Study of Dimensional Stability of Metal-ceramic Prostheses By Holographic Interferometry

Presents results of a study of deformation of metal-ceramic bridge prostheses manufactured in a variety of ways. Registration of deformations was carried out using double-exposure holographic interferometry. According to the experimental data, an optimal method of making dentures. Keywords: bridge prosthesis, deformation, holographic interferometry, the method of two exposure

Estimating the Brittle Strength of Nuclear Fuel Material

The development of nuclear energy involves use of promising nitride nuclear fuel in reactors of the 4th generation. This will require improving the fuel production technology as well as its test methods. For estimation of the strength of the nuclear fuel material as well and for further refinement of nuclear fuel test technology we propose to use small discoid samples, similar in shape to the elements of nuclear fuel in the context of ”Brazilian test” (compression applied to disk specimen in the median plane). We present here the results of testing small discoid specimens made of brittle materials such as cast iron and graphite (both being considered as possible model materials for the nuclear fuel). We compared these materials to nuclear fuelitself (as represented by uranium dioxide). In addition the effect of the specimen size on resistance to destruction was investigated. The type of deformation and fracture found in samples made from cast iron suggests that this material cannot be used as a model for the nuclear fuel. At the same time the results obtained in tests on samples composed of graphite ARV-1 were in good agreement with the results oftests on uranium dioxide. Using the data obtained in this study, a calculation formula for determining the strength of the nuclear fuel material based on the “Brazilian test” results is proposed

The Mechanical Testing of Materials Using the Method of Digital Image Correlation

The mechanical testing of materials is regulated by standards, which established requirements for samples, test equipment, testing conditions and methods of processing the results. When performing tests, it is important to control the quality of the sample surface, its geometric dimensions and deviations from a predeterminedshape. Not less important stage of the testing is to control the fixing of the test specimen in the test equipment and the need to render its stress-strain state in the process of loading.Using the method of digital image correlation when conducting mechanical testing allows you to successfully control all phases of mechanical testing, from the quality of specimen production, testing equipment, to visualize the stress-strain state and its compliance with the adopted design scheme

Tumor bed brachytherapy for locally advanced laryngeal cancer: a feasibility assessment of combination with ferromagnetic hyperthermia

Purpose. To assess the feasibility of adding hyperthermia to an original method of organ-preserving brachytherapy treatment for locally advanced head and neck tumors. Methods and materials. The method involves organ-preserving tumor resection and adjunctive high-dose-rate (HDR) brachytherapy delivered via afterloading catheters. These catheters are embedded in a polymeric implant prepared intraoperatively to fill the resection cavity, allowing precise computer planning of dose distribution in the surrounding at-risk tumor bed tissue. Theoretical and experimental analyzes address the feasibility of heating the tumor bed implant by coupling energy from a 100 kHz magnetic field applied externally into ferromagnetic particles, which are uniformly distributed within the implant. The goal is to combine adjuvant hyperthermia (40 °C–45 °C) to at-risk tissue within 5 mm of the resection cavity for thermal enhancement of radiation and chemotherapy response. Results. A five-year relapse free survival rate of 95.8% was obtained for a select group of 48 male patients with T3N0M0 larynx tumors, when combining organ-preserving surgery with HDR brachytherapy from a tumor bed implant. Anticipating the need for additional treatment in patients with more advanced disease, a theoretical analysis demonstrates the ability to heat at-risk tissue up to 10 mm from the surface of an implant filled with magnetically coupled ferromagnetic balls. Using a laboratory induction heating system, it takes just over 2 min to increase the target tissue temperature by 10 °C using a 19% volume fraction of ferromagnetic spheres in a 2 cm diameter silicone implant. Conclusion. The promising clinical results of a 48 patient pilot study demonstrate the feasibility of a new organ sparing treatment for laryngeal cancer. Anticipating the need for additional therapy, theoretical estimations of potential implant heating are confirmed with laboratory experiments, preparing the way for future implementation of a thermobrachytherapy implant approach for organ-sparing treatment of locally advanced laryngeal cancer

Methods of Research of Shape Memory Effect and Superelasticity in the Alloy Ti-22%Nb-6%Zr

Cyclic tensile tests were carried out as applied to annealed foils of the superelastic Ti-22Nb-6Zr alloy (at.%) as well as indentation of these foils with an increasing amplitude of indenter intrusion in the sample at temperatures lowering from 20∘ down to -60-70∘C. Mechanical tests were performed on samples cut along andacross the rolling direction. According to the results of measurements of mechanical properties, it is established that during cyclic stretching of foils in the rolling direction, superelasticity manifests itself, and also material training is observed with subsequent preservation of the maximal renewable deformation. When the foil is loaded in the transverse direction, no superelasticity is observed, moreover, some samplesare destroyed even with a deformation of 2%. With a decrease in the annealing temperature of foils, the curve of the continuous change of loading with the depth of indenter penetration undergoes substantial changes, which indicate the appearance of a superelastic deformation under the indenter. Curves of monotonic loading and discharge undergo an inflection, and the plastic deformation region is substantially reduced. From the discharge curves in this case, we can calculate two elastic modules, typical for the usual elasticity and superelastic behavior of the alloy. In general, the main characteristics of the continuous indentation curve depend on the amount of the martensitic phase. The dependence of the modules of elasticity for foils, coolingdown to -(60-70∘C), and for their subsequent heating up to the room temperature is constructed

