| 1. |
- Annala, E., et al.
(författare)
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Constraining the properties of neutron-star matter with observations
- 2019
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Ingår i: Memorie della Societa Astronomica Italiana - Journal of the Italian Astronomical Society. - : Societa Astronomica Italiana. ; , s. 81-86
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Konferensbidrag (refereegranskat)abstract
- In this conference-proceedings contribution, we review recent advances in placing model-independent constraints on the properties of cold and dense QCD matter inside neutron stars. In addition to introducing new bounds for the Equation of State, we explain how these results may be used to make robust statements about the physical phase of strongly interacting matter in the centers of neutron stars of different masses. Our findings indicate that the existence of quark-matter cores inside massive neutron stars appears to be a very common feature of the allowed Equations of State, and should not be considered an exotic or unlikely scenario.
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| 2. |
- Annala, E., et al.
(författare)
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Evidence for quark-matter cores in massive neutron stars
- 2020
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Ingår i: Nature Physics. - : Nature Research. - 1745-2473 .- 1745-2481. ; 16:9, s. 907-910
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Tidskriftsartikel (refereegranskat)abstract
- The theory governing the strong nuclear force-quantum chromodynamics-predicts that at sufficiently high energy densities, hadronic nuclear matter undergoes a deconfinement transition to a new phase of quarks and gluons(1). Although this has been observed in ultrarelativistic heavy-ion collisions(2,3), it is currently an open question whether quark matter exists inside neutron stars(4). By combining astrophysical observations and theoretical ab initio calculations in a model-independent way, we find that the inferred properties of matter in the cores of neutron stars with mass corresponding to 1.4 solar masses (M-circle dot) are compatible with nuclear model calculations. However, the matter in the interior of maximally massive stable neutron stars exhibits characteristics of the deconfined phase, which we interpret as evidence for the presence of quark-matter cores. For the heaviest reliably observed neutron stars(5,6) with mass M approximate to 2M(circle dot), the presence of quark matter is found to be linked to the behaviour of the speed of sound c(s) in strongly interacting matter. If the conformal bound cs2 <= 1/3 (ref. (7)) is not strongly violated, massive neutron stars are predicted to have sizable quark-matter cores. This finding has important implications for the phenomenology of neutron stars and affects the dynamics of neutron star mergers with at least one sufficiently massive participant.
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| 3. |
- Simell, P., et al.
(författare)
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Provisional protocol for the sampling and anlaysis of tar and particulates in the gas from large-scale biomass gasifiers. Version 1998
- 2000
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Ingår i: Biomass and Bioenergy. - 0961-9534 .- 1873-2909. ; 18:1, s. 19-38
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents tar sampling protocols for pressurised and atmospheric large scale gasification processes. Methods for constructing sampling lines either to on-line analysers or into sampling systems are described. The tar sampling system consists of a heated probe, a particulate filter and a series of impinger bottles. Dichloromethane is used as the tar absorbing solvent. The solvent containing bottles are placed in a cold bath so that gradual cooling of the sampled gas from about 0 degrees C to the final temperature -79 degrees C takes place in them. Recommendations for suitable sampling gas flow rates and gas temperatures are given. Tar characterisation methods based on different garvimetric measurements and GC analysis are described.
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| 4. |
- Somppi, J.L., et al.
(författare)
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Ultrafine ash particle formation during waste sludge incineration in fluidized bed reactors
- 1998
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Ingår i: Combustion Science and Technology. - : Informa UK Limited. - 0010-2202 .- 1563-521X. ; 134, s. 433-455
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Tidskriftsartikel (refereegranskat)abstract
- Ash formation during the bubbling fluidized bed (BFB) combustion of bark and pulp mill sludge has been studied on an industrial and bench scale. During co-firing in an industrial BFB a submicron fly ash mode was formed via condensation of volatilized K, Na, S and Cl species at 0.05-0.3 μm. The submicron mass mode below 0.3 μm made up 2.2-5.0% of the fly ash, while the share of the supermicron mass fraction was 93.6-97.2%. Elements depleted in the ultrafine ash were Ca, Si, Al, Mg, Fe, Mn, P and Ti. The bench-scale test showed that the ultrafine particle concentration was increased by a higher bed temperature and decreased due to sludge moisture. As, Cd, Pb and Rb were enriched in the ultrafine ash on a bench scale, while Ba, Co, Sr and V were depleted. Cu and Zn were enriched in the ultrafine ash during the combustion of dried sludge, but not when wet sludge was fired. Micron-size ash particles composed of non-volatile species, Ca, Si, Mg, Al, P and Mn, adhered to the bed sand, presumably by surface forces, and sintering densified the ash layer. © 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint.
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| 5. |
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| 6. |
- Watts, Anna L., et al.
(författare)
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Dense matter with eXTP
- 2019
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Ingår i: Science China Physics, Mechanics & Astronomy. - : Science Press. - 1674-7348 .- 1869-1927. ; 62:2
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Forskningsöversikt (refereegranskat)abstract
- In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry (eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is expected to be launched in the mid 2020s.
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