Lítio e parâmetros orbitais em sistemas binários com componentes evoluídas

One of the best established properties of the single late type evolved stars is that their rotational velocity and lithium content decrease with effective temperature and age. Nevertheless, the root cause of this property, as well as the link between rotation and lithium abundance and, in particular, the effects of binarity on rotation and lithium content in binary systems with evolved component, are not yet completely established. How does the gravitational tides, in binary systems, affects rotational evolution and lithium dilution? Trying to answer these questions, we have carried out an observational survey, in the lithium region centered at the lithium I line A6707.81A, for a large sample of about 100 binary systems with evolved component along the spectral range F, G and K, with the CES spectrometer mounted at the CAT 1.44 m Telescope of the ESO, La Silla, Chile. By combining the abundances of lithium issued from these observations with rotational velocity and orbital parameters, we have found a number of important results. First of all, we confirm that in this class of binary systems rotation is effectively affected by tidal effects. Binary systems with orbital period lower than about 100 days and circular or nearly circular orbits, present rotational velocity enhanced in relation to the single giant stars and to the binary systems with an orbital period larger than 100 days. This is clearly the result of the synchonization between the rotational and orbital motions due to tidal effects. In addition, we have found that lithium abundances in binary systems with giant components present the same gradual decreasing with effective temperature, observed in the single giants of same luminosity class and spectral types. We have found no lithium-rich binary systems, in contrast with single giants. A remarkable result from the present study is the one showing that synchronized binary systems with giant component retains more of their original lithium than the unsynchronized systems. In fact, we have found a possible "inhibited zone", in which synchronized binary systems with giant component having lithium abundance lower than a threshold level should be unusual. Finally, the present study also shows that the binary systems with giant component presenting the highest lithium contents are those with the highest rotation rates

Síntese e caracterização do líquido iônico tetrafluoroborato de 1-metil-3-(2,6-(S)-dimetiloct-2-eno)-imidazol como eletrólito para produção de hidrogênio via eletrólise da água

Ionic liquids (ILs) are organic compounds liquid at room temperature, good electrical conductors, with the potential to form as a means for electrolyte on electrolysis of water, in which the electrodes would not be subjected to such extreme conditions demanding chemistry [1]. This paper describes the synthesis, characterization and study of the feasibility of ionic liquid ionic liquid 1-methyl-3(2,6-(S)-dimethyloct-2-ene)-imidazole tetrafluoroborate (MDI-BF4) as electrolyte to produce hydrogen through electrolysis of water. The MDI-BF4 synthesized was characterized by thermal methods of analysis (Thermogravimetric Analysis - TG and Differential Scanning Calorimetry - DSC), mid-infrared spectroscopy with Fourier transform by method of attenuated total reflectance (FTIR-ATR), nuclear magnetic resonance spectroscopy of hydrogen (NMR 1H) and cyclic voltammetry (CV). Where thermal methods were used to calculate the yield of the synthesis of MDI-BF4 which was 88.84%, characterized infrared spectroscopy functional groups of the compound and the binding B-F 1053 cm-1; the NMR 1H analyzed and compared with literature data defines the structure of MDI-BF4 and the current density achieved by MDI-BF4 in the voltammogram shows that the LI can conduct electrical current indicating that the MDI-BF4 is a good electrolyte, and that their behavior does not change with the increasing concentration of water

Já li muita coisa, então, eu posso inventar mais! A leitura literária e o desenvolvimento do pensamento criativo na infância

This study investigates the contributions of reading literature for the development of creative thinking in childhood. Its relevance consists in exploring practices that contemplate the creative thinking development in apprentices at school space and understanding the literature like a significant way to promote the creative thinking. The study is connected to the qualitaty strand. The exploratory observation and the intervention were adopted as research techniques. The field diary and the audio and video recording of the reading sections were adopted as methodological instruments. The research was conducted in the application s college from the Federal University of Rio Grande do Norte, in a 1th grade class, with 18 students between 6 and 7 years old. During the intervention, 8 readind class happened, with varied strategies and literary genres. The reading sessions were conducted through the principles of scaffolding, defended by Graves and Graves (1995). The corpus is made of speaks episodes, whose encoding semantics allowed the grouping into two central categories: divergent thinking and coauthoring of literary reader. It was taken as a theoretical framework the studies of Amarilha (2011; 2006; 2001; 1991; 1993; 1994), Alencar (2001), Coelho (2000; 1997), Culler (1999), De Masi (2005), Gallo (2000), Guilford (1977), Iser (1996), Jouve (2002), Kneller (1978), Martínez (1997), Smith (2003), Stierle (1979), Vigotski (2009; 1998), Wechsler; Nakano (2003; 2002). The analysis points to the formation of creative individuals in the classroom, through the reading of literature. Reposition the literary education front of the new social demands. Resizes the function of school in children s development, considering the children s skill in exploring, testing hypotheses and making use of their creative thinking, in climate of freedom mental. It signals, in this way, the teacher like a mediator, promoting a favorable to the development of creative thinking environment, a stimulating atmosphere, which enhances the expression of creative thinking in community