| 1. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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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.
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| 2. |
- Romanelli, F, et al.
(författare)
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Overview of the JET results
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
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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.
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| 3. |
- de Sa Salomao, Andre Luis, et al.
(författare)
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Engineered ecosystem for on-site wastewater treatment in tropical areas
- 2012
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 66:10, s. 2131-2137
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Tidskriftsartikel (refereegranskat)abstract
- There is a worldwide demand for decentralized wastewater treatment options. An on-site engineered ecosystem (EE) treatment plant was designed with a multistage approach for small wastewater generators in tropical areas. The array of treatment units included a septic tank, a submersed aerated filter, and a secondary decanter followed by three vegetated tanks containing aquatic macrophytes intercalated with one tank of algae. During 11 months of operation with a flow rate of 52 L h(-1), the system removed on average 93.2% and 92.9% of the chemical oxygen demand (COD) and volatile suspended solids (VSS) reaching final concentrations of 36.3 +/- 12.7 and 13.7 +/- 4.2 mg L-1, respectively. Regarding ammonia-N (NH4-N) and total phosphorus (TP), the system removed on average 69.8% and 54.5% with final concentrations of 18.8 +/- 9.3 and 14.0 +/- 2.5 mg L-1, respectively. The tanks with algae and macrophytes together contributed to the overall nutrient removal with 33.6% for NH4-N and 26.4% for TP. The final concentrations for all parameters except TP met the discharge threshold limits established by Brazilian and EU legislation. The EE was considered appropriate for the purpose for which it was created.
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| 4. |
- Linnér, Rikard, et al.
(författare)
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Early adrenaline administration does not improve circulatory recovery during resuscitation from severe asphyxia in newborn piglets.
- 2012
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Ingår i: Resuscitation. - : Elsevier BV. - 1873-1570 .- 0300-9572. ; 83:10, s. 1298-1303
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Tidskriftsartikel (refereegranskat)abstract
- AIM OF THE STUDY: : To investigate the effects of early intravenous adrenaline administration on circulatory recovery, cerebral reoxygenation, and plasma catecholamine concentrations, after severe asphyxia-induced bradycardia and hypotension. METHODS: One-day old piglets were left in apnoea until heart rate and mean arterial pressure were less than 50min(-1) and 25mmHg, respectively. They randomly received adrenaline, 10 μg kg(-1) (n=16) or placebo (n=15) and were resuscitated with air ventilation and, when needed, closed-chest cardiac massage (CCCM). Eight not asphyxiated animals served as time controls. RESULTS: CCCM was required in 13 piglets given adrenaline and in 13 given placebo. Time to return of spontaneous circulation was: 72 (66-85) s vs. 77 (64-178) s [median (quartile range)] (p=0.35). Time until cerebral regional oxygen saturation (CrS(O2)) had increased to 30% was 86 (79-152) s vs. 126 (88-309) s (p=0.30). The two groups did not differ significantly in CrS(O2), heart rate, arterial pressure, right common carotid artery blood flow, or number of survivors: 13 and 11 animals. Plasma concentration of adrenaline, 2.5min after resuming ventilation, was 498 (268-868) nmol l(-1)vs. 114 (80-306) nmol l(-1) (p=0.01). Corresponding noradrenaline concentrations were 1799 (1058-4182) nmol l(-1)vs. 1385 (696-3118) nmol l(-1) (ns). In the time controls, the concentrations were 0.4 (0.2-0.6) nmol l(-1) of adrenaline and 1.8 (1.3-2.4) nmol l(-1) of noradrenaline. CONCLUSION: The high endogenous catecholamine levels, especially those of noradrenaline, may explain why early administered adrenaline did not significantly improve resuscitation outcome.
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