We report here the effects of argon heat treatment at 450 ◦C for 12 h on two similar sets of oxygenated Y1 − xCax:123 superconducting samples prepared by two different heat treatments and oxygen purity as reported bySedky and Abu-Ziad (Physica C 470, 659; 2010). The oxygenatedsamples are called ssqHp, sssHp, ssqLp, and sssLp,and the Ar annealed samples are called ssqHpAr, sssHpAr,ssqLpAr, and sssLpAr. It is found that the c parameterof annealed samples is gradually increased with Ca additionfor all samples, while orthorhombic distortion (OD) is decreased. It is also noted that Ar heat treatment decreased the link between superconducting grains for all samples, and a linear decrease in microhardness (Vickers hardness number (VHN)) with Ca addition is obtained. But the rate of increase/decrease of the c parameter, OD, and VHN againstCa content is different in ssqHpAr and sssLpAr samples ascompared to sssHpAr and ssqLpAr samples. Interestingly, the sssHpAr and ssqLpAr samples show a considerable loss of oxygen and small decrease in Tc. While the ssqHpAr and sssLpAr samples show much smaller loss of oxygen and a gradual increase in Tc up to 16 and 17 K, respectively. Theseresults are discussed in terms of the mechanism of oxygen loss by Ca in addition to ssqHpAr and sssLpAr samples as compared to sssHpAr and ssqLpAr samples.

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We report here the fluctuation-induced excess conductivity in RBaSrCu3O7-δ (R=Y, Gd, Nd, and La) superconductor. It is found that Y and Gd samples are orthorhombic, while the Nd and La samples are quasi-tetragonal. The oxygen content is found to be close to 7 for all R:1113 samples. The logarithmic plots of Δσ and reduced temperature Є reveal two different exponents corresponding to crossover temperature due to shifting the order parameter from (2D/1D) to (3D).The critical temperature, mean field temperature, crossover temperature, out of plane coherence length, and interlayer coupling are decreased as the ionic size increases. While the in plane and effective coherence lengths, and anisotropy are increased.We have also estimated several physical parameters such as upper critical magnetic fields in both a-b- and c-axis (Bab and BC), and critical current density J (0 K), and their values are found to be decrease as the ionic size increases. The results are discussed in terms of oxygen rearrangement, localization of carriers, coherence lengths, and anisotropy which are produced as the ionic size increases.

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Seismic hazard in terms of peak ground acceleration and spectral acceleration values, have been computed for the first time in Egypt using both historical and instrumental earthquake data. For this purpose, an updated and unified earthquake catalogue, spanning the time period from 2200 B.C. to 2013, has been prepared for Egypt and its surrounding region. Moreover, new seismic source model includes the seismic activity in and around Egypt, consisting of a total of 88 seismic zones (for shallow- and intermediate-depth seismicity) has been considered in the current assessment. The seismicity parameters (b-value, activity rate, and maximum expected magnitude) have been computed for the delineated seismic sources. Six well-known ground motion prediction equations were selected to model the ground motion attenuation for the different tectonic environments in Egypt. A logic tree design was setup, after a sensitivity analysis, to consider the epistemic uncertainty in the Gutenberg-Richter b-value, maximum possible magnitude, and the selected ground motion prediction equations. Seismic hazard computations, for both rock and stiff soil site conditions, with 39.3%, 10% and 5% probability of exceedance in 50 years (return periods of 100, 475 and 975 years, respectively) were performed. Thus, both PGA values for all the territory and uniform hazard spectra for selected cities among the most important and populated ones in Egypt, were computed and compared with those values considered in the most recent Egyptian building code. From the seismic hazard maps, as well as the uniform hazard spectra, it can be noticed that the maximum hazard values are observed at Nuweiba (Gulf of Aqaba), specifically around the epicentral location of the biggest earthquake event located in Egypt since 1900 until now, the November 22, 1995 (MW 7.2) Gulf of Aqaba earthquake. The PGA values, for rock site, for Nuweiba are 0.16, 0.29 and 0.38 g, and for Cairo are 0.06, 0.13 and 0.18 g, for return periods of 100, 475 and 975 years, respectively. While, the maximum seismic hazard values for Nuweiba and Cairo are observed at natural period of 0.1 sec, which equal to 0.16, 0.74 g and 0.98 g (for Nuweiba), and equal to 0.15, 0.32 and 0.44 g (for Cairo), for return periods of 100, 475 and 975 years, respectively.

Seismic hazard in terms of peak ground acceleration and spectral acceleration values, have been computed for the first time in Egypt using both historical and instrumental earthquake data. For this purpose, an updated and unified earthquake catalogue, spanning the time period from 2200 B.C. to 2013, has been prepared for Egypt and its surrounding region. Moreover, new seismic source model includes the seismic activity in and around Egypt, consisting of a total of 88 seismic zones (for shallow- and intermediate-depth seismicity) has been considered in the current assessment. The seismicity parameters (b-value, activity rate, and maximum expected magnitude) have been computed for the delineated seismic sources. Six well-known ground motion prediction equations were selected to model the ground motion attenuation for the different tectonic environments in Egypt. A logic tree design was setup, after a sensitivity analysis, to consider the epistemic uncertainty in the Gutenberg-Richter b-value, maximum possible magnitude, and the selected ground motion prediction equations. Seismic hazard computations, for both rock and stiff soil site conditions, with 39.3%, 10% and 5% probability of exceedance in 50 years (return periods of 100, 475 and 975 years, respectively) were performed. Thus, both PGA values for all the territory and uniform hazard spectra for selected cities among the most important and populated ones in Egypt, were computed and compared with those values considered in the most recent Egyptian building code. From the seismic hazard maps, as well as the uniform hazard spectra, it can be noticed that the maximum hazard values are observed at Nuweiba (Gulf of Aqaba), specifically around the epicentral location of the biggest earthquake event located in Egypt since 1900 until now, the November 22, 1995 (MW 7.2) Gulf of Aqaba earthquake. The PGA values, for rock site, for Nuweiba are 0.16, 0.29 and 0.38 g, and for Cairo are 0.06, 0.13 and 0.18 g, for return periods of 100, 475 and 975 years, respectively. While, the maximum seismic hazard values for Nuweiba and Cairo are observed at natural period of 0.1 sec, which equal to 0.16, 0.74 g and 0.98 g (for Nuweiba), and equal to 0.15, 0.32 and 0.44 g (for Cairo), for return periods of 100, 475 and 975 years, respectively.