Physio-mechanical Materials Testing Using Scanning Contact Potentiometry Method

To study the processes of forming and growing embryonic fatigue cracks in steel EI-847 when tested under a uniaxial tension at constant load; adapting the method of scanning contact potentiometry using the INSTRON-5982 machine. The embryo was detected on the sample surface- in the yield point- and stably tracked by theequipment indications at higher loads up to the fracture point. Keywords: scanning contact potentiometry, electrical non-destructive testing, tension testing, fatigue crack, time-frequency signal analysis

Short-term Mechanical Properties of Fe-Cr-Al-Si Alloys

The purpose of this work is to study the short-term mechanical properties of Fe-Cr-AlSi-based alloys. Within the framework of this work, alloys with a chromium content of 5 to 14 wt%, aluminum from 0 to 4 wt%, and silicon from 0 to 4 wt% are considered. The samples were tested in three different states - in the deformed state (cold rolling by 80%), and also after annealing at a temperature of 450 and 650 ∘C with a duration of 1000 h.As a result, the characteristics of the strength and plasticity of alloys in the deformed state, as well as after provoking annealing, were obtained. It is shown that embrittlement isn’t observed in the investigated composition region and annealing conditions, and the strength of the alloys is directly proportional to the sum of the alloying elements Al + Si. Keywords: cladding; VVER; tolerant fuel, ferrite steel; Corrosion-resistant steel, tensile strength, yield strengt

Религиоведение в высшей школе: сравнительный анализ содержания учебных изданий

The problem of the content of educational publications for university students on religious studies, recently published, is an important and urgent research problem, as it shows the dependence of their content on sociocultural changes taking place in the field of domestic religious studies: object, research methodology, scientific approaches and principles. Research Methods. To identify factors affecting the content of educational publications, a comparative analysis was carried out (total number - 38) according to the criteria: time of publication of the educational publication; orientation of the educational publication (specialty, field of study, level of education); structure of religious studies as a system of knowledge about religion; the definition of religion as a basic concept; neutrality of the position of the authors of educational publications in relation to a particular religion. Textbooks and teaching aids prepared by teams of authors and published in large Russian publishing houses or in university publishing houses were analyzed. Research results and discussion. Based on the analysis, the evolution of the content of educational publications, its correlation with the ongoing sociocultural changes and vectors of the study of religion in Russian and foreign science is shown. Changes in the structure of knowledge and the field of religious studies, differences in the ways of presenting material were revealed; the applied character of some sections for students of the areas of "Law", "Social Work" is noted, taking into account the features of future professional activity. There are fixed differences in the "neutrality" of the author's position in relation to a particular religion, and equidistance from religious institutions or faiths. Conclusions. Russian educational publications on religious studies have undergone significant ideological and substantial changes since the Soviet era of scientific atheism. In the studied Russian educational publications, there is a systematic knowledge of religion that has been established in the academic community of religious scholars. However, the share of new contemporary topics about religion of a debatable nature is not high. It was revealed that the authors of educational publications, affiliated with major religious centers, occupy an objective, neutral position in the description of religions and faiths. The subjectivity, the lack of neutrality of the authors, as well as a certain non-observance of the secular nature of higher education in Russia was found in educational publications of institutions that do not have specialized departments of religious studies. The organization of material in educational publications makes it difficult for students to independently compare religions. © 2020 LLC Ecological Help. All rights reserved

Transport Properties of Spin Field-Effect Transistors Built on Si and InAs

Abstract We investigate the properties of ballistic spin fieldeffect transistors (SpinFETs). First we show that the amplitude of the tunneling magnetoresistance oscillations decreases dramatically with increasing temperature in SpinFETs with the semiconductor channel made of InAs. We also demonstrate that the [100] orientation of the silicon fin is preferred for practical realizations of silicon SpinFETs due to stronger modulation of the conductance as a function of spin-orbit interaction and magnetic field

Multi-criteria analysis of deep pits sustainable development strategy

Relevance. Long periods of development of steeply dipping deposits necessitate multiple adjustments of mining and technical system throughout an open pit life cycle. The decisions made determine the development strategy of a mining enterprise for a long period. The complexity of making such strategic decisions depends on numerous influencing parameters. These parameters have a different impact, have a variety of units of measurement, target values, and are not only quantitative but also qualitative. There is a need for new approaches to the choice of development strategy of the mining and technical system of an open pit, as well as its main subsystem – the opening-up of an opencast system. It is proposed to base these approaches on multi-criteria decision-making methods that consider many influencing parameters. Aim. Development of a methodology for choosing a strategy for sustainable development of the deep open pit mining and technical system based on multi-criteria decision-making methods and assessment of the opening system parameters. Objects. Mining enterprise, mining and technical systems, opening system. Methods. Literature review, system analysis, multi-criteria decision making.   Results. The authors have determined the main strategies for development of the mining and technical system for deep open pits. These strategies aim at achieving the sustainable development of the mining and technical system: adjustment of the current stage mining parameters; transition to a new stage of mining; transition to a combined open-underground mining; mine closure. The key role of the opening system in the structure of the mining and technical system is substantiated to ensure its sustainable development. The authors systematized the main parameters for evaluating the pit opening system and set target values for each parameter. A review of the main multi-criteria decision-making methods used to solve various problems in the mining industry is made. A rank coefficient is proposed for choosing the mining and technical system development strategy. The calculation of this coefficient is based on a combination of the fuzzy AHP and CRADIS multi-criteria methods. A method was developed for selecting a strategy for sustainable development of the mining and technical system of deep open pits. A case study was conducted on the conditions of the Maly Kuibas open pit. The obtained results strongly suggest that the best strategy with the highest ranking is the transition to the combined development method