Protection Glass Eyewear Against a YAG Laser Based on a Bandpass Absorption Filter

In this article, copper zinc phosphate glass doped with 5 % barium oxide has an amazing optical property due to its application as bandpass filters. Typically, the glass conventional casting with chemical composition 42P₂O₅–(14- x)Na₂O–39ZnO–5BaO–xCu₂O where (x = 2, 4, 6, 8 and 10) was formed. The density was measured using the conventional Archimedes method and the molar volume was calculated. The change of glass structure was investigated using X-ray diffraction analysis (XRD). Distinctly, the results revealed that no crystal growth in all glass systems was observed. The density of glass samples was increased whereas the molar volume was decreased with increasing copper content. The absorption, transmission and reflection were measured and some other optical properties were calculated like UV cut-off, and IR cut-off. For instance, the visible cut-off started from 462 to 532 nm while the IR bonds were initiated at 630 to 1200 nm with 6 to 10 % Cu₂O concentration.     

Effect of Sodium Carbonate on the Cloud Point in Alkyl Ether/Brine Systems: Apparent Relation with Dynamic Interfacial Tension Minimum

The effect of Na₂CO₃ on the cloud point in Na₂CO₃/surfactant/brine was investigated using two series of nonionic surfactants, C₁₃EO _x and C₁₇EO _x . The cloud point, T _cp, was found to decrease linearly with increasing Na₂CO₃ concentration. This was attributed to Na⁺ and particularly to CO₃ ^2?salting-out effect. The slope a = dTcp/d[Na₂CO₃] became more and more negative as the degree of ethoxylation is increased, suggesting that the higher the number of ethylene oxide (EO) groups the stronger is the cloud point depression for a given increment in Na⁺and CO₃ ^2?ions in solution. This was also illustrated by the linear variation of ΔT _cp = T _cp,0 ? T _cp,[Na2CO3] with the surfactant degree of ethoxylation.     

EPR and optical studies on binary mixed alkali-alkaline earth oxide borate glasses doped with Cu<Superscript>2+</Superscript> ions

Mixed alkali alkaline earth oxide borate glasses of the composition (25 – x)Li₂O–xK₂O–12.5BaO–12.5MgO–49B₂O₃–1CuO (x = 0, 5, 10, 15 and 20 mol %) were prepared by the melt quenching technique. The X-ray diffractograms of all the glass samples were recorded at room temperature. Peak free X-ray spectra revealed the amorphous nature of all the prepared glasses. Modulated differential scanning calorimetry (MDSC) was used to determine the glass-transition temperature (T _g ). The probable mixed alkali effect was investigated using experimental techniques like density, molar volume, MDSC, electron paramagnetic resonance (EPR), and optical absorption studies. From the EPR spectra the spin-Hamiltonian parameters were evaluated. The spin-Hamiltonian parameter values indicated that the ground state of \(C{u^{2 + }}is{\kern 1pt} {d_{{x^2} - {y^2}}}\) orbital (²B_1g) and the site symmetry around Cu² is tetragonally distorted octahedral. The variation of g _|| and A _|| as a function of Li₂O content was found to be nonlinear. A broad optical absorption band was observed in all the glasses containing Cu² ions corresponding to ²B_1g → ²B_2g transition. From the optical absorption studies the values of the optical band gap (E _opt) for indirect, direct transitions and Urbarch energy (ΔE) have been evaluated. By co-relating the EPR and optical absorption data, bonding parameters α², β² and β ₁ ² were evaluated.     

Physical Properties,Optical band gaps and Radiation Shielding Parameters Exploration for Dy<Superscript>3+</Superscript>-doped Alkali/Mixed Alkali Multicomponent Borate Glasses

Six compositions of 1 mol % Dy³⁺-doped multicomponent borate glasses containing single Li₂O, Na₂O, K₂O and mixed Li₂O–Na₂O, Li₂O–K₂O, and Na₂O–K₂O oxides have been synthesized by well-known melt-quenching technique. Following the measured density and refractive index values, various physical parameters were estimated for all the glass samples and differences in them are correlated with structural changes. To explore optical properties like absorption edge (λ_cut-off), optical band gap energy (E_opt), and Urbach energy (ΔE), optical absorption spectra were recorded for all the glasses. The E_g has been calculated using Davis and Mott theory for direct allowed, and indirect allowed transitions and the results were reported. The E_g values are also estimated using absorption spectrum fitting (ASF) method. The optical parameters variations have also been associated with the structural changes occurring in the glasses with different alkali/mixed alkali oxides content presence. The shielding properties of the prepared glasses were studied in terms of effective atomic numbers (Z_eff), mean free path (MFP), half value layer (HVL) and macroscopic effective removal cross-section (Σ_R). From these results, it was found that Potassium (K) glass shows superior gamma ray shielding properties due to a higher value of Z_eff and lower values of both MFP and HVL. These results indicate that the prepared glasses might be utilized in place of some common shielding materials to shield γ-rays and neutrons.     

