Key Engineering Materials Vols. 675-676

Abstract: Melt quenching technique have been used to prepare the dysprosium-doped lithium-gadolinium borate glasses, which have the composition [60Li₂O:10Gd₂O₃:(30-x) B₂O₃:xDy₂O₃] (LGBO:Dy³⁺), under atmospheric pressure. Some properties: density, molar volume, absorption spectra and photoluminescence of the LGBO:Dy³⁺ glasses were investigated and discussed. The density of glasses drops to the minimum point at 0.05 mol% and swings after that point. The molar volume of the glasses does not depend on Dy₂O₃ concentration. In absorption spectra for the range of visible to near infrared wavelengths, there are 5 obvious peaks indicating the Dy³⁺ in glass network. The intensity of each peak at certain wavelength increases with concentration of the Dy₂O₃. Whereas the excitation spectra show 7 obvious peaks representing the transitions from the ground state ⁶H_15/2 to various excited states. The Xenon compact arc lamps were used to measure the emission spectra with 388 nm light. As the result, the LGBO:Dy³⁺ glass sample with 0.50 mol% of Dy³⁺ shows the highest intensity in the emission spectra.

Abstract: Eu³⁺-doped fluorophosphate (PKACaLF: P₂O₅ – K₂O – Al₂O₃ – CaF₂ – LiF) glasses have been prepared by melt quenching technique. The structural and optical properties have been characterized through Raman, absorption, photoluminescence and decay time measurements. The Judd-Ofelt parameters have been obtained from the absorption spectrum and are found to be Ω₂ = 5.21 x10^-20 cm², Ω₄ = 8.11 x10^-20 cm² and Ω₆ = 1.03 x10^-20 cm². These parameters have been used to calculate the radiative properties of PKACaLFEu10 glass. The relative luminescence intensity ratio of ⁵D₀ → ⁷F₂ to ⁵D₀ → ⁷F₁ transition (R(2/1)) has been evaluated and is found to be 3.25 which indicates moderate asymmetric nature around Eu³⁺ ions. The luminescence decay of ⁵D₀ level exhibit single exponential nature and the lifetimes (~ 2.50 ms) are found to be almost constant with increasing Eu³⁺ ion concentration. The chromaticity color coordinates (x = 0.63, y = 0.31) are in the reddish orange region. From these results, it is confirmed that the present PKACaLF glasses are useful for the development of optical display devices.

Abstract: The present paper reports the structural (XRD and FTIR spectra), physical (like density, molar volume, refractive index etc.), optical absorption and emission properties of Nd³⁺ doped sodium lead zinc lithium borate glass. The glasses with chemical formula (65-x)B₂O₃-15Na₂O-10PbO-5ZnO-5Li₂O-xNd₂O₃ (where x = 0, 0.05, 0.1, 0.5, 1.0, 2.0 and 4.0) have been prepared using the melt-quenching method. XRD characterization shows that the glasses are amorphous nature. The values of measured absorption transitions obtained ten transitions and the hypersensitive transition at ⁴I_9/2 → ²G_7/2+⁴G_5/2. To excite photon from ground state to upper state, used two different wavelength spectra at 582 and 804 nm. The maximum emission intensity of the ⁴F_3/2 → ⁴I_11/2 transition obtained when Nd³⁺ ion content in the borate glass is 1.0 mol %. It is indicating that Nd³⁺ doped borate glass have self-quenching or concentration quenching.

Abstract: A glass system with chemical formula xB₂O₃:20Bi₂O₃:(100-x) Al₂O₃ (x = 55, 60, 65, 70, 75 and 80 mol%) is prepared by melt quenching technique and were investigated the physical and neutron shielding properties. The physical properties were investigated by density, molar volume and discussed with different Al₂O₃ contents. The neutron shielding property was investigated by Monte Carlo techniques (FLUKA and GEANT4 codes) and neutron equivalent dose rate measurements. As a result, neutron shielding capacity of glass samples decrease with increased Al₂O₃ content, so increased B₂O₃ content is a result of positive effects on neutron shielding.

