188 research outputs found
The anisotropic Ashkin-Teller model: a renormalization group study
The two-dimensional ferromagnetic anisotropic Ashkin-Teller model is
investigated through a real-space renormalization-group approach. The critical
frontier, separating five distinct phases, recover all the known exacts results
for the square lattice. The correlation length and crossover
critical exponents are also calculated. With the only exception of the
four-state Potts critical point, the entire phase diagram belongs to the Ising
universality class.Comment: 3 ps figures, accepted for publication in Physica
Probiotics on performance, intestinal morphology and carcass characteristics of broiler chickens raised with lower or higher environmental challenge
A p-Spin Interaction Ashkin-Teller Spin-Glass Model
A p-spin interaction Ashkin-Teller spin glass, with three independent
Gaussian probability distributions for the exchange interactions, is studied by
means of the replica method. A simple phase diagram is obtained within the
replica-symmetric approximation, presenting an instability of the paramagnetic
solution at low temperatures. The replica-symmetry-breaking procedure is
implemented and a rich phase diagram is obtained; besides the paramagnetic
phase, three distinct spin-glass phases appear. Three first-order critical
frontiers are found and they all meet at a triple point; among such lines, two
of them present discontinuities in the order parameters, but no latent heat,
whereas the other one exhibits both discontinuities in the order parameters and
a finite latent heat.Comment: 17 pages, 2 figures, submitted to Physica
On the physico-mechanical, electrical and dielectric properties of mullite-glass composites
Mullite-glass composites were obtained by solid-state reactive sintering of kaolinite clay and kaolin waste mixtures with waste additions up to 100 wt%. The structural and microstructural analysis of starting powders and sintered samples were evaluated by X-ray diffractometry (XRD) and field-emission scanning electron microscopy (FESEM). The mechanical properties were evaluated by measuring the flexural strength of sintered bodies. Electrical properties of the composites were assessed by impedance spectroscopy (at 30 °C and from 400 to 700 °C) in air. A viscous flux mechanism resulting from the glassy phase filled up the open porosity and increased the mechanical strength. Electrical conductivity, dielectric constant and dielectric loss were strongly dependent on the microstructural features, namely glassy phase and porosity. The activation energies (0.89–0.99 eV) for electrical conduction were lower than typical literature values of mullite-based materials. The results indicated that the herein synthesized mullite-glass composites with up to 53.6 wt% mullite are promising low-cost materials for electronics-related applications.publishe
Cinética dos anticorpos de origem colostral contra a toxina épsilon de Clostridium perfringens tipo D em cordeiros
Implantação de pastagens sob sistema monocultivo e integrado com lavoura utilizando biofertilizante de cama de aviário como adubação de cobertura
Kinetics of epsilon antitoxin antibodies in different strategies for active immunization of lambs against enterotoxaemia
Biostimulation of inoculation with Glomus proliferum and application of humic acid in the in vitro growth of Lunularia cruciata
Época e Densidade de Semeadura de Aveia Preta (Avena strigosa Schreb.) e Azevém (Lolium multiflorum Lam.) no Alto Vale do Itajaí, Santa Catarina
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