Structure-Property Relations in Barium Borate Glasses from Raman Scattering Data

Glasses in the xBaO-(100 ? x)B₂O₃ system (x = 16–50 mol %) are investigated by Raman spectroscopy. The spectral forms of stoichiometric groupings are separated from the experimental Raman spectra. The diagram of the content of these groupings in glasses is constructed. The diagram obtained makes it possible to calculate the densities, refractive indices, temperature coefficients of linear expansion, and fractions of four-fold-coordinated boron atoms with the use of the experimentally determined partial properties of the groupings. It is revealed that the dependences of the boson peak intensity, the boson peak frequency, and the glass transition temperature on the composition of glasses in the barium borate system correlate with each other.     

Monte Carlo Design and Experiments on the Neutron Shielding Performances of B<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZnO–Bi<Subscript>2</Subscript>O<Subscript>3</Subscript> Glass System

Neutron shielding properties of (90 – x)B₂O₃–10ZnO–xBi₂O₃ glass systems (where x = 15, 20, 25 and 30 mol %) were investigated by Monte Carlo simulations (FLUKA and GEANT4) and experiments. Neutron mass removal cross sections, number of inelastic scattering, elastic scattering, and capture interactions were estimated by simulations. ²⁴¹Am/Be neutron source was used for the neutron equivalent dose rate measurements. As a result, produced glass samples have fine neutron shielding capacity.     

Synthesis of fluorozirconate ZBNL glass with partial or complete substitution of europium difluoride for barium (lanthanum) fluorides

The vitrification in two sets of fluorozirconate glass 53.5ZrF₄ · 20NaF · 20BaF₂ · (6.5 ? x)LaF₃ · xEuF₂ (0 ≤ x ≤ 6.5 mol %) (I) and 53.5ZrF₄ · 20NaF · (20 ? x)BaF₂ · 6.5LaF₃ · xEuF₂ (0 ≤ x ≤ 20 mol %) (II) has been studied. It has been determined that, in set I, at full or partial replacement of lanthanum fluoride by europium difluoride (1–6.5 mol %), colorless transparent glass is formed. In the samples of set II, at the substitution of BaF₂ in order to obtain stable glass under analogous conditions, the initial batch should not contain more than 7.0 mol % EuF₂. The methods of differential-thermal and X-ray phase analyses and IR and electron spectroscopy were used to study the properties and phase composition of the obtained glass and vitrocrystalline materials. Using the Grubi criterion, the optimal, with respect to crystallization, EuF₂ content has been deter-mined in the glass of both systems. In the devitrified glass of series II, the low-temperature modification of compound EuZrF₆ is formed, in addition to sodium, barium, and lanthanum fluorozirconates. For the vitro-crystalline samples, the absorption bands of Eu-F bonds are observed in infrared spectra, in addition to the broad band (～500 cm^?1), which is intrinsic for all fluorozirconate glass. The electron diffuse reflection spectra confirm the presence of both double and triple-charged europium ions in glass.     

Parameters of luminescence and the local structure of Eu<Superscript>3+</Superscript> centers in fluorogermanate glasses

The influence of the chemical nature of the local environment of Eu³⁺ ions on the parameters of luminescence of these centers in glasses of the (BaGeO₃)_{1 ? x ? y} (Al₂O₃) _x (0.45CaF₂ · 0.55MgF₂) _y (x = 0.25, y = 0; x = 0.17, y = 0.17; x = 0.15, y = 0.22; x = 0.07, y = 37.00; x = 0, y = 0.45) system is investigated. The oxidation state of europium atoms and the degree of homogeneity of their local environment in the glasses are determined using ¹⁵¹Eu Mössbauer spectroscopy.     

