Simulated X-ray emission for a runaway model of Kepler's supernova remnant

Fil:Velázquez, P.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Vigh, C.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Reynoso, E.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Gómez, D.O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

The photochemistry of penicillamine disulphide and related compounds

SIGLEAvailable from British Library Document Supply Centre- DSC:D43411/82 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Hu 1-2: A metal-poor bipolar planetary nebula with fast collimated outflows

© 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. We present narrow-band optical and near-IR imaging and optical long-slit spectroscopic observations of Hu 1-2, a Galactic planetary nebula (PN) with a pair of [NII]-bright, fast-moving (>340 km s-1) bipolar knots. Intermediate-dispersion spectra are used to derive physical conditions and abundances across the nebula, and high-dispersion spectra to study the spatiokinematical structure. Generally, Hu 1-2 has high He/H (˜0.14) and N/O ratios (˜0.9), typical of Type I PNe. On the other hand, its abundances of O, Ne, S, and Ar are low as compared with the average abundances of Galactic bulge and disc PNe. The position-velocity maps can be generally described as an hour-glass shaped nebula with bipolar expansion, although the morphology and kinematics of the innermost regions cannot be satisfactorily explained with a simple, tilted equatorial torus. The spatio-kinematical study confines the inclination angle of its major axis to be within 10° of the plane of sky. As in the irradiated bow-shocks of IC 4634 and NGC 7009, there is a clear stratification in the emission peaks of [O III], Ha, and [N II] in the north-west (NW) knot of Hu 1-2. Fast collimated outflows in PNe exhibit higher excitation than other low-ionization structures. This is particularly the case for the bipolar knots of Hu 1-2, with He II emission levels above those of collimated outflows in other Galactic PNe. The excitation of the knots in Hu 1-2 is consistent with the combined effects of shocks and UV radiation from the central star. The mechanical energy and luminosity of the knots are similar to those observed in the PNe known to harbour a post-common envelope (post-CE) close binary central star

Simulated X-ray emission for a runaway model of Kepler's supernova remnant

We present two-dimensional numerical simulations of a model for Kepler's supernova remnant (SNR) carried out with the YGUAZÚ-A code. Following previous studies, we have assumed that the peculiar shape of this young remnant arises as a consequence of the interaction of the SNR blast wave with the bow shock formed by the wind of its high velocity progenitor. Furthermore, from our numerical results we have obtained synthetic X-ray emission maps, which can be directly compared with recent and previous observations of this SNR. Our models show that a nice fit with respect to the X-ray morphology and luminosity is obtained for a SN progenitor with mass-loss rate of 5 × 10-5 M⊙yr-1, an ambient medium density of 10 -2cm-3, an initial explosion energy of 8 × 10 50 ergs, and a total ejected mass within 1.4-2.5 M⊙. In our simulations, parameters typical of a young population progenitor have not been considered. This model also predicts a ∼0.3% yearly decrease in the total X-ray luminosity, which is consistent with observed values. The parameters employed in our runs correspond to a Type la supernova. Based on our simulations, we find that the expansion rate increases after the SNR blast wave overruns the bow shock, and we discuss whether this can explain the observed difference between the expansion rates measured from sequences of radio and X-ray images. © 2006. The American Astronomical Society. All rights reserved.Fil:Velázquez, P.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Vigh, C.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Reynoso, E.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Gómez, D.O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

PRODUÇÃO E AVALIAÇÃO DE BRIQUETES DE FINOS DE CARVÃO VEGETAL COMPACTADOS COM RESÍDUO CELULÓSICO PROVENIENTE DA INDÚSTRIA DE PAPEL E CELULOSE1

RESUMO Este trabalho teve por objetivo avaliar briquetes produzidos a partir de finos de carvão vegetal compactados com resíduo celulósico gerado na decantação dos efluentes da indústria de papel e celulose. Foram realizados os seguintes tratamentos: briquetes produzidos com fino de carvão vegetal e resíduo celulósico nas proporções de 25% (T1), 30% (T2), 35% (T3), 40% (T4) e 45% (T5) e briquetes produzidos com finos de carvão vegetal com 10% de amido e resíduo celulósico nas proporções de 0% (T6), 5% (T7), 10% (T8), 15% (T9), 20% (T10) e 25% (T11). A caracterização dos briquetes foi realizada por meio de ensaios de análise química imediata, determinação do poder calorífico superior, densidade aparente e avaliação da resistência mecânica após a secagem dos briquetes em estufa ou ao ar livre. Observou-se que os briquetes com resíduo celulósico e amido em sua composição apresentaram maior densidade e resistência mecânica à compressão, concluindo-se, assim, que a presença do amido favoreceu a compactação e estabilidade dos briquetes. Observou-se, também, que o processo de secagem em estufa prejudicou a qualidade dos briquetes, de modo que a secagem ao ar livre forneceu briquetes mais resistentes e estáveis