Nematic liquid crystal dynamics under applied electric fields

In this paper we investigate the dynamics of liquid crystal textures in a two-dimensional nematic under applied electric fields, using numerical simulations performed using a publicly available LIquid CRystal Algorithm (LICRA) developed by the authors. We consider both positive and negative dielectric anisotropies and two different possibilities for the orientation of the electric field (parallel and perpendicular to the two-dimensional lattice). We determine the effect of an applied electric field pulse on the evolution of the characteristic length scale and other properties of the liquid crystal texture network. In particular, we show that different types of defects are produced after the electric field is switched on, depending on the orientation of the electric field and the sign of the dielectric anisotropy.Comment: 7 pages, 12 figure

Estudos polarográficos do herbicida imazaquin.

bitstream/CNPDIA/9993/1/CT19_97.pd

Impacto do manejo da palhada sobre sua decomposição em área cultivada com cana-de-açúcar no município de Guaíra-SP.

O presente trabalho tem como objetivo acompanhar a dinâmica e as taxas finais de decomposição de diferentes quantidades de palhada de cana-de-açúcar, sob condições de Guaíra-SP. Para isto foi conduzido um experimento em área comercial de cana-de-açúcar, variedade RB 86-7515 na safra 2012-2013, em primeira soca. Como tratamentos foram testados os níveis T(25%), T(50%), T(75%) e T(100%), correspondentes a 4,7; 9,4; 14,1 e 18,8 t ha-1, distribuídos em blocos ao acaso, em quatro repetições. Para o acompanhamento da decomposição avaliou-se a quantidade (t ha-1) e a taxa (%) da massa seca remanescente no solo em coletas realizadas aos: 0, 63, 125, 189, 230, 285 e 328 dias após a instalação; utilizando-se de sacos de serapilheira ("litter bags") nas dimensões 0,50 x 0,75 com 15 mm de abertura. O tratamento estatístico foi feito por análise de variância, regressão e equações de cinética para ajuste do comportamento da decomposição da palhada. Os resultados permitiram concluir que os níveis de palhada alteram a dinâmica da decomposição deste resíduo, sendo o coeficiente de decomposição (K) significativamente superior para os níveis 100% e 75%. As maiores taxas de decomposição ocorrem até os 189 dias do ciclo, sendo mais lenta a partir deste ponto; com média de 41% de massa remanescente aos 328 dias, independente do nível de palhada. Abstract: The project aims to evaluate decomposition dynamic of different inputs of sugarcane straw under conditions of Guaira-SP. The experiment was conducted in a first ratoon commercial area of sugarcane, variety RB 86-7515, in 2012-2013. The treatments were tested by the levels of (25%), T(50%), T(75%) and T(100%), corresponding to 4,7; 9,4; 14,1 and 18,8 t ha -1 , arranged in a randomized block design, with four replications. The development of decomposition was evaluated using the quantity (kg ha -1 ) and the rate (%) remaining of dry matter, evaluated at: 0, 63, 125, 189, 230, 285, 328 days after installation by the use of litter bags (0,75m x 0,50m x 0,015m). The data were analyzed by variance, regression and kinetic equations for adjust the residues decomposition behavior. The results show that the levels of straw can modify the dynamics of this residue decomposition; the decomposition coefficient (K) was significantly higher for the levels of 100% and 75%. The highest rates of decomposition occur until 189 days of the cycle, being slower from this point; averaging 41% to the 328 days (harvest), regardless of the level of straw

Determinação do grau crítico de umidade em sementes de Cenostigma tocantinum Ducke e Dipteryx odorata Willd.

Este trabalho teve como objetivo avaliar o comportamento das sementes desta espécie quanto a sensibilidade à desidratação

The pasta phase within density dependent hadronic models

In the present paper we investigate the onset of the pasta phase with different parametrisations of the density dependent hadronic model and compare the results with one of the usual parametrisation of the non-linear Walecka model. The influence of the scalar-isovector virtual delta meson is shown. At zero temperature two different methods are used, one based on coexistent phases and the other on the Thomas-Fermi approximation. At finite temperature only the coexistence phases method is used. npe matter with fixed proton fractions and in beta-equilibrium are studied. We compare our results with restrictions imposed on the the values of the density and pressure at the inner edge of the crust, obtained from observations of the Vela pulsar and recent isospin diffusion data from heavy-ion reactions, and with predictions from spinodal calculations.Comment: 15 pages, 11 figures and 7 table

Influência da comunicação vibracional de percevejos no comportamento de busca de hospedeiros do parasitóide Telenomus podisi Ashmead.

bitstream/CENARGEN/29604/1/cot166.pd

Effects of molybdenum, nickel, and nitrogen sources on the mineral nutrition and growth of rice plants.

The aims of the current work were to measure the effect of Mo and Ni on dry-matter yield of rice plants supplied with two N sources (ammonium nitrate and urea) and to evaluate the influence of Mo and Ni on variables related to dry-matter yield, such as activity of both urease and nitrate reductase, chlorophyll, net photosynthesis rate, total N, nitrate content, and Mo and Ni concentrations in roots and shoots