Oda, Y.; Ramponi, G. [Japan Atomic Energy Agency (JAEA) 801-1 Mukoyama, Naka-shi, Ibaraki 311-0193 (Japan)] (and others)

2009-11-26

9

ITER Construction--Plant System Integration  

SciTech Connect

This brief paper introduces how the ITER will be built in the international collaboration. The ITER Organization plays a central role in constructing ITER and leading it into operation. Since most of the ITER components are to be provided in-kind from the member countries, integral project management should be scoped in advance of real work. Those include design, procurement, system assembly, testing, licensing and commissioning of ITER.

Tada, E. [ITER Organization Cadarache Center, 13108 St Paul lez Durance (France); Matsuda, S. [Japan Atomic Energy Research Agency, 100-0011, Chiyoda-ku, Tokyo (Japan)

2009-02-19

10

Remote handling systems for ITER  

Microsoft Academic Search

The requirement to reduce the investment cost for ITER as compared with the 1998 ITER design, has led to a reduction in the size of the ITER machine and a number of design changes which have an impact on the remote maintenance of ITER Major components to be considered for remote handling (RH) include the divertor cassettes, shield blanket modules,

T Honda; Y Hattori; C Holloway; E Martin; Y Matsumoto; T Matsunobu; T Suzuki; A Tesini; V Baulo; R Haange; J Palmer; K Shibanuma

2002-01-01

11

ETR/ITER systems code  

SciTech Connect

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.

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

12

Assessment of CONTAIN and MELCOR for performing LOCA and LOVA analyses in ITER  

Microsoft Academic Search

This report describes the results of an assessment of the CONTAIN and MELCOR computer codes for ITER LOCA and LOVA applications. As part of the assessment, the results of running a test problem that describes an ITER LOCA are presented. It is concluded that the MELCOR code should be the preferred code for ITER severe accident thermal hydraulic analyses. This

B. J. Merrill; D. L. Hagrman; M. J. Gaeta; D. A. Petti

1994-01-01

13

MELCOR 1.8.2 Analyses in Support of ITERs RPrS  

Microsoft Academic Search

The International Thermonuclear Experimental Reactor (ITER) Program is performing accident analyses for ITERs Rapport Préliminaire de Sûreté (Report Preliminary on Safety - RPrS) with a modified version of the MELCOR 1.8.2 code. The RPrS is an ITER safety document required in the ITER licensing process to obtain a Décret Autorisation de Construction (a Decree Authorizing Construction - DAC) for the

Brad J. Merrill

2008-01-01

14

ITER Ion Cyclotron Heating and Fueling Systems  

SciTech Connect

The ITER burning plasma and advanced operating regimes require robust and reliable heating and current drive and fueling systems. The ITER design documents describe the requirements and reference designs for the ion cyclotron and pellet fueling systems. Development and testing programs are required to optimize, validate and qualify these systems for installation on ITER.The ITER ion cyclotron system offers significant technology challenges. The antenna must operate in a nuclear environment and withstand heat loads and disruption forces beyond present-day designs. It must operate for long pulse lengths and be highly reliable, delivering power to a plasma load with properties that will change throughout the discharge. The ITER ion cyclotron system consists of one eight-strap antenna, eight rf sources (20 MW, 35-65 MHz), associated high-voltage DC power supplies, transmission lines and matching and decoupling components.The ITER fueling system consists of a gas injection system and multiple pellet injectors for edge fueling and deep core fueling. Pellet injection will be the primary ITER fuel delivery system. The fueling requirements will require significant extensions in pellet injector pulse length ({approx}3000 s), throughput (400 torr-L/s,) and reliability. The proposed design is based on a centrifuge accelerator fed by a continuous screw extruder. Inner wall pellet injection with the use of curved guide tubes will be utilized for deep fueling.

Rasmussen, D.A. [Oak Ridge National Laboratory (United States); Baylor, L.R. [Oak Ridge National Laboratory (United States); Combs, S.K. [Oak Ridge National Laboratory (United States); Fredd, E. [Princeton Plasma Physics Laboratory (United States); Goulding, R.H. [Oak Ridge National Laboratory (United States); Hosea, J. [Princeton Plasma Physics Laboratory (United States); Swain, D.W. [Oak Ridge National Laboratory (United States)

2005-04-15

15

Engineering design of the ITER RF systems.  

National Technical Information Service (NTIS)

Parallel conceptual design efforts for auxiliary heating systems on ITER are being carried out in both the electron cyclotron range of frequencies (ECRF) and ion cyclotron range of frequencies (ICRF). These systems are required to deliver a minimum of 50 ...

M. Makowski G. Bosia T. Nagashima D. Remsen

1994-01-01

16

Assessment of CONTAIN and MELCOR for performing LOCA and LOVA analyses in ITER  

SciTech Connect

This report describes the results of an assessment of the CONTAIN and MELCOR computer codes for ITER LOCA and LOVA applications. As part of the assessment, the results of running a test problem that describes an ITER LOCA are presented. It is concluded that the MELCOR code should be the preferred code for ITER severe accident thermal hydraulic analyses. This code will require the least modification to be appropriate for calculating thermal hydraulic behavior in ITER relevant conditions that include vacuum, cryogenics, ITER temperatures, and the presence of a liquid metal test module. The assessment of the aerosol transport models in these codes concludes that several modifications would have to be made to CONTAIN and/or MELCOR to make them applicable to the aerosol transport part of severe accident analysis in ITER.

Merrill, B.J.; Hagrman, D.L.; Gaeta, M.J.; Petti, D.A.

1994-09-01

17

Verification of MELCOR Input Decks Used in ITER RPrS Analyses  

SciTech Connect

This report as part of an ITER Task Agreement, documents the verification of the MELCOR Input Computer Decks used in performing the required safety analyses to be presented in the Preliminary Safety Report (Rapport Préliminaire de Séreté, RPrS).

Richard L. Moore

2008-01-01

18

Iterative design of video communication systems  

Microsoft Academic Search

This paper reviews the design and implementation of several video telephony systems at Bellcore as a case study in iterative design. In contrast to single user compuer applications, communication systems consists of both the interconnection technology and the people who are interconnected. From a user’s point of view, the capabilities provided by the system, the rules for its use, and

Colleen Cool; Robert S. Fish; Robert E. Kraut; C. M. Lowery

1992-01-01

19

Extending substructure based iterative solvers to multiple load and repeated analyses  

NASA Technical Reports Server (NTRS)

Direct solvers currently dominate commercial finite element structural software, but do not scale well in the fine granularity regime targeted by emerging parallel processors. Substructure based iterative solvers--often called also domain decomposition algorithms--lend themselves better to parallel processing, but must overcome several obstacles before earning their place in general purpose structural analysis programs. One such obstacle is the solution of systems with many or repeated right hand sides. Such systems arise, for example, in multiple load static analyses and in implicit linear dynamics computations. Direct solvers are well-suited for these problems because after the system matrix has been factored, the multiple or repeated solutions can be obtained through relatively inexpensive forward and backward substitutions. On the other hand, iterative solvers in general are ill-suited for these problems because they often must restart from scratch for every different right hand side. In this paper, we present a methodology for extending the range of applications of domain decomposition methods to problems with multiple or repeated right hand sides. Basically, we formulate the overall problem as a series of minimization problems over K-orthogonal and supplementary subspaces, and tailor the preconditioned conjugate gradient algorithm to solve them efficiently. The resulting solution method is scalable, whereas direct factorization schemes and forward and backward substitution algorithms are not. We illustrate the proposed methodology with the solution of static and dynamic structural problems, and highlight its potential to outperform forward and backward substitutions on parallel computers. As an example, we show that for a linear structural dynamics problem with 11640 degrees of freedom, every time-step beyond time-step 15 is solved in a single iteration and consumes 1.0 second on a 32 processor iPSC-860 system; for the same problem and the same parallel processor, a pair of forward/backward substitutions at each step consumes 15.0 seconds.

Farhat, Charbel

1993-01-01

20

The ITER Power And Particle Control System  

Microsoft Academic Search

The ITER power and particle control system is designed to exhaust the 300 to 400 MW of alpha and auxiliary heating power and the He ash created by the fusion reactions, to control the density, and to fuel the plasma. The power and particle control system consists of a single null poloidal divertor, a set of active pumps with a

D. Post; T. Ando; A. Antipenkov; S. Chiocchio; J. Dietz; G. Federici; M. Gouge; Y. Igitkhanov; G. Janeschitz; C. Karney; A. Kukushkin; P. Ladd; J. Mandrekas; E. Martin; D. Mitin; H. Nakamura; H. Pacher; R. Parker; W. Stacey; M. Sugihara; R. Tivey

1996-01-01

21

The ITER in-vessel system  

SciTech Connect

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.

Lousteau, D.C.

1994-09-01

22

Nuclear modules of ITER tokamak systems code  

SciTech Connect

Nuclear modules were developed to model various reactor components in the ITER systems code. Several design options and cost algorithms are included for each component. The first wall, blanket and shield modules calculate the beryllium zone thickness, the disruptions results, the nuclear responses in different components including the toroidal field coils. Tungsten shield/water coolant/steel structure and steel shield/water coolant are the shield options for the inboard and outboard sections of the reactor. Lithium nitrate dissolved in the water coolant with a variable beryllium zone thickness in the outboard section of the reactor provides the tritium breeding capability. The reactor vault module defines the thickness of the reactor wall and the roof based on the dose equivalent during operation including skyshine contribution. The impurity control module provides the design parameters for the divertor including plate design, heat load, erosion rate, tritium permeation through the plate material to the coolant, plasma contamination by sputtered impurities, and plate lifetime. Several materials: Be, C, V, Mo, and W can be used for the divertor plate to cover a range of plasma edge temperatures. The tritium module calculates tritium and deuterium flow rates for the reactor plant. The tritium inventory in the fuelers, neutral beams, vacuum pumps, impurity control, first wall, and blanket is calculated. Tritium requirements are provided for different operating conditions. The nuclear models are summarized in this paper including the different design options and key analyses of each module. 39 refs., 3 tabs.

Gohar, Y.; Baker, C.; Brooks, J.; Finn, P.; Hassanein, A.; Willms, S.; Barr, W.; Bushigin, A.; Kalyanam, K.M.; Haines, J.

1987-10-01

23

Engineering design of the ITER RF systems  

SciTech Connect

Parallel conceptual design efforts for auxiliary heating systems on ITER are being carried out in both the electron cyclotron range of frequencies (ECRF) and ion cyclotron range of frequencies (ICRF). These systems are required to deliver a minimum of 50 MW of CW power to the plasma for the primary purpose of heating and the secondary purpose of current drive. Current designs of the two systems are presented and the primary design issues are discussed.

Makowski, M. [Lawrence Livermore National Lab., CA (United States); Bosia, G. [European Commission, Garching, (Germany); Nagashima, T. [JAERI, Tokai-Mura, Ibaraki, (Japan); Remsen, D. [General Atomics, San Diego, CA (United States)

1994-12-31

24

ETR/ITER Systems Code.  

National Technical Information Service (NTIS)

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 s...

W. L. Barr C. G. Bathke J. N. Brooks R. H. Bulmer A. Busigin

1988-01-01

25

LSODKR. ODE System Solver W. Krylov Iteration & Rootfinding  

SciTech Connect

LSODKR is a new initial value ODE solver for stiff and nonstiff systems. It is a variant of the LSODPK and LSODE solvers, intended mainly for large stiff systems. The main differences between LSODKR and LSODE are the following: (a) for stiff systems, LSODKR uses a corrector iteration composed of Newton iteration and one of four preconditioned Krylov subspace iteration methods. The user must supply routines for the preconditioning operations, (b) Within the corrector iteration, LSODKR does automatic switching between functional (fixpoint) iteration and modified Newton iteration, (c) LSODKR includes the ability to find roots of given functions of the solution during the integration.

Hindmarsh, A.C.; Brown, P.N. [Lawrence Livermore National Lab., Numerical Mathematics Group, C.M.R.D., CA (United States)

1991-09-09

26

Neutronics and thermal design analyses of US solid breeder blanket for ITER  

SciTech Connect

The US Solid Breeder Blanket is designed to produce the necessary tritium required for the ITER operation and to operate at power reactor conditions as much as possible. Safety, low tritium inventory, reliability, flexibility cost, and minimum R D requirements are the other design criteria. To satisfy these criteria, the produced tritium is recovered continuously during operation and the blanket coolant operates at low pressure. Beryllium multiplier material is used to control the solid-breeder temperature. Neutronics and thermal design analyses were performed in an integrated manner to define the blanket configuration. The reference parameters of ITER including the operating scenarios, the neutron wall loading distribution and the copper stabilizer are included in the design analyses. Several analyses were performed to study the impact of the reactor parameters, blanket dimensions, material characteristics, and heat transfer coefficient at the material interfaces on the blanket performance. The design analyses and the results from the different studies are summarized. 6 refs., 3 figs., 3 tabs.

Gohar, Y.; Billone, M.; Attaya, H. (Argonne National Lab., IL (USA)); Sawan, M. (Wisconsin Univ., Madison, WI (USA))

1990-09-01

27

Fuzzy logic components for iterative deconvolution systems  

NASA Astrophysics Data System (ADS)

Deconvolution systems rely heavily on expert knowledge and would benefit from approaches that capture this expert knowledge. Fuzzy logic is an approach that is used to capture expert knowledge rules and produce outputs that range in degree. This paper describes a fuzzy-deconvolution-system that integrates traditional Richardson-Lucy deconvolution with fuzzy components. The system is intended for restoration of 3D widefield images taken under conditions of refractive index mismatch. The system uses a fuzzy rule set for calculating sample refractive index, a fuzzy median filter for inter-iteration noise reduction, and a fuzzy rule set for stopping criteria.

Northan, Brian M.

2013-02-01

28

Status of ITER ICH Matching System Design  

SciTech Connect

Work on the design of the ITER ICH matching system is progressing. The design has been significantly improved. The system will deliver a total power of 20 MW for long-pulse (>3000 s) operation. The present matching system has hybrid combiner-splitter circuits for ELM resilience, active matching during a shot using a double-stub-tuner circuit, decouplers between the eight inputs to each antenna, water-cooled transmission lines and matching components in the unmatched section, and air-cooled transmission lines using turbulent cooling.

Swain, D.; Goulding, R.; Rasmussen, D. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6483 (United States)

2009-11-26

29

Status of ITER ICH Matching System Design  

NASA Astrophysics Data System (ADS)

Work on the design of the ITER ICH matching system is progressing. The design has been significantly improved. The system will deliver a total power of 20 MW for long-pulse (>3000 s) operation. The present matching system has hybrid combiner-splitter circuits for ELM resilience, active matching during a shot using a double-stub-tuner circuit, decouplers between the eight inputs to each antenna, water-cooled transmission lines and matching components in the unmatched section, and air-cooled transmission lines using turbulent cooling.

Swain, D.; Goulding, R.; Rasmussen, D.

2009-11-01

30

Analyses of high power negative ion accelerators for ITER neutral beam injector (invited)  

SciTech Connect

In JAEA, research and developments to realize high power accelerator (1 MeV, 40 AD{sup -} ion beams for 3600 s) for ITER have been carried out experimentally and numerically utilizing a five stage MAMuG (Multiaperture, Multigrid) accelerator. In this paper, the extension of the gap length, which is required to improve the voltage holding capability, is examined in two dimensional beam optics analyses and also from view point of stripping loss of ions. In order to suppress excess power loadings due to the direct interception of negative ions, which is issued in long pulse tests, the beamlet deflection is analyzed in three dimensional multibeamlet analyses. The necessary modifications shown above are applied to the MAMuG accelerator for coming long pulse tests in JAEA and ITER.

Kashiwagi, M.; Taniguchi, M.; Dairaku, M.; Hanada, M.; Mizuno, T.; Tobari, H.; Umeda, N.; Watanabe, K.; Sakamoto, K.; Inoue, T. [Japan Atomic Energy Agency (JAEA), 801-1, Mukoyama, Naka 311-0193 (Japan); Grisham, L. R. [Princeton University, Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

2010-02-15

31

The ITER Radial Neutron Camera Detection System  

SciTech Connect

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 n{sub t}/n{sub d} 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 10{sup 8}-10{sup 9} n/cm{sup 2} 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.

Marocco, D.; Belli, F.; Esposito, B.; Petrizzi, L.; Riva, M. [Associazione ENEA-Euratom sulla Fusione, C.R. Frascati, C.P. 65, I-00044 Frascati (Roma) (Italy); Bonheure, G. [Laboratory for Plasma Physics, Association 'Euratom-Belgian State', Royal Military Academy, Avenue dela Renaissance, 30, B-1000 Brussels (Belgium); Kaschuck, Y. [TRINITI, Troitsk 142190, Moscow Region (Russian Federation)

2008-03-12

32

Status of ITER ICH Matching System Design  

NASA Astrophysics Data System (ADS)

Work on the design of the ITER ICH matching system is progressing. The system will deliver a total power of 20 MW for long-pulse (> 3000 s) operation. The present matching system design has: hybrid combiner-splitter circuits for ELM resilience, active matching during a shot using a double-stub tuner circuit, decouplers between the eight inputs to each antenna, water-cooled matching components, and air-cooled matched transmission lines using turbulent cooling. The matching/decoupling system is evolving. While the main components are fairly well determined, the configuration of the decoupler connections and tuning of the decouplers is still under discussion. More detailed specifications and predicted performance of the rf system under different plasma conditions will be presented.

Swain, D.; Goulding, R.; Rasmussen, D.

2009-11-01

33

Activation analyses for the different options considered in the US ITER blanket trade-off study  

Microsoft Academic Search

Detailed activation analyses were performed for the different blanket design options considered in the ITER blanket option trade-off study. The options considered included a self-cooled Li\\/V option, a helium-cooled Li\\/V option and a water-cooled 316 SS non-breeding shield option. A vacuum vessel made of double-wall Inconel 625 and water-cooled 316 SS balls was used with all options. The He-cooled blanket

Hesham Y Khater

1995-01-01

34

Design considerations for ITER (International Thermonuclear Experimental Reactor) magnet systems  

SciTech Connect

The International Thermonuclear Experimental Reactor (ITER) is now completing a definition phase as a beginning of a three-year design effort. Preliminary parameters for the superconducting magnet system have been established to guide further and more detailed design work. Radiation tolerance of the superconductors and insulators has been of prime importance, since it sets requirements for the neutron-shield dimension and sensitively influences reactor size. The major levels of mechanical stress in the structure appear in the cases of the inboard legs of the toroidal-field (TF) coils. The cases of the poloidal-field (PF) coils must be made thin or segmented to minimize eddy current heating during inductive plasma operation. As a result, the winding packs of both the TF and PF coils includes significant fractions of steel. The TF winding pack provides support against in-plane separating loads but offers little support against out-of-plane loads, unless shear-bonding of the conductors can be maintained. The removal of heat due to nuclear and ac loads has not been a fundamental limit to design, but certainly has non-negligible economic consequences. We present here preliminary ITER magnetic systems design parameters taken from trade studies, designs, and analyses performed by the Home Teams of the four ITER participants, by the ITER Magnet Design Unit in Garching, and by other participants at workshops organized by the Magnet Design Unit. The work presented here reflects the efforts of many, but the responsibility for the opinions expressed is the authors'. 4 refs., 3 figs., 4 tabs.

Henning, C.D.; Miller, J.R.

1988-10-09

35

Gas species, their evolution and segregation through the ITER vacuum systems  

SciTech Connect

This paper takes the ITER fueling requirements and current knowledge of gas balance and exhaust from operating tokamaks to predict all likely gas inputs into the ITER Vacuum systems. Areas where gas dynamics modeling is relevant to the ITER design are highlighted. The design and operation of the ITER vacuum system gives an element of segregation of different gas flows and species. This paper analyses the time dependent gas segregation in the vacuum system resulting from different temperature dependences of cryogenic sorption and condensation processes of different gas species. As a specific example, the optimal transfer of Ar-41 through the vacuum system is studied with respect to its decay and the resulting effects on the design of system components.

Pearce, R.J.H. [ITER Organization, Cadarache, France; Antipenkov, Alexander [ITER Joint Work Site, Cadarache; Bersier, Jean-Louis [ITER Joint Work Site, Cadarache; Boussier, Bastien [ITER Joint Work Site, Cadarache; Baylor, Larry R [ORNL; Gardner, Walter L [ORNL; Meitner, Steven J [ORNL

2012-01-01

36

Challenges for the ITER ion cyclotron system.  

National Technical Information Service (NTIS)

Ion cyclotron heating is one of the methods proposed for heating and for driving current in the ITER plasma. The ITER environment is significantly different from that of present day tokamak because of heating from neutrons and from the high radiated heat ...

D. W. Swain P. M. Ryan D. J. Taylor G. Bosia

1997-01-01

37

The upgraded laser in vessel viewing system (IVVS) for ITER  

Microsoft Academic Search

A prototype of a laser in vessel viewing and ranging system was developed at ENEA laboratories in Frascati, it uses the amplitude modulated laser radar concept and it is conceived to withstand the severe ITER conditions. The in vessel viewing system (IVVS) probe has been designed and built to perform sub-millimetric three-dimensional images inside ITER; it is based on an

C. Neri; A. Coletti; M. Ferri de Collibus; G. Fornetti; F. Pollastrone

2009-01-01

38

ITER  

SciTech Connect

This year six international partners have signed up to construct the first burning plasma experiment -- ITER -- in the South of France.It is over 50 years since the beginning of national programs to produce controlled fusion energy. The challenge of fusion energy has proven harder than was first anticipated. In this Colloquium Steve Cowley from UCLA will explain the scientific issues and how the difficulties have been overcome.

Steve Cowley

2005-10-10

39

Convergence Results on Iteration Algorithms to Linear Systems  

PubMed Central

In order to solve the large scale linear systems, backward and Jacobi iteration algorithms are employed. The convergence is the most important issue. In this paper, a unified backward iterative matrix is proposed. It shows that some well-known iterative algorithms can be deduced with it. The most important result is that the convergence results have been proved. Firstly, the spectral radius of the Jacobi iterative matrix is positive and the one of backward iterative matrix is strongly positive (lager than a positive constant). Secondly, the mentioned two iterations have the same convergence results (convergence or divergence simultaneously). Finally, some numerical experiments show that the proposed algorithms are correct and have the merit of backward methods.

Wang, Zhuande; Yang, Chuansheng; Yuan, Yubo

2014-01-01

40

Nonlinear dynamics of iterative decoding systems: analysis and applications  

Microsoft Academic Search

óIterative decoding algorithms may be viewed as high- dimensional nonlinear dynamical systems, depending on a large number of parameters. In this work, we introduce a simplied description of several iterative decoding algorithms in terms of the a posteriori average entropy, and study them as a function of a single parameter that closely approximates the signal-to- noise ratio (SNR). Using this

Ljupco Kocarev; Frédéric Lehmann; Gian Mario Maggio; Bartolo Scanavino; Zarko Tasev; Alexander Vardy

2006-01-01

41

Iterative receiver concept for TDMA packet data systems  

Microsoft Academic Search

In this paper we present an iterative receiver concept that improves the radio link performance of TDMA mobile communication systems. We consider sub-optimal receiver structures comprised of channel estimator, detector and channel decoder, where the performance is improved by iterative data processing among the receiver blocks. As a practical example we consider packet data transmission in GSM and EDGE (Enhanced

Nikolai Nefedov; Markku Pukkila; Raphaël Visoz; Antoine O. Berthet

2003-01-01

42

Verication of Detailed Iterative Static Schedules for Multiprocessor Systems  

Microsoft Academic Search

This paper considers the scheduling of homogeneous synchronous data-flow graphs also called iterative data-flow graphs (IDFGs) on a mul- tiprocessor system. Algorithms described by such graphs consist of a core computation that is iter- ated \\\\innitely often\\

P. W. G. Poiesz; Sabih H. Gere; Erwin R. Bonsma

43

Gas analyses of the first complete JET cryopump regeneration with ITER-like wall  

NASA Astrophysics Data System (ADS)

Analytical results of a complete JET cryopump regeneration, including the nitrogen panel, following the first ITER-like wall campaign are presented along with the in situ analyses of residual gas. H/D mixtures and impurities such as nitrogen and neon were injected during plasma operation in the vessel to study radiation cooling in the scrape-off-layer and divertor region. The global gas inventory over the campaign is incomplete, suggesting residual volatile impurities are remaining on the cryogenic panel. This paper presents results on (i) residual deuterium on the panel which is very loosely related to the campaign, (ii) impurities like nitrogen which stick on the panel, and (iii) the ammonia production which can be observed by mass spectrometry.

Grünhagen Romanelli, S.; Brezinsek, S.; Butler, B.; Coad, J. P.; Drenik, A.; Giroud, C.; Jachmich, S.; Keenan, T.; Kruezi, U.; Mozetic, M.; Oberkofler, M.; Parracho, A.; Romanelli, M.; Smith, R.; Yorkshades, J.; Contributors, JET-EFDA

2014-04-01

44

An iterative method for indefinite systems of linear equations  

NASA Technical Reports Server (NTRS)

An iterative method for solving nonsymmetric indefinite linear systems is proposed. The method involves the successive use of a modified version of the conjugate residual method. A numerical example is given to illustrate the method.

Ito, K.

1984-01-01

45

Neutronic analysis of iter cryopump system  

Microsoft Academic Search

The ITER Vacuum Vessel has upper, equatorial and lower port structures. The bottom ports are dedicated to the divertor replacement (five ports) and to vacuum pumping by means of cryopumps (four ports). The latest cryopump port design is more complex as it has a pump with a direct view of the vessel (upper cryopump) and a second pump at the

L. Petrizzi; M. Loughlin; A. Martin; F. Moro; R. Villari; M. Merola; R. Pearce

2009-01-01

46

Performance and capacity analysis of Poisson photon-counting based Iter-PIC OCDMA systems.  

PubMed

In this paper, an iterative parallel interference cancellation (Iter-PIC) technique is developed for optical code-division multiple-access (OCDMA) systems relying on shot-noise limited Poisson photon-counting reception. The novel semi-analytical tool of extrinsic information transfer (EXIT) charts is used for analysing both the bit error rate (BER) performance as well as the channel capacity of these systems and the results are verified by Monte Carlo simulations. The proposed Iter-PIC OCDMA system is capable of achieving two orders of magnitude BER improvements and a 0.1 nats of capacity improvement over the conventional chip-level OCDMA systems at a coding rate of 1/10. PMID:24216821

Li, Lingbin; Zhou, Xiaolin; Zhang, Rong; Zhang, Dingchen; Hanzo, Lajos

2013-11-01

47

An iterative method for systems of nonlinear hyperbolic equations  

NASA Technical Reports Server (NTRS)

An iterative algorithm for the efficient solution of systems of nonlinear hyperbolic equations is presented. Parallelism is evident at several levels. In the formation of the iteration, the equations are decoupled, thereby providing large grain parallelism. Parallelism may also be exploited within the solves for each equation. Convergence of the interation is established via a bounding function argument. Experimental results in two-dimensions are presented.

Scroggs, Jeffrey S.

1989-01-01

48

Iterative Soft QRD-M Decoding of Coded IFDMA Systems  

Microsoft Academic Search

We introduce an iterative decoding algorithm for the decoding of coded interleaved frequency division multiple access (IFDMA) system in this paper. The iterative decoding algorithm incorporates a low complexity a posterior probability (APP) detector based on breadth-first tree search algorithm with a soft-input soft-out (SISO) error-correcting codes (ECC) decoder. The proposed detector combines the principles of the M-algorithm with QR

Khiam-Boon Png; Xiaoming Peng; Francois P. S. Chin; Chi Chung Ko

2010-01-01

49

An Iterative Jackknife Approach for Assessing Reliability and Power of fMRI Group Analyses  

PubMed Central

For functional magnetic resonance imaging (fMRI) group activation maps, so-called second-level random effect approaches are commonly used, which are intended to be generalizable to the population as a whole. However, reliability of a certain activation focus as a function of group composition or group size cannot directly be deduced from such maps. This question is of particular relevance when examining smaller groups (<20–27 subjects). The approach presented here tries to address this issue by iteratively excluding each subject from a group study and presenting the overlap of the resulting (reduced) second-level maps in a group percent overlap map. This allows to judge where activation is reliable even upon excluding one, two, or three (or more) subjects, thereby also demonstrating the inherent variability that is still present in second-level analyses. Moreover, when progressively decreasing group size, foci of activation will become smaller and/or disappear; hence, the group size at which a given activation disappears can be considered to reflect the power necessary to detect this particular activation. Systematically exploiting this effect allows to rank clusters according to their observable effect size. The approach is tested using different scenarios from a recent fMRI study (children performing a “dual-use” fMRI task, n?=?39), and the implications of this approach are discussed.

Wilke, Marko

2012-01-01

50

Transportation systems analyses, volume 2  

NASA Astrophysics Data System (ADS)

The principal objective is to accomplish a systems engineering assessment of the nation's space transportation infrastructure. This analysis addresses the necessary elements to perform man delivery and return, cargo transfer, cargo delivery, payload servicing, and the exploration of the Moon and Mars. Specific elements analyzed, but not limited to, include the Space Exploration Initiative (SEI), the National Launch System (NLS), the current expendable launch vehicle (ELV) fleet, ground facilities, the Space Station Freedom (SSF), and other civil, military, and commercial payloads. The performance entails maintaining a broad perspective on the large number of transportation elements that could potentially comprise the U.S. space infrastructure over the next several decades. To perform this systems evaluation, top-level trade studies are conducted to enhance our understanding of the relationships between elements of the infrastructure. This broad 'infrastructure-level perspective' permits the identification of preferred infrastructures. Sensitivity analyses are performed to assure the credibility and usefulness of study results. Conceptual studies of transportation elements contribute to the systems approach by identifying elements (such as ETO node and transfer/excursion vehicles) needed in current and planned transportation systems. These studies are also a mechanism to integrate the results of relevant parallel studies.

1992-11-01

51

Network analyses in systems pharmacology  

PubMed Central

Systems pharmacology is an emerging area of pharmacology which utilizes network analysis of drug action as one of its approaches. By considering drug actions and side effects in the context of the regulatory networks within which the drug targets and disease gene products function, network analysis promises to greatly increase our knowledge of the mechanisms underlying the multiple actions of drugs. Systems pharmacology can provide new approaches for drug discovery for complex diseases. The integrated approach used in systems pharmacology can allow for drug action to be considered in the context of the whole genome. Network-based studies are becoming an increasingly important tool in understanding the relationships between drug action and disease susceptibility genes. This review discusses how analysis of biological networks has contributed to the genesis of systems pharmacology and how these studies have improved global understanding of drug targets, suggested new targets and approaches for therapeutics, and provided a deeper understanding of the effects of drugs. Taken together, these types of analyses can lead to new therapeutic options while improving the safety and efficacy of existing medications. Contact: ravi.iyengar@mssm.edu

Berger, Seth I.; Iyengar, Ravi

2009-01-01

52

Complex stochastic systems modelling and control via iterative machine learning  

Microsoft Academic Search

Complex stochastic systems require the control of their stochastic distributions (i.e., the shape of their output probability density functions (PDFs)). This paper will address both modelling and control of such systems and will consist of a brief survey of the recent developments and the description of a detailed design procedure on an iterative learning-based output PDF control algorithm. In this

Aiping Wang; Puya Afshar; Hong Wang

2008-01-01

53

Iterative learning control synthesis based on 2-D system theory  

Microsoft Academic Search

An algorithm is presented for iterative learning of the control input for a linear discrete-time multivariable system. Necessary and sufficient conditions are stated for convergence of the proposed algorithm. The algorithm synthesis and analysis are based on two-dimensional (2-D) system theory. A numerical example is given

J. E. Kurek; M. B. Zaremba

1993-01-01

54

Design of fast tuning elements for the ITER ICH system  

SciTech Connect

The coupling between the ion cyclotron (IC) antenna and the ITER plasma (as expressed by the load resistance the antenna sees) will experience relatively fast variations due to plasma edge profile modifications. If uncompensated, these will cause an increase in the amount of power reflected back to the transmitter and ultimately a decrease in the amount of radio frequency (rf) power to the plasma caused by protective suppression of the amount of rf power generated by the transmitter. The goals of this task were to study several alternate designs for a tuning and matching (T&M) system and to recommend some research and development (R&D) tasks that could be carried out to test some of the most promising concepts. Analyses of five different T&M configurations are presented in this report. They each have different advantages and disadvantages, and the choice among them must be made depending on the requirements for the IC system. Several general conclusions emerge from our study: The use of a hybrid splitter as a passive reflected-power dump [``edge localized mode (ELM)-dump``] appears very promising; this configuration will protect the rf power sources from reflected power during changes in plasma loading due to plasma motion or profile changes (e.g., ELM- induced changes in the plasma scrape-off region) and requires no active control of the rf system. Trade-offs between simplicity of design and capability of the system must be made. Simple system designs with few components near the antenna either have high voltages over considerable distances of transmission lines, or they are not easily tuned to operate at different frequencies. Designs using frequency shifts and/or fast tuning elements can provide fast matching over a wide range of plasma loading; however, the designs studied here require components near the antenna, complicating assembly and maintenance. Capacitor-tuned resonant systems may offer a good compromise.

Swain, D.W.; Goulding, R.H.

1996-05-01

55

Status of the ITER ICRF system design - 'Externally Matched' approach  

SciTech Connect

The design of the ITER ICRF system has been under revision for several years. The paper presents the status of the design proposal based on a 24 strap antenna plug (6 poloidal by 4 toroidal short radiating conductors) in which the straps are passively combined in 8 poloidal triplets by means of 4-port junctions. These triplets are connected in parallel pairwise through matching elements to form 4 load-resilient conjugate-T circuits. All adjustable matching elements are located outside the plug, i.e. in the ITER port cell and in the generator area.

Lamalle, P. U.; Dumortier, P.; Durodie, F.; Evrard, M.; Louche, F.; Messiaen, A.; Vervier, M. [Laboratory for Plasma Physics, Association EURATOM-Belgian State, Royal Military Academy, B-1000 Brussels (Belgium); Shannon, M.; Borthwick, A.; Chuilon, B.; Nightingale, M. [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Brons, S. [FOM IPP Rijnhuizen, Association EURATOM-FOM, The Netherlands (Netherlands); Goulding, R.; Swain, D. [Oak Ridge National Laboratory, TN 37831-6169, Tennessee, USA. Partners in TEC (United States)

2007-09-28

56

A first characterization of the quench detection system for ITER  

NASA Astrophysics Data System (ADS)

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

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

1995-03-01

57

The Iterating Artifact as a Fundamental Construct in Information System Design  

Microsoft Academic Search

Iterative development is fundamental principle of information system design methodologies. Yet, the idea of iteration remains poorly defined across literature streams. In this essay we identify the types of iterations that can occur in software development processes, and organize them into typologies by the iterating artifacts they generate. We then see how a sample of development approaches discuss these artifacts

Nicholas Berente; Kalle Lyytinen

58

Radiation effects on insulating gases for the ITER NBI system  

Microsoft Academic Search

The radiation induced leakage current in dry air and SF6 has been measured as a function of dose rate, voltage, and electrode separation in order to assess the problem for the ITER NBI system insulating gas. The results indicate that for the high voltages involved, the leakage current is a function of the gas volume rather than the electrode separation.

E. R. Hodgson; A. Moroño

1998-01-01

59

Arc detection for the ICRF system on ITER  

NASA Astrophysics Data System (ADS)

The ICRF system for ITER is designed to respect the high voltage breakdown limits. However arcs can still statistically happen and must be quickly detected and suppressed by shutting the RF power down. For the conception of a reliable and efficient detector, the analysis of the mechanism of arcs is necessary to find their unique signature. Numerous systems have been conceived to address the issues of arc detection. VSWR-based detectors, RF noise detectors, sound detectors, optical detectors, S-matrix based detectors. Until now, none of them has succeeded in demonstrating the fulfillment of all requirements and the studies for ITER now follow three directions: improvement of the existing concepts to fix their flaws, development of new theoretically fully compliant detectors (like the GUIDAR) and combination of several detectors to benefit from the advantages of each of them. Together with the physical and engineering challenges, the development of an arc detection system for ITER raises methodological concerns to extrapolate the results from basic experiments and present machines to the ITER scale ICRF system and to conduct a relevant risk analysis.

D'Inca, R.

2011-12-01

60

Design options for an ITER ion cyclotron system.  

National Technical Information Service (NTIS)

Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-sepa...

D. W. Swain F. W. Baity T. S. Bigelow P. M. Ryan R. H. Goulding

1995-01-01

61

ITER ICH Transmission Line and Matching System Progress*  

NASA Astrophysics Data System (ADS)

The ITER Ion Cyclotron Heating (ICH) system is required to deliver 20 MW to the ITER plasma for pulse lengths over 3000 s. The US is responsible for the design and fabrication of the transmission lines and matching system. Significant progress has been made in the design and layout of the system in the past year. The conceptual design has been done by the US and approved by the ITER International Organization (IO), and preliminary design has started. More detailed layouts and analysis of the matching system have been done. A new, more detailed matching system design that uses a 3-dB hybrid coupler and two shorting stubs in a phase-shifter mode is being analyzed. In collaboration with the IO, the layout of the transmission lines and matching system has been detailed. In addition, work has started on control algorithms to do real-time matching and control of the system in response to changing plasma conditions. An R&D program to test prototype concepts and components has been started; recent results and R&D plans will be presented. *The submitted manuscript has been authored by a contractor of the U.S. Government under contract DE-AC05-00OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes.

Swain, D.; Goulding, R.; Rasmussen, D.

2010-11-01

62

Process Flow and Functional Analysis of the Iter Cryogenic System  

Microsoft Academic Search

The ITER cryogenic system is presently under design by a large international collaboration. It will start commissioning at Cadarache, south of France in 2015. The system is designed to provide an equivalent refrigeration capacity of 65 kW at 4.5 K for the superconducting magnet and 1300 kW at 80 K for the cryoplant pre-cooling stages and the Cryostat Thermal Shields

D. Henry; M. Chalifour; A. Forgeas; V. Kalinin; E. Monneret; L. Serio; G. Vincent; T. Voigt

2010-01-01

63

Iterative algorithms for large sparse linear systems on parallel computers  

NASA Technical Reports Server (NTRS)

Algorithms for assembling in parallel the sparse system of linear equations that result from finite difference or finite element discretizations of elliptic partial differential equations, such as those that arise in structural engineering are developed. Parallel linear stationary iterative algorithms and parallel preconditioned conjugate gradient algorithms are developed for solving these systems. In addition, a model for comparing parallel algorithms on array architectures is developed and results of this model for the algorithms are given.

Adams, L. M.

1982-01-01

64

Progress on an ITER ECH Transmission system development and testing  

NASA Astrophysics Data System (ADS)

Progress on further development of the ITER ECH Transmission system design and testing of waveguide components will be presented. Work on the preliminary design of the system configuration is proceeding based on the conceptual design from the ITER Organization. Requirements for precision of waveguide supports and components are being analyzed and thermal and mechanical modeling of prototype components is being performed. Several prototype components have been procured from industry and some have been tested to nearly 1 MW at 170 GHz for long pulses at JAEA in Japan. A high power test stand is being developed at ORNL to provide component, system, and instrumentation tests at 1 MW cw or higher power conditions. The high voltage power supply has been tested and 140 GHz and 170 GHz gyrotrons are expected to be operational in the near future.

Bigelow, Tim; Hanson, Greg; Rasmussen, Dave; Barker, Alan; Dukes, Carl; Killough, Stephen; Peters, Brian; Rumbolt, Robin; Schaich, Chuck; Sanabria, Roberto; McElehaney, Karen; White, John; Allison, Stephen

2012-10-01

65

Progress on the heating and current drive systems for ITER  

SciTech Connect

The electron cyclotron (EC), ion cyclotron (IC), heating-neutral beam (H-NB) and, although not in the day 1 baseline, lower hybrid (LH) systems intended for ITER have been reviewed in 2007/2008 in light of progress of physics and technology in the field. Although the overall specifications are unchanged, notable changes have been approved. Firstly, it has been emphasized that the H&CD systems are vital for the ITER programme. Consequently, the full 73 MW should be commissioned and available on a routine basis before the D/T phase. Secondly, significant changes have been approved at system level, most notably: the possibility to operate the heating beams at full power during the hydrogen phase requiring new shine through protection; the possibility to operate IC with 2 antennas with increased robustness (no moving parts); the possible increase to 2 MW of key components of the EC transmission systems in order to provide an easier upgrading of the EC power as may be required by the project; the addition of a building dedicated to the RF power sources and to a testing facility for acceptance of diagnostics and heating port plugs. Thirdly, the need of a plan for developing, in time for the active phase, a CD system such as LH suitable for very long pulse operation of ITER was recognised. The review describes these changes and their rationale.

Jacquinot, J. [CEA, Cadarache, France; Beaumont, Bertrand [ITER Joint Work Site, Cadarache; Bora, D. [ITER Joint Work Site, Cadarache; Campbell, D. [ITER Joint Work Site, Cadarache; Darbos, Caroline [ITER Joint Work Site, Cadarache; Decamps, H. [ITER Organization, Saint Paul Lez Durance, France; Graceffa, J. [ITER Joint Work Site, Cadarache; Gassmann, T. [ITER Joint Work Site, Cadarache; Hemsworth, R. [ITER Joint Work Site, Cadarache; Henderson, Mark [ITER Joint Work Site, Cadarache; Kobayashi, N. [ITER Joint Work Site, Cadarache; Lamalle, Philippe [ITER Joint Work Site, Cadarache; Schunke, B. [ITER Joint Work Site, Cadarache; Tanaka, M. [ITER Joint Work Site, Cadarache; Tanga, A. [ITER Joint Work Site, Cadarache; Albajar, F. [Fusion for Energy (F4E), Barcelona, Spain; Bonicelli, T. [Fusion for Energy (F4E), Barcelona, Spain; Saibene, G. [Fusion for Energy (F4E), Barcelona, Spain; Sartori, R. [Fusion for Energy (F4E), Barcelona, Spain; Becoulet, A. [CEA, Cadarache, France; Hoang, G. T. [CEA, Cadarache, France; Inoue, T. [Japan Atomic Energy Agency (JAEA), Naka; Sakamoto, K. [Japan Atomic Energy Agency (JAEA), Naka; Takahashi, K. [Japan Atomic Energy Agency (JAEA), Naka; Watanabe, K. [Japan Atomic Energy Agency (JAEA), Naka; Goulding, Richard Howell [ORNL; Rasmussen, David A [ORNL; Swain, David W [ORNL; Chakraborty, A. [ITER India - Bhat, Gandhinagar, Gujarat; Mukherjee, A. [ITER India - Bhat, Gandhinagar, Gujarat; Rao, S. L. [ITER India - Bhat, Gandhinagar, Gujarat; Denisov, G. [Russian Academy of Science, Novgorod, Russia; Nightingale, M. [EURATOM / UKAEA, Abingdon, UK; Sonato, P. [EURATOM / ENEA, Italy

2009-06-01

66

Laser power beaming system analyses  

NASA Technical Reports Server (NTRS)

The successful demonstration of the PAMELA adaptive optics hardware and the fabrication of the BTOS truss structure were identified by the program office as the two most critical elements of the NASA power beaming program, so it was these that received attention during this program. Much of the effort was expended in direct program support at MSFC, but detailed technical analyses of the AMP deterministic control scheme and the BTOS truss structure (both the JPL design and a spherical one) were prepared and are attached, and recommendations are given.

Zeiders, Glenn W., Jr.

1993-01-01

67

Development of the ITER ICH Transmission Line and Matching System  

NASA Astrophysics Data System (ADS)

The ITER Ion Cyclotron Heating (ICH) System is designed to couple 20 MW of heating power for ion and electron heating. Prototype components for the ITER Ion Cyclotron Heating (ICH) transmission line and matching system are being designed and tested. The ICH transmission lines are pressurized 300 mm diameter coaxial lines with water-cooled aluminum outer conductor and gas-cooled and water-cooled copper inner conductor. Each ICH transmission line is designed to handle 40- 55 MHz power at up to 6 MW/line. A total of 8 lines split to 16 antenna inputs on two ICH antennas. Industrial suppliers have designed coaxial transmission line and matching components and prototypes will be manufactured. The prototype components will be qualified on a test stand operating at the full power and pulse length needed for ITER. The matching system must accommodated dynamic changes in the plasma loading due to ELMS and the L to H-mode transition. Passive ELM tolerance will be performed using hybrid couplers and loads, which can absorb the transient reflected power. The system is also designed to compensate for the mutual inductances of the antenna current straps to limit the peak voltages on the antenna array elements.

Rasmussen, D. A.; Goulding, R. H.; Pesavento, P. V.; Peters, B.; Swain, D. W.; Fredd, E. H.; Hosea, J.; Greenough, N.

2011-11-01

68

Design options for an ITER ion cyclotron system  

SciTech Connect

Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10--20 cm. Designs of a conventional strap launcher and a folded waveguide launcher than can meet the new requirements are presented.

Swain, D.W.; Baity, F.W.; Bigelow, T.S.; Ryan, P.M.; Goulding, R.H.; Carter, M.D.; Stallings, D.C.; Batchelor, D.B.; Hoffman, D.J.

1995-09-01

69

Neutron activation system using water flow for ITER  

NASA Astrophysics Data System (ADS)

A neutron activation system with flowing water using the 16O(n,p)16N reaction has been designed for the International Thermonuclear Experimental Reaction (ITER) neutron yield monitor with temporal resolution, based on the experimental results carried out at the fusion neutronics source (FNS) facility of the Japan Atomic Energy Research Institute. On ITER, irradiation ends will be installed in the filler shielding module between the blanket modules at the equatorial ports. The gamma-ray counting stations will be installed on the upstairs of the pit outside the biological shield. BGO (Bi4Ge3O12) scintillation detectors will be employed to measure 6.13 MeV gamma rays emitted from 16N. The distance between the irradiation end and the counting station is ~20 m. The performance of the neutron activation system has been evaluated by using the neutron Monte Carlo code MCNP-4b with the JENDL 3.2 library. The reaction rate of 16O(n,p)16N was calculated not only at the irradiation end but also along the transfer line, which showed that the temporal resolution would be less than the ITER requirement of 100 ms including turbulent diffusion effects for the flow velocity of 10 m/s. With a flow velocity of 10 m/s, this system can measure the fusion power from 50 kW to 1 GW of the ITER operation by using two gamma-ray detectors; one detector faces the water pipe directly, and another has a collimator for higher-neutron yield. Also the calculation shows that the reaction rate is relatively insensitive to the change of the plasma position.

Nishitani, T.; Ebisawa, K.; Kasai, S.; Walker, C.

2003-03-01

70

Operation mode studies of the ITER cryodistribution system  

NASA Astrophysics Data System (ADS)

In order to achieve and maintain the proper cryogenic conditions for fusion experiments, the ITER Cryogenic System has to cope with various operation modes as per the requirements of the superconducting (SC) magnets and the 4 K Cryopumps (CPs). The refrigerators, source of the cooling power, should operate as much as possible in a quasisteady- state manner for efficiency and reliability reasons, and also to optimize their cooling capacity. The cryogen-related transients generated or required by the magnets and CPs therefore have to be managed and smoothed inside the primary helium loops of the Cryodistribution (CD) cold boxes which distribute and recover the cooling flows. In this proceeding we will propose the internal-component layouts of the ITER CD cold boxes and demonstrate in terms of operation modes how they fulfill the duties of the Cryogenic System with respect to the ITER Tokamak. The methods foreseen for the smoothing of the cryogenic loads and optimization of the cooling power requirements will also be introduced.

