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Blackwell Publishing Ltd 2009 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.398 No.4
<P>ABSTRACT</P><P>The masses of the central supermassive black holes (BHs) and the Eddington ratios for a sample of 65 young radio galaxies [27 gigahertz-peaked spectrum (GPS) and 38 compact steep-spectrum (CSS) sources] are estimated by various methods. We find that the average BH mass of these young radio galaxies is 〈log <I>M</I><SUB>BH</SUB>〉≃ 8.3, which is less than that of radio loud quasi-stellar objects (QSOs) and low-redshift radio galaxies (〈log <I>M</I><SUB>BH</SUB>〉≃ 9.0). The CSS/GPS sources have relatively high Eddington ratios with average ratio 〈log <I>L</I><SUB>bol</SUB>/<I>L</I><SUB>Edd</SUB>〉=−0.56, which are similar to those of narrow-line Seyfert 1 galaxies (NLS1s). It suggests that the CSS/GPS sources may not only be in the early stage of radio activities, but also in the early stage of their accretion activities.</P><P>We find that the young radio galaxies as a class deviate systematically from the <I>M</I><SUB>BH</SUB>–σ<SUB>*</SUB> relation defined by nearby inactive galaxies, when using σ<SUB>[O <SMALL>III</SMALL></SUB> as a surrogate for the stellar velocity dispersion σ<SUB>*</SUB>. There is no significant correlation between the deviation of the [O <SMALL>III</SMALL>] emission line width, Δσ≡σ<SUB>[O <SMALL>III</SMALL>]</SUB>−σ<SUB>[pred]</SUB> and the jet/accretion power, where σ<SUB>[pred]</SUB> are calculated from the Tremaine et al. relation using the estimated BH masses. However, we find that the deviation Δσ in young radio galaxies is well correlated with the Eddington ratio, and this correlation is found to be similar to that of radio quiet active galactic nuclei (AGN) (QSOs/NLS1s) where the radio jet is absent or weak. We suggest that the accretion activities may still play an important role in shaping the kinematics of [O <SMALL>III</SMALL>] narrow line in these young radio galaxies.</P>
Thermal degradation and flammability behavior of fire-retarded wood flour/polypropylene composites
Sun, Lichao,Wu, Qinglin,Xie, Yanjun,Cueto, Rafael,Lee, Sunyoung,Wang, Qingwen Technomic Publising 2016 Journal of Fire Sciences Vol.34 No.3
<P>Magnesium hydroxide, expandable graphite, and ammonium polyphosphate were used to enhance the thermal stability and fire retardant properties on wood flour/polypropylene composites. The thermal decompositions and flammability properties were investigated using modulated thermogravimetric analysis and cone calorimeter, and the activation energy of each decomposition process was also determined by modulated thermogravimetric analysis. The results showed that both expandable graphite and ammonium polyphosphate promoted thermal degradation of wood flour and char formulation, and magnesium hydroxide did not influence on the wood flour decomposition. Unlike in nitrogen atmosphere, magnesium hydroxide and ammonium polyphosphate increased the peak temperature of wood flour thermal degradation and diminished the decomposition peaks of polypropylene in air atmosphere. Cone calorimeter results showed that expandable graphite greatly reduced the heat and smoke release. A general activation energy range of 187-226kJmol(-1) (in nitrogen), 165-206kJmol(-1) (in air) at wood flour degradation stage, 237-262kJmol(-1) (in nitrogen), and 185-269kJmol(-1) (in air) at polypropylene degradation stage were proposed for wood flour/polypropylene composite with and without fire retardants.</P>