Elastic properties of tellurite glasses

Elastic properties of binary and ternary tellurite glass systems of the composition (in mol%) (100-x) TeO2 - x Nb2O5, and (100-x) TeO2 - 0.5x (Nb2O5 + Li2O) were calculated from the measured densities as well as from longitudinal and shear ultrasonic velocities at room temperature. Ultrasonic velocity measurements were taken at 4 MHz ultrasonic frequency using the pulse echo technique. Elastic moduli, and Debye temperature calculated from experimental data and calculated theoretically using the bond compression model were used to obtain quantitative details about the structure of these glasses. The effect of adding either Nb2O5 alone or Nb2O5 and Li2 on the elastic moduli was investigated in terms of the number of network bonds of the glass systems. The average atomic ring size of the network was also calculated and it was found that it depends on the concentration of the modifiers. The obtained results show that these glasses become more stable and compact when modified with Nb2O5 or with Nb2O5 and Li2O, which increases the elastic moduli in the two systems

Alkaline phosphate glasses and synergistic impact of germanium oxide (GeO2) additive: Mechanical and nuclear radiation shielding behaviors

In this study, mechanical and nuclear radiation shielding behaviors of highly efficient alkaline phosphate glasses with various GeO2 concentrations were evaluated for their nuclear radiation shielding applications. Moreover, the glass rigidity parameters of alkaline phosphate glasses were calculated for determination mechanical properties. The mu m values were calculated using XCOM program and MCNPX simulation code. The nuclear radiation shielding properties (gamma and neutron) such as mu m, HVL, TVL, MFP, Z(eff), EBF, EABF, and Sigma(R) were calculated for all alkaline phosphate glasses with various GeO2 concentrations. The results showed that mu m, Z(eff), and Sigma(R) increased as the Bi2O3 concentration increased. The G14 glass sample had the minimum HVL, TVL, MFP, EBF and EABF. The G14 sample had the largest mu m, Z(eff), and the number of network bonds, and can be considered as an excellent attenuator for gamma and neutron shielding. The outcomes of recent investigation can be useful to understand the nature of GeO2 additive into alkaline phosphate glasses, which can be considered as a candidate shield type in medical and industrial radiation facilities

Ultrasonic relaxation of TeWB glasses at low temperatures

The ultrasonic relaxation of tellurite glasses xB2O3 – 70 TeO2 – (30 – x) WO3, 0 ≤ x ≤ 30 mol% was investigated by measuring the ultrasonic attenuation (αL) in these glasses in the thermal range 140–300 K (T) at various frequencies (f). Some characteristics can be obtained from the relation of αL–T, such as the average activation energy (Ep) and the attempt frequency (f0). The variables Ep and f0 are a function of frequency and B2O3 content. Moreover, the relation αL–T accounts well for the oscillations of the oxygen atoms in a relaxation process. Such a physical process is originated from transmitting ultrasonic energy to the oscillating oxygen atoms in a dual-well potential. The relaxation process is inspected by a model named central force one. The subtracted different physical variables from such a model are a function of B2O3 content

Mechanical, physical and gamma ray shielding properties of xPbO-(50-x) MoO3-50V(2)O(5) (25 <= 45 <= mol %) glass system

In this study, five different glasses encoded Pb25, Pb30, Pb35, Pb40 and Pb45 based on xPbO- (50-x) MoO3-50V(2)O(5) (25 <= x <= 45 mol %) glass system were fabricated. MCNPX code, XCOM and XMuDat have been utilized to compute the mass attenuation coefficient (mu(m)) values of the xPbO-(50-x)MoO3-50V(2)O(5) glass system at 0.015-15 MeV photon energies. X-ray diffraction (XRD), was characterized for fabricated glasses. Moreover, different shielding parameters such as Half Value Layer, Tenth Value Layer, relaxation length, effective atomic numbers and effective electron densities, basic gamma-ray attenuation properties such as Exposure Buildup Factors (EBF) and Energy Absorption Buildup Factors (EABF) at different penetration depths, Effective Removal Cross Section against fast neutrons have been calculated. In addition to nuclear radiation shielding parameters, numerous physical and mechanical parameters were determined. The experimental elastic modulus results were compared using the theoretical models Makishima-Mackenzie and Rocherulle model. The values of these moduli have been compared to their experimental values. The results observed that the composition has the highest value of PbO (45 mol. %) showed excellent nuclear radiation shielding and elastic properties

(59.5-x) P2O5-30Na(2)O-10Al(2)O(3)-0.5CoO-xNd(2)O(3)glassy system: an experimental investigation on structural and gamma-ray shielding properties

In this study, five different glasses encoded ND1, ND2, ND3, ND4 and ND5 based on (59.5-x) P2O5-30Na(2)O-10Al(2)O(3)-0.5CoO-xNd(2)O(3)(x = 1, 2, 3, 4 and 5 mol%) glass system were fabricated. Using two gamma- ray energies emitted from point sources, 356 keV (Ba-133) and 662 keV (Cs-137), gamma-ray attenuation coefficients were measured as a function of the Nd(2)O(3)concentration. The theoretical values of the mass attenuation coefficient were calculated using the XCOM program at 0.015-15-MeV photon energies. As it is underlined in the results section, the mass attenuation coefficient increases as the Nd(2)O(3)concentration increases. X-ray diffraction (XRD) was characterized for fabricated glasses. Moreover, different shielding parameters such as half-value layer (HVL), mean free path (MFP), effective atomic numbers (Z(eff)), basic gamma-ray attenuation properties such as exposure buildup factors (EBF) and energy absorption buildup factors (EABF) at different penetration depths were calculated. With increasing Nd(2)O(3)additive in glass samples, half-value layer (HVL), average free path (MFP), exposure and energy absorption buildup factor (EBF and EABF) values decrease. On the other hand,Z(eff)values increase with increasing Nd(2)O(3)additive in glass samples at the photon energy 0.015-15 MeV. The results highlighted that ND5 sample with highest value of Nd2O3(5 mol%) showed excellent nuclear radiation shielding properties