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The paper presents a review of CNTs synthesis methods and their application as a functional filler to obtain polymer composites for various technical purposes for strain gauges, electrical heating, anti-static coatings, electrically conductive compounds, etc. Various synthesis methods allow CNTs with different morphology and structural properties to be created, which expands the possibilities of the application of such nanoscale structures. Polymers can provide such effects as 'shape memory' and self-repair of mechanical defects. Different combinations of polymers and dispersed fillers influence the change in electrical and thermal conductivity, as well as the positive temperature coefficient of resistance, which makes it possible to achieve the effect of temperature self-regulation during electrical heating. CNTs make it possible to form PTCR (positive temperature coefficient of resistance) in elastomers at lower concentrations, which makes it possible to preserve mechanical strength and use more efficient modes of heat generation. For strain gauges, CNTs improve sensitivity to mechanical effects and extend the measurement range. The use of thermoplastic elastomers provides the temperature of PTCR operation for electric heating at the level of 200 °C (voltage 240 V), which allows such heaters to operate at a power supply from a household electrical network. CNTs-based strain gauges can provide structural condition monitoring of composite materials. [ABSTRACT FROM AUTHOR]

Strain gauges and strain gauge transducers are important tools in the field of material resistance research to measure the stresses and strains in solids. These methods and devices have a wide range of applications, from construction to mechanical engineering, where the mechanical properties of materials need to be monitored and optimized. The use of nanomaterials in strain gauges allows for more sensitive and compact sensors. Nanotechnology makes it possible to create strain gauges with improved mechanical and electrical properties. At the same time, nanomaterials have unique properties that make them ideal for use in strain gauges. This paper considers different types of composites based on polymer matrices with additives of dispersed nanomaterials, which are designed for strain gauge tasks. Thermoplastics and elastomers can be used as polymer matrices. Dispersed fillers can be based on MXene and nanomaterials such as carbon nanotubes, graphene, metals, etc. Despite the obvious advantages of strain gauges based on conducting polymers modified with dispersed structures, there are problems in creating effective strain gauges with the ability to operate under large deformations with an improved sensitivity and accuracy of measurements in a wide range. This article also provides brief information on the technical evolution of strain gauges, from wire and foil to polymer nanocomposites. A modern classification of strain gauges is provided. The disadvantages and advantages of existing strain gauges are shown. The review contains information on commercial strain gauges. The mechanisms of electrical conductivity formation in polymer composites for strain gauges are described in detail. The areas of application of polymer nanocomposite strain gauges are also specified in detail. The purpose of this review study is to determine the prospects for the use of various nanomaterials as additives in polymers to create strain gauges. The review is aimed at a wide range of readers. [ABSTRACT FROM AUTHOR]

The paper presents an overview of conductive polymer composites based on thermosetting materials, thermoplastics, and elastomers modified with carbon nanotubes (CNTs). To impart conductive properties to polymers, metal, carbon-dispersed materials, or their combinations are used. The inclusion of dispersed materials in polymers is associated with their microstructural features, as well as with polymerization methods. Such polymerization methods as melt mixing, solution technology, and introduction of fillers into the liquid phase of the composite with subsequent polymerization due to the use of a catalyst are known. Polymer composites that are capable of conducting electric current and changing their properties under the influence of an electric field, i.e., having one or more functional purposes, are called "smart" or intelligent. One such application is electric heating elements with the function of adaptive energy consumption or the effect of self-regulation of temperature depending on the surrounding conditions. A wide variety of polymers and dispersed materials with conductive properties determines a wide range of functional capabilities of the composite, including a positive temperature coefficient of resistance (PTCR) required to control temperature properties. The most effective filler in a polymer for obtaining a composite with desired properties is carbon nanomaterials, in particular, CNT. This is due to the fact that CNTs are a nanosized material with a high bulk density at a low weight, which allows for high electrical conductivity. Calculation of model parameters of polymer composites containing carbon nanostructures can be carried out using neural networks and machine learning, which give a fundamentally new result. The article contains sections with an assessment of various types of polymer matrices based on thermosets, thermoplastics, and elastomers. To impart electrically conductive properties, various options for fillers based on Ag, Au, Cu, Ni, Fe, and CNTs are considered. Methods for introducing dispersed fillers into polymer matrices are presented. Functional composites with a positive temperature coefficient and methods for their regulation are considered. The mechanisms of various electrophysical processes in conductive composites are considered, taking into account the resulting electrical conductivity based on the tunnel effect and hopping conductivity. An analysis of electric heaters based on various polymer matrices and dispersed fillers is carried out, taking into account their operating modes. Thus, the conducted review of modern scientific and practical research in the field of obtaining electrically conductive composites based on various types of polymer matrices with nanosized additives allows us to assess the prospects for the formation of functional composites for electrical heating, taking into account the mechanisms of electrical conductivity and new technologies based on machine learning and neural networks. [ABSTRACT FROM AUTHOR]

