| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
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| 3. |
- 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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| 4. |
- Jones, Geraint H., et al.
(författare)
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The Comet Interceptor Mission
- 2024
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Ingår i: Space Science Reviews. - : Springer Nature. - 0038-6308 .- 1572-9672. ; 220:1
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum Δ V capability of 600 ms − 1 . Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule.
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| 7. |
- Ebenhard, Torbjörn, et al.
(författare)
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Environmental effects of brushwood harvesting for bioenergy
- 2017
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 85-98
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Tidskriftsartikel (refereegranskat)abstract
- Sweden aims to increase the proportion of renewable energy sources, ultimately to be able to phase out fossil fuels. To achieve this, new energy sources need to be explored. In this multi-disciplinary article, we examine the technical, economical, ecological and legal possibilities to commercially and sustainably harvest brushwood for bioenergy, while simultaneously gaining positive environmental effects, both for biological diversity, the cultural heritage, and the climate. The Swedish open landscape is becoming covered with secondary brushwood regrowth through natural succession, except where it is kept open. Brushwood is spreading along roads, railway lines, edge zones, in power line corridors, abandoned semi-natural grasslands, nature reserves, and in marginal land in urban areas. Such brushwood consists of saplings, bushes and young trees of a range of deciduous plant species, e.g. birch, aspen, alder and goat willow, sometimes mixed with conifers, often forming dense thickets. Such secondary brushwood regrowth could be systematically utilised as a new source of renewable bioenergy. Commercial brushwood harvesting in Sweden may contribute 26 PJ of energy annually, which may be a small but significant contribution, considering the favourable energy ratio (E-r = 28), indicating that large emission reductions can be achieved, if fossil fuels are replaced. Growing brushwood does not require fertilizers or pesticides, soil tillage or crop management, and it does not compete with any other potential land use. Many brushwood habitats are already being managed to clear brushwood, for other purposes, minimizing the added harvesting cost. Apart from providing bioenergy, it has also been suggested that brushwood harvesting would benefit biological diversity. A large number of nationally redlisted species are dependent on the active management of open habitats, including semi-natural grasslands, and man-made habitats such as road verges and power line corridors. Our literature review shows that brushwood harvesting could benefit both biological diversity and the cultural heritage, and contribute to the management of the open cultural landscape. There are however certain limitations. Brushwood harvesting would favour a certain set of species, including many redlisted, but it may also threaten another set of species, especially species associated with early successional stages of forest regeneration, as well as forest edge species, depending on how and where it is applied. Harvesting may be affected by legislation imposing limitations regarding habitats of particular importance for biodiversity. The environmental and legal constraints would probably reduce the profitability of brushwood harvesting in certain areas, as well as the annual production of bioenergy.
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| 9. |
- Rahman, Hamidur, et al.
(författare)
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Falling Angel - a Wrist Worn Fall Detection System Using K-NN Algorithm
- 2016
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Konferensbidrag (refereegranskat)abstract
- A wrist worn fall detection system has been developed where the accelerometer data from an angel sensor is analyzed by a two-layered algorithm in an android phone. Here, the first layer uses a threshold to find potential falls and if the thresholds are met, then in the second layer a machine learning i.e., k-Nearest Neighbor (k-NN) algorithm analyses the data to differentiate it from Activities of Daily Living (ADL) in order to filter out false positives. The final result of this project using the k-NN algorithm provides a classification sensitivity of 96.4%. Here, the acquired sensitivity is 88.1% for the fall detection and the specificity for ADL is 98.1%.
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| 10. |
- Franzén, Sara, et al.
(författare)
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Compositional tuning of gas-phase synthesized Pd–Cu nanoparticles
- 2023
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Ingår i: Nanoscale Advances. - 2516-0230. ; 5:22, s. 6069-6077
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Tidskriftsartikel (refereegranskat)abstract
- Bimetallic nanoparticles have gained significant attention in catalysis as potential alternatives to expensive catalysts based on noble metals. In this study, we investigate the compositional tuning of Pd–Cu bimetallic nanoparticles using a physical synthesis method called spark ablation. By utilizing pure and alloyed electrodes in different configurations, we demonstrate the ability to tailor the chemical composition of nanoparticles within the range of approximately 80 : 20 at% to 40 : 60 at% (Pd : Cu), measured using X-ray fluorescence (XRF) and transmission electron microscopy energy dispersive X-ray spectroscopy (TEM-EDXS). Time-resolved XRF measurements revealed a shift in composition throughout the ablation process, potentially influenced by material transfer between electrodes. Powder X-ray diffraction confirmed the predominantly fcc phase of the nanoparticles while high-resolution TEM and scanning TEM-EDXS confirmed the mixing of Pd and Cu within individual nanoparticles. X-ray photoelectron and absorption spectroscopy were used to analyze the outermost atomic layers of the nanoparticles, which is highly important for catalytic applications. Such comprehensive analyses offer insights into the formation and structure of bimetallic nanoparticles and pave the way for the development of efficient and affordable catalysts for various applications.
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