758 research outputs found

    Development of an Open-GIS decision aid system for ecological and economical management of surface and groundwater resources in the Bistrita River Basin (Romania)

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    International audienceThe Bistrita River Basin (a length of 283 km, a surface of 7039 km2, a mean discharge of 65 m3/s) is one of the most important tributary of the Siret River, which is the second major affluent of the Danube River. Heavily influenced by hydraulic management and highly polluted by agricultural and urban activities in some stretches, the Bistrita river has been studied in the framework of the Diminish Project (LIFE03 ENV/ RO/000539), funded by the Life Environment Program. The project aims to support the implementation of the EU Water Framework Directive and to combat the nutrient pollution by developing an integrated, on-line, GIS-based support system for the management of the water quality in relation with human activities, using socio-economical analysis, at the scale of the river catchments. Based on modeling approaches the decisional system allows to predict which strategy will lead to the most effective reduction of nutrient concentrations within the Bistrita hydrological network and of nutrient loads transported by the Siret River into the Danube. The consequences of the nutrient pollution are discussed for two basin areas, from two points of view: i) the effects of point and diffuse pollution for surface and groundwater, on the basis of the basin response to the changing pressures over the river catchments (industrial, rural, urban, agricultural changes), ii) the economical valuation of environmental costs and cost-effectiveness of the measures, that can be proposed from socio-economic scenarios, for reaching the "good ecological status" of this river

    Maternal dietary choline deficiency alters angiogenesis in fetal mouse hippocampus

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    We examined whether maternal dietary choline modulates angiogenesis in fetal brain. Pregnant C57BL/6 mice were fed either a choline-deficient (CD), control (CT), or choline-supplemented diet (CS) from days 12 to 17 (E12-17) of pregnancy and then fetal brains were studied. In CD fetal hippocampus, proliferation of endothelial cells (EC) was decreased by 32% (p 25% decrease in the number of blood vessels in CD fetal hippocampus (p < 0.01 vs. CT and CS), with no change in total cross-sectional area of these blood vessels. Expression of genes for the angiogenic signals derived from both endothelial and neuronal progenitor cells (NPC) was increased in CD fetal hippocampus VEGF C (Vegfc), 2.0-fold, p < 0.01 vs. CT and angiopoietin 2 (Angpt2), 2.1-fold, (p < 0.01 vs. CT)). Similar increased expression was observed in NPC isolated from E14 fetal mouse brains and exposed to low (5 μM), CT (70 μM), or high choline (280 μM) media for 72 h (low choline caused a 9.7-fold increase in relative gene expression of Vegfc (p < 0.001 vs. CT and high) and a 3.4-fold increase in expression of Angpt2, (p < 0.05 vs. CT and high). ANGPT2 protein was increased 42.2% (p < 0.01). Cytosine-phosphate-guanine dinucleotide islands in the proximity of the promoter areas of Vegfc and Angpt2 were hypomethylated in low choline NPC compared to CT NPC (p < 0.01). We conclude that maternal dietary choline intake alters angiogenesis in the developing fetal hippocampus

    Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating

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    We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed ‘three-ion’ scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of 3He ions to high energies in dedicated hydrogen–deuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast 3He ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, 3He-rich solar flares.This paper is dedicated to the late P. E. M. Vandenplas, founder and first director of LPP-ERM/KMS, in recognition of his lifelong outstanding commitment to fusion research, in particular to ICRH. The support from the JET and Alcator C-Mod Teams is warmly acknowledged. We are grateful to A. Cardinali, C. Castaldo, R. Dumont, J. Eriksson, T. Fülöp, C. Giroud, C. Hellesen, S. Menmuir and M. Schneider for fruitful discussions. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement no. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This work was also supported by the US DoE, Office of Science, Office of Fusion Energy Sciences, SciDAC Center for Simulation of Wave Plasma Interactions under DE-FC02-01ER54648 and the User Facility Alcator C-Mod under DE-FC02-99ER54512. The Alcator C-Mod Team author list is reproduced from ref. 12. The JET Contributors author list is reproduced from ref. 33.Peer ReviewedPostprint (author's final draft

    Plasma–wall interaction studies within the EUROfusion consortium : progress on plasma-facing components development and qualification

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    The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful o peration of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading f acilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualificat ion and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma–material interaction as well as the study of fundamental processes. WP PFC addresses these c ritical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle lo ads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alter native scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and m icrostructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.Peer reviewe

    Plasma-wall interaction studies within the EUROfusion consortium: Progress on plasma-facing components development and qualification

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    This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma-material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.European Commission; Consortium for Ocean Leadership 633053; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

    Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

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    Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate
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