Current (re-)Distribution inside an ITER Full-Size Conductor: a Qualitative Analysis

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Mechanical analysis of the ENEA TF coil proposal for the EU DEMO fusion reactor

The design of the superconducting magnet system of the European DEMO fusion reactor is currently being pursued in the framework of the EUROfusion Magnets Work Package (WPMAG). Three alternative winding pack (WP) options for the Toroidal Field Coils (TFCs) are being proposed by different research units, each featuring a different conductor manufacturing technology (react-and-wind vs. wind-and-react) or winding layout (layer vs. pancake). One of the options (namely, WP#2), proposed by Italian ENEA, features a layer-wound WP design adopting a wind-and-react conductor with rectangular cross section with high aspect ratio, obtained squeezing an initially circular conductor. In order to assess the capability of all the TFC components to withstand the electromagnetic loads due to the huge Lorentz forces without any structural failure during the magnet lifetime, the mechanical analysis of the 2016 version of the WP#2 design option is performed here applying a hierarchical approach herein defined as the Stress Recovery Tool (SRT): the Finite Element Analysis (FEA) of a whole magnet (including the casing) is performed at a low computational cost adopting a coarse WP model with smeared (homogenized) properties. The displacements computed on the smeared WP are then used as boundary conditions for a refined FEA of some WP slices, located in selected (critical) poloidal positions, where all the conductors detailed features (jacket, insulations) are properly accounted for

Stability in a long length NbTi CICC

A crucial issue for a superconducting coil in order to be safely used in the magnetic system of a fusion reactor is stability against all foreseen disturbances. To simulate the fusion machine conditions, including off-normal events, e.g. plasma disruptions, the energy deposition has to be spread over a "long length" cable in conduit conductor (CICC) and a background magnetic field is needed. We have therefore designed and built an experiment consisting of an instrumented NbTi test module inserted in a pair of co-axial pulsed copper coils. A 0.6 m diameter superconducting coil provides a background magnetic field up to 3 T. Calibration of the energy inductively coupled between the pulsed coils and the module has been obtained measuring the system temperature increase just after the pulse by means of thermometers positioned along the conductor. Stability vs. operating current I/sub op/ has been examined for different helium temperatures and different background magnetic fields. The finite element code Gandalf for the stability and quenching transients analysis in forced flow cooled superconducting coils has been run to check the matching with the experimental results. (3 refs)

Comparison Between Single Early-loaded Implants With Sandblasted Acidetched (Sa) Surface Versus Sa Surface Modified With Ph Buffering Agent (Soi): Four-month Data From a Split-mouth, Multicentre Randomized Controlled Trial

PURPOSE. To compare implant survival and success rates and implant stability quotient (ISQ) values of early-loaded single implants with sandblasted acid-etched (SA, control group) surface versus implants with SA surface modified with pH buffering agent (SOI, test group). MATERIALS AND METHODS. This study was designed as multicentre, split-mouth, randomized controlled trial to evaluate implant and prosthesis survival rates, complications, and implant stability quotient (ISQ) in any partially edentulous subject requiring at least two single implant-supported crowns. A one-stage implant placement procedure was used, and implants were randomized after implant site preparation. ISQ values were eva-luated for each implant, at baseline and then every week up to 8 weeks after surgery, and finally at definitive crown delivery (12 weeks after implant placement). RESULTS. Overall, 62 patients from 9 centres were enrolled in this study. One patient dropped out from the study at 8 weeks. In the first 12 weeks of observation, 2 implants failed, both in the SA group, the difference not being statistically significant (P = 0.5). No prosthesis failure occurred up to 4 months after fitting. Five complications were expe-rienced, 3 in the SA group and 2 in the SOI group. The difference between groups was not statistically significant (OR = 0.66, 95% CI: 0.11 to 4.07; P = 0.650). Of these complications, loss of stability without rotation was observed in 2 implants from the SOI group and 2 implants from the SA group, all in the third and fourth weeks of measurements. All the implants were submerged and successfully osseointegrated at the twelfth week. The last complication was an SA implant screw loosening, which was resolved chair-side. The baseline mean ISQ values were 76.57 ± 7.54 (95% CI 74.69 to 78.44) in the SA group and 75.92 ± 7.69 (95% CI 73.89 to 77.73) in the SOI group. The mean ISQ values at 12 weeks were 79.17 ± 7.83 (95% CI 77.03 to 81.29) and 78.82 ± 8.80 (95% CI 76.42 to 81.21) in the SA and SOI groups, respectively. Mixed-effects modelling revealed a statistically significant difference between groups over time, with slightly lower ISQ values for the SOI group (-0.65; 95% CI-1.14 to-0.15). Statistically significant differences were also estimated among centres (P <0.001). CONCLUSIONS. Within the limitations of the present preliminary report, it is possible to conclude that both implants can be successfully loaded early

DC and transient current distribution analysis from self-field measurements on ITER PFIS conductor

Current reconstruction in cable-in-conduit conductors (CICC) cables is a crucial issue to determine cables performance in working conditions, and must be performed using inverse problem approaches as direct measurement is not feasible. The current distribution has been studied for the ITER Poloidal Field Insert Sample (PFIS) conductor using annular arrays of Hall probes placed in three different locations along the sample during the test campaign at the SULTAN facility. The measurement apparatus is also described in the paper, together with the approach to current reconstruction

To Splint or Not to Splint Short Dental Implants Under the Same Partial Fixed Prosthesis? One-year Post-loading Data From a Multicentre Randomised Controlled Trial

PURPOSE. To compare the clinical outcomes of two adjacent 6-mm-long dental implants splinted under the same prosthesis (control group) versus two identical implants sup-porting single crowns (test group). MATERIALS AND METHODS. Forty-seven patients with edentulous posterior (premolars and/or molars) jaws received two adjacent 6-mm-long dental implants, which were sub-merged. Four months later, at impression taking, patients were randomised to receive splinted or unsplinted definitive cemented metal-composite prostheses. Unfortunately, four patients died before randomisation and three patients lost five implants, so only 40 patients were randomised, according to a parallel-group design, to have both implants splinted under the same partial fixed prosthesis (19 patients) or with two single crowns (21 patients). Outcome measures were: prosthesis and implant failures, any complica-tions, peri-implant marginal bone level changes and patient satisfaction. Patients were followed-up to 1 year after loading. RESULTS. One patient from the splinted group dropped out. No implant failures occurred after randomisation. One complication occurred in the unsplinted group versus no complications at splinted implants, the difference not being statistically different (Fisher’s exact test P = 1.000; difference in proportions =-0.04; 95% CI-0.16 to 0.09). Both groups presented significant peri-implant marginal bone loss at 1 year after loading (P<0.05), respectively-0.36 (0.45) mm at splinted implants and-0.17 (0.31) mm at unsplinted implan-ts, but there were no statistically significant differences between the two groups (mean difference 0.19 mm; 95% CI-0.10 to 0.48; P = 0.194). All patients were fully or reasonably satisfied with the treatment, with the exception of two patients, both from the splinted group: one patient was not sure about the aesthetics, and another would not undergo the same treatment again. CONCLUSIONS. The present data seems to suggest that up to 1 year after loading the prognosis of short implants, mostly placed in mandibles characterised by dense bone quality, may not be influenced by splinting or not under the same fixed prostheses. Howe-ver, these preliminary results need to be confirmed by larger trials with follow-ups of at least 5 years

Rhizobium strains competitiveness on bean nodulation in Cerrado soils.

ABSTRACT: The objective of this work was to identify the most competitive and effective Rhizobium strains in order to increase common bean yield by nitrogen fixation as alternative or complementation to the nitrogen fertilization. Competitiveness tests were lead in axenic conditions, in Cerrado soil pots and in three field experiments, with native Rhizobium strains that were previously identified, according to their effectiveness and genetic variability. The identification of strains in nodules was performed using serological tests (axenic conditions) ? agglutination and enzyme linked immunosorbent (Elisa) assays ? and random amplified polymorfic DNA (RAPD) (Cerrado soil). Plant yield was determined using the dry weight (greenhouse conditions), total N and grain yield (field experiments). Among the analyzed Rhizobium strains, native strain SLA 2.2 and commercial strain CIAT 899 were the dominant nodules in plants of the most productive plots, presenting yield productivity similar or higher to those obtained in treatments where 20 kg ha-1 of N were applied. RESUMO: O objetivo deste trabalho foi identificar as estirpes de Rhizobium mais efetivas e competitivas, a fim de maximizar a produtividade do feijoeiro por meio da fixação de nitrogênio, como alternativa à adubação nitrogenada. Foram conduzidos testes de competitividade em condições axênicas, em vasos com solo do Cerrado e em três experimentos de campo, com estirpes de Rhizobium nativas, previamente selecionadas quanto à efetividade e à variabilidade genética. A identificação das estirpes nos nódulos foi efetuada por meio das técnicas de aglutinação e ensaio imunoabsorvente de ligação de enzimas (Elisa), em condições de casa de vegetação, e pela técnica de DNA polimórfico amplificado ao acaso (RAPD), em solo de Cerrado. A produtividade das plantas foi determinada pela produção de matéria seca, teor de N e produção de grãos (condições de campo). A estirpe nativa SLA 2.2 e a estirpe comercial CIAT 899 foram dominantes nos nódulos das plantas das parcelas mais produtivas, com índices de produtividade iguais ou superiores aos obtidos nos tratamentos em que foram aplicados 20 kg ha-1 de N