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This study presents the fabrication possibilities of ultra-high-temperature ceramics of ZrB2-30 vol.%SiC and (ZrB2-HfB2)-30 vol.% SiC composition using the reaction spark plasma sintering of composite powders ZrB2(HfB2)-(SiO2-C) under two-stage heating conditions. The phase composition and microstructure of the obtained ceramic materials have been subjected to detailed analysis, their electrical conductivity has been evaluated using the four-contact method, and the electron work function has been determined using Kelvin probe force microscopy. The thermal analysis in the air, as well as the calcination of the samples at temperatures of 800, 1000, and 1200 °C in the air, demonstrated a comparable behavior of the materials in general. However, based on the XRD data and mapping of the distribution of elements on the oxidized surface (EDX), a slightly higher oxidation resistance of the ceramics (ZrB2-HfB2)-30 vol.% SiC was observed. The I-V curves of the sample surfaces recorded with atomic force microscopy demonstrated that following oxidation in the air at 1200 °C, the surfaces of the materials exhibited a marked reduction in current conductivity due to the formation of a dielectric layer. However, data obtained from Kelvin probe force microscopy indicated that (ZrB2-HfB2)-30 vol.% SiC ceramics also demonstrated enhanced resistance to oxidation.

The OBJECTIVE was to study the short-term results of surgical treatment of patients with brachial artery injury in peacetime upper limb injury.METHODS AND MATERIALS. This study presents the short-term results of surgical treatment of 61 patients with brachial artery injury in peacetime upper limb injury. The study included 33 patients who were admitted to the City Hospital of St. Martyr Elizabeth in St. Petersburg from 2011 to 2022 and 28 patients who were admitted to Hospitals in the Leningrad Region from 2017 to 2022.RESULTS. All 61 patients underwent emergency surgery: autovenous prosthetics of the brachial artery was performed in 46 patients, an end-to-end anastomosis was formed in 10 patients, and a lateral suture was applied to 5 patients. In the early postoperative period, there were 3 thrombosis of the reconstruction zone, 1 amputation of a limb, 1 fatal outcome from severe blood loss.CONCLUSION. Upper limb injury with brachial artery injury without specialized assistance can lead to disability and even death of a patient, therefore requires emergency intervention by a vascular surgeon to stop bleeding, restore the main blood flow and stop limb ischemia.

Pyrolysis is one of the most common methods of end-of-life tires (ELTs) recycling. This study considered the use of carbon black from pyrolysis of ELTs as a carbon carrier for metals (Co, Ni, Cu, Fe) and their oxides to produce catalytic systems. The synchronous thermal analysis showed the positive effect of metal oxides/recovered carbon black (MOs/rCB) on ammonium perchlorate thermolysis. It was selected as a model catalytic reaction. Metal oxides/recovered carbon black (MOs/rCB) catalysts facilitated a reduction in the thermal decomposition phases of ammonium perchlorate, resulting in a significant narrowing of the decomposition interval. The greatest narrowing (22.7 °C) was observed at 103.5 °C for non-catalytic process. All tri-metallic catalytic systems showed high catalytic efficiency, providing a narrowing of the decomposition interval on average 2.5 times more in comparison with mono-metallic catalysts. Trioxide catalyst CuO/CoO/FeO/rCB showed the most significant shift in the high-temperature decomposition stage by 13% (from 334.0 °C to 293.2 °C). The activity of di-, tri-, and tetra-metallic catalytic systems was further enhanced by the synergistic effect induced by the addition of a second (or more) metal to the system. Efficient use of rCB for impregnated catalyst systems production could improve the economic efficiency of ELTs pyrolysis.

Background: Parkinson's disease (PD) is a common neurodegenerative disease characterized by rest tremor, rigidity, and bradykinesia. Assessing the severity of these symptoms is typically done using the third part of the Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS III), relying on subjective evaluations by neurologists, which may lead to challenges in result interpretation. To address this issue, incorporation of surface electromyography (sEMG) in diagnostics. Objectives: The aim of the study is to search for specific sEMG patterns that allow assessing the severity of bradykinesia. Method: This case-control study involved 8 patients with PD at Hoehn & Yahr stages 2–3, and 7 healthy volunteers. sEMG was measured while the subjects performed the ''finger tapping'' and ''hand movements'' tests of the MDS-UPDRS III. The tests were conducted both before and after levodopa intake to identify patterns indicating changes in motor functions. During the tests, we observed the peak activity of the sEMG signal, reflecting the moments of activation of individual muscle groups involved in the implementation of the movement. Peak activity was characterized by the total number of maximum sEMG signal extrema and the distance between them. The data were compared with the healthy group. Results: Peak activity increased after levodopa intake, indicating a reduction in bradykinesia. This feature partially correlates with clinicians' assessments and enhances the similarity of predictions by the MDS-UPDRS III scoring model to physician scores. Conclusions: The results show the effectiveness of using sEMG and the number of peaks corresponding to the moments of muscle activation to assess bradykinesia.

