1,649 research outputs found

    On the changes in the physical properties of the ionized region around the Weigelt structures in Eta Carinae over the 5.54-yr spectroscopic cycle

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    We present HST/STIS observations and analysis of two prominent nebular structures around the central source of Eta Carinae, the knots C and D. The former is brighter than the latter for emission lines from intermediate or high ionization potential ions. The brightness of lines from intermediate and high ionization potential ions significantly decreases at phases around periastron. We do not see conspicuous changes in the brightness of lines from low ionization potential (<13.6 eV) that the total extinction towards the Weigelt structures is that the total extinction towards the Weigelt structures is AsubV =2/0. that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of 10exp6.9 cm-3 that does not significantly change throughout the orbital cycle. The electron temperature varies from 5500 K (around periastron) to 7200 K (around apastron). The relative changes in the brightness of He I lines are well reproduced by the variations in the electron temperature alone. We found that, at phases around periastron, the electron temperature seems to be higher for Weigelt C than that of D. The Weigelt structures are located close to the Homunculus equatorial plane, at a distance of about 1240 AU from the central source. From the analysis of proper motion and age, the Weigelt complex can be associated with the equatorial structure called the Butterfly Nebula surrounding the central binary system.Comment: 19 pages, 18 figure

    A Study of the Export Financing System in the Philippines

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    How much support is the Philippine government giving to its export sector by means of its financing schemes? Are the small and indirect exporters given preference or assistance? How supportive is the entire export financing system in the country to the attainment of an export-driven development strategy? These questions are the primary concern of this paper. Based on a survey sample of seven commercial banks, it examines the various components of the Philippine export financing system. A review of the Philippine trade policies and its export profiles is provided.financial market, financial economy, financial sector, export commodities, financial services

    Mullitización de mezclas de arcilla caolinítica e hidróxido de aluminio

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    Se calcinaron mezclas de arcilla caolinítica e hidróxido de aluminio, los ensayos se realizaron entre 900 y 1400°C, a distintos tiempos de calentamiento. Los compuestos obtenidos se estudiaron por técnicas de difracción de rayos X, dejándose establecido que se produce reacción entre la latexAl2O3latex Al_{2}O_{3} agregada y la latexSiO2latex SiO_{2} liberada, para formar mullita a temperaturas inferiores a 1400°C, cuando la mezcla se precalienta varias horas a temperaturas próximas a los 1000°C. Se confirmó el fenómeno de nucleación de mullita, por tratamientos térmicos similares en mezclas de ácido silícico e hidróxido de aluminio puros. Es de interés tecnológico lograr la transformación total a mullita, de mezclas arcilla alúmina, a temperaturas no mayores de 1400°C. Por esto, el presente trabajo tuvo por fin comprobar si la latexγAl2O3latex \gamma -Al_{2}O_{3} que se forma durante el calentamiento del latexAl(OH)3latex Al(OH)_{3} puede entrar en la reacción de mullitización del caolín, combinándose con la sílice remanente.Mixtures of kaolin clay and aluminium hydroxide were heated to temperatures between 900 and 1400°C for different periods. The heat treated samples were studied by X-ray diffraction techniques. It was clearly shown that the added latexAl2O3latex Al_{2}O_{3} reacts with the free latexSiO2latex SiO_{2} to form mullite at temperatures below 1400°C when the mixtures were preheated for several hours at temperatures approaching 1000°C. Through similar heating treatments in mixtures of silicic acid and pure aluminium hydroxide, the mullite nucleation phenomenon was confirmed. It is of technological interest to achieve the total transformation to mullite of the clay-alumina mixtures by heating to temperatures not exceeding 1400°C. It was the aim of the present investigation to observe the reaction between the latexγAl2O3latex \gamma-Al_{2}O_{3} form ed from latexAl(OH)3latex Al(OH)_{3} and the silica freed from the kaolin to form mullite

    Lo específico de la moral cristiana

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    Contribution of agronomic traits for sugar yield in sweet sorghum genotypes

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