| 1. |
- Abel, I, et al.
(författare)
-
Overview of the JET results with the ITER-like wall
- 2013
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
-
Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
|
|
| 2. |
- Romanelli, F, et al.
(författare)
-
Overview of the JET results
- 2011
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
-
Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
|
|
| 3. |
|
|
| 4. |
- Aad, G., et al.
(författare)
-
- 2013
-
Tidskriftsartikel (refereegranskat)
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Santaliestra-Pası´as, AM, et al.
(författare)
-
Increased sedentary behaviour is associated with unhealthy dietary patterns in European adolescents participating in the HELENA study
- 2014
-
Ingår i: European Journal of Clinical Nutrition. - : Springer Science and Business Media LLC. - 0954-3007 .- 1476-5640. ; 68:3, s. 300-308
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND/OBJECTIVES: To assess dietary patterns (DPs) in European adolescents and to examine their relationship withseveral indicators of sedentary behaviour.SUBJECTS/METHODS: A multinational cross-sectional study was carried out in 2202 adolescents (45.4% boys) aged 12.5–17.5 years. A self-reported questionnaire with information on sedentary behaviours, separately for weekdays and weekend days, and two non-consecutive 24 h-recalls were used. Principal component analysis was used to obtain DPs, and linear regression examined the association between DPs scores and sedentary behaviour.RESULTS: Four DPs for boys (‘plant based’, ‘snacking’, ‘breakfast’ and ‘health conscious’) and five DPs for girls (‘confectionary and snacking’, ‘plant based’, ‘breakfast’, ‘animal protein’ and ‘health conscious’) were obtained. Boys who spent 44 h/day watching television (TV) had lower adherence to the ‘plant based’, ‘breakfast’ and ‘health conscious’ DPs, and higher adherence to the ‘snacking’ DP. Higher computer use and internet use for recreational reason were associated with higher adherence to the ‘snacking’ DP. In girls, TV viewing and using internet for recreational reasons for 44 h/day was associated with higher adherence to the ‘confectionary and snacking’ and lower adherence with ‘health conscious’ DP. Also, studying between 2 and 4 h during weekend days was associated with lower adherence to the ‘snacking’ and with higher adherence to the ‘plant based’ and ‘breakfast’ DPs.CONCLUSION: Adolescents’ DPs are related with the time spent in several sedentary behaviours. Such findings may help to generate interventions focusing on decreasing unhealthy dietary habits and specific sedentary behaviours.
|
|
