Tomsk Polytechnic University

The paper studies the influence of anisotropy of properties and structural inhomogeneity on hardness and mechanical properties of titanium Ti-4Al-3 V alloy produced by wire-feed electron-beam additive manufacturing. Tensile and compressive strength testing of the alloy specimens determines its elastic modulus and strength properties at different points. VIC-3D digital optical system is used to study the mechanical properties of the material under stress. The fractography analysis explains the observed behavior of the material under different loading. It is shown that after the tension, specimens possess close values of mechanical properties in various directions, except for their bottom, where the structure changes due to partial mixing of deposited and substrate materials. Just the material plasticity changes notably in the volume, which is the highest in the growth direction. This is probably stipulated by the low number of barriers to the dislocation motion during tension. In compressive strength testing, constrained conditions for the dislocation motion in columnar grains provide a higher strength for specimens cut in the growth direction, than for those cut in the printing direction. All this will allow us to more accurately choose the hardening technology of such materials and probably recommend methods of fabricating small-sized parts.

In this paper, a series of KGaGeO4:0.01Cr³⁺, xIn³⁺ (KGGO:0.01Cr³⁺, xIn³⁺, x=0~0.08) phosphors were synthesized by high temperature method. KGGO:0.01Cr³⁺ has a far red emission in the range of 600~900 nm ascribing to the 4T2→4 A2 spin‐allowed transition of Cr³⁺. With the incorporation of In³⁺, KGGO:Cr³⁺, In³⁺ shows a near‐infrared (NIR) broadband emission in the range of 700~1200 nm, with red shift of the emission peak by 136 nm, and FWHM of 185 nm. The electroluminescence efficiency of NIR pc‐LED prepared by KGGO:0.01Cr³⁺, 0.02In³⁺ is as high as 19 % under the output power of 25 mW, which can be applied in the night vision technology and microbial growth.

The influence of the dispersion of the particles of the synthesized nickel-zinc ferrite powder on its structural and magnetic properties is shown. Ferrite powder was produced using ceramic technology. The average particle size was varied using the mechanical activation method. According to X-ray diffraction analysis, laser diffraction and thermal analysis, regularities were established for the formation of the properties of nickel-zinc ferrite depending on the modes of mechanical activation.

Near-field focusing of an electromagnetic wave on the assembly of hexagonally asymmetric arranged close-contact nanofibers into a cylindrical Janus metalens is considered for different fiber sizes and optical properties. We propose combining the meta-material concept with a photonic hook based on the finite-difference time-domain technique. Simulation results show that the cylindrical meta-photonic Janus structure produces the focal region of enhanced optical intensity, which exists in the spatial form of a localized structured light known as a photonic hook. A detailed study of all key parameters of a photonic hook depending on the Janus metalens topology and optical properties of the fiber filling is carried out. The structure conditions have been determined for the beam waist of a photonic hook that is less than the diffraction limit. This Janus cylindrical metalens may contribute to the versatile control of photonic hook generation in the applications of bio-photonics and optical microscopes.

Mathematical modeling of heat transfer and carbon dioxide diffusion processes in a closed room with a working gas infrared emitter and air exchange system was performed. The distribution of CO2 produced by burning natural gas in the emitter and generated by an additional source was taken into account. Temperature fields, flow lines and CO2 concentration values were obtained at different air flow rates. The operating parameters of the systems for creating scheduled thermal conditions and air exchange were analyzed.

With the over-use of tetracycline (TC) and its ultimate accumulation in aquatic systems, the demand for TC removal from contaminated water is increasing due to its severe threat to public health. Clay minerals have attracted great attention as low-cost adsorbents for controlling water pollution. The objective of the present study was to measure the adsorption behavior and mechanisms of TC on allophane, a nanosized clay mineral with a hollow spherical structure; to highlight the advantage of the allophane nanostructure, a further objective was to compare allophane with halloysite and montmorillonite, which have nanostructures that differ from allophane. Structural features and surface physicochemical properties were characterized by transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta potential, N2-physisorption, and acid–base titration. The adsorption data showed that TC adsorption followed the pseudo-second order and Langmuir models. The adsorption was pH dependent, as all three clay minerals performed better under neutral to weakly alkaline conditions and maintained high adsorption performance in the presence of co-existing Na+/K+/Ca2+/Mg2+ cations. Regeneration of the adsorbent was excellent, with efficiencies exceeding 75% after five recycles. By comparison, allophane always exhibited the greatest adsorption capacity, up to 796 mg g–1 at ~pH 9. The TC adsorption on allophane and halloysite was dominated by inner-sphere complexation, together with a small amount of electrostatic adsorption, while that on montmorillonite involved mainly interlayer cation exchange. The findings provide insights into the effects of nanostructures of clay minerals on their TC adsorption performance and highlight the huge potential of allophane as an efficient and inexpensive adsorbent for TC removal.

