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Vol 45, No 1 (2019)
- Year: 2019
- Articles: 12
- URL: https://journals.rcsi.science/1087-6596/issue/view/13489
Article
Improving the Safety of the Transportation System and Resource Conservation through the Introduction of Environmentally Safe Protective Coatings
Abstract
This paper is devoted to the issues of the application of advanced materials in order to ensure safety and resource conservation in the transportation system. The results of the development and introduction of organosilicate composites for use as anticorrosive, antifouling, antifrosting, and other types of coatings in the transport domain are presented. The chemical mechanisms forming the base of these materials’ fabrication are investigated. The promising prospects of applying organosilicate materials with the aim of resource conservation and reduction of the environmental impact of the transportation industry are demonstrated.
1-9
Influence of Pb Additives on the Kinetics and Mechanism of As2Se3 Glass Crystallization
Abstract
Methods of measuring the density, microhardness, temperature dependence of conductivity, X‑ray analysis, and optical microscopy of the quenched samples are used to explore the kinetics and the mechanism of transformations during the bulk isothermal crystallization of AsSe1.5Рbx semiconducting glasses (х = 0, 0.025, 0.13) in the temperature range 210–340°С. The kinetics of the total bulk crystallization of glasses is analyzed according to the data of density measurements using the Kolmogorov–Avrami equation generalized for the stepwise and incomplete isothermal transformations.
10-18
Nucleation of Crystals in Glass Based on Blast-Furnace Slag: Influence of Chemical Differentiation on the Process of Nucleation
Abstract
Glass compositions based on blast-furnace slag are synthesized. Segregation (chemical differentiation) is observed in one of the glass samples based on blast-furnace slag and its influence on the nucleation of crystals in this glass composition is studied. It is found that the dependences of the crystal growth rate of melilite on the thermal processing time are oscillatory in nature with a monotonic decrease in the absolute oscillation amplitude. The crystallization behavior of glass samples without chemical differentiation is compared with that of glass, in which the process of chemical differentiation precedes the bulk nucleation of crystals.
19-28
Spectral Analysis of Ho3+ Doped Barium Zinc Boro-Tellurite Glasses for Yellow-Green Luminescent Applications
Abstract
In this work, glasses of composition (30 – x)TeO2–30B2O3–10ZnO–30BaO–xHo2O3x = 0.00 0.05, 0.10, 0.50, 1.00, 1.50 mol % have been prepared through the melt quenching method. In order to characterize and explore their structural properties, we measured the density, refractive index of the glass which shows increasing trend with increase in Ho2O3 concentration also FTIR and XRD spectrum is used to study the structural properties of the developed glasses. XRD shows amorphous structure of the prepared glasses. FTIR shows B–O stretching (BO)3– units and Symmetrical stretching vibration of Te–O in TeO3. The electronic states belonging to the 4f configuration of trivalent Ho3+ were determined from the absorption spectra. Judd–Ofelt (JO) intensity analysis had been performed for oscillator strength and JO parameters were estimated to be Ω2 > Ω6 > Ω4. The emission spectra of the Ho doped glass samples were monitored at λexi = 454 nm. In the PL spectra, the characteristic emission bands due to f–f transition of Ho3+ were confirmed for the glass system, the transition 5I8 → 5G6 of Ho3+ ion is a hypersensitive transition and hence host dependent. For the transition 5F4 → 5I8 stimulated emission cross section is found to be 1.79 × 10–22 cm2.
29-35
The Composition, Structure, and Helium Permeability of Glass-Crystalline Shells of Cenospheres
Abstract
The results of studying the relationship of the composition, structure, and the diffusive properties of glass-crystalline shells of cenospheres relative to helium are presented in a wide range of variations of macrocomponent and phase compositions, wt %: 58–68 of SiO2, 21–37 of Al2O3, 30–93 of glass phase, 1–50 of mullite, 0–15 of cristobalite, 1–7 of quartz, and 0–2 of anorthite. It is found that the helium permeability coefficients of the cenosphere glass phase exceed the similar values of silicate glass. The high level of permeability of cenosphere glass-crystalline shells ensures significant potential for their application as membrane elements of the diffusion–sorption technology of the selective recovery of helium from gas mixtures.
36-46
Glass of the Silver Borate xAg2O ⋅ (1 – x)B2O3 System where x = 0.5–47 mol %: Synthesis, Analysis, and Properties
Abstract
Glass of the хAg2O ⋅ (1 – х)B2O3 silver borate system (x = 0.5–47 mol %) is obtained under different conditions. According to the chemical analysis, the composition of the glass changes during the synthesis relative to the calculated one. It is shown that when the synthesis temperature is 850°C and the time is 90 min the relative decrease in the Ag2O content is 3–5% at an Ag2O concentration in the range of 5 to 30%. In this regime of synthesis, the losses are minimal where the Ag2O content ranges from 20 to 30 mol %. When the synthesis temperature is 1050°C and the time of synthesis is 60 min, the relative losses sharply increase with the growth of the Ag2O content from 30 to 47%. Increasing the synthesis temperature results in a significant growth of the relative losses. The glass forming region of the silver-borate system is expanded.
47-52
Impact of Adsorbed Gases on the Transport Mechanisms in Ge8As2Te13S3 Amorphous Films
Abstract
It is shown that the gas adsorption in chalcogenide glasses results in modifications of transport mechanisms by the surface, along with formation of surface localized states. A detailed quantitative analysis is made on experimental data taking on glassy thin films of Ge8As2Te13S3, physically grown in vacuum. The measurements of alternating current (AC) conductivity of these films have been carried out in the frequency range from 5 Hz to 13 MHz, in both dry air and its mixture with a controlled concentration of nitrogen dioxide, at different temperatures. It was found that the changes of environmental conditions by applying of even very small (ppm) amounts of toxic gases, e.g. NO2, dramatically influences the AC conductivity spectra. This is due to a sharp increasing of holes concentration in the valence band of an ultrathin layer adjacent to surface, which results in modification of the dominant mechanism of current flow. In a definite frequency range the charge transport by hopping via valence band edge localized states becomes negligible and the mechanism of conductivity via extended states becomes the main until frequencies ω > 105 Hz, at which the mechanism of hopping via localized states in the vicinity of Fermi level becomes predominant.
53-59
Influence of the Methods of Preparing a Silicate-Sodium Mixture on the Formation of the Structure of Foam Glass Ceramics
Abstract
The fabrication of foam glass ceramics based on diatomite and sodium hydroxide is investigated. The properties of the material depending on the methods of impact on a mixture of components prior to annealing are examined (from the sample heating rate to the annealing temperature). The application of autoclave treatment results in the material’s average density decreasing by a factor of 1.7. A regularity is established regarding the change in the mixture of the silicate module depending on the type of the impact exerted on it. The samples of foam glass ceramics with the average density of 0.45 to 0.75 g/cm3 and a compression strength of 3.4 to 15.1 MPa are fabricated.
60-65
Synthesis and Study of Nanocomposites Based on Beta Zeolite and Magnetite for Targeted Drug Delivery
Abstract
Magnetic nanocomposites based on Beta zeolites and magnetite nanoparticles modified with polydiallyldimethylammonium chloride are synthesized under hydrothermal conditions. Particles of an average size of 100–200 nm characterized with magnetic moments and a high sorption capacity towards the model drug, thiamine hydrochloride (vitamin B1), are obtained. The characteristics of the developed magnetic nanocomposites enable us to consider them as promising materials serving as a base for the development of targeted drug delivery systems.
66-73
New Luminescent BaBi2 – xEuxB2O7 Glassmaterials
Abstract
Bi-containing glasses BaBi2 – xEuxB2O7 (x = 0.00, 0.05, 0.10, 0.20, 0.30, 0.40, 0.50) doped with Eu3+ is obtained. The dependence of the integral intensity of the luminescence on the Eu3+ concentration is revealed. The luminescence quenching starts at the Eu3+ concentrations above 0.20. Other conditions being equal, the maximum luminescence intensity is observed in the BaBi1.5Eu0.5B2O7 specimen. It is shown that the local environment of Eu3+ ions does not depend on the Eu3+ ion content in the studied concentration range.
74-78
Effect of Adding Phosphorus-Containing Surfactants on the Properties of Organosilicon Compositions
Abstract
We report the results of studying the effect of phosphorus-containing compounds, tetraethyl-diamino-tert-butyl phosphite and diethyl phosphite, on organosilicon compositions based on polyphenylsiloxane resin. The addition of these compounds in the composition improves the dispersion of aluminum dust, wettability of the aluminum/steel substrates by the organosilicon composition, and the gloss and surface roughness of the coatings. In the compositions with the maximum disaggregation factor of the pigment particles, the gloss is enhanced by 5% and the coating roughness is decreased by 40%.
79-81
Short Communications
Glass Enamel Monolayer Coating for the Protection of Steel Articles Against Corrosion
Abstract
The composition, structure, properties, and efficiency of a glass enamel coating for the protection of steel articles against corrosion are investigated. The composition of the glass enamel coating with a high adhesion index and chemical resistance towards aggressive media is developed and recommended for industrial implementation in manufacturing enameled steel articles.
82-84