| 1. |
- Aartsen, M. G., et al.
(författare)
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Very high-energy gamma-ray follow-up program using neutrino triggers from IceCube
- 2016
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- We describe and report the status of a neutrino-triggered program in IceCube that generates real-time alerts for gamma-ray follow-up observations by atmospheric-Cherenkov telescopes (MAGIC and VERITAS). While IceCube is capable of monitoring the whole sky continuously, high-energy gamma-ray telescopes have restricted fields of view and in general are unlikely to be observing a potential neutrino-flaring source at the time such neutrinos are recorded. The use of neutrino-triggered alerts thus aims at increasing the availability of simultaneous multi-messenger data during potential neutrino flaring activity, which can increase the discovery potential and constrain the phenomenological interpretation of the high-energy emission of selected source classes (e. g. blazars). The requirements of a fast and stable online analysis of potential neutrino signals and its operation are presented, along with first results of the program operating between 14 March 2012 and 31 December 2015.
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| 2. |
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| 3. |
- Rieth, M., et al.
(författare)
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A brief summary of the progress on the EFDA tungsten materials program
- 2013
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 442:1-3, s. S173-S180
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Tidskriftsartikel (refereegranskat)abstract
- The long-term objective of the European Fusion Development Agreement (EFDA) fusion materials programme is to develop structural and armor materials in combination with the necessary production and fabrication technologies for reactor concepts beyond the International Thermonuclear Experimental Reactor. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on "Materials Science and Modeling." This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on materials research, fabrication, joining, high heat flux testing, plasticity studies, modeling, and validation experiments.
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| 4. |
- Unsalan, Ozan, et al.
(författare)
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The Sariçiçek howardite fall in Turkey : Source crater of HED meteorites on Vesta and impact risk of Vestoids
- 2019
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Ingår i: Meteoritics and Planetary Science. - Hoboken : John Wiley & Sons. - 1086-9379 .- 1945-5100. ; 54:5, s. 953-1008
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Tidskriftsartikel (refereegranskat)abstract
- The Sariçiçek howardite meteorite shower consisting of 343 documented stones occurred on September 2, 2015 in Turkey and is the first documented howardite fall. Cosmogenic isotopes show that Sariçiçek experienced a complex cosmic‐ray exposure history, exposed during ~12–14 Ma in a regolith near the surface of a parent asteroid, and that an ~1 m sized meteoroid was launched by an impact 22 ± 2 Ma ago to Earth (as did one‐third of all HED meteorites). SIMS dating of zircon and baddeleyite yielded 4550.4 ± 2.5 Ma and 4553 ± 8.8 Ma crystallization ages for the basaltic magma clasts. The apatite U‐Pb age of 4525 ± 17 Ma, K‐Ar age of ~3.9 Ga, and the U,Th‐He ages of 1.8 ± 0.7 and 2.6 ± 0.3 Ga are interpreted to represent thermal metamorphic and impact‐related resetting ages, respectively. Petrographic; geochemical; and O‐, Cr‐, and Ti‐isotopic studies confirm that Sariçiçek belongs to the normal clan of HED meteorites. Petrographic observations and analysis of organic material indicate a small portion of carbonaceous chondrite material in the Sariçiçek regolith and organic contamination of the meteorite after a few days on soil. Video observations of the fall show an atmospheric entry at 17.3 ± 0.8 km s−1 from NW; fragmentations at 37, 33, 31, and 27 km altitude; and provide a pre‐atmospheric orbit that is the first dynamical link between the normal HED meteorite clan and the inner Main Belt. Spectral data indicate the similarity of Sariçiçek with the Vesta asteroid family (V‐class) spectra, a group of asteroids stretching to delivery resonances, which includes (4) Vesta. Dynamical modeling of meteoroid delivery to Earth shows that the complete disruption of a ~1 km sized Vesta family asteroid or a ~10 km sized impact crater on Vesta is required to provide sufficient meteoroids ≤4 m in size to account for the influx of meteorites from this HED clan. The 16.7 km diameter Antionia impact crater on Vesta was formed on terrain of the same age as given by the 4He retention age of Sariçiçek. Lunar scaling for crater production to crater counts of its ejecta blanket show it was formed ~22 Ma ago.
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| 5. |
- Galle, Bo, 1952, et al.
(författare)
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A multi-purpose, multi-rotor drone system for long-range and high-altitude volcanic gas plume measurements
- 2021
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 14:6, s. 4255-4277
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Tidskriftsartikel (refereegranskat)abstract
- A multi-rotor drone has been adapted for studies of volcanic gas plumes. This adaptation includes improved capacity for high-altitude and long-range, real-time SO2 concentration monitoring, long-range manual control, remotely activated bag sampling and plume speed measurement capability. The drone is capable of acting as a stable platform for various instrument configurations, including multi-component gas analysis system (MultiGAS) instruments for in situ measurements of SO2, H2S, and CO2 concentrations in the gas plume and portable differential optical absorption spectrometer (MobileDOAS) instruments for spectroscopic measurement of total SO2 emission rate, remotely controlled gas sampling in bags and sampling with gas denuders for posterior analysis on the ground of isotopic composition and halogens. The platform we present was field-tested during three campaigns in Papua New Guinea: in 2016 at Tavurvur, Bagana and Ulawun volcanoes, in 2018 at Tavurvur and Langila volcanoes and in 2019 at Tavurvur and Manam volcanoes, as well as in Mt. Etna in Italy in 2017. This paper describes the drone platform and the multiple payloads, the various measurement strategies and an algorithm to correct for different response times of MultiGAS sensors. Specifically, we emphasize the need for an adaptive flight path, together with live data transmission of a plume tracer (such as SO2 concentration) to the ground station, to ensure optimal plume interception when operating beyond the visual line of sight. We present results from a comprehensive plume characterization obtained during a field deployment at Manam volcano in May 2019. The Papua New Guinea region, and particularly Manam volcano, has not been extensively studied for volcanic gases due to its remote location, inaccessible summit region and high level of volcanic activity. We demonstrate that the combination of a multi-rotor drone with modular payloads is a versatile solution to obtain the flux and composition of volcanic plumes, even for the case of a highly active volcano with a high-altitude plume such as Manam. Drone-based measurements offer a valuable solution to volcano research and monitoring applications and provide an alternativespan idCombining double low line"page4256"/> and complementary method to ground-based and direct sampling of volcanic gases.
