| 1. |
- Marganiec, J., et al.
(författare)
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Coulomb breakup of 17Ne from the viewpoint of nuclear astrophysics
- 2012
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Ingår i: Proceedings of Science. - Proceedings of Science : Sissa. - 1824-8039.
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Konferensbidrag (refereegranskat)abstract
- By the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p,γ)17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section sCoul has been determined, which then will be converted into a photo-absorption cross section sphoto, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.
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| 2. |
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| 3. |
- Kalenskii, S.V., et al.
(författare)
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Class I methanol masers in low-mass star formation regions
- 2012
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Ingår i: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 8:5287, s. 161-165
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Konferensbidrag (refereegranskat)abstract
- Four Class I maser sources were detected at 44, 84, and 95 GHz toward chemically rich outflows in the regions of low-mass star formation NGC 1333I4A, NGC 1333I2A, HH25, and L1157. One more maser was found at 36 GHz toward a similar outflow, NGC 2023. Flux densities of the newly detected masers are no more than 18 Jy, being much lower than those of strong masers in regions of high-mass star formation. The brightness temperatures of the strongest peaks in NGC 1333I4A, HH25, and L1157 at 44 GHz are higher than 2000 K, whereas that of the peak in NGC 1333I2A is only 176 K. However, a rotational diagram analysis showed that the latter source is also a maser. The main properties of the newly detected masers are similar to those of Class I methanol masers in regions of massive star formation. The former masers are likely to be an extension of the latter maser population toward low luminosities of both the masers and the corresponding YSOs.
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| 4. |
- Andreasson, Martin, et al.
(författare)
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Distributed integral action : stability analysis and frequency control of power systems
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 2077-2083
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes distributed proportional-integral controllers. We prove that integral action can be successfully applied to consensus algorithms, where attenuation of static disturbances is achieved. These control algorithms are applied to decentralized frequency control of electrical power systems. We show that the proposed algorithm can attenuate step disturbances of power loads. We provide simulations of the proposed control algorithm on the IEEE 30 bus test system that demonstrate its efficiency.
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| 5. |
- Andreasson, Martin, 1987-, et al.
(författare)
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Undamped Nonlinear Consensus Using Integral Lyapunov Functions
- 2012
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Ingår i: 2012 American Control Conference (ACC). - : IEEE Computer Society. - 9781457710964 ; , s. 6644-6649
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes a class of nonlinear consensus algorithms where the input of an agent can be decoupled into a product of a gain function of the agents own state, and a sum of interaction functions of the relative states of its neighbors. We prove the stability of the protocol for both single and double integrator dynamics using novel Lyapunov functions, and provide explicit formulas for the consensus points. The results are demonstrated through simulations of a realistic example within the framework of our proposed consensus algorithm.
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| 6. |
- Aragues, R., et al.
(författare)
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Distributed algebraic connectivity estimation for adaptive event-triggered consensus
- 2012
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Ingår i: American Control Conference (ACC), 2012. - : IEEE. - 9781457710957 ; , s. 32-37
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Konferensbidrag (refereegranskat)abstract
- In several multi agent control problems, the convergence properties and speed of the system depend on the algebraic connectivity of the graph. We discuss a particular event-triggered consensus scenario, and show that the availability of an estimate of the algebraic connectivity could be used for adapting the behavior of the average consensus algorithm. We present a novel distributed algorithm for estimating the algebraic connectivity, that relies on the distributed computation of the powers of matrices. We provide proofs of convergence, convergence rate, and upper and lower bounds at each iteration of the estimated algebraic connectivity.
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| 7. |
- Bismarck, A., et al.
(författare)
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Multifunctional epoxy resin for structural supercapacitors
- 2012
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Ingår i: 15th European Conference on Composite Materials: Composites at Venice, ECCM 2012; Venice; Italy; 24 June 2012 through 28 June 2012. - 9788888785332
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Konferensbidrag (refereegranskat)abstract
- Polymer-based electrolytes based on commercially available epoxy resins were prepared through the addition of a liquid electrolyte, a solution of a lithium salt in an ionic liquid. The polymer monoliths were characterized using impedance spectroscopy, 3-point bending test, scanning electron microscopy (SEM) and nitrogen adsorption (BET). The balance of ionic conductivity and flexural modulus is crucially dependent on the relative proportions of epoxy resin to electrolyte. Also the effect of the liquid electrolyte on curing kinetics and processing was assessed by complex viscosity measurements and differential scanning calorimetry (DSC). Only one out of the three resins investigated exhibited a significant acceleration effect.
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| 8. |
- Brethouwer, Gert, et al.
(författare)
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Turbulence, instabilities and heat transfer in rotating channel flow simulations
- 2012
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Ingår i: Proceedings of the International Symposium on Turbulence, Heat and Mass Transfer. - : Begell House Inc.. ; , s. 703-706
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Konferensbidrag (refereegranskat)abstract
- Direct numerical simulations of fully developed turbulent channel flow rotating about the spanwise direction are performed over a wide range of Reynolds numbers and rotation speeds. A scalar is also included to examine rotation effects on heat transfer. The Reynolds number based on the bulk mean velocity is up to 30 000, which is higher than in previous studies of rotating channel flow. The flow partly or completely relaminarizes on the stable channel side at sufficiently high rotation speeds, leading to distinct turbulent-laminar patterns in certain cases. Strong cyclic bursts of turbulence are observed at higher rotation speeds and sufficiently high Reynolds numbers. Further analysis showed that the burst are caused by plane spanwise waves with a rapidly growing amplitude, which become unstable after some time and break down into intense turbulence. Rotation strongly affects the direction of the turbulent scalar flux and significantly reduces the turbulent Prandtl number.
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| 9. |
- Guo, Meng, et al.
(författare)
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Distributed real-time fault detection and isolation for cooperative multi-agent systems
- 2012
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Ingår i: 2012 American Control Conference (ACC). - : IEEE Computer Society. - 9781457710957 ; , s. 5270-5275
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose a distributed real-time fault detection, isolation and mitigation framework for multiagent systems performing cooperative tasks. Various system models and detection schemes with respect to communication and sensing are considered. Two communication protocols for fault detection are introduced first and proved to be effective. Then a scheme based on limited relative state measurements is developed. Furthermore, we propose fault isolation and mitigation steps to guarantee the accomplishment of a global objective. All schemes are distributed in the sense that at each step of the fault detection, isolation and mitigation every agent only uses locally available information. One key feature of the framework is the significant reduction of required computational resource when compared with the fault detection and isolation schemes based on unknown input observers. Later we show that the proposed framework can be applied to the consensus and other cooperative formation problems. Several computer simulations are presented to demonstrate the efficiency of the framework.
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| 10. |
- Krasznahorkay, A., et al.
(författare)
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Neutron-skin thickness from the study of the anti-analog giant dipole resonance
- 2012
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Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. - 9780735411036 ; 1491, s. 190-197
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Konferensbidrag (refereegranskat)abstract
- The γ-decay of the anti-analog of the giant dipole resonance (AGDR) to the isobaric analog state has been measured following the p( 124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent relativistic random-phase approximation (RPA) and turned out to be very sensitive to the neutronskin thickness (ΔRpn). By comparing the theoretical results with the measured one, the ΔRpn value for 124Sn was deduced to be 0.21 ± 0.07 fm, which agrees well with the previous results. The present method offers new possibilities for measuring the neutron-skin thicknesses of very exotic isotopes.
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