This study presents the development and experimental validation of nanomodified cement obtained by joint grinding of clinker, gypsum, microsilica, polycarboxylate superplasticizer, and dune sand. The optimal composition and technological parameters providing increased strength and performance properties of the binder were studied. A series of cement systems with varying clinker and sand content was prepared, while the amount of gypsum (5 %) and modifier (10 %) remained constant. The results showed that mechanical activation in a ball mill for 110 minutes provided a nanostructured material with a specific surface area of 5500…5700 and an average particle size of 3.5…3.7 ?m. Strength tests have shown that the optimal clinker content is 70...80 %, while replacing up to 20 % of clinker with dune sand does not reduce strength. In this composition, the 28-day compressive strength reached 110…115 МПа, exceeding the control samples by 25…30 %. It was also established that the optimal water-to-cement ratio (W/C = 0.18…0.20) ensures dense microstructure and maximum strength, while higher W/C values lead to increased porosity and strength loss. The findings highlight the potential of nanomodified cement technology for reducing clinker consumption, improving performance, and enhancing the environmental sustainability of cement production.
The microstructure and dielectric properties of manganese-doped zinc titanate (MnxZn1–xTiO3) ceramic samples were investigated as a function of manganese concentration (x = 0.1; 0.3, & 0.5). XRD analysis confirmed that the samples exhibited an ilmenite hexagonal structure, indicating the structural evolution of the material. The dielectric constant was influenced by the Mn content and increased with increasing temperature and decreased with increasing frequency. According to the findings, the dielectric loss and dielectric constant increased with temperature and decreased with frequency. The addition of trace amounts of zinc to the manganese titanate ceramics resulted in a substantial increase in the dielectric constant. The substitution of zinc ions for manganese ions effectively enhanced the dielectric properties of the ceramic samples, which highlights their potential for advanced applications.
The formation of waveguides in the bulk of sintered nanoporous glass pre-impregnated in a bismuth nitrate solution was demonstrated. The influence of laser irradiation regimes on the refractive index change and luminescence intensity in fs laser beam-written tracks was studied. It was shown that the relative luminescence intensity of the formed waveguides depends significantly on the impregnating bismuth nitrate solution concentration. The waveguides exhibit broadband (FWHM ~150 nm) luminescence in the near infrared region (1200…1500 nm) when pumped at a wavelength of 808 nm. This indicates potential for using the formed waveguides as the active medium of waveguide laser amplifiers.
The electrical properties of bidoped oxide pyrochlore Bi6/5Mn1/3Ni1/3Ta4/3O6+? (sp. gr. Fd-3m, a = 10.5038(9) ?), synthesized for the first time by the solid-phase method, were studied. According to scanning electron microscopy data, the ceramics is characterized by a porous microstructure formed by randomly oriented grains of an elongated shape. The average crystallite size determined by X-ray diffraction is 65 nm. The electrical properties of the samples were studied using an immittance analyzer at temperatures of 100…450 °C in the frequency range of 25…106 Hz. An electrical model of the sample was constructed in the form of an equivalent circuit, on the basis of which the relative permittivity (?25), the dielectric loss tangent (4 10–3 at a frequency of 106 Hz) and the activation energy of through conductivity (0.7 eV) were calculated. Two polarization mechanisms were established. Electronic polarization dominates in the high-frequency region. At low frequencies, ion-migration polarization is observed, with parameters close to the Warburg theoretical model.
In this paper the effect of chemical modification of the surface of monolithic polycarbonate on the adhesive strength of heterogeneous laminated glass are considered. The effect of chemical modification of the surface on ensuring stable adhesion between transparent chemically and physically incompatible materials is shown. The use of chemical surface modification in the production of heterogeneous aircraft glazing is proposed to improve its operational reliability and safety.
Lead-germanate glasses are a promising material for creating optical elements. However, producing such glasses with a high degree of homogeneity is associated with several technological challenges. During synthesis, phase separation can occur, in which the glass separates into several amorphous phases with different chemical compositions, negatively affecting its optical properties (scattering, absorption). Determining the exact composition is further complicated by the high lead content, which can distort analytical results. Uneven evaporation of components from the glass surface and insufficient mixing of the melting during synthesis can also lead to local variations in composition. To address these issues, a method for chemical composition mapping based on laser-induced breakdown spectroscopy (LIBS) is proposed, allowing for the visualization of the spatial distribution of elements on the sample surface. This paper presents the results of a LIBS study of lead-germanate glass samples of various compositions and demonstrates the differences in the results obtained depending on the spectral data processing method.
Technological solutions have been developed to produce composite sulfur-containing building materials based on local mineral raw materials with a high level of technical properties for use in the climatic conditions of the North and the Arctic. The use of methods of mechanical activation of mineral fillers of sulfur binder allows the use of substandard mineral raw materials in the technologies of sulfur concrete and to obtain sulfur concrete materials with a high level of physical and mechanical properties and with a strength class up to B45. The influence of the method of mechanical activation of mineral powders from natural zeolite on the formation of the structure of concretes based on sulfur binder and limestone crushing screens has been established. The effects of activation time on the properties of the developed composites have been studied, and the advantage of using the method of mechanical activation of mineral powders from natural zeolite for obtaining stable sulfur binders and concretes based on them with a high range of technical properties has been demonstrated. The use of filler mechanoactivation techniques allows for the use of substandard mineral raw materials in seroconcrete technologies, resulting in materials with high levels of physical and mechanical properties.
The defects of unetched microchannel plate blanks after their mechanical processing have been investigated. It has been established that during cutting and grinding operations, defects appear, leading to the formation of through and non-through parasitic channels, as well as to the deformation of channels bordering the frame and at the junction of multi-strand glass rods. It has been established that mainly defects appear at the stage of assembly and drawing of microchannel plate components. It has been shown that the studied defects do not affect the integral and local electrical resistance of the blanks.
A laser marking process for glass products was studied. This process involves laser-induced transfer of ink vapor to the product surface upon irradiation from the opposite side through the glass. A pulse-periodic nanosecond laser was used to form the image. The marking quality and its technological compatibility with subsequent laminated glass manufacturing operations, including thermal and barothermal exposure, were validated. Tests showed that the average strength values of the marked samples (495 and 431 MPa) were within the required range and did not indicate a critical reduction in mechanical properties compared to the permissible standards for products of this class. The obtained results confirm the feasibility of implementing this technology into the production cycle for automated product identification (alphanumeric designations, QR codes, barcodes) while maintaining operational characteristics.
Lithium-silicate scintillation glasses doped with rare earth ions are promising materials for neutron detectors. Oxyfluoride glasses, due to modification by fluorine, have improved spectral and mechanical properties compared to oxide glasses. In this work, modified by AlF3 and LiF lithium silicate glass doped with cerium ions was obtained by melt-quenching technique. Spectral and structural characteristics of glasses were studied. It has been shown that the modification of glass by 2 mol. % aluminum fluoride does not lead to crystallization. Glasses exhibit luminescence in the UV region of the spectrum when excited at 300 nm. The light yield at 137Cs (662 keV) irradiation was measured to be 30 % higher than that of its commercially available counterpart GS20 glass. When LiF is introduced into the composition, the kinetics of scintillation slows down, unlike glasses modified by AlF3, where energy transfer efficiency increases due to improved connectivity of the glass grid. The data obtained indicate the prospects of using fluoride modifiers in the creation of oxyfluoride glasses for scintillation applications.