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| 6. |
- Hoffmann, Alice, 1983, et al.
(författare)
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Perception of Tyre Noise: Can Tyre Noise be Differentiated and Characterized by the Perception of a Listener Outside the Car?
- 2016
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Ingår i: Acta Acustica united with Acustica. - : Wissenschaftliche Verlagsgesellschaft mbH. - 1610-1928 .- 1861-9959. ; 102:6, s. 992-998
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Tidskriftsartikel (refereegranskat)abstract
- When constructing a tyre, it is of importance that improvements and planned changes are not only physically measurable, but that they also can be perceived by a listener. Tyre/road noise becomes a more important focus area, especially with the growing market of electric vehicles. In the design of tyre/road sound, there are three main aims: to reduce the overall sound level, to increase pleasantness and to do so still maintaining the carried information about e.g. driving conditions. To be able to do this, an understanding of how physical changes in a tyre are reflected in the perception of the same tyre is essential. In the present study, the aim is thus to determine if the rolling noise of a tyre can be both differentiated and characterized by its perceptual qualities. The focus is on the perception of the sound outside the car, perceived by, for example, a pedestrian. Listeners have judged different road tyre combinations and their perception in terms of their emotional responses (pleasantness, activation and stress) and their psychoacoustic responses (loudnes s, sharpness, roughness, and pitch). The results confirmed that rolling noise can be perceptually differentiated. Further, it is possible to differentiate between the effects of the street and the effects of the tyre on all emotional and most psychoacoustic parameters. The results suggest that changes to both road surfaces and tyres can affect both emotional and psychoacoustic perceptual qualities.
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| 7. |
- Defrere, D., et al.
(författare)
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L'-band AGPM vector vortex coronagraph's first light on LBTI/LMIRCam
- 2014
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Ingår i: Adaptive Optics Systems IV. - : SPIE. - 9780819496164
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Konferensbidrag (refereegranskat)abstract
- We present the first observations obtained with the L'-band AGPM vortex coronagraph recently installed on LBTI/LMIRCam. The AGPM (Annular Groove Phase Mask) is a vector vortex coronagraph made from diamond subwavelength gratings. It is designed to improve the sensitivity and dynamic range of high-resolution imaging at very small inner working angles, down to 0.09 arcseconds in the case of LBTI/LMIRCam in the L' band. During the first hours on sky, we observed the young A5V star HR8799 with the goal to demonstrate the AGPM performance and assess its relevance for the ongoing LBTI planet survey (LEECH). Preliminary analyses of the data reveal the four known planets clearly at high SNR and provide unprecedented sensitivity limits in the inner planetary system (down to the diffraction limit of 0.09 arcseconds).
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| 8. |
- Hoffmann, Markus, et al.
(författare)
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Skyrmions, Antiskyrmions and Bobbers : Novel particles in chiral magnets
- 2019
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Ingår i: The 10th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2019. - : META Conference. ; , s. 677-678
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Konferensbidrag (refereegranskat)abstract
- Chiral magnets are an emerging class of topological matter harbouring localized and topologically protected vortexlike magnetic textures called skyrmions, which are currently under intense scrutiny as a new entity for information storage and processing. Chirality in magnetism is introduced through the chiral symmetry breaking Dzyaloshinskii-Moriya interaction, which arizes through the spin-orbit interaction in magnets with structural bulk and interface inversion asymmetry. We have shown that chiral magnets cannot only host skyrmions but also antiskyrmions and chiral bobbers as localized magnetization particles. We present a multiscale approach relating the electronic structure to an atomistic spin-lattice model and further to micromagnetic models by means of densityfunctional calculations, derive practical criteria for their occurrence and coexistence with skyrmions and minimizing the energy on a mesoscopic scale applying varying spinrelaxation methods. We conjecture on possible materials for antiskyrmions and give experimental evidence for bobbers. The technology potential of having two distinctly different stable particles will be discussed.
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| 9. |
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| 10. |
- Hoffmann, Henry, et al.
(författare)
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Self-aware computing in the Angstrom processor
- 2012
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Ingår i: Proceedings of the 49th Annual Design Automation Conference. - New York, NY, USA : ACM. - 9781450311991 ; , s. 259-264
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Konferensbidrag (refereegranskat)abstract
- Addressing the challenges of extreme scale computing re- quires holistic design of new programming models and sys- tems that support those models. This paper discusses the Angstrom processor, which is designed to support a new Self-aware Computing (SEEC) model. In SEEC, applications explicitly state goals, while other systems components provide actions that the SEEC runtime system can use to meet those goals. Angstrom supports this model by ex- posing sensors and adaptations that traditionally would be managed independently by hardware. This exposure allows SEEC to coordinate hardware actions with actions specified by other parts of the system, and allows the SEEC runtime system to meet application goals while reducing costs (e.g., power consumption).
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