Management of nitrogen fertilization on agronomic and nutritional characteristics in second crop corn

Fertilization management, mainly nitrogen, is one of the factors that most directly affect corn grain yield. Nitrogen dynamics in the soil is quite complex and its main source currently used in corn production, the urea, undergo intense losses in its conventional form, mainly by volatilization and leaching. Thus, the aim of this study was to assess the effect of forms, sources, and times of nitrogen application on the second crop corn. The experiment was conducted in 2016 in the Fundação Chapadão, Chapadão do Sul, MS, Brazil. The sources conventional urea, polymer-coated urea, and foliar N (8 treatments) were used as follows: control (without N addition), conventional urea (single in V3 and split in V3 and V6), polymer-coated urea (single in V3 and split in V3 and V6), conventional urea + foliar N (conventional urea in V6 and foliar in pre-flowering), polymer-coated urea + foliar N (polymer-coated urea in V6 and foliar in pre-flowering), and foliar N (split in V6 and pre-flowering). The variables stem diameter, ear index, ear length, number of grains per row, number of rows per ear, plant height, first ear height, leaf chlorophyll index, leaf N index, leaf values of Ca, Mg, Fe, Zn, Mn, and Cu, 100-grain weight, and grain yield were assessed. Nitrogen application in the form of conventional urea, polymer-coated urea, and foliar N (single or split) for second crop corn does not result in distinct benefits for the crop. Thus, attention should be paid to the commercialization of the product, which has prices established according to nitrogen forms, but without result, for example, in grain yield, which in fact will compose the producer income. The applied nitrogen form and mode of application were positive only to increase the contents of Ca, Mg, Zn, and Mn in the leaves of second crop corn. Ca was favored by the use of conventional urea and split conventional urea, Mg and Mn were only benefited by foliar N application, and Zn was benefited by the use of conventional urea, split conventional urea, conventional urea + foliar N, and polymer-coated urea+foliar N

Desenvolvimento de um dispositivo para obtenção de monocristais de ligas à base de cobre

This paper describes the drawing, construction and optimization of a device, which can be used to obtain single crystals of different metallic materials with melting point from 550 to 1050 ºC. Components of ease obtaining and of low cost were used. The device was based on the modified Bridgman technique and it was used to obtain single crystals of copper-based alloys. The temperature axial profiles and a difference less then 1% in the temperature between the wall and the center of the ceramic tube in the critical region for obtaining single crystals of good quality indicated that the oven presents a good thermal stability. Single crystals of CuZnAl and CuAlAg alloys of good quality were growth and characterized using optical microscopy and Laüe X-ray back reflection

Desenvolvimento de um dispositivo para obtenção de monocristais de ligas à base de cobre

This paper describes the drawing, construction and optimization of a device, which can be used to obtain single crystals of different metallic materials with melting point from 550 to 1050°C. Components of ease obtaining and of low cost were used. The device was based on the modified Bridgman technique and it was used to obtain single crystals of copper-based alloys. The temperature axial profiles and a difference less then 1% in the temperature between the wall and the center of the ceramic tube in the critical region for obtaining single crystals of good quality indicated that the oven presents a good thermal stability. Single crystals of CuZnAl and CuAlAg alloys of good quality were growth and characterized using optical microscopy and Laüe X-ray back reflection

Laüe back-reflection method for crystallographic orientation of a martensitic Cu-Zn-Al single crystal of the monoclinic system

A martensitic single crystal Cu-23.95Zn-3.62(wt.%)Al alloy was obtained melting pure Cu, Zn and Al using Bridgman's method. The martensitic phase (monoclinic) can present up to 24 variants, and orienting the surface according to a certain plane is a very hard task. The single crystal was submitted to 8 tons of tension (stress) along the longitudinal direction to reduce the number of variants and facilitate the surface orientation according to the desired plane. This single crystal was oriented using the Laüe back-reflection method to give surfaces with the following oriented crystallographic planes: (010), (120) and (130). It was observed that the tension stress was applied along the [010] direction.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Local Electrochemical Investigation of Single Grains of Polycrystalline Cu-16%Zn-8%Al Alloy

Local electrochemical studies of single grains of a polycrystalline Cu-16%Zn-8%Al alloy were investigated in borate buffer solution (pH 8.4) by means of microelectrochemical technique. The grain orientations, which were determined by the Laue back-reflection method, were predominantly close to [110] direction, suggesting that the sample was texturized. The open circuit potential measurements showed that the lower steady state potential was observed for the grain which has the highest number of steps on the alloy surface. The cyclic voltammetry experiments suggested that the orientation of Cup follows the substrate one in the Cu-Zn-Al alloy, while CuO grows independently.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq