Additive aluminum powder to the polystyrene to prepare the composites Polystyrene– Aluminum.The samples were prepared by using mechanical compressed method at low pressure and a temperature 120°C. Measurements of absorbance and reflectance spectra were carried out by UV-Visible spectrophotometer , the effect of additive aluminum on the optical band gap Eop and optical constants ( refractive index n, extinction coefficient k ,dielectric constant ε and optical conductivity σop) were studied for the prepared composites . Results showed a decrease in the Eop with increasing percent of aluminum from 4.1eV for pure polystyrene to about 3.12eV for the composite Ps+30%Al. Values of each of n and k show observable changes, these changes are associated with the increase in scattering, reflection, and optical absorption on the film surface with the increase of Al percentage. The dielectric constant of Ps-Al composites is greater for all Al concentrations and may be attributed to interfacial polarization in the heterogeneous media, it was observed that the optical conductivity increasing from 0.12×105S.cm-1 for pure polystyrene to about 1.32×108S.cm-1 for Ps+30%Al. These results indicate that the optical properties of PS-Al composites can be controlled by the appropriate selection of Al concentration and the optical properties of the composites can be modified by the addition of impurities ,thus increase the industrial application for the composites.
In this paper three techniques for image compression are implemented. The proposed techniques consist of three dimension (3-D) two level discrete wavelet transform (DWT), 3-D two level discrete multi-wavelet transform (DMWT) and 3-D two level hybrid (wavelet-multiwavelet transform) technique. Daubechies and Haar are used in discrete wavelet transform and Critically Sampled preprocessing is used in discrete multi-wavelet transform. The aim is to maintain to increase the compression ratio (CR) with respect to increase the level of the transformation in case of 3-D transformation, so, the compression ratio is measured for each level. To get a good compression, the image data properties, were measured, such as, image entropy (He), percent root-
... Show MoreLet R be a commutative ring with unity and an R-submodule N is called semimaximal if and only if
the sufficient conditions of F-submodules to be semimaximal .Also the concepts of (simple , semisimple) F- submodules and quotient F- modules are introduced and given some properties .
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