3,018 research outputs found
Dinâmica recente no espaço rural do município de Nossa Senhora da Glória/SE.
O objetivo desse artigo é analisar a dinâmica recente no espaço rural de um município do semi-árido sergipano, reconhecido pelo dinamismo da sua economia que gira em torno da produção e processamento do leite por agricultores familiares, a despeito da inexistência de políticas específicas e continuadas para esse fim. A área de pesquisa é o município de Nossa Senhora da Glória localizado no Alto Sertão sergipano. A metodologia privilegiou o contato com atores-chave através de entrevistas, observações de campo, caminhadas transversais para observação da paisagem, participação em reuniões e levantamento de dados secundários. Os principais resultados demonstram que o município de Glória contem na sua totalidade três unidades de desenvolvimento com dinâmicas particulares a depender das estratégias dos agricultores, acesso e qualidade dos recursos naturais e vinculação com os mercados (trabalho, produto e financeiro
Evolution from BCS to BKT superfluidity in one-dimensional optical lattices
We analyze the finite temperature phase diagram of fermion mixtures in
one-dimensional optical lattices as a function of interaction strength. At low
temperatures, the system evolves from an anisotropic three-dimensional
Bardeen-Cooper-Schrieffer (BCS) superfluid to an effectively two-dimensional
Berezinskii-Kosterlitz-Thouless (BKT) superfluid as the interaction strength
increases. We calculate the critical temperature as a function of interaction
strength, and identify the region where the dimensional crossover occurs for a
specified optical lattice potential. Finally, we show that the dominant vortex
excitations near the critical temperature evolve from multiplane elliptical
vortex loops in the three-dimensional regime to planar vortex-antivortex pairs
in the two-dimensional regime, and we propose a detection scheme for these
excitations.Comment: 4 pages with 2 figure
Phase Fluctuations and Vortex Lattice Melting in Triplet Quasi-One-Dimensional Superconductors at High Magnetic Fields
Assuming that the order parameter corresponds to an equal spin triplet
pairing symmetry state, we calculate the effect of phase fluctuations in
quasi-one-dimensional superconductors at high magnetic fields applied along the
y (b') axis. We show that phase fluctuations can destroy the theoretically
predicted triplet reentrant superconducting state, and that they are
responsible for melting the magnetic field induced Josephson vortex lattice
above a magnetic field dependent melting temperature Tm.Comment: 4 pages (double column), 1 eps figur
Counting States: A Combinatorial Analysis of SQM Fragmentation
The Strange Quark matter (SQM) hypothesis states that at extreme pressure and
density conditions a new ground state of matter would arise, in which half of
the \textit{down} quarks become strange quarks. If true, it would mean that at
least the core of neutron stars is made of SQM. In this hypothesis, SQM would
be released in the inter-stellar medium when two of these objects merge. It is
estimated that of SQM would be released this way. This matter
will undergo a sequence of processes that should result in a fraction of the
released SQM becoming heavy nuclei through \textit{r-process}. In this work we
are interested in characterizing the fragmentation of SQM, with the novelty of
keeping track of the \textit{quark configuration} of the fragmented matter.
This is accomplished by developing a methodology to estimate the energy of each
fragment as the sum of its \textit{constituent quarks}, the Coulomb interaction
among the quarks and fragments' momenta. The determination of the fragmentation
output is crucial to fully characterize the subsequent nucleosynthesis.Comment: 4 pages, 2 figures, 2 table
Método para classificar bovinos resistentes à infecção por Babesia bovis.
Descreve a metodologia de desafio para a identificação de bovinos resistentes ou suscetíveis à primo-infecção por B. bovis para fins experimentais.bitstream/item/55805/1/CO65.pdfDsiponível no formato online
Diversidade das unidades e dos produtores de derivados do leite em Nossa Senhora da Glória, semi-árido sergipano.
Thermodynamically stable noncomposite vortices in mesoscopic two-gap superconductors
In mesoscopic two-gap superconductors with sizes of the order of the
coherence length noncomposite vortices are found to be thermodynamically stable
in a large domain of the phase diagram. In these phases the vortex
cores of one condensate are spatially separated from the other condensate ones,
and their respective distributions can adopt distinct symmetries. The
appearance of these vortex phases is caused by a non-negligible effect of the
boundary of the sample on the superconducting order parameter and represents
therefore a genuine mesoscopic effect. For low values of interband Josephson
coupling vortex patterns with can arise in addition to the
phases with , where and are total vorticities in the two
condensates. The calculations show that noncomposite vortices could be observed
in thin mesoscopic samples of MgB.Comment: 5 pages, 3 figures, to be published in Europhysics Letter
A micromechanical constitutive model for ductile fracture: numerical treatment and calibration strategy
This contribution describes the numerical treatment and calibration strategy for a new micromechanical damage model, which employs two internal damage variables. The new micromechanical model is based on Gurson's theory incorporating the void volume fraction as one damage parameter and a shear mechanism, which was formulated considering geometrical and phenomenological aspects, as the second internal damage variable. The first and the second damage variables are coupled in the constitutive formulation in order to affect the hydrostatic stress and
deviatoric stress contributions, respectively. Both internal damage variables are independent and, as a consequence, they also require independent nucleation mechanisms for each one in order to trigger the growth contribution. These mechanisms require the determination of material parameters that are obtained through two calibration points: one for high and the other for low stress triaxiality. This is in contrast to other damage models that typically require one calibration point. In the first part of this paper, theoretical aspects of the constitutive formulation are presented and discussed. Then, an implicit numerical integration algorithm is derived, based on the operator split methodology, together with a methodology to perform the calibration of all material parameters. In order to assess the performance of the new model, the “butterfly” specimen was used and the 1045 steel was employed under a wide range of stress triaxiality. The results obtained from the numerical simulations are presented such as: the evolution of both damage parameters, the evolution of the equivalent plastic strain, the reaction versus displacement curve and the contour
of the effective damage parameter. From the comparison of the numerical results with experimental evidence, it will be highlighted that the present formulation is able to predict accurately the location of fracture onset and the level of the associated equivalent plastic strain at fracture
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