Maturidade fisiológica de sementes do híbrido simples BR 201 fêmea de milho (Zea mays L.) produzidas no inverno.

Sementes de milho hibrido simples BR 201 femea produzidas no periodo de inverno, foram colhidas em intervalos de sete dias, a partir do 30 dia apos a floracao ate o 128 com o objetivo de se estudar a maturidade fisiologica. as sementes foram analisadas quanto ao grau de umidade, materia seca, ocorrencia de camada preta, germinacao e vigor. Nas condicoes em que o trabalho foi realizado, os resultados permitiram chegar as seguintes conclusoes: a maturidade fisiologica das sementes, com base no acumulo de materia seca, ocorreu aos 58 dias apos a floracao- sementes de alta qualidade fisiologica podem ser obtidas com colheitas antecipadas em relacao ao maximo acumulo de materia seca, implicando em um intervalo otimo para colheita em ate 14 dias antes do ponto de maturidade fisiologica: a producao de sementes no inverno, permite a obtencao de sementes de alta qualidade, em menor espaco de tempo que no cultivo em epoca normal

Potencial forrageiro de espécies para cultivo no período de safrinha em solos de tabuleiros costeiros.

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EVALUATION OF PRESSURE DROP IN FLOW OVER FIXED POROUS BED

Many studies are conducted about the dynamics of fluids in porous media, which generates a number of factors and problems are solved. In particular the phenomenon of pressure drop in flows on fixed bed, although fairly well in the form Ergun’s equation, still has certain inconsistencies with regard to the types of materials to be used in the packaging of the beds. The objective of this work is to study this phenomenon using some experiments reported in the literature to determine the pressure drop in fixed bed consisting of porous particles of açaí seed. Experimental studies were conducted to predict, and take into account the losses resulting from friction and inertia that showed strong dependence on velocity. The method of using the particular friction factor prediction as a way to replace the usual calculation and measurement of pressure drop. The analysis in the wind tunnel was made from different sizes of bed, with a decrease in arithmetic progressions corresponding to half the value of the diameter of the tube used in the test. Several bands of Reynolds number were also employed in order to be able to visualize how the phenomenon behaves on various tracks. For such a survey was necessary some parameters such as açaí seeds diameters, seed weight and volume occupied by the bed; these parameters are of vital importance in Ergun equation, because an important aspect of the phenomenon is the porosity which enters as a foundation in the theory of flow fixed bed. At the end of the study was found the divergence in big bands of the Reynolds number of the correlation between experimental data and the Ergun equation

Avaliação preliminar de variedades de tangeleiros em Barcarena, Pará.

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