1,721,097 research outputs found
American Solitudes: Individual, National, Transnational. Proceedings of the XVIII International AISNA Conference, Bari October 5-8 2005
No full textFull 3 D stress analyses of complex shaped electrical busbars under high electromagnetic load
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Thermal fluxes due to plasma-wall interactions: Experimental measurements and numerical analyses
No full textThe experimental results obtained from thermonuclear fusion devices highlight an uneven thermal flux distribution on the first wall, due to enhanced localized plasma-wall interactions. A numerical model to evaluate these thermal fluxes was implemented taking into account both the axisymmetric and the localized energy contributions. This paper illustrates the model, its approximations and the required input data to be taken from experimental measurements. The results of the thermal nonlinear dynamic analyses carried out for the RFX first wall and vacuum vessel are presented and compared with the vessel temperature measurements acquired during the experimental sessions. The simulations of the thermal responses show that more than 40% of the total plasma energy is concentrated in the region where the plasma-wall interaction is enhanced by the presence of locked modes
RFX first wall thermal power handling: 3D numerical models and experimental validations
No full textOne of the emerging issues for future thermonuclear devices is the non-uniform power deposition on the first wall or divertor surfaces. The localized peaks of power are detrimental both for the lifetime of the plasma facing components and for plasma heating and confinement. The thermal monitoring of the first wall can be done with temperature measurements acquired during the experiments by means of thermocouples and/or infrared camera images. If the measurement system is integrated with analytical or numerical models, it is possible to estimate the applied thermal loads and to obtain a thorough knowledge of the thermal behaviour of the first wall and vacuum vessel system. The numerical model developed for the RFX machine is hereby described and validated by means of comparisons with IR camera and thermocouple temperature measurements
Development of a power electrode for plasma biasing on RFX
No full textA movable power electrode has been developed on the RFX experiment to modify the radial electric field at the edge of the plasma configuration. The electrode insertion head is a mushroom shaped limiter made of a carbon-carbon composite, and boron nitride is used as insulating material to be exposed to the plasma. The power electrode is designed to carry a 10 kA impulsive current and is insulated for 10 kV dc. The current into the electrode is driven by a power supply based on capacitor banks, and protective actions to cope with fault conditions have been implemented. The design of the electrode supporting structure has been done by using 3D finite element analyses, performed to evaluate the dynamic response of the system subjected to impulsive electromagnetic loads. The system has been used on the RFX experiment, showing the expected capability and flexibility. The current and voltage electrode waveforms are reported and discussed as far as the experimental results are concerned. Displacements of the electrode stiffening structure under electromagnetic load have been measured and compared to the numerical results
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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