Since the signatures of ITER divertor Procurement Arrangements, material purchases, process qualification as well as manufacturing of full-scale prototypes have progressed. This paper provides a ...brief summary of the ITER divertor materials, the requirements for these materials, and the requirements for manufacturing and inspection of the divertor components. Experiences to be acquired through the prototype manufacturing activities are also discussed.
In ITER, as in any tokamak, the first wall and divertor plasma-facing components (PFC) must provide adequate protection of in-vessel structures, sufficient heat exhaust capability and be compatible ...with the requirements of plasma purity. These functions take on new significance in ITER, which will combine long pulse, high power operation with severe restrictions on permitted core impurity concentrations and which, in addition, will produce transient energy loads on a scale unattainable in today’s devices. The current ITER PFC design has now reached a rather mature stage following the 2007 ITER Design Review. This paper presents the key elements of the design, reviews the physics drivers, essentially thermal load specifications, which have defined the concept and discusses a selection of material and design issues.
Crack formation in an ITER-reference tungsten grade was examined under single thermal shock loading. Typically two sorts of cracks, major cracks and microcracks, were observed at the loaded surfaces. ...The microstructures were quantified and the formation mechanisms were discussed. The major cracks were generated due to the brittleness of the tungsten material and microcracks were formed in a process which was initiated by plastic deformation at high temperature. The plastic deformation caused also surface elevation of the loaded area. At more intense thermal shock loading conditions, the microcracks disappeared and surface modifications due to recrystallization was observed.
Transplantation across blood group antigen and human leukocyte antigen (HLA) barriers are immunologically high risk. Both splenectomy and rituximab injection were developed to overcome those ...immunological barriers. The idea behind these treatments is to control B‐cell immunity before and after renal transplantation and antibody production. Between January 2001 and December 2004, recipients underwent pretransplant double‐filtration plasmapheresis (DFPP) and splenectomy at the time of transplantation in the ABO‐incompatible group (ABO‐I‐SPX; n= 45). From January 2005 to June 2009, a low dose of rituximab was given as an alternative to splenectomy (ABO‐I‐RIT; n = 57). As a control group, we selected 83 cases of ABO‐C living‐donor kidney transplantation between January 2001 and December 2007 (ABO‐C). We compared the graft survival rate and chronic antibody‐mediated rejection (C‐AMR) rate between ABO‐C and ABO‐I kidney transplantation with induction treatment. C‐AMR rates 2 years after the operation were 8.8, 3.5 and 28.9%, and de novo donor‐specific anti‐HLA antibody (DSHA) positive rates were 2.2, 1.7 and 18.1% in the ABO‐I‐SPX, ABO‐I‐RIT and ABO‐C groups, respectively. The ABO‐C group showed the highest rate of C‐AMR and de novo DSHA. B‐cell depletion protocols, such as splenectomy or rituximab administration, reduced C‐AMR after kidney transplantation.
The authors compare the chronic antibody‐mediated rejection rate between ABO‐compatible and ABO‐incompatible kidney transplantation and note that although there is no influence of anti‐blood group antibodies after more than 6 months postsurgery, the ABO‐compatible group shows the highest rate of chronic antibody‐mediated rejection and de novo donor‐specific anti‐HLA antibody.
In order to develop and validate the high performance tungsten monoblock technology, the full-tungsten divertor qualification program was defined. As the first step, small-scale mock-ups were ...manufactured and successfully tested under the required high heat flux loads. The test results demonstrated that the technology is available in Japan and Europe. Post-tests observation of the loaded W monoblocks showed generation of self-castellation – a crack along coolant tube axis. The cause of the self-castellation was discussed and a tungsten material characterization program is being developed with the objective to understand mechanical properties that influence the occurrence of the self-castellation.
Physics basis for the first ITER tungsten divertor Pitts, R.A.; Bonnin, X.; Escourbiac, F. ...
Nuclear materials and energy,
August 2019, 2019-08-00, 2019-08-01, Letnik:
20, Številka:
C
Journal Article
Recenzirano
Odprti dostop
•Reviews the fundamental physics aspects of the first ITER W divertor and defines the required operational lifetime within the Staged Approach.•Uses the ITER divertor SOLPS simulation database to ...establish the target peak heat flux and neutral pressure burning plasma operating domain.•Assesses consequences of narrow SOL heat flux channels, fluid drifts, component shaping and 3D magnetic fields for ELM control.•Uses W recrystallization to define an operational budget and shows that heat fluxes ∼50% higher than previously assumed may be acceptable.•Shows that Ne and N should be equally good as seed impurities and suggests that very strong ELM mitigation will be required at high performance.•Provides a list of key outstanding R&D areas to consolidate the divertor physics basis in the period up to ITER operation.
