Mg/Ti multilayers: structural, optical and hydrogen absorption properties

Mg-Ti alloys have uncommon optical and hydrogen absorbing properties, originating from a "spinodal-like" microstructure with a small degree of chemical short-range order in the atoms distribution. In the present study we artificially engineer short-range order by depositing Pd-capped Mg/Ti multilayers with different periodicities and characterize them both structurally and optically. Notwithstanding the large lattice parameter mismatch between Mg and Ti, the as-deposited metallic multilayers show good structural coherence. Upon exposure to H2 gas a two-step hydrogenation process occurs, with the Ti layers forming the hydride before Mg. From in-situ measurements of the bilayer thickness L at different hydrogen pressures, we observe large out-of-plane expansions of the Mg and Ti layers upon hydrogenation, indicating strong plastic deformations in the films and a consequent shortening of the coherence length. Upon unloading at room temperature in air, hydrogen atoms remain trapped in the Ti layers due to kinetic constraints. Such loading/unloading sequence can be explained in terms of the different thermodynamic properties of hydrogen in Mg and Ti, as shown by diffusion calculations on a model multilayered systems. Absorption isotherms measured by hydrogenography can be interpreted as a result of the elastic clamping arising from strongly bonded Mg/Pd and broken Mg/Ti interfaces

Estratégias de comercialização do feijão produzido por agricultores familiares da região Leste de Goiás.

A pesquisa teve como objetivo principal identificar as estratégias de comercialização do feijão oriundo da agricultura familiar, assim como a principal safra, as variedades produzidas e o destino dessa produção de feijão.CONAF

Efeito do ácido indol butírico e do carvão ativado no enraizamento in vitro de brotos de abacaxi ornmental (Ananas lucidus Miller).

A micropropagação poderá ser uma alternativa viável para aumentar o número de plantas por ano com a mesma característica genética, independente da época do ano e em menor espaço de tempo. O objetivo deste estudo foi avaliar o efeito do ácido indol butírico e do carvão ativado no enraizamento in vitro de brotos de abacaxi ornamental.bitstream/CNPAT-2010/8953/1/Pa-066.pd

Análise quantitativa da proteína total de reserva do grão em acessos de arroz irrigado da coleção nuclear da Embrapa (CNAE).

Este trabalho objetivou quantificar a proteína total de reserva de 186 acessos com sistema de cultivo irrigado da CNAE e observar se estes acessos apresentam variabilidade em relação ao teor protéico

Critical Hysteresis from Random Anisotropy

Critical hysteresis in ferromagnets is investigated through a $N$-component spin model with random anisotropies, more prevalent experimentally than the random fields used in most theoretical studies. Metastability, and the tensorial nature of anisotropy, dictate its physics. Generically, random field Ising criticality occurs, but other universality classes exist. In particular, proximity to $\mathcal{O}(N)$ criticality may explain the discrepancy between experiment and earlier theories. The uniaxial anisotropy constant, which can be controlled in magnetostrictive materials by an applied stress, emerges as a natural tuning parameter.Comment: four pages, revtex4; minor corrections in the text and typos corrected (published version

Influência dos meios de cultura sólido e líquido no alongamento de brotos in vitro de abacaxi ornamental (Ananas lucidus Miller).

Influencia dos meios de cultura solido e liquido no alongamento de brotoss in vitro de abacaxi ornamental.bitstream/CNPAT-2010/5395/1/Pa-057.pd