SHS of Y<Subscript>2</Subscript>Ti<Subscript>2</Subscript>O<Subscript>7</Subscript>-based mineral-like ceramics: Influence of green density

Explored was the influence of compacting pressure (P) and green density (ρ) on the properties of Zr-doped mineral-like pyrochlore ceramics Y₂(Ti_{1 – x} Zr _x )₂O₇ (x ≤ 0.3) prepared by SHS method. The optimal ρ values that provide minimal porosity and maximal mechanical strength of synthesized ceramics were found. An increase in ρ was found to decrease combustion temperature and increase pyrochlore lattice parameter a. Green density was also found to affect phase composition of the SHS-produced ceramics under study.     

Photon interaction parameters for some ZnO–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>–P<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

Some photon interaction parameters such as mass attenuation coefficient, effective atomic number, half value layer, mean free path and electron density for 15ZnO–(17.5–x)Al₂O₃–xFe₂O₃–67.5P₂O₅ glass system (x = 0, 7.5, 12.5, 17.5) and 15ZnO–(25–x)Al₂O₃–xFe₂O₃–60P₂O₅ glass system (x = 0, 25) have been investigated in the photon energy range of 1 keV to 100 GeV. It has been observed that all the photon interaction parameters for the selected glass systems vary with the photon energy. Among the selected glass systems, the sample 15ZnO–25Fe₂O₃–60P₂O₅ glass system shows maximum values for mass attenuation coefficients, effective atomic numbers, electron densities and minimum values for mean free path and half value layer in the entire energy grid.     

Raman spectra and surface structure of CaO-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-SiO<Subscript>2</Subscript> glass leached in potassium hydroxide solutions

It is difficult to research on the surface structure of amorphous phase in fly ash during leaching reaction due to crystalline phase and complex structure. In the present work, in order to reveal the effects of leaching reaction on the surface structure of amorphous phase in fly ash, the modelling CaO-Fe₂O₃-Al₂O₃-SiO₂ glass was prepared by the traditional melting methods. The leaching reaction of CaO-Fe₂O₃-Al₂O₃-SiO₂ glass with 7.5 M KOH was investigated by spectroscopy, spectrophotometer and wet chemical method. The results show that the content of Q ¹, Q ², Q ³ and Q ⁴ of glass without corrosion was 4.21, 9.51, 23.03 and 52.55%, respectively, which shows that the network polymerization of glass is compact. The leaching reaction of glass can be described by the following equation: dS/dt = k/(r + S ₀). Leaching in KOH for various times induces the content of Q ⁴ and Q ¹ to be decreased, and Q ² and Q ³ increased, resulted in the depolymerization of network and the surface glass dissolved in alkaline solution to form a gel phase. In stage one of leaching reaction, the rate of iron ion leached from glass surface was slow, which resulted in the small slope of straight-line relationship of leaching curve. In the following stage, the leaching rate of iron ion increased with the prolongation of time.     

Sol-Gel Synthesis,Thermal Behavior of Nanopowders and Chemical Stability of La<Subscript>1 – <Emphasis Type="Italic">x</Emphasis></Subscript>Ho<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>PO<Subscript>4</Subscript> Ceramic Matrices

Nanosized powders of orthophosphates in the LaPO₄–HoPO₄–H₂O system have been synthesized to determine the mutual solubility of LaPO₄ · nH₂O and HoPO₄ · nH₂O initial components and to obtain ceramic matrices by sintering them. Formation of hexagonal, monoclinic or tetragonal solid solutions was revealed, and their limits and thermal stability were determined. A series of limited hexagonal LaPO₄ · nH₂O-based solid solutions was observed within the 0 ≤ x ≤ 0.6 concentration range up to 600°C. Further they transformed to monoclinic LaPO₄-based form within the 0 ≤ x ≤ 0.3 concentration range. Solubility of LaPO₄ · nH₂O and LaPO₄ in tetragonal HoPO₄(· nH₂O) is lower (≤10 mol %). Specific surface area of La_1–xHo_xPO₄ · nH₂O powders was in the range of 90.5–165.0 m²/g depending on x. Leaching rate of La³⁺ and Ho³⁺ from La_1–xHo_xPO₄ matrices in nitric acid solution (pH 1–2) was determined to be 10^–5–10^–2 g/(cm² day) for both ions.     

Problems of compatibility of the values of glass transition temperatures published in the world literature

The influence of different factors (primarily, the temperature-time conditions for preparation and measurement of samples) on the glass transition temperatures determined from the temperature dependences of properties is analyzed using the calculations performed in terms of the relaxation theory of glass transition. The most optimum conditions for measurement of the glass transition temperatures T _g that ensure the compatibility of the values of T _g obtained by different researchers are recommended. The validity of the assertion that the glass transition temperature T _g is a temperature at which the viscosity of glasses is equal to 10¹³ P is considered.     

Optical,Spectral, and Radiation-Shielding Properties of High-Lead Phosphate Glasses

The spectral, optical, physicochemical, radiative, and radiation-shielding properties of glasses in the PbO-P₂O₅-R _m O _n system (where R _m O _n stands for Group I–V element oxides) are investigated as a function of their composition. The composition of a colorless radiation-resistant high-lead glass suitable for production on a semicommercial scale is determined. The properties and optical quality parameters of the glass are studied. The new phosphate glass is a lead metaphosphate containing aluminum, alkali, and alkaline-earth oxides. This glass is resistant to radiation at doses up to 10⁷ R and has an optical transmission edge at 360 nm. The coefficient of absorption of gamma radiation for the new glass is larger than those of dense silicate flints. According to the optical parameters, the new glass lies between dense flints and dense barium flints in the Abbe diagram and compensates for the absence of the latter flints in catalogues of radiation-resistant glasses.     

Effect of iron oxide (Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>) on the structural,optical, electrical,and dielectric properties of SrO–V<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

The oxide glass system of the composition (10 – x)SrO–xFe₂O₃–90V₂O₅, (x = 0, 2, 4, 6 and 8 mol %) were prepared by a standard melt quenching technique. The amorphous nature of the prepared glass was confirmed using X-ray diffraction technique. The infrared spectra of these glasses were recorded over a continuous spectral range (850–1500 cm^–1). The density of prepared sample was obtained by the Archimedes principle. The physical parameters of the glasses were also determined with respect to the composition. Density increases from 3.10 to 3.20 g/cm³, whereas the molar volume decreases with the increase in Fe₂O₃ concentration. In order to study optical properties, absorption spectra were measured at room temperature. Indirect optical energy band gap, optical dielectric constant, refractive index were calculated from optical energy band gap. The refractive index decreases gradually with the increase in Fe₂O₃ content due to increase of bridging oxygen’s. For temperatures from 300 to 500 K, the dc conductivity increased with the increasing Fe₂O₃ content. The dielectric properties like dielectric constant, dielectric loss factor and dielectric loss tangent investigated at the room temperature in the frequency range of 10 kHz to 1 MHz decreases with frequency. The dielectric behavior shows strong frequency as well as composition dependence.     

Excess volume and excess enthalpy of binary mixtures composed of 1,2-dichloropropane and 1-alkanol (C5-C8)

The excess molar volumes and excess molar enthalpies at T=298.15 K and atmospheric pressure for the binary systems {CH₃CHClCH₂Cl (1)+CH₃(CH₂) _n?1OH (2)} (n=5 to 8) have been determined over the whole range of composition from the density and heat flux measurements using a digital vibrating-tube densimeter and an isothermal calorimeter, respectively. The measured excess molar volumes of all binary mixtures showed positive symmetrical trend with values increasing with chain length of 1-alkanol. Similarly, excess enthalpy values of all binary mixtures showed skewed endothermic behavior with values increasing with chain length of 1-alkanol. The maxima of excess molar enthalpy values were observed around x₁=0.65 with excess enthalpy value ranging from 1,356.8 J/mol (1-pentanol) to 1,543.4 J/mol (1-octanol). The experimental results of both H _m ^E and V _m ^E are fitted to a modified version of Redlich-Kister equation using the Padé approximant to correlate the composition dependence. The experimental H _m ^E data were also fitted to three local-composition models (Wilson, NRTL, and UNIQUAC). The correlation of excess enthalpy data in these binary systems using UNIQUAC model provides the most appropriate results.     

Effect of nitrogen to niobium atomic ratio on superconducting transition temperature of δ-NbN<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> powders

Powders of cubic niobium nitride δ-NbN _x with a particle size of below 20 μm were prepared by reactive diffusion at T = 1455?1475°C under nitrogen pressures of P ₁(N₂) = 0.1?3 MPa and P ₂(N₂) = 25 MPa. For these powders, the values of the stoichiometric coefficient x, lattice parameter a, and the superconducting transition temperature Tc were measured and the a(x), T _c(x) and T _c(a) functions were analyzed. The T _c values were found to linearly grow with increasing a (decreasing structure imperfection). A maximum value of T _c (15.8 K) corresponded to a maximum value of a (4.3934 Å). Maximain the a(x) and T _c(x) curves were found to correspond to a slightly substoichiometric nitride with x = 0.98. Having synthesized cubic niobium nitrides with 0.892 < x < 1.062, we managed to measure the dependences of a and T _c on x all over the almost entire homogeneity range for δ-NbN _x . Our a(x) and T _c(a) functions were found to reasonably agree with those previously reported for SHS-produced δ-NbN _x powders.     

Optical Properties of Silver Halide Photochromic Glasses Doped with Cobalt Oxide

Photochromic glasses having composition (SiO₂)₄₅(B₂ O ₃)₃₅(Al₂O₃)_7.5(Na₂O)_12.5(AgBr), (Cu₂O) doped with (CoO) _x , in which, x = 0, 0.006, 0.02 and 0.07 g were prepared using the conventional melt technique. The amorphous nature of these glass samples was confirmed using X-ray diffraction analysis at room temperature. The absorption measurements in the infrared region of the spectrum were recorded in the wave number range (4000–400) cm^?1. Spectral reflectance and transmittance at normal incidence of the prepared glass samples were recorded with a spectrophotometer in the spectral range 200–2500 nm. Experimental and theoretical densities of the prepared glass samples were measured, calculated and compared. Analytical expressions were used to calculate the real and imaginary parts of the refractive indices. Dispersion parameters such as: single oscillator energy, dispersion energy, average oscillator wavelength, and Abbe’s number were deduced and compared. Absorption dispersion parameters such as: optical energy gap for direct and indirect transitions, Urbach energy and steepness parameter were calculated. Effects of doping with cobalt oxide CoO as a transition metal on linear and predicted nonlinear optical parameters were investigated and interpreted. Experimental results indicate that there is an optimum concentration of cobalt doping around 0.006 g. The optical band gap decreases with increasing doping and causes an increase in nonlinear optical parameters. Doping with cobalt oxide improves the linear and nonlinear optical properties of the prepared glasses.     

Spatial localization of holes in La<Subscript>2 − <Emphasis Type="Italic">x</Emphasis></Subscript>Sr<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>CuO<Subscript>4</Subscript>

The parameters of the tensor of the electric field gradient (EFG) in cation sites of the La_{2 ? x} Sr _x CuO₄ lattice have been determined by the method of emission Mössbauer spectroscopy on ⁵⁷Co(^57m Fe), ⁶⁷Cu(⁶⁷Zn), ⁶⁷Ga(⁶⁷Zn), and ¹⁵⁵Eu(¹⁵⁵Gd) isotopes. There is no quantitative agreement between the calculated (the pointcharge model) and experimental values of the main component of the tensor EFG V _zz , which is explained by the absence of the reliable data on the Sternheimer coefficients for Fe³⁺, Zn²⁺, and Gd³⁺ ions. Based on the comparison of the calculated and experimental dependences of V _zz on x it was shown that the holes appearing during the substitution of La³⁺ for Sr²⁺ are localized preferably on the oxygen atoms that are in the same plane as the copper atoms, which is in agreement with the model discussed in the literature and assumes that the mechanism responsible for the high-temperature superconductivity of solid solutions La_{2 ? x} Sr _x CuO₄ is the interaction between the conductivity electrons and two-atomic two-electron centers with negative correlation energy.     

Structure and Electrical Properties of Iron Borosilicate Glasses

Glassesofnominal composition 25SiO₂- 30Na₂O-2Al₂O₃-x Fe₂O₃-(43- x)B₂O₃ (x = 1 to 6 mol%) were prepared by the ordinary melt quenching technique. The influence of Fe₂O₃ substitution at the expense of B₂O₃ on structure and electrical conductivity of sodium borosilicate glasses was investigated. The conductivity was found to increase with increasing Fe₂O₃ content. A double channel conduction mechanism was introduced to explain the electrical conductivity measurements. Moreover, the activation energy decreases considerably in the temperature range from 473 to 773 °K. The activation energies of conduction in various temperature regions were calculated. The conduction was best described by sodium ion migration and hopping between the two valence states of iron. FTIR absorption spectra in the spectral range 1600-400 cm^?1 were measured and a deconvolution analysis technique (DAT) using Gaussian peaks was introduced to analyze the studied glasses. Different characteristic bands were observed and attributed to different types of borate besides silicate vibrational groups.