| 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. |
- Wiedorn, Max O., et al.
(författare)
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Megahertz serial crystallography
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The new European X-ray Free-Electron Laser is the first X-ray free-electron laser capable of delivering X-ray pulses with a megahertz inter-pulse spacing, more than four orders of magnitude higher than previously possible. However, to date, it has been unclear whether it would indeed be possible to measure high-quality diffraction data at megahertz pulse repetition rates. Here, we show that high-quality structures can indeed be obtained using currently available operating conditions at the European XFEL. We present two complete data sets, one from the well-known model system lysozyme and the other from a so far unknown complex of a beta-lactamase from K. pneumoniae involved in antibiotic resistance. This result opens up megahertz serial femtosecond crystallography (SFX) as a tool for reliable structure determination, substrate screening and the efficient measurement of the evolution and dynamics of molecular structures using megahertz repetition rate pulses available at this new class of X-ray laser source.
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| 6. |
- Clack, Christopher T. M., et al.
(författare)
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Evaluation of a proposal for reliable low-cost grid power with 100% wind, water, and solar
- 2017
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 114:26, s. 6722-6727
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Tidskriftsartikel (refereegranskat)abstract
- A number of analyses, meta-analyses, and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration, the National Renewable Energy Laboratory, and the International Energy Agency, have concluded that deployment of a diverse portfolio of clean energy technologies makes a transition to a low-carbon-emission energy system both more feasible and less costly than other pathways. In contrast, Jacobson et al. [Jacobson MZ, Delucchi MA, Cameron MA, Frew BA (2015) Proc Natl Acad Sci USA 112(49): 15060-15065] argue that it is feasible to provide "low-cost solutions to the grid reliability problem with 100% penetration of WWS [wind, water and solar power] across all energy sectors in the continental United States between 2050 and 2055", with only electricity and hydrogen as energy carriers. In this paper, we evaluate that study and find significant shortcomings in the analysis. In particular, we point out that this work used invalid modeling tools, contained modeling errors, and made implausible and inadequately supported assumptions. Policy makers should treat with caution any visions of a rapid, reliable, and low-cost transition to entire energy systems that relies almost exclusively on wind, solar, and hydroelectric power.
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| 7. |
- Camerlenghi, A., et al.
(författare)
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Good reasons for IODP to address submarine geohazards : (with focus on the Mediterranean)
- 2009
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Konferensbidrag (refereegranskat)abstract
- Following a number of international workshop held in the last few years, this documents synthesise the reasons why future scientific ocean drilling should prioritize geohazards among the scientific objectives. In essence the reasons are the societal relevance, the opportunity to deepen the knowledge of basic geological processes in basin evolution, and the opportunity for technological development. A focus in placed on the Mediterranean Basin because of its high vulnerability to submarine geohazards, and to the known widespread occurrence (in the present and in the recent geological record) of geohazards. Among geohazards of the Mediterranean, a focus is placed on the submarine landslides because of their potential to affect seabed structure and the coastline via the tsunamis they can generate. A list of technological needs and a list of the international workshops is added for reference at the end of the document.
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| 8. |
- Welsch, Manuel, et al.
(författare)
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Adding value with CLEWS - Modelling the energy system and its interdependencies for Mauritius
- 2014
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 113, s. 1434-1445
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Tidskriftsartikel (refereegranskat)abstract
- Climate, Energy, Water and Land-use Systems (CLEWS) are closely integrated. Yet, most related decision and policy making occurs in disparate institutional entities, informed by relatively disconnected assessments of the individual resource systems. This paper presents the added value of an integrated analytical assessment approach. In doing so, it explicitly values various interdependencies and interactions between CLEWS primarily from an energy sector perspective. The island state of Mauritius was identified as a useful case study given its diverse climate, its increasing water stresses, and its policy focus on reshaping agricultural land-use and reducing fossil fuel imports. Several scenarios to 2030 were defined and analysed to demonstrate the tensions around the CLEWS nexus. Results from an assessment of the energy system with no modelled interlinkages to land-use, energy and water systems are first presented. Then, these are compared to those from an integrated CLEWS assessment. This serves to highlight important dynamics that would have been overlooked without such a systems approach. As an example, the added value of this approach is clearly demonstrated when rainfall reductions are taken into account, and where future land-use changes might occur.
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- Welsch, Manuel, et al.
(författare)
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Smart and Just Grids for sub-Saharan Africa : Exploring options
- 2013
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 20, s. 336-352
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Tidskriftsartikel (refereegranskat)abstract
- In 2009, an estimated 585 million people had no access to electricity services in sub-Saharan Africa. Unlike many other regions of the world, under current assumptions, that figure is expected to rise significantly to about 652 million by 2030-an unsustainable and unacceptable situation. Knowing of the intrinsic linkages between access to energy services and development, national governments and regional organisations have identified the urgent need for accelerated electrification rates. Some of the established and emerging concepts, systems and technologies grouped under the term 'Smart Grids' may offer an important contribution to achieving universal access to electricity. We argue that these Smart Grid advances may enable sub-Saharan African countries to leapfrog elements of traditional power systems and accelerate and improve electrification efforts. We introduce the notion of Just Grids to reflect the need for power systems to contribute towards equitable and inclusive economic and social development without marginalising the poor. The paper reviews the literature, and identifies specific options that could be implemented in sub-Saharan Africa. After selecting criteria that focus on potential impact as well as requirements for their implementation, a qualitative first-pass assessment of the potential of these options is made. This paper provides support for policy development, and suggests areas for further, more detailed research.
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