This study presents the synthesis of new fluorosulfate derivatives of 1,4-naphthoquinone by the SuFEx reaction. Anticancer properties of obtained compounds were studied on PC-3 (prostate adenocarcinoma), SKOV-3 (ovarian cancer), MCF-7 (breast cancer), and Jurkat cell lines. All the studied compounds showed higher cytotoxic effects than Cisplatin. The DFT method was applied to determine the electronic structure characteristics of 1,4-naphthoquinone derivatives associated with cytotoxicity. A method of determination of 2,3-dichloro-1,4-naphthoquinone (NQ), 3-chloro-2-((4-hydroxyphenylamino)-1,4-naphthoquinone (NQ1), and 4-((3-chloro-1,4-naphthoquinon-2-yl)amino)phenyl fluorosulfate (NQS) in a pharmaceutical substance using an impregnated graphite electrode (IMGE) was developed. The morphology of the IMGE surface was studied using scanning electron microscopy (SEM). The electrochemical behavior of NQ, NQ1, and NQS was studied by cyclic voltammetry (CV) in 0.1 M NaClO4 (96% ethanol solution) at pH 4.0 in a potential range from −1 to +1.2 V. Electrochemical redox mechanisms for the investigated compounds were proposed based on the determining main features of the electrochemical processes. Calibration curves were obtained by linear scan voltammetry in the first derivative mode (LSVFD) with the detection limit (LOD) 7.2 × 10−6 mol·L−1 for NQ, 8 × 10−7 mol·L−1 for NQ1, and 8.6 × 10−8 mol·L−1 for NQS, respectively.

BACKGROUND: Size and localization, as well as clear differentiation between intact tissue and infarcted area, are important for clinical diagnosis and precision medicine. This work is based on the study of radiomics features capable of differentiating areas of infarcted and distant tissue from the infarct area using data from non-contrast cine cardiac MRI imaging. AIM: Evaluation of the possibilities and informativeness of radiomics analysis in detection of postinfarction areas of the left ventricular myocardium in patients with ischemic cardiomyopathy by contrast-free cine cardiac MRI images. MATHERIALS AND METHODS: The results of contrast enhancement cardiac MRI with of 33 patients undergoing surgical treatment for ischemic cardiomyopathy were analyzed. Texture analysis was performed on 66 sections of cine cardiac MRI images, and 105 texture characteristics were determined for each of them. Cardiac MRI was performed according to the standard technique on a Vantage Titan (Toshiba) 1.5 T. Texture analysis was performed using 3D slicer-version 5.2.2 software, SlicerRadiomics RESULTS: Collinearity diagrams of the features were constructed. We also identified the features with zero importance and established the importance of the features using the gradient boosting algorithm. In addition, the cumulative importance of the features as a function of their total number was estimated. Using the method of identifying features with low importance, we identified the parameters with the lowest importance that do not affect the indicated total level. Using the method of identifying features with a single value, we did not find features with a single unique value. In addition, ROC curve for Lasso logistic regression (Se =57.14% Sp=71.43%, AUC=0.76) was generated based on the results of the analysis. The main result of this study is the identification of radiomics features able to characterize the areas corresponding to postinfarction cardiosclerosis and intact LV wall on the basis of cine cardiac MRI images. CONCLUSION: This study has shown that the use of radiomics analysis on contrast-free cine cardiac MRI images is a promising approach to identify areas corresponding to myocardial infarction and intact wall and could potentially be used as to identify areas of postinfarction cardiosclerosis in patients with ischemic cardiomyopathy without the use of contrast agents.

Non-destructive testing is an integral part of quality inspection for critical products. The complex structure of metalpolymer hydrogen cylinders makes it difficult to reliably detect defects using a single type of an NDT technique. In this context, the application of hybrid NDT is of interest. This paper considers the combined use of acoustic and thermal techniques of defect detection and the fusion of their results. Experimental verification has shown that the fusion of thermal and acoustic inspection data using the approach developed in this study provides an increase in defect detection compared to the separate use of these types of NDT methods.