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Now showing items 1 - 16 of 149

  • The JET upgraded toroidal Alfvén Eigenmode Diagnostic System

    Dowson, S.   Dorling, S.   Sheikh, H.K.   Blackman, T.   Jones, G.   Goodyear, A.   Puglia, P.   Blanchard, P.   Fasoli, A.   Testa, D.   Fil, N.   Aslanyan, V.   Porkolab, M.   Woskov, P.   De Sa, W. Pires   Galvao, R.   Ruchko, L.   Figueiredo, J.   Von Thun, C. Perez  

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  • Real-time control of multiple MHD instabilities on TCV by ECRH/ECCD

    Felici, F.   Rossel, J.X.   Canal, G.   Coda, S.   Duval, B.P.   Goodman, T.P.   Martin, Y.   Moret, J-M.   Sauter, O.   Testa, D.  

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  • Triggering a large scale luminescent solar concentrators market: The smart window project

    Aste, N.   Buzzetti, M.   Del Pero, C.   Fusco, R.   Leonforte, F.   Testa, D.  

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  • The JET Alfvén Eigenmode Local Manager for the real-time detection and tracking of MHD instabilities

    Testa, D.   Carfantan, H.   Goodyear, A.   Blanchard, P.   Klein, A.   Panis, T.   contributors, JET-EFDA  

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  • Evidence for a new path to the self-sustainment of thermonuclear fusion in magnetically confined plasmas

    Testa, D.   Albergante, M.  

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  • The Magnetic Diagnostic Set for ITER

    Testa, D.   Toussaint, M.   Chavan, R.   Guterl, J.   Lister, J.B.   Moret, J.-M.   Perez, A.   Sanchez, F.   Schaller, B.   Tonetti, G.   Encheva, A.   Vayakis, G.   Walker, C.   Fournier, Y.   Maeder, T.   Le-Luyer, A.   Moreau, P.   Chitarin, G.   Alessi, E.   Delogu, R.S.   Gallo, A.   Marconato, N.   Peruzzo, S.   Preindl, M.   Carfantan, H.   Hodgson, E.   Romero, J.   Vila, R.   Brichard, B.   Vermeeren, L.  

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  • Chronic treatment with l-threonine in amyotrophic lateral sclerosis: a pilot study

    Testa, D.   Caraceni, T.   Fetoni, V.   Girotti, F.  

    Thirty patients suffering from amyotrophic lateral sclerosis were included in an open therapeutical trial. They were randomized to receive either L-threonine (Thr), a precursor of the inhibitory amino acid glycine, or vitamin B or carnitine. Thirteen patients (9 patients on Thr and 4 control subjects) completed the 1-year trial. No statistical differences were observed between the treated group and the control patients in the decline of the clinical assessment score. Nevertheless, Thr-treated patients complained less frequently of respiratory failure than the control group despite bulbar involvement being more common in the Thr group at entry.
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  • Measurements of the radial profile of the plasma isotopic composition in JET plasmas using Alfvén eigenmodes

    Testa, D.   Blanchard, P.   Panis, T.  

    The measurement of the plasma isotopic composition is necessary in future burning plasma devices such as ITER and DEMO as a tool for optimizing the deuterium/tritium (DT) fusion performance. This paper reports on the results of experiments performed on the JET tokamak where toroidal Alfvén eigenmodes (TAEs) with toroidal mode number (N) up to were actively driven with a set of in-vessel antennas, and were then used to infer the value of the plasma isotopic composition at different radial positions. A novel and important result with respect to previous work on JET is that by correctly including the effect of plasma impurities in the calculation of the Alfvén frequency, through its dependence on the plasma mass, it has become now possible to distinguish plasmas with different majority ion species but with the same charge-to-mass ratio, notably majority deuterium and helium4 plasmas. Furthermore, and combined with modelling of AEs in JET discharges, these experimental results indicate that a diagnostic system based on the detection of AEs with different toroidal mode numbers and at different frequencies, could provide profile measurements of the plasma isotopic composition in future burning plasma devices such as ITER and DEMO.
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  • A phenomenological explanation for the anomalous ion heating observed in the JET alpha-heating experiment of 1997

    Testa, D.   Albergante, M.  

    In the so-called `alpha-heating' experiment performed on the JET tokamak during the deuterium-tritium campaign of 1997, the ion temperature was found to be far exceeding (both in absolute value and in its rise time) the level that could have been expected from direct collisional heating by the fusion-born alpha particles themselves and energy equipartition with the electrons. To date, no explanation has been put forward for this long standing puzzle, despite much work having been performed on this subject in the early 2000s. Two analysis methods that have recently become available have been employed to re-analyse these observations of an anomalous ion heating. First, an algorithm based on the sparse representation of signals has been used to analyse magnetic, reflectometry and electron-cyclotron emission measurements of the turbulence spectra in the drift-wave range of frequencies. This analysis has then been complemented with turbulence simulations performed with the GENE code. We find, both experimentally and in the simulations, that the presence of a minority, but sufficiently large, population of fusion-born alpha particles that have not yet fully thermalized stabilizes the turbulence in the ion-drift direction, but practically does not affect the turbulence in the electron-drift direction. We link such stabilization of the ion-drift-wave turbulence to the increase in the ion temperature above the level achieved in similar discharges that did not have (at all or enough) alpha particles. When the fusion-born alpha particles have fully thermalized, the turbulence spectrum in the ion-drift direction reappears at somewhat larger amplitudes, which we link to the ensuing reduction in the ion temperature. This phenomenological dynamics fully corresponds to the actual experimental observations. By taking into account an effect of the alpha particles that had not been previously considered, our new analysis finally presents a phenomenological explanation for the so-far-unexplained anomalous ion heating observed in the JET alpha-heating experiment of 1997. Through the formulation of an empirical criterion for ion-drift-wave turbulence stabilization by fusion-born alpha particles, we also show why similar observations were not made in the other deuterium-tritium experiments run so far in JET and TFTR. This allows assessing the operational domain for this stabilization mechanism for ion-drift-wave turbulence in future burning plasma experiments such as ITER, which may open a new path towards the sustainment of a high energy gain in such forthcoming devices.
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  • Plasma isotopic effect on the damping rate of toroidal Alfvén eigenmodes with intermediate toroidal mode numbers

