Characterisation and modelling of layered discontinuous reservoirs for waterflood predictions

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Study of Gamma Ray Attenuation of High-Density Bismuth Silicate Glass for Shielding Applications

ABSTRACT High density glass samples with a chemical formula of xBi 2 O 3 -30SiO 2 -10B 2 O 3 -20BaO-(40−x)ZnO (where x= 0, 10, 20, 30, and 40 mol %) were prepared using the melt-quenching technique in order to design a new transparently shielding materials for many fields of applications. The amorphous state of the samples was examined using X-ray diffraction technique at room temperature. The effect of bismuth on the structural properties of the studied glasses was characterized through density and its derivative parameters. Before measuring the attenuation capability, the optical transparently for visible light were tested using the transmittance spectra measurements in the UV-Visible region. Optical parameters such as optical band gap, Urbach energy, and refractive index were evaluated from the optical data. The Gamma ray attenuation coefficients of the glass samples were performed at gamma ray energies 238.63, 338.28, 583.19, 911.20, 968.97, 1173.23, 1332.49, and 2614.51 Co radioactive sources. The transmitted gamma rays were detected using Hyper Pure Germanium detector (HPGe) under good geometry conditions. The Linear attenuation coefficients were deduced from the attenuation curves and then the mass attenuation coefficients and the half value layer were estimated. Theoretical mass attenuation coefficients were calculated using WinXCom program (version 3.1). A good correlation was observed between the experimentally determined and those computed theoretically of the mass attenuation coefficients

Structural and spectroscopic analyses of copper doped P2O5 -ZnO-K2O-Bi2O3 glasses

Homogeneous glass samples with different compositions 42 (P2O5)·40 (ZnO)·(16 −x)(K2O)·2 (Bi2O3)·x(Cu2O) (where x = 1, 2 and 3 mol%) were prepared by conventional melt-quenched technique under controlled conditions. The structure of the prepared glass samples was investigated by X-ray diffraction. Optical properties (transmittance and reflectance) of the glasses were measured in the wavelength range 200–900 nm. The optical band gap energy of the investigated glasses with 1, 2 and 3 mol% Cu2O was estimated from absorption data using the Mott and Davis relation and found to be 2.33, 2.45 and 2.53 eV, respectively. The mechanism of optical absorption was found to be direct. The band tail width was also estimated and found to lay in the acceptable range. Refractive index, absorption coefficient, extinction coefficient and real/imaginary parts of dielectric constants were calculated. Further to this, some theoretical investigation of the spectral problems was carried out. The investigation was based on finite difference method

Dielectric and optical properties of CuO containing sodium zinc phosphate glasses

Dielectric and optical properties of 45 P2O5-34 ZnO-(20 −x)Na2O-1 Al2O3-xCuO glasses (0 ≤ x ≤ 5) were investigated. The frequency and composition dependencies of the dielectric parameters were analysed and discussed. The values of real part of dielectric constant (RPDC) lie between 748 to 1169 for RPDCMax, and 654 to 1031 for RPDCMin. The range of values of imaginary part of dielectric constant (IPDC) extends from 39.4 to 57.5 for IPDCMax and from 27.3 to 40.1 for IPDCMin. It was observed that each of these parameters begins to decrease with increasing CuO content, but further addition of CuO causes their rise. Thus, small amount of CuO causes a decrease in both RPDC and IPDC until CuO content reaches 2 mol%, thereafter, they nearly return to their original values at 5 mol% of CuO. Similar behaviour was observed for AC conductivity. Transmittances of the investigated glasses were also measured and used to estimate their optical absorption coefficients and optical band gaps. The optical energy gap is ∼4 eV for the samples with up to 4 mol% CuO, while it is somewhat higher (∼5 eV) for the glass with 5 mol% CuO