The last Gift of BeppoSAX: PDS Observations of the two Blazars 1ES 0507-040 and PKS 1229-021

Towards the end of the BeppoSAX mission, the only operated Narrow Field Instrument was the PDS, which covers the energy range 13-300 keV. Two blazars, 1ES 0507-040 (z=0.304) and PKS 1229-021 (z= 1.045), suitably located in the sky for BeppoSAX pointing, were observed for about 2 days each in Spring 2002 with the PDS and detected up to 50 keV. 1ES0507-040 had been already observed by the BeppoSAX NFIs at an earlier epoch for a much shorter time. We have re-analysed those data as well, and identified a possible contamination problem in the PDS spectrum. We present our recent PDS data on both sources, combined with the previous BeppoSAX data and with non-simultaneous observations at other frequencies. The derived Spectral Energy Distributions allow us to discuss the origin of the high energy component.Comment: 4 pages, 6 figures, poster presented at the symposium: The Restless High-Energy Universe, Amsterdam, May 200

Quantitative characterization of the x-ray imaging capability of rotating modulation collimators with laser light

We developed a method for making quantitative characterizations of bi-grid rotating modulation collimators (RMC ’s) that are used in a Fourier transform x-ray imager. With appropriate choices of the collimator spacings, this technique can be implemented with a beam-expanded He -Ne laser to simulate the plane wave produced by a point source at infinity even though the RMC ’s are diffraction limited at the He -Ne wavelength of 632.8 nm. The expanded beam passes through the grid pairs at a small angle with respect to their axis of rotation, and the modulated transmission through the grids as the RMC ’s rotate is detected with a photomultiplier tube. In addition to providing a quantitative characterization of the RMC ’s, the method also produces a measured point response function and provides an end-to-end check of the imaging system. We applied our method to the RMC ’s on the high-energy imaging device (HEIDI) balloon payload in its preflight configuration. We computed the harmonic ratios of the modulation time profile from the laser measurements and compared them with theoretical calculations, including the diffraction effects on irregular grids. Our results indicate the 25-in. (64-cm) x-ray imaging optics on HEIDI are capable of achieving images near the theoretical limit and are not seriously compromised by imperfections in the grids

Transesterificação de óleos vegetais para fins combustíveis.

Amostras de óleos de soja, algodão, colza, girassol e amendoim, depois de refinação alcalina, foram submetidos à transesterificações com metanol e etanol. Observou-se que enquanto as reações com metanol ou etanol anidro p.a. se processam facilmente com altos rendimentos e recuperação quase total do glicerol, as reações com etanol anidro comercial são mais complicadas não havendo separação do glicerol, ocorrendo grandes perdas. Foi desenvolvido, na EMBRAPA-CTAA, um processo que permite a obtenção dos ésteres etílicos, com etanol anidro comercial com conversão quase completa dos triglicerídios e separação do glicerol por adição de uma certa quantidade de glicerol.bitstream/item/118260/1/transesterificacao-de-oleos-vegetais.pd

Transesterificação de óleo de soja com diversos catalisadores alcalinos.

Amostras de óleo de soja neutralizado e seco foram transesterificadas com etanol comercial a 99,5% na presença de quantidades equivalentes de hidróxido, metóxido, etóxido e gliceróxido de sódio como catalisadores. Com o uso dos três alcóxidos obteve-se a separação do glicerol formado durante a reação, o que não ocorreu com o uso de hidróxido de sódio. O rendimento de sódio, como catalisador na transesterificação, apresenta vantagens econômicas e tecnológicas quando comparado com o hidróxido de sódio.bitstream/item/65433/1/CTAA-DOCUMENTOS-12-TRANSESTERIFICACAO-DE-OLEO-DE-SOJA-COM-DIVERSOS-CATALISADORES-ALCALINOS-FL-021.pd

Experimental and theoretical lifetimes and transition probabilities in Sb I

We present experimental atomic lifetimes for 12 levels in Sb I, out of which seven are reported for the first time. The levels belong to the 5p$^2$($^3$P)6s $^{2}$P, $^{4}$P and 5p$^2$($^3$P)5d $^{4}$P, $^{4}$F and $^{2}$F terms. The lifetimes were measured using time-resolved laser-induced fluorescence. In addition, we report new calculations of transition probabilities in Sb I using a Multiconfigurational Dirac-Hartree-Fock method. The physical model being tested through comparisons between theoretical and experimental lifetimes for 5d and 6s levels. The lifetimes of the 5d $^4$F$_{3/2, 5/2, 7/2}$ levels (19.5, 7.8 and 54 ns, respectively) depend strongly on the $J$-value. This is explained by different degrees of level mixing for the different levels in the $^4$F term.Comment: 10 page