Chang, Hyun-Sik; Serio, Luigi; Henry, Denis; Chalifour, Michel; Forgeas, Adrien

2012-06-01

71

Newton iterative methods for large scale nonlinear systems  

SciTech Connect

Objective is to develop robust, efficient Newton iterative methods for general large scale problems well suited for discretizations of partial differential equations, integral equations, and other continuous problems. A concomitant objective is to develop improved iterative linear algebra methods. We first outline research on Newton iterative methods and then review work on iterative linear algebra methods. (DLC)

Walker, H.F.; Turner, K.

1993-01-01

72

Multilevel iteration for mixed finite element systems with penalty  

SciTech Connect

In this paper, the authors consider the solution of the discrete systems that arises when a mixed finite element approach is used to approximate the solution of second-order elliptic boundary value problems. By the introduction of a penalty parameter, these equations can be approximated by the solution of a symmetric and positive definite penalty system on the velocity subspace. Iterative procedures are developed and analyzed for this penalty system based on the hierarchical basis approach as well as on the standard multigrid approach. Finally, numerical experiments are presented that illustrate the convergence behavior suggested by the theory.

Zhiqiang Cai (Univ. of Southern California, Los Angeles, CA (United States). Dept. of Mathematics); Goldstein, C.I.; Pasciak, J.E. (Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science)

1993-09-01

73

Status of the ITER IC H&CD System  

NASA Astrophysics Data System (ADS)

The ITER Ion Cyclotron Heating and Current Drive system will deliver 20 MW of radio frequency power to the plasma in quasi continuous operation during the different phases of the experimental programme. The system also has to perform conditioning of the tokamak first wall at low power between main plasma discharges. This broad range of requirements imposes a high flexibility and a high availability. The paper highlights the physics and design requirements on the IC system, the main features of its subsystems, the predicted performance, and the current procurement and installation schedule.

Lamalle, P. U.; Beaumont, B.; Gassmann, T.; Kazarian, F.; Arambhadiya, B.; Bora, D.; Jacquinot, J.; Mitteau, R.; Schüller, F. C.; Tanga, A.; Baruah, U.; Bhardwaj, A.; Kumar, R.; Mukherjee, A.; Singh, N. P.; Singh, R.; Goulding, R.; Rasmussen, D.; Swain, D.; Agarici, G.; Sartori, R.; Borthwick, A.; Davis, A.; Fanthome, J.; Hamlyn-Harris, C.; Hancock, A. D.; Kaye, A.; Lockley, D.; Nightingale, M.; Dumortier, P.; Durodié, F.; Grine, D.; Koch, R.; Louche, F.; Lyssoivan, A.; Messiaen, A.; Tamain, P.; Vervier, M.; Weynants, R. R.; Maggiora, R.; Milanesio, D.; Braun, F.; Noterdaeme, J.-M.; Vulliez, K.

2009-11-01

74

Status of the ITER IC H and CD System  

SciTech Connect

The ITER Ion Cyclotron Heating and Current Drive system will deliver 20 MW of radio frequency power to the plasma in quasi continuous operation during the different phases of the experimental programme. The system also has to perform conditioning of the tokamak first wall at low power between main plasma discharges. This broad range of requirements imposes a high flexibility and a high availability. The paper highlights the physics and design requirements on the IC system, the main features of its subsystems, the predicted performance, and the current procurement and installation schedule.

Lamalle, P. U.; Beaumont, B.; Gassmann, T.; Kazarian, F.; Arambhadiya, B.; Bora, D.; Jacquinot, J.; Mitteau, R.; Schueller, F. C.; Tanga, A. [ITER Organization, CS 90 046, 13067 Saint-Paul-Lez-Durance (France); Baruah, U.; Bhardwaj, A.; Kumar, R.; Mukherjee, A.; Singh, N. P.; Singh, R. [ITER India, A29, Sector 25, GIDC, Gandhinagar, Gujarat (India); Goulding, R.; Rasmussen, D.; Swain, D. [US ITER Project Office, Oak Ridge National Laboratory, P.O. Box 2008, 1055 CM, MS 6483, Oak Ridge, TN 37831-6483 (United States); Agarici, G. [Fusion for Energy, Josep Pla 2, 08019 Barcelona (Spain)] (and others)

2009-11-26

75

Process Flow and Functional Analysis of the Iter Cryogenic System  

NASA Astrophysics Data System (ADS)

The ITER cryogenic system is presently under design by a large international collaboration. It will start commissioning at Cadarache, south of France in 2015. The system is designed to provide an equivalent refrigeration capacity of 65 kW at 4.5 K for the superconducting magnet and 1300 kW at 80 K for the cryoplant pre-cooling stages and the Cryostat Thermal Shields (CTS). The cryoplant consists of three 4.5 K refrigerators and two 80 K helium loops coupled with two LN2 modules. Two 4.5 K modules are dedicated to the magnet system and a small one is devoted to the cryopumps and Pellet Injection System. One Interconnection box interfaces the cryoplant and a complex cryodistribution system which includes 5 Auxiliary Cold Boxes dedicated to each cryogenic subsystem. The ITER cryogenic system will have to cope with various normal and abnormal operational modes including superconducting magnets quench recovery and fast energy discharge. We will present the general Process Flow Diagram of the cryoplant and cryodistribution system and the operation requirements. The functional analysis of the cryogenic system will be performed leading to a proposal of the cryogenic control system architecture. The instrumentation and control requirements will also be outlined.

Henry, D.; Chalifour, M.; Forgeas, A.; Kalinin, V.; Monneret, E.; Serio, L.; Vincent, G.; Voigt, T.

2010-04-01

76

Aviation System Analysis Capability Executive Assistant Analyses  

NASA Technical Reports Server (NTRS)

This document describes the analyses that may be incorporated into the Aviation System Analysis Capability Executive Assistant. The document will be used as a discussion tool to enable NASA and other integrated aviation system entities to evaluate, discuss, and prioritize analyses.

Roberts, Eileen; Kostiuk, Peter

1999-01-01

77

ITER cryogenic system validation tests at helios test facility  

NASA Astrophysics Data System (ADS)

The ITER cryogenic system will have to cope with substantial dynamic heat loads due to the magnetic field variation and the production of neutrons generated by the fusion reactions. This will induce large pressure variations in the primary cooling loop of the superconducting coils, which results in the large power variation to the helium refrigerator. The HELIOS test facility, developed at CEA-Grenoble, and initially designed to study the pulse mitigation of the JT-60SA central solenoid cooling circuit (in order to smooth the pulsed load and test components), was adapted to the ITER cooling loop requirements. This paper presents the experimental results concerning the specific ITER analysis. We reproduce experimentally the pressure variation of the Central Solenoid (CS) loop predicted by a numerical model, and observe the behaviour of the circulating pump in these conditions. The investigations of the heat load smoothing methods, using the circuit of Toroidal Field Structures, such as the pulse mitigation by temporary by-pass of the flow of the Structure cooling loop, and variation of the speed of the cold circulating pump, are also presented.

Vallcorba-Carbonell, Roser; Rousset, Bernard; Poncet, Jean-Marc; Chang, Hyun-Sik; Forgeas, Adrien; Maekawa, Ryugi; Serio, Luigi; Bonnay, Patrick; Bon-Mardion, Michel; Girard, Alain; Hoa, Christine; Lagier, Benjamin; Michel, Frederic; Roussel, Pascal

2012-06-01

78

Polychromator for the edge Thomson scattering system in ITER.  

PubMed

A new type polychromator has been designed for the edge Thomson scattering system in ITER. Signal light is parallelly dispersed into two parts at the first interference filter. Spectral transmissivities for some spectral channels may enhance better than the conventional type polychromator. In the new type polychromator, the misalignment due to the machine accuracy is expected to be within the margin of APD area. In order to calibrate the spectral transmissivity using the dual-laser injection method during the plasma discharge, it is preferred that the spectral channels are separated at the geometric mean of the injected two wavelengths. PMID:23126986

Yatsuka, E; Hatae, T; Fujie, D; Kurokawa, A; Kusama, Y

2012-10-01

79

ITER ICH Transmission Line and Matching System Prototype Development  

NASA Astrophysics Data System (ADS)

Design and testing of prototype components for the ITER Ion Cyclotron Heating (ICH) transmission line and matching system is underway. Each ICH transmission line is designed to handle up to 6 MW/line in the 40-55 MHz frequency range. A total of 8 lines split to 16 antenna inputs on two ICH antennas. The ICH system is made up of 14 types of unique coaxial transmission line and matching components. The matching system is designed to provide passive ELM tolerance through the use of hybrid couplers and loads, which can absorb the transient reflected power. In addition the system is designed to compensate for coupling between antenna inputs caused by the mutual inductances of the current straps. It is further designed to balance as much as reasonable, the power requirements from the sources and the peak voltages on the antenna array elements.

Rasmussen, D. A.; Swain, D. W.; Goulding, R. H.; Pesavento, P. V.; Peters, B.; Fredd, E. H.; Hosea, J.; Greenough, N.

2011-12-01

80

Convergence Acceleration of Iterative Signal Detection for MIMO System with Belief Propagation  

NASA Astrophysics Data System (ADS)

In multiple-input multiple-output (MIMO) wireless systems, the receiver must extract each transmitted signal from received signals. Iterative signal detection with belief propagation (BP) can improve the error rate performance, by increasing the number of detection and decoding iterations in MIMO systems. This number of iterations is, however, limited in actual systems because each additional iteration increases latency, receiver size, and so on. This paper proposes a convergence acceleration technique that can achieve better error rate performance with fewer iterations than the conventional iterative signal detection. Since the Log-Likelihood Ratio (LLR) of one bit propagates to all other bits with BP, improving some LLRs improves overall decoder performance. In our proposal, all the coded bits are divided into groups and only one group is detected in each iterative signal detection whereas in the conventional approach, each iterative signal detection run processes all coded bits, simultaneously. Our proposal increases the frequency of initial LLR update by increasing the number of iterative signal detections and decreasing the number of coded bits that the receiver detects in one iterative signal detection. Computer simulations show that our proposal achieves better error rate performance with fewer detection and decoding iterations than the conventional approach.

Gounai, Satoshi; Ohtsuki, Tomoaki

81

Parallel, iterative solution of sparse linear systems: Models and architectures  

NASA Technical Reports Server (NTRS)

A model of a general class of asynchronous, iterative solution methods for linear systems is developed. In the model, the system is solved by creating several cooperating tasks that each compute a portion of the solution vector. A data transfer model predicting both the probability that data must be transferred between two tasks and the amount of data to be transferred is presented. This model is used to derive an execution time model for predicting parallel execution time and an optimal number of tasks given the dimension and sparsity of the coefficient matrix and the costs of computation, synchronization, and communication. The suitability of different parallel architectures for solving randomly sparse linear systems is discussed. Based on the complexity of task scheduling, one parallel architecture, based on a broadcast bus, is presented and analyzed.

Reed, D. A.; Patrick, M. L.

1984-01-01

82

Iterative Development of Visual Control Systems in a Research Vivarium  

PubMed Central

The goal of this study was to test the hypothesis that reintroduction of Continuous Performance Improvement (CPI) methodology, a lean approach to management at Seattle Children’s (Hospital, Research Institute, Foundation), would facilitate engagement of vivarium employees in the development and sustainment of a daily management system and a work-in-process board. Such engagement was implemented through reintroduction of aspects of the Toyota Production System. Iterations of a Work-In-Process Board were generated using Shewhart’s Plan-Do-Check-Act process improvement cycle. Specific attention was given to the importance of detecting and preventing errors through assessment of the following 5 levels of quality: Level 1, customer inspects; Level 2, company inspects; Level 3, work unit inspects; Level 4, self-inspection; Level 5, mistake proofing. A functioning iteration of a Mouse Cage Work-In-Process Board was eventually established using electronic data entry, an improvement that increased the quality level from 1 to 3 while reducing wasteful steps, handoffs and queues. A visual workplace was realized via a daily management system that included a Work-In-Process Board, a problem solving board and two Heijunka boards. One Heijunka board tracked cage changing as a function of a biological kanban, which was validated via ammonia levels. A 17% reduction in cage changing frequency provided vivarium staff with additional time to support Institute researchers in their mutual goal of advancing cures for pediatric diseases. Cage washing metrics demonstrated an improvement in the flow continuum in which a traditional batch and queue push system was replaced with a supermarket-type pull system. Staff engagement during the improvement process was challenging and is discussed. The collective data indicate that the hypothesis was found to be true. The reintroduction of CPI into daily work in the vivarium is consistent with the 4P Model of the Toyota Way and selected Principles that guide implementation of the Toyota Production System.

Bassuk, James A.; Washington, Ida M.

2014-01-01

83

Iterative development of visual control systems in a research vivarium.  

PubMed

The goal of this study was to test the hypothesis that reintroduction of Continuous Performance Improvement (CPI) methodology, a lean approach to management at Seattle Children's (Hospital, Research Institute, Foundation), would facilitate engagement of vivarium employees in the development and sustainment of a daily management system and a work-in-process board. Such engagement was implemented through reintroduction of aspects of the Toyota Production System. Iterations of a Work-In-Process Board were generated using Shewhart's Plan-Do-Check-Act process improvement cycle. Specific attention was given to the importance of detecting and preventing errors through assessment of the following 5 levels of quality: Level 1, customer inspects; Level 2, company inspects; Level 3, work unit inspects; Level 4, self-inspection; Level 5, mistake proofing. A functioning iteration of a Mouse Cage Work-In-Process Board was eventually established using electronic data entry, an improvement that increased the quality level from 1 to 3 while reducing wasteful steps, handoffs and queues. A visual workplace was realized via a daily management system that included a Work-In-Process Board, a problem solving board and two Heijunka boards. One Heijunka board tracked cage changing as a function of a biological kanban, which was validated via ammonia levels. A 17% reduction in cage changing frequency provided vivarium staff with additional time to support Institute researchers in their mutual goal of advancing cures for pediatric diseases. Cage washing metrics demonstrated an improvement in the flow continuum in which a traditional batch and queue push system was replaced with a supermarket-type pull system. Staff engagement during the improvement process was challenging and is discussed. The collective data indicate that the hypothesis was found to be true. The reintroduction of CPI into daily work in the vivarium is consistent with the 4P Model of the Toyota Way and selected Principles that guide implementation of the Toyota Production System. PMID:24736460

Bassuk, James A; Washington, Ida M

2014-01-01

84

Chevron beam dump for ITER edge Thomson scattering system  

SciTech Connect

This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

Yatsuka, E.; Hatae, T.; Bassan, M.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)] [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Vayakis, G. [ITER Organization, 13115 St Paul Lez Durance Cedex (France)] [ITER Organization, 13115 St Paul Lez Durance Cedex (France)

2013-10-15

85

Chevron beam dump for ITER edge Thomson scattering system.  

PubMed

This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated. PMID:24182106

Yatsuka, E; Hatae, T; Vayakis, G; Bassan, M; Itami, K

2013-10-01

86

Chevron beam dump for ITER edge Thomson scattering system  

NASA Astrophysics Data System (ADS)

This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

Yatsuka, E.; Hatae, T.; Vayakis, G.; Bassan, M.; Itami, K.

2013-10-01

87

Iterated function system models in data analysis: Detection and separation  

NASA Astrophysics Data System (ADS)

We investigate the use of iterated function system (IFS) models for data analysis. An IFS is a discrete-time dynamical system in which each time step corresponds to the application of one of the finite collection of maps. The maps, which represent distinct dynamical regimes, may be selected deterministically or stochastically. Given a time series from an IFS, our algorithm detects the sequence of regime switches under the assumption that each map is continuous. This method is tested on a simple example and an experimental computer performance data set. This methodology has a wide range of potential uses: from change-point detection in time-series data to the field of digital communications.

Alexander, Zachary; Meiss, James D.; Bradley, Elizabeth; Garland, Joshua

2012-06-01

88

Conceptual design of ACB-CP for ITER cryogenic system  

NASA Astrophysics Data System (ADS)

ACB-CP (Auxiliary Cold Box for Cryopumps) is used to supply the cryopumps system with necessary cryogen in ITER (International Thermonuclear Experimental Reactor) cryogenic distribution system. The conceptual design of ACB-CP contains thermo-hydraulic analysis, 3D structure design and strength checking. Through the thermohydraulic analysis, the main specifications of process valves, pressure safety valves, pipes, heat exchangers can be decided. During the 3D structure design process, vacuum requirement, adiabatic requirement, assembly constraints and maintenance requirement have been considered to arrange the pipes, valves and other components. The strength checking has been performed to crosscheck if the 3D design meets the strength requirements for the ACB-CP.

Jiang, Yongcheng; Xiong, Lianyou; Peng, Nan; Tang, Jiancheng; Liu, Liqiang; Zhang, Liang

2012-06-01

89

Iterative Repair Planning for Spacecraft Operations Using the Aspen System  

NASA Technical Reports Server (NTRS)

This paper describes the Automated Scheduling and Planning Environment (ASPEN). ASPEN encodes complex spacecraft knowledge of operability constraints, flight rules, spacecraft hardware, science experiments and operations procedures to allow for automated generation of low level spacecraft sequences. Using a technique called iterative repair, ASPEN classifies constraint violations (i.e., conflicts) and attempts to repair each by performing a planning or scheduling operation. It must reason about which conflict to resolve first and what repair method to try for the given conflict. ASPEN is currently being utilized in the development of automated planner/scheduler systems for several spacecraft, including the UFO-1 naval communications satellite and the Citizen Explorer (CX1) satellite, as well as for planetary rover operations and antenna ground systems automation. This paper focuses on the algorithm and search strategies employed by ASPEN to resolve spacecraft operations constraints, as well as the data structures for representing these constraints.

Rabideau, G.; Knight, R.; Chien, S.; Fukunaga, A.; Govindjee, A.

2000-01-01

90

On the JET ITER-Like ICRF antenna and implications for the ICRF system for ITER  

Microsoft Academic Search

A new ``ITER-Like'' Ion Cyclotron Resonance Frequency (ICRF) antenna was installed on the JET tokamak in 2007 and extensively operated on plasma since May 2008 for a wide range of conditions (frequencies: 33, 42 and 47 MHz, L- and ELMy H-mode plasmas, antenna strap - plasma separatrix distances from 9 to 17 cm). Aspects relating to the potential performance and

Frederic Durodie; Mark Nightingale

2009-01-01

91

Evaluation of biological dose rates around the ITER NBI ports by 2-D S n\\/activation and 3-D Monte Carlo analyses  

Microsoft Academic Search

Shielding analyses for the International Thermonuclear Experimental Reactor (ITER) neutral beam injector (NBI) ports have been performed using two-dimensional discrete ordinates Sn method with activation analyses and three-dimensional Monte Carlo method. From the two-dimensional Sn\\/activation analyses, it was found that a conversion ratio relating fast neutron flux to the biological dose rates at 106 s after reactor shutdown is 1.5–2.0×10?5

Satoshi Sato; Hiromasa Iida; Romano Plenteda; Davide Valenza; Robert T Santoro

2000-01-01

92

Conceptual design of a High Temperature Superconductor current feeder system for ITER  

Microsoft Academic Search

The International Thermonuclear Experimental Reactor (ITER) project envisages a techno-economically feasible solution of its current feeder system in order to reduce the overall cryogenic requirements and operational costs. Since the ITER magnet system has a long stand-by time with respect to its operation duty cycle, it is essential to optimize the operational costs of the current feeder system taking into

V L Tanna; W H Fietz; R Heller; A Vostner; R Wesche; G R Zahn

2006-01-01

93

Filtered propagator functional for iterative dynamics of quantum dissipative systems  

NASA Astrophysics Data System (ADS)

We describe a Fortran program which calculates the reduced density matrix of a one-dimensional quantum mechanical continuous or discrete system coupled to a harmonic dissipative environment. The algorithm is based on Feynman's path integral formulation of time-dependent quantum mechanics. An adiabatic reference is employed to obtain accurate propagators and the harmonic bath is replaced by an influence functional which is discretized by optimal discrete variable representations. A propagator functional of statistically significant path segments is constructed which allows iterative evaluation of the path integral over long time periods. High efficiency is achieved with the aid of sorting and filtering criteria. The appended program is executable in either serial or parallel mode.

Sim, Eunji; Makri, Nancy

1997-01-01

94

Dynamic Performance of the ITER Reactive Power Compensation System  

NASA Astrophysics Data System (ADS)

Dynamic performance of a reactive power compensation (RPC) system for the international thermonuclear experimental reactor (ITER) power supply is presented. Static var compensators (SVCs) are adopted to mitigate voltage fluctuation and reduce the reactive power down to a level acceptable for the French/European 400 kV grid. A voltage feedback and load power feedforward controller for SVC is proposed, with the feedforward loop intended to guarantee short response time and the feedback loop ensuring good dynamics and steady characteristics of SVC. A mean filter was chosen to measure the control signals to improve the dynamic response. The dynamic performance of the SVC is verified by simulations using PSCAD/EMTDC codes.

Sheng, Zhicai; Fu, Peng; Xu, Liuwei

2011-10-01

95

Investigation of ``Conjugate T'' Load-Resilient ICRF Antenna Systems - Application to the JET ITER-Like and to a Possible ITER ICRF System  

Microsoft Academic Search

The paper reports on the radio-frequency (RF) analysis of multiple-short-strap load-resilient ICRF antenna systems, applied to the JET ITER-Like and to a proposed ITER ICRF system. The short radiating straps minimize the antenna voltage and the ``conjugate T'' load resilient matching circuit aims at reliable power delivery to ELMy H mode plasmas. The two designs mainly differ by the use

P. U. Lamalle; A. M. Messiaen; P. Dumortier; F. Durodié; M. Evrard; F. Louche; M. Vervier; R. Weynants

2005-01-01

96

The Parallel Solution of Systems of Linear Equations using Iterative Methods on Transputer Networks  

Microsoft Academic Search

We present a study of the implementational aspects of iterative methods to solve systems of linear equations on a transputer network. Both dense and sparse systems are considered. First we discuss the implementation of a set of distributed l inear algebra subroutines which are used as building blocks for implementing the iterative methods. We show that the use of loop-unrolling

Rudnei Dias da Cunha; Tim Hopkins

1992-01-01

97

Existence and iterative approximation of solutions of a system of general variational inclusions  

Microsoft Academic Search

In this paper, we consider a system of general variational inclusions in q-uniformly smooth Banach spaces. Using proximal-point mapping technique, we prove the existence and uniqueness of solution and suggest a Mann type perturbed iterative algorithm for the system of general variational inclusions. We also discuss the convergence criteria and stability of Mann type perturbed iterative algorithm. The techniques and

K. R. Kazmi; Huzoor H. Khan; Naeem Ahmad

2009-01-01

98

An iterative multiuser receiver using groupwise MLSE and interference cancellation in a MC-CDMA system  

Microsoft Academic Search

We propose a low-complexity iterative multiuser receiver using groupwise maximum likelihood sequence estimation (MLSE) combined with interference cancellation for a turbo coded MC-CDMA system. It is based on grouping the active users according to their signal strengths and computing the log-likelihood ratios by using MLSE in each group at the first iteration. For subsequent iterations, a modified interference cancellation scheme

P. L. Kafle; Abu B. Sesay

2002-01-01

99

Analysis of the ITER ICRH Decoupling and Matching System  

SciTech Connect

The reference ITER ICRH load resilient matching system uses four 3dB hybrid power splitters. It is proposed to use a 'double stub' tuner (DST) configuration for the matching on the reference load and a decoupling system placed between the antenna plug and the matching system to reduce the mutual coupling effects and also to actively control the array current spectrum while requesting the same forward power from all 4 power sources. The paper analyzes (i) the optimization of the matching layout e.g. by varying the distance between the stubs and by the use of two capacitors taking into account the role of the decouplers on the matching requirements; (ii) the practical realization of the decouplers and their insertion into the circuit; (iii) the requests in voltage and current capabilities in the different parts of the system. The paper presents solutions for saving space and to decrease the ratings of the components. The computations are done with the array loading simulated by the TOPICA matrix.

Vervier, M.; Messiaen, A.; Dumortier, P. [Plasma Physics Laboratory, Royal Military Academy, Brussels, Belgium, TEC Partner (Belgium)

2009-11-26

100

An Overview Of The ITER In-Vessel Coil Systems  

SciTech Connect

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

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

2009-09-24

101

AM laser system (IVVS) for the ITER in vessel viewing and ranging  

Microsoft Academic Search

In vessel inspection (viewing and ranging) systems, able to withstand the International Thermonuclear Experimental Reactor (ITER) very severe operating conditions, are fundamental to check plasma facing components in order to properly program ordinary and extraordinary maintenance activities. In this field different schemes have been proposed during the EDA ITER phase each of them showing problems in ranging and\\/or in radiation

A. Coletti; L. Bartolini; M. Ferri De Collibus; G. Fornetti; A. Lo Bue; S. Lupini; C. Neri; F. Pollastrone; L. Semeraro; C. Talarico

2003-01-01

102

Policy iteration adaptive dynamic programming algorithm for discrete-time nonlinear systems.  

PubMed

This paper is concerned with a new discrete-time policy iteration adaptive dynamic programming (ADP) method for solving the infinite horizon optimal control problem of nonlinear systems. The idea is to use an iterative ADP technique to obtain the iterative control law, which optimizes the iterative performance index function. The main contribution of this paper is to analyze the convergence and stability properties of policy iteration method for discrete-time nonlinear systems for the first time. It shows that the iterative performance index function is nonincreasingly convergent to the optimal solution of the Hamilton-Jacobi-Bellman equation. It is also proven that any of the iterative control laws can stabilize the nonlinear systems. Neural networks are used to approximate the performance index function and compute the optimal control law, respectively, for facilitating the implementation of the iterative ADP algorithm, where the convergence of the weight matrices is analyzed. Finally, the numerical results and analysis are presented to illustrate the performance of the developed method. PMID:24807455

Liu, Derong; Wei, Qinglai

2014-03-01

103

Transportation systems analyses: Volume 1: Executive Summary  

NASA Astrophysics Data System (ADS)

The principal objective of this study is to accomplish a systems engineering assessment of the nation's space transportation infrastructure. This analysis addresses the necessary elements to perform man delivery and return, cargo transfer, cargo delivery, payload servicing, and the exploration of the Moon and Mars. Specific elements analyzed, but not limited to, include the Space Exploration Initiative (SEI), the National Launch System (NLS), the current expendable launch vehicle (ELV) fleet, ground facilities, the Space Station Freedom (SSF), and other civil, military and commercial payloads. The performance of this study entails maintaining a broad perspective on the large number of transportation elements that could potentially comprise the U.S. space infrastructure over the next several decades. To perform this systems evaluation, top-level trade studies are conducted to enhance our understanding of the relationships between elements of the infrastructure. This broad 'infrastructure-level perspective' permits the identification of preferred infrastructures. Sensitivity analyses are performed to assure the credibility and usefulness of study results. This executive summary of the transportation systems analyses (TSM) semi-annual report addresses the SSF logistics resupply. Our analysis parallels the ongoing NASA SSF redesign effort. Therefore, there could be no SSF design to drive our logistics analysis. Consequently, the analysis attempted to bound the reasonable SSF design possibilities (and the subsequent transportation implications). No other strategy really exists until after a final decision is rendered on the SSF configuration.

1993-05-01

104

Used Fuel Management System Interface Analyses - 13578  

SciTech Connect

Preliminary system-level analyses of the interfaces between at-reactor used fuel management, consolidated storage facilities, and disposal facilities, along with the development of supporting logistics simulation tools, have been initiated to provide the U.S. Department of Energy (DOE) and other stakeholders with information regarding the various alternatives for managing used nuclear fuel (UNF) generated by the current fleet of light water reactors operating in the United States. An important UNF management system interface consideration is the need for ultimate disposal of UNF assemblies contained in waste packages that are sized to be compatible with different geologic media. Thermal analyses indicate that waste package sizes for the geologic media under consideration by the Used Fuel Disposition Campaign may be significantly smaller than the canisters being used for on-site dry storage by the nuclear utilities. Therefore, at some point along the UNF disposition pathway, there could be a need to repackage fuel assemblies already loaded and being loaded into the dry storage canisters currently in use. The implications of where and when the packaging or repackaging of commercial UNF will occur are key questions being addressed in this evaluation. The analysis demonstrated that thermal considerations will have a major impact on the operation of the system and that acceptance priority, rates, and facility start dates have significant system implications. (authors)

Howard, Robert; Busch, Ingrid [Oak Ridge National Laboratory, P.O. Box 2008, Bldg. 5700, MS-6170, Oak Ridge, TN 37831 (United States)] [Oak Ridge National Laboratory, P.O. Box 2008, Bldg. 5700, MS-6170, Oak Ridge, TN 37831 (United States); Nutt, Mark; Morris, Edgar; Puig, Francesc [Argonne National Laboratory (United States)] [Argonne National Laboratory (United States); Carter, Joe; Delley, Alexcia; Rodwell, Phillip [Savannah River National Laboratory (United States)] [Savannah River National Laboratory (United States); Hardin, Ernest; Kalinina, Elena [Sandia National Laboratories (United States)] [Sandia National Laboratories (United States); Clark, Robert [U.S. Department of Energy (United States)] [U.S. Department of Energy (United States); Cotton, Thomas [Complex Systems Group (United States)] [Complex Systems Group (United States)

2013-07-01

105

An accelerated iterative method for the dynamics of constrained multibody systems  

NASA Astrophysics Data System (ADS)

An accelerated iterative method is suggested for the dynamic analysis of multibody systems consisting of interconnected rigid bodies. The Lagrange multipliers associated with the kinematic constraints are iteratively computed by the monotone reduction of the constraint error vector, and the resulting equations of motion are easily time-integrated by a well established ODE technique. The velocity and acceleration constraints as well as the position constraints are made to be satisfied at the joints at each time step. Exact solution is obtained without the time demanding procedures such as selection of the independent coordinates, decomposition of the constraint Jacobian matrix, and Newton Raphson iterations. An acceleration technique is employed for the faster convergence of the iterative scheme and the convergence analysis of the proposed iterative method is presented. Numerical solutions for the verification problems are presented to demonstrate the efficiency and accuracy of the suggested technique.

Lee, Kisu

1993-01-01

106

A global secant relaxation (GSR) method-based predictor-corrector procedure for the iterative solution of finite element systems  

Microsoft Academic Search

In this paper, an iterative procedure based on improving the diagonal stiffness prediction is used to solve general finite element systems. The procedure consists of a predictor and a corrector, for each iteration step, iteratively obtaining the converged solution. The diagonal stiffness prediction works to predict an incremental response vector for the discrete algebraic system, while the global secant relaxation

Chang-New Chen

1995-01-01

107

Transportation systems analyses. Volume 1: Executive summary  

NASA Astrophysics Data System (ADS)

The principal objective is to accomplish a systems engineering assessment of the nation's space transportation infrastructure. This analysis addresses the necessary elements to perform crew delivery and return, cargo transfer, cargo delivery and return, payload servicing, and the exploration of the Moon and Mars. Specific elements analyzed, but not limited to, include: the Space Exploration Initiative (SEI), the National Launch System (NLS), the current expendable launch vehicle (ELV) fleet, ground facilities, the Space Station Freedom (SSF), and other civil, military and commercial payloads. The performance of this study entails maintaining a broad perspective on the large number of transportation elements that could potentially comprise the U.S. space infrastructure over the next several decades. To perform this systems evaluation, top-level trade studies are conducted to enhance our understanding of the relationship between elements of the infrastructure. This broad 'infrastructure-level perspective' permits the identification of preferred infrastructures. Sensitivity analyses are performed to assure the credibility and usefulness of study results. Conceptual studies of transportation elements contribute to the systems approach by identifying elements (such as ETO node and transfer/excursion vehicles) needed in current and planned transportation systems. These studies are also a mechanism to integrate the results of relevant parallel studies.

1992-11-01

108

Physics basis for the application of electron cyclotron wave system on ITER and its technology  

Microsoft Academic Search

Electron cyclotron wave system on ITER will be used for plasma start-up heating and current drive. The underlying physics will be outlined. The requirements and the technical aspects of the two launchers will be described.

M. Q. Tran

2006-01-01

109

Variational iteration method for solving a nonlinear system of second-order boundary value problems  

Microsoft Academic Search

The variational iteration method is introduced to solve a nonlinear system of second-order boundary value problems. Numerical results demonstrate that this method is promising and readily implemented.

Junfeng Lu

2007-01-01

110

Active spectroscopic measurements using the ITER diagnostic system  

SciTech Connect

Active (beam-based) spectroscopic measurements are intended to provide a number of crucial parameters for the ITER device being built in Cadarache, France. These measurements include the determination of impurity ion temperatures, absolute densities, and velocity profiles, as well as the determination of the plasma current density profile. Because ITER will be the first experiment to study long timescale ({approx}1 h) fusion burn plasmas, of particular interest is the ability to study the profile of the thermalized helium ash resulting from the slowing down and confinement of the fusion alphas. These measurements will utilize both the 1 MeV heating neutral beams and a dedicated 100 keV hydrogen diagnostic neutral beam. A number of separate instruments are being designed and built by several of the ITER partners to meet the different spectroscopic measurement needs and to provide the maximum physics information. In this paper, we describe the planned measurements, the intended diagnostic ensemble, and we will discuss specific physics and engineering challenges for these measurements in ITER.

Thomas, D. M. [ITER Organization, 13067 St. Paul-lez-Durance Cedex (France); Counsell, G. [Fusion for Energy, 08019 Barcelona (Spain); Johnson, D. [US ITER Project Office, Oak Ridge, Tennessee 37830 (United States); Vasu, P. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Zvonkov, A. [Russian Research Center ''Kurchatov Institute'', Moscow 123182 (Russian Federation)

2010-10-15

111

Status of the ITER neutral beam injection system (invited)  

Microsoft Academic Search

The ITER neutral beam injectors are the first injectors to be designed to operate under conditions and constraints similar to those that will be encountered with a fusion reactor. The injectors will use a single large ion source and accelerator that will produce 40 A D- 1 MeV beams for pulse lengths of up to 3600 s. The accelerated ion

R. S. Hemsworth; A. Tanga; V. Antoni

2008-01-01

112

SLAVE: a genetic learning system based on an iterative approach  

Microsoft Academic Search

SLAVE is an inductive learning algorithm that uses concepts based on fuzzy logic theory. This theory has been shown to be a useful representational tool for improving the understanding of the knowledge obtained from a human point of view. Furthermore, SLAVE uses an iterative approach for learning based on the use of a genetic algorithm (GA) as a search algorithm.

A. Gonzblez; R. Perez

1999-01-01

113

Poloidal field system analysis and scenario development for ITER  

Microsoft Academic Search

ITER, the International Thermonuclear Experimental Reactor, is a collaborative design by the United States, Europe, Japan and the Soviet Union of a tokamak fusion reactor that would demonstrate the physics and test the technology needed for commercial fusion reactors. The poloidal field (PF) magnets are responsible for forming and shaping highly elongated, high current plasma, during a long-pulse burn. At

Schultz

1989-01-01

114

Iterative Repair Planning for Spacecraft Operations Using the ASPEN System  

Microsoft Academic Search

This paper describes the Automated Scheduling and Planning Environment (ASPEN). ASPEN encodes complex spacecraft knowledge of operabilit y constraints, flight rules, spacecraft hardware, scien ce experiments and operations procedures to allow for automated generation of low level spacecraft sequences. Using a technique called iterative repair, ASPEN classifies constraint violations (i.e., conflicts) and attempts to repair each by performing a planning

Gregg Rabideau; Russell Knight; Steve Chien; Alex Fukunaga; Anita Govindjee

1999-01-01

115

Analysis of iterative demapping and decoding for MBOK DS-UWB systems via EXIT chart  

Microsoft Academic Search

This paper presents an analysis of iterative demapping and decoding for coded M-ary bi-orthogonal keying direct sequence UWB (MBOK DS-UWB) systems via an extrinsic information transfer chart (EXIT chart). In MBOK DS-UWB systems, which have been considered a type of PHYs suitable for high-speed wireless personal area networks (WPANs) in IEEE802.15.3a, one of useful error correction techniques is iterative demapping

Kenichi Takizawa; Ryuji Kohno

2005-01-01

116

Iterative and Diversity Techniques for Uplink MC-CDMA Mobile Systems With Full Load  

Microsoft Academic Search

Iterative and diversity techniques are two of the most effective techniques for uplink multicarrier code-division multiple-access (MC-CDMA) systems. However, there is still no knowledge on how to efficiently combine these techniques to design high-performance uplink receivers when there is a complexity constraint. In this paper, we compare the performance and the complexity of MC-CDMA systems with and without iterative detectors

Yi Yuan-Wu; Ye Li

2008-01-01

117

Development of a YAG laser system for the edge Thomson scattering system in ITER.  

PubMed

A prototype YAG laser system for the edge Thomson scattering system in ITER has been newly developed. Performance of the laser amplifier was improved by using flow tubes made of samarium-doped glass; the small signal gain reached 20 at its maximum. As a result, an output energy of 7.66 J at 100 Hz was successfully achieved, and the performance exceeded the target performance (5 J, 100 Hz). PMID:23127001

Hatae, T; Yatsuka, E; Hayashi, T; Yoshida, H; Ono, T; Kusama, Y

2012-10-01

118

Development of a YAG laser system for the edge Thomson scattering system in ITER  

SciTech Connect

A prototype YAG laser system for the edge Thomson scattering system in ITER has been newly developed. Performance of the laser amplifier was improved by using flow tubes made of samarium-doped glass; the small signal gain reached 20 at its maximum. As a result, an output energy of 7.66 J at 100 Hz was successfully achieved, and the performance exceeded the target performance (5 J, 100 Hz).

Hatae, T.; Yatsuka, E.; Hayashi, T.; Ono, T.; Kusama, Y. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Ibaraki 311-0193 (Japan); Yoshida, H. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan)

2012-10-15

119

Frequency-Domain Equalization with Iterative Block Noise-Prediction for Single-Carrier Systems  

NASA Astrophysics Data System (ADS)

In this letter, we propose a novel frequency-domain equalizer (FDE) for single-carrier systems characterized by severe inter-symbol interference (ISI) channels; it consists of a linear FDE and an iterative block noise-predictor (IBNP). Unlike the FDE with time-domain noise predictor (FDE-NP), the proposed scheme allows the feedback equalizer being an uncausal filter, and performs the noise prediction in an iterative manner. For this reason, FDE-IBNP can remove both precursor and postcursor ISI, and alleviate the impact of error-propagation. Besides, our scheme has lower computational complexity than the present iterative block equalizers.

Feng, Ang; Yin, Qinye

120

A comparative study of iterative solutions to linear systems arising in quantum mechanics  

SciTech Connect

This study is mainly focused on iterative solutions with simple diagonal preconditioning to two complex-valued nonsymmetric systems of linear equations arising from a computational chemistry model problem proposed by Sherry Li of NERSC. Numerical experiments show the feasibility of iterative methods to some extent when applied to the problems and reveal the competitiveness of our recently proposed Lanczos biconjugate A-orthonormalization methods to other classic and popular iterative methods. By the way, experiment results also indicate that application specific preconditioners may be mandatory and required for accelerating convergence.

Jing Yanfei, E-mail: yanfeijing@uestc.edu.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Huang Tingzhu, E-mail: tzhuang@uestc.edu.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Duan Yong, E-mail: duanyong@yahoo.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Carpentieri, Bruno, E-mail: b.carpentieri@rug.n [Institute of Mathematics and Computing Science, University of Groningen, Nijenborgh 9, P.O. Box 407, 9700 AK Groningen (Netherlands)

2010-11-01

121

Thermo-mechanical analysis of ITER first mirrors and its use for the ITER equatorial visible/infrared wide angle viewing system optical design  

SciTech Connect

ITER first mirrors (FMs), as the first components of most ITER optical diagnostics, will be exposed to high plasma radiation flux and neutron load. To reduce the FMs heating and optical surface deformation induced during ITER operation, the use of relevant materials and cooling system are foreseen. The calculations led on different materials and FMs designs and geometries (100 mm and 200 mm) show that the use of CuCrZr and TZM, and a complex integrated cooling system can limit efficiently the FMs heating and reduce their optical surface deformation under plasma radiation flux and neutron load. These investigations were used to evaluate, for the ITER equatorial port visible/infrared wide angle viewing system, the impact of the FMs properties change during operation on the instrument main optical performances. The results obtained are presented and discussed.

Joanny, M.; Salasca, S.; Dapena, M.; Cantone, B.; Travere, J. M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Thellier, C.; Ferme, J. J. [THALES SESO, 13593 Aix-en-Provence Cedex 3 (France); Marot, L. [Department of Physics, University of Basel, 4056 Basel (Switzerland); Buravand, O. [Institut d'Optique Graduate School, 91127 Palaiseau (France); Perrollaz, G. [AMETRA, 13770 Venelles (France); Zeile, C. [INR, KIT, D-76344 Eggenstein-Leopoldshafen (Germany)

2012-10-15

122

Thermo-mechanical analysis of ITER first mirrors and its use for the ITER equatorial visible?infrared wide angle viewing system optical design.  

PubMed

ITER first mirrors (FMs), as the first components of most ITER optical diagnostics, will be exposed to high plasma radiation flux and neutron load. To reduce the FMs heating and optical surface deformation induced during ITER operation, the use of relevant materials and cooling system are foreseen. The calculations led on different materials and FMs designs and geometries (100 mm and 200 mm) show that the use of CuCrZr and TZM, and a complex integrated cooling system can limit efficiently the FMs heating and reduce their optical surface deformation under plasma radiation flux and neutron load. These investigations were used to evaluate, for the ITER equatorial port visible?infrared wide angle viewing system, the impact of the FMs properties change during operation on the instrument main optical performances. The results obtained are presented and discussed. PMID:23127013

Joanny, M; Salasca, S; Dapena, M; Cantone, B; Travère, J M; Thellier, C; Fermé, J J; Marot, L; Buravand, O; Perrollaz, G; Zeile, C

2012-10-01

123

Iterative methods as dynamical systems with feedback control  

Microsoft Academic Search

It is shown how standard iterative methods for solving linear and nonlinear equations can be approached from the point of view of control. Appropriate choices of control Lyapunov functions lead to both continuous and discrete-time versions of the well-known Newton-Raphson and conjugate gradient algorithms as well as their common variants. Insights into these algorithms that result from the control approach

Amit Bhaya; Eugenius Kaszkurewicz

2003-01-01

124

Pseudo Random Number Generation with the Aid of Iterated Function Systems on ?2  

NASA Astrophysics Data System (ADS)

Two new pseudorandom number generators, based on iterated function systems (IFS), are introduced. An IFS is created based on an arbitrary seed and a set is constructed using the deterministic iteration algorithm (DIA). From this set pseudo random numbers have been constructed. The generators have big periods and pass all major statistical tests, indicating that they can be used in any application requiring random numbers, such as cryptography.

Bouboulis, P.

125

Development of a Twin-Screw D-2 Extruder for the ITER Pellet Injection System  

Microsoft Academic Search

A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. The extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with single-stage gas gun into the plasma. A one-fifth ITER scale prototype extruder has been built to produce a continuous solid deuterium

Steven J Meitner; Larry R Baylor; Juan J Carbajo; Stephen Kirk Combs; Dan T Fehling; Charles R Foust; Marshall T McFee; James M McGill; David A Rasmussen; R G Sitterson; Dennis O Sparks; A L Qualls

2009-01-01

126

The multistage variational iteration method for a class of nonlinear system of ODEs  

Microsoft Academic Search

This paper implements the multistage variational iteration method (MVIM) to solve a class of nonlinear system of first-order ordinary differential equations (ODEs). The domain of validity of the solutions via the standard variational iteration method (VIM) is extended by the simple multistage strategy. Comparisons with the exact solution and the fourth-order Runge-Kutta (RK4) method show that the MVIM is a

B. Batiha; M. S. M. Noorani; I. Hashim; E. S. Ismail

2007-01-01

127

Development of the prototype pneumatic transfer system for ITER neutron activation system.  

PubMed

The neutron activation system (NAS) measures neutron fluence at the first wall and the total neutron flux from the ITER plasma, providing evaluation of the fusion power for all operational phases. The pneumatic transfer system (PTS) is one of the key components of the NAS for the proper operation of the system, playing a role of transferring encapsulated samples between the capsule loading machine, irradiation stations, counting stations, and disposal bin. For the validation and the optimization of the design, a prototype of the PTS was developed and capsule transfer tests were performed with the developed system. PMID:23126830

Cheon, M S; Seon, C R; Pak, S; Lee, H G; Bertalot, L

2012-10-01

128

Development of the prototype pneumatic transfer system for ITER neutron activation system  

SciTech Connect

The neutron activation system (NAS) measures neutron fluence at the first wall and the total neutron flux from the ITER plasma, providing evaluation of the fusion power for all operational phases. The pneumatic transfer system (PTS) is one of the key components of the NAS for the proper operation of the system, playing a role of transferring encapsulated samples between the capsule loading machine, irradiation stations, counting stations, and disposal bin. For the validation and the optimization of the design, a prototype of the PTS was developed and capsule transfer tests were performed with the developed system.

Cheon, M. S.; Seon, C. R.; Pak, S.; Lee, H. G. [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Bertalot, L. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2012-10-15

129

Combined application of Product Lifecycle and Software Configuration Management systems for ITER remote handling  

Microsoft Academic Search

The advantages of Product Lifecycle Management (PLM) systems are widely understood among the industry and hence a PLM system is already in use by International Thermonuclear Experimental Reactor (ITER) Organization (IO). However, with the increasing involvement of software in the development, the role of Software Configuration Management (SCM) systems have become equally important. The SCM systems can be useful to

Ali Muhammad; Salvador Esque; Liisa Aha; Jouni Mattila; Mikko Siuko; Matti Vilenius; Jorma Järvenpää; Mike Irving; Carlo Damiani; Luigi Semeraro

2009-01-01

130

Investigation of 'Conjugate T' Load-Resilient ICRF Antenna Systems - Application to the JET ITER-Like and to a Possible ITER ICRF System  

SciTech Connect

The paper reports on the radio-frequency (RF) analysis of multiple-short-strap load-resilient ICRF antenna systems, applied to the JET ITER-Like and to a proposed ITER ICRF system. The short radiating straps minimize the antenna voltage and the 'conjugate T' load resilient matching circuit aims at reliable power delivery to ELMy H mode plasmas. The two designs mainly differ by the use of in-vessel matching capacitors for the JET array, whereas the proposed ITER design uses an optimized combination of straps in parallel and ex-vessel matching by means of line stretchers. Asymmetries and mutual coupling between straps strongly influence the performance of such load-resilient circuits and complicate their operation. These effects have been analyzed in detail along two parallel lines of investigation: (i) Detailed RF simulations, in which the input impedance matrix of the ICRF arrays has been computed with a three-dimensional electromagnetic code and incorporated in realistic models of the transmission and matching circuits, (ii) Comprehensive RF measurements on a scaled-down mockup of the proposed ITER antenna. Ongoing work to optimize array performance and to develop practical matching procedures and reliable automatic control of the matching elements is discussed. The main outstanding issues are reliable arc detection and demonstration of a robust array control algorithm.

