41 research outputs found
Metastable liquid lamellar structures in binary and ternary mixtures of Lennard-Jones fluids
We have carried out extensive equilibrium molecular dynamics (MD) simulations
to investigate the Liquid-Vapor coexistence in partially miscible binary and
ternary mixtures of Lennard-Jones (LJ) fluids. We have studied in detail the
time evolution of the density profiles and the interfacial properties in a
temperature region of the phase diagram where the condensed phase is demixed.
The composition of the mixtures are fixed, 50% for the binary mixture and
33.33% for the ternary mixture. The results of the simulations clearly indicate
that in the range of temperatures K, --in the scale of
argon-- the system evolves towards a metastable alternated liquid-liquid
lamellar state in coexistence with its vapor phase. These states can be
achieved if the initial configuration is fully disordered, that is, when the
particles of the fluids are randomly placed on the sites of an FCC crystal or
the system is completely mixed. As temperature decreases these states become
very well defined and more stables in time. We find that below K,
the alternated liquid-liquid lamellar state remains alive for 80 ns, in the
scale of argon, the longest simulation we have carried out. Nonetheless, we
believe that in this temperature region these states will be alive for even
much longer times.Comment: 18 Latex-RevTex pages including 12 encapsulated postscript figures.
Figures with better resolution available upon request. Accepted for
publication in Phys. Rev. E Dec. 1st issu
Beta-decay in odd-A and even-even proton-rich Kr isotopes
Beta-decay properties of proton-rich odd-A and even-even Krypton isotopes are
studied in the framework of a deformed selfconsistent Hartree-Fock calculation
with density-dependent Skyrme forces, including pairing correlations between
like nucleons in BCS approximation. Residual spin-isospin interactions are
consistently included in the particle-hole and particle-particle channels and
treated in Quasiparticle Random Phase Approximation. The similarities and
differences in the treatment of even-even and odd-A nuclei are stressed.
Comparison to available experimental information is done for Gamow-Teller
strength distributions, summed strengths, and half-lives. The dependence of
these observables on deformation is particularly emphasized in a search for
signatures of the shape of the parent nucleus.Comment: 29 pages, 16 figure
Estímulo no crescimento e na hidrólise de atp em raízes de alface tratadas com humatos de vermicomposto: ii - efeito da fonte de vermicomposto.
Um dos fatores mais limitantes para a produção de vermicomposto é a disponibilidade de esterco. Neste trabalho, foi avaliado o efeito da substituição parcial do esterco por bagaço de cana e por resíduos de leguminosa (Gliricidia sepium) na vermicompostagem sobre a qualidade do vermicomposto e sobre a bioatividade dos humatos, avaliadas por meio da análise do crescimento radicular e da atividade das bombas de H+ isoladas de raízes de alface. A substituição do esterco por bagaço de cana e por resíduos de leguminosas não acarretou prejuízo às características químicas dos vermicompostos. No entanto, os humatos isolados
dos diferentes vermicompostos apresentaram características químicas distintas,tais como: acidez e propriedades óticas distintas. Os humatos produzidos a partir de esterco de bovino e da mistura esterco bovino + bagaço proporcionaram maiores estímulos no crescimento radicular das plantas de alface, sendo os mais indicados para uso na forma solúvel. A inclusão de resíduos de leguminosas no processo de vermicompostagem produziu humatos sem efeito sobre o desenvolvimento das raízes de alface