1,285 research outputs found
Antropologia della disponibilità. Dal sistema della distruzione all’armonia della speranza
No full textLABATE, Beatriz C. et al. (orgs). Drogas e cultura: novas perspectivas
No full textLABATE, Beatriz C. et. al. (Orgs). Drogas e cultura: novas perspectivas. Salvador: EDUFBA, 2008. 440p.A coletânea Drogas e Cultura: novas perspec-tivas, organizada por Beatriz C. Labate, San-dra Goulart, Maurício Fiore, Edward MacRaee Henrique Carneiro, apresenta-se como ummanifesto do Núcleo de Estudos Interdiscipli-nares sobre Psicoativos (NEIP) e oferece umaimportante contribuição para os pesquisadorese estudantes interessados na temática das “dro-gas” – tema com raras incursões intelectuaisque a tratem sem preconceito – onde a perce-bem como um fenômeno complexo, multidi-mensional e que necessita de uma abordagemmultidisciplinar.
The role of visual and spatial working memory informing mental models derived from survey and route descriptions
No full textThis study examines the involvement of spatial and visual working memory (WM) in the
construction of flexible spatial models derived from survey and route descriptions. Sixty
young adults listened to environment descriptions, 30 from a survey perspective and the
other 30 from a route perspective, while they performed spatial (spatial tapping [ST]) and
visual (dynamic visual noise [DVN]) secondary tasks – believed to overload the spatial and
visual working memory (WM) components, respectively – or no secondary task (control,
C). Their mental representations of the environment were tested by free recall and a
verification test with both route and survey statements. Results showed that, for both
recall tasks, accuracy was worse in the ST than in the C or DVN conditions. In the
verification test, the effect of both ST and DVN was a decreasing accuracy for sentences
testing spatial relations from the opposite perspective to the one learnt than if the
perspective was the same; only ST had a stronger interference effect than the C condition
for sentences from the opposite perspective from the one learnt. Overall, these findings
indicate that both visual and spatial WM, and especially the latter, are involved in the
construction of perspective-flexible spatial models
Die notwendige Nichtaktualität des Fundaments. Anmerkungen aus der Sicht von Ernst Blochs „Naturrecht und menschliche Würde“
No full textLa necessaria inattualità del fondamento. Note a partire da Diritto naturale e dignità umana di Ernst Bloch
No full textDetailed characterization of the early x-ray emission of a plasma produced by point-like laser irradiation of solid Al targets
No full textA study of the dynamics of the x-ray emission from a point-like Al plasma produced by tight-focusing laser irradiation of a thick target is reported. Two-dimensional maps of the x-ray emission calculated at selected wavelengths show that, due to the rapid expansion cooling, x-ray emission mostly originates from a thin spatial layer. These properties enabled the results of the simulations to be compared with time-resolved x-ray spectra obtained under well-controlled experimental conditions. The outcome of this comparison is discussed in details, in view of the results reported in a recently published Letter [L. A. Gizzi, C. A. Cecchetti, M. Galimberti, A. Giulietti, D. Giulietti, L. Labate, S. Laville, and B. Tomassini, Phys. Plasmas 10, 4601 (2003)]. Moreover, the x-ray-reabsorption issues and the role of the Doppler decoupling mechanism in the presence of the strong velocity gradient typical of our experimental condition are discussed, also in view of a possible dedicated experiment. (c) 2005 American Institute of Physics
A command governor approach to plasma shape control
No full textThe paper deals with the application of the socalled Command Governor (CG) approach to the shape control of plasmas in thermonuclear fusion reactors. A primal internal loop controlling the plasma-wall gaps is designed first and a CG device is then tuned to modify, whenever necessary, the reference to the primal loop, taking into account constraints due to voltages saturations on the converters, currents limitations in the active coils, force limits on the mechanical structures, minimum clearance between the plasma and the vacuum chamber wall, maximum induced forces on coils. The reference signal modification is accomplished through an online optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon as usual in model predictive paradigms. The ITER (International Thermonuclear Experimental Reactor) tokamak is assumed as a case study. Numerical simulations are carried out on a numerical nonlinear model taking into account almost a hundred of constraints. ©2009 IEEE
Constrained plasma shape control in ITER
No full textThis paper presents an application of a novel constrained control methodology known as Command Governor (CG) to the shape control of plasmas in thermonuclear fusion reactors. The CG strategy is based on predictive control ideas and consists in modifying, whenever necessary, the reference signal supplied to a primal internal loop controlling the plasma distance from the internal walls of the tokamak, taking into account constraints due to voltages saturations on the converters, currents limitations in the active coils for magnetic confinement, force limits on the mechanical structures, minimum clearance between the plasma and the vacuum chamber wall, maximum induced forces on coils. The reference signal modification is accomplished through an on-line optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon. A numerical example with about a hundred of constraints, is developed with reference to ITER
A Command Governor Approach to Plasma Shape Control
No full textThe paper deals with the application of the socalled Command Governor (CG) approach to the shape control of plasmas in thermonuclear fusion reactors. A primal internal loop controlling the plasma-wall gaps is designed first and a CG device is then tuned to modify, whenever necessary, the reference to the primal loop, taking into account constraints due to voltages saturations on the converters, currents limitations in the active coils, force limits on the mechanical structures, minimum clearance between the plasma and the vacuum chamber wall, maximum induced forces on coils. The reference signal modification is accomplished through an online optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon as usual in model predictive paradigms. The ITER (International Thermonuclear Experimental Reactor) tokamak is assumed as a case study. Numerical simulations are carried out on a numerical nonlinear model taking into account almost a hundred of constraints
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