Relevance. Fractures of the proximal humerus occupy the 3rd place in the structure of fractures in the elderly. Failure to treat these injuries leads to irreversible changes in the shoulder. The main treatment for the latter is arthroplasty. The surgical treatment of this category of patients is still a difficult task. The purpose of this study was to compare the effectiveness of standard reverse arthroplasty with reverse arthroplasty in combination with the reconstruction of the external rotators of the shoulder or transposition of the latissimus dorsi. Materials and Methods. The retrospective evaluation of treatment results of 96 patients with consequences of shoulder injuries was conducted. Of these, 51 patients underwent standard reverse arthroplasty (group I), and 45 patients (group II) underwent arthroplasty with reconstruction of the external rotators of the shoulder or transposition of the latissimus dorsi. The female patients accounted for 68.8%. The duration of the injury varied from 8 months to 2.5 years, the follow-up — from 1 to 7 years (Me = 3.5). The results were assessed with VAS, ASES, UCLA scales. Results. The positive outcomes were observed in most patients. Complications: dislocations of the endoprosthesis occurred in 16.7%, infectious complications — in 5.2%, shoulder component instability — in 2.1%, fracture of the humeral diaphysis — in 3.1%, neurovascular bundle injury — in 2.1% of cases. In the patients of group I, dislocations occurred significantly more often than in the patients of group II. To reduce the risk of complications, a rational tactic has been developed for treating patients with consequences of shoulder injuries. If electroneuromyography values from the deltoid muscle were less than 40% of the contralateral side, or if mineral bone density T-score was less than 2.5 SD, arthroplasty was not performed. During arthroplasty, it is necessary to perform the direct suturing of the of the infraspinatus and teres minor tendons to the humerus. If it is impossible, the latissimus dorsi transfer is indicated. Conclusion. Reverse arthroplasty in the treatment of the humerus fractures sequelae is an effective technique. To reduce the risk of complications, it is necessary to provide the additional stability of the endoprosthesis by reconstruction of the external rotators or latissimus dorsi transfer. It is advisable to refrain from arthroplasty in cases of severe deltoid hypotrophy and severe osteoporosis.

This article presents a performance dataset of 93 Russian universities, collected from 2015 to 2018 and evaluated according to 24 indicators. These data were gathered from materials, published in the process of monitoring the effectiveness of higher education institutions by the Ministry of Science and Higher Education of the Russian Federation, Web of Science (citation-based research analytics tool InCites) and Scopus (citation-based research analytics tool SciVal) databases, and information from international ranking agencies QS, THE, ARWU. The dataset comprises the assessments of university performances according to the most important indicators used in socio-economic studies of comparative analysis of higher education system development levels in different countries: educational, scientific and research, international, financial and economic performance and international public recognition (university positions in leading international rankings). Evaluated universities are grouped pursuant to their missions: Federal Universities (FU), National Research Universities (NRU), Flagship Universities (FlU) and university-participants of the Russian Academic Excellence Project (Project 5-100). The indicators for the comparative analysis are aggregated by the type of activities and analyzed based on the calculation of median values and Displaced Ideal Method. The dataset can be helpful to researchers, university administration, specialists of higher education system, etc. Data processing can be executed using data mining methods, machine learning, and pattern analysis for the development of intellectual structures, applicable for university performance assessment in different educational systems. Presented data allows us to assert that the implementation of targeted support for leading Russian universities has a positive impact on the development of Russian higher education increasing its role on the international academic arena. Leading national research university-participants of the Project 5-100 had the greatest influence on increasing the competitiveness of Russian education in the world.

