| 1. |
- Marco, Aitor, et al.
(författare)
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A Variable Structure Control Scheme Proposal for the Tokamak a Configuration Variable
- 2019
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Ingår i: Complexity. - : Hindawi Publishing Corporation. - 1076-2787 .- 1099-0526.
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Tidskriftsartikel (refereegranskat)abstract
- Fusion power is the most significant prospects in the long-term future of energy in the sense that it composes a potentially clean, cheap, and unlimited power source that would substitute the widespread traditional nonrenewable energies, reducing the geographical dependence on their sources as well as avoiding collateral environmental impacts. Although the nuclear fusion research started in the earlier part of 20th century and the fusion reactors have been developed since the 1950s, the fusion reaction processes achieved have not yet obtained net power, since the generated plasma requires more energy to achieve and remain in necessary particular pressure and temperature conditions than the produced profitable energy. For this purpose, the plasma has to be confined inside a vacuum vessel, as it is the case of the Tokamak reactor, which consists of a device that generates magnetic fields within a toroidal chamber, being one of the most promising solutions nowadays. However, the Tokamak reactors still have several issues such as the presence of plasma instabilities that provokes a decay of the fusion reaction and, consequently, a reduction in the pulse duration. In this sense, since long pulse reactions are the key to produce net power, the use of robust and fast controllers arises as a useful tool to deal with the unpredictability and the small time constant of the plasma behavior. In this context, this article focuses on the application of robust control laws to improve the controllability of the plasma current, a crucial parameter during the plasma heating and confinement processes. In particular, a variable structure control scheme based on sliding surfaces, namely, a sliding mode controller (SMC) is presented and applied to the plasma current control problem. In order to test the validity and goodness of the proposed controller, its behavior is compared to that of the traditional PID schemes applied in these systems, using the RZIp model for the Tokamak a Configuration Variable (TCV) reactor. The obtained results are very promising, leading to consider this controller as a strong candidate to enhance the performance of the PID-based controllers usually employed in this kind of systems.
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| 2. |
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| 3. |
- Bermejo-López, Aitor, et al.
(författare)
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Selective Synthesis of Imines by Photo-Oxidative Amine Cross-Condensation Catalyzed by PCN-222(Pd)
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:43, s. 14405-14415
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Tidskriftsartikel (refereegranskat)abstract
- Palladium-metalated PCN-222 enables the aerobic photo-oxidative cross-condensation of anilines with benzylic amines yielding a series of linear and cyclic imines. The reaction is very efficient under mild conditions, which allows the isolation of simple, yet elusive, intermediates such as 2-(benzylideneamino)-aniline and 2-(benzylideneamino)phenols. Recyclability studies show excellent activity and selectivity after five runs. The methodology was successfully applied for the synthesis of an antitumor agent (PMX-610).
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| 4. |
- Bermejo-López, Aitor, et al.
(författare)
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Selective Synthesis of Imines via Photooxidative AmineCross-Condensation Catalyzed by PCN-222(Pd)
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Palladium metallated PCN-222 enables the selective cross-condensation of anilines with benzylic aminesunder photooxidative conditions and at ambient temperature. The method affords a series of linear and cyclic Schiffbases. The mild conditions used in this catalytic system results in the isolation of resourceful intermediates such as 2-(benzylideneamino)aniline and 2-(benzylideneamino)phenols, which can be further modified.
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| 5. |
- Manel, Stéphanie, et al.
(författare)
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Long-Distance Benefits of Marine Reserves : Myth or Reality?
- 2019
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Ingår i: Trends in Ecology & Evolution. - : Elsevier BV. - 0169-5347 .- 1872-8383. ; 34:4, s. 342-354
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Forskningsöversikt (refereegranskat)abstract
- Long-distance (>40-km) dispersal from marine reserves is poorly documented; yet, it can provide essential benefits such as seeding fished areas or connecting marine reserves into networks. From a meta-analysis, we suggest that the spatial scale of marine connectivity is underestimated due to the limited geographic extent of sampling designs. We also found that the largest marine reserves (>1000 km(2)) are the most isolated. These findings have important implications for the assessment of evolutionary, ecological, and socio-economic long-distance benefits of marine reserves. We conclude that existing methods to infer dispersal should consider the up-to-date genomic advances and also expand the spatial scale of sampling designs. Incorporating long-distance connectivity in conservation planning will contribute to increase the benefits of marine reserve networks.