Lamalle, P.U.; Messiaen, A.M.; Dumortier, P.; Durodie, F.; Evrard, M.; Louche, F.; Vervier, M.; Weynants, R. [Laboratory for Plasma Physics, Association EURATOM - Belgian State, Partner in the Trilateral Euregio Cluster, Royal Military Academy, 30 av. de la Renaissance, B-1000 Brussels (Belgium)

2005-09-26

131

Global ICRF system designs for ITER and TPX  

SciTech Connect

The design of feed networks for ICRF antenna arrays on ITER and TPX are discussed. Features which are present in one or both of the designs include distribution of power to several straps from a single generator, the capability to vary phases of the currents on antenna elements rapidly without the need to rematch, and passive elements which present a nearly constant load to the generators during ELM induced loading transients of a factor of 10 or more. The FDAC (Feedline/Decoupler/Antenna Calculator) network modeling code is described, which allows convenient modeling of the electrical performance of nearly arbitrary ICRF feed networks. {copyright} {ital 1996 American Institute of Physics.}

Goulding, R.H.; Hoffman, D.J.; Ryan, P.M. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-8071 (United States); Durodie, F. [Laboratoire de Physique des Plasmas-Association ``EURATOM-Etat Belge``-Ecole Royale Militaire-B1040 Brussels (Belgium)

1996-02-01

132

El Paso Electric photovoltaic-system analyses  

SciTech Connect

Four analyses were performed on the Newman Power Station PV system. Two were performed using the Photovoltaic Transient Analysis Program (PV-TAP) and two with the SOLCEL II code. The first was to determine the optimum tilt angle for the array and the sensitivity of the annual energy production to variation in tilt angle. The optimum tilt angle was found to be 28/sup 0/, and variations of 2/sup 0/ produce losses of only 0.06% in the annual energy production. The second analysis assesses the power loss due to cell-to-cell variations in short circuit current and the degree of improvement attainable by sorting cells and matching modules. Typical distributions on short circuit current can cause losses of about 9.5 to 11 percent in peak array power, and sorting cells into 4 bins prior to module assembly can reduce the losses to about 6 to 8 percent. Using modules from the same cell bins in building series strings can reduce the losses to about 4.5 to 6 percent. Results are nearly the same if the array is operated at a fixed votage. The third study quantifies the magnitude and frequency of occurrence of high cell temperatures due to reverse bias caused by shadowing, and it demonstrates that cell temperatures achieved in reverse bias are higher for cells with larger shunt resistance. The last study assesses the adequacy of transient protection devices on the dc power lines to transients produced by array switching and lightning. Large surge capacitors on the dc power line effectively limit voltage excursions at the array and at the control room due to lightning. Without insertion of series resistors, the current may be limited only by cable and switch impedances, and all elements could be severely stressed. (LEW)

Not Available

1982-05-01

133

Conceptual design of fusion experimental reactor (FER/ITER). Ion cyclotron wave system.  

National Technical Information Service (NTIS)

Conceptual design of the Ion Cyclotron Wave (ICW) system for FER and Japanese contribution to the conceptual design of the ITER ICW system are presented. A frequency range of the FER ICW system is 50-85 MHz, which covers 2(omega)(sub cT) heating, current ...

H. Kimura M. Saigusa Y. Saitoh

1991-01-01

134

ITER plasma equilibrium and poloidal field system design  

SciTech Connect

Several poloidal field coil design issues are identified when assessing the benefits of high plasma elongaton in an ITER device. Among these are the sensitivity of PF ampere-turens and coil energy to specific constraints on the plasma shape and profiles and the optimal placement of PF coils subject to assumed operating scenarios. Two versons of free boundary equilibrium codes presently under development at the Oak Ridge National Laboratory (ORNL), HEQ and VEQ, are used to solve several PF design problems related to these issues. Recent efforts have been directed toward problems in the analysis of highly elongated, magnetically-limited plasmas, such as X-point and divertor strike-point placement and control. In this report, we describe the capabilities of HEQ and discuss the major options available to the user. Applications of HEQ and VEQ in the area of plasma elongation tradeoff studies are presented. 8 refs., 4 figs., 4 tabs.

Strickler, D.J.; Galambos, J.D.; Peng, Y.K.M.

1988-01-01

135

Status of the ITER neutral beam injection system (invited)  

NASA Astrophysics Data System (ADS)

The ITER neutral beam injectors are the first injectors to be designed to operate under conditions and constraints similar to those that will be encountered with a fusion reactor. The injectors will use a single large ion source and accelerator that will produce 40 A D- 1 MeV beams for pulse lengths of up to 3600 s. The accelerated ion beams will be neutralized in a gas (D2) neutralizer which is subdivided into four vertical channels to reduce the gas flow into the injectors that is needed to produce optimum target for neutralization. These injectors will have to operate in a hostile radiation environment and they will become highly radioactive due to the neutron flux from ITER. The design has been modified recently to have a rectangular vacuum vessel with a removable lid that allows vertical access to, and maintenance of, the beamline components, the incorporation of an absolute all metal valve at the exit of the injector, the choice of a rf driven ion source as the reference design of ion source, and to have a high voltage deck incorporating the various auxiliary power supplies in air rather that under high pressure SF6. A major development is that it has been agreed that a Neutral Beam Test Facility (NBTF) will be set up at Padua, Italy. The NBTF will consist of two test beds: one of which will be capable of operating a complete injector at full performance. The second will be an ion source test bed, which will be used for the development and testing, to full performance, of the large negative ion source.

Hemsworth, R. S.; Tanga, A.; Antoni, V.

2008-02-01

136

Status of the ITER neutral beam injection system (invited)  

SciTech Connect

The ITER neutral beam injectors are the first injectors to be designed to operate under conditions and constraints similar to those that will be encountered with a fusion reactor. The injectors will use a single large ion source and accelerator that will produce 40 A D{sup -} 1 MeV beams for pulse lengths of up to 3600 s. The accelerated ion beams will be neutralized in a gas (D{sub 2}) neutralizer which is subdivided into four vertical channels to reduce the gas flow into the injectors that is needed to produce optimum target for neutralization. These injectors will have to operate in a hostile radiation environment and they will become highly radioactive due to the neutron flux from ITER. The design has been modified recently to have a rectangular vacuum vessel with a removable lid that allows vertical access to, and maintenance of, the beamline components, the incorporation of an absolute all metal valve at the exit of the injector, the choice of a rf driven ion source as the reference design of ion source, and to have a high voltage deck incorporating the various auxiliary power supplies in air rather that under high pressure SF{sub 6}. A major development is that it has been agreed that a Neutral Beam Test Facility (NBTF) will be set up at Padua, Italy. The NBTF will consist of two test beds: one of which will be capable of operating a complete injector at full performance. The second will be an ion source test bed, which will be used for the development and testing, to full performance, of the large negative ion source.

Hemsworth, R. S.; Tanga, A.; Antoni, V. [ITER, ITER Joint Work Site, CEA Cadarache, 13108 St Paul lez Durance Cedex (France); Consorzio RFX, Association EURATOM-ENEA, I-35127 Padova (Italy)

2008-02-15

137

Results of Iterative Standards-Setting Procedures for a Performance-Based System for Renewable Certification.  

ERIC Educational Resources Information Center

This report presents the results of an initial, iterative performance standards-setting (SS) task of a comprehensive on-the-job statewide teacher assessment system--the System for Teaching and Learning Assessment and Review (STAR). The 1990-91 STAR assesses and makes inferences about the quality of teaching and learning on sets of assessment…

Lofton, Glenda G.; And Others

138

Linear quadratic Gaussian controller design for plasma current, position and shape control system in ITER  

Microsoft Academic Search

This paper is focused on the linear quadratic Gaussian (LQG) controller synthesis methodology for the ITER plasma current, position and shape control system as well as power derivative management system. It has been shown that some poloidal field (PF) coils have less influence on reference plasma-wall gaps control during plasma disturbances and hence they have been used to reduce total

V Belyakov; A Kavin; V Kharitonov; B Misenov; Y Mitrishkin; A Ovsyannikov; D Ovsyannikov; E Rumyantsev; E Veremei; A Zhabko

1999-01-01

139

GA-based iterative learning control applications to the weighing system of large asphalt mixing plant  

Microsoft Academic Search

In large asphalt mixing plant, the matching accuracy and the measuring precision of the material are critical to the final asphalt mixture. This paper firstly deducts the mathematical model of the weighing system of large asphalt mixing plant. Then a genetic algorithms based iterative learning controller for the weighing system is designed. Finally, computer simulation and experimental study are performed.

S. L. Song; J. Yan; Q. Zhang; Q. C. Zhou; W. L. Li; D. W. Zuo; C. Y. Xiao

2008-01-01

140

He's variational iteration method for solving linear and non-linear systems of ordinary differential equations  

Microsoft Academic Search

In this article, He’s variational iteration method (VIM) is employed to solve a system of differential equations of first order. Since every ordinary differential equations of higher order can be converted into a system of differential of the first order, this method can be used for solving most differential equations. Some examples are presented to show the ability of the

J. Biazar; H. Ghazvini

2007-01-01

141

Steady state and dynamic simulation of the ITER hydrogen isotope separation system  

SciTech Connect

Steady state and dynamic simulation studies of the ITER Hydrogen Isotope Separation System (ISS) are presented. Ontario Hydro`s FLOSHFET code is used as the reference code for design studies of the ISS. Dynamic simulation are also carried out using Ontario Hydro`s DYNSIM code. The ITER ISS dynamic simulation is important because it allows study of product quality control schemes and control system design. It also allows accurate assessment of tritium inventory variation in different operating modes. The cryogenic distillation model in the new DYNSIM code is described including the underlying theory and numerical simulation approach. 9 refs., 3 figs.

Busigin, A. [NITEK Corp., London (Canada); Sood, S.K. [Ontario Hydro, Toronto (Canada)

1995-10-01

142

Iterative solution of large, sparse linear systems on a static data flow architecture - Performance studies  

NASA Technical Reports Server (NTRS)

The applicability of static data flow architectures to the iterative solution of sparse linear systems of equations is investigated. An analytic performance model of a static data flow computation is developed. This model includes both spatial parallelism, concurrent execution in multiple PE's, and pipelining, the streaming of data from array memories through the PE's. The performance model is used to analyze a row partitioned iterative algorithm for solving sparse linear systems of algebraic equations. Based on this analysis, design parameters for the static data flow architecture as a function of matrix sparsity and dimension are proposed.

Reed, D. A.; Patrick, M. L.

1985-01-01

143

On the HSS iteration methods for positive definite Toeplitz linear systems  

NASA Astrophysics Data System (ADS)

We study the HSS iteration method for large sparse non-Hermitian positive definite Toeplitz linear systems, which first appears in Bai, Golub and Ng's paper published in 2003 [Z.-Z. Bai, G.H. Golub, M.K. Ng, Hermitian and skew-Hermitian splitting methods for non-Hermitian positive definite linear systems, SIAM J. Matrix Anal. Appl. 24 (2003) 603-626], and HSS stands for the Hermitian and skew-Hermitian splitting of the coefficient matrix A. In this note we use the HSS iteration method based on a special case of the HSS splitting, where the symmetric part is a centrosymmetric matrix and the skew-symmetric part is a skew-centrosymmetric matrix for a given Toeplitz matrix. Hence, fast methods are available for computing the two half-steps involved in the HSS and IHSS iteration methods. Some numerical results illustrate their effectiveness.

Gu, Chuanqing; Tian, Zhaolu

2009-02-01

144

Turbo Iterative Signal Processing  

Microsoft Academic Search

A Turbo iterative method for signal processing is proposed. This method is a kind of multi-systems collaborative signal processing through iteration: several independent systems work in rotation, and each system takes feedback information from the other systems as a priori condition. We have applied such a Turbo iterative signal processing (TISP) method on speech signal enhancement, and on SAR (synthetic

Hong Sun; Henri Maître

2009-01-01

145

US ITER Moving Forward  

ScienceCinema

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

US ITER / ORNL

2012-03-16

146

US ITER Moving Forward  

SciTech Connect

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

US ITER / ORNL

2012-01-01

147

System Requirement Analyses for Ubiquitous Environment Management System  

NASA Astrophysics Data System (ADS)

We are living in new stage of society. U-City introduces new paradigm that cannot be archived in traditional city to future city. Korea is one of the most active countries to construct U-City based on advances of IT technologies - especially based on high-speed network through out country [1]. Peoples are realizing ubiquitous service is key factor of success of U-City. Among the U-services, U-security service is one of the most important services. Nowadays we have to concern about traditional threat and also personal information. Since apartment complex is the most common residence type in Korea. We are developing security rules and system based on analyses of apartment complex and assert of apartment complex. Based on these analyses, we are developing apartment complex security using various technologies including home network system. We also will discuss basic home network security architecture.

Lim, Sang Boem; Gil, Kyung Jun; Choe, Ho Rim; Eo, Yang Dam

148

Total-system performance assessment for Yucca Mountain -- SNL second iteration (TSPA-1993); Executive summary  

SciTech Connect

Sandia National Laboratories has completed the second iteration of the periodic total-system performance assessments (TSPA-93) for the Yucca Mountain Site Characterization Project (YMP). Scenarios describing expected conditions (aqueous and gaseous transport of contaminants) and low-probability events (human-intrusion drilling and volcanic intrusion) are modeled. The hydrologic processes modeled include estimates of the perturbations to ambient conditions caused by heating of the repository resulting from radioactive decay of the waste. TSPA-93 incorporates significant new detailed process modeling, including two- and three-dimensional modeling of thermal effects, groundwater flow in the saturated-zone aquifers, and gas flow in the unsaturated zone. Probabilistic analyses are performed for aqueous and gaseous flow and transport, human intrusion, and basaltic magmatic activity. Results of the calculations lead to a number of recommendations concerning studies related to site characterization. Primary among these are the recommendations to obtain better information on percolation flux at Yucca Mountain, on the presence or absence of flowing fractures, and on physical and chemical processes influencing gaseous flow. Near-field thermal and chemical processes, and waste-container degradation are also areas where additional investigations may reduce important uncertainties. Recommendations for repository and waste-package design studies are: (1) to evaluate the performance implications of large-size containers, and (2) to investigate in more detail the implications of high repository thermal power output on the adjacent host rock and on the spent fuel.

Wilson, M.L.; Barnard, R.W. [Sandia National Labs., Albuquerque, NM (United States); Gauthier, J.H. [Sandia National Labs., Albuquerque, NM (United States)]|[Spectra Research, Inc. (United States)] [and others

1994-04-01

149

ASTP communications systems analyses and performance predictions  

NASA Technical Reports Server (NTRS)

A research program was conducted to provide ASTP mission communication coverage and performance analyses and to analyze anomalies and special compatibility problems as they arise. The end product of the contract was spacecraft-to-ground communications performance predictions for the ASTP mission, both for direct communication links to ground and for those links via the ATS-6 relay satellite to ground. Solutions are given for the special mission anomalies and compatibility problems encountered. A brief summary describing the work activities expended is given.

1975-01-01

150

Conceptual design of a High Temperature Superconductor current feeder system for ITER  

NASA Astrophysics Data System (ADS)

The International Thermonuclear Experimental Reactor (ITER) project envisages a techno-economically feasible solution of its current feeder system in order to reduce the overall cryogenic requirements and operational costs. Since the ITER magnet system has a long stand-by time with respect to its operation duty cycle, it is essential to optimize the operational costs of the current feeder system taking into consideration both, the full current and stand-by modes. The present HTS technology has reached the maturity that HTS conductors are applicable for the current feeder system of ITER. The replacement of the actually planned conventional current leads by HTS current leads would provide considerable savings in the refrigeration investment and operational costs. Another option is the substitution of the water cooled high current aluminum feeders by HTS feeders, so called HTS bus bars. In this paper, the different design options of Bi-2223/Ag HTS based bus bars as prototype unit modules for ITER are discussed. The performance of different cooling schemes for HTS bus bars is studied and the design related critical issues e.g. metallic transition (65 K -300 K) and bending of bus bar, AC loss, thermal loss and reliability of the cooling system are investigated.

Tanna, V. L.; Fietz, W. H.; Heller, R.; Vostner, A.; Wesche, R.; Zahn, G. R.

2006-06-01

151

An iterative inter-track interference mitigation method for two-dimensional magnetic recording systems  

NASA Astrophysics Data System (ADS)

At high recording density, the readback signal of two-dimensional magnetic recording is inevitably corrupted by the two-dimensional (2D) interference consisting of inter-symbol interference and inter-track interference (ITI), which can significantly degrade the overall system performance. This paper proposes an iterative ITI mitigation method using three modified 2D soft-output Viterbi algorithm (2D-SOVA) detectors in conjunction with an iterative processing technique to combat the 2D interference. The codeword of the outer code is divided and then written on three separate tracks. For every iteration, all 2D-SOVA detectors exchange the soft information to improve the reliability of the a priori information and use it in the branch metric calculation, before feeding the refined soft information to the outer decoder. Simulation results show that the proposed method outperforms the conventional receiver and the existing partial ITI mitigation method.

Warisarn, C.; Losuwan, T.; Supnithi, P.; Kovintavewat, P.

2014-05-01

152

An iterative pilot-data-aided estimator for SFBC relay-assisted OFDM-based systems  

NASA Astrophysics Data System (ADS)

In this article, we propose and assess an iterative pilot-data-aided channel estimation scheme for space frequency block coding relay-assisted OFDM-based systems. The relay node (RN) employs the equalise-and-forward protocol, and both the base station (BS) and the RN are equipped with antenna arrays, whereas the user terminal (UT) is a single-antenna device. The channel estimation method uses the information carried by pilots and data to improve the estimate of the equivalent channels for the path BS-RN-UT. The mean minimum square error criterion is used in the design of the estimator for both the pilot-based and data-aided iterations. In different scenarios, with only one data iteration, the results show that the proposed scheme requires only half of the pilot density to achieve the same performance of non-data-aided schemes.

Neves, Darlene; Ribeiro, Carlos; Silva, Adão; Gameiro, Atílio

2012-12-01

153

A coherent FM laser radar based system for remote metrology in ITER  

SciTech Connect

The plasma facing surfaces in ITER must be aligned to millimeter accuracy with respect to the magnetic flux surfaces to prevent impurity influx into the plasma and to avoid component damage. Checking of in-vessel component alignment during initial assembly, operation, and subsequent maintenance is anticipated. A fully remote metrology system is necessary, particularly since major remote operations such as shield blanket exchange and divertor cassette replacement are planned. The metrology system must be compatible with the ITER in-vessel environment of high gamma radiation ({approximately} 10{sup 6} R/hr), super-clean ultra-high-vacuum ({approximately} 10{sup {minus}8} Torr), and elevated temperature ({approximately}200 C). A fast scanning rate is required since the plasma facing surface in ITER is very large ({approximately} 1,500 m{sup 2}). A coherent FM laser radar based metrology system, developed by Coleman Research Corporation, is being adopted to accomplish this task. Conceptually, this metrology system consists of a compact (few cm{sup 3}) remotely deployed laser transceiver optics module, linked through fiber optics to the laser source and imaging units that are located outside the biological shield. Range measurements conducted on a variety of surfaces using the system have yielded sub-millimeter accuracy. Therefore, the technique will easily meet the precision requirement for the ITER application. Computer simulations have been carried out to determine the optimum number of units required for complete mapping of the plasma facing surfaces. Most in-vessel components of the system appear to be radiation hardenable and vacuum compatible. Details of the system and developments required to make it fully compatible for ITER metrology application will be elaborated.

Barry, R.E.; Burgess, T.W.; Menon, M.M. [Oak Ridge National Lab., TN (United States). Robotics and Process Systems Div.; Slotwinski, A.; Sebastian, R. [Coleman Research Corp., Springfield, VA (United States)

1995-12-31

154

A coherent FM laser radar based system for remote metrology in ITER  

Microsoft Academic Search

The plasma facing surfaces in ITER must be aligned to millimeter accuracy with respect to the magnetic flux surfaces to prevent impurity influx into the plasma and to avoid component damage. Checking of in-vessel component alignment during initial assembly, operation, and subsequent maintenance is anticipated. A fully remote metrology system is necessary, particularly since major remote operations such as shield

R. E. Barry; T. W. Burgess; M. M. Menon; A. Slotwinski; R. Sebastian

1995-01-01

155

2-D Reflectometer Modeling for Optimizing the ITER Low-Field Side Reflectometer System.  

National Technical Information Service (NTIS)

The response of a low-field side reflectometer system for ITER is simulated with a 2-D reflectometer code using a realistic plasma equilibrium. It is found that the reflected beam will often miss its launch point by as much as 40 cm and that a vertical ar...

G. J. Kramer R. Nazikian E. J. Valeo R. V. Budny C. Kessel

2005-01-01

156

Operational Experience with the Scattering Matrix Arc Detection System on the JET ITER-Like Antenna  

Microsoft Academic Search

The Scattering Matrix Arc Detection System (SMAD) has been fully deployed on all 4 sets of Resonant Double Loop (RDL), Vacuum Transmission Line (VTL) and Antenna Pressurised Transmission Lines (APTL) of the JET ICRF ITER-Like Antenna (ILA) and this has been indispensable for operating at low (real) T-point impedance values to investigate ELM tolerance. This paper describes the necessity of

M. Vrancken; E. Lerche; T. Blackman; P. Dumortier; F. Durodié; M. Evrard; R. H. Goulding; M. Graham; S. Huygen; P. Jacquet; A. Kaye; M.-L. Mayoral; M. P. S. Nightingale; J. Ongena; D. van Eester; M. van Schoor; M. Vervier; R. Weynants; JET-EFDA contributors

2009-01-01

157

The European test blanket module systems: Design and integration in ITER  

Microsoft Academic Search

The European Union proposes two different concepts of helium-cooled blanket for testing in ITER, one with ceramic breeder and beryllium, the second with lithium lead as breeder and multiplier. Test blanket modules (TBM) for both blanket concepts and their auxiliary systems have being designed in the last 2 years; this paper presents the status of this work as reached in

L. V. Boccaccini; J.-F. Salavy; R. Lässer; A. Li Puma; R. Meyder; H. Neuberger; Y. Poitevin; G. Rampal

2006-01-01

158

Coded DS-CDMA Systems with Iterative Channel Estimation and no Pilot Symbols.  

National Technical Information Service (NTIS)

In this paper, we describe direct-sequence code-division multiple- access (DS-CDMA) systems with quadriphase-shift keying in which channel estimation, coherent demodulation, and decoding are iteratively performed without the use of any training or pilot s...

A. Mukherjee D. Torrieri H. M. Kwon

2010-01-01

159

Efficacy of variational iteration method for chaotic Genesio system – Classical and multistage approach  

Microsoft Academic Search

This is a case study of solving the Genesio system by using the classical variational iteration method (VIM) and a newly modified version called the multistage VIM (MVIM). VIM is an analytical technique that grants us a continuous representation of the approximate solution, which allows better information of the solution over the time interval. Unlike its counterpart, numerical techniques, such

S. M. Goh; M. S. M. Noorani; I. Hashim

2009-01-01

160

The variational iteration method for solving linear and nonlinear systems of PDEs  

Microsoft Academic Search

In this work, the variational iteration method (VIM) is used for analytic treatment of the linear and nonlinear systems of partial differential equations. The method reduces the calculation size and overcomes the difficulty of handling nonlinear terms. Numerical examples are examined to highlight the significant features of the VIM method. The method shows improvements over existing numerical techniques.

Abdul-Majid Wazwaz

2007-01-01

161

Convergence of the variational iteration method for solving linear systems of ODEs with constant coefficients  

Microsoft Academic Search

In this paper, He’s variational iteration method is applied for solving linear systems of ordinary differential equations with constant coefficients. A theorem for the convergence of the method is presented. Some illustrative examples are given to show the efficiency of the method.

Davod Khojasteh Salkuyeh

2008-01-01

162

Jackson System Development Analysed in Process Algebra,  

National Technical Information Service (NTIS)

Jackson system development (JSD) is one of the few system development methods to account for the dynamics of the universe of discourse (UoD) of a database. The report uses the algebraic theory of parallel communicating processes developed by Bergstra & Kl...

R. Wieringa

1988-01-01

163

Advances in Thermogravimetric Analyses of Elastomer Systems  

Microsoft Academic Search

Practical rubber formulations are complex mixtures of polymer (s), fillers, plasticizers, curatives, and processing aids. Classical methods exist for determining many of the components of these systems but are too time consuming for routine use in quality control or problem solving activities. Thus a need has existed for more rapid procedures. Previous studies of gum, compounded, and cured elastomers showed

John J. Maurer

1974-01-01

164

Systems Analyses of Advanced Brayton Cycles  

SciTech Connect

The main objective is to identify and assess advanced improvements to the Brayton Cycle (such as but not limited to firing temperature, pressure ratio, combustion techniques, intercooling, fuel or combustion air augmentation, enhanced blade cooling schemes) that will lead to significant performance improvements in coal based power systems. This assessment is conducted in the context of conceptual design studies (systems studies) that advance state-of-art Brayton cycles and result in coal based efficiencies equivalent to 65% + on natural gas basis (LHV), or approximately an 8% reduction in heat rate of an IGCC plant utilizing the H class steam cooled gas turbine. H class gas turbines are commercially offered by General Electric and Mitsubishi for natural gas based combined cycle applications with 60% efficiency (LHV) and it is expected that such machine will be offered for syngas applications within the next 10 years. The studies are being sufficiently detailed so that third parties will be able to validate portions or all of the studies. The designs and system studies are based on plants for near zero emissions (including CO{sub 2}). Also included in this program is the performance evaluation of other advanced technologies such as advanced compression concepts and the fuel cell based combined cycle. The objective of the fuel cell based combined cycle task is to identify the desired performance characteristics and design basis for a gas turbine that will be integrated with an SOFC in Integrated Gasification Fuel Cell (IGFC) applications. The goal is the conceptualization of near zero emission (including CO{sub 2} capture) integrated gasification power plants producing electricity as the principle product. The capability of such plants to coproduce H{sub 2} is qualitatively addressed. Since a total systems solution is critical to establishing a plant configuration worthy of a comprehensive market interest, a baseline IGCC plant scheme is developed and used to study how alternative process schemes and power cycles might be used and integrated to achieve higher systems efficiency. To achieve these design results, the total systems approach is taken requiring creative integration of the various process units within the plant. Advanced gas turbine based cycles for Integrated gasification Combined cycle (IGCC) applications are identified by a screening analysis and the more promising cycles recommended for detailed systems analysis. In the case of the IGFC task, the main objective is met by developing a steady-state simulation of the entire plant and then using dynamic simulations of the hybrid Solid Oxide Fuel Cell (SOFC)/Gas Turbine sub-system to investigate the turbo-machinery performance. From these investigations the desired performance characteristics and a basis for design of turbo-machinery for use in a fuel cell gas turbine power block is developed.

A.D. Rao; D.J. Francuz; J.D. Maclay; J. Brouwer; A. Verma; M. Li; G.S. Samuelsen

2008-09-30

165

Unsteady Analyses of Valve Systems in Rocket Engine Testing Environments.  

National Technical Information Service (NTIS)

This paper discusses simulation technology used to support the testing of rocket propulsion systems by performing high fidelity analyses of feed system components. A generalized multi-element framework has been used to perform simulations of control valve...

J. Shipman A. Hosangadi V. Ahuja

2004-01-01

166

Characterisation of the SubHarmonic Arc Detection System on JET ITER-Like Antenna  

Microsoft Academic Search

A Sub-Harmonic Arc Detection (SHAD) system has been installed on the transmission lines feeding the JET ICRF ITER-like-Antenna (ILA). Along with the commissioning of SHAD, extensive measurements of the RF field in the transmission lines were carried-out using fast sampling (125 Mb\\/s) oscilloscopes. The system is described, and the SHAD ability to detect arcs during ILA operation (in particular on

P. Jacquet; G. Berger-By; V. Bobkov; T. Blackman; F. Durodié; M.-L. Mayoral; M. Nightingale; JET-EFDA contributors

2009-01-01

167

Construction of iteration functions for the simultaneous computation of the solutions of equations and algebraic systems  

NASA Astrophysics Data System (ADS)

We construct iteration functions for the simultaneous computation of the solutions of a system of equations, with local quadratic convergence: they generalize to the multivariate case the well-known Weierstrass function for polynomials, which is expected to be globally convergent except on a zero-measured set of starting points. We clarify these functions using univariate interpolation. Both for polynomials and algebraic systems with real coefficients, we extend the conjecture of global convergence to the research of real roots or solutions.

Bellido, Anne-Mercedes

1994-09-01

168

Variational Iterative Methods for Nonsymmetric Systems of Linear Equations.  

National Technical Information Service (NTIS)

We consider a class of interative algorithms for solving systems of linear equations where the coefficient matrix is nonsymmetric with positive-definite symmetric part. The algorithms are modelled after the conjugate gradient method, and are well-suited f...

S. C. Eisenstat H. C. Elman M. H. Schultz

1981-01-01

169

A laser scanning system for metrology and viewing in ITER  

SciTech Connect

The construction and operation of a next-generation fusion reactor will require metrology to achieve and verify precise alignment of plasma-facing components and inspection in the reactor vessel. The system must be compatible with the vessel environment of high gamma radiation (10{sup 4} Gy/h), ultra-high-vacuum (10{sup {minus}8} torr), and elevated temperature (200 C). The high radiation requires that the system be remotely deployed. A coherent frequency modulated laser radar-based system will be integrated with a remotely operated deployment mechanism to meet these requirements. The metrology/viewing system consists of a compact laser transceiver optics module which is linked through fiber optics to the laser source and imaging units that are located outside of a biological shield. The deployment mechanism will be a mast-like positioning system. Radiation-damage tests will be conducted on critical sensor components at Oak Ridge National Laboratory to determine threshold damage levels and effects on data transmission. This paper identifies the requirements for International Thermonuclear Experimental Reactor metrology and viewing and describes a remotely operated precision ranging and surface mapping system.

Spampinato, P.T.; Barry, R.E.; Menon, M.M.; Herndon, J.N. [Oak Ridge National Lab., TN (United States); Dagher, M.A.; Maslakowski, J.E. [Rockwell Rocketdyne Div., Canoga Park, CA (United States)

1996-05-01

170

Pole placement and order reduction in two-time-scale control systems through Riccati iteration  

NASA Technical Reports Server (NTRS)

A transformation of variables taken from singular perturbations may be applied to two-time-scale linear systems in state space form to reduce the system to block-diagonal form with slow and fast modes decoupled. The transformation is easily computed by applying the new Riccati iteration. The iteration yields a solution to the nonsymmetric algebraic Riccati equation obtained by partitioning the original system matrix A. The numerical procedure is initiated with the trivial iterate L(0) = 0, and is globally convergent to the desired unique time scale decoupling solution. After transformation, the decoupled system may be used in controller design to achieve exact closed loop pole placement in the slow subsystem without altering the poles of the fast subsystem. The decoupled form may also be used to reduce system order by wetting a small parameter to zero. Provided the fast subsystem is stable, the order reduction can be expected to yield a good approximation to the original system. These methods are demonstrated using the 16th order linear model of a turbofan engine.

Anderson, L. R.

1982-01-01

171

Design of the RTO\\/RC ITER primary pumping system  

Microsoft Academic Search

The primary pumping system is needed not only to exhaust helium ash resulting from the DT reaction but also excess fuelling gas injected during the fusion burn, which can extend for 100's to 1000's of seconds, and to perform a variety of other functions. The prevailing environmental conditions, principally nuclear radiation, tritium exposure, magnetic fields, and the need for containment,

P Ladd; C Ibbott; G Janeschitz; E Martin

2000-01-01

172

ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE ITER  

EPA Science Inventory

In Fall 1994, anaerobic compost wetlands in both upflow and downflow configurations were constructed adjacent to and received drainage from the Burleigh Tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The e...

173

A neutral particle beam system for ITER with RF acceleration  

Microsoft Academic Search

A concept for a current drive system that is based on negative ions with beam energies >1 MeV is presented. Preliminary physics calculations, which are discussed, show that the core current necessary for stability enhancement can be achieved by beams with energy ranging from 1 to 3 MeV. Further study and experiments will better define the optimum energy. Work under

W. L. Stirling; W. R. Becraft; J. H. Whealton; H. H. Haselton

1989-01-01

174

Total-system performance assessment for Yucca Mountain - SNL second iteration (TSPA-1993); Volume 2  

SciTech Connect

Sandia National Laboratories has completed the second iteration of the periodic total-system performance assessments (TSPA-93) for the Yucca Mountain Site Characterization Project (YMP). These analyses estimate the future behavior of a potential repository for high-level nuclear waste at the Yucca Mountain, Nevada, site under consideration by the Department of Energy. TSPA-93 builds upon previous efforts by emphasizing YMP concerns relating to site characterization, design, and regulatory compliance. Scenarios describing expected conditions (aqueous and gaseous transport of contaminants) and low-probability events (human-intrusion drilling and volcanic intrusion) are modeled. The hydrologic processes modeled include estimates of the perturbations to ambient conditions caused by heating of the repository resulting from radioactive decay of the waste. Hydrologic parameters and parameter probability distributions have been derived from available site data. Possible future climate changes are modeled by considering two separate groundwater infiltration conditions: {open_quotes}wet{close_quotes} with a mean flux of 10 mm/yr, and {open_quotes}dry{close_quotes} with a mean flux of 0.5 mm/yr. Two alternative waste-package designs and two alternative repository areal thermal power densities are investigated. One waste package is a thin-wall container emplaced in a vertical borehole, and the second is a container designed with corrosion-resistant and corrosion-allowance walls emplaced horizontally in the drift. Thermal power loadings of 57 kW/acre (the loading specified in the original repository conceptual design) and 114 kW/acre (a loading chosen to investigate effects of a {open_quotes}hot repository{close_quotes}) are considered. TSPA-93 incorporates significant new detailed process modeling, including two- and three-dimensional modeling of thermal effects, groundwater flow in the saturated-zone aquifers, and gas flow in the unsaturated zone.

Wilson, M.L.; Barnard, R.W.; Barr, G.E.; Dockery, H.A.; Dunn, E.; Eaton, R.R.; Martinez, M.J. [Sandia National Labs., Albuquerque, NM (United States); Gauthier, J.H.; Guerin, D.C.; Lu, N. [and others

1994-04-01

175

Total-system performance assessment for Yucca Mountain - SNL second iteration (TSPA-1993); Volume 1  

SciTech Connect

Sandia National Laboratories has completed the second iteration of the periodic total-system performance assessments (TSPA-93) for the Yucca Mountain Site Characterization Project (YMP). These analyses estimate the future behavior of a potential repository for high-level nuclear waste at the Yucca Mountain, Nevada, site under consideration by the Department of Energy. TSPA-93 builds upon previous efforts by emphasizing YMP concerns relating to site characterization, design, and regulatory compliance. Scenarios describing expected conditions (aqueous and gaseous transport of contaminants) and low-probability events (human-intrusion drilling and volcanic intrusion) are modeled. The hydrologic processes modeled include estimates of the perturbations to ambient conditions caused by heating of the repository resulting from radioactive decay of the waste. Hydrologic parameters and parameter probability distributions have been derived from available site data. Possible future climate changes are modeled by considering two separate groundwater infiltration conditions: {open_quotes}wet{close_quotes} with a mean flux of 10 mm/yr, and {open_quotes}dry{close_quotes} with a mean flux of 0.5 mm/yr. Two alternative waste-package designs and two alternative repository areal thermal power densities are investigated. One waste package is a thin-wall container emplaced in a vertical borehole, and the second is a container designed with corrosion-resistant and corrosion-allowance walls emplaced horizontally in the drift. Thermal power loadings of 57 kW/acre (the loading specified in the original repository conceptual design) and 114 kW/acre (a loading chosen to investigate effects of a {open_quotes}hot repository{close_quotes}) are considered. TSPA-93 incorporates significant new detailed process modeling, including two- and three-dimensional modeling of thermal effects, groundwater flow in the saturated-zone aquifers, and gas flow in the unsaturated zone.

Wilson, M.L.; Gauthier, J.H.; Barnard, R.W.; Barr, G.E.; Dockery, H.A.; Dunn, E.; Eaton, R.R.; Guerin, D.C.; Lu, N.; Martinez, M.J. [and others] [and others

1994-04-01

176

ITERATIVE ALGEBRAS: HOW ITERATIVE ARE THEY?  

Microsoft Academic Search

Iterative algebras, defined by the property that every guarded system of recursive equations has a unique solution, are proved to have a much stronger property: every system of recursive equations has a unique strict solution. Those systems that have a unique solution in every iterative algebra are characterized.

J. AD ´; S. MILIUS; J. VELEBIL

2008-01-01

177

Manufacturing process assumptions used in fuel cell system cost analyses  

Microsoft Academic Search

This paper is a summary of the manufacturing processes used in recent automotive fuel cell system cost analyses funded by the U.S. Department of Energy (DOE). Through these analyses, DOE examines the projected cost of an 80-kW polymer-electrolyte fuel cell system manufactured at a rate of 500,000 systems per year. Directed Technologies Inc. (DTI) and TIAX LLC (TIAX) have been

Jason Marcinkoski; Brian D. James; Jeff A. Kalinoski; Walt Podolski; Thomas Benjamin; John Kopasz

2011-01-01

178

A parallel iterative partitioned coupling analysis system for large-scale acoustic fluid-structure interactions  

NASA Astrophysics Data System (ADS)

In many engineering fields, dynamic response in fluid-structure interaction (FSI) is important, and some of the FSI phenomena are treated as acoustic FSI (AFSI) problems. Dynamic interactions between fluids and structures may change dynamic characteristics of the structure and its response to external excitation parameters such as seismic loading. This paper describes a parallel coupling analysis system for large-scale AFSI problems using iterative partitioned coupling techniques. We employ an open source parallel finite element analysis system called ADVENTURE, which adopts an efficient preconditioned iterative linear algebraic solver. In addition, we have recently developed a parallel coupling tool called ADVENTURE_Coupler to efficiently handle interface variables in various parallel computing environments. We also employ the Broyden method for updating interface variables to attain robust and fast convergence of fixed-point iterations. This paper describes key features of the coupling analysis system developed, and we perform tests to validate its performance for several AFSI problems. The system runs efficiently in a parallel environment, and it is capable of analyzing three-dimensional-complex-shaped structures with more than 20 million degrees-of-freedom (DOFs). Its numerical results also show good agreement with experimental results.

Kataoka, Shunji; Minami, Satsuki; Kawai, Hiroshi; Yamada, Tomonori; Yoshimura, Shinobu

2014-06-01

179

Tritium processing system for the ITER Li/V blanket test module  

SciTech Connect

The purpose of the ITER Blanket Testing Module is to test the operating and performance of candidate blanket concepts under a real fusion environment. To assure fuel self-sufficiency the tritium breeding, recovery and processing have to be demonstrated. The tritium produced in the blanket has to be processed to a purity which can be used for refueling. All these functions need to be accomplished so that the tritium system can be scaled to a commercial fusion power plant from a safety and reliability point of view. This paper summarizes the tritium processing steps, the size of the equipment, power requirements, space requirements, etc. for a self-cooled lithium blanket. This information is needed for the design and layout of the test blanket ancillary system and to assure that the ITER guidelines for remote handling of ancillary equipment can be met.

Sze, D.K.; Hua, T.Q. [Argonne National Lab., IL (United States); Abdou, M.A. [Univ. of California, Los Angeles, CA (United States); Dagher, M.A.; Waganer, L.M.

1997-04-01

180

Achievable rates of MIMO-ISI systems with linear precoding and iterative LMMSE detection  

Microsoft Academic Search

In this paper, we consider the performance analysis of multiple-input multiple-output (MIMO) inter-symbol interference (ISI) systems involving linear-precoding (LP) and iterative linear minimum mean-square error (ILMMSE) detection. The main contribution of this paper is an area theorem to evaluate the achievable rate of the proposed LP-ILMMSE scheme. Based on this area theorem, we further optimize the linear precoder to maximize

Xiaojun Yuan; Li Ping; Aleksandar Kavcic

2011-01-01

181

Recent advances in Lanczos-based iterative methods for nonsymmetric linear systems  

NASA Technical Reports Server (NTRS)

In recent years, there has been a true revival of the nonsymmetric Lanczos method. On the one hand, the possible breakdowns in the classical algorithm are now better understood, and so-called look-ahead variants of the Lanczos process have been developed, which remedy this problem. On the other hand, various new Lanczos-based iterative schemes for solving nonsymmetric linear systems have been proposed. This paper gives a survey of some of these recent developments.

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

1992-01-01

182

LOW COMPLEXITY ITERATIVE RECEIVERS FOR SPACE-TIME BLOCK CODED MC-CDMA DOWNLINK SYSTEMS  

Microsoft Academic Search

Multi-carrier code division multiple access (MC-CDMA) and space-time block coding (STBC) are two promising tech- niques to fulfill the high-speed and spectral efficiency re- quirements of fourth generation mobile communication sys- tems. In this contribution we present an iterative receiver for the downlink of STBC MC-CDMA systems, that aims to mitigate the effects of multiple access interference (MAI) by jointly

Alberto Jimenez Pacheco; Mariano Garc

183

Iterative Multiuser Detection with Soft Interference Cancellation for Multirate MC-CDMA Systems  

Microsoft Academic Search

This paper presents an effective multi-rate multiuser detector (MUD) for the uplink of single-input multiple- output (SIMO) multi-carrier code division multiple access (MC- CDMA) systems. The MUD considered is an iterative receiver which utilizes the soft information to refine the estimation of the interference to enhance the interference cancellation capability. More specifically, users with different transmission rates are classified into

Yung-ping Tu; Wen-hsien Fang; Hoang-yang Lu; Yie-tarng Chen

2008-01-01

184

Iterative interference cancellation for a coded multicarrier frequency-hopping CDMA (MC-FH-CDMA) system  

Microsoft Academic Search

In this paper, we consider a low complexity iterative multiuser receiver for the coded MC-FH-CDMA system, introduced in M. Ebrahimi T.M. and M. Nasiri-Kenari (May 2002). The structure of the proposed receiver consists of a multiuser likelihood calculator (MULC) and a bank of SISO channel decoders one for each active user. Based on the received signal and a priori information

M. Nasiri-Kenari

2003-01-01

185

A new iterative soft decision subcarrier PIC scheme for CI\\/MC-CDMA system  

Microsoft Academic Search

This paper introduces an improved iterative soft decision subcarrier parallel interference cancellation (SDSub-PIC) technique for the carrier interferometry\\/multicarrier code division multiple access (CI\\/MC-CDMA) system that significantly reduces the multiple access interference (MAI) for the desired user. Carrier interferometry (CI) codes are used to minimize the cross-correlation between different users. In this paper, the interference cancellation is done by taking the

Mithun Mukherjee; Preetam Kumar

2010-01-01

186

Iterative Learning Control of Double Servo Valve Controlled Electro Hydraulic Servo System  

Microsoft Academic Search

Aimed at electro-hydraulic servo force control system, according to the nonlinear of electric-hydraulic servo valve, to improve the speed of equivalent valve response, we propose the double electric-hydraulic servo valve parallel control, and two servo valve are controlled by their respective controller, the same signal inputs two controller, every valve controller can adopt different structure and parameters. Iterative control is

Yu Shaojuan; Song Junjun

2011-01-01

187

Zonal-iterative calculation method for radiation heat transfer in cavity systems  

Microsoft Academic Search

The zonal-iterative calculation method for radiation heat transfer is developed for arbitrary number of zones (opaque diffusely-radiating\\u000a and reflecting surfaces). This method is based on transformation of the initial integral equations to equivalent system of\\u000a integral equations with smaller kernel norm. The method provides high accuracy at a small number of the zones. The method\\u000a was used for analysis of

S. P. Rusin

2006-01-01

188

Iterative semiblind multiuser receivers for a space-time block-coded MC-CDMA uplink system  

Microsoft Academic Search

Iterative multiuser detection and space-time coding are two promising techniques to improve the capacity and performance of coded multiuser systems in wireless channels. In this paper, we present iterative multiuser detection schemes for a space-time block-coded multicarrier code-division multiple-access system with multiple transmit and receive antennas. We consider a more general case of an uplink system in the presence of

Padam L. Kafle; Abu B. Sesay

2004-01-01

189

Application of Iterative Time-Reversal for Electromagnetic Wave Focusing in a Wave Chaotic System  

NASA Astrophysics Data System (ADS)

Time-reversal mirrors exploit the time-reversal invariance of the wave equation to achieve spatial and temporal focusing, and they have been shown to be very effective sensors of perturbations to wave chaotic systems. The sensing technique is based on a classical analogue of the Loschmidt echo [1]. However, dissipation results in an imperfect focusing, hence we created a sensing technique employing exponential amplification to overcome this limitation [1,2]. We now apply the technique of iterative time-reversal, which had been demonstrated in a dissipative acoustic system, to an electromagnetic time-reversal mirror, and experimentally demonstrate improved temporal focusing. We also use a numerical model of a network of transmission lines to demonstrate improved focusing by the iterative technique for various degrees and statistical distributions of loss in the system. The application of the iterative technique to improve the performance and practicality of our sensor is explored.[4pt] [1] B. T. Taddese, et al., Appl. Phys. Lett. 95, 114103 (2009).[0pt] [2] B. T. Taddese, et al., J. Appl. Phys. 108, (2010) in press; arXiv:1008.2409.

Taddese, Biniyam; Antonsen, Thomas; Ott, Edward; Anlage, Steven

2011-03-01

190

Analyses of ACPL Thermal/Fluid Conditioning System.  

National Technical Information Service (NTIS)

Results of engineering analyses are reported. Initial computations were made using a modified control transfer function where the systems performance was characterized parametrically using an analytical model. The analytical model was revised to represent...

L. A. Stephen L. H. Usher

1976-01-01

191

Icebreaker Propulsion Systems Feasibility Study. Volume VII. Mission Sensitivity Analyses.  

National Technical Information Service (NTIS)

The results of these analyses, considering both analytical missions and actual requirements identified from other studies, appear to amply reinforce the validity of prior conclusions as to the superior cost effectiveness of nuclear propulsion systems for ...

1967-01-01

192

A design proposal for the ITER ion cyclotron H&CD system  

NASA Astrophysics Data System (ADS)

In ITER, the ion cyclotron heating (ICH) system should routinely and reliably operate at a power level close to the installed power (20 MW) in quasi-continuous operation. The operation will be efficient and reliable only if plasma coupling and absorption of the fast wave on the plasma bulk are optimized, parasitic power losses in the plasma edge minimized, and the RF power flow, from the wave launching structure to the absorption layer, efficiently maintained against the effects of significant load variations. In this paper the ion cyclotron launcher proposed in the ITER Final Design Report (FDR) is briefly reviewed and a number of design changes are proposed, without any modification of the basic layout, in order to simplify construction and maintenance and to improve the performance and reliability of operation.

