Gamma radiation shielding investigations for selected germanate glasses

WOS:000464486000005Radiation shielding characteristics of different germanate glasses with compositions of Nd doped Bi2O3-SiO2/GeO2-Nd2O3, Sm3+ doped B2O3-GeO2-Gd2O3, Tb-3 doped GeO2-B2O3-SiO2-Ga2O3, TeO2-GeO2-Li2O and Na2O-GeO2-P2O5 glasses have been studied using XCOM program at several photon energies between 0.015 and 10 MeV. Dependencies of their photon attenuation properties with the photon energy and the composition have been investigated. The mass attenuation coefficient values and the effective atomic numbers for Nd doped Bi2O3-SiO2/GeO2-Nd(2)O(3)glasses are higher than those of the other samples. 69Bi(2)O(3)-30GeO(2)-1.0Nd(2)O(3) has the highest mass attenuation coefficients among the selected samples. The Z(eff) results revealed that to increase the photon attenuation ability for the germanate glasses, high Z-elements (such as Bi, Te and Tb) in a suitable concentration must be included. The HVL results for the present germanate glasses suggested that the attenuation capacity of the gamma photons increases as the density of the sample increases, hence, the glass sample with high density must be considered for high attenuation ability. Also, the significant influence of modifier contents on the HVL values namely the attenuation ability has been noticed for Tb-3 doped GeO2-B2O3-SiO2-Ga2O3 and TeO2-Li2O-GeO2 glasses. Moreover, the values of the mean free path for the selected samples have been compared with those of different radiation shielding glasses and concrete samples

Bi2O3 B2O3 ZnO BaO Li2O glass system for gamma ray shielding applications

WOS:000506318200006In order to investigate new candidate glasses for gamma shielding application, we synthesized a number of glasses with composition of (50 + x)Bi2O3-(30-x)B2O3-10ZnO-5BaO-5Li(2)O where x = 10, 15 and 20, all in mol%. We used the conventional melt-quenching-annealing technique with melting temperature at 975 degrees C and 300 degrees C for 30 min and 5 h, respectively. Density and other important physical properties have been measured and calculated using related methods and formulas. Moreover, X-ray diffraction have been utilized for all samples to explore the structure of these glasses, the XRD profile have been recorded between 10 degrees to 80 degrees for all samples, while the functional groups of the elements evolved in these glasses have been studied using FTIR with the range of 4000-400 cm(-1). Additionally, optical absorption for the synthesized glasses have been measured in the range of 200-800 nm to investigate the cut-off wavelength and optical band gap. Besides, the mass attenuation coefficient values of the present glasses have been estimated through WinXCom software as well as MCNPX computer code and the obtained results were used to determine the effective atomic number (Z(eff)), the half value layer (HVL) and the mean free path (MFP). From the derived results, it was found that S3 is the superior glass sample in terms of shielding performance on account of larger Z(eff) values and lower MFP/HVL values among the investigated glasses. The present glasses indicate potentiality to be evaluated as shielding absorbers and for an improved shielding effectiveness of the Bi2O3-B2O3-ZnO-BaO-Li2O glasses, a large Bi2O3 concentration would be required

Solar-Light-Driven Ag9 (SiO4)2 NO3 for Efficient Photocatalytic Bactericidal Performance

Photocatalytic materials are being investigated as effective bactericides due to their superior ability to inactivate a broad range of dangerous microbes. In this study, the following two types of bacteria were employed for bactericidal purposes: Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The shape, crystal structure, element percentage, and optical properties of Ag9 (SiO4)2 NO3 were examined after it was successfully synthesized by a standard mixing and grinding processing route. Bactericidal efficiency was recorded at 100% by the following two types of light sources: solar and simulated light, with initial photocatalyst concentration of 2 µg/mL, and 97% and 95% of bactericidal activity in ultra-low photocatalyst concentration of 0.2 µg/mL by solar and simulated light, respectively, after 10 min. The survival rate was studied for 6 min, resulting in 99.8% inhibition at the photocatalyst dose of 2 µg/mL. The mechanism of bactericidal efficiency was found to be that the photocatalyst has high oxidation potential in the valence band. Consequently, holes play a significant part in bactericidal efficiency