The short-term (5 min) exposure to the supersonic flow of carbon dioxide plasma on ultrahigh-temperature ceramics of HfB2-30vol.%SiC composition has been studied. It was shown that, when established on the surface at a temperature of 1615–1655 °C, the beginning of the formation of an oxidized layer takes place. Raman spectroscopy and scanning electron microscopy studies showed that the formation of a porous SiC-depleted region is not possible under the HfO2-SiO2 surface oxide layer. Numerical modeling based on the Navier–Stokes equations and experimental probe measurements of the test conditions were performed. The desirability of continuing systematic studies on the behavior of ultrahigh-temperature ZrB2/HfB2-SiC ceramics, including those doped with various components under the influence of high-enthalpy gas flows, was noted.

Leucoxene-quartz concentrate is a large-tonnage by-product of development of the Timan oil-titanium field (oil-saturated sandstones) which is not commercially used at present. High content of titanium compounds (to 50 % by weight) and lack of industrial, cost-effective, and safe technologies for its processing determine a high relevance of the work. Conventional processing technologies allow increasing the concentration of TiO2, but they are only a preparation for complex and hazardous selective chlorination. The process of pyrometallurgical conversion of leucoxene-quartz concentrate into aluminium and magnesium titanates was investigated. It was ascertained that the temperature of solid-phase reaction in Al2O3-TiO2-SiO2 system necessary for the synthesis of aluminium titanate (Al2TiO5) is 1,558 °С, and for MgO-TiO2-SiO2 system – 1,372 °С. Scaling up the process made it possible to synthesize a significant number of samples of titanate-containing products, the phase composition of which was studied by X-ray phase analysis. Two main phases were identified in the products: 30 % aluminium/magnesium titanate and 40 % silicon dioxide. In products of pyrometallurgical processing in the presence of aluminium, phases of pseudobrookite (3.5 %) and titanite (0.5 %) were also found. It was ascertained that in magnesium-containing system the formation of three magnesium titanates is possible: MgTiO3 – 25, Mg2TiO4 – 35, MgTi2O5 – 40 %. Experiments on sulphuric acid leaching of samples demonstrated a higher degree of titanium compounds extraction during sulphuric acid processing. An integrated conceptual scheme for processing leucoxene-quartz concentrate to produce a wide range of potential products (coagulants, catalysts, materials for ceramic industry) was proposed.

Objective. The article proposes design solutions aimed at the comprehensive modernization of the cold supply system of the ice palace "Puck" in Sochi, to reduce its impact on the environment.Method. A water reuse system has been created and a technology has been developed for using low-temperature heat that is released during the operation of the refrigeration machine.Result. A refrigeration plant has been developed that allows you to utilize, accumulate and direct the heat of condensation for the secondary use of thermal energy by other engineering systems at the facility, thereby reducing heat and greenhouse gas emissions into the Earth's atmosphere and increasing the technological capabilities of cooling.Conclusion. The proposed methods make it possible to make the necessary calculations and select equipment for the implementation of the developed systems in ice arenas.

The Bayanovo burial ground dating from the IX – first half of the X centuries is one of the most interesting medieval sites of Perm Cis-Urals . At the moment it is the most studied burial site of Lomovatovo archaeological culture (527 burials have been studied). The article deals with the results of the study of wooden scabbards with metal plates found during the excavation of the monument. Based on the collection, visual analysis of sources and their study with the help of different natural scientific methods, a detailed view of the design of items, the features of their manufacture and decoration techniques are given. The authors found out that birch was the main material for making the base of the scabbard. Birch, leather and textiles were also used. Thin sheets of pure copper or sheets of an alloy with a high silver content were used to make the metal plates of the scabbard. The decoration of the items was carried out with the help of various jewelry techniques. Often the artifacts were decorated with stamped wire with a grainy effect, triangles made of grains, incrustation or squeezed ornithomorphic and anthropomorphic images. Gilding applied with the help of amalgamation was also used.

A transparent white crystalline product, K[(C2F5)3PF3] (KFAP), has been synthesized via a one-pot route. Difluorotris(pentafluoroethyl)phosphorane was reacted first with aqueous HF then with K2CO3 or KHCO3 in a solution. Isolation of the intermediate, tris(pentafluoroethyl)trifluorophosphoric acid H[(C2F5)3PF3] (HFAP), was not carried out. The salt has been characterised by powder and single crystal X-ray diffraction. The single-crystal structure shows a monoperiodic coordination polymer involving K∙∙∙F bridging interactions to be present. The thermal characteristics and behaviour of KFAP have been established by simultaneous TGA-DSC measurements.

A comprehensive study of a 340 m thick lenticular-sheet body of ultramafic composition penetrated by structural well M-1 at a depth of about 2.2 km was accomplished. Its main volume is composed of plagioharzburgite; fine-grained rocks of norite and orthopyroxenite chilling zones are preserved on endocontacts. The rocks of the body are similar in composition to the rocks near the underlying ore-bearing layered intrusion – the Monchepluton. The age of intrusion of the ultramafic body is 2510 ± 9 Ma (U-Pb, ID-TIMS, zircon) and, taking into account analytical errors, is comparable with the formation period of the Monchepluton (2507-2498 Ma). According to the study of the Sm-Nd system in rocks and minerals, a positive value of the eNd (+1.1) parameter was established, similar to that in dunites and chromitites of the Monchepluton. Based on these results, the ultramafic body penetrated at depth was assigned to the magma feeding paleochannel through which the ultramafic, weakly contaminated magma entered the overlying magma chamber. This body is a unique example of a magma-feeding system for the ore-bearing layered intrusion of Precambrian age.