Bosia, G.; Beaumont, B.; Bremond, S.; Vulliez, K.

2006-07-01

193

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

194

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

SciTech Connect

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

Takahashi, K.; Kajiwara, K.; Oda, Y.; Kasugai, A.; Kobayashi, N.; Sakamoto, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Doane, J.; Olstad, R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Henderson, M. [ITER Organization, CS90 046, 13067 St. Paul lez Durance Cedex (France)

2011-06-15

195

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

PubMed

High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system. PMID:21721690

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

2011-06-01

196

Newton iterative methods for large scale nonlinear systems. Progress report, 1992--1993  

SciTech Connect

Objective is to develop robust, efficient Newton iterative methods for general large scale problems well suited for discretizations of partial differential equations, integral equations, and other continuous problems. A concomitant objective is to develop improved iterative linear algebra methods. We first outline research on Newton iterative methods and then review work on iterative linear algebra methods. (DLC)

Walker, H.F.; Turner, K.

1993-06-01

197

Concept development for the ITER equatorial port visible?infrared wide angle viewing system.  

PubMed

The ITER equatorial port visible?infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R&D topics are outlined. PMID:23127027

Reichle, R; Beaumont, B; Boilson, D; Bouhamou, R; Direz, M-F; Encheva, A; Henderson, M; Huxford, R; Kazarian, F; Lamalle, Ph; Lisgo, S; Mitteau, R; Patel, K M; Pitcher, C S; Pitts, R A; Prakash, A; Raffray, R; Schunke, B; Snipes, J; Diaz, A Suarez; Udintsev, V S; Walker, C; Walsh, M

2012-10-01

198

Operational Experience with the Scattering Matrix Arc Detection System on the JET ITER-Like Antenna  

SciTech Connect

The Scattering Matrix Arc Detection System (SMAD) has been fully deployed on all 4 sets of Resonant Double Loop (RDL), Vacuum Transmission Line (VTL) and Antenna Pressurised Transmission Lines (APTL) of the JET ICRF ITER-Like Antenna (ILA) and this has been indispensable for operating at low (real) T-point impedance values to investigate ELM tolerance. This paper describes the necessity of the SMAD vs VSWR (Voltage Standing Wave Ratio) protection system, SMAD commissioning, problems and a number of typical events detected by the SMAD system during operation on plasma.

Vrancken, M.; Lerche, E.; Dumortier, P.; Durodie, F.; Evrard, M.; Huygen, S.; Ongena, J.; Van Eester, D.; Van Schoor, M.; Vervier, M.; Weynants, R. [LPP/ERM-KMS, Association EURATOM-Belgian State, Brussels (Belgium); Blackman, T.; Graham, M.; Jacquet, P.; Kaye, A.; Mayoral, M.-L.; Nightingale, M. P. S. [EURATOM/UKAEA Fusion Association, Culham Science Center (United Kingdom); Goulding, R. H. [Oak Ridge National Laboratory, Oak Ridge (United States)

2009-11-26

199

Characterisation of the Sub-Harmonic Arc Detection System on JET ITER-Like Antenna  

SciTech Connect

A Sub-Harmonic Arc Detection (SHAD) system has been installed on the transmission lines feeding the JET ICRF ITER-like-Antenna (ILA). Along with the commissioning of SHAD, extensive measurements of the RF field in the transmission lines were carried-out using fast sampling (125 Mb/s) oscilloscopes. The system is described, and the SHAD ability to detect arcs during ILA operation (in particular on ELMy H modes) is discussed. Overall, SHAD proved to be efficient, and in some conditions it can offer extra protection in complement to other arc detection systems.

Jacquet, P.; Blackman, T.; Mayoral, M.-L.; Nightingale, M. [EURATOM/UKAEA Fusion Association, Culham Science Center, Abingdon, OX14 3DB (United Kingdom); Berger-By, G. [Association EURATOM/CEA, IRFM, F-13108 Saint-Paul-lez Durances (France); Bobkov, V. [Max Planck IPP/EURATOM Assoziation, D-85748 Garching (Germany); Durodie, F. [Association EURATOM/Belgium State, LPP-ERM/KMS, B-1000 Brussels (Belgium)

2009-11-26

200

Concept development for the ITER equatorial port visible/infrared wide angle viewing system  

NASA Astrophysics Data System (ADS)

The ITER equatorial port visible/infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R&D topics are outlined.

Reichle, R.; Beaumont, B.; Boilson, D.; Bouhamou, R.; Direz, M.-F.; Encheva, A.; Henderson, M.; Huxford, R.; Kazarian, F.; Lamalle, Ph.; Lisgo, S.; Mitteau, R.; Patel, K. M.; Pitcher, C. S.; Pitts, R. A.; Prakash, A.; Raffray, R.; Schunke, B.; Snipes, J.; Diaz, A. Suarez; Udintsev, V. S.; Walker, C.; Walsh, M.

2012-10-01

201

ITER's Tokamak Cooling Water System and the the Use of ASME Codes to Comply with French Regulations of Nuclear Pressure Equipment  

SciTech Connect

During inductive plasma operation of ITER, fusion power will reach 500 MW with an energy multiplication factor of 10. The heat will be transferred by the Tokamak Cooling Water System (TCWS) to the environment using the secondary cooling system. Plasma operations are inherently safe even under the most severe postulated accident condition a large, in-vessel break that results in a loss-of-coolant accident. A functioning cooling water system is not required to ensure safe shutdown. Even though ITER is inherently safe, TCWS equipment (e.g., heat exchangers, piping, pressurizers) are classified as safety important components. This is because the water is predicted to contain low-levels of radionuclides (e.g., activated corrosion products, tritium) with activity levels high enough to require the design of components to be in accordance with French regulations for nuclear pressure equipment, i.e., the French Order dated 12 December 2005 (ESPN). ESPN has extended the practical application of the methodology established by the Pressure Equipment Directive (97/23/EC) to nuclear pressure equipment, under French Decree 99-1046 dated 13 December 1999, and Order dated 21 December 1999 (ESP). ASME codes and supplementary analyses (e.g., Failure Modes and Effects Analysis) will be used to demonstrate that the TCWS equipment meets these essential safety requirements. TCWS is being designed to provide not only cooling, with a capacity of approximately 1 GW energy removal, but also elevated temperature baking of first-wall/blanket, vacuum vessel, and divertor. Additional TCWS functions include chemical control of water, draining and drying for maintenance, and facilitation of leak detection/localization. The TCWS interfaces with the majority of ITER systems, including the secondary cooling system. U.S. ITER is responsible for design, engineering, and procurement of the TCWS with industry support from an Engineering Services Organization (ESO) (AREVA Federal Services, with support from Northrop Grumman, and OneCIS). ITER International Organization (ITER-IO) is responsible for design oversight and equipment installation in Cadarache, France. TCWS equipment will be fabricated using ASME design codes with quality assurance and oversight by an Agreed Notified Body (approved by the French regulator) that will ensure regulatory compliance. This paper describes the TCWS design and how U.S. ITER and fabricators will use ASME codes to comply with EU Directives and French Orders and Decrees.

Berry, Jan [ORNL; Ferrada, Juan J [ORNL; Curd, Warren [ITER Organization, Saint Paul Lez Durance, France; Dell Orco, Dr. Giovanni [ITER Organization, Saint Paul Lez Durance, France; Barabash, Vladimir [ITER Organization, Saint Paul Lez Durance, France; Kim, Seokho H [ORNL

2011-01-01

202

ITER reference accidents  

Microsoft Academic Search

Reference accidents are selected to envelope possible accident sequences to confirm the adequacy of ITER's safety design. Analyses of ITER reference accidents were carried out starting from postulated initiating events (PIE) to all consequential failures including environmental releases, if any. In case of plasma control malfunctioning, up to 3.3GW of fusion power can be reached transiently, however, no radiological consequence

H.-W. Bartels; A. Poucet; G. Cambi; C. Gordon; M. Gaeta; W. Gulden; T. Honda; M. Iseli; H. Jahn; J. Koonce; O. Kveton; B. Merrill; N. Mitchell; R. L. Moore; D. Petti; S. Polkinghorne; M. T. Porfiri; J. Raeder; G. Saji; E. Stubbe; S. J. Piet; L. Topilski; N. Uckan; W. VanHove

1998-01-01

203

RF Sources for the ITER Ion Cyclotron Heating and Current Drive System  

SciTech Connect

The RF source requirements for the ITER ion cyclotron (IC) heating and current drive system are very challenging ? 20 MW CW power into an antenna load with a VSWR of up to 2 over the frequency range of 35-65 MHz. For the two present antenna designs under consideration, 8 sources providing 2.5 MW each are to be employed. For these sources, the outputs of two final power amplifiers (FPAs), using the high power CPI 4CM2500KG tube, are combined with a 180? hybrid combiner to easily meet the ITER IC source requirements ? 2.5 MW is supplied at a VSWR of 2 at ? 70% of the maximum tube power available in class B operation. The cylindrical cavity configuration for the FPAs is quite compact so that the 8 combined sources fit into the space allocated at the ITER site with room to spare. The source configuration is described in detail and its projected operating power curves are presented. Although the CPI tube has been shown to be stable under high power operating conditions on many facilities, a test of the combined FPA source arrangement is in preparation using existing high power 30 MHz amplifiers to assure that this configuration can be made robustly stable for all phases at a VSWR up to 2. The possibility of using 12 sources to feed a suitably modified antenna design is also discussed in the context of providing flexibility for specifying the final IC antenna design.

Hosea J, Brunkhorst C, Fredd E, Goulding RH, Greenough N, Kung C, Rasmussen DA, Swain DW, Wilson JR

2005-10-04

204

RF Matching Feedback Control Systems on the JET ITER-Like Antenna  

SciTech Connect

Ion Cyclotron Resonance Frequency (ICRF) antennas achieve maximum power transfer from RF generator to plasma load by establishing an impedance match. The JET ITER-Like Antenna (ILA) consists of 4 mutually coupled resonators that need to be matched simultaneously and whose resonant states need to be accurately controlled by several available actuators to couple maximum power and to achieve optimal ELM resilience. The operation of the matching system is described. Experimental operation revealed some phenomena and sensitivities that did not surface from simulation alone and that should be taken into account for the design of future ICRF antennae systems.

Vrancken, M.; Dumortier, P.; Durodie, F.; Huygen, S.; Lerche, E.; Messiaen, A. M.; Ongena, J.; Van Eester, D.; Van Schoor, M.; Vervier, M.; Weynants, R. [LPP/ERM-KMS, Association EURATOM-Belgian State, Brussels (Belgium); Argouarch, A. [Association EURATOM/CEA, CEA Cadarache (France); Blackman, T.; Graham, M.; Jacquet, P.; Mayoral, M.-L.; Nightingale, M. P. S.; Whitehurst, A. [EURATOM/UKAEA Fusion Association, Culham Science Center (United Kingdom); Goulding, R. H. [Oak Ridge National Laboratory, Oak Ridge (United States)

2009-11-26

205

Models Extracted from Text for System-Software Safety Analyses  

NASA Technical Reports Server (NTRS)

This presentation describes extraction and integration of requirements information and safety information in visualizations to support early review of completeness, correctness, and consistency of lengthy and diverse system safety analyses. Software tools have been developed and extended to perform the following tasks: 1) extract model parts and safety information from text in interface requirements documents, failure modes and effects analyses and hazard reports; 2) map and integrate the information to develop system architecture models and visualizations for safety analysts; and 3) provide model output to support virtual system integration testing. This presentation illustrates the methods and products with a rocket motor initiation case.

Malin, Jane T.

2010-01-01

206

Static and Dynamic Performance of Newly Developed ITER Relevant Insulation Systems after Neutron Irradiation  

SciTech Connect

Fiber reinforced plastics will be used as insulation systems for the superconducting magnet coils of ITER. The fast neutron and gamma radiation environment present at the magnet location will lead to serious material degradation, particularly of the insulation. For this reason, advanced radiation-hard resin systems are of special interest. In this study various R-glass fiber / Kapton reinforced DGEBA epoxy and cyanate ester composites fabricated by the vacuum pressure impregnation method were investigated. All systems were irradiated at ambient temperature (340 K) in the TRIGA reactor (Vienna) to a fast neutron fluence of 1x1022 m-2 (E>0.1 MeV). Short-beam shear and static tensile tests were carried out at 77 K prior to and after irradiation. In addition, tension-tension fatigue measurements were used in order to assess the mechanical performance of the insulation systems under the pulsed operation conditions of ITER. For the cyanate ester based system the influence of interleaving Kapton layers on the static and dynamic material behavior was investigated as well.

Prokopec, R.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W. [Atomic Institute of the Austrian Universities, 1020 Vienna (Austria)

2006-03-31

207

An iterative action minimizing method for computing optimal paths in stochastic dynamical systems  

NASA Astrophysics Data System (ADS)

We present a numerical method for computing optimal transition pathways and transition rates in systems of stochastic differential equations (SDEs). In particular, we compute the most probable transition path of stochastic equations by minimizing the effective action in a corresponding deterministic Hamiltonian system. The numerical method presented here involves using an iterative scheme for solving a two-point boundary value problem for the Hamiltonian system. We validate our method by applying it to both continuous stochastic systems, such as nonlinear oscillators governed by the Duffing equation, and finite discrete systems, such as epidemic problems, which are governed by a set of master equations. Furthermore, we demonstrate that this method is capable of dealing with stochastic systems of delay differential equations.

Lindley, Brandon S.; Schwartz, Ira B.

2013-07-01

208

An iterative action minimizing method for computing optimal paths in stochastic dynamical systems  

NASA Astrophysics Data System (ADS)

We present a numerical method for computing optimal transition pathways and transition rates in systems of stochastic differential equations (SDEs). In particular, we compute the most probable transition path of stochastic equations by minimizing the effective action in a corresponding deterministic Hamiltonian system. The numerical method presented here involves using an iterative scheme for solving a two-point boundary value problem for the Hamiltonian system. We validate our method by applying it to both continuous stochastic systems, such as nonlinear oscillators governed by the Duffing equation, and finite discrete systems, such as epidemic problems, which are governed by a set of master equations. Furthermore, we demonstrate that this method is capable of dealing with stochastic systems of delay differential equations.

Lindley, Brandon; Schwartz, Ira

2013-03-01

209

HV-system for CW-gyrotrons at W7-X and the relevance for ITER  

NASA Astrophysics Data System (ADS)

Electron Cyclotron Resonance Heating (ECRH) is the main heating method for the Wendelstein 7-X Stellarator (W7-X), which is under construction at IPP-Greifswald. A 10 MW ECRH plant with CW-capability at 140 GHz is under construction to meet the scientific objectives. The microwave power is generated by 10 gyrotrons with 1 MW each two gyrotrons are operational at IPP in Greifswald. The tubes are equipped with a single-stage depressed collector for energy recovery and operate with an output power modulation between 0.3 and 1 MW with a sinusoidal frequency of up to 10 kHz which is achieved by modulating the depression voltage and is an interesting feature for NTM control at ITER. The general features of the ECRH-plant such as frequency power, cw-capability, flexibility and the experimental experience are of high relevance for the ITER system. Each gyrotron is fed by two high-voltage sources. A high-power supply for driving the electron beam and a precision low-power supply for beam acceleration. The high-power facility consists of modular solid state HV-supplies (-65 kV 50/100 A) providing fast power control and high flexibility. The low-power high-voltage source for beam acceleration is realized by a feed back controlled high-voltage servo-amplifier driving the depression voltage. A protection system with a thyratron crowbar for fast power removal in case of gyrotron failure by arcing is installed. Both the high power and low-power high-voltage sources have the capability to supply a 2 MW ITER gyrotron without any modification. Analogue electronic devices control the fast functions of the high-voltage system for each gyrotron and a hierarchy of industrial standard PLCs and computers supervise the whole ECRH-plant.

Braune, H.; Brand, P.; Krampitz, R.; Leonhardt, W.; Mellein, D.; Michel, G.; Mueller, G.; Sachtleben, J.; Winkler, M.; W7-X ECRH Teams at IPP IPF; FZK

2005-01-01

210

ProVac3D and Application to the Neutral Beam Injection System of ITER  

SciTech Connect

In order to heat the confined plasma up to 100 million degrees Celsius and initiate a sustained fusion reaction, ITER will use several heating mechanisms at the same time, of which Neutral Beam Injection (NBI) systems play an important role. The NBI includes several internal gas sources and has to be operated under vacuum conditions. We have developed ProVac3D, a Monte Carlo simulation code, to calculate gas dynamics and the density profiles in volumes of interest inside NBI. This enables us to elaborate our in-situ and state-of-the-art cryogenic pump design and estimate the corresponding pumping speed.

Luo, X.; Dremel, M.; Day, Ch. [Institute for Technical Physics, Forschungszentrum Karlsruhe GmbH, P.O. Box 3640, 76021 Karlsruhe (Germany)

2008-12-31

211

Thermal mechanical analysis on the ACB-CP valve box of ITER cryogenic system  

NASA Astrophysics Data System (ADS)

ACB-CP is an auxiliary cold box used to distribute and control the cryogenic fluids to cool the cryopumps in ITER cryogenic system. A 3-D structure design is performed as a preliminary design. In order to validate the structure design, the thermal mechanical analysis on the piping must be followed. A 3-D finite element model of ACB-CP is built. The steady state thermal analysis and thermal mechanical coupling analysis of the internal piping are performed. The thermal stress distributions and the maximal thermal stress values are obtained. The results lay the reliable foundation for the design and improvement of ACB-CP.

Tang, Jiancheng; Xiong, Lianyou; Peng, Nan; Jiang, Yongcheng; Liu, Liqiang; Zhang, Liang

2012-06-01

212

A protection system for the JET ITER-like wall based on imaging diagnostics.  

PubMed

The new JET ITER-like wall (made of beryllium and tungsten) is more fragile than the former carbon fiber composite wall and requires active protection to prevent excessive heat loads on the plasma facing components (PFC). Analog CCD cameras operating in the near infrared wavelength are used to measure surface temperature of the PFCs. Region of interest (ROI) analysis is performed in real time and the maximum temperature measured in each ROI is sent to the vessel thermal map. The protection of the ITER-like wall system started in October 2011 and has already successfully led to a safe landing of the plasma when hot spots were observed on the Be main chamber PFCs. Divertor protection is more of a challenge due to dust deposits that often generate false hot spots. In this contribution we describe the camera, data capture and real time processing systems. We discuss the calibration strategy for the temperature measurements with cross validation with thermal IR cameras and bi-color pyrometers. Most importantly, we demonstrate that a protection system based on CCD cameras can work and show examples of hot spot detections that stop the plasma pulse. The limits of such a design and the associated constraints on the operations are also presented. PMID:23130796

Arnoux, G; Devaux, S; Alves, D; Balboa, I; Balorin, C; Balshaw, N; Beldishevski, M; Carvalho, P; Clever, M; Cramp, S; de Pablos, J-L; de la Cal, E; Falie, D; Garcia-Sanchez, P; Felton, R; Gervaise, V; Goodyear, A; Horton, A; Jachmich, S; Huber, A; Jouve, M; Kinna, D; Kruezi, U; Manzanares, A; Martin, V; McCullen, P; Moncada, V; Obrejan, K; Patel, K; Lomas, P J; Neto, A; Rimini, F; Ruset, C; Schweer, B; Sergienko, G; Sieglin, B; Soleto, A; Stamp, M; Stephen, A; Thomas, P D; Valcárcel, D F; Williams, J; Wilson, J; Zastrow, K-D

2012-10-01

213

A protection system for the JET ITER-like wall based on imaging diagnostics  

SciTech Connect

The new JET ITER-like wall (made of beryllium and tungsten) is more fragile than the former carbon fiber composite wall and requires active protection to prevent excessive heat loads on the plasma facing components (PFC). Analog CCD cameras operating in the near infrared wavelength are used to measure surface temperature of the PFCs. Region of interest (ROI) analysis is performed in real time and the maximum temperature measured in each ROI is sent to the vessel thermal map. The protection of the ITER-like wall system started in October 2011 and has already successfully led to a safe landing of the plasma when hot spots were observed on the Be main chamber PFCs. Divertor protection is more of a challenge due to dust deposits that often generate false hot spots. In this contribution we describe the camera, data capture and real time processing systems. We discuss the calibration strategy for the temperature measurements with cross validation with thermal IR cameras and bi-color pyrometers. Most importantly, we demonstrate that a protection system based on CCD cameras can work and show examples of hot spot detections that stop the plasma pulse. The limits of such a design and the associated constraints on the operations are also presented.

Arnoux, G.; Balboa, I.; Balshaw, N.; Beldishevski, M.; Cramp, S.; Felton, R.; Goodyear, A.; Horton, A.; Kinna, D.; McCullen, P.; Obrejan, K.; Patel, K.; Lomas, P. J.; Rimini, F.; Stamp, M.; Stephen, A.; Thomas, P. D.; Williams, J.; Wilson, J.; Zastrow, K.-D. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); and others

2012-10-15

214

A block iterative LU solver for weakly coupled linear systems. [in fluid dynamics equations  

NASA Technical Reports Server (NTRS)

A hybrid technique, called the block iterative LU solver, is proposed for solving the linear equations resulting from a finite element numerical analysis of certain fluid dynamics problems where the equations are weakly coupled between distinct sets of variables. Either the block Jacobi iterative method or the block Gauss-Seidel iterative solver is combined with LU decomposition.

Cooke, C. H.

1977-01-01

215

X-34 Main Propulsion System-Selected Subsystem Analyses  

NASA Technical Reports Server (NTRS)

The X-34 hypersonic flight vehicle is currently under development by Orbital Sciences Corporation (Orbital). The Main Propulsion System (MPS) has been designed around the liquid propellant Fastrac rocket engine currently under development at NASA Marshall Space Flight Center. This paper presents selected analyses of MPS subsystems and components. Topics include the integration of component and system level modeling of the LOX dump subsystem and a simple terminal bubble velocity analysis conducted to guide propellant feed line design.

Brown, T. M.; McDonald, J. P.; Knight, K. C.; Champion, R. H., Jr.

1998-01-01

216

Development of a Twin-Screw D-2 Extruder for the ITER Pellet Injection System  

SciTech Connect

A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. The extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with single-stage gas gun into the plasma. A one-fifth ITER scale prototype extruder has been built to produce a continuous solid deuterium extrusion. Deuterium gas is precooled and liquefied before being introduced into the extruder. The precooler consists of a copper vessel containing liquid nitrogen surrounded by a deuterium gas filled copper coil. The liquefier is comprised of a copper cylinder connected to a Cryomech AL330 cryocooler, which is surrounded by a copper coil that the precooled deuterium flows through. The lower extruder barrel is connected to a Cryomech GB-37 cryocooler to solidify the deuterium (at approximate to 15 K) before it is forced through the extruder nozzle. A viewport located below the extruder nozzle provides a direct view of the extrusion. A camera is used to document the extrusion quality and duration. A data acquisition system records the extruder temperatures, torque, and speed, upstream, and downstream pressures. This paper will describe the prototype twin-screw extruder and initial extrusion results.

Meitner, Steven J [ORNL; Baylor, Larry R [ORNL; Carbajo, Juan J [ORNL; Combs, Stephen Kirk [ORNL; Fehling, Dan T [ORNL; Foust, Charles R [ORNL; McFee, Marshall T [ORNL; McGill, James M [ORNL; Rasmussen, David A [ORNL; Sitterson, R G [ORNL; Sparks, Dennis O [ORNL; Qualls, A L [ORNL

2009-07-01

217

Two-Dimensional Iterative Decoding Schemes for Holographic Data Storage Systems  

NASA Astrophysics Data System (ADS)

Two iterative decoding (ID) schemes, which are the ID using a single parity bit (ID-SPB) and ID using a modulation code (ID-MC), are proposed for holographic data storage systems. In the ID-SPB, a single two-dimensional parity bit is employed to conduct ID, whereas in the ID-MC, the inherent constraint of the modulation code is utilized to conduct ID. In both schemes, a data page is iteratively decoded by exchanging extrinsic information between the horizontal and vertical data bits in the page. In particular, in the ID-SPB, by adding more parity bits to each row and column of the interleaved page, we can conduct the ID within a page as well as between the original and interleaved pages. Thus, additional performance gain can be achieved in the ID-SPB. On the other hand, the ID-MC has a performance gain without loss of data rate since parity bits are not required for ID. The simulation results show that the proposed ID-SPB and ID-MC have about 2--4 and 1--2 dB performance gains in terms of bit error rate compared with the system without ID, respectively.

Kim, Taehyung; Kong, Gyuyeol; Choi, Sooyong

2012-08-01

218

RAMI Analysis for Designing and Optimizing Tokamak Cooling Water System (TCWS) for the ITER's Fusion Reactor  

SciTech Connect

U.S.-ITER is responsible for the design, engineering, and procurement of the Tokamak Cooling Water System (TCWS). TCWS is designed to provide cooling and baking for client systems that include the first wall/blanket, vacuum vessel, divertor, and neutral beam injector. Additional operations that support these primary functions include chemical control of water provided to client systems, draining and drying for maintenance, and leak detection/localization. TCWS interfaces with 27 systems including the secondary cooling system, which rejects this heat to the environment. TCWS transfers heat generated in the Tokamak during nominal pulsed operation - 850 MW at up to 150 C and 4.2 MPa water pressure. Impurities are diffused from in-vessel components and the vacuum vessel by water baking at 200-240 C at up to 4.4 MPa. TCWS is complex because it serves vital functions for four primary clients whose performance is critical to ITER's success and interfaces with more than 20 additional ITER systems. Conceptual design of this one-of-a-kind cooling system has been completed; however, several issues remain that must be resolved before moving to the next stage of the design process. The 2004 baseline design indicated cooling loops that have no fault tolerance for component failures. During plasma operation, each cooling loop relies on a single pump, a single pressurizer, and one heat exchanger. Consequently, failure of any of these would render TCWS inoperable, resulting in plasma shutdown. The application of reliability, availability, maintainability, and inspectability (RAMI) tools during the different stages of TCWS design is crucial for optimization purposes and for maintaining compliance with project requirements. RAMI analysis will indicate appropriate equipment redundancy that provides graceful degradation in the event of an equipment failure. This analysis helps demonstrate that using proven, commercially available equipment is better than using custom-designed equipment with no field experience and lowers specific costs while providing higher reliability. This paper presents a brief description of the TCWS conceptual design and the application of RAMI tools to optimize the design at different stages during the project.

Ferrada, Juan J [ORNL; Reiersen, Wayne T [ORNL

2011-01-01

219

Efficient methodologies for system matrix modelling in iterative image reconstruction for rotating high-resolution PET  

NASA Astrophysics Data System (ADS)

A fully 3D iterative image reconstruction algorithm has been developed for high-resolution PET cameras composed of pixelated scintillator crystal arrays and rotating planar detectors, based on the ordered subsets approach. The associated system matrix is precalculated with Monte Carlo methods that incorporate physical effects not included in analytical models, such as positron range effects and interaction of the incident gammas with the scintillator material. Custom Monte Carlo methodologies have been developed and optimized for modelling of system matrices for fast iterative image reconstruction adapted to specific scanner geometries, without redundant calculations. According to the methodology proposed here, only one-eighth of the voxels within two central transaxial slices need to be modelled in detail. The rest of the system matrix elements can be obtained with the aid of axial symmetries and redundancies, as well as in-plane symmetries within transaxial slices. Sparse matrix techniques for the non-zero system matrix elements are employed, allowing for fast execution of the image reconstruction process. This 3D image reconstruction scheme has been compared in terms of image quality to a 2D fast implementation of the OSEM algorithm combined with Fourier rebinning approaches. This work confirms the superiority of fully 3D OSEM in terms of spatial resolution, contrast recovery and noise reduction as compared to conventional 2D approaches based on rebinning schemes. At the same time it demonstrates that fully 3D methodologies can be efficiently applied to the image reconstruction problem for high-resolution rotational PET cameras by applying accurate pre-calculated system models and taking advantage of the system's symmetries.

Ortuño, J. E.; Kontaxakis, G.; Rubio, J. L.; Guerra, P.; Santos, A.

2010-04-01

220

Transportation systems analyses. Volume 2: Technical/programmatics  

NASA Astrophysics Data System (ADS)

The principal objective of this study is to accomplish a systems engineering assessment of the nation's space transportation infrastructure. This analysis addresses the necessary elements to perform man delivery and return, cargo transfer, cargo delivery, payload servicing, and the exploration of the Moon and Mars. Specific elements analyzed, but not limited to, include the Space Exploration Initiative (SEI), the National Launch System (NLS), the current expendable launch vehicle (ELV) fleet, ground facilities, the Space Station Freedom (SSF), and other civil, military and commercial payloads. The performance of this study entails maintaining a broad perspective on the large number of transportation elements that could potentially comprise the U.S. space infrastructure over the next several decades. To perform this systems evaluation, top-level trade studies are conducted to enhance our understanding of the relationships between elements of the infrastructure. This broad 'infrastructure-level perspective' permits the identification of preferred infrastructures. Sensitivity analyses are performed to assure the credibility and usefulness of study results. This report documents the three principal transportation systems analyses (TSA) efforts during the period 7 November 92 - 6 May 93. The analyses are as follows: Mixed-Fleet (STS/ELV) strategies for SSF resupply; Transportation Systems Data Book - overview; and Operations Cost Model - overview/introduction.

1993-05-01

221

Dual-laser calibration of Thomson scattering systems in ITER and RFX-mod  

NASA Astrophysics Data System (ADS)

We first review the principles of the dual-laser calibration technique for measuring the relative sensitivities of the spectral channels in a Thomson scattering (TS) diagnostic system by detecting with the same spectrometer the spectra scattered by the same plasma volume from two laser pulses of different wavelengths. A new data analysis method is then introduced, based on the minimization of a single ?2 function, that provides a simpler and more convenient way to determine the measurement errors on the calibration coefficients. The new analysis method is used here to investigate the expected performances of this calibration technique in the core LIDAR TS system of ITER currently under design and in the conventional multipoint TS system of RFX-mod. By calculating the expected calibration errors for typical plasma scenarios we discuss the different possible choices of the calibration laser, the characteristics of the calibrating plasma and other system parameters with an impact on the application of the technique. For ITER core LIDAR TS, designed with Nd?:?YAG at 1064 nm as main laser, a ruby laser shows slightly better performances as a calibration laser compared with a second harmonic Nd?:?YAG and a calibration accuracy ?1% can be achieved in a relatively small number of pairs of laser pulses. In RFX-mod the combination of a Nd?:?YAG and a Nd?:?YLF laser systems is the only viable choice, and we find that, in spite of the small difference between the two wavelengths (? = 1064 nm and ? = 1053 nm, respectively), dual-laser calibration is still possible to the required accuracy with an affordable number of pairs of laser shots.

Giudicotti, L.; Pasqualotto, R.

2014-04-01

222

Fast secant methods for the iterative solution of large nonsymmetric linear systems  

NASA Technical Reports Server (NTRS)

A family of secant methods based on general rank-1 updates was revisited in view of the construction of iterative solvers for large non-Hermitian linear systems. As it turns out, both Broyden's good and bad update techniques play a special role, but should be associated with two different line search principles. For Broyden's bad update technique, a minimum residual principle is natural, thus making it theoretically comparable with a series of well known algorithms like GMRES. Broyden's good update technique, however, is shown to be naturally linked with a minimum next correction principle, which asymptotically mimics a minimum error principle. The two minimization principles differ significantly for sufficiently large system dimension. Numerical experiments on discretized partial differential equations of convection diffusion type in 2-D with integral layers give a first impression of the possible power of the derived good Broyden variant.

Deuflhard, Peter; Freund, Roland; Walter, Artur

1990-01-01

223

MHD equilibrium methods for ITER (International Thermonuclear Experimental Reactor) PF (poloidal field) coil design and systems analysis  

SciTech Connect

Two versions of the Fusion Engineering Design Center (FEDC) free-boundary equilibrium code designed to computer the poloidal field (PF) coil current distribution of elongated, magnetically limited tokamak plasmas are demonstrated and applied to the systems analysis of the impact of plasma elongation on the design point of the International Thermonuclear Experimental Reactor (ITER). These notes were presented at the ITER Specialists' Meeting on the PF Coil System and Operational Scenario, held at the Max Planck Institute for Plasma Physics in Garching, Federal Republic of Germany, May 24--27, 1988. 8 refs., 6 figs., 4 tabs.

Strickler, D.J.; Galambos, J.D.; Peng, Y.K.M.

1989-03-01

224

Compartment Venting Analyses of Ares I First Stage Systems Tunnel  

NASA Technical Reports Server (NTRS)

Compartment venting analyses have been performed for the Ares I first stage systems tunnel using both the lumped parameter method and the three-dimensional (31)) transient computational fluid dynamics (CFD) approach. The main objective of venting analyses is to predict the magnitudes of differential pressures across the skin so the integrity of solid walls can be evaluated and properly designed. The lumped parameter method assumes the gas pressure and temperature inside the systems tunnel are spatially uniform, which is questionable since the tunnel is about 1,700 in. long and 4 in. wide. Therefore, 31) transient CFD simulations using the commercial CFD code FLUENT are performed in order to examine the gas pressure and temperature variations inside the tunnel. It was found that the uniform pressure and temperature assumptions inside the systems tunnel are valid during ascent. During reentry, the uniform pressure assumption is also reasonable but the uniform temperature assumption is not valid. Predicted pressure and temperature inside the systems tunnel using CFD are also compared with those from the lumped parameter method using the NASA code CHCHVENT. In general, the average pressure and temperature inside the systems tunnel from CFD are between the burst and crush results from CHCHVENT during both ascent and reentry. The skin differential pressure and pressure inside the systems tunnel relative to freestream pressure from CHCHVENT as well as velocity vectors and streamlines are also discussed in detail.

Wang, Qunzhen; Arner, Stephen

2009-01-01

225

Enhancing the Reflexivity of System Innovation Projects with System Analyses  

ERIC Educational Resources Information Center

Networks aiming for fundamental changes bring together a variety of actors who are part and parcel of a problematic context. These system innovation projects need to be accompanied by a monitoring and evaluation approach that supports and maintains reflexivity to be able to deal with uncertainties and conflicts while challenging current practices…

van Mierlo, Barbara; Arkesteijn, Marlen; Leeuwis, Cees

2010-01-01

226

An alpha particle measurement system using an energetic neutral helium beam in ITER (invited).  

PubMed

An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He(+) ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He(+) ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application. PMID:22380323

Sasao, M; Kisaki, M; Kobuchi, T; Tsumori, K; Tanaka, N; Terai, K; Okamoto, A; Kitajima, S; Kaneko, O; Shinto, K; Wada, M

2012-02-01

227

An alpha particle measurement system using an energetic neutral helium beam in ITER (invited)  

SciTech Connect

An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He{sup +} ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He{sup +} ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application.

Sasao, M.; Tanaka, N.; Terai, K.; Kaneko, O. [Graduate school of Engineering, Tohoku University, Sendai 980-8579 (Japan); Kisaki, M.; Kobuchi, T.; Tsumori, K.; Okamoto, A.; Kitajima, S. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Shinto, K. [IFMIF R and D Center, Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Wada, M. [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

2012-02-15

228

Progress of the ITER equatorial vis/IR wide angle viewing system optical design  

SciTech Connect

The equatorial vis/IR wide angle viewing system is present in four ITER diagnostic equatorial ports. This instrument will cover a large field of view with high spatial and temporal resolutions, to provide real time temperature measurements of plasma facing components, spectral data in the visible range, information on runaway electrons, and pellet tracking. This diagnostic needs to be reliable, precise, and long lasting. Its design is driven by both the tokamak severe environment and the high performances required for machine protection. The preliminary design phase is ongoing. Paramount issues are being tackled, relative to wide spectral band optical design, material choice, and optomechanical difficulties due to the limited space available for this instrument in the ports, since many other diagnostics and services are also present. Recent progress of the diagnostic optical design and status of associated R and D are presented.

Davi, M.; Corre, Y.; Guilhem, D.; Jullien, F.; Reichle, R.; Salasca, S.; Travere, J. M. [Association Euratom CEA, CEA/DSM/IRFM, Cadarache, 13108 Saint-Paul-lez-Durance (France); Cal, E. de la; Manzanares, A.; Pablos, J. L. de [Association Euratom CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Migozzi, J. B. [JBM Optique, 11 Av. de la division Leclerc, 92310 Sevres (France)

2008-10-15

229

Performance of multi-aperture grid extraction systems for an ITER-relevant RF-driven negative hydrogen ion source  

NASA Astrophysics Data System (ADS)

The ITER neutral beam system requires a negative hydrogen ion beam of 48 A with an energy of 0.87 MeV, and a negative deuterium beam of 40 A with an energy of 1 MeV. The beam is extracted from a large ion source of dimension 1.9 × 0.9 m2 by an acceleration system consisting of seven grids with 1280 apertures each. Currently, apertures with a diameter of 14 mm in the first grid are foreseen. In 2007, the IPP RF source was chosen as the ITER reference source due to its reduced maintenance compared with arc-driven sources and the successful development at the BATMAN test facility of being equipped with the small IPP prototype RF source ( {\\sim}\\frac{1}{8} of the area of the ITER NBI source). These results, however, were obtained with an extraction system with 8 mm diameter apertures. This paper reports on the comparison of the source performance at BATMAN of an ITER-relevant extraction system equipped with chamfered apertures with a 14 mm diameter and 8 mm diameter aperture extraction system. The most important result is that there is almost no difference in the achieved current density—being consistent with ion trajectory calculations—and the amount of co-extracted electrons. Furthermore, some aspects of the beam optics of both extraction systems are discussed.

Franzen, P.; Gutser, R.; Fantz, U.; Kraus, W.; Falter, H.; Fröschle, M.; Heinemann, B.; McNeely, P.; Nocentini, R.; Riedl, R.; Stäbler, A.; Wünderlich, D.

2011-07-01

230

Studies on the behaviour of tritium in components and structure materials of tritium confinement and detritiation systems of ITER  

NASA Astrophysics Data System (ADS)

Confinement and the removal of tritium are key subjects for the safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell, tritium is often released as vapour and is in contact with the inner walls. The inner walls of the ITER tritium plant building will also be exposed to tritium in an accident. The tritium released in the buildings is removed by the atmosphere detritiation systems (ADS), where the tritium is oxidized by catalysts and is removed as water. A special gas of SF6 is used in ITER and is expected to be released in an accident such as a fire. Although the SF6 gas has potential as a catalyst poison, the performance of ADS with the existence of SF6 has not been confirmed as yet. Tritiated water is produced in the regeneration process of ADS and is subsequently processed by the ITER water detritiation system (WDS). One of the key components of the WDS is an electrolysis cell. To overcome the issues in a global tritium confinement, a series of experimental studies have been carried out as an ITER R&D task: (1) tritium behaviour in concrete; (2) the effect of SF6 on the performance of ADS and (3) tritium durability of the electrolysis cell of the ITER-WDS. (1) The tritiated water vapour penetrated up to 50 mm into the concrete from the surface in six months' exposure. The penetration rate of tritium in the concrete was thus appreciably first, the isotope exchange capacity of the cement paste plays an important role in tritium trapping and penetration into concrete materials when concrete is exposed to tritiated water vapour. It is required to evaluate the effect of coating on the penetration rate quantitatively from the actual tritium tests. (2) SF6 gas decreased the detritiation factor of ADS. Since the effect of SF6 depends closely on its concentration, the amount of SF6 released into the tritium handling area in an accident should be reduced by some ideas of arrangement of components in the buildings. (3) It was expected that the electrolysis cell of the ITER-WDS could endure 3 years' operation under the ITER design conditions. Measuring the concentration of the fluorine ions could be a promising technique for monitoring the damage to the electrolysis cell.

Kobayashi, K.; Isobe, K.; Iwai, Y.; Hayashi, T.; Shu, W.; Nakamura, H.; Kawamura, Y.; Yamada, M.; Suzuki, T.; Miura, H.; Uzawa, M.; Nishikawa, M.; Yamanishi, T.

2007-12-01

231

Multi-Element Unstructured Analyses of Complex Valve Systems  

NASA Technical Reports Server (NTRS)

The safe and reliable operation of high pressure test stands for rocket engine and component testing places an increased emphasis on the performance of control valves and flow metering devices. In this paper, we will present a series of high fidelity computational analyses of systems ranging from cryogenic control valves and pressure regulator systems to cavitating venturis that are used to support rocket engine and component testing at NASA Stennis Space Center. A generalized multi-element framework with sub-models for grid adaption, grid movement and multi-phase flow dynamics has been used to carry out the simulations. Such a framework provides the flexibility of resolving the structural and functional complexities that are typically associated with valve-based high pressure feed systems and have been difficult to deal with traditional CFD methods. Our simulations revealed a rich variety of flow phenomena such as secondary flow patterns, hydrodynamic instabilities, fluctuating vapor pockets etc. In the paper, we will discuss performance losses related to cryogenic control valves, and provide insight into the physics of the dominant multi-phase fluid transport phenomena that are responsible for the choking like behavior in cryogenic control elements. Additionally, we will provide detailed analyses of the modal instability that is observed in the operation of the dome pressure regulator valve. Such instabilities are usually not localized and manifest themselves as a system wide phenomena leading to an undesirable chatter at high flow conditions.

Sulyma, Peter (Technical Monitor); Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy

2004-01-01

232

The ITER VIS/IR wide angle viewing system: Challenges and on-going R and D  

SciTech Connect

The ITER tokamak is the next generation fusion device which will allow studying burning plasma obtained by a Deuterium-Tritium (D-T) fusion reaction during hundreds of seconds. ITER vacuum vessel real-time protection will be mandatory during plasma operation to avoid water leaks and critical plasma facing components degradation. The protection system will be based on a wide angle viewing system (WAVS) composed with 18 visible (VIS) and 18 infrared (IR) cameras covering 80 % of the vacuum vessel which will be one of the major imaging systems of ITER. Compared to protection systems routinely used on current tokamaks and based on imaging (VIS and/or IR), new constraints must be taken into account because of their influence on the system performance: the harsh environment (high neutron flux) and the metallic plasma facing components (both first wall and divertor). In this new demanding context, we have achieved three mandatory R and D studies starting from the understanding of the source of signals by using realistic photonic simulation up to real-time processing strategy taken into account first order optical design constraints to define what type of performance could be reached for ITER vacuum vessel protection. (authors)

Travere, J. M.; Aumeunier, M. H.; Joanny, M.; Jouve, M.; Martin, V.; Moncada, V.; Salasca, S. [CEA DSM, IRFM, F-13018 Saint Paul-Lez-Durance (France); Marot, L. [Univ. of Basel, Dept. of Physics, CH-4056 Basel (Switzerland); Chabaud, D. [OPTIS, ZE de la Farlede, F-83078 Toulon Cedex 9 (France); Ferme, J. J. [SESO, Pole d'Activite d'Aix en Provence, 305 Rue Louis Armand, F-13792 Aix en Provence Cedex 3 (France); Bremond, F.; Thonnat, M. [INRIA, 2004 route des Lucioles, F-06902 Sophia Antipolis Cedex (France)

2011-07-01

233

Local identification analyses of soils and soil-structure systems  

NASA Astrophysics Data System (ADS)

Geotechnical structures and natural deposits are massive multi-phase particulate systems characterized by the development of localized response mechanisms under extreme loading conditions. A thorough monitoring of the whole response of such massive and distributed soil-systems commonly constitutes a significant challenge and would be prohibitively expensive. Identification and analysis of these systems based on inverse boundary value problem formulations and sparse measurements are generally overly indeterminate. This study presents an alternative inverse problem algorithm to evaluate the local response mechanisms of soil-systems. Point-wise identification analyses of the constitutive behavior of water-saturated geotechnical and geophysical systems are performed using acceleration and pore pressure records provided by a cluster of closely spaced instruments. The developed algorithm consists of: (1) estimation of strain-time histories using the motions recorded by the cluster, (2) evaluation of stress-time histories corresponding to the estimated strains employing a pre-selected class of constitutive models of soil response, (3) computation of accelerations associated with the estimated stresses and recorded pore-water pressures utilizing the equilibrium equations, and (4) evaluation and calibration of an optimal model of soil response by minimizing the discrepancies between recorded and computed accelerations. The developed novel algorithm does not require the availability of boundary condition measurements, or solution of an associated boundary value problem. The constitutive behavior at a specific location of a soil-system is analyzed independently of adjacent response mechanisms or properties. Computer simulations and downhole array records of Lotung (Taiwan) site were used to assess the validity of the proposed technique for level sites and infinite slopes, under conditions of vertical seismic wave propagation. Numerical simulations and centrifuge test data of a quay wall-soil system were employed to demonstrate the capabilities of the developed algorithm in multi-dimensional situations. Results of the identification analyses showed that the proposed technique provides an effective tool to identify local dynamic soil characteristics and properties.

Oskay, Caglar

234

Progress on the ITER electron cyclotron heating and current drive upper launcher steering mirror control system  

Microsoft Academic Search

The ITER ECRH upper launcher (UL) uses a steering mechanism assembly (SMA) to steer the beams in the appropriate location for controlling magnetohydrodynamic (MHD) activity in the plasma (NTMs and sawtooth oscillations). Switching and modulation rotation cycles with an accuracy of 0.1° are requirements for Neoclassical Tearing Modes (NTMs) stabilisation in ITER. Two SMA prototypes have been manufactured. A test

A. Collazos; R. Bertizzolo; R. Chavan; F. Dolizy; F. Felici; T. R. Goodman; J.-D. Landis; F. Sanchez; M. A. Henderson

2009-01-01

235

YALINA analytical benchmark analyses using the deterministic ERANOS code system.  

SciTech Connect

The growing stockpile of nuclear waste constitutes a severe challenge for the mankind for more than hundred thousand years. To reduce the radiotoxicity of the nuclear waste, the Accelerator Driven System (ADS) has been proposed. One of the most important issues of ADSs technology is the choice of the appropriate neutron spectrum for the transmutation of Minor Actinides (MA) and Long Lived Fission Products (LLFP). This report presents the analytical analyses obtained with the deterministic ERANOS code system for the YALINA facility within: (a) the collaboration between Argonne National Laboratory (ANL) of USA and the Joint Institute for Power and Nuclear Research (JIPNR) Sosny of Belarus; and (b) the IAEA coordinated research projects for accelerator driven systems (ADS). This activity is conducted as a part of the Russian Research Reactor Fuel Return (RRRFR) Program and the Global Threat Reduction Initiative (GTRI) of DOE/NNSA.

