| 1. |
- Murari, A., et al.
(författare)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 5. |
- Dramburg, S, et al.
(författare)
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EAACI Molecular Allergology User's Guide 2.0
- 2023
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Ingår i: Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology. - 1399-3038. ; 3434 Suppl 28, s. e13854-
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Litaudon, X., et al.
(författare)
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EUROfusion contributions to ITER nuclear operation
- 2024
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Ingår i: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 64:11
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Tidskriftsartikel (refereegranskat)abstract
- ITER is of key importance in the European fusion roadmap as it aims to prove the scientific and technological feasibility of fusion as a future energy source. The EUROfusion consortium of labs within Europe is contributing to the preparation of ITER scientific exploitation and operation and aspires to exploit ITER outcomes in view of DEMO. The paper provides an overview of the major progress obtained recently, carried out in the frame of the new (initiated in 2021) EUROfusion work-package called 'Preparation of ITER Operation' (PrIO). The overview paper is directly supported by the eleven EUROfusion PrIO contributions given at the 29th Fusion Energy Conference (16-21 October 2023) London, UK [www.iaea.org/events/fec2023]. The paper covers the following topics: (i) development and validation of tools in support to ITER operation (plasma breakdown/burn-through with evolving plasma volume, new infra-red synthetic diagnostic for off-line analysis and wall monitoring using Artificial Intelligence techniques, synthetic diagnostics development, development and exploitation of multi-machine databases); (ii) R&D for the radio-frequency ITER neutral beam sources leading to long duration of negative deuterium/hydrogen ions current extraction at ELISE and participation in the neutral beam test facility with progress on the ITER source SPIDER, and, the commissioning of the 1 MV high voltage accelerator (MITICA) with lessons learned for ITER; (iii) validation of neutronic tools for ITER nuclear operation following the second JET deuterium-tritium experimental campaigns carried out in 2021 and in 2023 (neutron streaming and shutdown dose rate calculation, water activation and activated corrosion products with advanced fluid dynamic simulation; irradiation of several materials under 14.1 MeV neutron flux etc).
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| 7. |
- Brkovic, S. M., et al.
(författare)
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Non-stoichiometric tungsten-carbide-oxide-supported Pt–Ru anode catalysts for PEM fuel cells – From basic electrochemistry to fuel cell performance
- 2020
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 45:27, s. 13929-13938
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Tidskriftsartikel (refereegranskat)abstract
- Durability and cost of Proton Exchange Membrane fuel cells (PEMFCs) are two major factors delaying their commercialization. Cost is associated with the price of the catalysts, while durability is associated with degradation and poisoning of the catalysts, primarily by CO. This motivated us to develop tungsten-carbide-oxide (WxCyOz) as a new non-carbon based catalyst support for Pt–Ru–based anode PEMFC catalyst. The aim was to improve performance and obtain higher CO tolerance compared to commercial catalysts. The performance of obtained PtRu/WxCyOz catalysts was investigated using cyclic voltammetry, linear scan voltammetry and rotating disk electrode voltammetry. Particular attention was given to the analysis of CO poisoning, to better understand how WxCyOz species can contribute to the CO tolerance of PtRu/WxCyOz. Improved oxidation of COads at low potentials (E < 0.5 V vs. RHE) was ascribed to OH provided by the oxide phase at the interfacial region between the support and the PtRu particles. On the other hand, at high potentials (E > 0.5 V vs. RHE) CO removal proceeds dominantly via OH provided from the oxidized metal sites. The obtained catalyst with the best performance (30% PtRu/WxCyOz) was tested as an anode catalyst in PEM fuel cell. When using synthetic reformate as a fuel in PEMFC, there is a significant power drop of 35.3 % for the commercial 30% PtRu/C catalyst, while for the PtRu/WxCyOz anode catalyst this drop is around 16 %.
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| 8. |
- Stancar, Z., et al.
