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In maize plant breeding aimed at producing a hybrid, it is necessary to characterize the parents and hybrids by their agronomic aspects and grain quality so that the processing industry may offer consumers a quality product and also improve its efficiency. This study evaluated the viscoelastic parameters of masa and the chemical and texture properties of tortillas obtained from parent lines (M-54, M55, and CML-242), two single crosses (M54xM55 and M55xM54), and one hybrid (H-70). The morphology of the maize grains and tortillas was analyzed using scanning electron microscopy. The firmness of masa obtained from CML-242 and H-70 maize was higher than that from the other maize genotypes. M-54 tortillas showed the lowest crude fiber content. Otherwise, tortillas obtained from the M55xM54 hard grain had the lowest fat content and extensibility, while H-70 tortillas showed an intermediate breaking point and extensibility. M-54 and M54xM55 tortillas were softer due to their more swollen starch granules. In contrast, rigid tortillas were obtained from CML-242 and H-70. Grain hardness causes different morphology in starch and tortilla of maize genotypes. However, grain hardness did not influence the characteristics of texture in tortillas [ABSTRACT FROM AUTHOR]

The exact solutions for the two-dimensional motion of a conduction band electron in a disc shaped quantum dot under the effect of an external magnetic field and parabolic and inverse square confining potentials are used to calculate the linear and nonlinear optical absorption as well as the linear and nonlinear corrections to the refractive index in the system. It is shown that this kind of structure may work well as a model for a quantum ring. Using the basic parameters typical of the GaAs, the results show that the influence of the normally oriented magnetic field induces a blueshift in both the first and third order peaks of the calculated optical quantities. In addition, total peak amplitudes are shown to be growing functions of the magnetic field strength. The increase in the strength of the inverse square potential function enhances significantly the contribution from the nonlinear third-order terms in both the absorption and the relative correction to the refractive index. [ABSTRACT FROM AUTHOR]

We evaluate the forage yield and quality, species composition, and carrying capacity of oats and oat-vetch as fodder-cover crops, grown in almond orchards, under mineral or organic fertilizer and three harvesting regimes ('grazing,' 'hay,' and 'grain plus straw'). Also, we show preliminary results of almond yield. Differences in yield due to mineral and organic fertilization were only 9%. The carrying capacity was similar for all treatments. The almond yield was greater when the cover crop was removed early as 'grazing.' Therefore, oats and oat-vetch could be used as cover crops in almond orchards if removed early by livestock grazing. [ABSTRACT FROM AUTHOR]

The microstructure of an automobile gear made by the powder metallurgy process was studied using scanning electron microscopy and optical microscopy with further computer analyzing of images. The investigation of the electrical properties of the gear was done employing standard resistivity measurements and analyzed using an original method to determine the local orientation of the electric field. This last method provided us with the distribution of the electric current lines, which clearly reflects the local anisotropy and fractures in the material. We found that the electric resistivity in the specimens studied is extremely sensitive to the porosity of the material. It is shown that none of the existing theories of the electric conductivity of composite materials, including the Maxwell theory and the frequently used "brick model:' are able to explain this supersensitive dependence on porosity. A new approach is developed, taking into account the anisotropic character of the material. The results of this modeling have shown a good agreement with experimental results. The new method of electric field mapping may be recommended for investigation of the other structural materials. The model developed might be useful, in particular, for a discussion of the influence of the pores on their mechanical properties. [ABSTRACT FROM AUTHOR]