Gohar, Y.; Aliberti, G.; Nuclear Engineering Division

2009-08-31

236

Evaluation of static mixer flow enhancements for cryogenic viscous compressor prototype for ITER vacuum system  

NASA Astrophysics Data System (ADS)

As part of the U.S. ITER contribution to the vacuum systems for the ITER fusion project, a cryogenic viscous compressor (CVC) is being designed and fabricated to cryopump hydrogenic gases in the torus and neutral beam exhaust streams and to regenerate the collected gases to controlled pressures such that they can be mechanically pumped with controlled flows to the tritium reprocessing facility. One critical element of the CVC design that required additional investigation was the determination of flow rates of the low pressure (up to 1000 Pa) exhaust stream that would allow for complete pumping of hydrogenic gases while permitting trace levels of helium to pass through the CVC to be pumped by conventional vacuum pumps. A sub-scale prototype test facility was utilized to determine the effectiveness of a static mixer pump tube concept, which consisted of a series of rotated twisted elements brazed into a 2-mm thick, 5-cm diameter stainless steel tube. Cold helium gas flow provided by a dewar and helium transfer line was used to cool the exterior of the static mixer pump tube. Deuterium gas was mixed with helium gas through flow controllers at different concentrations while the composition of the exhaust gas was monitored with a Penning gauge and optical spectrometer to determine the effectiveness of the static mixer. It was found that with tube wall temperatures between 6 K and 9 K, the deuterium gas was completely cryopumped and only helium passed through the tube. These results have been used to design the cooling geometry and the static mixer pump tubes in the full-scale CVC prototype.

Duckworth, Robert C.; Baylor, Larry R.; Meitner, Steven J.; Combs, Stephen K.; Ha, Tam; Morrow, Michael; Biewer, T.; Rasmussen, David A.; Hechler, Michael P.; Pearce, Robert J. H.; Dremel, Mattias; Boissin, J.-C.

2014-01-01

237

Evaluation of Static Mixer Flow Enhancements for Cryogenic Viscous Compressor Prototype for ITER Vacuum System  

SciTech Connect

As part of the U.S. ITER contribution to the vacuum systems for the ITER fusion project, a cryogenic viscous compressor (CVC) is being designed and fabricated to cryopump hydrogenic gases in the torus and neutral beam exhaust streams and to regenerate the collected gases to controlled pressures such that they can be mechanically pumped with controlled flows to the tritium reprocessing facility. One critical element of the CVC design that required additional investigation was the determination of flow rates of the low pressure (50 to 1000 Pa) exhaust stream that would allow for complete pumping of hydrogenic gases while permitting trace levels of helium to pass through the CVC to be pumped by conventional vacuum pumps. A sub-scale prototype test facility was utilized to determine the effectiveness of a static mixer pump tube concept, which consisted of a series of rotated twisted elements brazed into a 2-mm thick, 5-cm diameter stainless steel tube. Cold helium gas flow provided by a dewar and helium transfer line was used to cool the exterior of the static mixer pump tube. Deuterium gas was mixed with helium gas through flow controllers at different concentrations while the composition of the exhaust gas was monitored with a Penning gauge and optical spectrometer to determine the effectiveness of the static mixer. It was found that with tube wall temperatures between 6 K and 9 K, the deuterium gas was completely cryopumped and only helium passed through the tube. These results have been used to design the cooling geometry and the static mixer pump tubes in the full-scale CVC prototype

Duckworth, Robert C [ORNL] [ORNL; Baylor, Larry R [ORNL] [ORNL; Meitner, Steven J [ORNL] [ORNL; Combs, Stephen Kirk [ORNL] [ORNL; Ha, Tam T [ORNL] [ORNL; Morrow, Michael [ORNL] [ORNL; Biewer, Theodore M [ORNL] [ORNL; Rasmussen, David A [ORNL] [ORNL; Hechler, Michael P [ORNL] [ORNL; Pearce, R.J.H. [ITER Organization, Cadarache, France] [ITER Organization, Cadarache, France; Dremel, M. [ITER Organization, Cadarache, France] [ITER Organization, Cadarache, France; Boissin, Jean Claude [Consultant] [Consultant

2014-01-01

238

Nuclear systems and testing programs for ITER. Progress report for FY 1998  

SciTech Connect

The effort during this performance period focused on a number of TBWG activities (including test module design and analysis) that were identified and agreed upon (in the presence of the ITER Director and Deputy Director) at TBWG-4. These include: (a) DEMO test module design and performance analysis under pulsed operation; (b) Test program operation plan; (c) Test port design and analysis; (d) Decay heat calculations and safety analysis; (e) Further discussion among the parties to define collaboratory on R and D for the test program as well as possible collaboration on the construction and operation of test articles; (f) Remote handling and ancillary equipment; (g) Criteria for qualifying a blanket module or submodule for actual insertion and testing in ITER; (h) Definition of test module instrumentation and verification of capability to perform in the ITER fusion environment (magnetic field, radiation, heating, etc.); and (i) Analysis to show that the results to be obtained from the test modules as designed can be extrapolated to DEMO and reactor conditions (e.g., higher wall loads and the need to demonstrate tritium self-sufficiency). The main achievements during this performance period include: (1) updating and finalizing the US DDDs for the ITER Blanket Program to form part of the ITER Final Design Report (FDR). Specific revisions were in response to the minimal lithium volume test blanket design requirements and safety impact and (2) evaluating the feasibility of the US test program, including instrumentation and the benefits of the ITER test program. Details of this assessment, including solid breeder and liquid breeder blanket test plans, are documented in UCLA-IFNT-13 (attached). In addition, dose mapping calculations were performed for the ITER Building, including equipment and layout of coolant pipes/heat exchangers. A report on ITER Building dose calculations was sent to UD ITER management and to the Garching Task Coordinator in April, 1998. The report entitled Three-Dimensional Calculations of ITER Building Dose Rate Profiles and Assessment of Accessibility Inside the Building During Operation and After Shutdown of ITER can be located through ITER Reference Number of ITER Task S 62 TD 12, ID No: D325 ITER/US/98/S62TD12-D325 UCLA-FNT-100 UCLA-ENG-98-190.

NONE

1998-12-31

239

An Iterative Approach to the Power Control Problem in Multi-Service CDMA Systems: Distributed Algorithms and their Convergence  

Microsoft Academic Search

In this paper we present two decentralized Iterative Power Control Algorithms (IPCAs) for the uplink and downlink communication in multi-service CDMA wireless environments in order to expand the system capacity while at the same time satisfy the various QoS requirements. The proposed dynamic IPCAs are decentralised in the sense that they can be implemented in a distributed mode at the

G. V. Kotsakis; Symeon Papavassiliou

2002-01-01

240

Jointly gaussian approximation and multi-stage LLR combining in the iterative receiver for MIMO-BICM systems  

Microsoft Academic Search

In this letter, we propose a new multi-stage LLR combining (MLC) algorithm in an iterative receiver for MIMOBICM systems. This algorithm combines the soft information from different receive antennas in a multi-stage fashion, where the combining factors are derived based on the joint likelihood function of bivariate Gaussian random variables. The variance transfer (VT) function of the proposed scheme is

Tao Yang; Jinhong Yuan; Zhenning Shi

2008-01-01

241

Convergence Analysis and Numerical Study of a Fixed-Point Iterative Method for Solving Systems of Nonlinear Equations  

PubMed Central

We present a fixed-point iterative method for solving systems of nonlinear equations. The convergence theorem of the proposed method is proved under suitable conditions. In addition, some numerical results are also reported in the paper, which confirm the good theoretical properties of our approach.

Huang, Na

2014-01-01

242

Adapting iterative algorithms for solving large sparse linear systems for efficient use on the CDC CYBER 205  

NASA Technical Reports Server (NTRS)

Adapting and designing mathematical software to achieve optimum performance on the CYBER 205 is discussed. Comments and observations are made in light of recent work done on modifying the ITPACK software package and on writing new software for vector supercomputers. The goal was to develop very efficient vector algorithms and software for solving large sparse linear systems using iterative methods.

Kincaid, D. R.; Young, D. M.

1984-01-01

243

The variational iteration method: A highly promising method for solving the system of integro-differential equations  

Microsoft Academic Search

This paper applies He’s variational iteration method for solving two systems of Volterra integro-differential equations. The solution process is illustrated and various physically relevant results are obtained. Comparison of the obtained results with exact solutions shows that the used method is an effective and highly promising method for various classes of both linear and nonlinear integro-differential equations.

Jafar Saberi-Nadjafi; Mohamadreza Tamamgar

2008-01-01

244

Advanced vehicle systems assessment. Volume 4: Supporting analyses  

NASA Technical Reports Server (NTRS)

Volume 4 (Supporting Analyses) is part of a five-volume report, Advanced Vehicle Systems Assessment. Thirty-nine individuals, knowledgeable in advanced technology, were interviewed to obtain their preferences. Rankings were calculated for the eight groups they represented, using multiplicative and additive utility models. The four topics for consideration were: (1) preferred range for various battery technologies; (2) preferred battery technology for each of a variety of travel ranges; (3) most promising battery technology, vehicle range combination; and (4) comparison of the most preferred electric vehicle with the methanol-fuled, spark-ignition engine vehicle and with the most preferred of the hybrid vehicles.

Hardy, K.

1985-01-01

245

Design of Electron Cyclotron Heating and Current Drive System of ITER  

NASA Astrophysics Data System (ADS)

Since the end of EDA, the design of the Electron Cyclotron Heating and Current Drive (ECH&CD) system has been modified to respond to progress in physics understanding and change of interface conditions. Nominal RF power of 20 MW is shared by four upper launchers or one equatorial launcher RF beams are steered by front steering mirrors providing wide sweeping angle for the RF beam. DC high voltage power supply may be composed of IGBT pulse step modulators because of high frequency modulation and design flexibility to three different types of 170 GHz gyrotrons provided by three parties. The RF power from the 170 GHz gyrotron is transmitted to the launcher by 63.5 mm? corrugated waveguide line and remotely switched by a waveguide switch between the upper launcher and the equatorial launcher. The ECH&CD system has also a start-up sub-system for assist of initial discharge composed of three 127.5 GHz gyrotrons and a dedicated DC high voltage power supply. Three of transmission lines are shared between 170 GHz gyrotron and 127.5 GHz gyrotron so as to inject RF beam for the start-up through the equatorial launcher. R&Ds of components for high power long pulse and mirror steering mechanism have been on-going in the parties to establish a reliable ITER ECH&CD system.

Kobayashi, N.; Bigelow, T.; Bonicelli, T.; Cirant, S.; Denisov, G.; Heidinger, R.; Henderson, M.; Hogge, J.-P.; Piosczyk, B.; Ramponi, G.; Rao, S. L.; Rasmussen, D.; Saibene, G.; Sakamoto, K.; Takahashi, K.; Temkin, R. J.; Thumm, M.; Tran, M. Q.; Verhoeven, A. G. A.; Zohm, H.

2007-09-01

246

Design of Electron Cyclotron Heating and Current Drive System of ITER  

SciTech Connect

Since the end of EDA, the design of the Electron Cyclotron Heating and Current Drive (ECH and CD) system has been modified to respond to progress in physics understanding and change of interface conditions. Nominal RF power of 20 MW is shared by four upper launchers or one equatorial launcher RF beams are steered by front steering mirrors providing wide sweeping angle for the RF beam. DC high voltage power supply may be composed of IGBT pulse step modulators because of high frequency modulation and design flexibility to three different types of 170 GHz gyrotrons provided by three parties. The RF power from the 170 GHz gyrotron is transmitted to the launcher by 63.5 mm{phi} corrugated waveguide line and remotely switched by a waveguide switch between the upper launcher and the equatorial launcher. The ECH and CD system has also a start-up sub-system for assist of initial discharge composed of three 127.5 GHz gyrotrons and a dedicated DC high voltage power supply. Three of transmission lines are shared between 170 GHz gyrotron and 127.5 GHz gyrotron so as to inject RF beam for the start-up through the equatorial launcher. R and Ds of components for high power long pulse and mirror steering mechanism have been on-going in the parties to establish a reliable ITER ECH and CD system.

Kobayashi, N. [ITER, Cadarache (France); Bigelow, T.; Rasmussen, D. [ORNL, Oak Ridge (United States); Bonicelli, T.; Ramponi, G.; Saibene, G. [EFDA, Garching (Germany); Cirant, S. [ENEA-CNR, Milan (Italy); Denisov, G. [IAP, Nizhny Novgorod (Russian Federation); Heidinger, R.; Piosczyk, B. [FZK, Karlsruhe (Germany); Henderson, M.; Hogge, J.-P.; Thumm, M.; Tran, M. Q. [CRPP, Lausanne (Switzerland); Rao, S. L. [IPR, Bhat (India); Sakamoto, K.; Takahashi, K. [JAEA, Naka (Japan); Temkin, R. J. [MIT PSFC, Cambridge (United States); Verhoeven, A. G. A. [FOM IPP, Rijnhuizen (Netherlands); Zohm, H. [MPI IPP, Garching (Germany)

2007-09-28

247

GoldenBraid: An Iterative Cloning System for Standardized Assembly of Reusable Genetic Modules  

PubMed Central

Synthetic Biology requires efficient and versatile DNA assembly systems to facilitate the building of new genetic modules/pathways from basic DNA parts in a standardized way. Here we present GoldenBraid (GB), a standardized assembly system based on type IIS restriction enzymes that allows the indefinite growth of reusable gene modules made of standardized DNA pieces. The GB system consists of a set of four destination plasmids (pDGBs) designed to incorporate multipartite assemblies made of standard DNA parts and to combine them binarily to build increasingly complex multigene constructs. The relative position of type IIS restriction sites inside pDGB vectors introduces a double loop (“braid”) topology in the cloning strategy that allows the indefinite growth of composite parts through the succession of iterative assembling steps, while the overall simplicity of the system is maintained. We propose the use of GoldenBraid as an assembly standard for Plant Synthetic Biology. For this purpose we have GB-adapted a set of binary plasmids for A. tumefaciens-mediated plant transformation. Fast GB-engineering of several multigene T-DNAs, including two alternative modules made of five reusable devices each, and comprising a total of 19 basic parts are also described.

Sarrion-Perdigones, Alejandro; Falconi, Erica Elvira; Zandalinas, Sara I.; Juarez, Paloma; Fernandez-del-Carmen, Asun; Granell, Antonio; Orzaez, Diego

2011-01-01

248

A policy iteration approach to online optimal control of continuous-time constrained-input systems.  

PubMed

This paper is an effort towards developing an online learning algorithm to find the optimal control solution for continuous-time (CT) systems subject to input constraints. The proposed method is based on the policy iteration (PI) technique which has recently evolved as a major technique for solving optimal control problems. Although a number of online PI algorithms have been developed for CT systems, none of them take into account the input constraints caused by actuator saturation. In practice, however, ignoring these constraints leads to performance degradation or even system instability. In this paper, to deal with the input constraints, a suitable nonquadratic functional is employed to encode the constraints into the optimization formulation. Then, the proposed PI algorithm is implemented on an actor-critic structure to solve the Hamilton-Jacobi-Bellman (HJB) equation associated with this nonquadratic cost functional in an online fashion. That is, two coupled neural network (NN) approximators, namely an actor and a critic are tuned online and simultaneously for approximating the associated HJB solution and computing the optimal control policy. The critic is used to evaluate the cost associated with the current policy, while the actor is used to find an improved policy based on information provided by the critic. Convergence to a close approximation of the HJB solution as well as stability of the proposed feedback control law are shown. Simulation results of the proposed method on a nonlinear CT system illustrate the effectiveness of the proposed approach. PMID:23706414

Modares, Hamidreza; Naghibi Sistani, Mohammad-Bagher; Lewis, Frank L

2013-09-01

249

Safety Issues and Approach to Meet the Safety Requirements in Tokamak Cooling Water System of ITER  

SciTech Connect

The ITER (Latin for 'the way') tokamak cooling water system (TCWS) consists of several separate systems to cool the major ITER components - the divertor/limiter, the first wall blanket, the neutral beam injector and the vacuum vessel. The ex-vessel part of the TCWS systems provides a confinement function for tritium and activated corrosion products in the cooling water. The Vacuum Vessel System also has a functional safety requirement regarding the residual heat removal from in-vessel components. A preliminary hazards assessment (PHA) was performed for a better understanding of the hazards, initiating events, and defense in depth mechanisms associated with the TCWS. The PHA was completed using the following steps. (1) Hazard Identification. Hazards associated with the TCWS were identified including radiological/chemical/electromagnetic hazards and physical hazards (e.g., high voltage, high pressure, high temperature, falling objects). (2) Hazard Categorization. Hazards identified in step (1) were categorized as to their potential for harm to the workers, the public, and/or the environment. (3) Hazard Evaluation. The design was examined to determine initiating events that might occur and that could expose the public, environment, or workers to the hazard. In addition the system was examined to identify barriers that prevent exposure. Finally, consequences to the public or workers were qualitatively assessed, should the initiating event occur and one or more of the barriers fail. Frequency of occurrence of the initiating event and subsequent barrier failure was qualitatively estimated. (4) Accident Analysis. A preliminary hazards analysis was performed on the conceptual design of the TCWS. As the design progresses, a detailed accident analysis will be performed in the form of a failure modes and effects analysis. The results of the PHA indicated that the principal hazards associated with the TCWS were those associated with radiation. These were low compared to hazards associated with nuclear fission reactors and were limited to potential exposure to the on-site workers if appropriate protective actions were not used. However, the risk to the general public off-site was found to be negligible even under worst case accident conditions.

Flanagan, George F [ORNL; Reyes, Susana [ITER Organization, Saint Paul Lez Durance, France; Chang, Keun Pack [ITER Organization, Saint Paul Lez Durance, France; Berry, Jan [ORNL; Kim, Seokho H [ORNL

2010-01-01

250

Appropriate time scales for nonlinear analyses of deterministic jump systems  

NASA Astrophysics Data System (ADS)

In the real world, there are many phenomena that are derived from deterministic systems but which fluctuate with nonuniform time intervals. This paper discusses the appropriate time scales that can be applied to such systems to analyze their properties. The financial markets are an example of such systems wherein price movements fluctuate with nonuniform time intervals. However, it is common to apply uniform time scales such as 1-min data and 1-h data to study price movements. This paper examines the validity of such time scales by using surrogate data tests to ascertain whether the deterministic properties of the original system can be identified from uniform sampled data. The results show that uniform time samplings are often inappropriate for nonlinear analyses. However, for other systems such as neural spikes and Internet traffic packets, which produce similar outputs, uniform time samplings are quite effective in extracting the system properties. Nevertheless, uniform samplings often generate overlapping data, which can cause false rejections of surrogate data tests.

Suzuki, Tomoya

2011-06-01

251

Unsteady Analyses of Valve Systems in Rocket Engine Testing Environments  

NASA Technical Reports Server (NTRS)

This paper discusses simulation technology used to support the testing of rocket propulsion systems by performing high fidelity analyses of feed system components. A generalized multi-element framework has been used to perform simulations of control valve systems. This framework provides the flexibility to resolve the structural and functional complexities typically associated with valve-based high pressure feed systems that are difficult to deal with using traditional Computational Fluid Dynamics (CFD) methods. In order to validate this framework for control valve systems, results are presented for simulations of a cryogenic control valve at various plug settings and compared to both experimental data and simulation results obtained at NASA Stennis Space Center. A detailed unsteady analysis has also been performed for a pressure regulator type control valve used to support rocket engine and component testing at Stennis Space Center. The transient simulation captures the onset of a modal instability that has been observed in the operation of the valve. A discussion of the flow physics responsible for the instability and a prediction of the dominant modes associated with the fluctuations is presented.

Shipman, Jeremy; Hosangadi, Ashvin; Ahuja, Vineet

2004-01-01

252

Subspace Iteration Method for Complex Eigenvalue Problems with Nonsymmetric Matrices in Aeroelastic System  

NASA Technical Reports Server (NTRS)

Modern airplane design is a multidisciplinary task which combines several disciplines such as structures, aerodynamics, flight controls, and sometimes heat transfer. Historically, analytical and experimental investigations concerning the interaction of the elastic airframe with aerodynamic and in retia loads have been conducted during the design phase to determine the existence of aeroelastic instabilities, so called flutter .With the advent and increased usage of flight control systems, there is also a likelihood of instabilities caused by the interaction of the flight control system and the aeroelastic response of the airplane, known as aeroservoelastic instabilities. An in -house code MPASES (Ref. 1), modified from PASES (Ref. 2), is a general purpose digital computer program for the analysis of the closed-loop stability problem. This program used subroutines given in the International Mathematical and Statistical Library (IMSL) (Ref. 3) to compute all of the real and/or complex conjugate pairs of eigenvalues of the Hessenberg matrix. For high fidelity configuration, these aeroelastic system matrices are large and compute all eigenvalues will be time consuming. A subspace iteration method (Ref. 4) for complex eigenvalues problems with nonsymmetric matrices has been formulated and incorporated into the modified program for aeroservoelastic stability (MPASES code). Subspace iteration method only solve for the lowest p eigenvalues and corresponding eigenvectors for aeroelastic and aeroservoelastic analysis. In general, the selection of p is ranging from 10 for wing flutter analysis to 50 for an entire aircraft flutter analysis. The application of this newly incorporated code is an experiment known as the Aerostructures Test Wing (ATW) which was designed by the National Aeronautic and Space Administration (NASA) Dryden Flight Research Center, Edwards, California to research aeroelastic instabilities. Specifically, this experiment was used to study an instability known as flutter. ATW was a small-scale airplane wing comprised of an airfoil and wing tip boom. This wing was formulated based on a NACA-65A004 airfoil shape with a 3.28 aspect ratio. The wing had a span of 18 inch with root chord length of 13.2 inch and tip chord length of 8.7 inch. The total area of this wing was 197 square inch. The wing tip boom was a 1 inch diameter hollow tube of length 21.5 inch. The total weight of the wing was 2.66 lbs.

Pak, Chan-gi; Lung, Shu

2009-01-01

253

An ITER-relevant evacuated waveguide transmission system for the JET-EP ECRH project  

NASA Astrophysics Data System (ADS)

An over-moded evacuated waveguide line was chosen for use in the transmission system for the proposed JET-enhanced performance project (JET-EP) electron cyclotron resonance heating (ECRH) system. A comparison between the quasi-optical, atmospheric waveguide and evacuated waveguide systems was performed for the project with a strong emphasis placed on the technical and financial aspects. The evacuated waveguide line was chosen as the optimal system in light of the above criteria. The system includes six lines of 63.5 mm waveguide for transmitting 6.0 MW(10 s) at 113.3 GHz from the gyrotrons to the launching antenna. The designed lines are on average 72 m in length and consist of nine mitre bends, for an estimated transmission efficiency of ~90%. Each line is designed to include an evacuated switch leading to a calorimetric load, two dc breaks, two gate valves, one pumpout tee, a power monitor mitre bend and a double-disc CVD window near the torus. The location of waveguide support is positioned to minimize the power converted to higher-order modes from waveguide sagging and misalignment. The two gate valves and CVD window are designed to be used as tritium barriers at the torus and between the J1T and J1D buildings. The last leg of the waveguide leading to the torus has to be designed to accommodate the torus movement during disruptions and thermal cycles. All lines are also designed to be compatible with the ITER ECRH system operating at 170 GHz.

Henderson, M. A.; Alberti, S.; Bird, J.; Doane, J.; Elzendoorn, B.; Flemming, C.; Goodman, T. P.; Hoekzema, F.; Hogge, J. P.; MacMillan, G.; Magnin, J. C.; Pioscyk, B.; Porte, L.; Tran, M. Q.; Verhoeven, A. G. A.

2003-11-01

254

Wall conditioning on ITER  

NASA Astrophysics Data System (ADS)

Like all tokamaks, ITER will require wall conditioning systems and strategies for successful operation from the point of view of plasma-facing surface preparation. Unlike today's devices however, ITER will have to manage large quantities of tritium fuel, imposing on wall conditioning a major responsibility for tritium inventory control. It will also feature the largest plasma-facing beryllium surface ever used in a tokamak and its high duty cycle and long pulse are expected to lead to the rapid formation of deposited layers in which tritium can accumulate. This paper summarises the currently planned ITER wall conditioning systems and describes the strategy for their use throughout exploitation of the device.

Shimada, Michiya; Pitts, Richard A.

2011-08-01

255

ITER Ion Cyclotron Transmission Line and Tuning System Design Options and Choices  

NASA Astrophysics Data System (ADS)

The ITER ion cyclotron system is required to deliver 20 MW of power to the plasma for ion heating and for current drive over the 40- to 55-MHz frequency range. An externally tuned antenna module consisting of an array of 24 (4 toroidal x 6 poloidal) current straps is mounted in an equatorial port. The straps are connected (internal to the antenna) in upper and lower poloidal triplets. Eight rf sources are connected to the transmission line and tuning/decoupling system and then to the feeds for the triplets. Two external tuning options that will permit ICH operation with ELMy H-modes are under consideration. In one option, conjugate-T, plasma load resilient, circuits are connected to triplet pairs. The conjugate-T matching components are external to but near the antenna. An alternate design uses a series of combiner-splitters (ELM dumps) to protect the rf sources from reflected power from transient plasma load variations. This talk will describe the design options, evolution of the different designs, and the pros and cons of the options. Future design work and R&D will be needed and will be described. Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725.

Swain, D. W.; Goulding, R. H.; Rasmussen, D. A.

2007-11-01

256

Experimental proof of a load resilient external matching solution for the ITER ICRH system  

SciTech Connect

A reliable load resilient external matching scheme for the ITER ICRH system has been successfully tested on the mock-up of the external matching system with variable plasma load simulation. To avoid the deleterious mutual coupling effects the power has been passively distributed among the upper half and the bottom half of the 24 radiating straps of the antenna plug. In this plug the straps are grouped in 8 triplets by 4-ports junctions. The 4 top and 4 bottom triplets are respectively put in parallel outside the antenna plug near a voltage anti-node by means of T junctions. The load resilient matching is then obtained by a 4 parameters single 'conjugate T' (CT) configuration. For an antenna loading variation of about 1 to 8 {omega}/m the VSWR at the power source remains below 1.3. The maximum voltage along the line remains equal to the one in the antenna plug and there is a fair power share between the straps. A {pi}0{pi}0 toroidal phasing is easily obtained. The poloidal phasing between the top and bottom triplets is determined by the loading. A straightforward matching procedure is described. Good load resilience is also obtained by replacing the CT by one hybrid.

Vervier, M.; Messiaen, A.; Dumortier, P.; Lamalle, P. [LPP-ERM/KMS, EURATOM-Belgian State Association, Trilateral Euregio Cluster, B-1000 Brussels (Belgium)

2005-09-26

257

Automation and Iteration Methods for Processing CCD Stellar Photometry in the Strömvil System  

NASA Astrophysics Data System (ADS)

We have been making CCD observations on stellar fields with use of the Strömvil and Vilnius Photometric Systems at VATT, Mt. Graham; Casleo; USNO-Flagstaff, and Loiano, Italy. From quality photometry of one to two percent accuracy the classification of all the types of stars can be made. We will present our application of the CommandLog (Janusz and Boyle, 2003, The Journal of Astronomical Data, 9, 4) and then show methods for iterating the processing by use of the SIMPLEX algorithm. The CommandLog is an HTML document that provides the photometry cookbook steps to be pasted into the IRAF command line. SIMPLEX code incorporated into our IRAF task allows quick reprocessing of the data to minimalize the errors of the flatfield or tune IRAF photometric parameters in order to obtain the optimum stellar photometry both in the instrumental and transformed standard systems. In July 2004, a Strömvil workshop was held at Castel Gandolfo, Italy. Philip was able to work with the creator of the CommandLog, Janusz, on some CCD data obtained at CASLEO with Olga Pintado. Using SIMPLEX it was possible to investigate many different variations of the input parameters to use in reducing the data. Without SIMPLEX this process would have taken many days of work but we were able to do a set of variations in a few hours.

Boyle, R. P.; Janusz, R.; Philip, A. G. D.; Laugalys, V.

2004-12-01

258

Large and powerful rf-driven hydrogen plasmas: negative ions for the heating systems of ITER  

NASA Astrophysics Data System (ADS)

Negative ion sources are an excellent example for the manifold of applications of low temperature plasmas which ranges from basic research to industrial applications. One of the outstanding application areas is in fusion, where a large and powerful negative hydrogen ion source is as a central component of the neutral beam injection systems for heating and current drive of the international fusion project ITER. The challenge to extract an ion current of 57 A (D) and 69 A (H) from a low temperature hydrogen plasma at low pressure (0.3 Pa) is accompanied by the challenge to accelerate the beam to 1 MeV. Large RF sources with the size of a door operating at a power of up to 800 kW must deliver a uniform and stable negative hydrogen ion current density higher than 200 A/m^2 over the total area for one hour. Simultaneously, the amount of co-extracted electrons should be kept below one in order to avoid severe damages of the extraction system. These requirements can be met only by combining the disciplines of low temperature plasma physics, plasma surface interaction, ion beam optics, beam physics, and mechanical and electrical engineering. The state of the art and prospects of the negative hydrogen ion source development will be discussed with emphasis on the physical aspects.

Fantz, Ursel

2012-10-01

259

Synthesis of trigeneration systems: sensitivity analyses and resilience.  

PubMed

This paper presents sensitivity and resilience analyses for a trigeneration system designed for a hospital. The following information is utilized to formulate an integer linear programming model: (1) energy service demands of the hospital, (2) technical and economical characteristics of the potential technologies for installation, (3) prices of the available utilities interchanged, and (4) financial parameters of the project. The solution of the model, minimizing the annual total cost, provides the optimal configuration of the system (technologies installed and number of pieces of equipment) and the optimal operation mode (operational load of equipment, interchange of utilities with the environment, convenience of wasting cogenerated heat, etc.) at each temporal interval defining the demand. The broad range of technical, economic, and institutional uncertainties throughout the life cycle of energy supply systems for buildings makes it necessary to delve more deeply into the fundamental properties of resilient systems: feasibility, flexibility and robustness. The resilience of the obtained solution is tested by varying, within reasonable limits, selected parameters: energy demand, amortization and maintenance factor, natural gas price, self-consumption of electricity, and time-of-delivery feed-in tariffs. PMID:24453881

Carvalho, Monica; Lozano, Miguel A; Ramos, José; Serra, Luis M

2013-01-01

260

Qualification of the U.S.Made Conductors for ITER Toroidal Field (TF) Magnet System  

Microsoft Academic Search

The U.S. Domestic Agency (USDA) is one of six suppliers of the TF conductor for ITER. To ensure that U.S.-made conductors are in compliance with ITER requirements, we prepared several lengths of the Cable-in-Conduit Conductors (CICC) and short samples for testing in the SULTAN facility in CRPP, Switzerland. We also fully characterized the strands that were used in these SULTAN

N. N. Martovetsky; D. R. Hatfield; J. R. Miller; P. Bruzzone; B. Stepanov; B. Seber

2010-01-01

261

Qualification of the US Made Conductors for ITER TF Magnet System  

SciTech Connect

The US Domestic Agency (USDA) is one of the six suppliers of the TF conductor for ITER. In order to qualify conductors according to ITER requirements we prepared several lengths of the CICC and short samples for testing in the SULTAN facility in CRPP, Switzerland. We also fully characterized the strands that were used in these SULTAN samples. Fabrication experience and test results are presented and discussed.

Martovetsky, Nicolai N [ORNL] [ORNL; Hatfield, Daniel R [ORNL] [ORNL; Miller, John R [ORNL] [ORNL; Bruzzone, P. [CRPP, Switzerland] [CRPP, Switzerland; Stepanov, B. [CRPP, Switzerland] [CRPP, Switzerland; Seber, B. [University of Geneva] [University of Geneva

2010-01-01

262

Reproducible analyses of microbial food for advanced life support systems  

NASA Technical Reports Server (NTRS)

The use of yeasts in controlled ecological life support systems (CELSS) for microbial food regeneration in space required the accurate and reproducible analysis of intracellular carbohydrate and protein levels. The reproducible analysis of glycogen was a key element in estimating overall content of edibles in candidate yeast strains. Typical analytical methods for estimating glycogen in Saccharomyces were not found to be entirely aplicable to other candidate strains. Rigorous cell lysis coupled with acid/base fractionation followed by specific enzymatic glycogen analyses were required to obtain accurate results in two strains of Candida. A profile of edible fractions of these strains was then determined. The suitability of yeasts as food sources in CELSS food production processes is discussed.

Petersen, Gene R.

1988-01-01

263

Maximum Likelihood-Based Iterated Divided Difference Filter for Nonlinear Systems from Discrete Noisy Measurements  

PubMed Central

A new filter named the maximum likelihood-based iterated divided difference filter (MLIDDF) is developed to improve the low state estimation accuracy of nonlinear state estimation due to large initial estimation errors and nonlinearity of measurement equations. The MLIDDF algorithm is derivative-free and implemented only by calculating the functional evaluations. The MLIDDF algorithm involves the use of the iteration measurement update and the current measurement, and the iteration termination criterion based on maximum likelihood is introduced in the measurement update step, so the MLIDDF is guaranteed to produce a sequence estimate that moves up the maximum likelihood surface. In a simulation, its performance is compared against that of the unscented Kalman filter (UKF), divided difference filter (DDF), iterated unscented Kalman filter (IUKF) and iterated divided difference filter (IDDF) both using a traditional iteration strategy. Simulation results demonstrate that the accumulated mean-square root error for the MLIDDF algorithm in position is reduced by 63% compared to that of UKF and DDF algorithms, and by 7% compared to that of IUKF and IDDF algorithms. The new algorithm thus has better state estimation accuracy and a fast convergence rate.

Wang, Changyuan; Zhang, Jing; Mu, Jing

2012-01-01

264

Investigation of cryogenic irradiation influence on mechanical and physical properties of ITER magnetic system insulation materials  

NASA Astrophysics Data System (ADS)

A set of methods of cryogenic irradiation influence test on mechanical and physical properties of insulation of ITER magnetic system are presented in this paper. Investigations are carried out without intermediate warming up of samples. A Russian insulating composite material was irradiated in the IVV-2M Reactor. The ratio of energy absorbed by insulation materials from neutron irradiation to that from gamma irradiation can be varied from ˜(25:75) % to ˜(50:50) % in the Reactor. The test results on the thermal expansion, thermal conductivity and gas evolution of the above material are presented. It was shown, that cryogenic irradiation up to the fluence ˜2 × 10 22 n/m 2 ( E?0.1 MeV) leads to 0.27% linear size changes along layers of fiber-glass, the thermal conductivity coefficient is decreased on 15% at 100 k in perpendicular direction to fiber-glass plane, and thermal coefficient of linear expansion (TCLE) has anomalous temperature dependence.

Kozlov, A. V.; Scherbacov, E. N.; Dudchenko, N. A.; Shihalev, V. S.; Bedin, V. V.; Paltusov, N. A.; Korsunskiy, V. E.

1998-10-01

265

Noise performance of statistical model based iterative reconstruction in clinical CT systems  

NASA Astrophysics Data System (ADS)

The statistical model based iterative reconstruction (MBIR) method has been introduced to clinical CT systems. Due to the nonlinearity of this method, the noise characteristics of MBIR are expected to differ from those of filtered backprojection (FBP). This paper reports an experimental characterization of the noise performance of MBIR equipped on several state-of-the-art clinical CT scanners at our institution. The thoracic section of an anthropomorphic phantom was scanned 50 times to generate image ensembles for noise analysis. Noise power spectra (NPS) and noise standard deviation maps were assessed locally at different anatomical locations. It was found that MBIR lead to significant reduction in noise magnitude and improvement in noise spatial uniformity when compared with FBP. Meanwhile, MBIR shifted the NPS of the reconstructed CT images towards lower frequencies along both the axial and the z frequency axes. This effect was confirmed by a relaxed slice thicknesstradeoff relationship shown in our experimental data. The unique noise characteristics of MBIR imply that extra effort must be made to optimize CT scanning parameters for MBIR to maximize its potential clinical benefits.

Li, Ke; Tang, Jie; Chen, Guang-Hong

2014-03-01

266

Critical Design Issues of Tokamak Cooling Water System of ITER's Fusion Reactor  

SciTech Connect

U.S. ITER is responsible for the design, engineering, and procurement of the Tokamak Cooling Water System (TCWS). The TCWS transfers heat generated in the Tokamak to cooling water during nominal pulsed operation 850 MW at up to 150 C and 4.2 MPa water pressure. This water contains radionuclides because impurities (e.g., tritium) diffuse from in-vessel components and the vacuum vessel by water baking at 200 240 C at up to 4.4MPa, and corrosion products become activated by neutron bombardment. The system is designated as safety important class (SIC) and will be fabricated to comply with the French Order concerning nuclear pressure equipment (December 2005) and the EU Pressure Equipment Directive using ASME Section VIII, Div 2 design codes. The complexity of the TCWS design and fabrication presents unique challenges. Conceptual design of this one-of-a-kind cooling system has been completed with several issues that need to be resolved to move to next stage of the design. Those issues include flow balancing between over hundreds of branch pipelines in parallel to supply cooling water to blankets, determination of optimum flow velocity while minimizing the potential for cavitation damage, design for freezing protection for cooling water flowing through cryostat (freezing) environment, requirements for high-energy piping design, and electromagnetic impact to piping and components. Although the TCWS consists of standard commercial components such as piping with valves and fittings, heat exchangers, and pumps, complex requirements present interesting design challenges. This paper presents a brief description of TCWS conceptual design and critical design issues that need to be resolved.

Kim, Seokho H [ORNL; Berry, Jan [ORNL

2011-01-01

267

US ITER Management Plan.  

National Technical Information Service (NTIS)

This US ITER Management Plan is the plan for conducting the Engineering Design Activities within the US. The plan applies to all design, analyses, and associated physics and technology research and development (R&D) required to support the program. The pl...

1991-01-01

268

Preliminary Master Logic Diagram for ITER operation  

SciTech Connect

This paper describes the work performed to develop a Master Logic Diagram (MLD) for the operations phase of the International Thermonuclear Experimental Reactor (ITER). The MLD is a probabilistic risk assessment tool used to identify the broad set of potential initiating events that could lead to an offsite radioactive or toxic chemical release from the facility under study. The MLD described here is complementary to the failure modes and effects analyses (FMEAs) that have been performed for ITER`s major plant systems in the engineering evaluation of the facility design. While the FMEAs are a bottom-up or component level approach, the MLD is a top-down or facility level approach to identifying the broad spectrum of potential events. Strengths of the MLD are that it analyzes the entire plant, depicts completeness in the accident initiator process, provides an independent method for identification, and can also identify potential system interactions. MLDs have been used successfully as a hazard analysis tool. This paper describes the process used for the ITER MLD to treat the variety of radiological and toxicological source terms present in the ITER design. One subtree of the nineteen page MLD is shown to illustrate the levels of the diagram.

Cadwallader, L.C. [INEEL, Idaho Falls, ID (United States); Taylor, N.P.; Poucet, A.E. [ITER San Diego Joint Work Site, La Jolla, CA (United States)

1998-04-01

269

Two Systems Safety Analyses Useful in Examining the Vulnerabilities of Security Systems  

Microsoft Academic Search

Systems safety methods can be used to better understand the threats and vulnerabilities in complex technological systems. They provide comprehensive, well-reasoned, and easily communicated analyses of the vulnerabilities of security systems. This article provides a primer on the use of the two most adaptable and useful among the many systems safety methods: Failure Modes and Effects Analysis and Fault Tree

Norman E. Groner

2008-01-01

270

Modifying the Medical Research Council grading system through Rasch analyses  

PubMed Central

The Medical Research Council grading system has served through decades for the evaluation of muscle strength and has been recognized as a cardinal feature of daily neurological, rehabilitation and general medicine examination of patients, despite being respectfully criticized due to the unequal width of its response options. No study has systematically examined, through modern psychometric approach, whether physicians are able to properly use the Medical Research Council grades. The objectives of this study were: (i) to investigate physicians’ ability to discriminate among the Medical Research Council categories in patients with different neuromuscular disorders and with various degrees of weakness through thresholds examination using Rasch analysis as a modern psychometric method; (ii) to examine possible factors influencing physicians’ ability to apply the Medical Research Council categories through differential item function analyses; and (iii) to examine whether the widely used Medical Research Council 12 muscles sum score in patients with Guillain–Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy would meet Rasch model's expectations. A total of 1065 patients were included from nine cohorts with the following diseases: Guillain–Barré syndrome (n?=?480); myotonic dystrophy type-1 (n?=?169); chronic inflammatory demyelinating polyradiculoneuropathy (n?=?139); limb-girdle muscular dystrophy (n?=?105); multifocal motor neuropathy (n?=?102); Pompe's disease (n?=?62) and monoclonal gammopathy of undetermined related polyneuropathy (n?=?8). Medical Research Council data of 72 muscles were collected. Rasch analyses were performed on Medical Research Council data for each cohort separately and after pooling data at the muscle level to increase category frequencies, and on the Medical Research Council sum score in patients with Guillain–Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy. Disordered thresholds were demonstrated in 74–79% of the muscles examined, indicating physicians’ inability to discriminate between most Medical Research Council categories. Factors such as physicians’ experience or illness type did not influence these findings. Thresholds were restored after rescoring the Medical Research Council grades from six to four options (0, paralysis; 1, severe weakness; 2, slight weakness; 3, normal strength). The Medical Research Council sum score acceptably fulfilled Rasch model expectations after rescoring the response options and creating subsets to resolve local dependency and item bias on diagnosis. In conclusion, a modified, Rasch-built four response category Medical Research Council grading system is proposed, resolving clinicians’ inability to differentiate among its original response categories and improving clinical applicability. A modified Medical Research Council sum score at the interval level is presented and is recommended for future studies in Guillain–Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy.

Vanhoutte, Els Karla; Faber, Catharina Gerritdina; van Nes, Sonja Ingrid; Jacobs, Bart Casper; van Doorn, Pieter Antoon; van Koningsveld, Rinske; Cornblath, David Reid; van der Kooi, Anneke Jelly; Cats, Elisabeth Aviva; van den Berg, Leonard Hendrik; Notermans, Nicolette Claudia; van der Pol, Willem Lodewijk; Hermans, Mieke Catharina Elisabeth; van der Beek, Nadine Anna Maria Elisabeth; Gorson, Kenneth Craig; Eurelings, Marijke; Engelsman, Jeroen; Boot, Hendrik; Meijer, Ronaldus Jacobus; Lauria, Giuseppe; Tennant, Alan

2012-01-01

271

Comparative Genomic Analyses of the Bacterial Phosphotransferase System  

PubMed Central

We report analyses of 202 fully sequenced genomes for homologues of known protein constituents of the bacterial phosphoenolpyruvate-dependent phosphotransferase system (PTS). These included 174 bacterial, 19 archaeal, and 9 eukaryotic genomes. Homologues of PTS proteins were not identified in archaea or eukaryotes, showing that the horizontal transfer of genes encoding PTS proteins has not occurred between the three domains of life. Of the 174 bacterial genomes (136 bacterial species) analyzed, 30 diverse species have no PTS homologues, and 29 species have cytoplasmic PTS phosphoryl transfer protein homologues but lack recognizable PTS permeases. These soluble homologues presumably function in regulation. The remaining 77 species possess all PTS proteins required for the transport and phosphorylation of at least one sugar via the PTS. Up to 3.2% of the genes in a bacterium encode PTS proteins. These homologues were analyzed for family association, range of protein types, domain organization, and organismal distribution. Different strains of a single bacterial species often possess strikingly different complements of PTS proteins. Types of PTS protein domain fusions were analyzed, showing that certain types of domain fusions are common, while others are rare or prohibited. Select PTS proteins were analyzed from different phylogenetic standpoints, showing that PTS protein phylogeny often differs from organismal phylogeny. The results document the frequent gain and loss of PTS protein-encoding genes and suggest that the lateral transfer of these genes within the bacterial domain has played an important role in bacterial evolution. Our studies provide insight into the development of complex multicomponent enzyme systems and lead to predictions regarding the types of protein-protein interactions that promote efficient PTS-mediated phosphoryl transfer.

Barabote, Ravi D.; Saier, Milton H.

2005-01-01

272

Improvements in Hanford TRU Program Utilizing Systems Modeling and Analyses  

SciTech Connect

Hanford's Transuranic (TRU) Program is responsible for certifying contact-handled (CH) TRU waste and shipping the certified waste to the Waste Isolation Pilot Plant (WIPP). Hanford's CH TRU waste includes material that is in retrievable storage as well as above ground storage, and newly generated waste. Certifying a typical container entails retrieving and then characterizing it (Non-Destructive Examination [NDE], Non-Destructive Assay [NDA], and Head Space Gas Sampling [HSG]), validating records (data review and reconciliation), and designating the container for a payload. The certified payload is then shipped to WIPP. Systems modeling and analysis techniques were applied to Hanford's TRU Program to help streamline the certification process and increase shipping rates. The modeling and analysis yields several benefits: - Maintains visibility on system performance and predicts downstream consequences of production issues. - Predicts future system performance with higher confidence, based on tracking past performance. - Applies speculation analyses to determine the impact of proposed changes (e.g., apparent shortage of feed should not be used as basis to reassign personnel if more feed is coming in the queue). - Positively identifies the appropriate queue for all containers (e.g., discovered several containers that were not actively being worked because they were in the wrong 'physical' location - method used previously for queuing up containers). - Identifies anomalies with the various data systems used to track inventory (e.g., dimensional differences for Standard Waste Boxes). A model of the TRU Program certification process was created using custom queries of the multiple databases for managing waste containers. The model was developed using a simplified process chart based on the expected path for a typical container. The process chart was augmented with the remediation path for containers that do not meet acceptance criteria for WIPP. Containers are sorted into queues based on their current status in the process. A container can be in only one queue at any given time. Existing data systems are queried to establish the quantity of containers in each queue on any given day. This sets the amount of feed available that is then modeled to be processed according to the daily production plans. The daily production plans were created by identifying the equipment necessary and the staff that performs each process step, and determining the expected production rate for each step. Production performance is monitored on a weekly basis with Project senior staff to establish a total operating efficiency (TOE) for each step (comparing actual performance to production capacity). The unit operations were modeled to be constrained by each day's feed queue plus the performance of the preceding step. The TOE for each unit operation was applied to an integrated model to determine bottlenecks and identify areas for improvement. All of the steps were linked to predict future system performance based on available feed and integrated system-level TOE. It has been determined that at times sub-optimization of a particular unit operation is necessary to ensure the system remains balanced (e.g., having excess capacity in assay does no good if there is no feed available because the real-time radiography [RTR] is working at half capacity). Several recommendations have been provided to the Project management team resulting in improvements in the performance of TRU certification activities by Hanford's TRU Program. (authors)

Baynes, P.A.; Bailey, K.B.; McKenney, D.E. [Fluor Hanford, Inc., Richland, WA (United States); Uytioco, E. [Fluor Government Group, Richland, WA (United States)

2008-07-01

273

Experimental and numerical analyses on LiSO 4 and Li 2TiO 3 pebble beds used in a ITER test blanket module  

NASA Astrophysics Data System (ADS)

One of the possible configurations of test blanket module (TBM) which will be tested during the ITER operation phase is made up of neutron multiplier and breeder as pebble beds. This paper describes an experimental device for the determination of the pebble bed conductivity in presence of interstitial air. The tests were performed with a simultaneous compression of the bed in order to obtain the effective bed conductivity versus the axial deformation for several values of the temperature. The effective conductivities of LiSiO 4 and Li 2TiO 3 pebble beds, both in air and in vacuum, were determined. The packing factors of the beds were measured by means an ad hoc built instrumentation, based on the gamma ray backscattering. The experimental results have been compared with those of a theoretical model developed by the authors, obtaining a good agreement in terms of bed conductivity and stiffness.