On the eve of component procurement, this paper discusses the present physics basis for the first ITER tungsten (W) divertor, beginning with a reminder of the key elements defining the overall design, and outlining relevant aspects of the Research Plan accompanying the new “staged approach” to ITER nuclear operations which fixes the overall divertor lifetime constraint. The principal focus is on the main design driver, steady state power fluxes in the DT phases, obtained from simulations using the 2-D SOLPS-4.3 and SOLPS-ITER plasma boundary codes, assuming the use of the low Z seeding impurities nitrogen (N) and neon (Ne). A new perspective on the simulation database is adopted, concentrating purely on the divertor physics aspects rather than on the core-edge integration, which has been studied extensively in the course of the divertor design evolution and is published elsewhere. Emphasis is placed on factors which may increase the peak steady state loads: divertor target shaping for component misalignment protection, the influence of fluid drifts, and the consequences of narrow scrape-off layer heat flux channels. All tend to push the divertor into an operating space at higher sub-divertor neutral pressure in order to remain at power flux densities acceptable for the target material. However, a revised criterion for the maximum tolerable loads based on avoidance of W recrystallization, sets an upper limit potentially ∼50% higher than the previously accepted value of ∼10 MW m−2, a consequence both of the choice of material and the finalized component design. Although the simulation database is currently restricted to the 2-D toroidally symmetric situation, considerable progress is now also being made using the EMC3-Eirene 3-D code suite for the assessment of power loading in the presence of magnetic perturbations for ELM control. Some new results for low input power corresponding to the early H-mode operation phases are reported, showing that even if realistic plasma screening is taken into account, significant asymmetric divertor heat fluxes may arise far from the unperturbed strike point. The issue of tolerable limits for transient heat pulses is an open and key question. A new scaling for ELM power deposition has shown that whilst there may be more latitude for operation at higher current without ELM control, the ultimate limit is likely to be set more by material fatigue under large numbers of sub-threshold melting events.
Objectives
The association between anticholinergic load-based Anticholinergic Risk Scale scores and nutritional status is unclear in Japanese patients. The aim of this study was to establish whether ...anticholinergic load affects the nutritional status of geriatric patients in convalescent stages.
Design
Retrospective longitudinal cohort study.
Setting
Convalescent rehabilitation wards.
Participants
Of the 1490 patients aged ≥65 years who were discharged from convalescent rehabilitation wards between July 2010 and October 2018, 908 patients met the eligibility criteria. They were categorized according to the presence or absence of increased anticholinergic load from admission to discharge.
Measurements
Demographic data, laboratory data, the Functional Independence Measure were analyzed between the groups. The primary outcome was Geriatric Nutritional Risk Index (GNRI) at discharge. Multiple linear regression analysis was performed to analyze the relationship between anticholinergic load and GNRI at discharge.
Results
Multiple linear regression analysis after adjusting for confounding factors revealed that anticholinergic load was independently and negatively correlated with GNRI at discharge. Particularly, the use of chlorpromazine, hydroxyzine, haloperidol, metoclopramide, risperidone, etc. increased significantly from admission to discharge.
Conclusion
Increased anticholinergic load during hospitalization may be a predictor of nutritional status in geriatric patients.
Sodium and, in a lesser way, potassium atomic components of surface-bounded exospheres are among the brightest elements that can be observed from the Earth in our Solar System. Both species have been ...intensively observed around Mercury, the Moon and the Galilean Moons. During the last decade, new observations have been obtained thanks to space missions carrying remote and in situ instrumentation that provide a completely original view of these species in the exospheres of Mercury and the Moon. They challenged our understanding and modelling of these exospheres and opened new directions of research by suggesting the need to better take into account the relationship between the surface-exosphere and the magnetosphere. In this paper, we first review the large set of observations of Mercury and the Moon Sodium and Potassium exospheres. In the second part, we list what it tells us on the sources and sinks of these exospheres focusing in particular on the role of their magnetospheres of these objects and then discuss, in a third section, how these observations help us to understand and identify the key drivers of these exospheres.
•The optimized ITER divertor design is presented.•Shaping of vertical target design was validated by 3D field line tracing calculation and thermos-mechanical analysis.•At the monoblock level, 0.5 mm ...deep toroidal bevel was implemented and a reduction of the thickness down to 6 mm was demonstrated to be acceptable.
The shaping of the ITER divertor vertical targets has been refined as a consequence of manufacturing and engineering considerations during the prototype manufacturing activities. In this paper, the optimized ITER divertor design is presented together with design validation by 3D field line tracing calculation and thermo-mechanical analysis by finite element calculations. Furthermore, the reduction of W monoblock armour thickness to 6 mm is also discussed.
Intraplaque hemorrhage in the carotid artery is related to an increased risk of cerebrovascular ischemic events. We aimed to investigate whether quantitative susceptibility mapping can characterize ...carotid artery plaque components and quantify the severity of intraplaque hemorrhage.
For this ex vivo quantitative susceptibility mapping study, 9 carotid endarterectomy specimens were imaged on a 3T MR imaging scanner using a 3D multi-echo gradient-echo sequence and a microscopy coil. The samples were examined histologically using immunostains, including glycophorin A and Prussian blue. The areas of erythrocytes, iron deposits, calcification, and fibrous matrices observed on stained sections were compared with quantitative susceptibility mapping findings and their mean susceptibility values.
Intraplaque hemorrhage and iron deposits were observed only in areas hyperintense on quantitative susceptibility mapping; calcifications and fibrous matrices were prevalent in hypointense areas. The mean susceptibility values for necrotic cores with intraplaque hemorrhage but no iron deposits, cores with iron deposits but no intraplaque hemorrhage, cores without either intraplaque hemorrhage or iron deposits, and cores with calcification were 188 ± 51, 129 ± 49, -11 ± 17, and -158 ± 78 parts per billion, respectively. There was a significant difference in the mean susceptibility values among the 4 histologic components (
< .01). The mean susceptibility values of the whole plaque positively correlated with the percentage area positive for glycophorin A (
= 0.65,
< .001) and Prussian blue (
= 0.47,
< .001).
Our findings suggest that quantitative susceptibility mapping can characterize the composition of carotid plaques and quantify the degree of intraplaque hemorrhage and iron deposits.
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