The article presents the synthesis of multi-walled carbon nanotubes (MWCNTs) on the porous nickel foam (3D-Ni) surface using the chemical vapor deposition (CVD) method, followed by the field emission characteristics of the resulting 3D-Ni/MWCNT nanocomposite structures. The characterization of the 3D-Ni/MWCNT morphology showed a uniform distribution of the "moss-like" CNT coating on the walls of the porous 3D-Ni. TEM images showed a high number of walls in MWCNTs, which made such a material resistant to destruction under conditions of strong electric fields during the field emission process. The studies also showed a high degree of chemical purity of the synthesized MWCNTs under the presented technological conditions. An increase in the emission current due to the introduction of CNTs into the structure of porous 3D-Ni is shown. 3D-Ni/MWCNTs field emitter showed a low turn-on field of 5.41 V/μm; a field enhancement factor of 915; and high operating stability. For the first time, the current mode of 3D-Ni-MWCNTs cathode was tested for compliance with the classical field emission law using the Forbes "orthodoxy" test. [ABSTRACT FROM AUTHOR]

Silicone elastomers are continuously gaining importance in a variety of industrial applications, including strain gauges, electrical heaters, electromagnetic interference, and electrostatic discharge protection coatings. But these materials have certain drawbacks such as high cost, poor resistance to solvents, low tear strength, limited high-temperature resistance, difficulty in bonding and limited abrasion resistance. Therefore, unique nanocomposites of organosilicon elastomers with metals have been prepared using MWCNTs. The prepared nanocomposites demonstrated nano-diameter structures (15–60 nm) with micron-sized fibrous structures (12–60 μm). Aluminum elongated inclusions (60 µm in size) and bronze spherical inclusions (12–30 µm) were observed in the nanocomposites. The composites containing MWCNTs, Co-Mo/Al2O3-MgO catalyst and bronze (3 wt. %) had the maximum thermal and electrical conductivity. The prepared nanocomposites were used to make the heaters. The heating of the heaters was carried out by applying a voltage of 12–24 V. The Highest temperature achieved was more than 50 °C in all the heaters. By supplying 12–24 V electricity to the heaters in the ventilation and heat recirculation system, the interior of a minibus or living space can be heated. The developed electric heater has another important economic application in temperature-controlled materials. [ABSTRACT FROM AUTHOR]

Background Total shoulder arthroplasty (TSA) is a well-established procedure for treatment of severe pathologies of the shoulder joint. However, it is a radical procedure that may result in adverse outcomes and complications. The goal was to identify causes of poor functional outcomes and complications after total shoulder replacement and search ways to prevent them. Material and methods Outcomes of 168 patients were reviewed. Reverse shoulder arthroplasty and cemented humeral fixation was employed for the majority of patients (n = 125; 74.4 %). Minimal follow-up was at least one year with an average term of 3 to 5 years. Clinical, biomechanical examinations, radiography, magnetic resonance imaging, computed tomography, electromyography, DEXA, VAS, ASES, UCLA, statistical analysis were employed in the study. Results Positive results of TSA were observed in 83.3 % of the cases and 16.7 % had poor outcomes. Patients developed implant dislocation in 9.5 %, infection in 3 %, early instability of shoulder component in 1.2 %, intraoperative fracture of the humerus shaft in 1.8 % and injury to vascular and nerve bundle in 1.2 % of the cases. Causes of poor outcomes were identified and ways of prevention presented. The best recovery was observed with anatomic shoulder replacement, integrity and functionality of the rotator cuff, absence of fatty degeneration verified with magnetic resonance imaging in sagittal plane. Clear understanding of the exact nature of osseous changes using computed tomography allows adequate positioning of implant components. Preoperative deltoid evaluation is important for posttraumatic cases as well as BMD measurements are vital for severe osteoporosis patients with application of reverse shoulder arthroplasty. Conclusion Preoperative planning and assessment of risk factors are important in preventing complications and improving outcomes of total shoulder replacement. The target audience is trauma and orthopaedic surgeons.

The measurements of electrical conductivity along (alternating electric field) and across (direct electric field)the crystallographic C axis of Cd‐doped indium selenide single crystals are carried out. The parameters of thehopping conductivity of InSe are calculated.Keywords: layered crystal, indium selenide, conductivity.