Aquaro, Donato; Zaccari, Nicola

2007-08-01

274

Nuclear systems and testing programs for ITER. Progress report for FY 1998.  

National Technical Information Service (NTIS)

The effort during this performance period focused on a number of TBWG activities (including test module design and analysis) that were identified and agreed upon (in the presence of the ITER Director and Deputy Director) at TBWG- 4. These include: (a) DEM...

1998-01-01

275

An iterative possibilistic image segmentation system: Application to breast cancer detection  

Microsoft Academic Search

A novel approach for digital mammograms segmentation is proposed. This approach aims to segment the mammograms using an iterative fusion process of information obtained from multiple sources of knowledge (contextual, image processing algorithm, a priori knowledge, etc). Initial Fuzzy Membership Maps (IFMMs) of different thematic classes are first estimated using available information. These IFMM's are then interpreted as Possibility Distribution

Waël Eziddin; J. Montagner; B. Solaiman

2010-01-01

276

Preparing ITER ICRF: Test of the Load Resilient Matching Systems on an Antenna Mock-up  

Microsoft Academic Search

The reference design for the ICRF antenna of ITER is constituted by a tight array of 24 straps grouped in 8 triplets. The matching network must be load resilient for operation in ELMy discharges and must have wave spectrum control for heating or current drive operation. The load resilience is based on the use of either hybrid couplers or Conjugate-T

P. Dumortier; D. Grine; R. Koch; P. U. Lamalle; F. Louche; A. Messiaen; M. Vervier; R. Weynants

277

RF Matching Feedback Control Systems on the JET ITER-Like Antenna  

Microsoft Academic Search

Ion Cyclotron Resonance Frequency (ICRF) antennas achieve maximum power transfer from RF generator to plasma load by establishing an impedance match. The JET ITER-Like Antenna (ILA) consists of 4 mutually coupled resonators that need to be matched simultaneously and whose resonant states need to be accurately controlled by several available actuators to couple maximum power and to achieve optimal ELM

M. Vrancken; A. Argouarch; T. Blackman; P. Dumortier; F. Durodié; R. H. Goulding; M. Graham; S. Huygen; P. Jacquet; E. Lerche; M.-L. Mayoral; A. M. Messiaen; M. P. S. Nightingale; J. Ongena; D. van Eester; M. van Schoor; M. Vervier; R. Weynants; A. Whitehurst; JET-EFDA contributors

2009-01-01

278

Progress on the ITER H&CD EC Upper Launcher Steering-Mirror Control System  

Microsoft Academic Search

The ITER Heating and Current Drive Upper Launcher (H & CD EC UL) uses a pneumomechanical steering-mirror assembly (SMA) to steer the RF beams for their deposition in the appropriate location in the plasma to control magnetohydrodynamic activity (neoclassical tearing modes (NTMs) and sawtooth oscillations). For NTM stabilization, the mirror rotation needs to be controlled to an accuracy that is

Andrés Collazos; Robert Bertizzolo; Réné Chavan; Frédéric Dolizy; Federico Felici; Timothy P. Goodman; Mark A. Henderson; Jean-Daniel Landis; Francisco Sanchez

2010-01-01

279

An iterative interacting method for dynamic analysis of the maglev train–guideway\\/foundation–soil system  

Microsoft Academic Search

This paper presents an iterative interacting method for analyzing the dynamic response of a maglev train traveling on an elevated guideway supported by piers embedded in soil. The maglev train is idealized as a row of 2D rigid beams each suspended by levitation forces and controlled by onboard PID controllers. The guideway is modeled as a series of simple beams

Y. B. Yang; J. D. Yau

2011-01-01

280

On The Problem Of In-vessel Mirrors For Diagnostic Systems Of ITER  

SciTech Connect

The present status of the investigations with ITER-candidate mirror materials and directed on solution of the in-vessel mirror problem, are presented in the paper. The current tasks in the R and D of diagnostic mirrors and outstanding questions are discussed.

Voitsenya, V. S. [IPP, NSC Kharkov Institute of Physics and Technology, Kharkov 61108 (Ukraine); Litnovsky, A. [Institut fuer Energieforschung - Plasmaphysik, Forschungszentrum Juelich, Ass. EURATOM- FZ Juelich, D-52425 Juelich (Germany)

2008-03-12

281

Air pollution control system research: An iterative approach to developing affordable systems  

NASA Technical Reports Server (NTRS)

This paper describes a Strategic Environmental Research and Development Program (SERDP) funded project led jointly by the Marine Corps Multi-Commodity Maintenance Centers, and the Air and Energy Engineering Research Laboratory (AEERL) of the USEPA. The research focuses on paint booth exhaust minimization using recirculation, and on volatile organic compound (VOC) oxidation by the modules of a hybrid air pollution control system. The research team is applying bench, pilot and full scale systems to accomplish the goals of reduced cost and improved effectiveness of air treatment systems for paint booth exhaust.

Watt, Lewis C.; Cannon, Fred S.; Heinsohn, Robert J.; Spaeder, Timothy A.

1995-01-01

282

A Comparison of Modifications to MELCOR versions 1.8.2 and 1.8.6 for ITER Safety Analysis  

Microsoft Academic Search

During the Engineering Design Activity of the International Thermonuclear Experimental Reactor (ITER), the MELCOR 1.8.2 code was selected as one of several codes to be used to perform ITER safety analyses [1]. MELCOR was chosen because it has the capability of predicting coolant pressure, temperature, mass flow rate, and radionuclide and aerosol transport in nuclear facilities and reactor cooling systems.

B. J. Merrill; P. W. Humrickhouse

2010-01-01

283

The silicon trypanosome: a test case of iterative model extension in systems biology.  

PubMed

The African trypanosome, Trypanosoma brucei, is a unicellular parasite causing African Trypanosomiasis (sleeping sickness in humans and nagana in animals). Due to some of its unique properties, it has emerged as a popular model organism in systems biology. A predictive quantitative model of glycolysis in the bloodstream form of the parasite has been constructed and updated several times. The Silicon Trypanosome is a project that brings together modellers and experimentalists to improve and extend this core model with new pathways and additional levels of regulation. These new extensions and analyses use computational methods that explicitly take different levels of uncertainty into account. During this project, numerous tools and techniques have been developed for this purpose, which can now be used for a wide range of different studies in systems biology. PMID:24797926

Achcar, Fiona; Fadda, Abeer; Haanstra, Jurgen R; Kerkhoven, Eduard J; Kim, Dong-Hyun; Leroux, Alejandro E; Papamarkou, Theodore; Rojas, Federico; Bakker, Barbara M; Barrett, Michael P; Clayton, Christine; Girolami, Mark; Krauth-Siegel, R Luise; Matthews, Keith R; Breitling, Rainer

2014-01-01

284

Improved labelling diversity for iteratively-decoded multi-antenna systems  

Microsoft Academic Search

In this work the labelling diversity scheme is deve­ loped. The Binary Switching Algorithm is employed to find an optimized 2-dimensional labelling map of 16-QAM constellation, which, applied in conjunction with the best map for iteratively­ decoded bit-interleaved space-time coded modulation (BI-STCM­ ID), enhances the advantages of multi-antenna transmission. Properties of the proposed scheme are compared with the original BI-STCM-ID

Maciej Krasicki

2011-01-01

285

Development of the JET Ion Cyclotron Resonance Frequency Heating System in Support of ITER  

Microsoft Academic Search

Three new improvements have recently been made to the JET Ion Cyclotron Resonance Frequency (ICRF) antennae to increase coupled power density and to m atch through rapid coupling variations during Edge Localised Modes (ELM's); both of which are key developments for the future design of the ITER ICRF antenna. Firstly, 3dB couplers were fitted to two antennae in 2004\\/5. Se

C. R. Frascati

286

Iterative Joint-Over-Antenna Detection and WNRA Decoding in Single-Carrier Multiuser MIMO Systems  

Microsoft Academic Search

In this paper, we propose a combined iterative detection and decoding technique that is capable of achieving the maximum diversity of order NTtimesLtimesNR over single-carrier multiple-input-multiple-output (MIMO) frequency-selective Rayleigh fading channels, where NT and NR denote the number of transmit and receive antennas, respectively, and L is the number of multipath components. The so-called space-time weighted-nonbinary-repeat-accumulate (ST-WNRA) codes are considered

Kai Yen; Nenad Veselinovic; Kimmo Kansanen; Tadashi Matsumoto

2007-01-01

287

60 Ghz Antenna System Analyses for Intersatellite Links, Phase A.  

National Technical Information Service (NTIS)

A tradeoff study for 60 GHz antenna systems applicable to an advanced Tracking and Data Acquisition System is also discussed. A conceptual design of a preferred antenna system is also discussed. The tradeoff results for four types of antenna systems are p...

1984-01-01

288

Iterative source coded modulation: turbo error concealment by iterative demodulation  

Microsoft Academic Search

In this paper we propose to combine the exploitation of residual source redundancy and iterative demodulation of multilevel modulations in a turbo-like process to improve error concealment for the source codec parameters. The developed system, denoted as iterative source coded modulation (ISCM), uses the bandwidth efficiently since no channel code increases the transmitted bit rate. Thus, ISCM is suitable for

Thorsten Clevorn; Peter Vary; Marc Adrat

2004-01-01

289

Proposal of actively heated, long stem based Cs delivery system for diagnostic neutral beam source in ITER  

NASA Astrophysics Data System (ADS)

Positioning of Cesium (Cs) oven modules in the complex interface dominated space envelope of a negative ion source such as Diagnostic Neutral Beam (DNB) source for ITER is a challenge not only for the designer of the ion source, but also that of remote handling. A more user friendly design of the Cs delivery could emerge from the consideration of a possibility of injecting the Cs from an oven located outside the vacuum envelope of the ion source, thereby ensuring an ease of Cs refilling and oven maintenance. The design of such a delivery system involves long transmission path of lengths ~4 m, from ambient to vacuum. System design involves incorporation of a low loss transmission tube enveloped by highly reflective inner surface pipe to reduce the heat losses and therefore heating of the nearby systems. A combination of all metallic valves operated at high temperatures has been incorporated in such a way that the Cs refilling or oven maintenance can be done without breaking the ion source vacuum. Removable joints in the oven heating elements are provided at specific locations to remove the Cs oven for ion source maintenance. Experimental data on Cs transmission over such a long length, required for an effective design of a co-axial transmission, is not presently available. However, an experiment has been carried out in ITER-India making measurements of Cs distribution in coaxial transmission of a length of more than 5 m. These experiments incorporate an additional feature of multiple nozzle distributor based Cs delivery into the ion source which might help in reducing the need of multiple Cs ovens in large ion sources like ITER. The Cs flux from the oven is measured by surface ionization detector (SID). The angular distribution of the Cs flux is measured by a movable SID in linear direction and has been found in good agreement with the calculations. The Cs inventory in the oven reservoir was measured by electrical resistivity measurements methods. The paper proposes to present the measurement results and also proposes a possible configuration of the Cs oven for ITER DNB ion source.

Bansal, G.; Mishra, S.; Pandya, K.; Bandyopadhyay, M.; Soni, J.; Gahlaut, A.; Parmar, K. G.; Shah, S.; Phukan, A.; Roopesh, G.; Ahmed, I.; Chakraborty, A. K.; Singh, M. J.; Schunke, B.; Hemsworth, R.; Svensson, L.; Chareyre, J.; Graceffa, J.

2013-02-01

290

Status of transmission line and matching network design and testing for the ITER ion cyclotron heating and current drive system  

NASA Astrophysics Data System (ADS)

The ITER Ion Cyclotron Heating and Current Drive System is required to deliver 20 MW of RF Power in the frequency range 40-55 MHz to ITER plasmas for pulse lengths up to 3600 s. Components used in the transmission line and matching system include 305 mm diameter, Z0 = 50 ? components with gas cooled inner conductors, and 330 mm diameter, Z0 = 20 ? components with water-cooled inner conductors. All operate at pulse lengths up to 3600 s. Components used include transmission line sections, gas barriers, hybrid power splitters, stubs, hybrid phase shifters, coaxial 4-port switches, and vacuum capacitors. The system uses pre-matching near the antenna and a matching network ˜20 m away, including decouplers that compensate for the mutual inductance between antenna array elements. Some 50 ? component test articles have been fabricated and will be shown. High power RF test fixtures have been constructed including a resonant ring that produces 6 MW of circulating power with 340 kW input power and VSWR as low as 1.15. It has been used to investigate the dependence of inner conductor temperature on gas velocity at power levels up to ˜6 MW for pulse lengths up to 1 hour.

Goulding, R. H.; McCarthy, M. P.; Rasmussen, D. A.; Swain, D. W.; Barber, G. C.; Barbier, C. N.; Campbell, I. H.; Fredd, E.; Gray, S. L.; Greenough, N.; Moon, R. L.; Pesavento, P. V.; Peters, R. B.; Sanabria, R. M.; Sparks, D. O.; Wolframe, W. J.

2014-02-01

291

Studies on the behaviour of tritium in components and structure materials of tritium confinement and detritiation systems of ITER  

Microsoft Academic Search

Confinement and the removal of tritium are key subjects for the safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell, tritium is often released as vapour and is in contact with the inner walls. The inner walls of the ITER tritium plant building will also be exposed to tritium in an accident. The tritium

K. Kobayashi; K. Isobe; Y. Iwai; T. Hayashi; W. Shu; H. Nakamura; Y. Kawamura; M. Yamada; T. Suzuki; H. Miura; M. Uzawa; M. Nishikawa; T. Yamanishi

2007-01-01

292

A General Framework for Analysing System Properties in Platform-Based Embedded System Designs  

Microsoft Academic Search

We present a framework (Real-Time Calculus) for analysing various system properties pertaining to timing analysis, loads on various components and on-chip buffer memory requirements of heterogeneous platform-based architectures, in a single coherent way. Many previous analysis techniques from the real-time systems domain, which are based on standard event models, turn out to be special cases of our framework. We illustrate

Samarjit Chakraborty; Simon Kunzli; Lothar Thiele

2003-01-01

293

Spaceborne power systems preference analyses. Volume 1: Summary  

NASA Technical Reports Server (NTRS)

Sixteen alternative spaceborne nuclear power system concepts were ranked using multiattribute decision analysis to identify promising concepts for further technology development. Four groups interviewed were: safety, systems definition and design, technology assessment, and mission analysis. The ranking results were consistent from group and for different utility function models for individuals.

Smith, J. H.; Feinberg, A.; Miles, R. F., Jr.

1985-01-01

294

Solar Electric Power System Analyses for Mars Surface Missions  

NASA Technical Reports Server (NTRS)

The electric power system is a crucial element of any architecture supporting human surface exploration of Mars. In this paper, we describe the conceptual design and detailed analysis of solar electric power system using photovoltaics and regenerative fuel cells to provide surface power on Mars. System performance, mass and deployed area predictions are discussed along with the myriad environmental factors and trade study results that helped to guide system design choices. Based on this work, we have developed a credible solar electric power option that satisfies the surface power requirements of a human Mars mission. The power system option described in this paper has a mass of approximately 10 metric tons, a approximately 5000-sq m deployable photovoltaic array using thin film solar cell technology.

Kerslake, Thomas W.; Kohout, Lisa L.

1999-01-01

295

Guide for Oxygen Hazards Analyses on Components and Systems  

NASA Technical Reports Server (NTRS)

Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite at lower temperatures in an oxygen-enriched environment than in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Many metals burn violently in an oxygen-enriched environment when ignited. Lubricants, tapes, gaskets, fuels, and solvents can increase the possibility of ignition in oxygen systems. However, these hazards do not preclude the use of oxygen. Oxygen may be safely used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. These ignition and combustion hazards necessitate a proper oxygen hazards analysis before introducing a material or component into oxygen service. The objective of this test plan is to describe the White Sands Test Facility oxygen hazards analysis to be performed on components and systems before oxygen is introduced and is recommended before implementing the oxygen component qualification procedure. The plan describes the NASA Johnson Space Center White Sands Test Facility method consistent with the ASTM documents for analyzing the hazards of components and systems exposed to an oxygen-enriched environment. The oxygen hazards analysis is a useful tool for oxygen-system designers, system engineers, and facility managers. Problem areas can be pinpointed before oxygen is introduced into the system, preventing damage to hardware and possible injury or loss of life.

Stoltzfus, Joel M.; Dees, Jesse; Poe, Robert F.

1996-01-01

296

Analyses Of Transient Events In Complex Valve and Feed Systems  

NASA Technical Reports Server (NTRS)

Valve systems in rocket propulsion systems and testing facilities are constantly subject to dynamic events resulting from the timing of valve motion leading to unsteady fluctuations in pressure and mass flow. Such events can also be accompanied by cavitation, resonance, system vibration leading to catastrophic failure. High-fidelity dynamic computational simulations of valve operation can yield important information of valve response to varying flow conditions. Prediction of transient behavior related to valve motion can serve as guidelines for valve scheduling, which is of crucial importance in engine operation and testing. In this paper, we present simulations of the diverse unsteady phenomena related to valve and feed systems that include valve stall, valve timing studies as well as cavitation instabilities in components utilized in the test loop.

Ahuja, Vineet; Hosangadi, Ashvin; Cavallo, Peter; Daines, Russell

2005-01-01

297

A Framework for Integrated Component and System Analyses of Instabilities  

NASA Technical Reports Server (NTRS)

Instabilities associated with fluid handling and operation in liquid rocket propulsion systems and test facilities usually manifest themselves as structural vibrations or some form of structural damage. While the source of the instability is directly related to the performance of a component such as a turbopump, valve or a flow control element, the associated pressure fluctuations as they propagate through the system have the potential to amplify and resonate with natural modes of the structural elements and components of the system. In this paper, the authors have developed an innovative multi-level approach that involves analysis at the component and systems level. The primary source of the unsteadiness is modeled with a high-fidelity hybrid RANS/LES based CFD methodology that has been previously used to study instabilities in feed systems. This high fidelity approach is used to quantify the instability and understand the physics associated with the instability. System response to the driving instability is determined through a transfer matrix approach wherein the incoming and outgoing pressure and velocity fluctuations are related through a transfer (or transmission) matrix. The coefficients of the transfer matrix for each component (i.e. valve, pipe, orifice etc.) are individually derived from the flow physics associated with the component. A demonstration case representing a test loop/test facility comprised of a network of elements is constructed with the transfer matrix approach and the amplification of modes analyzed as the instability propagates through the test loop.

Ahuja, Vineet; Erwin, James; Arunajatesan, Srinivasan; Cattafesta, Lou; Liu, Fei

2010-01-01

298

Various Analyses of Structures and Systems Pertaining to Optical Communications  

NASA Technical Reports Server (NTRS)

The Optical Communications Group intends to experiment with a 2 by 2 meter Fresnel lens to determine its likelihood as an alternative to focusing mirrors for optical communications. The lens was delivered in four sections. A support structure was required for the lens in order to hold the four sections in a single flat plane with an adjustable degree angle. In order to use the 200-in. Hale telescope for optical communications purposes, an optical filter membrane must used to pass the communications wavelength while blocking sunlight wavelengths. This filter must withstand wind gusts of up to 50 miles per hour. Stress analysis predicts that the membrane will survive with a safety factor greater than two. The methods used were verified by pressure testing the material. Mechanical and thermodynamic analyses were performed on a simple Golay cell in order to optimize its dimensions for best performance. Flexures are examined as an inexpensive alternative to traditional methods for kinematically constraining a 1.5-meter spherical mirror.

Petersen, Collin W.

2005-01-01

299

Vibration measurements and analyses for a magnet superconductor levitated system  

NASA Astrophysics Data System (ADS)

Magnetic levitation technology, having the characteristics of low cost and high quality, has been considered a preferable option for the next generation of launcher systems. A world-wide research design on the conceptual level has been carried out on the highly reusable space transportation systems by applying magnetic levitation to the launch assistance. Recently, a research plan has been implemented in our laboratory by constructing a scale-model suspension system with high temperature superconductor (HTS henceforth) bulks over a 7 m Nd-Fe-B permanent-magnet (PM henceforth) track for the launch assistance. An experimental platform was built to investigate the dynamic responses of the PM-HTS interaction at different field-cooled positions. The critical frequencies and amplitudes which lead to the instability of levitation drift were investigated. The stiffness and the vibration damping were also discussed at the zero-field-cooled position.

Wen, Zheng; Liu, Yu; Yang, Wenjiang; Qiu, Ming

2007-12-01

300

Learning management systems: the need for critical analyses  

Microsoft Academic Search

Learning management systems (LMSs) are receiving much attention in Nordic education. While they undoubtedly provide opportunities for educational innovations and can efficiently facilitate distance education, the enthusiasm can mask problematic consequences or preconditions which in effect sift out who may become included and who cannot. This paper points to a range of such difficulties and argues the need for voicing

Eevi E. Beck

2005-01-01

301

[Challenges to the Current Special Education System--Two Analyses.  

ERIC Educational Resources Information Center

This bulletin presents two articles which challenge the current special education system, one in terms of the conceptualization of disability and the second in terms of differential and discriminatory treatment of poor and minority youth. The first article titled "New Trends in Disability Studies: Implications for Educational Policy" (Harlan Hahn)…

NCERI Bulletin, 1995

1995-01-01

302

A System for Integrated Reliability and Safety Analyses  

NASA Technical Reports Server (NTRS)

We present an integrated reliability and aviation safety analysis tool. The reliability models for selected infrastructure components of the air traffic control system are described. The results of this model are used to evaluate the likelihood of seeing outcomes predicted by simulations with failures injected. We discuss the design of the simulation model, and the user interface to the integrated toolset.

Kostiuk, Peter; Shapiro, Gerald; Hanson, Dave; Kolitz, Stephan; Leong, Frank; Rosch, Gene; Coumeri, Marc; Scheidler, Peter, Jr.; Bonesteel, Charles

1999-01-01

303

Parallelizable restarted iterative methods for nonsymmetric linear systems. Part 1: Theory  

SciTech Connect

Large sparse nonsymmetric problems of the form Au = b are frequently solved using restarted conjugate gradient-type algorithms such as the popular GCR and GMRES algorithms. In this study the authors define a new class of algorithms which generate the same iterates as the standard GMRES algorithm but require as little as half of the computational expense. This performance improvement is obtained by using short economical three-term recurrences to replace the long recurrence used by GMRES. The new algorithms are shown to have good numerical properties in typical cases, and the new algorithms may be easily modified to be as numerically safe as standard GMRES. Numerical experiments with these algorithms are given in Part 2, in which they demonstrate the improved performance of the new schemes on different computer architectures.

Joubert, W.D.; Carey, G.F.

1991-05-01

304

Nanogold labeling of the yeast endosomal system for ultrastructural analyses.  

PubMed

Endosomes are one of the major membrane sorting checkpoints in eukaryotic cells and they regulate recycling or destruction of proteins mostly from the plasma membrane and the Golgi. As a result the endosomal system plays a central role in maintaining cell homeostasis, and mutations in genes belonging to this network of organelles interconnected by vesicular transport, cause severe pathologies including cancer and neurobiological disorders. It is therefore of prime relevance to understand the mechanisms underlying the biogenesis and organization of the endosomal system. The yeast Saccharomyces cerevisiae has been pivotal in this task. To specifically label and analyze at the ultrastructural level the endosomal system of this model organism, we present here a detailed protocol for the positively charged nanogold uptake by spheroplasts followed by the visualization of these particles through a silver enhancement reaction. This method is also a valuable tool for the morphological examination of mutants with defects in endosomal trafficking. Moreover, it is not only applicable for ultrastructural examinations but it can also be combined with immunogold labelings for protein localization investigations. PMID:25046212

Mari, Muriel; Griffith, Janice; Reggiori, Fulvio

2014-01-01

305

Numerical and experimental analyses of large composite skeletal satellite systems  

NASA Astrophysics Data System (ADS)

The world's ever increasing demand for communication capacity has been the catalyst for the development of a range of next generation satellite reflectors. This new generation of satellites is significantly larger than those currently in orbit. Their dimensions prohibit transportation into space in their operational configuration. The use of deployable tetrahedral trusses for the reflecting surface support structures of a 50 m diameter Land Mobile Communication System is investigated. A deployable structural system was selected ahead of other possible forms, as it satisfied the majority of the criteria of low part count, quick assembly times, and an economical packaging volume thereby minimizing transportation and on-orbit fabrication costs. The composite material examined is formed from a polyethersulphone thermoplastic matrix reinforced with high strength, low modulus carbon fibers, C-PES. The modal characteristics of a series of scaled sub-units of the proposed structure were examined. These units, manufactured from the two types of material considered, C-PES and Perspex, were subjected to a range of excitation functions. The C-PES units were thermally cycled under high vacuum to simulate the space environment. The accelerated thermal cycling of the composite structural units revealed that a shift in resonant frequency occurred, together with some surface cracking which could affect the long term stability of the material. The effects of surface pigmentation on the thermal response were also considered. An algorithm was developed which allows low cost materials to be used to predict the behavior of geometrically similar units manufactured from the composite material. The interaction between the predicted dynamic structural behavior and the electrical performance of the satellite is also addressed and suggests that some form of active control system will be required if the maximum defocus parameter is not to be violated.

Sparry, D. A. C.

1992-01-01

306

New progress of ITER-PF strand production in WST  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

307

System analyses on advanced nuclear fuel cycle and waste management  

NASA Astrophysics Data System (ADS)

To evaluate the impacts of accelerator-driven transmutation of waste (ATW) fuel cycle on a geological repository, two mathematical models are developed: a reactor system analysis model and a high-level waste (HLW) conditioning model. With the former, fission products and residual trans-uranium (TRU) contained in HLW generated from a reference ATW plant operations are quantified and the reduction of TRU inventory included in commercial spent-nuclear fuel (CSNF) is evaluated. With the latter, an optimized waste loading and composition in solidification of HLW are determined and the volume reduction of waste packages associated with CSNF is evaluated. WACOM, a reactor system analysis code developed in this study for burnup calculation, is validated by ORIGEN2.1 and MCNP. WACOM is used to perform multicycle analysis for the reference lead-bismuth eutectic (LBE) cooled transmuter. By applying the results of this analysis to the reference ATW deployment scenario considered in the ATW roadmap, the HLW generated from the ATW fuel cycle is quantified and the reduction of TRU inventory contained in CSNF is evaluated. A linear programming (LP) model has been developed for determination of an optimized waste loading and composition in solidification of HLW. The model has been applied to a US-defense HLW. The optimum waste loading evaluated by the LP model was compared with that estimated by the Defense Waste Processing Facility (DWPF) in the US and a good agreement was observed. The LP model was then applied to the volume reduction of waste packages associated with CSNF. Based on the obtained reduction factors, the expansion of Yucca Mountain Repository (YMR) capacity is evaluated. It is found that with the reference ATW system, the TRU contained in CSNF could be reduced by a factor of ˜170 in terms of inventory and by a factor of ˜40 in terms of toxicity under the assumed scenario. The number of waste packages related to CSNF could be reduced by a factor of ˜8 in terms of volume and by factor of ˜10 on the basis of electricity generation when a sufficient cooling time for discharged spent fuel and zero process chemicals in HLW are assumed. The expansion factor of Yucca Mountain Repository capacity is estimated to be a factor of 2.4, much smaller than the reduction factor of CSNF waste packages, due to the existence of DOE-owned spent fuel and HLW. The YMR, however, could support 10 times greater electricity generation as long as the statutory capacity of DOE-owned SNF and HLW remains unchanged. This study also showed that the reduction of the number of waste packages could strongly be subject to the heat generation rate of HLW and the amount of process chemicals contained in HLW. For a greater reduction of the number of waste packages, a sufficient cooling time for discharged fuel and efforts to minimize the amount of process chemicals contained in HLW are crucial.

Cheon, Myeongguk

308

Neutron diagnostics for ITER  

SciTech Connect

Neutron diagnostics will play a prominent role in the control and evaluation of thermonuclear plasmas in ignition device to test engineering concepts (ITER). As in present D-T experiments, measurements of neutron yield and of fusion power and power density are essential. In addition, the spectral width of the 14.1-MeV t(d,n){alpha} neutron emission should be a reliable indicator of ion temperature in an ignited plasma. More detailed measurements of the neutron spectrum may allow determination of the densities of tritium, deuterium, and confined alpha particles. Although the central fusion power density in ITER will be comparable to the maximum values obtainable in TFTR and JET, neutron flux on the first wall will be ten times higher, and the neutron yield per discharge will be about five orders of magnitude greater than previously experienced. The thermal and radiation shielding necessary to protect the ITER superconducting coils from the intense flux at the first wall will restrict diagnostic access for neutron cameras and spectrometers, complicate the design of material activation systems, and limit the applicability of conventional calibration techniques for neutron source strength monitors. These considerations, together with unprecedented reliability requirements and the need for full remote handling of many components, pose demanding challenges for the design of the ITER neutron diagnostic systems. {copyright} {ital 1997 American Institute of Physics.}

Johnson, L.C.; Barnes, C.W.; Krasilnikov, A.; Marcus, F.B.; Nishitani, T. [ITER San Diego Joint Work Site, La Jolla, California 92037 (United States)] [ITER San Diego Joint Work Site, La Jolla, California 92037 (United States)

1997-01-01

309

Natural history of alkaptonuria revisited: analyses based on scoring systems.  

PubMed

Increased circulating homogentisic acid in body fluids occurs in alkaptonuria (AKU) due to lack of enzyme homogentisate dioxygenase leading in turn to conversion of HGA to a pigmented melanin-like polymer, known as ochronosis. The tissue damage in AKU is due to ochronosis. A potential treatment, a drug called nitisinone, to decrease formation of HGA is available. However, deploying nitisinone effectively requires its administration at the most optimal time in the natural history. AKU has a long apparent latent period before overt ochronosis develops. The rate of change of ochronosis and its consequences over time following its recognition has not been fully described in any quantitative manner. Two potential tools are described that were used to quantitate disease burden in AKU. One tool describes scoring the clinical features that includes clinical assessments, investigations and questionnaires in 15 patients with AKU. The second tool describes a scoring system that only includes items obtained from questionnaires in 44 people with AKU. Analysis of the data reveals distinct phases of the disease, a pre-ochronotic phase and an ochronotic phase. The ochronotic phase appears to demonstrate an earlier slower progression followed by a rapidly progressive phase. The rate of change of the disease will have implications for monitoring the course of the disease as well as decide on the most appropriate time that treatment should be started for it to be effective either in prevention or arrest of the disease. PMID:21748407

Ranganath, Lakshminarayan R; Cox, Trevor F

2011-12-01

310

Design and RF measurements of a 5 GHz 500 kW window for the ITER LHCD system  

NASA Astrophysics Data System (ADS)

CEA/IRFM is conducting R&D efforts in order to validate the critical RF components of the 5 GHz ITER LHCD system, which is expected to transmit 20 MW of RF power to the plasma. Two 5 GHz 500 kW BeO pill-box type window prototypes have been manufactured in 2012 by the PMB Company, in close collaboration with CEA/IRFM. Both windows have been validated at low power, showing good agreement between measured and modeling, with a return loss better than 32 dB and an insertion loss below 0.05 dB. This paper reports on the window RF design and the low power measurements. The high power tests up to 500kW have been carried out in March 2013 in collaboration with NFRI. Results of these tests are also reported.

Hillairet, J.; Achard, J.; Bae, Y. S.; Bernard, J. M.; Dechambre, N.; Delpech, L.; Ekedahl, A.; Faure, N.; Goniche, M.; Kim, J.; Larroque, S.; Magne, R.; Marfisi, L.; Namkung, W.; Park, H.; Park, S.; Poli, S.; Vulliez, K.

2014-02-01

311

Tests on a mock-up of the feedback controlled matching options of the ITER ICRH system  

SciTech Connect

Automatic control of the matching of the ITER ICRH antenna array on a reference load is presently developed and tested for optimization on a low-powered scaled (1:5) mock-up. Resilience to fast load variations is obtained either by 4 Conjugate-T (CT) or 4 quadrature hybrid circuits, the latter being the reference option. The main results are (i) for the CT option: successful implementation of the simultaneous feedback control of 11 actuators for the matching of the 4 CT and for the control of the array toroidal phasing; (ii) for the hybrid option: the matching and the array current control via feedback control of the decouplers and double stub tuners. This system is being progressively implemented and the simultaneous control of matching and antenna current has already been successfully tested on half of the array for heating and current drive phasings.

Grine, D.; Vervier, M.; Messiaen, A.; Dumortier, P. [Lab. for Plasma Physics-Royal Military Academy, 30 avn. de la Rermaissance, Brussels (Belgium)

2009-11-26

312

An iterative Riemann solver for systems of hyperbolic conservation law s, with application to hyperelastic solid mechanics  

SciTech Connect

In this paper we present a general iterative method for the solution of the Riemann problem for hyperbolic systems of PDEs. The method is based on the multiple shooting method for free boundary value problems. We demonstrate the method by solving one-dimensional Riemann problems for hyperelastic solid mechanics. Even for conditions representative of routine laboratory conditions and military ballistics, dramatic differences are seen between the exact and approximate Riemann solution. The greatest discrepancy arises from misallocation of energy between compressional and thermal modes by the approximate solver, resulting in nonphysical entropy and temperature estimates. Several pathological conditions arise in common practice, and modifications to the method to handle these are discussed. These include points where genuine nonlinearity is lost, degeneracies, and eigenvector deficiencies that occur upon melting.

Miller, Gregory H.

2003-08-06

313

Intelligent Control of a Sensor-Actuator System via Kernelized Least-Squares Policy Iteration  

PubMed Central

In this paper a new framework, called Compressive Kernelized Reinforcement Learning (CKRL), for computing near-optimal policies in sequential decision making with uncertainty is proposed via incorporating the non-adaptive data-independent Random Projections and nonparametric Kernelized Least-squares Policy Iteration (KLSPI). Random Projections are a fast, non-adaptive dimensionality reduction framework in which high-dimensionality data is projected onto a random lower-dimension subspace via spherically random rotation and coordination sampling. KLSPI introduce kernel trick into the LSPI framework for Reinforcement Learning, often achieving faster convergence and providing automatic feature selection via various kernel sparsification approaches. In this approach, policies are computed in a low-dimensional subspace generated by projecting the high-dimensional features onto a set of random basis. We first show how Random Projections constitute an efficient sparsification technique and how our method often converges faster than regular LSPI, while at lower computational costs. Theoretical foundation underlying this approach is a fast approximation of Singular Value Decomposition (SVD). Finally, simulation results are exhibited on benchmark MDP domains, which confirm gains both in computation time and in performance in large feature spaces.

Liu, Bo; Chen, Sanfeng; Li, Shuai; Liang, Yongsheng

2012-01-01

314

Intelligent control of a sensor-actuator system via kernelized least-squares policy iteration.  

PubMed

In this paper a new framework, called Compressive Kernelized Reinforcement Learning (CKRL), for computing near-optimal policies in sequential decision making with uncertainty is proposed via incorporating the non-adaptive data-independent Random Projections and nonparametric Kernelized Least-squares Policy Iteration (KLSPI). Random Projections are a fast, non-adaptive dimensionality reduction framework in which high-dimensionality data is projected onto a random lower-dimension subspace via spherically random rotation and coordination sampling. KLSPI introduce kernel trick into the LSPI framework for Reinforcement Learning, often achieving faster convergence and providing automatic feature selection via various kernel sparsification approaches. In this approach, policies are computed in a low-dimensional subspace generated by projecting the high-dimensional features onto a set of random basis. We first show how Random Projections constitute an efficient sparsification technique and how our method often converges faster than regular LSPI, while at lower computational costs. Theoretical foundation underlying this approach is a fast approximation of Singular Value Decomposition (SVD). Finally, simulation results are exhibited on benchmark MDP domains, which confirm gains both in computation time and in performance in large feature spaces. PMID:22736969

Liu, Bo; Chen, Sanfeng; Li, Shuai; Liang, Yongsheng

2012-01-01

315

Web-Based Assessment and Test Analyses (WATA) System: Development and Evaluation  

ERIC Educational Resources Information Center

This study introduces the development of a Web-based assessment system, the Web-based Assessment and Test Analyses (WATA) system, and examines its impacts on teacher education. The WATA system is a follow-on system, which applies the Triple-A Model (assembling, administering, and appraising). Its functions include (1) an engine for teachers to…

Wang, T. H.; Wang, K. H.; Wang, W. L.; Huang, S. C.; Chen, S. Y.

2004-01-01

316

On the electron extraction in a large RF-driven negative hydrogen ion source for the ITER NBI system  

NASA Astrophysics Data System (ADS)

The test facility ELISE, equipped with a large RF-driven ion source (1 × 0.9 m2) of half the size of the ion source for the ITER neutral beam injection (NBI) system, has been constructed over the last three years at the Max-Planck-Institut für Plasmaphysik (IPP), Garching, and is now operational. The first measurements of the dependence of the co-extracted electron currents on various operational parameters have been performed. ELISE has the unique feature that the electron currents can be measured individually on both extraction grid segments, leading to vertical spatial resolution. Although performed in volume operation, where the negative hydrogen ions are created in the plasma volume solely, the results are very encouraging for operation with caesium, this being necessary in order to achieve the relevant negative ion currents for the ITER NBI injectors. The amount of co-extracted electrons could be suppressed sufficiently with moderate magnetic filter fields and by plasma grid bias. Furthermore, the electron extraction is more or less decoupled from the main plasma, as the observed vertical asymmetry of electron extraction is not correlated at all with the plasma asymmetry, which is anyway rather small. Both effects are superior to the experience from the small IPP prototype source; the reason for these encouraging results is most probably the larger size of the source as well as the new geometry of the source having unbiased areas in its centre. The reasons, however, for the observed asymmetry of the extracted electron currents and their dependencies on various operational parameters are not well understood.

Franzen, P.; Wünderlich, D.; Fantz, U.; the NNBI Team

2014-02-01

317

Safety-factor profile tailoring by improved electron cyclotron system for sawtooth control and reverse shear scenarios in ITER  

SciTech Connect

The effect of the predicted local electron cyclotron current driven by the optimized electron cyclotron system on ITER is discussed. A design variant was recently proposed to enlarge the physics program covered by the upper and equatorial launchers. By extending the functionality range of the upper launcher, significant control capabilities of the sawtooth period can be obtained. The upper launcher improvement still allows enough margin to exceed the requirements for neoclassical tearing mode stabilization, for which it was originally designed. The analysis of the sawtooth control is carried on with the ASTRA transport code, coupled with the threshold model by Por-celli, to study the control capabilities of the improved upper launcher on the sawtooth instability. The simulations take into account the significant stabilizing effect of the fusion alpha particles. The sawtooth period can be increased by a factor of 1.5 with co-ECCD outside the q = 1 surface, and decreased by at least 30% with co-ECCD inside q = 1. The present ITER base-line design has the electron cyclotron launchers providing only co-ECCD. The variant for the equatorial launcher proposes the possibility to drive counter-ECCD with 1 of the 3 rows of mirrors: the counter-ECCD can then be balanced with co-ECCD and provide pure ECH with no net driven current. The difference between full co-ECCD off-axis using all 20MW from the equatorial launcher and 20MW co-ECCD driven by 2/3 from the equatorial launcher and 1/3 from the upper launcher is shown to be negligible. Cnt-ECCD also offers greater control of the plasma current density, therefore this analysis addresses the performance of the equatorial launcher to control the central q profile. The equatorial launcher is shown to control very efficiently the value of q{sub 0.2}-q{sub min} in advanced scenarios, if one row provides counter-ECCD.

Zucca, C.; Sauter, O.; Fable, E. [Ecole Polytechnique Federate de Lausanne, Centre de Recherches en Physique des Plasmas, Association EURATOM-Confederation Suisse, CH-1015 Lausanne (Switzerland); Henderson, M. A.; Polevoi, A. [ITER Organization, CHD Dpt, CEN Cadarache 519/007, 13108 Saint-Paul-les-Durance (France); Farina, D.; Ramponi, G. [Istituto di Fisica del Plasma, EURATOM-Enea-CNR Association, Milano (Italy); Saibene, G. [Fusion for Energy, c/Josep Pla, 08019 Barcelona (Spain); Zohm, H. [Max Planck Institut fuer Plasmaphysik IPP-EURATOM Association, Garching (Germany)

2008-11-01

318

Neutron activation for ITER  

SciTech Connect

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

Barnes, C.W. [Los Alamos National Lab., NM (United States); Loughlin, M.J. [JET Joint Undertaking, Abingdon (United Kingdom); Nishitani, Takeo [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

1996-04-29

319

Iterative methods for mixed finite element equations  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

320

An impedance-analyser-based multi-channel imaging system and its applications  

Microsoft Academic Search

Imaging systems based on impedance measurement are widely used in medical, process monitoring and non-destructive testing, where their hardware designs, measurement range and accuracy are often application-specific. Impedance analysers can deliver excellent performance in terms of reliability, resolution and accuracy. A multi-channel imaging system has been developed using an impedance analyser with a specifically designed multiplexer box, hardware interface and

Xiaohui Hu; Min Yang; Yi Li; Wuqiang Yang; Maria Manrique de Lara

2008-01-01

321

Development of active control systems on ASDEX upgrade in view of ITER discharge scenarios  

Microsoft Academic Search

ASDEX Upgrade has a large variety of technical systems, heating and fuelling as well as digital control systems needed for control and optimisation of high performance plasmas. The neutral beam injection (NBI), electron cyclotron RF (ECRF) and ion cyclotron resonance frequency (ICRF) heating systems are able to operate in heating as well as in current drive (CD) mode. One of

V. Mertens; J. Hobirk; A. Kallenbach; P. Lang; A. Mück; G. Pautasso; G. Raupp; A. Sips; J. Stober; H. Zohm

2003-01-01

322

Yucca Mountain Project total-system performance assessment preliminary analyses: Overview; Draft  

SciTech Connect

Sandia National Laboratories and Pacific Northwest Laboratory have produced a coordinated initial total-system performance assessment analysis for the potential repository at Yucca Mountain. Analyses included radionuclide transport via groundwater and gas flow, human intrusion, tectonism, and basaltic igneous intrusion. Both abstracted and detailed calculations were used for the analyses. Probabilistic release distributions were calculated for the individual components, and a combined distribution for the overall behavior of the system was constructed. Results from the analyses using abstracted models indicate that this method produces reasonable outcomes based on our current understanding of the site.

Barnard, R.W.; Dockery, H.A.

1991-12-19

323

Thermal-Hydraulic System Study of the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM) for ITER Using System Code RELAP5  

NASA Astrophysics Data System (ADS)

The HCPB concept has been a European DEMO reference concept for nearly one decade. Detailed thermal-hydraulic study on the control behavior of the whole system is one of the important parts of this development. The thermal-hydraulic effect of the TBM-combined cooling circuit during a cyclic operation in ITER has been studied using the system code RELAP5. The RELAP5 is based on an one-dimensional, transient two-fluid model for the flow of a two-phase steam-water mixture that can contain noncondensable components like Helium. The RELAP5-models are modified to take the cyclic operation of the circulator, heat exchanger, bypass, valves etc in to account. A sequence of operational phases is investigated, starting from the cold state through the heating phase that brings the system to a stand-by condition, followed by typical power cycles applied in ITER. The results show that the implemented control mechanisms keep the inlet temperature to the TBM and the total mass flow rate at the required values through all phases.

Jin, Xuezhou; R, Meyder

2005-04-01

324

Probability Propagation and Iterative Decoding  

Microsoft Academic Search

In this paper, we present a unified graphical model framework for describing codes and deriving iterative decoding algorithms. We illustrate how the following systems can be described using graphical models: turbo-codes, serially-concatenated convolutional codes, frame-oriented turbo-codes, low-density parity-check codes, product codes, and convolutional codes on channels with memory. Recently proposed iterative decoding algorithms (e.g., turbo-decoding) can be viewed as a

Brendan J. Frey; Frank R. Kschischang

1996-01-01

325

An ITER-relevant evacuated waveguide transmission system for the JET-EP ECRH project  

Microsoft Academic Search

An over-moded evacuated waveguide line was chosen for use in the transmission system for the proposed JET-enhanced performance project (JET-EP) electron cyclotron resonance heating (ECRH) system. A comparison between the quasi-optical, atmospheric waveguide and evacuated waveguide systems was performed for the project with a strong emphasis placed on the technical and financial aspects. The evacuated waveguide line was chosen as

M. A. Henderson; S. Alberti; J. Bird; J. Doane; B. Elzendoorn; C. Flemming; T. P. Goodman; F. Hoekzema; J. P. Hogge; G. MacMillan; J. C. Magnin; B. Pioscyk; L. Porte; M. Q. Tran; A. G. A. Verhoeven

2003-01-01

326

Final design of a cryogenic system for the ITER CS model coil  

NASA Astrophysics Data System (ADS)

The final design of a 5-kW / 800-L/h cryogenic system was completed and the construction has been started. Cloude cycle with double JT valve system is adopted. The system will be available for 8-kW refrigeration in addition of a cryogenic turbine. High energy efficiency is expected, where 1/346 (Watt 4.5K/Watt 300K) and 1/248 at 5kW and 8kW, respectively. Re-installation of the existing cryogenic components has achieved the cost reduction of the system by more than 30%.

Hamada, K.; Nishida, K.; Kato, T.; Kawano, K.; Hiyama, T.; Miyake, A.; Sekiguchi, S.; Otsu, K.; Ebisu, H.; Tsuji, H.