    Testa, D.   Panis, T.   Blanchard, P.   Fasoli, A.  

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  • Functional Performance Analysis and Optimization for the High-Frequency Magnetic Diagnostic System in ITER — I: Overview of the Results

    Testa, D.   Carfantan, H.   Chavan, R.   Lister, J. B.   Moret, J-M.   Toussaint, M.  

    The measurement performance of the baseline system design for the ITER high-frequency magnetic diagnostic has been analyzed using an algorithm based on the sparse representation of signals. This algorithm, derived from the SparSpec code [S. Bourguignon et al., Astron. Astrophys., 462, 379 (2007)] has previously been extensively bench marked on real and simulated JET data. To optimize the system design of the ITER high-frequency magnetic diagnostic, we attempt to reduce false detection of the modes and to minimize the sensitivity of the measurement with respect to noise in the data, loss of faulty sensors, and the displacement of the sensors. Using this approach, the original layout design for the ITER high-frequency magnetic diagnostic system, which uses 168 sensors, is found to be inadequate to meet the ITER measurement requirements. Based on this analysis, and taking into account the guidelines for the risk mitigation strategies that are given in the ITER management plan, various attempts at optimization of this diagnostic system have been performed. A revised proposal for its implementation has been developed, which now meets the ITER requirements for measurement performance and risk management. For toroidal mode number detection, this implementation includes two arrays of 50 to 55 sensors and two arrays of 25 to 35 unevenly spaced sensors each on the low-field side and two arrays of 25 to 35 unevenly spaced sensors each on the high-field side. For poloidal mode number detection, we propose six arrays of 25 to 40 sensors each located in nonequidistant machine sectors, not covering the divertor region and, possibly, poloidal angles in the range 75 < vertical bar theta vertical bar(deg) < 105, as this region is the most sensitive to the details of the magnetic equilibrium. In this paper we present the general summary results of this work, for which more details and an overview of our test calculations are reported in the companion paper.
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  • In vitro synthesis of the full-length complement of the negative-strand genome RNA of vesicular stomatitis virus.

    Testa, D.   Chanda, P. K.   Banerjee, A. K.  

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  • R. H. Kosobud, W. A. Testa, D. A. Hanson (eds.),cost effective control of urban smog, Federal Reserve Bank of Chicago, 1993, 214 pp.

    Mark Jacobson  

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  • Prototyping a High-Frequency Inductive Magnetic Sensor Using the Nonconventional, Low-Temperature Co-Fired Ceramic Technology for Use in ITER

    Testa, D.   Fournier, Y.   Maeder, T.   Toussaint, M.   Chavan, R.   Guterl, J.   Lister, J. B.   Moret, J-M.   Schaller, B.   Tonetti, G.  

    The ITER high-frequency (HF) magnetic sensor is currently intended to be a conventional, Mirnov-type, pickup coil, designed to provide measurements of magnetic instabilities with magnitude as low as vertical bar delta B vertical bar similar to 10(-4) G at the position of the sensors and up to frequencies of at least 300 kHz. Previous prototyping of this sensor has indicated that a number of problems exist with this conventional design that are essentially related to the winding process and the differential thermal expansion between the metallic wire and the ceramic spacers. Hence, a nonconventional HF magnetic sensor has been designed and prototyped in-house in different variants using low-temperature co-fired ceramic (LTCC) technology, which involves a series of stacked ceramic substrates with a circuit board printed on them with a metallic ink (silver in our case). A method has then been developed to characterize the electrical properties of these sensors from the direct-current range up to frequencies in excess of 10 MHz. This method has been successfully bench-marked against the measurements for the built sensors and allows the electrical properties of LTCC prototypes to be predicted with confidence and without the need of actually building them, which therefore significantly simplifies future research and development (R&D) activities. When appropriate design choices are made, LTCC sensors are found to meet in full the volume occupation constraints and the requirements for the sensor's electrical properties that are set out for the ITER HF magnetic diagnostic system. This nonconventional technology is therefore recommended for further R&D and prototyping work, particularly for a three-dimensional sensor, and possibly using materials more suitable for use in the ITER environment, such as palladium and platinum inks, which could remove the perceived risk of transmutation under the heavy neutron flux that we may have with the Au (to Hg, then to Pb) or the Ag (to Cd) metallic inks currently used in LTCC devices.
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  • On Humorby Luigi Pirandello; A. Iliano; D. P. Testa

    Review by: Roberto Severino  

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  • Absence of Neutralizing Antibodies to Interferon in Condyloma Acuminata and Cancer Patients Treated with Natural Human Leukocyte Interferon

    Testa, D.   Liao, M.-J.   Axelrod, H. R.   Kuchler, M.   Yip, Y.-K.   Kirkbright, E.  

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