[en] The (constrained) canonical reduction of four-dimensional self-dual Yang-Mills theory to Burgers' type, two-dimensional sine-Gordon, generalized Korteweg-de Vries-type, (2+1)- and the original (3+1)- dimensional Liouville equations are considered. On the one hand, the Backlund transformations are implemented to obtain several classes of exact solutions for the reduced Burgers-type and two-dimensional sine-Gordon equations. On the other hand, other methods and transformations are developed to obtain exact for the original two-dimensional generalized Korteweg-de Vries-type, (2+1)- and the original (3+1)-dimensional Liouville equations. The corresponding gauge potential A, and the gauge strenghts F μν are also obtained

[en] Zinc oxide thin films were deposited on a glass substrate by spray pyrolysis technique using solution of zinc acetate and air as the carrier gas. Effects of solution molarity, substrate temperature and spray time on films properties were investigated. All films deposited were characterized using X-ray diffraction for structural characterization and UV-VIS transmission spectrophotometry for optical properties. According to the analytical method, the type of crystal lattice was found to be hexagonal and X-ray diffraction (XRD) patterns showed that the films deposited were polycrystalline with (002) plane as preferential orientation. The values of lattice constant, grain size, micro strain and dislocation density of all samples were calculated. In addition, Optical behaviors of film samples were analyzed by obtaining transmission spectra, in the wavelength range of 350-800 nm. The UV-VIS spectroscopy shows the high transparency of ZnO films in the UV region. An optimization of the films has been carried out to determine the best preparation conditions.

[en] The effect of gamma irradiation on the features of pure magnesium oxide MgO, titanium oxide TiO₂ and MgO-TiO₂ binary oxides synthesized by sol-gel method with different MgO molar ratios have been investigated. The irradiated and un-irradiated oxides were characterized by Fourier Transform Infrared spectroscopy (FTIR), UV–vis spectroscopy and thermogravimetric analysis (TGA). The induced changes in the FTIR spectra of both un-irradiated and irradiated samples were observed by a slight shift in the transmittance spectra. Furthermore, the results obtained from the optical absorption measurements reflected a great dependence on the fundamental absorption edge of the irradiation dose. It was found that the band gap values of the un-irradiated oxides decreased with increasing the MgO molar ratios. Moreover, by increasing the irradiation dose up to 75 kGy, the band gap of irradiated samples decreased with the same behavior of un-irradiated samples. On the other hand, the thermal investigations proved that changing the molar ratios of MgO had an effect on both phase composition and thermal stability of binary oxides. The theoretical investigations were separately studied as a function of the average electronegativity with bond energy calculation. (paper)

[en] Qarun Lake is one of the most important lakes in Egypt; it is the shrunken remnant of Moeris Lake. It is a closed ecosystem represented as a tank for discharged agricultural wastewater of El-Fayoum province. To assess the quality of the lake water for fishing and aquatic live utilization, Oregon water quality and metal pollution indices are computed. Based on the obtained results, water of the Qarun Lake is classified as very poor for the fishing utilization, where water quality index changed from 17.05 to 67.4 at the different stations. The metal indices; Pollution index (PI) and metal index (MI); showed that Qarun Lake water undergoes from a several grade of contamination for usage of aquatic life because of the enormous amount of wastes that discharging into the lake. Novel synthesized alginate nanocomposites (alginate, chitosan-alginate, and LDH-alginate and LDH-chitosan-alginate beads) were applied to remove heavy metal such as (Cd²⁺, Cu²⁺, Cr⁶⁺, Mn²⁺, Fe²⁺, Ni²⁺, Pb²⁺, and Zn²⁺) from different wastewater discharging into Qarun Lake. LDH-chitosan-alginate beads the exhibited the maximum removal efficiency that varied between 92.253 and 98.833 % for Cr⁶⁺ and Fe²⁺, respectively; in contrast, the alginate beads recorded the lowest one. The study indicated that the nanocomposite adsorbents, especially, LDH-chitosan-alginate beads are an effective substance for metal removal from different wastewater. (paper)