A numerical groundwater model of the Nubian Aquifer System was established to prove the influence of rising seawater levels on the groundwater salinity in northern Egypt over the last 140,000years. In addition, the impact of a groundwater recharge scenario for these 140,000years, involving climatic change, on the saltwater/ freshwater interface was investigated. Saltwater intrusion induced by rising water levels of the Mediterranean Sea led to salinisation from the Mediterranean Sea to the Qattara depression. This modeling approach was supported by a density-driven model setup and calculation. The modelled saltwater/freshwater interfaces partially fitted the observed ones, especially in the southern half of the Qattara depression. In other parts of the northern Nubian Aquifer System, the ingression of salt water was modelled adequately, but in the west, small regions of the measured interface were not. The development in the Qattara depression (Egypt) and Sirte basin (Libya) were investigated in more detail. The different behaviour in the Sirte basin may be due to high evapotranspiration rates in some former periods, salt solutions from the pre- Quaternary layers or saltwater infiltration from sabkhalike recent salt-bearing sediments.

Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyeletrolyte pectates (PEC) as a water-soluble natural polymer polysaccharide has been studied using both gasometric and weight loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. The inhibition action of PEC on Al metal surface was found to obey the Freundlich isotherm. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the kinetic results is discussed in the paper.

We have determined the phase transition for the Co-20 and -30 at.% Cu alloys fabricated by arc melting technique, from the binodal to the two phases þL as well as the peritectic transitions, using differential thermal analysis (DTA). We equally studied the effects of aging treatment, ranging from 3 to 35 h, on the alloy samples using scanning electron microscopy (SEM) and Vickers hardness (HV). The activation energies of these alloys are equally determined using five established models. Our results show that for aging time up to 15 h, within the spinodal region at 773 K, the hardness value for Co-20 and -30 at.% Cu alloys oscillates reaching a local maximum at the aging time of 8.50.5 h. After 20 h of heat treatment, the HV for Co-20 at.% Cu alloy diminishes significantly while that of Co-30 at.% Cu effectively stabilizes at 241 MPa. The activation energies for the peritectic transformation based on Ozawa model are estimated to be 2465 and 2680 kJ mol1 for Co-20 and -30 at.% Cu, respectively.

The transmission and reflection spectra of the chalcogenide Te67.5 Ga2.5 As30 thin film with thickness of 150, 300 and 450 nm are measured. The formed crystalline phases due to the thermal annealing of the as-prepared film are identified by X-ray diffraction. The as-prepared films have absorption mechanism which is an indirect allowed transition with a decrease in the value of the optical energy gap (Eg) as the thickness increases. The films annealed at temperatures higher than the temperature of the onset of the crystallization have a direct allowed transition with an increase in Eg with annealing temperatures. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied.

The transmission and reflection spectra of the chalcogenide Te67.5 Ga2.5 As30 thin film with thickness of 150, 300 and 450 nm are measured. The formed crystalline phases due to the thermal annealing of the as-prepared film are identified by X-ray diffraction. The as-prepared films have absorption mechanism which is an indirect allowed transition with a decrease in the value of the optical energy gap (Eg) as the thickness increases. The films annealed at temperatures higher than the temperature of the onset of the crystallization have a direct allowed transition with an increase in Eg with annealing temperatures. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied.

Porous alumina films, prepared by anodization of pure aluminum (Al) thin film deposited on SiO2/Si substrate, has been fabricated and characterized. Constant voltage and constant current anodization in two-electrode cell configurations were performed. Electro-oxidation of Al in the voltage range of 1-90V was explored using the three electrolytes: 1M sulfuric acid (1-22V), 0.3M oxalic acid (1-70V) and 0.75M phosphoric acid (60-90V). The temperature dependence of the i-V characteristics and the properties of the porous structures are ascertained. An explanation for the difference in current density at same voltage for different electrolytes. The kinetics and mechanistic aspects of Al anodization are discussed.