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| 6. |
- Manni, Giovanni Li, et al.
(författare)
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The OpenMolcas Web : A Community-Driven Approach to Advancing Computational Chemistry
- 2023
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Ingår i: Journal of Chemical Theory and Computation. - : American Chemical Society (ACS). - 1549-9618 .- 1549-9626. ; 19:20, s. 6933-6991
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Tidskriftsartikel (refereegranskat)abstract
- The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations.
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| 7. |
- Marco, Aitor, et al.
(författare)
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Sliding Surface Based Schemes for the Tokamak a Configuration Variable
- 2018
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Ingår i: 2018 WORLD AUTOMATION CONGRESS (WAC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781532377914 - 9781538662106 ; , s. 253-258
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Konferensbidrag (refereegranskat)abstract
- Fusion power may be seen as the energy of the future in the sense that it composes a potentially clean, cheap and unlimited power source that would reduce the worldwide dependency on non-renewable energies. Nevertheless, while nowadays the fusion reaction process itself has been achieved, significant net power has not yet been obtained, since the generated plasma needs to remain in particular pressure and temperature conditions. For this purpose, the plasma has to be confined. To do so, one of the solutions is to use a fusion reactor device that creates magnetic fields in a toroidal chamber, called Tokamak reactor. The main issue of Tokamak reactors is the presence of plasma instabilities, which provoke the fusion reaction decay and, in consequence, a reduction in the pulse duration. To maintain this pulse duration as long as possible, the use of robust and fast controllers is mandatory due to the unpredictability and the small time constant of the plasma behavior. In this context, this article focuses on improving the controllability of the plasma current, a relevant control variable, crucial during the plasma heating and confinement processes. In particular, two new robust control schemes based on sliding surfaces, namely, a Sliding Mode Controller (SMC) and a Supertwisting Controller (STC) are presented and applied to the plasma current control problem. In order to test the validity and goodness of the proposed controllers, their behavior is compared to that of the traditional PID schemes applied in these systems, using the RZIp model for the TCV (Tokamak a Configuration Variable) reactor. The obtained results are very promising, leading to consider these controllers as strong candidates to improve the performance of the PID-based controllers usually employed in this kind of systems.
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| 8. |
- Nana Koya, Alemayehu, et al.
(författare)
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Advances in ultrafast plasmonics
- 2023
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Ingår i: Applied Physics Reviews. - : American Institute of Physics (AIP). - 1931-9401. ; 10:2
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Forskningsöversikt (refereegranskat)abstract
- In the past 20 years, we have reached a broad understanding of many light-driven phenomena in nanoscale systems. The temporal dynamics of the excited states are instead quite challenging to explore, and, at the same time, crucial to study for understanding the origin of fundamental physical and chemical processes. In this review, we examine the current state and prospects of ultrafast phenomena driven by plasmons both from a fundamental and applied point of view. This research area is referred to as ultrafast plasmonics and represents an outstanding playground to tailor and control fast optical and electronic processes at the nanoscale, such as ultrafast optical switching, single photon emission, and strong coupling interactions to tailor photochemical reactions. Here, we provide an overview of the field and describe the methodologies to monitor and control nanoscale phenomena with plasmons at ultrafast timescales in terms of both modeling and experimental characterization. Various directions are showcased, among others recent advances in ultrafast plasmon-driven chemistry and multi-functional plasmonics, in which charge, spin, and lattice degrees of freedom are exploited to provide active control of the optical and electronic properties of nanoscale materials. As the focus shifts to the development of practical devices, such as all-optical transistors, we also emphasize new materials and applications in ultrafast plasmonics and highlight recent development in the relativistic realm. The latter is a promising research field with potential applications in fusion research or particle and light sources providing properties such as attosecond duration.
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