327

Iterative-type evaluation of PSGS fuzzy systems for anytime use  

Microsoft Academic Search

While fuzzy systems can advantageously be used in system modeling and control, their use in time-critical applications is limited because of complexity problems, especially in cases when not only low, but also flexibly changeable complexity is needed. Previously, a method has been proposed to use fuzzy and other soft-computational tools in the frame of modular anytime architectures; however, the applicability

Orsolya Takács; Annamária R. Várkonyi-Kóczy

2005-01-01

328

Iterative-type evaluation of PSGS fuzzy systems for anytime use  

Microsoft Academic Search

While fuzzy systems can advantageously be used in system modeling and control, their use in time-critical applications is limited because of complexity problems, especially in cases, when not only low, but also flexibly changeable complexity is needed. Previously a method has been proposed to use fuzzy and other soft-computational tools in the frame of modular anytime architectures; however, the applicability

O. Takacs; A. R. Varkonyi-Kozy

2002-01-01

329

Simulations of ITER scenarios  

Microsoft Academic Search

To improve the efficiency of operation of the tokamak reactor (International Thermonuclear Experi-mental Reactor, ITER) in future, it is highly desirable to perform a comprehensive validation by numerical simulation of newly-proposed scenarios or controllers before operation. This paper describes the results of the first stage in these simulations, performed for ITER [ITER Technical Basis. ITER EDA Documentation Series No. 24

V. Lukash; Y. Gribov; A. Kavin; R. Khayrutdinov; M. Cavinato

2005-01-01

330

Final design of a cryogenic system for the ITER CS model coil  

Microsoft Academic Search

The final design of a 5-kW \\/ 800-L\\/h cryogenic system was completed and the construction has been started. Cloude cycle with double JT valve system is adopted. The system will be available for 8-kW refrigeration in addition of a cryogenic turbine. High energy efficiency is expected, where 1\\/346 (Watt 4.5K\\/Watt 300K) and 1\\/248 at 5kW and 8kW, respectively. Re-installation of

K. Hamada; K. Nishida; T. Kato; K. Kawano; T. Hiyama; A. Miyake; S. Sekiguchi; K. Otsu; H. Ebisu; H. Tsuji

1994-01-01

331

Block-iterative generalized decision feedback equalizers for large MIMO systems: algorithm design and asymptotic performance analysis  

Microsoft Academic Search

This paper studies the problem of signal detection for multiple-input multiple-output (MIMO) channels with large signal dimensions. We propose a block-iterative generalized de- cision feedback equalization (BI-GDFE) receiver to recover the transmitted symbols in a block-iterative manner. By exploiting the input-decision correlation, a measure for the reliability of the ear- lier-made decisions, we design the feed-forward equalizers (FFEs) and feedback

Ying-Chang Liang; Sumei Sun; Chin Keong Ho

2006-01-01

332

Signal detection for large MIMO systems using block-iterative generalized decision feedback equalizers (BI-GDFE)  

Microsoft Academic Search

This paper studies the problem of signal detection for generic MIMO channels with large signal dimensions. We propose a block-iterative generalized decision feedback equalization (BI-GDFE) receiver to recover the transmitted symbols in a block-iterative manner. By exploiting the input-decision correlation (IDC), a measure for the reliability of the earlier-made decisions, we design the feed-forward equalizers (FFEs) and feedback equalizers (FBEs)

Ying-Chang Liang; Sumei Sun; Chin Keong Ho

2005-01-01

333

Iterative Channel Estimation based on Linear Regression for a MIMO MC-CDMA system  

Microsoft Academic Search

Multiple-input multiple-output MC-CDMA systems receive a great deal of attention due to their great potential in achieving high data rates in wireless communications. Nevertheless, performance of MIMO MC-CDMA systems can severely degrade due to inaccurate channel estimation especially over frequency-selective fast-varying channels. In this paper, we address a MIMO MC-CDMA coherent transmission with a pilot aided turbo channel estimation improved

B. L. Saux; M. Helard; L. Boher

2006-01-01

334

Acceleration of MeV-class energy, high-current-density H{sup -}-ion beams for ITER neutral beam system  

SciTech Connect

For the ITER neutral beam system, research and development of a vacuum-insulated MeV accelerator has been carried out at Japan Atomic Energy Research Institute. After a successful 1 MV insulation in vacuum for more than 2 h, H{sup -}-ion-beam acceleration test is in progress to fulfill the ITER requirement of the current density of 200 A/m{sup 2} at 1 MeV, with good beam optics quality of <7 mrad divergence. For such a high-current-density H{sup -}-ion-beam acceleration, the Kamaboko negative-ion source was operated at high input power, with increased filament number and magnetic filter strength. The optimum perveance was investigated by scanning the extraction and acceleration voltages, together with the beam divergence measurement. As a consequence, H{sup -}-ion beams of 146 A/m{sup 2} (total ion-beam current: 206 mA) were obtained at 836 keV, of which power density is in the 'ITER relevant' level. Such high-power-density beams with a divergence as low as 5 mrad were obtained at the optimum perveance corresponding to that of the ITER (200 A/m{sup 2} at 1 MeV)

Taniguchi, M.; Inoue, T.; Kashiwagi, M.; Watanabe, K.; Hanada, M.; Seki, T.; Dairaku, M.; Sakamoto, K. [Japan Atomic Energy Agency, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka 311-0193 (Japan)

2006-03-15

335

Performance Metrics for Liquid Chromatography-Tandem Mass Spectrometry Systems in Proteomics Analyses*  

PubMed Central

A major unmet need in LC-MS/MS-based proteomics analyses is a set of tools for quantitative assessment of system performance and evaluation of technical variability. Here we describe 46 system performance metrics for monitoring chromatographic performance, electrospray source stability, MS1 and MS2 signals, dynamic sampling of ions for MS/MS, and peptide identification. Applied to data sets from replicate LC-MS/MS analyses, these metrics displayed consistent, reasonable responses to controlled perturbations. The metrics typically displayed variations less than 10% and thus can reveal even subtle differences in performance of system components. Analyses of data from interlaboratory studies conducted under a common standard operating procedure identified outlier data and provided clues to specific causes. Moreover, interlaboratory variation reflected by the metrics indicates which system components vary the most between laboratories. Application of these metrics enables rational, quantitative quality assessment for proteomics and other LC-MS/MS analytical applications.

Rudnick, Paul A.; Clauser, Karl R.; Kilpatrick, Lisa E.; Tchekhovskoi, Dmitrii V.; Neta, Pedatsur; Blonder, Niksa; Billheimer, Dean D.; Blackman, Ronald K.; Bunk, David M.; Cardasis, Helene L.; Ham, Amy-Joan L.; Jaffe, Jacob D.; Kinsinger, Christopher R.; Mesri, Mehdi; Neubert, Thomas A.; Schilling, Birgit; Tabb, David L.; Tegeler, Tony J.; Vega-Montoto, Lorenzo; Variyath, Asokan Mulayath; Wang, Mu; Wang, Pei; Whiteaker, Jeffrey R.; Zimmerman, Lisa J.; Carr, Steven A.; Fisher, Susan J.; Gibson, Bradford W.; Paulovich, Amanda G.; Regnier, Fred E.; Rodriguez, Henry; Spiegelman, Cliff; Tempst, Paul; Liebler, Daniel C.; Stein, Stephen E.

2010-01-01

336

A Laser Metrology/Viewing System for ITER In-Vessel Inspection  

SciTech Connect

This paper identifies the requirements for a remotely operated precision laser ranging system for the International Thermonuclear Experimental Reactor. The inspection system is used for metrology and viewing, and must be capable of achieving submillimeter accuracy and operation in a reactor vessel that has high gamma radiation, high vacuum, elevated temperature, and magnetic field levels. A coherent, frequency modulated laser radar system is under development to meet these requirements. The metrology/viewing sensor consists of a compact laser-optic module linked through fiberoptics to the laser source and imaging units, located outside the harsh environment. The deployment mechanism is a remotely operated telescopic mast. Gamma irradiation up to 10{sup 7} Gy was conducted on critical sensor components with no significant impact to data transmission, and analysis indicates that critical sensor components can operate in a magnetic field with certain design modifications. Plans for testing key components in a magnetic field are underway.

Spampinato, P.T.; Barry, R.E.; Chesser, J.B.; Menon, M.M. [Oak Ridge National Lab., TN (United States); Dagher, M.A. [Boeing Rocketdyne Div., Canoga Park, CA (United States); Slotwinski, A. [Coleman Research Corp., Springfield, VA (United States)

1997-12-31

337

An approximation method to analyse polling models of pull-type production systems  

Microsoft Academic Search

In this paper, a polling model with finite queues to analyse a production system that is operating under a pull-type control mechanism is studied. The polling model is analysed under three well-known service policies namely, exhaustive, gated and g-limited. These policies determine when and how machines switch from one part to another. These polling models can be solved by an

Mustafa Karakul; Abdullah Dasci

2007-01-01

338

Development and demonstration of a supercritical helium-cooled cryogenic viscous compressor prototype for the iter vacuum system  

NASA Astrophysics Data System (ADS)

As part of the vacuum system for the ITER fusion project, a cryogenic viscouscompressor (CVC) is being developed to collect hydrogenic exhaust gases from the toruscryopumps and compress them to a high enough pressure by regeneration for pumping tothe tritium reprocessing facility. Helium impurities that are a byproduct of the fusionreactions pass through the CVC and are pumped by conventional vacuum pumps andexhausted to the atmosphere. Before the development of a full-scale CVC, a representative,small-scale test prototype was designed, fabricated, and tested. With cooling provided bycold helium gas, hydrogen gas was introduced into the central column of the test prototypepump at flow rates between 0.001 g/s and 0.008 g/s. Based on the temperatures and flowrates of the cold helium gas, different percentages of hydrogen gas were frozen to the column surface wall as the hydrogen gas flow rate increased. Results from the measured temperatures and pressures will form a benchmark that will be used to judge future heattransfer enhancements to the prototype CVC and to develop a computational fluid dynamicmodel that will help develop design parameters for the full-scale CVC.

Duckworth, Robert C.; Baylor, Larry R.; Meitner, Steven J.; Combs, Stephen K.; Rasmussen, David A.; Hechler, Michael; Edgemon, Timothy; Barbier, Charlotte; Pearce, Robert; Kersevan, Roberto; Dremel, Matthias; Boissin, Jean-Claude

2012-06-01

339

Assessment of Collateral Effects to Tokamak Systems During Planned Air Baking of DIII-D to Simulate ITER Tritium Removal  

NASA Astrophysics Data System (ADS)

Thermo-oxidation is a method for removing carbon-based co-deposits and is unique in its ability to remove deuterium from tokamak co-deposits, including tile gaps and shaded areas. This is a possible technique for tritium removal on ITER. In these experiments, we examine the potential collateral (deleterious) effects of a thermo-oxidation experiment planned for DIII-D. Experiments at Toronto have set the process parameters to be 10 Torr air exposure at 250^o -350^oC for two hours. Components of interest were placed in a vacuum chamber filled with O2 or air and baked at 250^o and 350^oC. Components were examined for visual or mechanical changes, and when appropriate, mass change. In special cases, optical or electromagnetic diagnostics were performed. Components tested spanned a wide variety of materials and functions, e.g., cryopump components, structural, mechanical and diagnostic components, and fast wave antennae. To date, nearly all DIII-D systems have passed these tests. Detailed results will be presented.

Fitzpatrick, B. W. N.; Davis, J. W.; Haasz, A. A.; Stangeby, P. C.; Allen, S. L.; Ellis, R.; West, W. P.

2008-11-01

340

DEVELOPMENT AND DEMONSTRATION OF A SUPERCRITICAL HELIUM-COOLED CRYOGENIC VISCOUS COMPRESSOR PROTOTYPE FOR THE ITER VACUUM SYSTEM  

SciTech Connect

As part of the vacuum system for the ITER fusion project, a cryogenic viscouscompressor (CVC) is being developed to collect hydrogenic exhaust gases from the toruscryopumps and compress them to a high enough pressure by regeneration for pumping tothe tritium reprocessing facility. Helium impurities that are a byproduct of the fusionreactions pass through the CVC and are pumped by conventional vacuum pumps andexhausted to the atmosphere. Before the development of a full-scale CVC, a representative,small-scale test prototype was designed, fabricated, and tested. With cooling provided bycold helium gas, hydrogen gas was introduced into the central column of the test prototypepump at flow rates between 0.001 g/s and 0.008 g/s. Based on the temperatures and flowrates of the cold helium gas, different percentages of hydrogen gas were frozen to the column surface wall as the hydrogen gas flow rate increased. Results from the measured temperatures and pressures will form a benchmark that will be used to judge future heattransfer enhancements to the prototype CVC and to develop a computational fluid dynamicmodel that will help develop design parameters for the full-scale CVC.

Duckworth, Robert C [ORNL; Baylor, Larry R [ORNL; Meitner, Steven J [ORNL; Combs, Stephen Kirk [ORNL; Rasmussen, David A [ORNL; Edgemon, Timothy D [ORNL; Hechler, Michael P [ORNL; Barbier, Charlotte N [ORNL; Pearce, R.J.H. [ITER Organization, Cadarache, France; Kersevan, R. [ITER Organization, Cadarache, France; Dremel, M. [ITER Organization, Cadarache, France; Boissin, Jean Claude [Consultant

2012-01-01

341

An iterative compensation approach without linearization of projector responses for multiple-projector system.  

PubMed

We aim to realize a new and simple compensation method that robustly handles multiple-projector systems without recourse to the linearization of projector response functions. We introduce state equations, which distribute arbitrary brightness among the individual projectors, and control the state equations according to the feedback from a camera. By employing the color-mixing matrix with gradient of projector responses, we compensate the controlled brightness input to each projector. Our method dispenses with cooperation among multiple projectors as well as time-consuming photometric calibration. Compared with existing methods, our method is shown to offer superior compensation performance and a more effective way of compensating multiple-projector systems. PMID:24760905

Miyagawa, Isao; Sugaya, Yoshiko; Arai, Hiroyuki; Morimoto, Masashi

2014-06-01

342

ADSM-an automated distribution system modeling tool for engineering analyses  

Microsoft Academic Search

Designing and operating the distribution system efficiently and economically requires distribution engineers to perform various analytical studies frequently. The system models for these analyses are derived from the information residing in diverse utility databases. One major problem in utilizing these databases is the data mismatch due to different software specifications and hardware platforms. This means additional effort is required to

X.-G. Wei; Z. Sumic; S. S. Venkata

1994-01-01

343

ADSM-an automated distribution system modeling tool for engineering analyses  

Microsoft Academic Search

Designing and operating the distribution system efficiently and economically requires distribution engineers to perform various analytical studies frequently. The system models for these analyses are derived from the information residing in diverse utility databases. One major problem in utilizing these databases is the data mismatch due to different software specifications and hardware platforms. This means additional effort is required to

X.-G. Wei; Z. Sumic; S. S. Venkata

1995-01-01

344

A systems approach to analysing environmental decisions in the automotive industry  

Microsoft Academic Search

This paper uses systems thinking to analyse environmental decisions and their interactions in the automotive industry. The motivation comes from the findings of an environmental decision making investigation undertaken from 2006 to 2010. Using data from 10 case companies, five principles of systems thinking theory were identified in a visual pattern analysis to undertake the assessment by considering the soft

Breno Nunes; Frederick Betz; David Bennett; Duncan Shaw

2011-01-01

345

Non-Iterative Method for Modeling Systematic Data Errors in Power System Risk Assessment  

Microsoft Academic Search

This paper provides a new framework for modeling uncertainty in the input data for power system risk calculations, and the error bars that this places on the results. Differently from previous work, systematic error in unit availability probabilities is considered as well as random error, and a closed-form expres- sion is supplied for the error bars on the results. This

Chris J. Dent; Janusz. W. Bialek

2011-01-01

346

Non-iterative method for modelling systematic data errors in power system risk assessment  

Microsoft Academic Search

Summary form only given. This paper provides a new framework for modelling uncertainty in the input data for power system risk calculations, and the error bars that this places on the results. Differently from previous work, systematic error in unit availability probabilities is considered as well as random error, and a closed-form expression is supplied for the error bars on

C. Dent; J. Bialek

2010-01-01

347

Iterative methods for large scale nonlinear and linear systems. Final report, 1994--1996.  

National Technical Information Service (NTIS)

The major goal of this research has been to develop improved numerical methods for the solution of large-scale systems of linear and nonlinear equations, such as occur almost ubiquitously in the computational modeling of physical phenomena. In addition to...

H. F. Walker

1997-01-01

348

Performance of the Scattering Matrix Arc Detection System on the JET ITER-like ICRF antenna  

Microsoft Academic Search

Ion Cyclotron Radio Frequency (ICRF) antennas operating under high voltage to couple high power to fusion plasmas are at risk of electrical arcing. The standard Voltage Standing Wave Ratio (VSWR) system does not protect low impedance areas, which are used in antennas to achieve load tolerance to variations in plasma loading during Edge Localised Modes (ELMs). The Scattering Matrix Arc

M. Vrancken; E. Lerche; T. Blackman; F. Durodié; M. Evrard; M. Graham; P. Jacquet; A. Kaye; M.-L. Mayoral; M. P. S. Nightingale; J. Ongena; D. Van Eester; M. Van Schoor

2011-01-01

349

New iterative algorithm for algebraic Riccati equation related to H ? control problem of singularly perturbed systems  

Microsoft Academic Search

We present the solution to the algebraic Riccati equation (ARE) with indefinite sign quadratic term related to the H? control problem for singularly perturbed systems by means of a Kleinman type algorithm. The resulting algorithm is very efficient from the numerical point of view because the ARE is solvable even if the quadratic term has an indefinite sign. Moreover, the

Hiroaki Mukaidani; Hua Xu; Koichi Mizukami

2001-01-01

350

SCALP: an iterative-improvement-based low-power data path synthesis system  

Microsoft Academic Search

In this paper, we present SCALP, a comprehensive low-power data path synthesis system that performs the various high-level synthesis tasks (transformations, scheduling, clock selection, module selection, and hardware allocation and assignment) with an aim of reducing the power consumption in the synthesized data path. Focusing on only one or a small subset of the high-level synthesis tasks makes it difficult

Anand Raghunathan; Niraj K. Jha

1997-01-01

351

Iterative detection for imaging page-oriented optical data storage systems  

NASA Astrophysics Data System (ADS)

Imaging page-oriented optical data storage, with its high bit packing density and many parallel readout channels, offers a solution for high capacity data storage with fast data transfer rate. As in any data storage system, increasing the packing density increases the effect of inter-symbol interference (ISI) and inter-page interference (IPI). We describe a combination of modulation encoding/decoding and error correction that overcomes this interference allowing high packing density in the presence of noise while maintaining acceptable bit error rate (BER). We also describe an extension of the algorithm to multi-level (grayscale) encoding.

Intharasombat, Nopparit; Ho, Tawei; Sawchuk, Alexander A.

2006-01-01

352

Integrating cognitive analyses in a large-scale system design process  

Microsoft Academic Search

This paper describes the integration of cognitive analysis into the early stages of design of a new, large-scale system—a next generation US Navy Surface combatant. Influencing complex system designs in ways cognizant of human–system integration principles requires work products that are timely and tightly coupled to other elements of the design process. Because analyses were conducted simultaneously with the design

Ann M. Bisantz; Emilie M. Roth; Bart Brickman; Laura Lin Gosbee; Larry Hettinger; James Mckinney

2003-01-01

353

Upper bounds for convergence rates of vector extrapolation methods on linear systems with initial iterations. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

The application of the minimal polynomial extrapolation (MPE) and the reduced rank extrapolation (RRE) to a vector sequence obtained by the linear iterative technique x(sub j) + 1 = Ax(sub j) = b,j = 1,2,..., is considered. Both methods produce a two dimensional array of approximations s(sub n,k) to the solution of the system (I - A)x = b. Here, s(sub n,k) is obtained from the vectors x(sub j), n is less than or equal to j is less than or equal to n + k + 1. It was observed in an earlier publication by the first author that the sequence s(sub n,k), k = 1,2,..., for n greater than 0, but fixed, possesses better convergence properties than the sequence s(sub 0,k), k = 1,2,.... A detailed theoretical explanation for this phenomenon is provided in the present work. This explanation is heavily based on approximations by incomplete polynomials. It is demonstrated by numerical examples when the matrix A is sparse that cycling with s(sub n,k) for n greater than 0, but fixed, produces better convergence rates and costs less computationally than cycling with s(sub 0,k). It is also illustrated numerically with a convection-diffusion problem that the former may produce excellent results where the latter may fail completely. As has been shown in an earlier publication, the results produced by s(sub 0,k) are identical to the corresponding results obtained by applying the Arnoldi method or generalized minimal residual scheme (GMRES) to the system (I - A)x = b.

Sidi, Avram; Shapira, Yair

1992-01-01

354

Some results from the second iteration of total-system performance assessment for Yucca Mountain  

SciTech Connect

The second preliminary total-system performance assessment for the potential radioactive-waste-repository site at Yucca Mountain has recently been completed. This paper summarizes results for nominal aqueous and gaseous releases using the composite-porosity flow model. The results are found to be sensitive to the type of unsaturated-zone flow, to percolation flux and climate change, to saturated-zone dilution, to container-wetting processes and container-corrosion processes, to fuel-matrix alteration rate and radionuclide solubilities (especially for {sup 237}Np), and to bulk permeability and retardation of gaseous {sup 14}C. These are areas that should be given priority in the site-characterization program. Specific recommendations are given in the full report of the study.

Wilson, M.L.

1994-05-01

355

Development of neutron measurement system for nd/nt fuel ratio measurement in ITER experiments  

NASA Astrophysics Data System (ADS)

The possibility of measurement of fuel ratio from the DT/DD reaction ratio with a neutron spectrometer in the International Thermonuclear Experimental Reactor was studied. The results of neutron transport calculations using the Monte Carlo N-particle [MCNP, a general Monte Carlo N-particle transport code, version 4C, LA-13709, edited by J. F. Briesmeister, Los Alamos National Laboratory, 2000] code system indicated the possibility of DD spectrum separation from the scattered/energy-degraded neutrons derived from DT neutrons by selection of the measurement location and collimator design. A time-of-flight spectrometer was used in this study. An experiment using DD and DT neutrons from an accelerator was conducted at the Japan Atomic Energy Agency Fusion Neutronics Source facility. Using a sophisticated circuit with three discriminators for the first detector, separation of DD and DT neutron components of the spectrum in the megahertz region was confirmed experimentally.

Okada, K.; Kondo, K.; Sato, S.; Nishitani, T.; Nomura, K.; Okamoto, A.; Iwasaki, T.; Kitajima, S.; Sasao, M.

2006-10-01

356

Development and irradiation test of lost alpha detection system for ITER  

NASA Astrophysics Data System (ADS)

We developed a lost alpha detection system to use in burning plasma experiments. The scintillators of Ag:ZnS and polycrystalline Ce:YAG were designed for a high-temperature environment, and the optical transmission line was designed to transmit from the scintillator to the port plug. The required optical components of lenses and mirrors were irradiated using the fission reactor with the initial result that there was no clear change after the irradiation with a neutron flux of 9.6×1017 nm-2 s-1 for 48 h. We propose a diagnostic of alpha particle loss, so-called alpha particle induced gamma ray spectroscopy. The initial laboratory test has been carried out by the use of the Ce doped Lu2SiO5 scintillator detector and an Am-Be source to detect the 4.44 MeV high energy gamma ray due to the 9Be(?,n?)12C reaction.

Nishiura, M.; Nagasaka, T.; Fujioka, K.; Fujimoto, Y.; Tanaka, T.; Ido, T.; Yamamoto, S.; Kashiwa, S.; Sasao, M.

2010-10-01

357

Combining multicriteria decision aid and system dynamics for the control of socio-economic processes. An iterative real-time procedure  

Microsoft Academic Search

The paper presents the elements of a new methodology to control complex and hypercomplex socio-economic struc- tures. The control process is iterative, combining the principles of System Dynamics, Control theory and the PROME- THEE Multicriteria Decision Aid (MCDA) methodology. It consists of three main stages: setting up and calibration of a quantitative model, definition of long-term strategies and short-term control.

J. P. Brans; C. Macharis; P. L. Kunsch; A. Chevalier; M. Schwaninger

2010-01-01

358

Combining multicriteria decision aid and system dynamics for the control of socio-economic processes. An iterative real-time procedure  

Microsoft Academic Search

The paper presents the elements of a new methodology to control complex and hypercomplex socio-economic structures. The control process is iterative, combining the principles of System Dynamics, Control theory and the PROMETHEE Multicriteria Decision Aid (MCDA) methodology. It consists of three main stages: setting up and calibration of a quantitative model, definition of long-term strategies and short-term control. The purpose

J. P. Brans; C. Macharis; P. L. Kunsch; A. Chevalier; M. Schwaninger

1998-01-01

359

Evaluation of Clipping Based Iterative PAPR Reduction Techniques for FBMC Systems  

PubMed Central

This paper investigates filter bankmulticarrier (FBMC), a multicarrier modulation technique exhibiting an extremely low adjacent channel leakage ratio (ACLR) compared to conventional orthogonal frequency division multiplexing (OFDM) technique. The low ACLR of the transmitted FBMC signal makes it especially favorable in cognitive radio applications, where strict requirements are posed on out-of-band radiation. Large dynamic range resulting in high peak-to-average power ratio (PAPR) is characteristic of all sorts of multicarrier signals. The advantageous spectral properties of the high-PAPR FBMC signal are significantly degraded if nonlinearities are present in the transceiver chain. Spectral regrowth may appear, causing harmful interference in the neighboring frequency bands. This paper presents novel clipping based PAPR reduction techniques, evaluated and compared by simulations and measurements, with an emphasis on spectral aspects. The paper gives an overall comparison of PAPR reduction techniques, focusing on the reduction of the dynamic range of FBMC signals without increasing out-of-band radiation. An overview is presented on transmitter oriented techniques employing baseband clipping, which can maintain the system performance with a desired bit error rate (BER).

Kollar, Zsolt

2014-01-01

360

Evaluation of clipping based iterative PAPR reduction techniques for FBMC systems.  

PubMed

This paper investigates filter bankmulticarrier (FBMC), a multicarrier modulation technique exhibiting an extremely low adjacent channel leakage ratio (ACLR) compared to conventional orthogonal frequency division multiplexing (OFDM) technique. The low ACLR of the transmitted FBMC signal makes it especially favorable in cognitive radio applications, where strict requirements are posed on out-of-band radiation. Large dynamic range resulting in high peak-to-average power ratio (PAPR) is characteristic of all sorts of multicarrier signals. The advantageous spectral properties of the high-PAPR FBMC signal are significantly degraded if nonlinearities are present in the transceiver chain. Spectral regrowth may appear, causing harmful interference in the neighboring frequency bands. This paper presents novel clipping based PAPR reduction techniques, evaluated and compared by simulations and measurements, with an emphasis on spectral aspects. The paper gives an overall comparison of PAPR reduction techniques, focusing on the reduction of the dynamic range of FBMC signals without increasing out-of-band radiation. An overview is presented on transmitter oriented techniques employing baseband clipping, which can maintain the system performance with a desired bit error rate (BER). PMID:24558338

Kollár, Zsolt; Varga, Lajos; Horváth, Bálint; Bakki, Péter; Bitó, János

2014-01-01

361

Development and irradiation test of lost alpha detection system for ITER  

SciTech Connect

We developed a lost alpha detection system to use in burning plasma experiments. The scintillators of Ag:ZnS and polycrystalline Ce:YAG were designed for a high-temperature environment, and the optical transmission line was designed to transmit from the scintillator to the port plug. The required optical components of lenses and mirrors were irradiated using the fission reactor with the initial result that there was no clear change after the irradiation with a neutron flux of 9.6x10{sup 17} nm{sup -2} s{sup -1} for 48 h. We propose a diagnostic of alpha particle loss, so-called alpha particle induced gamma ray spectroscopy. The initial laboratory test has been carried out by the use of the Ce doped Lu{sub 2}SiO{sub 5} scintillator detector and an Am-Be source to detect the 4.44 MeV high energy gamma ray due to the {sup 9}Be({alpha},n{gamma}){sup 12}C reaction.

Nishiura, M.; Nagasaka, T.; Tanaka, T.; Ido, T. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Fujioka, K.; Fujimoto, Y. [ILE, Osaka University, 2-6 Yamada oka, Suita 565-0871 (Japan); Yamamoto, S. [Kyoto University, Gokasho Uji, Kyoto 611-0011 (Japan); Kashiwa, S.; Sasao, M. [Tohoku University, Aoba 6-01-2, Sendai 980-8579 (Japan)

2010-10-15

362

Efficient decentralized iterative learning tracker for unknown sampled-data interconnected large-scale state-delay system with closed-loop decoupling property.  

PubMed

In this paper, an efficient decentralized iterative learning tracker is proposed to improve the dynamic performance of the unknown controllable and observable sampled-data interconnected large-scale state-delay system, which consists of N multi-input multi-output (MIMO) subsystems, with the closed-loop decoupling property. The off-line observer/Kalman filter identification (OKID) method is used to obtain the decentralized linear models for subsystems in the interconnected large-scale system. In order to get over the effect of modeling error on the identified linear model of each subsystem, an improved observer with the high-gain property based on the digital redesign approach is developed to replace the observer identified by OKID. Then, the iterative learning control (ILC) scheme is integrated with the high-gain tracker design for the decentralized models. To significantly reduce the iterative learning epochs, a digital-redesign linear quadratic digital tracker with the high-gain property is proposed as the initial control input of ILC. The high-gain property controllers can suppress uncertain errors such as modeling errors, nonlinear perturbations, and external disturbances (Guo et al., 2000) [18]. Thus, the system output can quickly and accurately track the desired reference in one short time interval after all drastically-changing points of the specified reference input with the closed-loop decoupling property. PMID:21872855

Tsai, Jason Sheng-Hong; Chen, Fu-Ming; Yu, Tze-Yu; Guo, Shu-Mei; Shieh, Leang-San

2012-01-01

363

Iterative Magnetometer Calibration  

NASA Technical Reports Server (NTRS)

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.

Sedlak, Joseph

2006-01-01

364

The Impact of British Airways Wind Observations on the Goddard Earth Observing System Analyses and Forecasts  

NASA Technical Reports Server (NTRS)

British Airways flight data recorders can provide valuable meteorological information, but they are not available in real-time on the Global Telecommunication System. Information from the flight recorders was used in the Global Aircraft Data Set (GADS) experiment as independent observations to estimate errors in wind analyses produced by major operational centers. The GADS impact on the Goddard Earth Observing System Data Assimilation System (GEOS DAS) analyses was investigated using GEOS-1 DAS version. Recently, a new Data Assimilation System (fvDAS) has been developed at the Data Assimilation Office, NASA Goddard. Using fvDAS , the, GADS impact on analyses and forecasts was investigated. It was shown the GADS data intensify wind speed analyses of jet streams for some cases. Five-day forecast anomaly correlations and root mean squares were calculated for 300, 500 hPa and SLP for six different areas: Northern and Southern Hemispheres, North America, Europe, Asia, USA These scores were obtained as averages over 21 forecasts from January 1998. Comparisons with scores for control experiments without GADS showed a positive impact of the GADS data on forecasts beyond 2-3 days for all levels at the most areas.

Rukhovets, Leonid; Sienkiewicz, M.; Tenenbaum, J.; Kondratyeva, Y.; Owens, T.; Oztunali, M.; Atlas, Robert (Technical Monitor)

2001-01-01

365

Accelerator-Driven Systems Neutronic Analyses at ENEA and Politecnico di Torino  

Microsoft Academic Search

A growing interest in accelerator-driven systems (ADSs) has led to the establishment in Italy of a basic research and development program aimed at the study of the physics and technological development needed to design an ADS for nuclear waste transmutation. In the framework of this program, ENEA and Politecnico di Torino are carrying out some neutronic analyses focused on an

M. Carta; K. W. Burn; A. DAngelo; V. Peluso; P. Ravetto

1999-01-01

366

A System and Language for Building System-Specific, Static Analyses  

Microsoft Academic Search

This paper presents a novel approach to bug-finding analysis and an implementation of that approach. Our goal is to find as many serious bugs as possible. To do so, we designed a flexible, easy-to-use extension language for specifying analyses and an efficent algorithm for executing these extensions. The language, , executes these analyses efficiently using a context-sensitive, interprocedural analysis. Our

Seth Hallem; Benjamin Chelf; Yichen Xie; Dawson R. Engler

2002-01-01

367

Use of simulation models to evaluate irrigation performance including water productivity, risk and system analyses  

Microsoft Academic Search

Worsening water scarcity will increase pressure to use water more productively. In the classical view of irrigation research,\\u000a some important aspects are often ignored: the total water balance approach, productivity of water, food security, and irrigation-system\\u000a level analyses. These four approaches were evaluated using a detailed agro-hydrological model applied to an irrigation system\\u000a in western Turkey. Emphasis was placed on

Peter Droogers; Geoff Kite; Hammond Murray-Rust

2000-01-01

368

Statistical analyses to support forensic interpretation for a new ten-locus STR profiling system  

Microsoft Academic Search

A new ten-locus STR (short tandem repeat) profiling system was recently introduced into casework by the Forensic Science\\u000a Service (FSS) and statistical analyses are described here based on data collected using this new system for the three major\\u000a racial groups of the UK: Caucasian, Afro-Caribbean and Asian (of Indo-Pakistani descent). Allele distributions are compared\\u000a and the FSS position with regard

L. A. Foreman; I. W. Evett

2001-01-01

369

Particle Beam Application —Present Status and Future Prospective 2.Neutral Particle Beams for Plasma Heating in Magnetic Confinement System 2.2 Neutral Beam Injectors for ITER and Tokamak Fusion Reactors  

NASA Astrophysics Data System (ADS)

In ITER, neutral beam (NB) heating and current drive (H&CD) system fires energetic particle beams of 1 MeV, 33 MW (16.5 MW/NB injector) into the fusion plasma. The design allows late installation of the third NB injector for upgrade in current drive experiment toward steady state operation. The ITER NB system has been designed to fulfill the requirements of the plasma physics, considering advanced scenario achieved with off-axis CD by NB. A design overview of the ITER NB H&CD system is described. The paper also reports the recent R&D status of ion source and accelerator, as key components of the NB system, toward ITER construction. The NB H&CD performance required in future tokamak reactors is discussed together with the necessary R&D issues.

Inoue, Takashi

370

Preparing ITER ICRF: development and analysis of the load resilient matching systems based on antenna mock-up measurements  

Microsoft Academic Search

The reference design for the ICRF antenna of ITER is constituted by a tight array of 24 straps grouped in eight triplets. The matching network must be load resilient for operation in ELMy discharges and must have antenna spectrum control for heating or current drive operation. The load resilience is based on the use of either hybrid couplers or conjugate-T

A. Messiaen; M. Vervier; P. Dumortier; D. Grine; P. U. Lamalle; F. Durodié; R. Koch; F. Louche; R. Weynants

2009-01-01

371

Particle Beam Application Present Status and Future Prospective 2.Neutral Particle Beams for Plasma Heating in Magnetic Confinement System 2.2 Neutral Beam Injectors for ITER and Tokamak Fusion Reactors  

Microsoft Academic Search

In ITER, neutral beam (NB) heating and current drive (H&CD) system fires energetic particle beams of 1 MeV, 33 MW (16.5 MW\\/NB injector) into the fusion plasma. The design allows late installation of the third NB injector for upgrade in current drive experiment toward steady state operation. The ITER NB system has been designed to fulfill the requirements of the

Takashi Inoue

2002-01-01

372

Fully automated, four-column capillary LC-MS system for maximizing throughput in proteomic analyses  

PubMed Central

We describe a 4-column, high-pressure capillary liquid chromatography (LC) system for robust, high-throughput LC-MS(/MS) analyses. This system performs multiple LC separations in parallel, but staggers each of them such that the data-rich region of each separation is sampled sequentially. By allowing nearly continuous data acquisition, this design maximizes the use of the mass spectrometer. Each analytical column is connected to a corresponding ESI emitter in order to avoid the use of post-column switching and associated dead volume issues. Encoding translation stages are employed to sequentially position the emitters at the MS inlet. The high reproducibility of this system is demonstrated using consecutive analyses of global tryptic digest of the microbe Shewanella oneidensis.

Livesay, Eric A.; Tang, Keqi; Taylor, Beverley K.; Buschbach, Michael A.; Hopkins, Derek F.; LaMarche, Brian L.; Zhao, Rui; Shen, Yufeng; Orton, Daniel J.; Moore, Ronald J.; Kelly, Ryan T.; Udseth, Harold R.; Smith, Richard D.

2008-01-01

373

Conceptual design of fusion experimental reactor (FER/ITER)  

NASA Astrophysics Data System (ADS)

Conceptual design of the Ion Cyclotron Wave (ICW) system for the FER and the Japanese contribution to the conceptual design of the International Thermonuclear Experimental Reactor (ITER) Ion Cyclotron Wave (ICW) system are presented. A frequency range of the FER ICW system is 50-85 MHz, which covers 2 omega (sub cT) heating, current drive by transit time magnetic pumping (TTMP) and 2 omega (sub cD) heating. Physics analyses show that the FER and the ITER ICW systems are suitable for the central ion heating and the burn control. The launching systems of the FER ICW system and the ITER high frequency ICW system are characterized by in-port plug and ridged-waveguide-fed 5x4 phased loop array. Merits of those systems are (1) a ceramic support is not necessary inside the cryostat and (2) remote maintenance of the front end part of the launcher is relatively easy. Overall structure of the launching system is consistent with radiation shielding, cooling, pumping, tritium safety and remote maintenance. The launcher has injection capability of 20 MW in the frequency range of 50-85 MHz with the separatrix-antenna distance of 15 cm and steep scrape-off density profile of H-mode. The shape of the ridged waveguide is optimized to provide desired frequency range and power handling capability with a finite element method. Matching between the current strap and the ridged waveguide is satisfactorily good. Thermal analysis of the Faraday shield shows that high electric conductivity low Z material such as beryllium should be chosen for a protection tile of the Faraday shield. A thick Faraday shield is necessary to tolerate electromagnetic force during disruptions. R and D needs for the ITER/FER ICW systems are identified and gain from JT-60/60U ICRF experiments and operations are indicated in connection with them.

Kimura, Haruyuki; Saigusa, Mikio; Saitoh, Yasushi

1991-06-01

374

Iterative clipping and filtering based on discrete cosine transform/inverse discrete cosine transform for intensity modulator direct detection optical orthogonal frequency division multiplexing system  

NASA Astrophysics Data System (ADS)

Iterative clipping and filtering (ICF) is a useful technique to reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals. However, the classical ICF with Fast Fourier Transform/Inverse Fast Fourier Transform requires much iteration to approach a specified PAPR threshold in the complementary cumulative distribution function. To reduce the nonlinear distortion in both electrical and optical devices and in the optical fiber, we propose a novel ICF based on discrete cosine transform/inverse discrete cosine transform to reduce the PAPR in an intensity modulator and direct detection (IM/DD) optical OFDM system. Furthermore, the new technique considerably improves bit error rate (BER) and reduces the PAPR with just few iterations. The experimental results show that the receiver sensitivity at a BER of 1 for a 2.5-Gbytes/s OFDM signal and after 200-km standard single-mode fiber transmission has been improved by 1.1, 2.3, and 3.6 dBm with launch powers of 6, 8, and 12 dBm respectively.

Mangone, Fall; Tang, Jin; Chen, Ming; Xiao, Jiangnan; Fan, Li; Chen, Lin

2013-06-01

375

Iterated sequential transducers as language generating devices  

Microsoft Academic Search

Iterated finite state sequential transducers are considered as language generating devices. The hierarchy induced by the size of the state alphabet is proved to collapse to the fourth level. The corresponding language families are related to the families of languages generated by Lindenmayer systems and Chomsky grammars. Finally, some results on deterministic and extended iterated finite state transducers are established.

Henning Bordihn; Henning Fernau; Markus Holzer; Vincenzo Manca; Carlos Martín-vide

2006-01-01

376

Design Proposal for the ITER Feeder Busbars  

Microsoft Academic Search

Based on the functional specification by the ITER organization, CRPP developed a design proposal for the ITER magnet feeder busbar system. The magnetic field level estimated for the operation of the busbars allows the use of NbTi superconductor. The minimum superconducting cross sections and copper stabilizers are calculated based on a temperature margin of 2.5 K and a safe hot

Marco Calvi; Pierre Bauer; Denis Bessette; Francesca Cau; Claudio Marinucci; Pierluigi Bruzzone

2010-01-01

377

Portable, fully autonomous, ion chromatography system for on-site analyses.  

PubMed

The basic operating principles of a portable, fully autonomous, ion chromatography system are described. The system affords the user the ability to collect and analyze samples continuously for 27 days, or about 1930 injections before needing any user intervention. Within the 13kg system, is a fully computer controlled autosampling, chromatography and data acquisition system. An eluent reflux device (ERD), which integrates eluent suppression and generation in a single multi-chambered device, is used to minimize eluent consumption. During operation, about 1?L of water per minute is lost to waste while operating standard-bore chromatography at 0.5mLmin(-1) due to eluent refluxing. Over the course of 27 days, about 100mL of rinse water is consumed, effectively eliminating waste production. Data showing the reproducibility (below 1% relative standard deviation over 14 days) of the device is also presented. Chromatographic analyses of common anions (Cl(-), NO3(-), SO4(2-), PO4(3-)), is accomplished in under 15min using a low backpressure guard column with ?25mM KOH isocratic elution. For detection, a small capacitively-coupled contactless conductivity detector (C4D) is employed, able to report analytes in the sub to low micromolar range. Preconcentration of the injected samples gives a 50-fold decrease in detection limits, primarily utilized for in-situ detection of phosphate (LOQ 10?gL(-1)). Field analyses are shown for multiple on-site analyses of stream water indifferent weather conditions. PMID:24913366

Elkin, Kyle R

2014-07-25

378

Analyses of Markov Decision Process Structure Regarding the Possible Strategic use of Interacting Memory Systems  

PubMed Central

Behavioral tasks are often used to study the different memory systems present in humans and animals. Such tasks are usually designed to isolate and measure some aspect of a single memory system. However, it is not necessarily clear that any given task actually does isolate a system or that the strategy used by a subject in the experiment is the one desired by the experimenter. We have previously shown that when tasks are written mathematically as a form of partially observable Markov decision processes, the structure of the tasks provide information regarding the possible utility of certain memory systems. These previous analyses dealt with the disambiguation problem: given a specific ambiguous observation of the environment, is there information provided by a given memory strategy that can disambiguate that observation to allow a correct decision? Here we extend this approach to cases where multiple memory systems can be strategically combined in different ways. Specifically, we analyze the disambiguation arising from three ways by which episodic-like memory retrieval might be cued (by another episodic-like memory, by a semantic association, or by working memory for some earlier observation). We also consider the disambiguation arising from holding earlier working memories, episodic-like memories or semantic associations in working memory. From these analyses we can begin to develop a quantitative hierarchy among memory systems in which stimulus-response memories and semantic associations provide no disambiguation while the episodic memory system provides the most flexible disambiguation, with working memory at an intermediate level.

Zilli, Eric A.; Hasselmo, Michael E.

2008-01-01

379

Real options based iterative development program metrics  

US Patent & Trademark Office Database

Embodiments of the present invention address deficiencies of the art in respect to iterative project management and provide a method, system and computer program product for utilizing real options based iterative development program metrics. In an embodiment of the invention, a data processing system configured for software project management can include a computer aided software engineering tool enabled to use a methods architecture configured to manage iterative development, said as Rational Unified Process (TM) (RUP) methodware. The data processing system also can include a data store of unified process data produced by the computer aided software engineering tool. Finally, the data processing system can include real options-based computational logic.

2009-06-09

380

Economic analyses of absorption systems: Part A—Design and cost evaluation  

Microsoft Academic Search

Economic analyses of absorption system components have been conducted with the aim to optimize the various operating parameters. The absorber, condenser, evaporator, generator, rectifier, precooler and preheater have been designed using standard procedures, and their costs have been estimated based upon the materials used, fabrication installation and overhead charges. Four types of refrigerant-absorbent combinations (H2O-LiBr, NH3-H2O, NH3-NaSCN and NH3-LiNO3) using

M. Altamush Siddiqui

1997-01-01

381

ACCIDENT ANALYSES & CONTROL OPTIONS IN SUPPORT OF THE SLUDGE WATER SYSTEM SAFETY ANALYSIS  

Microsoft Academic Search

This report documents the accident analyses and nuclear safety control options for use in Revision 7 of HNF-SD-WM-SAR-062, ''K Basins Safety Analysis Report'' and Revision 4 of HNF-SD-SNF-TSR-001, ''Technical Safety Requirements - 100 KE and 100 KW Fuel Storage Basins''. These documents will define the authorization basis for Sludge Water System (SWS) operations. This report follows the guidance of DOE-STD-3009-94,

2003-01-01

382

Preliminary Design and Analysis of the DC Reactor for the ITER Converter  

NASA Astrophysics Data System (ADS)

The DC reactor is an important piece of equipment for restraining loop and ripple currents in the international thermonuclear experimental reactor (ITER) converter power supply system. As the reactor is operated at a steady state of 27.5 kA and needs to withstand a peak current of 175 kA, so the design of the DC reactor used in the ITER converter power supply system is necessary. A new water-cooling dry-type air-core reactor is designed in this work. The detailed structural parameters are calculated by theoretical formulas, and then the structure is optimized by electromagnetic simulation with ANSYS. Finally, thermal and dynamic stability analyses are performed to verify the temperature and stress at a rated current of 27.5 kA and pulsed current of 175 kA. The analysis results show that the temperature and stress meet the requirements of the ITER converter power supply system.

Yang, Ning; Zhang, Ming; Li, Chuan; Song, Zhiquan; Yu, Kexun; Zhuang, Ge; Xu, Tao

2014-03-01

383

Summary report for ITER Task-T19: MHD pressure drop and heat transfer study for liquid metal systems  

SciTech Connect

A key feasibility issue for the ITER Vanadium/Lithium breeding blanket is the question of insulator coatings. Design calculations show that an electrically insulating layer is necessary to maintain an acceptably low MHD pressure drop. To begin experimental investigations of the MHD performance of candidate insulator materials and the technology for putting them in place, a new test section was prepared. Aluminum oxide was chosen as the first candidate insulating material because it may be used in combination with NaK in the ITER vacuum vessel and/or the divertor. Details on the methods used to produce the aluminum oxide layer as well as the microstructures of the coating and the aluminide sublayer are presented and discussed. The overall MHD pressure drop, local MHD pressure gradient, local transverse MHD pressure difference, and surface voltage distributions in both the circumferential and the axial directions are reported and discussed. The positive results obtained here for high-temperature NaK have two beneficial implications for ITER. First, since NaK may be used in the vacuum vessel and/or the divertor, these results support the design approach of using electrically insulating coatings to substantially reduce MHD pressure drop. Secondly, while Al{sub 2}O{sub 3}/SS is not the same coating/base material combination which would be used in the advanced blanket, this work nonetheless shows that it is possible to produce a viable insulating coating which is stable in contact with a high temperature alkali metal coolant.

Reed, C.B.; Hua, T.Q.; Natesan, K. [Argonne National Lab., IL (United States); Kirillov, I.R.; Vitkovski, I.V.; Anisimov, A.M. [D.V. Efremov Scientific Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation). MHD-Machines Lab.

1995-03-01

384

Solar power satellite system definition study. Volume 7, phase 1: SPS and rectenna systems analyses  

NASA Technical Reports Server (NTRS)

A systems definition study of the solar power satellite systems is presented. The design and power distribution of the rectenna system is discussed. The communication subsystem and thermal control characteristics are described and a failure analysis performed on the systems is reported.

1979-01-01

385

System design analyses of a rotating advanced-technology space station for the year 2025  

NASA Technical Reports Server (NTRS)

Studies of an advanced technology space station configured to implement subsystem technologies projected for availability in the time period 2000 to 2025 is documented. These studies have examined the practical synergies in operational performance available through subsystem technology selection and identified the needs for technology development. Further analyses are performed on power system alternates, momentum management and stabilization, electrothermal propulsion, composite materials and structures, launch vehicle alternates, and lunar and planetary missions. Concluding remarks are made regarding the advanced technology space station concept, its intersubsystem synergies, and its system operational subsystem advanced technology development needs.

Queijo, M. J.; Butterfield, A. J.; Cuddihy, W. F.; Stone, R. W.; Wrobel, J. R.; Garn, P. A.; King, C. B.

1988-01-01

386

Analyses of the dynamic docking test system for advanced mission docking system test programs. [Apollo Soyuz Test Project  

NASA Technical Reports Server (NTRS)

Results are given of analytical studies performed in support of the design, implementation, checkout and use of NASA's dynamic docking test system (DDTS). Included are analyses of simulator components, a list of detailed operational test procedures, a summary of simulator performance, and an analysis and comparison of docking dynamics and loads obtained by test and analysis.

Gates, R. M.; Williams, J. E.

