315 research outputs found
Critical temperature for first-order phase transitions in confined systems
We consider the Euclidean -dimensional
() model with () compactified dimensions.
Introducing temperature by means of the Ginzburg--Landau prescription in the
mass term of the Hamiltonian, this model can be interpreted as describing a
first-order phase transition for a system in a region of the -dimensional
space, limited by pairs of parallel planes, orthogonal to the coordinates
axis . The planes in each pair are separated by distances
. We obtain an expression for the transition temperature as
a function of the size of the system, , . For
D=3 we particularize this formula, taking for the
physically interesting cases (a film), (an infinitely long wire
having a square cross-section), and for (a cube). For completeness, the
corresponding formulas for second-order transitions are also presented.
Comparison with experimental data for superconducting films and wires shows
qualitative agreement with our theoretical expressionsComment: REVTEX, 11 pages, 3 figures; to appear in Eur. Phys. Journal
Pareto Autonomous Local Search
This paper presents a study for the dynamic selection of operators in a local search process. The main purpose is to propose a generic autonomous local search method which manages operator selection from a set of available operators, built on neighborhood relations and neighbor selection functions, using the concept of Pareto dominance with respect to quality and diversity. The latter is measured using two different metrics. This control method is implemented using the Comet language in order to be easily introduced in various constraint local search algorithms. Focusing on permutation-based problems, experimental results are provided for the QAP and ATSP to assess the method’s effectiveness
As boas práticas dos Sousa na criação bovina em babaçuais: Povoado de São Manoel, Lago do Junco, MA.
bitstream/item/214787/1/Mearim-Vol-15.pd
A roça agroecológica da família de dona Sibá e seu João Valdeci: Centrinho do Acrísio, Lago do Junco, MA.
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As boas práticas da família Pereira Santana: Sítio Novo, Lago do Junco, MA.
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A produção da família Alves de Sousa aliada à recuperação do solo: Centro do Bertolino, Lago do Junco, MA.
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A tradição da família de dona Belinha no cultivo do feijão abafado: Povoado do Lago do Sigismundo, Esperantinópolis, MA.
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