Abstract: This report presents the luminescence and scintillation response of Ce³⁺-doped oxide glasses with high Gd₂O₃ (30 mol%) content. The characteristic emission of Ce³⁺ 5d → 4f transition peaking around 380 nm was observed in its luminescence spectra under UV and X-ray excitation. Photoluminescence decay kinetics was governed by a few tens of nanoseconds decay time. The integral scintillation efficiency of about 22% of that of the Bi₄Ge₃O₁₂ scintillator was obtained under X-ray irradiation. The light yield and its dependence on the integration time were measured and compared with that of the Bi₄Ge₃O₁₂ crystal. The total mass attenuation coefficient at 662 keV γ-rays was also determined and compared with the theoretical one calculated using the WinXCom program.

Abstract: The mass attenuation coefficients and partial interactions of BaO-ZnO-B₂O₃ glasses have been investigated using WinXCom program at difference photon energy. BaO-ZnO-B₂O₃ glasses were prepared in composition xBaO: 20ZnO: (80-x)B₂O₃ (where x = 15 and 20 mol %) by melt quenching technique under normal atmosphere. The densities of glasses are 3.0052 and 3.1022 g/cm³, respectively. The mass attenuation coefficients at 20% mol are higher than 15% mol of BaO in all energy range. The optical spectra were measured and good transparent behavior was obtained. Half value layer (HVL) of glasses are also report and compared with same standard shielding materials and show better shielding than ordinary concrete.

Abstract: The Bi₂O₃ doped with soda lime borosilicate glasses in composition xBi₂O₃ : 15Na₂O : 10CaO : 20B₂O₃ : (55-x)SiO₂ at different concentrations (x = 0, 5, 10, 15, 20, 25 mol%) were studied the photon interactions. The total mass attenuation coefficient, coherent, incoherent, photoelectric absorption and pair production of prepared were studies using WinXcom Program at 1keV to 2MeV. The result of total mass attenuation coefficient and photoelectric absorption were decreases but discontinue because of photoelectric absorption edge at low energy. The photoelectric effect shows the main interaction at the low energy and decrease with increasing of photon energy. The higher photon energy the incoherent scattering found to be the main interaction. But at the photon energy 1.022 MeV, the pair production will be occurs and found to be the main interaction at the photon energy higher than 1.022 MeV.

Abstract: In this work, the well-known program WinXCom have been performed over 1 keV to 20 MeV to obtain the radiation properties (in case of theoretical calculation) of calcium-silico-borate glass system containing Lu₂O₃ in the composition of xLu₂O₃ : 10.0CaO : 10.0SiO₂ : (80.0-x)B₂O₃ with x are Lu₂O₃ concentrations varying from 0.0, 5.0, 10.0, 15.0, 20.0, and 25.0 mol%. The total mass attenuation and partial attenuation coefficients have been studied as functions of chemical compositions and incoming photon energies. In addition, the obtained data were then used to compute the effective atomic numbers and effective electron densities. The calculated results show the variation of both parameters with photon energy.

Abstract: The aim of this work was to study the adsorption efficiency of chitosan as an adsorbent for triclosan, commercially known as Irgasan, in aqueous solutions. The effects of contact time, pH and temperature were investigated using a batch adsorption technique. Langmuir and Freundlich isotherms were used to analyze the equilibrium data at different absorption conditions. The results showed that the maximum adsorption capacity for chitosan was found in the acidic pH 3 and at a temperature of 65 oC. These results suggested that chitosan can be used as an adsorbent for removal of triclosan from aqueous solutions.

Abstract: In this study, Chitosan (CS), Silk Fibroin (SF), and Hydroxyapatite (HA) were selected for scaffold fabrication. The scaffolds were fabricated by freeze drying technique to produce a porous structure. Silk cocoons and bovine bone were used to synthesize the SF and HA, respectively. While CS was produced from commercialized product made from squid pen. The CS was selected as a main structure of the scaffold which was fixed at 50% by weight ratio of the specimen. Another fifty percent are the various ratio of HA and SF. The result confirmed the extraction of silk cocoons and bovine bones were acceptable used as HA and SF. The HA and SF ratio that provided the highest porosity percentage was 25:25, while the highest percentage of cells growth in 7 and 21 days was 50:0 ratio. According to MTT-assay results, the scaffolds in every ratio could be used as a tissue engineering structure for cell proliferation as well as cartilage repairing in the future.