(författare)
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Experimental validation of an integrated modelling approach to neutron emission studies at JET
- 2021
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Ingår i: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 61:12
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Tidskriftsartikel (refereegranskat)abstract
- An integrated modelling methodology for the calculation of realistic plasma neutron sources for the JET tokamak has been developed. The computational chain comprises TRANSP plasma transport and DRESS neutron spectrum calculations, and their coupling to the MCNP neutron transport code, bridging plasma physics and neutronics. In the paper we apply the developed methodology to the analysis of neutron emission properties of deuterium and helium plasmas at JET, and validate individual modelling steps against neutron diagnostic measurements. Two types of JET discharges are modelled-baseline-like and three-ion radio-frequency scenarios-due to their diversity in plasma heating, characteristics of the induced fast ion population, and the imprint of these on neutron emission properties. The neutron emission modelling results are quantitatively compared to the total neutron yield from fission chambers, neutron emissivity profiles from the neutron camera, neutron spectra from the time-of-flight spectrometer, and neutron activation measurements. The agreement between measured and calculated quantities is found to be satisfactory for all four diagnostic systems within the estimated experimental and computational uncertainties. Additionally, the effect of neutrons not originating from the dominating D(D, n)He-3 reactions is studied through modelling of triton burnup DT neutrons, and, in mixed D-He-3 plasmas, neutrons produced in the Be-9(D, n gamma)B-10 reaction on impurities. It is found that these reactions can contribute up to several percent to the total neutron yield and dominate the neutron activation of samples. The effect of MeV-range fast ions on the neutron activation of In-115 and Al-27 samples is measured and computationally validated.
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| 9. |
- Zivanovic, D., et al.
(författare)
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Main Memory in HPC: Do We Need More or Could We Live with Less?
- 2017
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Ingår i: Transactions on Architecture and Code Optimization. - : Association for Computing Machinery (ACM). - 1544-3973 .- 1544-3566. ; 14:1, s. Article nr 3-
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Tidskriftsartikel (refereegranskat)abstract
- An important aspect of High-Performance Computing (HPC) system design is the choice of main memory capacity. This choice becomes increasingly important now that 3D-stacked memories are entering the market. Compared with conventional Dual In-line Memory Modules (DIMMs), 3D memory chiplets provide better performance and energy efficiency but lower memory capacities. Therefore, the adoption of 3D-stacked memories in the HPC domain depends on whether we can find use cases that require much less memory than is available now. This study analyzes the memory capacity requirements of important HPC benchmarks and applications. We find that the High-Performance Conjugate Gradients (HPCG) benchmark could be an important success story for 3D-stacked memories in HPC, but High-Performance Linpack (HPL) is likely to be constrained by 3D memory capacity. The study also emphasizes that the analysis of memory footprints of production HPC applications is complex and that it requires an understanding of application scalability and target category, i. e., whether the users target capability or capacity computing. The results show that most of the HPC applications under study have per-core memory footprints in the range of hundreds of megabytes, but we also detect applications and use cases that require gigabytes per core. Overall, the study identifies the HPC applications and use cases with memory footprints that could be provided by 3D-stacked memory chiplets, making a first step toward adoption of this novel technology in the HPC domain.
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| 10. |
- Derksen, Jeroen W. G., et al.
(författare)
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European practice patterns and barriers to smoking cessation after a cancer diagnosis in the setting of curative versus palliative cancer treatment
- 2020
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Ingår i: European Journal of Cancer. - : Elsevier. - 0959-8049 .- 1879-0852. ; 138, s. 99-108
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Tidskriftsartikel (refereegranskat)abstract
- Background: Smoking cessation after a cancer diagnosis is associated with improved overall survival. Few studies have reported oncologists' cessation practice patterns, but differences between the curative and palliative settings have not been described. We aimed to study the oncologist's perceptions on patients' tobacco use, current practices and barriers to providing smoking cessation support, while distinguishing between treatment with curative (C) and palliative (P) intent.Methods: In 2019, an online 34-item survey was sent to approximately 6235 oncologists from 16 European countries. Responses were descriptively reported and compared by treatment setting.Results: Responses from 544 oncologists were included. Oncologists appeared to favour addressing tobacco in the curative setting more than in the palliative setting. Oncologists believe that continued smoking impacts treatment outcomes (C: 94%, P: 74%) and that cessation support should be standard cancer care (C: 95%, P: 63%). Most routinely assess tobacco use (C: 93%, P: 78%) and advise patients to stop using tobacco (C: 88%, P: 54%), but only 24% (P)–39% (C) routinely discuss medication options, and only 18% (P)–31% (C) provide cessation support. Hesitation to remove a pleasurable habit (C: 13%, P: 43%) and disbelieve on smoking affecting outcomes (C: 3%, P: 14%) were disparate barriers between the curative and palliative settings (p < 0.001), but dominant barriers of time, resources, education and patient resistance were similar between settings.Conclusion: Oncologists appear to favour addressing tobacco use more in the curative setting; however, they discuss medication options and/or provide cessation support in a minority of cases. All patients who report current smoking should have access to evidence-based smoking cessation support, also patients treated with palliative intent given their increasing survival.
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