1974-01-01

387

An evaluation system for electronic retrospective analyses in radiation oncology: implemented exemplarily for pancreatic cancer  

NASA Astrophysics Data System (ADS)

To date, conducting retrospective clinical analyses is rather difficult and time consuming. Especially in radiation oncology, handling voluminous datasets from various information systems and different documentation styles efficiently is crucial for patient care and research. With the example of patients with pancreatic cancer treated with radio-chemotherapy, we performed a therapy evaluation by using analysis tools connected with a documentation system. A total number of 783 patients have been documented into a professional, web-based documentation system. Information about radiation therapy, diagnostic images and dose distributions have been imported. For patients with disease progression after neoadjuvant chemoradiation, we designed and established an analysis workflow. After automatic registration of the radiation plans with the follow-up images, the recurrence volumes are segmented manually. Based on these volumes the DVH (dose-volume histogram) statistic is calculated, followed by the determination of the dose applied to the region of recurrence. All results are stored in the database and included in statistical calculations. The main goal of using an automatic evaluation system is to reduce time and effort conducting clinical analyses, especially with large patient groups. We showed a first approach and use of some existing tools, however manual interaction is still necessary. Further steps need to be taken to enhance automation. Already, it has become apparent that the benefits of digital data management and analysis lie in the central storage of data and reusability of the results. Therefore, we intend to adapt the evaluation system to other types of tumors in radiation oncology.

Kessel, Kerstin A.; Jäger, Andreas; Bohn, Christian; Habermehl, Daniel; Zhang, Lanlan; Engelmann, Uwe; Bougatf, Nina; Bendl, Rolf; Debus, Jürgen; Combs, Stephanie E.

2013-03-01

388

Integrated Process Model Development and Systems Analyses for the LIFE Power Plant  

SciTech Connect

We have developed an integrated process model (IPM) for a Laser Inertial Fusion-Fission Energy (LIFE) power plant. The model includes cost and performance algorithms for the major subsystems of the plant, including the laser, fusion target fabrication and injection, fusion-fission chamber (including the tritium and fission fuel blankets), heat transfer and power conversion systems, and other balance of plant systems. The model has been developed in Visual Basic with an Excel spreadsheet user interface in order to allow experts in various aspects of the design to easily integrate their individual modules and provide a convenient, widely accessible platform for conducting the system studies. Subsystem modules vary in level of complexity; some are based on top-down scaling from fission power plant costs (for example, electric plant equipment), while others are bottom-up models based on conceptual designs being developed by LLNL (for example, the fusion-fission chamber and laser systems). The IPM is being used to evaluate design trade-offs, do design optimization, and conduct sensitivity analyses to identify high-leverage areas for R&D. We describe key aspects of the IPM and report on the results of our systems analyses. Designs are compared and evaluated as a function of key design variables such as fusion target yield and pulse repetition rate.

Meier, W R; Anklam, T; Abbott, R; Erlandson, A; Halsey, W; Miles, R; Simon, A J

2009-07-15

389

SCALE: A modular code system for performing standardized computer analyses for licensing evaluation  

SciTech Connect

This Manual represents Revision 5 of the user documentation for the modular code system referred to as SCALE. The history of the SCALE code system dates back to 1969 when the current Computational Physics and Engineering Division at Oak Ridge National Laboratory (ORNL) began providing the transportation package certification staff at the U.S. Atomic Energy Commission with computational support in the use of the new KENO code for performing criticality safety assessments with the statistical Monte Carlo method. From 1969 to 1976 the certification staff relied on the ORNL staff to assist them in the correct use of codes and data for criticality, shielding, and heat transfer analyses of transportation packages. However, the certification staff learned that, with only occasional use of the codes, it was difficult to become proficient in performing the calculations often needed for an independent safety review. Thus, shortly after the move of the certification staff to the U.S. Nuclear Regulatory Commission (NRC), the NRC staff proposed the development of an easy-to-use analysis system that provided the technical capabilities of the individual modules with which they were familiar. With this proposal, the concept of the Standardized Computer Analyses for Licensing Evaluation (SCALE) code system was born. This manual covers an array of modules written for the SCALE package, consisting of drivers, system libraries, cross section and materials properties libraries, input/output routines, storage modules, and help files.

NONE

1997-03-01

390

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

Microsoft Academic Search

Following an overview of the ITER Ion Cyclotron Resonance Frequency (ICRF) system, the JET ITER-like antenna (ILA) will be described. The ILA was designed to test the following ITER issues: (a) reliable operation at power densities of order 8 MW\\/m2 at voltages up to 45 kV using a close-packed array of straps; (b) powering through ELMs using an internal (in-vacuum)

M. P. S. Nightingale; F. Durodié; A. Argouarch; B. Beaumont; A. Becoulet; J.-M. Bernard; T. Blackman; J. Caughman; P. Dumortier; D. Edwards; J. Fanthome; T. Gassman; R. Goulding; M. Graham; C. Hamlyn-Harris; D. Hancock; S. Huygen; P. Jacquet; F. Kazarian; R. Koch; P. U. Lamalle; E. Lerche; F. Louche; R. Maggiora; M.-L. Mayoral; A. M. Messiaen; D. Milanesio; I. Monakhov; A. Mukherjee; K. Nicholls; J.-M. Noterdaeme; J. Ongena; D. Rasmussen; F. Rimini; R. Sartori; D. Stork; D. van Eester; M. Vervier; M. Vrancken; K. Vulliez; A. Whitehurst; D. Wilson; E. Wooldridge; JET EFDA contributors

2009-01-01

391

A new iterative approach to fractal models  

NASA Astrophysics Data System (ADS)

Mandelbrot is best appreciated for his broad attempt to describe irregular shapes in nature. He founded fractal geometry in 1975. Subsequently the whole fractal theory developed using one-step feedback systems. In 2002, an attempt was made to study and analyze fractal objects using two-step feedback systems. Researchers used superior iteration methods to implement two-step feedback systems. This was the beginning of a new iterative approach in the study of fractal models, and it seems promising to extend fractal theory. The purpose of this paper is to present a review of literature in fractal analysis using this new iterative approach and explore its potential applications.

Singh, S. L.; Mishra, S. N.; Sinkala, W.

2012-02-01

392

The real mission of ITER  

SciTech Connect

For future machines, the plasma stored energy is going up by factors of 20-40x, and plasma currents by 2-3x, while the surface to volume ratio is at the same time decreasing. Therefore the disruption forces, even for constant B, (which scale like IxB), and associated possible localized heating on machine components, are more severe. Notably, Tore Supra has demonstrated removal of more than 1 GJ of input energy, over nearly a 400 second period. However, the instantaneous stored energy in the Tore Supra system (which is most directly related to the potential for disruption damage) is quite small compared to other large tokamaks. The goal of ITER is routinely described as studying DT burning plasmas with a Q {approx} 10. In reality, ITER has a much more important first order mission. In fact, if it fails at this mission, the consequences are that ITER will never get to the eventual stated purpose of studying a burning plasma. The real mission of ITER is to study (and demonstrate successfully) plasma control with {approx}10-17 MA toroidal currents and {approx}100-400 MJ plasma stored energy levels in long-pulse scenarios. Before DT operation is ever given a go-ahead in ITER, the reality is that ITER must demonstrate routine and reliable control of high energy hydrogen (and deuterium) plasmas. The difficulty is that ITER must simultaneously deal with several technical problems: (1) heat removal at the plasma/wall interface, (2) protection of the wall components from off-normal events, and (3) generation of dust/redeposition of first wall materials. All previous tokamaks have encountered hundred's of major disruptions in the course of their operation. The consequences of a few MA of runaway electrons (at 20-50 MeV) being generated in ITER, and then being lost to the walls are simply catastrophic. They will not be deposited globally, but will drift out (up, down, whatever, depending on control system), and impact internal structures, unless 'ameliorated'. Basically, this represents an extraordinarily robust e-beam welding machine, capable of deep penetration into any armor tiles, to the cooling channels which are embedded less than 1 cm below the tile surface. When energy is deposited in a fraction of a second on (or in) a tile, the presence of underlying water cooling does no good for the purposes of heat removal.

Wurden, G A [Los Alamos National Laboratory

2009-01-01

393

Performance Analyses of ECCS and Containment Systems for the 4500 MW ESBWR  

SciTech Connect

GE latest evolution of the Boiling Water Reactor, the ESBWR, is an advanced, 4500 MWth nuclear power plant design, submitted to the NRC for design certification in 2005. This paper presents the key results of performance analyses of ESBWR ECCS and containment systems. The ESBWR is designed to take full advantage of passive features to improve the plant performance and economics. The key features are the use of natural circulation during normal operation and passive safety systems for decay heat removal and inventory control. The use of natural circulation results in relatively taller reactor vessel and more in-vessel coolant inventory. Consequently, the water level always covers the core following an accident, assuring no fuel heatup. The use of passive systems results in simpler safety systems. The peak containment pressure and margin to the design value basically depend on the containment volumes and the water inventories. Additionally, these passive systems impose no significant challenge to the operator. Performance analyses for the 4500 MWth ESBWR were made for a spectrum of LOCA events. These calculations accounted for uncertainties and biases in the computer models and used conservative initial conditions and plant parameters. Results of these performance analyses show that: (1) core remains covered with large margin and there is no core heatup in the ESBWR for any break size, (2) the long-term containment pressure increases gradually with time, in the order of hours, and the peak pressure is below the design value with large margin, and (3) the margins depend on the containment volumes and water inventories. (authors)

Cheung, Y.K.; Shiralkar, B.S.; Marquino, W. [GE Energy, 1989 Little Orchard St., San Jose, CA 95125 (United States)

2006-07-01

394

Real-Time Soils Characterization and Analyses Systems Used at Ohio Closure Sites  

SciTech Connect

The Idaho National Engineering and Environmental Laboratory (INEEL) and the Fernald Environmental Management Project (FEMP) have jointly developed a field-deployed analytical system to rapidly scan, characterize, and analyze surface soil contamination. The basic system consists of a sodium iodide (NaI) spectrometer and global positioning system (GPS) hardware. This hardware can be deployed from any of four different platforms depending on the scope of the survey at hand. These platforms range from a large tractor-based unit (the RTRAK) used to survey large, relatively flat areas to a hand-pushed unit where maneuverability is important, to an excavator mounted system used to scan pits and trenches. The mobile sodium iodide concept was initially developed by the FEMP to provide pre-screening analyses for soils contaminated with uranium, thorium, and radium. The initial study is documented in the RTRAK Applicability Study and provides analyses supporting the field usage of the concept. The RTRAK system produced data that required several days of post-processing and analyses to generate an estimation of field coverage and activity levels. The INEEL has provided integrated engineering, computer hardware and software support to greatly streamline the data acquisition and analysis process to the point where real-time activity and coverage maps are available to the field technicians. On-line analyses have been added to automatically convert GPS data to Ohio State-Plane coordinates, examine and correct collected spectra for energy calibration drifts common to NaI spectrometers, and strip spectra in regions of interest to provide moisture corrected activity levels for total uranium, thorium-232, and radium-226. Additionally, the software provides a number of checks and alarms to alert operators that a hand-examination of spectral data in a particular area may be required. The FEMP has estimated that this technology has produced projected site savings in excess of $34M through FY 2006. Additionally, the INEEL has applied this real-time concept to develop an in-situ platform to detect plutonium-238 in contaminated soils to the 50 pCi/g level. The heart of this system is a large-area proportional counter that collects spectra in the x-ray region. A prototype system was demonstrated at the Mound Environmental Management Project (MEMP) in October of 2002.

Roybal, Lyle Gene; Carpenter, Michael Vance; Giles, John Robert; Hartwell, John Kelvin; Danahy, R.

2003-02-01

395

On numerical solutions of a new coupled MKdV system by using the Adomian decomposition method and He's variational iteration method  

NASA Astrophysics Data System (ADS)

In this paper, we obtain the approximate solution for the soliton solution of a new coupled modified Korteweg-de Vries (MKdV) system with initial conditions by the Adomian decomposition method (ADM) and the variational iteration method (VIM) and then numerical results from the two methods are compared, showing that the ADM leads to more accurate results. Furthermore, the VIM overcomes the difficulty arising when calculating the Adomian polynomials, which is an important advantage over the ADM. The numerical results show that only a few terms are sufficient to obtain accurate solutions.

Inc, Mustafa; Cavlak, Ebru

2008-10-01

396

Opportunities for U.S. Industry in the ITER project  

Microsoft Academic Search

The author discusses the role of industry in the ITER project. In particular, emphasis is placed on preparing US industry to play a role in this program, and to prepare it to bid on construction contracts for either ITER systems, or parts of other development efforts which result from the engineering design study phase of the ITER project which is

Alexander J. Glass

1992-01-01

397

MultiStage Iterative Antenna Training for Millimeter Wave Communications  

Microsoft Academic Search

We study 60 GHz millimeter wave communication systems employing SVD based transmit precoding and receive combining, and propose a multi-stage iterative method in training the antenna coefficients. The antenna training is carried out in multiple stages one after another, while each stage features an iterative process based on the power iteration principle. Null space projection is used as an enabling

Pengfei Xia; Su-khiong Yong; Oh Jisung; Chiu Ngo

2008-01-01

398

Recursive LLR Combining in Iterative Multiuser Decoding of Coded CDMA  

Microsoft Academic Search

Due to the prohibitive complexity of optimal mul- tiuser detection, suboptimal structures are commonly suggested for use in iterative multiuser decoders. The use of suboptimal components in the iterative structure leads to performance losses in terms of system load, bit error rate (BER), and convergence speed. In this paper, we introduce a simple recursive filtering structure into the iterative multiuser

Rob Milner; Lars K. Rasmussen; Fredrik Brannstr

2007-01-01

399

Manned systems utilization analysis (study 2.1). Volume 3: LOVES computer simulations, results, and analyses  

NASA Technical Reports Server (NTRS)

The LOVES computer program was employed to analyze the geosynchronous portion of the NASA's 1973 automated satellite mission model from 1980 to 1990. The objectives of the analyses were: (1) to demonstrate the capability of the LOVES code to provide the depth and accuracy of data required to support the analyses; and (2) to tradeoff the concept of space servicing automated satellites composed of replaceable modules against the concept of replacing expendable satellites upon failure. The computer code proved to be an invaluable tool in analyzing the logistic requirements of the various test cases required in the tradeoff. It is indicated that the concept of space servicing offers the potential for substantial savings in the cost of operating automated satellite systems.

Stricker, L. T.

1975-01-01

400

On the safety of ITER accelerators.  

PubMed

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

Li, Ge

2013-01-01

401

On the safety of ITER accelerators  

PubMed Central

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.

Li, Ge

2013-01-01

402

PCG reference manual: A package for the iterative solution of large sparse linear systems on parallel computers. Version 1.0  

SciTech Connect

PCG (Preconditioned Conjugate Gradient package) is a system for solving linear equations of the form Au = b, for A a given matrix and b and u vectors. PCG, employing various gradient-type iterative methods coupled with preconditioners, is designed for general linear systems, with emphasis on sparse systems such as these arising from discretization of partial differential equations arising from physical applications. It can be used to solve linear equations efficiently on parallel computer architectures. Much of the code is reusable across architectures and the package is portable across different systems; the machines that are currently supported is listed. This manual is intended to be the general-purpose reference describing all features of the package accessible to the user; suggestions are also given regarding which methods to use for a given problem.

Joubert, W.D. [Los Alamos National Lab., NM (United States); Carey, G.F.; Kohli, H.; Lorber, A.; McLay, R.T.; Shen, Y. [Texas Univ., Austin, TX (United States); Berner, N.A. [Texas Univ., Austin, TX (United States)]|[Los Alamos National Lab., NM (United States); Kalhan, A. [Los Alamos National Lab., NM (United States)]|[Tennessee Univ., Knoxville, TN (United States)

1995-01-01

403

The Global/Local Nexus in Comparative Policy Studies: Analysing the Triple Bonus System in Mongolia over Time  

ERIC Educational Resources Information Center

The article analyses a phenomenon that has accompanied teacher salary reform in Mongolia: the import of two global education policies that were nearly identical to the already existing local bonus system ("olympiads"). To make sense of an import that appears superfluous, the author analyses the reception and translation of the triple bonus system

Steiner-Khamsi, Gita

2012-01-01

404

Flight test and analyses of the B-1 structural mode control system at supersonic flight conditions  

NASA Technical Reports Server (NTRS)

A practical structural mode control system (SMCS) that could be turned on at takeoff and be left on for the entire flight was demonstrated. The SMCS appears to be more effective in damping the key fuselage bending modes at supersonic speeds than at the design point of Mach 0.85 (for fixed gains). The SMCS has an adverse effect on high frequency symmetric modes; however, this adverse effect did not make the system unstable and does not appear to affect ride quality performance. The vertical ride quality analyses indicate that the basic configuration without active systems is satisfactory for long term exposure. If clear air turbulence were to be encountered, indications are that the SMCS would be very effective in reducing the adverse accelerations. On the other hand, lateral ride quality analyses indicate that the aircraft with the SMCS on does not quite meet the long term exposure criteria, but would be satisfactory for shot term exposure at altitude. Again, the lateral SMCS was shown to be very effective in reducing peak lateral accelerations.

Wykes, J. H.; Kelpl, M. J.; Brosnan, M. J.

1983-01-01

405

Precursor Systems Analyses of Automated Highway Systems. Carrier Phase GPS for AHS Vehicle Control. Resource Materials.  

National Technical Information Service (NTIS)

This report describs the results of a PSA contract awarded to SRI International to analyze applications of advanced Global Positioning System (GPS) measurement techniques to provide data for lateral and longitudinal control of AHS vehicles. The report inc...

R. C. Galijan

1996-01-01

406

Chemical and Solar Electric Propulsion Systems Analyses for Mars Sample Return Missions  

NASA Technical Reports Server (NTRS)

Conceptual in-space transfer stages, including those utilizing solar electric propulsion, chemical propulsion, and chemical propulsion with aerobraking or aerocapture assist at Mars, were evaluated. Roundtrip Mars sample return mission vehicles were analyzed to determine how specific system technology selections influence payload delivery capability. Results show how specific engine, thruster, propellant, capture mode, trip time and launch vehicle technology choices would contribute to increasing payload or decreasing the size of the required launch vehicles. Heliocentric low-thrust trajectory analyses for Solar Electric Transfer were generated with the SEPTOP code.

Donahue, Benjamin B.; Green, Shaun E.; Coverstone, Victoria L.; Woo, Byoungsam

2004-01-01

407

Comparative analyses of amplicon migration behavior in differing denaturing gradient gel electrophoresis (DGGE) systems  

NASA Astrophysics Data System (ADS)

Denaturing gradient gel electrophoresis (DGGE) is commonly utilized to identify and quantify microbial diversity, but the conditions required for different electrophoretic systems to yield equivalent results and optimal resolution have not been assessed. Herein, the influence of different DGGE system configuration parameters on microbial diversity estimates was tested using Symbiodinium, a group of marine eukaryotic microbes that are important constituents of coral reef ecosystems. To accomplish this, bacterial clone libraries were constructed and sequenced from cultured isolates of Symbiodinium for the ribosomal DNA internal transcribed spacer 2 (ITS2) region. From these, 15 clones were subjected to PCR with a GC clamped primer set for DGGE analyses. Migration behaviors of the resulting amplicons were analyzed using a range of conditions, including variation in the composition of the denaturing gradient, electrophoresis time, and applied voltage. All tests were conducted in parallel on two commercial DGGE systems, a C.B.S. Scientific DGGE-2001, and the Bio-Rad DCode system. In this context, identical nucleotide fragments exhibited differing migration behaviors depending on the model of apparatus utilized, with fragments denaturing at a lower gradient concentration and applied voltage on the Bio-Rad DCode system than on the C.B.S. Scientific DGGE-2001 system. Although equivalent PCR-DGGE profiles could be achieved with both brands of DGGE system, the composition of the denaturing gradient and application of electrophoresis time × voltage must be appropriately optimized to achieve congruent results across platforms.

Thornhill, D. J.; Kemp, D. W.; Sampayo, E. M.; Schmidt, G. W.

2010-03-01

408

Assessment of Tools and Data for System-Level Dynamic Analyses  

SciTech Connect

The only fuel cycle for which dynamic analyses and assessments are not needed is the null fuel cycle - no nuclear power. For every other concept, dynamic analyses are needed and can influence relative desirability of options. Dynamic analyses show how a fuel cycle might work during transitions from today's partial fuel cycle to something more complete, impact of technology deployments, location of choke points, the key time lags, when benefits can manifest, and how well parts of fuel cycles work together. This report summarizes the readiness of existing Fuel Cycle Technology (FCT) tools and data for conducting dynamic analyses on the range of options. VISION is the primary dynamic analysis tool. Not only does it model mass flows, as do other dynamic system analysis models, but it allows users to explore various potential constraints. The only fuel cycle for which constraints are not important are those in concept advocates PowerPoint presentations; in contrast, comparative analyses of fuel cycles must address what constraints exist and how they could impact performance. The most immediate tool need is extending VISION to the thorium/U233 fuel cycle. Depending on further clarification of waste management strategies in general and for specific fuel cycle candidates, waste management sub-models in VISION may need enhancement, e.g., more on 'co-flows' of non-fuel materials, constraints in waste streams, or automatic classification of waste streams on the basis of user-specified rules. VISION originally had an economic sub-model. The economic calculations were deemed unnecessary in later versions so it was retired. Eventually, the program will need to restore and improve the economics sub-model of VISION to at least the cash flow stage and possibly to incorporating cost constraints and feedbacks. There are multiple sources of data that dynamic analyses can draw on. In this report, 'data' means experimental data, data from more detailed theoretical or empirical calculations on technology performance, and assumptions such as the earliest date a technology can be deployed. The only fuel cycles for which we currently have adequate data are those we are sure we will never build, e.g., a PUREX plant in the U.S. For actual candidates, even for once through LWRs, there remain missing data such as how the fuel cycle would be completed with a geologic repository. The most immediate data needs are probably basic reactor physics data for new concepts and data associated with waste management for anything other than current technology. The readiness of tools and data is fluid and depends on what purposes are envisioned to drive upcoming analyses and further definition of the waste-related characteristics of fuel cycle candidates. Tools and data sets evolve as needs evolve. Thus, much of the document explains that if the FCT program wants a certain type of analysis, then the tools and data needs are as indicated. For example, functions can be treated as either commodities or facilities. Reactors, separation, fuel fabrication, repository are treated as facility types. Other functions such as uranium mining, conversion, enrichment, and waste packaging and non-repository disposal are treated as commodities and therefore not modeled as extensively. In summary, the tools are functional and can answer many fuel cycle questions but some analyses will require that the tools be modified to support those analyses.

Steven J. Piet; Nick R. Soelberg

2011-06-01

409

ITER cryopump handling study preliminary report.  

National Technical Information Service (NTIS)

The scope of this study was to develop a remote handling concept for the primary vacuum pumping system by performing the following tasks: review the cryopump duct configuration and remote handling requirements for cryopump replacement; initiate an ITER Cr...

T. Haines

1996-01-01

410

Progress in Intergration of Iter Microwave Diagnostics  

NASA Astrophysics Data System (ADS)

This paper reports on the current status of integration of ITER microwave diagnostics, such as ECE, reflectometry systems and Collective Thomson scattering, and gives an outlook on the upcoming technical and design activity. Some open issues are addressed and discussed.

Udintsev, V. S.; Vayakis, G.; Cantone, B.; Encheva, A.; Walker, C.; Benchikhoune, M.; Costley, A. E.; Dammann, A.; Henderson, M. A.; Kuehn, I.; Lee, C. H.; Levesy, B.; Martin, A.; Patel, K. M.; Pitcher, C. S.; Tesini, A.; Utin, Y.; Walsh, M. J.; Danani, S.; Pandya, H.; Vasu, P.; Austin, M.; Rowan, W.; Feder, R.; Johnson, D.; Shelukhin, D.; Vershkov, V.; Counsell, G.; Ingesson, Ch.; Arshad, S.

2011-02-01

411

Study of the ITER ICRH system with external matching by means of a mock-up loaded by a variable water load  

SciTech Connect

A mock-up of the complete antenna array (24 straps grouped in 8 triplets) of the ICRH system with external matching for ITER has been constructed with a length reduction factor of 5. At a frequency increased by the same factor the electrical properties of the full-scale system can be measured. A movable water tank in front of the array simulates variable plasma loading. Measurements of the matching performances of various external circuit configurations and of the scattering matrix of the system show (i) the non-negligible effect of mutual coupling on load resilient matching by Conjugate-T (CT) or hybrid leading to coupling between the matching actuators and the generators and asymmetry in power distribution, (ii) good load resilience of a single CT for the right choice of configuration and number of matching parameters, (iii) the large number of matching solutions for coupled CT's, (iv) the benefit of passive power distribution to the straps.

Messiaen, A.; Vervier, M.; Dumortier, P.; Lamalle, P.; Louche, F. [LPP-ERM/KMS, EURATOM-Belgian State Association, Trilateral Euregio Cluster, B-1000 Brussels (Belgium)

2005-09-26

412

ITER council proceedings: 1993.  

National Technical Information Service (NTIS)

Records of the third ITER Council Meeting (IC-3), held on 21-22 April 1993, in Tokyo, Japan, and the fourth ITER Council Meeting (IC-4) held on 29 September - 1 October 1993 in San Diego, USA, are presented, giving essential information on the evolution o...

1994-01-01

413

Iteration, Not Induction  

ERIC Educational Resources Information Center

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…

Dobbs, David E.

2009-01-01

414

The Predicted Arabidopsis Interactome Resource and Network Topology-Based Systems Biology Analyses[W][OA  

PubMed Central

Predicted interactions are a valuable complement to experimentally reported interactions in molecular mechanism studies, particularly for higher organisms, for which reported experimental interactions represent only a small fraction of their total interactomes. With careful engineering consideration of the lessons from previous efforts, the Predicted Arabidopsis Interactome Resource (PAIR; ) presents 149,900 potential molecular interactions, which are expected to cover ~24% of the entire interactome with ~40% precision. This study demonstrates that, although PAIR still has limited coverage, it is rich enough to capture many significant functional linkages within and between higher-order biological systems, such as pathways and biological processes. These inferred interactions can nicely power several network topology-based systems biology analyses, such as gene set linkage analysis, protein function prediction, and identification of regulatory genes demonstrating insignificant expression changes. The drastically expanded molecular network in PAIR has considerably improved the capability of these analyses to integrate existing knowledge and suggest novel insights into the function and coordination of genes and gene networks.

Lin, Mingzhi; Zhou, Xi; Shen, Xueling; Mao, Chuanzao; Chen, Xin

2011-01-01

415

ITER divertor, design issues and research and development  

Microsoft Academic Search

Over the period of the ITER Engineering Design Activity (EDA) the results from physics experiments, modelling, engineering analyses and R&D, have been brought together to provide a design for an ITER divertor. The design satisfies all necessary requirements for steady state and transient heat flux, nuclear shielding, pumping, tritium inventory, impurity control, armour lifetime, electromagnetic loads, diagnostics, and remote maintenance.

R. Tivey; T. Ando; A. Antipenkov; V. Barabash; S. Chiocchio; G. Federici; C. Ibbott; R. Jakeman; G. Janeschitz; R. Raffray; M. Akiba; I. Mazul; H. Pacher; M. Ulrickson; G. Vieider

1999-01-01

416

US ITER background summary papers.  

National Technical Information Service (NTIS)

The following brief summaries were prepared by members of the US ITER Home Team to provide background information on the ITER CDA design and in several instances to provide personal observations and suggestions regarding continuation of the ITER Conceptua...

J. N. Doggett C. A. Flanagan D. E. Post J. C. Wesley

1991-01-01

417

Reliability-aware iterative detection scheme (RAID) for distributed IDM space-time codes in relay systems  

NASA Astrophysics Data System (ADS)

In this article, distributed interleave-division multiplexing space-time codes (dIDM-STCs) are applied for multi-user two-hop decode-and-forward (DF) relay networks. In case of decoding errors at the relays which propagate to the destination, severe performance degradations can occur as the original detection scheme for common IDM-STCs does not take any reliability information about the first hop into account. Here, a novel reliability-aware iterative detection scheme (RAID) for dIDM-STCs is proposed. This new detection scheme takes the decoding reliability of the relays for each user into account for the detection at the destination. Performance evaluations show that the proposed RAID scheme clearly outperforms the original detection scheme and that in certain scenarios even a better performance than for adaptive relaying schemes can be achieved.

Lenkeit, Florian; Wübben, Dirk; Dekorsy, Armin

2013-12-01

418

Scenario evolution: Interaction between event tree construction and numerical analyses  

SciTech Connect

Construction of well-posed scenarios for the range of conditions possible at any proposed repository site is a critical first step to assessing total system performance. Event tree construction is the method that is being used to develop potential failure scenarios for the proposed nuclear waste repository at Yucca Mountain. An event tree begins with an initial event or condition. Subsequent events are listed in a sequence, leading eventually to release of radionuclides to the accessible environment. Ensuring the validity of the scenarios requires iteration between problems constructed using scenarios contained in the event tree sequence, experimental results, and numerical analyses. Details not adequately captured within the tree initially may become more apparent as a result of analyses. To illustrate this process, the authors discuss the iterations used to develop numerical analyses for PACE-90 (Performance Assessment Calculational Exercises) using basaltic igneous activity and human-intrusion event trees.

Barr, G.E.; Barnard, R.W.; Dockery, H.A.; Dunn, E. [Sandia National Labs., Albuquerque, NM (USA); MacIntyre, A.T. [Lawrence Livermore National Lab., CA (USA)

1990-12-31

419

Results of the implementation on a mock-up of the full 3dB hybrid matching option of the ITER ICRH system  

SciTech Connect

Each of the two ICRH antennas for ITER must couple 20MW to the plasma in the 40-55MHz band via an array of 24 radiating shorted straps fed by four generators. The matching system must provide automatic matching control on the mean load provided by the plasma and be resilient (parallel {Gamma}{sub G} parallel <0.2) to a wide range of fast antenna load excursions occurring in ELMy plasmas. Furthermore, good control of the current distribution in the strap array must be possible for the various heating and current drive scenarios. Two load resilient matching options have been considered for ITER: the 4 'Conjugate-T'(CT) and the 4 hybrids ones, the first being presently considered as a back-up option. Automatic control of these 2 options has been developed, and tested for optimization on a low-powered scaled mock-up. Successful implementation of the simultaneous feedback control of 11 actuators for the matching of the 4 CT and for the control of the toroidal phasing has already been achieved. The matching and the array current control of the 3dB hybrid option are provided by simultaneous feedback control of the decouplers and double stub tuners (in total 23 actuators) and this has also been successfully achieved for the full array. The paper discusses the circuit implementation and presents the obtained results.

Grine, D.; Vervier, M.; Messiaen, A.; Dumortier, P. [LPP-ERM/KMS, EURATOM-Belgian State Association, TEC, Brussels (Belgium)

2011-12-23

420

Results of the implementation on a mock-up of the full 3dB hybrid matching option of the ITER ICRH system  

NASA Astrophysics Data System (ADS)

Each of the two ICRH antennas for ITER must couple 20MW to the plasma in the 40-55MHz band via an array of 24 radiating shorted straps fed by four generators. The matching system must provide automatic matching control on the mean load provided by the plasma and be resilient (||?G||<0.2) to a wide range of fast antenna load excursions occurring in ELMy plasmas. Furthermore, good control of the current distribution in the strap array must be possible for the various heating and current drive scenarios. Two load resilient matching options have been considered for ITER: the 4 `Conjugate-T' (CT) and the 4 hybrids ones, the first being presently considered as a back-up option [1]. Automatic control of these 2 options has been developed, and tested for optimization on a low-powered scaled mock-up. Successful implementation of the simultaneous feedback control of 11 actuators for the matching of the 4 CT and for the control of the toroidal phasing has already been achieved [2]. The matching and the array current control of the 3dB hybrid option are provided by simultaneous feedback control of the decouplers and double stub tuners (in total 23 actuators) and this has also been successfully achieved for the full array. The paper discusses the circuit implementation and presents the obtained results.

Grine, D.; Vervier, M.; Messiaen, A.; Dumortier, P.

2011-12-01

421

Quench of ITER Poloidal Field Coils: Influence of some initiation parameters on thermo-hydraulic detection signals and main impact on cryogenic system  

NASA Astrophysics Data System (ADS)

In case of a magnet quench, the primary quench detection system is classically based on voltage detection. In addition, a secondary quench detection is required and it could rely on signals of thermohydraulic nature. A model based on the coupled GANDALF [1] and FLOWER [2] codes has been developed in previous papers for the Central Solenoid [3,4], and for the Toroidal Field Coils [5,6] of ITER. This study focuses on Poloidal Field Coil PF5 as it has the highest magnetic field value along the conductor. Results of some parametric studies are presented and the influence of the initiation parameters of the quench (energy, location and length of heat deposition, time duration for detection). The possibility of a secondary thermohydraulic detection and the main impact on cryogenic system are analyzed and discussed.

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

2013-01-01

422

Peptidomic and proteomic analyses of the systemic immune response of Drosophila.  

PubMed

Insects have developed an efficient host defense against microorganisms, which involves humoral and cellular mechanisms. Numerous data highlight similarities between defense responses of insects and innate immunity of mammals. The fruit fly, Drosophila melanogaster, is a favorable model system for the analysis of the first line defense against microorganisms. Taking advantages of improvements in mass spectrometry (MS), two-dimensional (2D) gel electrophoresis and bioinformatics, differential analyses of blood content (hemolymph) from immune-challenged versus control Drosophila were performed. Two strategies were developed: (i) peptidomic analyses through matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS and high performance liquid chromatography for molecules below 15 kDa, and (ii) proteomic studies based on 2D gel electrophoresis, MALDI-TOF fingerprinting and database searches, for compounds of greater molecular masses. The peptidomic strategy led to the detection of a large number of peptides induced in the hemolymph of challenged flies as compared to controls. Of these, 28 were characterized, amongst which were antimicrobial peptides. The 2D gel electrophoresis strategy led to the detection of 70 spots differentially regulated by at least fivefold after microbial infection. This approach yielded the identity of a series of proteins that were related to the Drosophila immune response, such as proteases, protease inhibitors, prophenoloxydase-activating enzymes, serpins and a Gram-negative binding protein-like protein. This strategy also brought to light new candidates with a potential function in the immune response (odorant-binding protein, peptidylglycine alpha-hydroxylating monooxygenase and transferrin). Interestingly, several molecules resulting from the cleavage of proteins were detected after a fungal infection. Together, peptidomic and proteomic analyses represent new tools to characterize molecules involved in the innate immune reactions of Drosophila. PMID:15556270

Levy, Francine; Rabel, David; Charlet, Maurice; Bulet, Philippe; Hoffmann, Jules A; Ehret-Sabatier, Laurence

2004-01-01

423

A distributed computing system for multivariate time series analyses of multichannel neurophysiological data.  

PubMed

We present a client-server application for the distributed multivariate analysis of time series using standard PCs. We here concentrate on analyses of multichannel EEG/MEG data, but our method can easily be adapted to other time series. Due to the rapid development of new analysis techniques, the focus in the design of our application was not only on computational performance, but also on high flexibility and expandability of both the client and the server programs. For this purpose, the communication between the server and the clients as well as the building of the computational tasks has been realized via the Extensible Markup Language (XML). Running our newly developed method in an asynchronous distributed environment with random availability of remote and heterogeneous resources, we tested the system's performance for a number of different univariate and bivariate analysis techniques. Results indicate that for most of the currently available analysis techniques, calculations can be performed in real time, which, in principle, allows on-line analyses at relatively low cost. PMID:16253340

Müller, Andy; Osterhage, Hannes; Sowa, Robert; Andrzejak, Ralph G; Mormann, Florian; Lehnertz, Klaus

2006-04-15

424

Iterative QR detection for BLAST  

Microsoft Academic Search

Abstract. We study an iterative detection algorithm of an uncoded multi-transmitter multi-receiver system. The main data stream is demultiplexed into M substreams, and each substream is modulated,independently then transmitted by its dedicated antenna. The receiver disposes of N ? M antennas. Over each receive antenna the signal is a superposition of the M substreams affected by independent fades and disturbed

M. O. Damen; K. Abed-meraim; S. Burykh

2001-01-01

425

ACCIDENT ANALYSES & CONTROL OPTIONS IN SUPPORT OF THE SLUDGE WATER SYSTEM SAFETY ANALYSIS  

SciTech Connect

This report documents the accident analyses and nuclear safety control options for use in Revision 7 of HNF-SD-WM-SAR-062, ''K Basins Safety Analysis Report'' and Revision 4 of HNF-SD-SNF-TSR-001, ''Technical Safety Requirements - 100 KE and 100 KW Fuel Storage Basins''. These documents will define the authorization basis for Sludge Water System (SWS) operations. This report follows the guidance of DOE-STD-3009-94, ''Preparation Guide for US. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports'', for calculating onsite and offsite consequences. The accident analysis summary is shown in Table ES-1 below. While this document describes and discusses potential control options to either mitigate or prevent the accidents discussed herein, it should be made clear that the final control selection for any accident is determined and presented in HNF-SD-WM-SAR-062.

WILLIAMS, J.C.

2003-11-15

426

Error analyses and calibration methods with accelerometers for optical angle encoders in rotational inertial navigation systems.  

PubMed

By rotating a strapdown inertial navigation system (INS) over one or more axes, a number of error sources originating from the employed sensors cancel out during the integration process. Rotary angle accuracy has an effect on the performance of rotational INS (RINS). The application of existing calibration methods based on gyroscope measurements is restricted by the structure of the inertial measurement unit (IMU) and scale factor stability of the gyroscope. The multireadhead method has problems in miniaturization and cost. Hence, optical angle encoder calibration methods using accelerometers are proposed, on the basis of navigation error and accuracy requirement analyses for a single-axis RINS. The test results show that the accuracy of calibration methods proposed is higher than 4 arcsec (1?). PMID:24216731

Liu, Fang; Wang, Wei; Wang, Lei; Feng, Peide

2013-11-10

427

Distinct Signaling Roles of Ceramide Species in Yeast Revealed Through Systematic Perturbation and Systems Biology Analyses  

PubMed Central

Ceramide, the central molecule of sphingolipid metabolism, is an important bioactive molecule participating in cellular regulatory events and having implications for disease. A challenge in deciphering ceramide signaling emanates from the myriad of ceramide species that exist and the possibility that many of them may have distinct functions. Here, we applied systems biology and molecular approaches to perturb ceramide metabolism in the yeast (Saccharomyces cerevisiae) and inferred causal relationships between ceramide species and their potential targets by combining lipidomic, genomic, and transcriptomic analyses. We find that during heat stress distinct metabolic mechanisms control the abundance of different groups of ceramide species. Additionally, distinct groups of ceramide species regulated different sets of functionally related genes, indicating that specific sub-groups of lipids participated in different regulatory pathways. These results indicate a previously unrecognized complexity and versatility of lipid-mediated cell regulation.

Montefusco, David J.; Chen, Lujia; Matmati, Nabil; Lu, Songjian; Newcomb, Benjamin; Cooper, Gregory F.; Hannun, Yusuf A.; Lu, Xinghua

2014-01-01

428

Performance Analyses of 38 kWe Turbo-Machine Unit for Space Reactor Power Systems  

NASA Astrophysics Data System (ADS)

This paper developed a design and investigated the performance of 38 kWe turbo-machine unit for space nuclear reactor power systems with Closed Brayton Cycle (CBC) energy conversion. The compressor and turbine of this unit are scaled versions of the NASA's BRU developed in the sixties and seventies. The performance results of turbo-machine unit are calculated for rotational speed up to 45 krpm, variable reactor thermal power and system pressure, and fixed turbine and compressor inlet temperatures of 1144 K and 400 K. The analyses used a detailed turbo-machine model developed at the University of New Mexico that accounts for the various energy losses in the compressor and turbine and the effect of compressibility of the He-Xe (40 mole/g) working fluid with increased flow rate. The model also accounts for the changes in the physical and transport properties of the working fluid with temperature and pressure. Results show that a unit efficiency of 24.5% is achievable at rotation speed of 45 krpm and system pressure of 0.75 MPa, assuming shaft and electrical generator efficiencies of 86.7% and 90%. The corresponding net electric power output of the unit is 38.5 kWe, the flow rate of the working fluid is 1.667 kg/s, the pressure ratio and polytropic efficiency for the compressor are 1.60 and 83.1%, and 1.51 and 88.3% for the turbine.

Gallo, Bruno M.; El-Genk, Mohamed S.

2008-01-01

429

Single-particle and many-body analyses of a quasiperiodic integrable system after a quench  

NASA Astrophysics Data System (ADS)

In general, isolated integrable quantum systems have been found to relax to an apparent equilibrium state in which the expectation values of few-body observables are described by the generalized Gibbs ensemble. However, recent work has shown that relaxation to such a generalized statistical ensemble can be precluded by localization in a quasiperiodic lattice system. Here we undertake complementary single-particle and many-body analyses of noninteracting spinless fermions and hard-core bosons within the Aubry-André model to gain insight into this phenomenon. Our investigations span both the localized and delocalized regimes of the quasiperiodic system, as well as the critical point separating the two. Considering first the case of spinless fermions, we study the dynamics of the momentum distribution function and characterize the effects of real-space and momentum-space localization on the relevant single-particle wave functions and correlation functions. We show that although some observables do not relax in the delocalized and localized regimes, the observables that do relax in these regimes do so in a manner consistent with a recently proposed Gaussian equilibration scenario, whereas relaxation at the critical point has a more exotic character. We also construct various statistical ensembles from the many-body eigenstates of the fermionic and bosonic Hamiltonians and study the effect of localization on their properties.

He, Kai; Santos, Lea F.; Wright, Tod M.; Rigol, Marcos

2013-06-01

430

Neutral particle beam alternative concept for ITER  

Microsoft Academic Search

An analysis of an ITER neutral particle beam system is presented. The analysis covers the neutralizer, ion dumps, pumping, and geometric aspects. The US beam concept for ITER consists of three or four clusters of beamlines delivering approximately 80 MW total of 1.6-MeV deuterium to three or four reactor ports. Each cluster has three self-contained beamlines featuring plasma neutralizers and

D. Sedgley; J. Brook; T. Luzzi; L. Deutsch

1989-01-01

431

A new class of split exponential propagation iterative methods of Runge-Kutta type (sEPIRK) for semilinear systems of ODEs  

NASA Astrophysics Data System (ADS)

In this paper the framework of the exponential propagation iterative methods of Runge-Kutta type (EPIRK) is extended to construct split EPIRK (sEPIRK) integrators for semilinear systems of ODEs. The structure of the sEPIRK methods possesses the flexibility and generality that allows construction of very efficient schemes. We demonstrate how bicolored trees-based B-series can be used to derive the order conditions for the new integrators. An algorithm is developed to solve the order conditions up to order three and several new schemes with desirable properties are proposed. The numerical results illustrate the advantages offered by the new class of integrators. The experiments also address the comparative performance of split vs. non-split EPIRK methods and the question of improving efficiency by optimizing coefficients of the sEPIRK schemes. It is shown that specific schemes can be custom-built to improve computational efficiency for a particular problem.

Rainwater, G.; Tokman, M.

2014-07-01

432

Diagnostics for ITER  

SciTech Connect

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

Donne, A. J. H.; Hellermann, M. G. von [FOM-Institute for Plasma Physics Rijnhuizen, Association Euratom-FOM, Partner in ITER-NL, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Barnsley, R. [ITER International Organization, Cadarache Centre, 13108 St Paul-Les-Durance (France)

2008-10-22

433

Predicting US summer precipitation using NCEP Climate Forecast System version 2 initialized by multiple ocean analyses  

NASA Astrophysics Data System (ADS)

This study examines the prediction skill of the contiguous United States (CONUS) precipitation in summer, as well as its potential sources using a set of ensemble hindcasts conducted with the National Centers for Environmental Prediction (NCEP) Climate Forecast System version 2 and initialized from four independent ocean analyses. The multiple ocean ensemble mean (MOCN_ESMEAN) hindcasts start from each April for 26 summers (1982-2007), with each oceanic state paired with four atmosphere-land states. A subset of hindcasts from the NCEP CFS Reanalysis and Reforecast (CFSRR) project for the same period, from the same initial month and with the same total ensemble size, is also analyzed. Compared with CFSRR, MOCN_ESMEAN is distinguished by its oceanic ensemble spread that introduces potentially larger perturbations and better spatial representation of the oceanic uncertainty. The prediction skill of the CONUS precipitation in summer shows a similar spatial pattern in both MOCN_ESMEAN and CFSRR, but the results suggested that initialization from multiple ocean analyses may bring more robust signals and additional skills to the seasonal prediction for both sea surface temperature and precipitation. Among the predictable areas for precipitation, the northwestern CONUS (NWUS) is the most robust. A further analysis shows that the enhanced summer precipitation prediction skill in NWUS is mainly associated with the El Niño/Southern Oscillation, with possible influence also from the Pacific Decadal Oscillation. Through this work, we argue that a large ensemble is necessary for precipitation forecast in mid-latitudes, such as the CONUS, and taking into account of the oceanic initial state uncertainty is an efficient way to build such an ensemble.

Zhu, Jieshun; Huang, Bohua; Hu, Zeng-Zhen; Kinter, James L.; Marx, Lawrence

2013-10-01

434

Design, stability and robustness analyses of neural networks in control systems  

NASA Astrophysics Data System (ADS)

Artificial Neural Network (ANN), also known as connectionist learning and parallel distributed processing, is finding its applications in diverse fields: many branches of engineering, health sciences, cognitive science, archaeology, finance, etc. This research tries to make some efforts to emphasize "design" methodology in ANN, and to explore the structures by which ANN can solve difficult problems by identifying proper ANN architecture. Two classes of ANN--multi-layer neural networks and recurrent networks--are investigated in the context of control of systems and estimation of unknown parameters. The multi-layer neural networks converge to optimal solutions by satisfying mathematical formulations associated with the Hamilton approach and the dynamic programming approach. A benchmark aerospace application is used for illustration. A variant of the Hopfield network, called the Modified Hopfield Neural Network (MHNN), is proposed to show the design approach to the determination of weights in recurrent networks. It is shown how the equilibrium point of this network helps with inversion operations arising in optimal gain determination. Control of dynamic systems using recurrent neural networks are presented. The robustness of the recurrent networks to parameter variation is considered in the context of weights. Analyses are carried out in the frequency domain and the time domain.

Shen, Jie

435

InnateDB: facilitating systems-level analyses of the mammalian innate immune response  

PubMed Central

Although considerable progress has been made in dissecting the signaling pathways involved in the innate immune response, it is now apparent that this response can no longer be productively thought of in terms of simple linear pathways. InnateDB (www.innatedb.ca) has been developed to facilitate systems-level analyses that will provide better insight into the complex networks of pathways and interactions that govern the innate immune response. InnateDB is a publicly available, manually curated, integrative biology database of the human and mouse molecules, experimentally verified interactions and pathways involved in innate immunity, along with centralized annotation on the broader human and mouse interactomes. To date, more than 3500 innate immunity-relevant interactions have been contextually annotated through the review o