531 research outputs found
Obtenção de nanofibras de celulose a partir de fibras de sisal para atuar como reforço em matrizes biodegradáveis.
Fibras eletrofiadas funcionalizadas com híbrido nanocelulose/nanopartículas de prata para aplicação em sensores e biosensores.
Propriedades mecânicas e morfológicas do nanocompósitod de Amido Termoplástico e Policaprolactona com whiskers de celulose de sisal.
Nanofibras de celulose obtidas a partir de fibras de sisal branqueadas com solução alcalina de peróxido de hidrogênio.
He II 4686 emission from the massive binary system in Car: constraints to the orbital elements and the nature of the periodic minima
{\eta} Carinae is an extremely massive binary system in which rapid spectrum
variations occur near periastron. Most notably, near periastron the He II
line increases rapidly in strength, drops to a minimum value,
then increases briefly before fading away. To understand this behavior, we
conducted an intense spectroscopic monitoring of the He II
emission line across the 2014.6 periastron passage using ground- and
space-based telescopes. Comparison with previous data confirmed the overall
repeatability of EW(He II ), the line radial velocities, and the
timing of the minimum, though the strongest peak was systematically larger in
2014 than in 2009 by 26%. The EW(He II ) variations, combined
with other measurements, yield an orbital period d. The observed
variability of the EW(He II ) was reproduced by a model in which
the line flux primarily arises at the apex of the wind-wind collision and
scales inversely with the square of the stellar separation, if we account for
the excess emission as the companion star plunges into the hot inner layers of
the primary's atmosphere, and including absorption from the disturbed primary
wind between the source and the observer. This model constrains the orbital
inclination to -, and the longitude of periastron to
-. It also suggests that periastron passage occurred on
d. Our model also reproduced EW(He II )
variations from a polar view of the primary star as determined from the
observed He II emission scattered off the Homunculus nebula.Comment: The article contains 23 pages and 17 figures. It has been accepted
for publication in Ap
Vitamin C content in Habanero pepper accessions (Capsicum chinense)
O objetivo deste trabalho foi quantificar o teor devitamina C em 22 acessos de C. chinense do grupo varietal 'Habanero", procedentes do programa de melhoramento genético da Embrapa Hortaliças
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