420 research outputs found
The superconducting proposal for the CS magnet system of FAST: a preliminary analysis of the heat load due to AC losses
FAST (Fusion Advanced Studies Torus), the Italian proposal of a Satellite
Facility to ITER, is a compact tokamak (R = 1.82 m, a = 0.64 m,
triangularity = 0.4) able to investigate non-linear dynamics effects
of -particle behavior in burning plasmas and to test technical
solutions for the first wall/divertor directly relevant for ITER and DEMO.
Currently, ENEA is investigating the feasibility of a superconducting solution
for the magnet system. This paper focuses on the analysis of the CS (Central
Solenoid) magnet thermal behavior. In particular, considering a superconducting
solution for the CS which uses the room available in the resistive design and
referring to one of the most severe scenario envisaged for FAST, the heat load
of the CS winding pack due to AC losses is preliminarily evaluated. The results
provide a tentative baseline for the definition of the strand requirements and
conductor design, that can be accepted in order to fulfil the design
requirements.Comment: 15 pages, 5 figure
Diabetes is not a negative prognostic factor for 30-days mortality after surgery for acute type A aortic dissection
BackgroundThe correlation between diabetes and aortic dissection is not fully understood yet, although in literature many studies have suggested that there may be an association between the two conditions. The purpose of this study is to evaluate whether diabetes represents a short- and long-term risk factor for mortality from type A acute aortic dissection.Materials and methodsA total of 340 patients with the diagnosis of type A acute aortic dissection underwent aortic surgery between January 2002 and March 2023. The sample was divided into 2 cohorts according to the presence of diabetes (n = 34) or not (n = 306).ResultsThe mean age was 66 (+/- 12.4) years and 60.9% were male. The primary endpoint was 30-day mortality. Hospital mortality was 12 (35.3%) for the diabetes group and 70 (22.9%) for nondiabetes group (P = 0.098). Overall survival at 10 years was 48.3% [95% confidence interval (CI): 41.6-54.7%], while the 10-year survival for people with diabetes was 29.5% (95% CI: 13.2-47.9%) and for nondiabetes group 50.6% (95% CI: 43.4-57.3%) (Log-rank, P = 0.024).ConclusionDiabetes was not found to be a risk factor associated with 30-day mortality in patients undergoing surgery for type A acute aortic dissection. It was a risk factor for long-term survival, but this may be related to diabetes complications.Video Abstract1_urfofl4gKaltur
In-situ Undisturbed Sand Sampling by Radial Freezing for Liquefaction Analysis
The authors experimented in laboratory that if radial freezing with free drainage is performed under an effective confining pressure of 100 kPa only an increase of the order of 0.5% of volumetric strain takes place going from the unfrozen to the frozen condition. The sample comes back to the original dimension after thawing. The displacements of the sample were measured by radiographs of a lead shot network properly built inside the sample. The technique suggested by Yoshimi and al. (1977) to freeze in situ a column of saturated sands was also verified and optimized in laboratory by simulating in a full scale test the site conditions. Finally 3.10 m length and 55 cm. diameter sample of saturated sand was frozen at a well studied site by radial freezing technique, then pulled out from the ground by a crane, sawed and stored in a freezer for future laboratory tests
Application of kaolin and italian natural chabasite-rich zeolitite to mitigate the effect of global warming in vitis vinifera l. Cv. sangiovese
High temperatures and the anomalous distribution of rainfall during the growing season may have a negative impact on grapevine yield and berry composition. In recent years, many studies have focused on the application of agronomical techniques to reduce the negative impact of heat waves on secondary metabolites such as phenols. In particular, treatments with kaolin have shown positive effects on reducing canopy temperatures, enhancing the accumulation of anthocyanins. In regard to the above, three treatments were evaluated: untreated control (C), kaolin (CAO), and chabasite-rich zeolitites (ZEO) applications on cv. Sangiovese in order to verify the cooling effects on leaves and bunches, and the impact on gas exchange, yield parameters, berry composition, and on both chemical and sensory notes of wine. Minerals were sprayed twice around the veraison on the entire canopy at a 3% concentration. The results showed that the application of the minerals was able to reduce the berry temperatures in both years of the trial as compared to the untreated control (C), without affecting vine gas exchange, yield, and soluble solid accumulation. Furthermore, the cooling effect determined an increase in anthocyanin on both the grapes and the wine. At testing, CAO and ZEO wines stood out regarding greater color intensity and were preferred by the judges
Intercostal artery's access for type II endoleak embolization
Endoleaks represent a main issue of endovascular approach of thoracic aorta diseases and their treatment continue to be challenging. According to some authors, type II endoleaks sustained by intercostal arteries should not be treated because of the technical difficulties. However, the persistence of a pressurized aneurysmal may confer an ongoing risk of enlargement and/or aortic rupture. We describe the successful treatment of type II endoleak in 2 patients with an intercostal artery's access. In both cases, the endoleak was discovered during follow-up and was treated with its direct coil embolization under local anaesthesia
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
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